RU2844196C1 - Anti-icing systems and control thereof - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to automotive anti-icing systems. System for heating the exterior of an aircraft comprises a plurality of separate heating elements disposed on the skin, a sensor disposed on the skin at location (3308) that corresponds to an area of relatively low temperature within heating model (3302, 3304, 3306), and a control system coupled to the heating elements and the sensor. Control system is configured to control power supplied to the heating elements in response to the output signal from the sensor, determining, based on an output signal from the sensor, a characteristic of the skin of the aircraft at said location (3308), comparing the value of the characteristic with a reference characteristic and applying power, in response to determination that characteristic value indicates freezing in specified location, to heating element.

EFFECT: decreased overall dimensions.

42 cl, 75 dwg

Description

AREA OF TECHNOLOGY

This application relates to heating systems for conductive materials.

LEVEL OF TECHNOLOGY

Many conductive surfaces, such as those on automobiles, aircraft, and satellites, are exposed to freezing temperatures and icing during everyday use. Ice or water accumulation on the conductive surfaces of these structures can lead to inefficient or unsafe operating conditions. For example, ice accumulation on aircraft wings can lead to decreased lift and increased drag.

Many of these structures are not equipped with heating systems or are equipped with heating systems that require the use of bulky electronic equipment or other types of equipment. The use of bulky devices in this industry is a problem.

DISCLOSURE OF THE ESSENCE OF THE INVENTION

This application describes technologies for heating a conductive surface. These technologies typically involve the use of high-frequency alternating current signals (e.g., with a frequency greater than 1 kHz) to provide a current density in a target region of a conductive volumetric medium (e.g., a conductive material), which results in Joule heating of the medium.

Joule heating, also known as ohmic heating or resistive heating, is a process in which heat is generated when an electric current passes through a conductor. The amount of heat generated by a conducting medium depends on the amount of current passing through the medium and the electrical resistance of the medium. Therefore, heating can be controlled (e.g. increased or decreased) by adjusting the current, voltage, resistance, or a combination of these.

The resistance of a particular conductor can be increased by limiting the volume of the conductor in which the current can flow and by increasing the length along which the current flows. Embodiments of the disclosure of the present invention can be made with the possibility of implementing heating in a bulk medium by controlling the mechanisms of formation (e.g. narrowing, lengthening, etc.) of the current in a conducting medium (e.g. a bulk medium, a conductor): for example, using the skin effect and the proximity effect. Both effects are based on the flow of high-frequency alternating current through a conducting medium to be heated. The skin effect limits the current flow by using the tendency for alternating electric current to be distributed in a conductor in such a way that the current density increases near the surface of the conductor and decreases in the direction into the conductor. The proximity effect can be used to further limit the current flow in a conductor by placing another alternating current path near the existing current flowing in the conductor. The proximity effect can also provide for the extension of the current path.

For example, embodiments of the disclosure of the present invention are configured to increase the resistance of a bulk medium along a current path through the medium by limiting the current flowing along this path. Accordingly, embodiments can provide increased heating efficiency in conductive media while reducing the current required to generate heat. That is, by increasing the effective resistance of a conductive medium along a particular current path, less current may be required to perform Joule heating of the medium than would otherwise be required.

The subject matter of the present invention described herein may be implemented in such a way as to provide one or more of the following advantages. A lighter and less bulky electrical system may be used to heat the conductor. In addition, the heating may be localized in the target area so as not to overheat the heating system circuit. The heating system may be more efficient, for example, by generating heat directly in the bulk medium itself (for example, an aircraft wing), instead of generating heat in a heating element or a heating layer attached to the bulk medium. The system may also use less current and voltage for heating, which potentially increases safety and reliability. In some embodiments, mechanical stress in the component may also be reduced. Installation or upgrade of the system may be easier, faster, or cheaper. Maintenance of the system may be cheaper or easier. The system may not require intervention when installed in existing systems. The system can remove icing faster.

Detailed information on one or more embodiments of the subject matter of the present invention is given in the attached drawings and in the following description. Other features, aspects and advantages of the subject matter of the present invention will become apparent from the description, drawings and claims.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a schematic representation of an example of an installation for heating a volumetric medium.

Fig. 2A-2B are schematic diagrams illustrating an exemplary apparatus for heating a bulk medium in which the skin effect is used to concentrate the current density in a first direction in a bulk conductor.

Fig. 3 is a graph showing the increased current density concentration as a function of the supplied alternating current, which occurs due to the skin effect.

Fig. 4A-D are schematic diagrams illustrating exemplary installations for heating a bulk medium in which the proximity effect is used to concentrate the current density in a second direction in a bulk conductor.

Fig. 5A-B are graphical simulation results showing the increased current density concentration in the bulk conductor near the second conductor as a function of the distance between the conductors, which occurs due to the proximity effect.

Fig. 6A is a schematic representation of an exemplary apparatus for heating a bulk medium using an electrode array.

Fig. 6B-D are schematic representations of exemplary installations for heating a bulk medium using various electrode devices.

Fig. 7 is a schematic representation of an example signal conversion block including the main sub-blocks for conversion to standardized power supply and generation of alternating current.

Fig. 8 is a schematic representation of an exemplary signal conversion unit including the main sub-units of conversion to standardized power supply, AC generation, and control.

Fig. 9A is a schematic representation of an exemplary standardized power conversion sub-block including a flyback converter and a common mode choke.

Fig. 9B is a schematic representation of an exemplary flyback converter.

Fig. 10A is a schematic diagram of an exemplary AC power generation sub-block including a dual MOSFET class D amplifier, a temperature compensated crystal oscillator, and a gate driver.

Fig. 10B is a schematic diagram of an exemplary class D switching amplifier.

Fig. 10C is a schematic diagram of an exemplary AC power generation sub-block including a dual MOSFET class D amplifier, a temperature compensated crystal oscillator, a gate driver, and a low power conversion stage.

Fig. 11 is a schematic representation of an exemplary control sub-unit including a microcontroller and a low power conversion stage.

Fig. 12 is a schematic representation of a circuit for adjusting the impedance between a source and a load.

Fig. 13A-D are schematic representations of exemplary structural blocks of an impedance adjustment circuit.

Fig. 14 is a schematic representation of an exemplary control circuit block including a passive control sub-block.

Fig. 15A is a schematic representation of an exemplary control circuit block including an active control sub-block and a control sub-block.

Fig. 15B is a schematic representation of an exemplary control circuit block including an active control sub-block, a low power conversion stage, and a control sub-block.

Fig. 16 is a schematic representation of the cable stages in the exemplary heating system.

Fig. 17 is a schematic representation of an exemplary electrode for a heating system.

Fig. 18A is a schematic representation of an example of a fastening between an electrode and a volumetric medium by means of a soldered connection.

Fig. 18B is a schematic representation of an example of fastening between an electrode and a volumetric medium by means of rivets.

Fig. 18C is a schematic representation of an example of fastening between an electrode and a volumetric medium by means of an airtight tape.

Fig. 18D is a schematic representation of an example of a combined fastening between an electrode and a bulk medium.

Fig. 19 is a sectional view of an exemplary connecting strip for supplying high frequency heating signals to a volumetric medium in accordance with embodiments of the disclosure of the present invention.

Fig. 20 shows an example diagram of the arrangement of the connecting strips according to Fig. 19 on the wing of an aircraft.

Fig. 21 shows a top view of several exemplary connecting strips to illustrate various configurations of the conductive layer in the connecting strip.

Fig. 22A shows a graph of the simulated current density created in the aircraft skin by the example connecting strip and the electric field density between the connecting strip and the aircraft skin.

Fig. 22B is a graph of the simulated current density created in the aircraft skin shown in Fig. 22A.

Fig. 23 shows schematic representations of the arrangement diagrams of several example arrangements of the conductive layer in the connecting strip.

Fig. 24A shows a sectional view, taken along line A-A', of a connecting strip according to the arrangement diagram A in Fig. 23.

Fig. 24B shows a sectional view, taken along line B-B', of a connecting strip according to the arrangement diagram B in Fig. 23.

Fig. 24C shows a sectional view, taken along line C-C', of a connecting strip according to arrangement diagram C and arrangement diagram D in Fig. 23.

Fig. 25A is a sectional view of an exemplary configuration for attaching a connecting strip to a volumetric medium.

Fig. 25B is a sectional view of another exemplary configuration for attaching a connecting strip to a volumetric medium.

Fig. 26A is a sectional view of the connecting strip with a double-sided adhesive bottom layer before installation on a bulk medium; Fig. 26B is a sectional view of the connecting strip of Fig. 26A installed on a bulk medium.

Fig. 27A-27F show sectional views of various embodiments of built-in connecting strips.

Fig. 28 shows schematic images of embodiments of the connecting strip connector.

Fig. 29 shows schematic images of another embodiment of the connector of the connecting strip.

Fig. 30 is a block diagram of a first exemplary system for heating a bulk medium using connecting strips according to embodiments of the disclosure of the present invention.

Fig. 31 is a block diagram of a second exemplary system for heating a bulk medium using connecting strips according to embodiments of the disclosure of the present invention.

Fig. 32 is a block diagram of a third exemplary system for heating a bulk medium using connecting strips according to embodiments of the disclosure of the present invention.

Identical elements are indicated in different drawings by the same reference numbers and designations.

Fig. 33 is an illustration showing an exemplary portion of a pilot's field of view on an aircraft with a superimposed display of wing temperature.

Fig. 34 is a schematic diagram illustrating time domain reflectometry (TDR) techniques.

Fig. 35A is a graph showing a comparison of two transmission lines measured using time domain reflectometry, one line including a 2 meter long connector.

Fig. 35B is a graph showing a frequency domain analysis showing the change in impedance after an impact dent is formed.

Fig. 36 is a graph illustrating a comparison of two transmission lines measured using time domain reflectometry, with one of the lines having a dent in the test panel.

Figs. 37A, 37B, and 37C illustrate exemplary flight deck alert displays.

Fig. 40 shows graphs of impedance and temperature versus time for a connecting strip during a deicing operation.

Fig. 41 is a three-dimensional graph of the dielectric constant of an exemplary acrylic adhesive material over a range of operating temperatures.

Fig. 42 is a graph of the dielectric constant of an exemplary acrylic adhesive material over a range of operating temperatures.

Fig. 43 shows the frequency response graphs for a healthy line and a faulty line.

IMPLEMENTATION OF THE INVENTION

In the heating system according to the present invention, alternating current is used to increase the effective electrical resistance of conductive materials (e.g. aluminum, carbon fiber composites) in order to facilitate their heating. In general, the heat generated in the conductive material can be used to melt ice formed on the surface of the conductive material. In addition, the heat can be used to maintain an elevated temperature of the conductive materials in order to prevent vapor deposition on the surface or to prevent water from freezing on the surface, as well as to prevent freezing precipitation (e.g. snow, ice pellets, fog, freezing rain) from accumulating on the surface. For example, the heat generated in the conductive material can spread (e.g. dissipate) throughout the conductive material. In addition, the generated heat can cause convection at the interface of the conductive material and any liquid on the surface, for example, to heat the liquid and prevent it from freezing.

An alternating current can be used to create a number of electromagnetic effects that increase the effective resistance of a conductive material, which facilitates heat generation using Joule heating in a conductive material. Such effects include the skin effect, the proximity effect, induction, eddy currents, hysteresis losses, and dielectric losses. With regard to the skin effect, if the frequency of the current in the conductor is set to a sufficiently high value, most of the current will pass through a skin depth of the conductive material that is significantly smaller than the geometric thickness of the conductive material. In addition, a certain device geometry can be used to create a proximity effect in the conductive material, which will further limit the width of the current density and thereby further increase the effective resistance along the current path in the conductive material. A combination of these two effects can be used to increase the electrical resistance of the conductive material and, as a result, Joule heating.

For example, Joule heating is generally associated with the heat generated when an electric current passes through a conductor. The heat generated in a given current-carrying conductor is proportional to the resistance of the material multiplied by the square of the root mean square of the current amplitude:

The heat generated by a heating element is typically increased by increasing the current passing through the conductor and by providing heating elements that have a relatively higher resistance. However, in embodiments of the present disclosure, Joule heating is achieved by effectively using certain electromagnetic phenomena (e.g., the skin effect and the proximity effect) to limit the localized current density in the bulk medium. This limitation of the current density results in an increase in the effective resistance along the current path in the bulk medium. Although the specific effects may vary in different materials having different geometries, the effective resistance for a given length along the current path through the bulk medium can generally be represented as follows:

where ρ is the specific resistance of the material through which the current passes, l is the length of the current path, and A _eff is the limited cross-sectional area of the current density. In embodiments of the disclosure of the present invention, electromagnetic phenomena are used to reduce A _eff to an area smaller than the cross-section of the bulk medium along the current path, due to which the said effective resistance of the bulk medium increases above the effective resistance of the bulk medium to direct current.

In some embodiments of the disclosure of the present invention, these electromagnetic phenomena can be used to increase the length of the current path through the bulk medium. For example, as described below with reference to Fig. 4D, the technologies described herein can be used to "direct" the current path along an indirect route (e.g., a serpentine path) between two electrodes attached to the bulk medium. The indirect route can create a current path whose effective length (l _eff ) is greater than the substantially direct path that is typically formed when passing a current between two electrodes in the absence of such electromagnetic effects as, for example, the proximity effect. Thus, the systems described herein are configured to increase the length/path of the current to an effective length (l _eff ) that is greater than the direct path along which the current passes in the absence of the various systems and conductor arrangements described herein. Accordingly, such embodiments can increase the effective resistance (R _eff ) both by limiting the effective area (A _eff ) of the cross-section of the current passing through the bulk medium and by increasing the effective length (l _eff ) that the current passes through the bulk medium, which further increases the effective resistance of the bulk medium above the effective resistance of the bulk medium to direct current. In such embodiments, the effective resistance can be generally represented as follows:

By using such technologies, embodiments of the present disclosure can provide high localized resistance in conductive bulk materials (e.g., aluminum, copper, steel, and their alloys).

Skin effect, as used herein, generally refers to the tendency of an alternating electric current to be distributed unevenly in a conductor such that the current density is greater near the surface of the conductor and decreases with increasing distance from the surface of the conductor. The intensity of the skin effect increases with increasing frequency of the current and the conductivity of the material through which the current flows. In some embodiments of the disclosure of the present invention, the skin effect can be controlled such that the electric current flows more along the outer surface of the conductor (e.g., "in the depth of the skin layer") at higher frequencies of alternating current.

In general, the skin effect in a conductor can be represented by the following formula:

where J is the current density, J _п is the surface current density, d is the depth of the point at which the current density is calculated, δ is the skin depth, ρ is the specific resistance of the conductor, ω is the angular frequency of the current, μ is the magnetic permeability of the conductor, ε is the permittivity of the conductor. In the case of a cylindrical conductor with a base radius R, the current density can also be determined as follows:

where J ₀ is the Bessel function of the first kind of zero order.

In the case of a rectangular plate of infinite length and width carrying a surface current, the skin effect can be represented by the following formula:

where J _s is the forced component of the surface current, σ is the plate conductivity, e is the plate thickness, and sh is the hyperbolic sine function. For example, the graph shown in Fig. 3, which will be discussed in more detail below, shows an example of current density limitation in the depth of the material (e.g., in the skin depth) in a cylindrical conductor caused by the skin effect. As described above, such a limitation of the effective cross-section increases the effective resistance of the conductor.

For example, the graph shown in Fig. 3, which will be discussed in more detail below, shows an example of current density limitation in the depth of the material (e.g., in the skin depth) caused by the surface effect.

The proximity effect, as used herein, generally refers to the effect of an alternating current flowing in a first current path (e.g., a conductor) on the density of alternating current flowing in a second, nearby current path. For example, as shown in Fig. 5A-5B and described in more detail below, an alternating current in a first current path causes a "concentration" or limitation of the density of alternating current in a second current path around the first current path. In embodiments of the disclosure of the present invention, for example, the density of current passing through a bulk medium is "attracted" to another conductor carrying an alternating current when the conductor is placed near the passage of current through the bulk medium. The degree and direction of current density limitation (e.g., concentration) caused by the proximity effect depends on several variables, including, for example, the distance between two or more alternating current paths, the direction of current flow in individual current paths relative to each other, the frequency of the alternating current in the current paths, and the magnitudes of the individual currents in the current paths.

For better understanding, the heating system according to the present invention will be described with reference to a deicing and anti-icing system for the exterior surface of an aircraft as an exemplary context. However, the heating system according to the disclosure of the present invention can be used in other contexts, including, but not limited to, heating the surfaces of other aircraft, drones, wind turbines, units involved in cryogenic operations, heat pumps, automobiles, radio towers, railroad tracks, manned or unmanned military vehicles, roofs or heating other conductive surfaces on which it is desirable to control ice formation and water accumulation. The heating system can be used to deicing or to prevent icing. In some embodiments, the heating system can be used to heat less conductive materials, for example, by applying a conductive layer on top of or inside a non-conductive material. Such embodiments can be used to heat road surfaces (e.g., roadways), building materials, roofs, floors, or other low-conductive or non-conductive materials.

De-icing, as used herein, generally refers to the removal of snow, ice, or frost (collectively referred to as "ice") from a surface. In some embodiments, the heating system is configured to melt only a portion of the ice present on the conductive surface. The ice may then be removed from the surface (e.g., by sliding off the surface after the melting process has begun and the bonds between the ice and the surface have been broken).

As used herein, icing prevention generally refers to preventing the formation or adhesion of snow, ice, or frost (collectively referred to as "ice") on a surface. In some embodiments, a heating system maintains a surface temperature high enough to prevent ice from forming on the surface and to prevent ice from adhering or accreting (e.g., due to freezing precipitation such as snow, frost, sleet, freezing rain, etc.).

Fig. 1 shows a block diagram of an example heating system 100 for heating a volumetric medium. The heating system 100 includes a power control system 104 connected to electrodes 116 and 118. The electrodes 116 and 118 are connected to a target region of the volumetric medium 102 (for example, to a part of the wing of an aircraft). The power control system 104 generates an alternating current (for example, with a frequency of 1 kHz or higher) in a closed circuit along a wire (or path, or cable) 106, through the volumetric medium 102, and finally along a wire (or return path) 108. The direction 112 of current flow through the wires is shown by a dotted arrow.

In some embodiments, the heating system 100 may include, without limitation, a power management system 104, electrodes 116 and 118, and special cables (e.g., wires 108 and 106). In some embodiments, the heating system is configured to be connected to the electrodes 116 and 118. In some embodiments, the heating system is configured to be connected to the special cables (e.g., 108 or 116). In some embodiments, the power management system 104 may include, without limitation, a signal generation unit, a power source, a signal conversion unit, an impedance adjustment circuit, a control unit, and sensors, the specific configurations of which are described in more detail below. As described in detail below, in some embodiments, the impedance adjustment circuit is an impedance matching circuit.

In some embodiments, the electrodes 116 and 118 are contact electrodes. For example, the electrodes 116 and 118 are physically connected to the volumetric medium 102 to supply an electric current from the power management system 104 to the volumetric medium. In some embodiments, the electrodes 116 and 118 can be connected to the volumetric medium 102, but at the same time are electrically isolated from the volumetric medium 102. For example, in such embodiments, the electrodes 116 and 118 can be an input and an output of an inductor coil located near the volumetric medium 102 to induce a current in the volumetric medium 102 due to a magnetic field.

The power management system 104 is configured to supply a current with a sufficiently high frequency (for example, above 1 kHz) to limit the current flow in the z direction between the electrodes 116 and 118 by adjusting the skin effect, which results in a higher resistance of the bulk medium 102. For example, the power management system 104 is configured to provide an alternating current with a frequency of 1 kHz to 300 GHz. In some embodiments, the current frequency is from 10 kHz to 30 GHz. In some embodiments, the current frequency is from 100 kHz to 450 MHz. In some embodiments, the current frequency is in the range of 1 MHz to 50 MHz, 100 MHz to 150 MHz, 200 MHz to 300 MHz, 400 MHz to 500 MHz, or 800 MHz to 1 GHz.

In some embodiments, the return path 108 is located in close proximity to the surface of the bulk medium 102. The proximity of the return path 108 to the surface of the bulk medium can be used to adjust the proximity effect for the current flowing between the electrodes 116 and 118 and, thus, additionally limit the current and increase the heating of the bulk medium. In order to use the proximity effect for the purpose of forming the current flowing between the electrodes 116 and 118, it is not necessary to use the return path 108 of the current from the heating system circuit itself. In some embodiments, another current path 122 (for example, from another circuit) can be located in close proximity (for example, at a distance 120a) to the bulk medium 102. For example, when the distance 120 or 120a from the current path 108 or 122 to the bulk medium 102 is sufficiently small, the proximity effect can be used to additionally limit the passage of current through the bulk medium.

For example, to create a proximity effect, the distance 120 (or 120a) between the volumetric medium and the path 108 (or 122) may be less than 1 m, or less than 50 cm, or less than 10 cm. If it is possible to provide smaller distances taking into account design constraints (for example, if in the case of an aircraft wing as a volumetric medium, the rib or spar of the aircraft is not on the return path 108/122), the distance 120 (or 120a) may be less than 25 cm or less than 10 cm.

The volumetric medium 102 may include materials such as, but not limited to, aluminum, metal alloys, carbon fiber composites, copper, silver, titanium, or steel. For example, the volumetric medium may be any part of an aircraft airframe (e.g., the outer shell or surface of an aircraft, also known as the "skin" of an aircraft), such as a fuselage, wings, landing gear, tail unit, etc.

The electrodes (116 and 118) may include materials such as, but not limited to, aluminum, silver, copper, their alloys, or other conductive materials. In some embodiments, the electrode material has at least the same electrical conductivity as the bulk medium 102. In some embodiments, the electrodes 116 and 118 may be located in electrode matrices. The electrodes may be connected to the bulk medium in various ways, for example, they may be connected to the upper or lower surface of the medium, or may be embedded in the medium.

The heating system 100 is configured to provide an effective resistance in the volumetric medium 102 by forming a current density passing through the medium. In other words, in the case of an airplane, an existing airframe will be used as part of the electric circuit of the heating system. The heating system 100 provides a current density by adjusting the skin effect, the proximity effect, or a combination of both to increase the effective resistance of the volumetric medium 102 along the current path between the electrodes 116 and 118. In some cases, the proximity effect is also used to direct the current path, for example, as shown in Fig. 4D, to heat the desired sections of the volumetric medium. The section of the volumetric medium to be heated may be referred to as a "heating target location" or a "target location".

In some embodiments, alternating current with a frequency of 1 kHz or higher may be passed directly through the airframe. As a result, Joule heating will occur in the airframe area near the surface through which the current passes. In addition, the heat generated by the current passing will be distributed throughout the entire volumetric medium 102 by conduction.

Referring to Fig. 2A-2B, the heating system 100 provides a current density in the middle target region 102 by using the skin effect. As in Fig. 1, an alternating current (in the direction 212) is supplied through the electrodes 116 and 118 through the target region of the volumetric medium 102. Fig. 2A is a schematic illustration illustrating a profile (e.g., a side view) of the current density 202 through the target region of the volumetric medium 102 without the skin effect (e.g., with a current frequency of less than 1 kHz). The current flows in the y direction (212), with most of the current flowing in the volume of the medium 102 indicated by the arrows. For example, the current has a depth 206 of about 2 mm, for example, almost through the entire thickness of the volumetric medium. Thus, Fig. 2A shows the operation of the system 100 with little or no current density formation due to the skin effect.

Fig. 2B is a schematic illustration of a current density profile 202 obtained by applying an alternating current of a higher frequency (e.g., above 1 kHz) through the electrodes. Fig. 2B shows the operation of the system 100 in forming the current density due to the skin effect. For example, due to the skin effect created during the operation of the heating system 100 at a high frequency, the depth of the current density 202 flowing through the bulk medium 102 is limited in the z direction to a narrow region near the surface of the bulk medium 102. In addition, the effective resistance of the bulk medium 102 in the region of the current flow is significantly increased, so that Joule heating can be performed in this region without overheating the rest of the circuit (e.g., wires, a power source, an inverter, a control circuit, electrodes). The effective resistance of the bulk medium to alternating current in the target region can be greater than the resistance of the bulk medium to direct current. For example, the effective resistance can be two or more orders of magnitude higher than the DC resistance of the bulk medium.

Fig. 3 is a graph showing the concentration of the current density (y-axis, normalized to 1) in the depth of the material (x-axis, normalized to 1) as a function of the applied alternating current due to the skin effect. The current density decreases exponentially with the thickness (z-direction) of the medium. As the frequency increases from 1 kHz to 10 MHz, the current density becomes more concentrated near the surface of the bulk medium. Thus, the higher the frequency, the more pronounced this decrease. In other words, the skin effect limits the current density by causing the current to pass through a thin layer near the surface of the bulk medium. Consequently, Joule heating will also occur in this layer.

Fig. 4A is a schematic side view of a system 400 for using the proximity effect to further limit the current density. As in Fig. 1, electrodes 116 and 118 are attached to a volumetric medium 102 (e.g., a target area of the airframe) and supply an alternating current signal (e.g., with a frequency greater than 1 kHz) to create a current density 410 (or path) with a direction 412 through the medium. A return path 108 is located at a distance 120 from the current path 410 (or density) in the medium and has a direction 112 different from the direction 412. In some embodiments, the return path 108 is electrically isolated from the volumetric medium 102. For example, the return path 108 can be a wire or cable located at a distance 120 from the volumetric medium 102. The return path 108 can be a wire or cable that completes the circuit of the system 400.

If the return path 108 is located close enough to the current path 410 (for example, at a distance of less than 50 cm), the alternating current in the return path 108 limits the current in the current path 410 in the directions and across the path of current flow in the current path 410. In other words, placing the return path 108 close enough to the current path 410 results in limiting the cross-sectional area of the current flow in the current path 410. For example, with reference to Fig. 4A-4C, the current is limited in two directions (for example, in the x direction and the z direction, as shown in the figure) between the electrodes 116 and 118. For example, as shown in Fig. 4D, the proximity effect limits the current density 410 either in the x direction or in the y direction depending on the direction of current flow. For example, if the current flows in the x direction, the proximity effect limits the current in the y direction. For example, the proximity effect predominantly limits the current across the direction of current flow, while the skin effect predominantly limits the current density in the depth of the volumetric medium (e.g., in the z direction, as shown in Figs. 2A and 2B). In some cases, the proximity effect may also complement the limitation of the current density in the depth (e.g., in the z direction) of the volumetric medium 102, for example, by enhancing the skin effect in embodiments that use both the skin effect and the proximity effect. In some embodiments, the proximity effect may also be used to determine the direction of current flow through the volumetric medium (e.g., the route along which the current passes through the volumetric medium 102).

Fig. 4B-C are exemplary schematic illustrations of a system 400 as viewed from above. Electrodes 116 and 118 are attached to a target region of a volumetric medium 102 and pass an alternating current signal (e.g., with a frequency greater than 1 kHz) to create a current density 410 (or path) with a direction 412 through the medium. A return path 108 is located in a different x-y plane (dashed line) than the plane of the current path 410 (or density) in the volumetric medium 102. In some embodiments, the current flow in the return path 108 is in a direction 112 that is different from the direction 412 of the current flow in the current path 410 through the volumetric medium 102. For example, in some embodiments, the direction 112 of the current flow in the return path 108 is opposite to the direction 412 of the current flow in the current path 410. If the distance 120 from the return path 108 to the current path 412 is small enough (for example, less than 50 cm), the current flowing between the electrodes 116 and 118 in the volumetric medium 102 will be concentrated near the return path wire (for example, narrowed in the y direction and the z direction) due to the proximity effect, as shown in Fig. 4C. The greater the distance from the return path 108 to the volumetric medium 102, the less the current path 412 in the volumetric medium 102 is limited, as shown in Fig. 4B.

Fig. 4D is an exemplary schematic diagram of another embodiment of system 450, viewed from above. As in the previous system 100, electrodes 116 and 118 are attached to a target region of volumetric medium 102. Return path 108 is located near volumetric medium 102 and in an x-y plane different from the plane of current path 410 in volumetric medium 102. The illustrated embodiment demonstrates how return path 108 (or another separate current path) can be used to form a current path 410 through volumetric medium 102. For example, by placing a second current path (e.g., a current-carrying wire or cable, such as return path 108) near volumetric medium 102, the proximity effect can be used both to limit the width of the current density across the direction of current flow and to form the current path 410 in volumetric medium 102. In Fig. 4D also shows that the proximity effect limits the current density along the current path 410 across the direction of current flow. For example, in Fig. 4D, the current density along the current path 410 is limited in a direction substantially perpendicular to the direction of current flow in each segment of the path 410, and the current path 410 in the volumetric medium 102 corresponds to the shape of the return path 108. In particular, in section A of the current path 410, the current is directed such that it flows in the x direction, and the current density is limited in the y direction and the z direction. In section B of the current path 410, the current is directed such that it flows in the y direction, and the current density is limited in the x direction and the z direction.

The ability to create a more complex current path geometry using the proximity effect, as shown in Fig. 4D, can have several advantages. First, such a path geometry can be used to increase the effective length/path of the current. As described above, increasing the path length leads to an increase in resistance and, therefore, to an increase in Joule heating. Second, the current path geometry can be designed to direct the current to strategic locations for heating. Third, the current path geometry can be used to create areas of increased heating (e.g., hot spots) at sharp corners of the current path.

Due to the combination of the proximity effect and the skin effect, the effective resistance of the bulk medium to alternating current in the target region can be greater than the resistance of the bulk medium to direct current. For example, the effective resistance can be two or more orders of magnitude higher than the resistance of the bulk medium to direct current.

Fig. 5A-B show the results of graphical modeling illustrating the increased concentration of the current density in the target region of the volume conductor 102 near the second conductor/path 108 as a function of the distance 120 between the conductors due to the proximity effect. The current in the volume conductor and the second path is sufficient to create the proximity effect (e.g., a frequency above 1 kHz or 10 MHz) as the distance 120 decreases. For example, when the distance 120 is 20 cm, the current density 410 remains approximately the same in the x-y plane, as shown in Fig. 5A. As the distance 120 decreases to 2 cm, as shown in Fig. 5B, the proximity effect causes a "concentration" or "confinement" of the current 410 around the return path 108 in the x-z plane. This occurs because the majority of the current 410 is concentrated in a narrow strip along the bulk conductor and follows the path of the second conductor (108) (e.g., the return path or other current-carrying wires). In other words, the current 410 follows the path of least inductance, rather than being distributed uniformly throughout the bulk medium.

In some embodiments, a wire other than the return path 108, shown as path 122 in Fig. 1, is used to create the proximity effect. In this case, the current fluctuations in this wire may be controlled by the same system (for example, the power management system 104) as the paths 106 and 108, or not. In this case, the proximity effect of the wire 122 will depend on the distance from the wire 112 to the current path 412 in the bulk conductor. As in the case of the return path 108, it may be necessary for the wire 122 to be quite close (for example, at a distance of less than 50 cm) to the path 412.

In general, the power management system 104 supplies current to the volumetric medium 102 via electrodes (e.g., 116 and 118) and special electrical conductors (e.g., special wires or special cables) to form a closed circuit (see Fig. 1). These three components will be discussed in more detail below.

In some embodiments, the electrodes 116 and 118 include an array of input and output electrodes, as shown in Fig. 6A. The electrode system 600 includes three input electrodes 116 (1) - (3) forming an electrode array 116, and three output electrodes 118 (1) - (3) forming an electrode array 118 and forming adjacent current paths 410 in the volumetric medium. The proximity effect due to the current 112 in the return wires 108 limits the current density 410 in the volumetric medium, as described above.

In general, electrodes of different geometries can be used to achieve the desired heating in the target regions of the volumetric medium 102. For example, with reference to Fig. 6B, the system 610 shows two electrode devices 116 and 118 used to supply current through the target region of the volumetric medium 102 (with input/output wires 106 and 108). The arrangement 116 and 118 of the electrodes can be an array of one or more electrodes, as shown in Fig. 6A. Figs. 6C-D are schematic illustrations of other configurations 620 and 630 of the electrodes, respectively, for heating the target region(s) 120, for example, on the wing of an aircraft. The electrode arrangements designated by reference numerals 116, 118 and 640 can be single electrodes or an array of one or more electrodes, as shown in Fig. 6A. Additional information on the shape and design of the electrodes is provided below.

In some embodiments, the volumetric medium is the skin of the aircraft, and the target areas of heating include, but are not limited to: wings, fuselage, vertical stabilizers, horizontal stabilizers, windows, winglets, windshield, control surfaces (flaps, ailerons, rudder, elevator, air brakes, etc.), nose section/nose cone, landing gear, landing gear brakes, landing gear doors, engines and engine nacelles, air conditioning inlets and outlets, fuel tank vents, air pressure probes, static pressure probes and other antennas, sensors and external warning lights, operational flaps. In other words, in some cases, the proposed technology may provide for placing electrodes on the interior of the airframe in one or more of the configurations shown in Fig. 6A-D. In some embodiments, the heating system 100 will provide Joule heating in portions of the target area, and then the thermal conductivity of the material may provide more "distributed" heating.

In general, the power management system 104 includes a signal generation system configured to generate a high-frequency (for example, with a frequency above 1 kHz) alternating electric current signal and transmit it through the above-mentioned target region of the volumetric medium 102. In some embodiments, in which the impedance of the target region is small (in some cases significantly less than 1 ohm), the signal generation system is configured to generate and maintain the necessary current level to perform Joule heating of the target region. In some cases, since the impedances of other parts of the system (for example, electrical conductors or wires along which the signal is transmitted) are above zero, the high current passing through these parts will perform unwanted Joule heating outside the target region. For this reason, in some embodiments, the signal generation system is designed in such a way that the high current is supplied only near the target region.

In some embodiments, some or all of the elements/blocks of the signal generation system, as well as the conductive blocks/cables connecting them, are designed to minimize unwanted power losses typically encountered when transmitting high current and high frequency electromagnetic signals.

In some embodiments, the signal generation system may be powered by existing power sources (e.g., existing electrical buses of the aircraft). In some embodiments, the system uses a special battery or a special power source that is part of the system. For example, such special power sources may include, but are not limited to: fuel-powered electrical generators, solar-powered electrical generators, wind-powered electrical generators, gas-powered electrical generators, etc. In some embodiments, the signal generation system may be located in a circuit between the power source (e.g., an existing electrical bus, a special battery, a special power source) and the target area.

In addition, in some embodiments, the signal generation system may include control circuits and devices that exist as independent units and/or are integrated into a plurality of other units that are part of the signal generation system.

In some embodiments, the heating system 100 is used to heat several separate target areas. In such a case, each element or block of the heating system (for example, the signal conversion block, the impedance adjustment circuit, etc.) can either be centralized for the entire system, or can be distributed as a separate block or several blocks based on the target area or a group of target areas. Centralization or distribution configurations, among other things, can be used to improve the functionality of the system, increase energy efficiency, reduce cost, comply with regulatory documents, reduce weight, size and complexity. For example, in some embodiments, the signal conversion block is centralized, while the impedance adjustment circuit is distributed based on one or more blocks per target area. In some embodiments, the signal conversion block is only partially centralized with a centralized sub-block for converting to standardized power, but the AC generation sub-block is distributed based on one or more sub-blocks per target area or a group of target areas. In some embodiments, the signal conversion unit is fully distributed, with each of its sub-units distributed at the rate of one or more sub-units per target area or group of target areas.

In some embodiments, the power management system 104 continuously supplies power to the target area 102 until the heating/deicing/anti-icing operation is completed. In some embodiments, the system can turn on and off the power supply (e.g., using a control unit) in an improved/efficient manner to achieve the desired heat generation and distribution in the conductive material 102. For example, when the system is turned on, heat is generated in specific locations of the target area and is transferred across the target area, "spreading" to the rest of the target area. When the system is turned off, the generated heat continues to spread across the target area.

In some embodiments, as an improvement, the system may include different power levels for the on state and cycle between the off state and different power levels. In some embodiments, specific power levels may be achieved by smoothly increasing/decreasing the power, as opposed to a single step increase or decrease in power. Such pulsed modes of operation of the power management system may either be completely pre-programmed when setting up the system, or may be changed and dynamically improved based on feedback loops that form part of the control unit of the system, as described in detail below.

In some embodiments, in which the heating system includes several target areas, the pulsed power supply mode described above may be used asynchronously across all target areas, so that all target areas will be heated in a required amount of time, while both the total average and total instantaneous power levels will remain below a specified threshold. For example, in the case of an aircraft anti-icing system that provides for heating both wings, the fuselage, and the horizontal and vertical stabilizers, such a staged power supply mode may be designed so that the system is turned on for only one target area at a time. In some embodiments, the staged power supply mode may be as follows: turning on the system for the left wing, then for the fuselage, then for the right wing, then for the vertical stabilizer and then for the horizontal stabilizer.

In some embodiments, improved synchronization may be used at each stage to achieve the desired heating, average power, instantaneous power level, and acceptable heat distribution. In some embodiments, similar to the above-described mode, any subset of target areas may be heated at a given time.

In some embodiments, one or more units or elements specified as part of the heating system design have a casing. Such a casing may be designed for one unit or for any combination of units. In some embodiments, the casings are designed in accordance with environmental impact certification standards. For example, the casings may be designed in accordance with criteria such as non-flammability, protection from precipitation, fastening and design that provide protection from external shocks and vibrations, electrical insulation, protection from external electromagnetic interference and shielding of external electromagnetic interference radiation in closed circuits, as well as thermal relief.

In some embodiments, some housings may be designed to use the structure of the heated object (for example, a bulk conductive material) as a heat sink. For example, one or more blocks of the heating system may be placed in metal or conductive structures installed in such a way that they have a high thermal conductivity with respect to the bulk medium on which they are located. One possible advantage of this design is heating the bulk medium and also providing the necessary cooling of the electronic equipment. Another possible advantage of this design is a reduction in the mass of the heating system (or device) by eliminating the need to provide a separate heat sink to dissipate losses. In some embodiments, the target areas may be used as part of the heat sinks of the blocks of the heating system. Such use may increase the efficiency of the heating system, since the circuits of the heating system inevitably create heat losses that can be transferred to the target areas for their heating.

In some embodiments, adhesives or fasteners of different types may be used to attach the housing to the bulk medium. For example, one adhesive used primarily to maintain mechanical rigidity may be used to hold the housing in place, while another adhesive (or layer) may be used to provide a path with lower thermal impedance to perform the heat-dissipating function of the housing.

In some embodiments, one or more units of the heating system may be configured to determine one or more measurements, including, but not limited to, voltage, current, temperature, forward power and reflected power measured in the unit circuits, surrounding cables, other units or target areas. In some embodiments, such measurements may then be used to monitor the operating state of the unit(s) and control their operation (using a feedback mechanism), including on/off, output signal levels and internal control of switching and adjustable parts to improve efficiency (more details on control of switching and adjustable parts in the dynamic adjustment circuit are provided below). Adjustable parameters may include power to load and/or current to load ratio, voltage control in the adjustment circuit and other relevant signals.

In some embodiments, the above-described measurements used within the feedback loops may also include special icing sensors that may be installed at or near target areas. Such sensors may be used, for example, to inform the heating system and/or the user of the completion status of deicing, and may also provide input data for adjusting power levels during the deicing and icing prevention stages. In some embodiments, icing sensors may also be used to detect system failures and/or the need for maintenance.

In some embodiments, the heating system may include a protocol converter control unit (or "control unit" or "sub-control unit") that receives input data from a user (which may be a pilot or co-pilot in the case of an aircraft anti-icing system) and/or system transmitters and outputs control signals to other units. In some embodiments, the user input data may include, but is not limited to, an on/off state, an ice removal/anti-icing/off state, target temperatures for target areas, and a target output power for target areas. In some embodiments, the sensor input data may include, but is not limited to, voltage, current, temperature, forward power and reflected power, impedance, ice transmitter data, a safety latch, various aircraft logic units, information from avionics, and other data. In some embodiments, the protocol converter control unit is centralized for the entire system. In some embodiments, it is distributed at the rate of one protocol converter control unit per target area or group of target areas.

In some embodiments, the user input data may be transmitted to the control unit either by wire (e.g., using data transmission standards such as ARINC 429) or wireless (e.g., using a Bluetooth or low energy Wi-Fi connection). In some embodiments, the user input device may be either integrated into the heating system (e.g., integrated into on-screen controls on the flight deck in the case of an aircraft de-icing system) or may be a separate device such as a touchscreen tablet (e.g., a separate tablet mounted on the flight deck or a dedicated application installed on the pilot's touchscreen tablet in the case of an aircraft de-icing system).

In some embodiments, the power management system 104 includes a signal conversion unit or circuit that converts a signal from existing electrical buses or a special battery, or any other power source of the heating system into the necessary high-frequency AC signal for generating current in the volumetric medium. For example, in the case of an aircraft, the signal conversion unit may receive DC power available from the aircraft electrical bus and convert it into the necessary high-frequency AC signal. In another example of an aircraft, the signal conversion unit may receive power available from the aircraft electrical bus in the form of an AC signal and convert it into the necessary high-frequency AC signal. In some embodiments, the signal conversion unit may receive DC power available from a special battery or from any special power source (for example, forming part of the heating system) and convert it into the necessary high-frequency AC signal. In some embodiments, the special batteries or power sources may be integrated into the same housing and/or circuit board as the signal conversion unit.

Fig. 7 is a schematic diagram of an example signal conversion unit 700 for the power management system 104, including a main subunit 710 for converting to standardized power and a main subunit 720 for generating alternating current, which precede another circuit 730 in the rest of the device 100. The power management system 104 can be powered from existing power sources, as shown in Fig. 7.

Fig. 8 is a schematic diagram of an example signal conversion unit 800 for power management system 104, including a standardized power conversion subunit 810, an AC generation subunit 820, and a control subunit 830.

In some embodiments, the standardized power conversion subunit receives power from existing power sources or from a heating system battery and converts it into a standardized input signal, such as 250 V DC, to improve the operation of the AC generation subunit and to improve the power transmission efficiency of the signal conversion unit.

In some embodiments, in which existing electrical buses supply power in the form of a 400 Hz, 115 V AC signal to the power standardization subunit, the power standardization subunit may include a flyback converter with an output filter, such as a common mode choke, that prevents electromagnetic interference from entering or damaging the AC generation subunit. Fig. 9A is a schematic illustration of an example power standardization subunit 900 that includes a flyback converter 910 and a common mode choke 920. Fig. 9B is a schematic illustration of an example flyback converter 910.

In some embodiments, the power standardization subunit is a bridge rectifier that converts AC power from existing power sources to any desired DC voltage. In some embodiments, the power standardization subunit receives DC power from a battery or existing power sources (e.g., 28 VDC, which is typical for an aircraft) and converts it to another DC voltage or AC voltage. For example, DC voltage conversion may be preferred for powering control units and heating system components, in which case possible voltage levels may include ±3.3 V, ±5 V, and/or ±12 V. Finally, in some embodiments, a power factor correction stage may be included in the design of the power standardization subunit depending on the power source. In some embodiments, the power factor correction may serve to correct a non-linear load of the power source, which may be necessary. Active and passive power factor correction stages may be used.

In some embodiments, the AC generation subunit uses the input power from the standardized power conversion subunit and converts it into the desired high-frequency AC signal. In some embodiments, the AC generation subunit is designed to improve the efficiency of power transmission by the signal conversion unit. In some embodiments, the AC generation subunit includes a power amplifier or an AC generator/RF generator.

In some embodiments, the main power gain stage of the power amplifier is either "linear" or "switching". The relevant tradeoffs between these two architectures may include efficiency, power handling, and linearity. Examples of linear amplifiers may include class A, class B, and class C amplifiers. Examples of switching amplifiers may include class D, class E, and class F amplifiers. In some embodiments, linear amplifiers have high linearity and low efficiency compared to switching amplifiers. Low efficiency may mean more complex thermal management, higher component requirements, etc. Low linearity may mean increased harmonic content, potentially causing regulatory compliance issues, lower efficiency, more complex physical and electrical layout design, etc.

In some embodiments, the AC current generation subunit includes a full-bridge class D amplifier. For example, the amplifier design uses dual MOSFETs fed by a gate driver and a temperature-compensated crystal oscillator generating the desired frequency. Fig. 10A is a schematic diagram of an example AC current generation subunit 1000 that includes a dual MOSFET class D amplifier 1010, a temperature-compensated crystal oscillator 1020, and a gate driver 1030. Fig. 10B is a theoretical schematic diagram of an example class D amplifier using dual MOSFETs. In some embodiments, the full-bridge architecture may provide differential (balanced) transmission capability and four times the output power for a given bus voltage level at a given load compared to a half-bridge architecture. Differential transmission may also be important in terms of meeting emission standards under balanced load conditions, as presented by the intended wing design. Additionally, in some implementations, Class D architectures may have higher switch utilization than other switching architectures.

In some implementations of a single-frequency Class D architecture, many input parameters can be changed to achieve improved output parameters. An example of an input parameter includes dead time. Examples of output parameters include efficiency, component peak voltages, etc.

In some embodiments, class D architectures may have high switch utilization and all-silicon component implementations, making them suitable for potential special-purpose integrated circuit development. Such designs may implement a system-on-chip in which all control components and power electronics are either on a single chip or in a multi-chip package. In some embodiments, class D architectures have distributed modules that contain systems-on-chip and support circuits attached to various, distributed locations on a given aircraft component.

Other implementations use other switching designs, such as single switch architectures, such as Class E or Class F. In some implementations, such architectures may be implemented at higher switching frequencies, making the high-side gate driver difficult or impossible to implement. In some implementations, single switch architectures may be used in place of Class D implementations as frequency increases due to potential limitations of Class D implementations at these frequencies.

In some embodiments, harmonic reduction and elimination technologies may be used with switching amplifiers to mitigate the negative effects of nonlinear distortion inherent in some switching architectures. For example, fundamental duty cycle variation, blanking pulses, and other technologies may be used to eliminate harmonics during signal generation.

In some embodiments, the AC power generation subunit includes transistors, including silicon MOSFETs. In some embodiments, the transistors are Gallium Nitride (GaN) MOSFETs. In some embodiments, GaN-based transistors have the following preferred properties: on-resistance, gate charge when turned on, and reverse recovery charge. In some embodiments, GaN is suitable for higher frequencies.

In some embodiments, the standardized power conversion subunit further includes a low-power conversion stage, such as a linear regulator, for receiving power from existing power sources and converting it into a suitable power input signal for elements that drive the AC generation subunit, such as gate drivers or crystal oscillators. Fig. 10C is a schematic illustration of an example AC generation subunit 1050 that includes a class D amplifier 1010 with dual MOSFETs, a temperature-compensated crystal oscillator 1020, a gate driver 1030, and a low-power conversion stage 1060.

In some embodiments, the AC generation subunit is located near the target area. A possible advantage of this design is to limit the losses and emissions that occur when transmitting AC from the AC generation subunit through the regulation circuit to the target area. In some embodiments, the standardized power conversion subunit may be located near the AC generation subunit or near an existing power source or a special battery. When the standardized power conversion subunit is located closer to the AC generation subunit, it can be combined with the AC generation subunit, which potentially reduces the number of modules in the system and its complexity. When the standardized power conversion subunit is located closer to the existing power source or a special battery, it can be designed to improve power transmission (including increased efficiency and reduced electromagnetic interference) from the power source or battery to the AC generation subunit. For example, when an existing power source provides power at a frequency of 400 Hz and a voltage of 115 V AC, the power conversion subunit may include an AC-to-DC converter that converts the power source voltage to 250 V DC, which reduces electromagnetic interference that may be caused by the AC current and improves efficiency by increasing the voltage and decreasing the amount of current transferred from the power conversion subunit to the AC generation subunit.

In some embodiments, the control subunit controls the state of the signal conversion unit, on/off, output power, frequency and other parameters based on the relevant input data available in the application area for which the device (heating system) is designed, by outputting control signals to other signal conversion subunits, including a standardized power conversion subunit, as well as drivers of the alternating current generation subunit. In the example of a heating system for deicing and preventing icing of an aircraft, in some embodiments, the data input may include manual data input by the pilot via a switch on the flight deck, the temperature of the temperature sensors inside and outside the airframe, the status of the landing gear compression from the safety latch, various logical units of the aircraft, information from the radio-electronic equipment, feedback from the device (heating system) itself, as well as other data. In some embodiments, the control subunit includes a microcontroller supervisor fed from a low-power conversion stage, such as a linear regulator that receives power from existing power sources and converts it into a suitable power input signal, and outputs control signals to a standardized power conversion subunit and an AC generation subunit. Fig. 11 is a schematic illustration of an example control subunit 1100 that includes a microcontroller 1110 and a low-power conversion stage 1120.

In some embodiments, for example, in the case of a modernized anti-icing heating system of an aircraft, the signal conversion unit may be installed near accessible electrical buses in a centralized location. This may reduce the complexity of installation, installation time and costs of this unit. In some embodiments, the signal conversion unit is decentralized and installed closer to the target areas. This may reduce the distance that the AC signal must travel between the signal conversion unit and the target areas, which may potentially reduce costs associated with shielding the signal from electromagnetic interference and requirements for the cable through which such an AC signal is transmitted.

In some embodiments, the heating system has an impedance control circuit configured to adjust the output impedance of the heating system to the desired levels. For example, the impedance control circuit can be configured to adjust the output impedance of the heating system in accordance with the input impedance of the bulk medium that is to be heated. For example, the impedance control circuit can be configured to adjust the impedances between the output of the heating system and the input of the bulk medium so that they are in a desired range relative to each other. In some embodiments, the impedance control circuit is configured to adjust the output impedance of the heating system in accordance with the impedance of the bulk medium. In other words, the matching circuit is configured to match the output impedance of the signal conversion unit ("source") with the impedance of the target region ("load") within reasonable technical tolerances. In some embodiments, matching the impedances of the source and load includes adjusting the impedance of the source of the heating system so that it is complex-conjugate with the impedance of the bulk medium. In some embodiments, the impedance adjustment circuit is adjusted so that the output impedance of the heating system is within 10-30% of the impedance of the bulk medium to be heated.

Fig. 12 is a conceptual schematic illustration of a control circuit 1200 between a source 1210 and a load 1220. Fig. 12 shows a control circuit that receives input power from a signal conditioning unit ("source") through an input port whose impedance is adjusted in accordance with an output signal of the signal conditioning unit, and outputs power to target areas ("load") through an output port whose impedance is adjusted in accordance with the target areas.

In general, in the case of an AC signal, when the output impedance of the source does not match the impedance of the load, a portion of the signal transmitted from the source to the load is reflected back to the source rather than passing through the load. In some embodiments, an impedance adjustment circuit can provide a number of benefits by preventing signal reflection and the buildup of a voltage standing wave, including:

- voltage reduction in case of risk of heating and electric arcing

- increasing the efficiency of the heating system

- reduction of the total output power required from the signal conversion unit and, consequently, reduction of the size, weight and cost of the signal conversion unit

- reducing the load on system components

- increasing reliability

- reduction of temperature gradients in cable wiring and volumetric environment.

In some embodiments, the output impedance of the signal conversion unit is higher than the impedance of the target areas. In this case, the control circuit converts the relatively high-voltage, low-current power supply from the signal conversion unit into a relatively low-voltage, high-current power supply supplied to the target areas. In embodiments, this means that the high current is supplied only after the control circuit and thus closer to the target area, which reduces the Joule losses in the rest of the signal conversion unit and increases the overall efficiency of the heating system.

In various embodiments, the control circuit may be either centralized or distributed across all target areas. Distributing the control circuit may allow the cabling to be used as a filter, potentially reducing peak voltage, peak current, and/or temperature effects on any given component. Distributing may also add modularity to the system design, which may improve ease of maintenance/replacement of parts. In addition, distributing may potentially eliminate sensitive equipment and/or hazardous areas, such as fuel tanks, from the system.

A distributed impedance adjustment circuit, such as an impedance matching circuit located at the input of the connection strip 1900, can facilitate local implementation of distributed monitoring for each connection strip, even in embodiments in which the power management system 104 supplies power to a plurality of connection strips. It can also provide means for various localized capabilities, including capabilities for turning on or off the connection strip 1900, and means for transmitting information to the power management system 104. Such transmission can be provided either by separate communication cables or by coding the power cable (for example, by power cables connected to the connection strips 1900) in order to reduce weight and prevent cable entanglement.

For example, the distributed impedance control circuit can initiate a special impedance state that can be detected by the power management system 104 based on the use of an intentional impedance change to encode signals to be sent back along the power line, such as by encoding a type of digital communication, or by encoding an analog or threshold level. As another example, the distributed impedance control circuit is configured to add an additional data signal (in addition to the power signal for heating) to the power cable. Alternatively or additionally, one or more units or elements indicated as part of the heating system can transmit information by wireless means.

In some embodiments, the control circuit additionally supports fault indication. In these embodiments, the heating system may include local fault sensors, which, as will be described in more detail below in the section "Control and measurement", may be turned on or off in the event of faults or failures in the heating system. For example, local fault sensors may be located on the connecting strips 1900. The control circuit may include a controller that supports work with a look-up table, in which various types of faults of specific parts and sections of the heating system are defined, as well as various impedance values corresponding to the types of faults. Then, the control circuit may be configured to adjust its input impedance, determined by the power management system, to specific values in such a way as to indicate specific types of faults or failures that may be present.

In addition, in some embodiments, the control circuit may be balanced by including additional capacitive components and grounding the midpoints of symmetry in the circuit. When driven from a fully differential source, balancing the circuit may provide a high level of common mode rejection and better noise immunity. In some embodiments, such balance is not achieved and the end of the return path of the control circuit is at the ground of the circuit.

In general, in some embodiments, the adjustment circuits may include passive electronic components arranged in accordance with certain configurations of structural blocks. For example, these configurations of structural blocks may include transformers, L-shaped circuits, U-shaped circuits, T-shaped circuits, and other configurations. Figs. 13A-D are schematic illustrations of exemplary structural blocks of an impedance adjustment circuit.

In some embodiments, the heating system control circuit includes a passive control subunit. Fig. 14 is a schematic illustration of an example control circuit block 1400 that includes a passive control subunit 1410. In some embodiments, the passive control subunit may include one or more configurations of the structural blocks described above, as well as other configurations assembled together. In some embodiments, the passive electronic components of the passive control subunit are selected to have high quality indicators, for example, to improve the efficiency of the circuit.

In some embodiments, the heating system control circuit may be designed to have a high figure of merit or a low figure of merit. Control circuits with a high figure of merit may be used to filter harmonics in the signal. Filtering may be preferable in the design of a switching amplifier, since in this case the harmonic content may be higher than in the case of a linear amplifier. However, circuits with a high figure of merit may be more sensitive to component tolerances, operational changes in external conditions, assembly variations, and any other changes in the system. Thus, the use of systems with a high figure of merit may entail practical problems in the implementation of the systems. For example, in the case of an aircraft wing anti-icing system, if the system has a high figure of merit, the impedance control circuit settings may become misadjusted due to minor disturbances (e.g., flap movements), which causes a risk of failure. Reducing harmonic content outside the fundamental excitation frequency may be desirable for formal certification purposes as well as for practical design issues including spurious content in the design, component overstress (either at peak loads or at average loads), control algorithm instability, etc. In some cases, these sensitivity issues can be reduced or even eliminated by using dynamically tuned elements.

In some embodiments, the design of the heating system control circuit may be based on transmission line control concepts. For example, the cabling at the input and/or output of the control circuit may be considered as part of the control circuit. In some embodiments, by selecting the right materials, form factor, dimensions, and length of cables, suitable impedance control may be achieved.

In some embodiments, the heating system control circuit is a dynamic control circuit that includes an active control subunit and a control subunit. Fig. 15A is a schematic diagram of an example control circuit block 1500 that includes an active control subunit 1510 and a control subunit 1520. In some embodiments, the active control subunit includes one or more control circuit configurations under the control of the control subunit. In some embodiments, the passive electronic components of the active control subunit are selected to have high quality characteristics, such as to improve the efficiency of the circuit. In some embodiments, the control subunit receives input data from a signal transmitted and received from target areas (such as forward power, reflected power, or voltage standing wave ratio), and dynamically controls the active control subunit to adjust the impedance setting in real time. For example, such control can be achieved by adjusting elements included in the design of the active control subunit. For example, dynamically tuned elements may include tuned capacitors and/or tuned inductors. Further examples of tuned elements include: point contact diodes, barium strontium titanate capacitors, individual tuning capacitors, varactor diodes, microelectromechanical systems, ferroelectric varactors, ferromagnetic components, yttrium iron garnet filters, etc. Example metrics that may be considered when evaluating such devices include: operating frequency range, DC voltage tuning, control signal linearity tuning, control complexity, capacitance/inductance tuning ratio, tuning speed, figure of merit (Q), switching lifetime, packaging cost, power handling, power consumption, breakdown voltage, linearity, IP3 interception, integration capability, etc.

In some embodiments, the use of a control unit with feedback between the target areas and the control circuit may allow the circuit to adapt to any external changes that may affect the impedance of the target area or the output impedance of the signal conditioning unit, including changes in temperature, the geometric configuration of the target areas, the location of the heating system, the environment of the system and the target areas, and other parameters. In some embodiments, the control circuit further includes a low-power conversion stage, such as a linear regulator, receiving power from existing power sources and converting it into a suitable input power signal for the control subunit. Fig. 15B is a schematic illustration of an example block 1550 of the control circuit, including an active regulation subunit 1510, a low-power conversion stage 1560 and a control subunit 1520.

In some embodiments, special impedance measurements may be performed in target areas for all configurations and environmental conditions covering the spectrum of possible situations when using the heating system. These measurements may allow the development of a dynamic control circuit block adapted to the smallest impedance range that allows optimal impedance control for the entire spectrum of the above situations. In some embodiments, such a design is achieved by using algorithmic optimization or computer modeling to improve the efficiency of the system while reducing the weight, complexity and cost of the control circuit.

In some embodiments, the heating system may use special cables that are specially designed or selected at each stage to improve the efficiency and shielding of the power signal transmitted to the target areas. Fig. 16 is a schematic illustration of cable stages in an example heating system. In various embodiments, the cable stages in the heating system may be designed to include features including cables between the power sources 1620 and the signal conditioning unit 1610 (the first cable stage 1630), cables in the signal conditioning unit between the standardized power conversion subunit 1640 and the alternating current generation subunit 1650 (the second cable stage 1660), cables between the signal conditioning unit 1610 and the control circuit 1670 (the third cable stage 1680), and cables between the control circuit 1670 and the target areas 1690 (the fourth cable stage 1695).

In general, when designing special cables in a heating system, it is important to consider various design features. In some embodiments, it is important to consider thermal features. For example, in some embodiments, the cable connecting the control circuit to the target area (or in some cases passing near the target area and returning to the control circuit) is fixed to provide an increased heat flow from the cable to the target area. This is advantageous if a portion of the heat generated by the current flowing through the cables (which would otherwise be lost) is recovered and transferred to the target area whose task is to generate heat, which increases the efficiency of the system.

In some embodiments, cables may be routed near the target area using fasteners. In such cases, thermal paste with improved thermal conductivity may be used to improve thermal contact by filling air gaps at the interface between the cables, fasteners, and the target area.

In some embodiments, cables are attached directly to the target area. In such cases, to improve thermal contact, an adhesive with higher thermal conductivity may be used to attach the cable to the contact area. In addition, a thermal paste with higher thermal conductivity may be used to fill some or all of the remaining air gaps between the cable and the target area.

In some embodiments, cables with different cross-sectional geometries and form factors may be used, depending on the units, target areas, or power sources to which the cables are connected. In some embodiments, the cable includes only the main conductor with or without a protective jacket (including for electrical insulation and/or protection from the environment, such as corrosion, humidity, extreme temperatures, friction). This configuration may be preferable for parts of the system that will carry a DC signal or that will deliver a signal to the target area.

In some embodiments, the cable is a coaxial cable. The coaxial cable may include a shield that can reduce electromagnetic interference radiation when transmitting an AC signal and can protect against electromagnetic interference surrounding the system when transmitting any signal.

In some embodiments, the cable is a triaxial cable. This design may be advantageous for electromagnetic interference protection and isolation when transmitting any signal, and in particular when transmitting a balanced signal, such as at the output of a balanced embodiment of the control circuit block.

In some embodiments, the cable is a twinaxial cable. This design can have the same advantages as a triaxial cable.

In some embodiments, cables with different cross-sectional geometries may be used depending on the units, target areas, or power sources to which the cables are connected.

In some embodiments, the cable conductor(s) have a circular cross-section. The advantage of this design is the relatively low manufacturing cost (low one-time design costs) in the case of coaxial/triaxial/twinaxial form factors.

In some embodiments, the cable cross-section has a flat and/or rectangular shape. For example, this cross-section may be a preferred cable geometry in the last stage of the system, where the cable delivers current to the target area. In this stage, the rectangular shape may reduce the influence of the proximity effect and the skin effect on the current passing through the cable, which leads to reduced losses and increased efficiency of the system. In addition, such a geometry may reduce the total amount of conductive material in the cable and, therefore, reduce the mass of the system, which is an important aspect in the case of an aircraft anti-icing system.

In some embodiments, depending on the specific input and output current and signals transmitted through the cable, as well as depending on the cross-sectional geometry and other factors, the cross-sectional size may be selected to limit operating temperatures to a certain range (e.g., in accordance with and depending on the materials used to make the cable), and to reduce weight and size.

In some embodiments, different types of cable shielding (and cross-sectional geometries) may be used depending on the units, target areas, or power sources to which the cables are connected.

In some embodiments, the cable is not shielded. This is most advantageous in stages where DC current is carried (and hence lower EMI requirements apply) and where there is no need to provide a return path (e.g., in a later stage of the system in an embodiment where a return current is carried through the target area and a nearby cable supplies this current to the target area).

In some embodiments, single shielding is used. This is preferred, for example, when one layer of shielding is sufficient to meet the cable's EMI/EMC requirements and other environmental requirements.

In some embodiments, double shielding is used. In this case, another shielding layer is added, which, for example, can further reduce the emission of electromagnetic interference and reduce the sensitivity of the cable to electromagnetic interference.

In some embodiments, shielding with three or more layers is used, adding additional shielding layers similar to those indicated above.

In some embodiments, for a given target area, cables supplying current to that area may run along different possible paths.

In some embodiments, the cables simply follow approximately straight paths from one side of the target area to the other. In some cases, these paths may be parallel. In some embodiments, the cables may run diagonally across the target area, crossing each other at various locations in the target area. This, for example, provides for more uniform heat generation across the surface of the target area and allows for the creation of relatively hotter spots at desired locations where the cables cross each other.

In some embodiments, the cables are routed along a zigzag path, a serpentine path, or a path that can be modeled using two-dimensional spline curves. This design allows for increased system efficiency by extending the path along which the current flows through the target area, and thus further increasing the effective resistance. This allows for higher efficiency, lower current, and more stable impedance regulation in the system, for example.

In some embodiments, cable path designs are based on a combination of the above and other options.

In some embodiments, depending on the design, stage and purpose of the cable, different materials may be used in its manufacture.

Depending on local voltage, current, temperature, power, bend radius and wear resistance requirements, and other criteria, cable conductor materials can be selected to improve efficiency, improve electrical conductivity, reduce weight, cost, size and improve thermal performance.

In some embodiments, the conductor material may be copper, silver, aluminum, carbon fiber composite, titanium, or an alloy thereof. In some embodiments, the conductor is made of any of the above materials and coated with other materials, such as a silver coating to improve the conductivity of the conductor shell.

In some embodiments, the conductors may be made of solid materials or may be twisted. For example, in some embodiments, all the cores may be insulated from each other using an insulating coating, such as enamel. For example, to reduce the influence of the skin effect and the proximity effect, litz wire may be used in the cable.

In some embodiments (e.g., in the case of coaxial/triaxial/twinaxial cables), depending on the requirements for local voltage, current, temperature, power, bend radius and durability, as well as other criteria, cable dielectric materials can be selected to improve such parameters as efficiency (e.g., by reducing dielectric losses), weight, cost, flexibility, maximum permissible voltage deviation, maximum permissible power deviation, temperature rating (by withstanding higher temperatures, and/or higher thermal capacity, and/or lower dielectric losses and/or better thermal conductivity of the cable).

In some embodiments in which the control circuit block uses transmission line control, the corresponding cables may use dielectric materials that are also selected to achieve the required impedance levels. Examples of materials include polyethylene and Teflon-based materials, as well as other materials.

In some embodiments, depending on local voltage, current, temperature, power, bend radius, and durability requirements, as well as other criteria, cable jacket materials are selected to improve parameters such as weight, cost, flexibility, maximum allowable voltage deviation, temperature rating, and thermal conductivity with respect to nearby heat sinks (e.g., a target area when used as a heat sink).

In some embodiments, when using transmission line adjustment as part of an adjustment scheme to achieve a target impedance level, in addition to dielectric materials, the length of the cable used to adjust the impedance can be adjusted. For example, a cable that supplies current to a target area is used as part of a transmission line adjustment system, with its length being increased to adjust the impedance and the cable being locally wound so that it takes up less space.

In some embodiments, special fastening technologies may be used to route cables through the system structure. Such technologies may be selected to improve such parameters as installation cost and time, system weight (by reducing the required wire length and fastener weight), and to improve the required electromagnetic effects and heat transfer of cables near the target area.

In some embodiments, the fastening element is selected to reduce the distance between the cable supplying power to the target area and the target area. Such a design can create a more pronounced proximity effect. In some embodiments, in the case of a small distance between the cable and the target area, conventional cable fastening element designs can be selected.

In some embodiments, fasteners are also used to increase thermal conductivity from cables to the target area.

In some embodiments, the fastener materials are selected to reduce the weight and cost of the system. This can be achieved, for example, by using composite materials. In some embodiments in which the fasteners are also used to supply heat to the target area, the materials are also selected to increase thermal conductivity (metals, for example, typically have relatively high thermal conductivity).

In some embodiments, adhesives used to attach fasteners to fastening areas are selected to improve strength and ensure long-term attachment to the target area. The strength of the adhesive is particularly advantageous in the case where the fastening area is relatively small and the mechanical constraints created in the fastening area are relatively high. In addition, in some embodiments in which fasteners are used to conduct heat from a cable to a target area, the adhesive is also selected to improve thermal conductivity.

Finally, in some embodiments in which fasteners are used to conduct heat from a cable to a target area, the air gaps in the area between the cable, fasteners, and target area are filled with a thermal paste having sufficient thermal conductivity to provide improved heat flow from the cable to the target area.

In some embodiments, cables are attached directly to surrounding structures, such as a bulk environment, using an adhesive, which provides better heat transfer from the cable to the structure to which it is attached. Adhesives are selected based on criteria similar to those used for fasteners.

In some embodiments, the cable assembly designs provide for dividing a given cable path into a group of two or more separate branches. This is, for example, advantageous in embodiments in which a single control circuit supplies current to a group of several target areas. In such embodiments, one cable may be the only output of the control circuit and, as it approaches the target areas, the cable may be divided into separate branches, each of which supplies current to the target areas. In some embodiments, such a division may be achieved by dividing a given conductor core into several smaller cores by distributing a subset of the cores to each of the separate branches when the divided cable has a multi-core conductor, or by using a power divider. The power divider may be used to control the amount of current, voltage and power supplied to each of the branches into which the cable is divided.

Similarly, in some embodiments, two or more cables may be connected into a smaller number of cables that combine signals from all of the connected cables. Such a connection may be achieved by connecting specific conductor cores to other cores, by rearranging different subsets of the cores into new multi-core cables, or by using a power combiner (e.g., a device similar to a power divider but used in the opposite manner). A power combiner may be used to control the amount of current, voltage, and power supplied to each of the branches into which the cables have been connected.

In some embodiments, each stage of cables in a heating system has unique cable design features.

In some embodiments, the first stage of the cables is selected so as to ensure efficient transmission of power from the power sources to the subunit for converting into standardized power. In some embodiments, in which the power sources deliver direct electric current, the first stage of the cables includes a multi-core copper wire insulated with a suitable material, the overall equivalent gauge of which is suitable for the power, voltage and current supplied to the subunit for converting into standardized power. In some embodiments, in which the power sources deliver a signal of 400 Hz, 115 V AC, the first stage of the cables includes a multi-core and twisted copper wire insulated with a suitable material, the overall equivalent gauge of which is suitable for the power, voltage and current supplied to the subunit for converting into standardized power.

In some embodiments, the second stage of cables is selected so as to provide efficient transmission of power from the standardized power conversion subunit to the AC generation subunit. In some embodiments, in which the standardized power conversion subunit produces power in the form of a 250 V DC signal, the second stage of cables includes a multi-strand copper wire insulated with a suitable material, the overall equivalent gauge of which is suitable for the power, voltage and current supplied to the standardized power conversion subunit.

In some embodiments, the third stage of the cables is selected and adapted so as to ensure efficient transmission of the high-frequency AC power signal from the output of the signal conversion unit to the control circuit. For example, the cable can be designed to reduce ohmic and electromagnetic losses caused by the high frequency of the signal, and can be shielded from external interference that can disrupt the integrity of the signal, as well as prevent signal leakage from the cable that can affect surrounding equipment and materials. In some embodiments, the third stage of the cables is a high-power and high-frequency transmission line in the form of a special coaxial cable. In some embodiments, the coaxial cable includes a conductor with a core, through which the input signal of the control circuit passes and which is made of a multi-strand copper wire of a sufficiently large outer diameter, which allows for the transmission of power with lower ohmic losses, a dielectric material surrounding the core, selected to improve electrical insulation and to withstand high voltage and temperature ranges, a shield conductor providing a return path for the signal to the alternating current generating subunit, made of a multi-strand and braided copper wire, of a sufficiently large equivalent gauge, which allows for the transmission of power with lower ohmic losses, a first casing, an insulating conductive shield, selected to withstand high voltage and temperature ranges, an outer shield, similar to the conductive shield, but not directly conducting current and used to shield the cable from external interference and to prevent leakage, and, finally, a second casing, similar to the first casing and insulating the outer shield.

In some embodiments, the fourth stage of the cables is selected and adapted to provide efficient transmission of the high-frequency and high-current AC power signal from the regulation circuit to the target areas. In some embodiments, this cable is configured to adjust the impedance between the regulation circuit and the target areas to reduce ohmic and electromagnetic losses caused by the high frequency of the signal, and can be shielded from external interference that can disrupt the integrity of the signal, as well as prevent signal leakage from the cable, which can affect the surrounding equipment and materials. In some embodiments, the fourth stage of the cables is a high-power, high-frequency and high-current transmission line in the form of a special coaxial cable similar to the embodiment described above in relation to the third stage of the cables, except for large cross-sections and diameters of the conductors and additional silver coating of the same conductors to improve the characteristics at high current and further reduce ohmic losses. In some embodiments, the fourth stage of the cables is further adapted using a litz wire-based design. The purpose of this design is to reduce proximity and skin effect losses in cables by making the conductors from materials thinner than the skin depth, individually insulated (e.g. using an enamel coating) and twisted or braided with perfect symmetry.

In general, the electrodes include a material through which the current will enter and leave the target region of the bulk medium. In some embodiments, a connector is used to connect the electrodes to the bulk medium. The connector refers to a fastening device that connects the electrodes to the bulk medium. In some embodiments, the electrodes and connectors are configured to reduce the contact resistance between the electrodes and the bulk medium. In other words, the electrodes are configured to average the potential difference that occurs in the target region for a given return path. If this contact resistance is higher than the resistance of the target region between the two electrodes, more heating will occur at the contact points than along the target region, all other things being equal, which reduces the efficiency of the heating system. In some embodiments, for similar reasons, the electrodes and connectors are configured to reduce the contact resistance between the electrodes and the wires (or cables) of the heating system. In some embodiments, the electrodes and connectors can also be configured to reduce electromagnetic losses (e.g., electromagnetic radiation).

In some embodiments, design features of electrodes for solving one or more of the above problems include: (1) selecting an electrode material having high conductivity, and (2) increasing the "real" contact area between the electrodes and the bulk medium, as well as between the electrodes and the wires. The "real" contact area refers to the barely noticeable contact between metals or between materials, due to which current flows from one material to another, often referred to as "conductive contact points". In some embodiments, connectors are also configured to solve these problems.

In some embodiments, the electrode material may include silver, copper, aluminum, carbon fiber composite, titanium, or an alloy thereof.

In some embodiments, the electrodes are part of cables used to transmit current into a volumetric medium.

In some embodiments, the geometry of the electrodes is configured to suit a specific target region and/or to reduce contact resistance between the electrodes and the bulk medium and/or to reduce electromagnetic losses.

In some embodiments, the electrodes may be round in shape.

In some embodiments, the electrodes are in the form of ends of cables used to supply current to the bulk medium.

In some embodiments, linear electrodes are used (e.g., rectangular electrodes whose length is greater than their width).

In some embodiments, electrodes in the form of two-dimensional spline curves of small thickness (in the third spatial dimension) are used.

In some embodiments, the cable conductor may be connected to the target area by clamping between the connector plate and the target area. For example, a portion of the side of the connector plate that contacts the target area may be milled. The cable conductor, by means of which the connection to the target area is realized, may be located in this milled portion. This configuration allows the electrode connector plate, under which the cable conductor is located, to be pressed or glued without the need to bend the connection to ensure proper fastening to the target area.

In general, there are various implementation options and design features of electrodes and connectors.

Fig. 17 is an illustration of an exemplary electrode 1700 with a round cross-section stud for the heating system 100. The electrode includes a round cross-section grounding stud connected to a disk 1710 made of a conductive material (e.g., aluminum), on which a threaded conductive material 1720 (e.g., aluminum) is mounted.

In some embodiments, a cable conductor connected to a target area via an electrode 1700 is uniformly wound around a threaded conductive material 1720, covering a significant portion of the surface area of both the threaded conductive material and the disk. In some embodiments, a nut and washer may be used to press the conductor against the disk 1710 on the threaded material 1720, which provides a larger contact area and lower contact resistance.

In some embodiments, the air gaps between the washer, cable, and disk 1710 are filled with electrically conductive and/or thermally conductive thermal paste, which provides improved thermal conductivity and/or electrical conductivity from the cable to the stud 1700.

In some embodiments, the electrode 1700 with a round cross-section stud is attached to the target area using a specially selected adhesive that has sufficient electrical conductivity and thermal conductivity to transfer heat and an electrical signal from the cable to the target area. In some embodiments, the adhesive also has sufficient strength to withstand the torque created by the nut and washer.

In some embodiments, the connector is a U-shaped device attached to the bulk medium and the electrodes in such a way that significant compressive resistance is created between the electrode and the bulk medium.

In some embodiments, the materials of the electrode and the connector may be selected to reduce their weight. In some embodiments, the electrode material is selected to improve electrical conductivity and/or thermal conductivity through the material in addition to reducing weight. Improved conductivity may be advantageous for electrode designs in which the current flowing from the cable to the target area passes through the electrode (e.g., a round stud, a single plate design).

In some embodiments, special housings may be included in the connector and electrode design. For example, such housings may be selected to pass environmental impact certification, including criteria such as thermal relief and/or thermal insulation, electrical insulation, electromagnetic interference shielding, corrosion protection, vibration and shock resistance, durability, protection from external contaminants and precipitation.

In general, various adhesion configurations (and combinations thereof) between the electrodes and/or connectors and the bulk medium are provided. In some embodiments, these configurations reduce the contact resistance between the electrodes and the bulk medium and/or reduce electromagnetic losses.

In some embodiments, the electrodes are connected to the bulk medium using a soldered joint. Fig. 18A shows a schematic illustration of an example fastening 1800 between an electrode 1802 and a target region 102 of the bulk medium, which is part of a larger bulk medium 1806, by means of a soldered joint. A soldering material is used to form the soldered joint 1804. For example, a low-temperature brazing alloy (e.g., AL 802) can be used to solder the electrodes to the target region in order to achieve low contact resistance. In some embodiments, the brazing alloy is coated with a flux to reduce oxidation (the formation of an aluminum oxide layer at the soldering point). The flux is a material that dissolves oxides at high temperatures and prevents re-oxidation of the surface before the brazing alloy is applied to the surface.

In some embodiments, the electrodes and the target area are connected to each other under the influence of pressure and temperature. For example, in some embodiments, a compressive force is applied between the electrodes and the target area. Without being limited by any theory, it is noted that the compressive force can reduce the contact resistance between the electrodes and the bulk medium in accordance with the following formula:

where ρ is the specific electrical resistance of the contact materials, H is the Vickers hardness of the softer of the contact surfaces, and F is the compressive or contact force.

In some embodiments, a compressive force may be applied to connect the electrodes and the bulk medium using a mechanical fastening connector. Fig. 18B is a schematic illustration of an example fastening configuration 1820 between the electrode 1802 and the target region 102, which is part of a larger bulk medium 1806. Solid rivets 1822 are used to apply a compressive force to connect the electrode to the target region.

In some embodiments, the compressive force may be applied using a vacuum tape or similar object capable of sealing the connection between the electrodes and the target area. Fig. 18C is a schematic illustration of an example configuration 1840 of fastening between the electrode 1802 and the target area 102, which is part of a larger volume environment 1806. An airtight tape 1842 is used to connect the electrode and the target area. After sealing is complete, a suction device can be used to create a vacuum between the electrodes and the target area, which brings them together and creates a compressive force.

In some embodiments, the compressive force may be applied using clamps that clamp the electrode and the target area and increase the pressure at the interface, such as using clamping clips.

In some embodiments, the compressive force can be applied using magnets or magnetized surfaces. In some embodiments, either the electrode surface or the target area surface is magnetized, which provides an attractive force between the magnets and the electrode and/or the contact area, resulting in the desired compressive force. In some embodiments, two or more magnets are used, and the electrode and the target area are located between them, which provides an attractive force between the magnets, resulting in the desired compressive force. In some embodiments, the electrode surface is magnetized, as well as the target area surface, which provides an attractive force between the electrode and the target area, resulting in the desired compressive force.

In some embodiments, the compressive force is applied by an external or internal clamping connector that adheres to or near the surface of the target area and converts the adhesive force into the desired compressive force. In some embodiments, adhesives (e.g., curable adhesives) can be used in combination with clamping connectors.

In some embodiments, the electrodes may be partially or completely embedded in the bulk medium using one of the above methods or an alternative technology.

In some embodiments, a conductive material (e.g., graphene) is located between the electrodes and the target area.

In some embodiments, the material of the connector used to connect the electrode to the target area is an adhesive selected for strength, which ensures long-term attachment to the target area. The strength of the adhesive may be advantageous in the case where the attachment area is relatively small and the mechanical constraints created in the attachment area are relatively high (for example, in the case of an electrode with a U-shaped stud). In one embodiment, when the electrode must remain in a stationary position for the adhesive to cure after its application, internal or external / disposable devices can be used to hold the electrode in place using adhesives and mechanical force.

In some embodiments, the material of the connector used to connect the electrode to the target area is also selected to provide higher thermal conductivity and/or electrical conductivity in order to provide better heat and current flow from the cable to the target area. For example, higher conductivity can be considered in the case where the electrode used is attached in such a way that the adhesive is in the path of the electrical current passing from the cable/electrode to the target area (for example, in the case of an electrode with a round cross-section pin and an electrode with a single plate). For this purpose, in some embodiments, nanomaterials (for example, carbon nanotubes) are located between the electrodes and the bulk medium. In some embodiments, the surface of the electrodes and the surface area of the bulk medium that will contact the electrodes (for example, the target area) can be processed to increase the "real" contact area between them.

In some embodiments and in combination with the above embodiments, as well as other embodiments, the connector, electrodes and a portion of the target area are coated with a material that reduces or eliminates electromagnetic losses.

In some embodiments, any combination of the above methods is used with any embodiment of the electrode and connector. For example, Fig. 18D is a schematic illustration of an example of a combination fastening 1860 between an electrode 1802 and a target region 102 of a volumetric medium 1806. This fastening includes a soldered joint 1804 and solid rivets 1822.

In some embodiments, the system may not require any connectors/cables since no physical contact is required to generate the required current. In this case, in some embodiments, the return signal path may be an additional section of wire leading back to the control circuit.

Embodiments of a heating system described herein may be used as an ice removal/anti-icing device to melt ice on an aircraft surface by applying high-frequency alternating current to a target area of the aircraft skin/airframe (e.g., to perform Joule heating). Heat generated in the target area of the airframe is transferred to the airframe surface and then transferred by convection across the airframe-ice interface to the ice. In some embodiments, the ice is completely melted. In some embodiments, a portion of the ice (the layer in direct contact with the airframe) is melted, resulting in the formation of a water layer between the ice and the airframe, as a result of which the ice may slide off or may be mechanically removed from the airframe. In some embodiments, heating is performed before ice appears, which prevents its formation.

In some embodiments, after the ice melts, high frequency alternating current is continued to maintain Joule heating of the airframe, which is transferred to the water formed/remaining on the surface due to conduction and convection.

Fig. 19-32 illustrates examples of nodes for transmitting and supplying electromagnetic energy in systems for heating a volumetric medium. The nodes (referred to herein as "connecting strips") are configured to function similarly to transmission lines in combination with a volumetric conductive medium to which they are attached. For example, in some embodiments, due to the design of the connecting strips, the volumetric medium itself conducts current similarly to the passage of current along a transmission line. The connecting strips can provide for the electromagnetic transmission of alternating current signals from the lines to the volumetric medium, thereby generating corresponding current signals in the volumetric medium. Thus, in essence, it can be said that due to the design of the connecting strip, the volumetric medium (in combination with the connecting strip) serves as a transmission line, or alternatively, the volumetric medium and the connecting strips together form a system that behaves like a transmission line and that can be analyzed and designed as such.

For example, as discussed above, embodiments of the present invention can be configured to heat a bulk medium by controlling the mechanisms for forming (e.g., narrowing, lengthening, etc.) a current in a conductive medium (e.g., a bulk medium, a conductor): for example, using the skin effect and the proximity effect. Both effects are based on the flow of a high-frequency alternating current through a conductive medium to be heated. The skin effect limits the current flow by using the tendency of an alternating electric current to distribute itself in a conductor in such a way that the current density is greatest near the surface of the conductor and decreases in the direction deeper into the conductor. The proximity effect can be used to further limit the current flow in a conductor by placing another alternating current path near an existing current path in the conductor. The proximity effect can also provide for the lengthening of the current path. Connecting strips can be used to create and control such effects in addition to the systems and processes discussed above. For example, connecting strips can be used with the various power management systems described above.

Fig. 19 is a sectional view of an example of a connecting strip 1900. The connecting strip 1900 can be used to apply high-frequency current signals to a volumetric medium, such as a skin 1902 of an aircraft, to heat the volumetric medium. The connecting strip 1900 has a multilayer structure that includes a first dielectric layer 1908 over the volumetric medium 1902, a conductive layer 1904 over the first dielectric layer 1908, a second dielectric layer 1908 over the conductive layer 1904, and a conductive shielding layer 1906 over the second dielectric layer 1908.

The first dielectric layer 1908 has a thickness of D ₁ . The conductive layer 1904 has a thickness of D ₂ . The second dielectric layer 1908 has a thickness of D ₃ . The conductive shielding layer 1906 has a thickness of D ₄ . The total thickness of the connecting strip 1900 is designated as D ₅ . The conductive layer 1904 can be made of conductive materials, including, without limitation, copper, copper alloys (for example, brass or bronze), silver, silver alloys, aluminum, aluminum alloys, titanium, titanium alloys, chromium, nickel, nickel alloys, cobalt alloys, stainless steel, graphite or combinations thereof. The conductive shielding layer 1906 can be made of conductive materials, including, but not limited to, copper, copper alloys (for example, brass or bronze), silver, silver alloys, aluminum, aluminum alloys, titanium titanium alloys, chromium, nickel, nickel alloys, cobalt alloys, stainless steel, graphite or combinations thereof. In some embodiments, the conductive shielding layer 1906 can be made in the form of a metal foil (for example, copper foil or aluminum foil) or in the form of a braided metal layer. The dielectric layers 1908 can be made of dielectric materials, including, but not limited to, Kapton, Mylar, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), rubber or a combination thereof.

In some embodiments, the connecting strip 1900 includes a protective layer over the conductive shielding layer. For example, the protective layer may include, without limitation, one or more layers of polyurethane, polyfluoride, paint, a film replacing paint, a sealant, or a combination thereof.

As illustrated in Fig. 20, the connecting strips 1900 can be arranged on the surface of a volumetric medium, such as a skin 2000 of an aircraft (for example, a wing), for supplying an electric current to the volumetric medium and heating the volumetric medium by generating and forming a current in the volumetric medium. The connecting strips 1900 extend along the surface of the skin of the aircraft 2000 and are located at a distance from each other. In some embodiments, one or more connecting strips 1900 include a short-circuited termination that electrically connects at least a portion of the connecting strip (e.g., the conductive layer 1904) to the bulk medium 1902. For example, the connecting strip 1900 can be terminated by an electrode, such as the electrodes discussed above, to form a closed circuit (e.g., a short-circuited circuit) between the conductive layer 1904 contained therein and the bulk medium 1902. The termination of the connecting strip 1900 is the distal end of the strip opposite the end to which current is supplied (e.g., opposite the end of the power input). In some embodiments, one or more connecting strips 1900 are terminated in an open circuit. An open termination means that the terminal end of the connecting strip 1900 is left as an open circuit; is not connected to an electrical ground through the bulk medium 1902 or the conductive shielding layer of the connecting strip 1900. In some embodiments, one or more connecting strips 1900 are terminated with an impedance adjustment component (e.g., a circuit element) connected between the connecting strip 1900 and the bulk medium 1902. For example, the connecting strip 1900 can be terminated with a capacitive, resistive, or inductive termination load. For example, a circuit element such as a capacitor, an inductor, or a resistor can be connected between the conductive layer 1904 of the connecting strip 1900 and the bulk medium 1902.

Referring to Fig. 19 and 20, a power management system (for example, the power management system 104 described above) is connected to one end of each of the connecting strips for supplying electric current to each strip. For example, a power supply line from the power management system can be connected to a conductive layer of each conductive strip 1900 and one or both volumetric media 1902 (for example, the skin 2000 of the aircraft) can be connected to an electrical ground.

The power management system supplies alternating current to each conductive strip 1900. For example, the power management system may supply alternating current with a frequency of 1 kHz to 450 MHz. In some embodiments, the frequency is from 1 MHz to 450 MHz. In some embodiments, the frequency is from 1 kHz to 1 MHz. The power management system may be configured to supply an alternating current of from 0.1 A to 200 A to each connecting strip 1900. For example, the power supply of the power management system and the electrical arrangement of the connecting strips 1900 may be configured to supply a desired amount of current (e.g., from 0.1 A to 200 A) to each connecting strip 1900. As a general example, if the connecting strips 1900 are connected to the power management system in series, a 100 A power supply may be used to supply a current of 100 A to each connecting strip 1900. If ten connecting strips 1900 are connected to the power management system in parallel, a 100 A power supply may be used to supply a current of 10 A to each connecting strip 1900. It should be noted that this example assumes that the impedances of the connecting strips are equal. As discussed below, the impedance of the 1900 connecting strips can be adjusted in various ways to control the distribution of current between the connecting strips, which may be desired or may be required in particular heating applications.

An alternating current for heating the aircraft skin 1902 is supplied through the conductive layer 1904. The alternating current supplied through the conductive layer 1904 generates (e.g., due to electromagnetic capacitive and inductive coupling) a corresponding current in the aircraft skin 1902, as shown in Figs. 22A-22B. Figs. 22A-22B show graphs obtained as a result of electromagnetic finite element analysis simulating the performance of an exemplary connecting strip 1900 attached to a conductive volumetric medium 1902. In the graph of Fig. 22A, the volumetric medium 1902 (e.g., modeled as the aircraft skin), the conductive layer 1904, and the conductive shielding layer 1906 are designated. In Fig. 22B, the individual components of the connecting strip 1900 are not shown, and only the connecting strip 1900 (shown generally) and the volumetric medium 1902 are indicated. The region indicated by the reference numeral 2206 in both graphs represents the background medium (e.g., the atmosphere). Both graphs show the reduced current density (in A/m ² ) induced in the volumetric medium 1902 and indicated by the shaded region 2204. The current density in the volumetric medium 1902 is maximum in a narrow region 2204 near the surface of the volumetric medium 1902. In addition, in the graph of FIG. 22A shows the reduced electric field strength (light gray area 2202) in the dielectric layers of the connecting strip 1900. It should be noted that the conductive shielding layer 1906 shields the environment 2206 from electric fields generated by the current passing through the conductive layer 1904, for example, to reduce or eliminate electromagnetic radiation and to protect the connecting strip 1900 from external electromagnetic interference. The bulk medium 1902 also serves as a shielding layer, for example, by minimizing or blocking electric fields. Thus, the conductive shielding layer 1906 and the bulk medium 1902 in embodiments of the connecting strip 1900 can serve to contain electric fields in the connecting strip 1900 (for example, between the conductive shielding layer 1906 and the bulk medium 1902). This effect reduces or eliminates electromagnetic interference between the heating system and other nearby electrical components. Embodiments of the connecting strip 1900 in combination with the bulk medium 1902 can provide performance characteristics comparable to stripline transmission lines.

Referring to Fig. 19, the heating effect of the conductive strips 1900 on the bulk medium, as well as the impedance of each conductive strip 1900, can be adjusted by changing the characteristics of the conductive strip, such as, for example, the thickness of the various layers 1904, 1906 and 1908; the width of the conductive layer; the arrangement of the conductive layer; the materials of each layer, including their dielectric constants and conductivity properties; or by adding impedance adjustment components (for example, capacitors, inductors and resistors). In addition, the heating effect of the current generated in the bulk medium 1902 can also be changed by changing these characteristics, which also serve to adjust the proximity effect and the path of the heating current passing through the bulk medium 1902, as discussed above.

For example, each of the layers 1904, 1906, 1908 can have a corresponding thickness (D1-D4), typically in the range of 0.1 mil to 1 inch or in some embodiments from 0.5 mil to 10 mil. In some embodiments, the connecting strip 1900 can have different distances separating the conductive layer 1904 from the bulk medium 1902 and separating the conductive layer 1904 from the conductive shielding layer 1906. In some embodiments, these distances are related by a ratio. For example, the connecting strip 1900 can be formed such that the relative thickness D ₁ and the relative thickness D ₃ of the dielectric layer 1908 are related by a ratio. For example, in some embodiments, the ratio D ₁ : D ₃ can be in the range of 1:1 to 1:5. In other embodiments, the ratio D ₁ :D ₃ may be in the range of 1:1 to 5:1, for example, to obtain a desired current density and/or impedance value for a given application. In one exemplary embodiment, D ₁ is 3 mils, D ₂ is 1 mil, D ₃ is 3 mils, and D ₄ is 1 mil. In another exemplary embodiment, D ₁ is 7.2 mils, D ₂ is 1.4 mils, D ₃ is 2.4 mils, and D ₄ is 1.4 mils. In yet another embodiment, D ₁ is 1000 mils, D ₂ is 50 mils, D ₃ is 500 mils, and D ₄ is 50 mils. In yet another embodiment, D ₁ is 10 mils, D ₂ is 2.5 mils, D ₃ is 50 mils, and D ₄ is 2.5 mils. In yet another example, D ₁ is 2.4 mils, D ₂ is 1.4 mils, D ₃ is 7.2 mils, and D ₄ is 1.4 mils. In yet another example, D _i is 17.6 mils, D ₂ is 9.8 mils, D ₃ is 24.5 mils, and D ₄ is 9.8 mils. In yet another example, D ₁ is 100 mils, D ₂ is 20 mils, D ₃ is 250 mils, and D ₄ is 20 mils. In yet another example, D ₁ is 5.5 mils, D ₂ is 2.5 mils, D ₃ is 9.0 mils, and D ₄ is 2.5 mils. In yet another example, D ₁ is 1.5 inches, D 2 is 0.25 inches, D ₃ is 2.2 inches, and D ₄ is 0.25 inches. In another example, D ₁ is 3.8 mils, D ₂ is 2 mils, D ₃ is 3.8 mils, and D ₄ is 2 mils. In another example, D ₁ is 2.9 mils, D ₂ is 1.5 mils, D ₃ is 5.8 mils, and D ₄ is 2.5 mils. In an additional example, D ₁ is 5 mils, D ₂ is 2.5 mils, D ₃ is 25 mils, and D ₄ is 1.5 inches. In another example, D ₁ is 11 mils, D ₂ is 3 mils, D ₃ is 5.5 mils, and D ₄ is 3 mils. In yet another example, D ₁ is 21 mils, D ₂ is 1.5 mils, D ₃ is 7 mils, and D ₄ is 2.5 mils. In a further example, D ₁ is 10 mils, D ₂ is 2.5 mils, D ₃ is 2 mils, and D ₄ is 2.5 inches. In yet another further example, D ₁ is 4.5 inches, D ₂ is 0.25 inches, D ₃ is 1.5 inches, and D ₄ is 0.25 inches. In another exemplary embodiment, D ₁ is 3 mils, D ₂ is 1 mil, D ₃ is 3 mils, and D ₄ is 1 mil. In yet another example, D ₁ is 10.2 mils, D ₂ is 3.5 mils, D ₃ is 40.8 mils, and D ₄ is 2.5 mils. In yet another example, D ₁ is 4.8 mils, D ₂ is 0.5 mils, D ₃ is 14.4 mils, and D ₄ is 0.5 mils. In another example, D ₁ is 15 mils, D ₂ is 1.4 mils, D ₃ is 3 mils, and D ₄ is 1.4 mils. In another example, D ₁ is 113 mils, D ₂ is 10 mils, D ₃ is 28.25 mils, and D ₄ is 10 mils. In another example, D ₁ is 127 mils, D ₂ is 5 mils, D ₃ is 254 mils, and D ₄ is 10 mils. In another example, D ₁ is 53 mils, D ₂ is 12 mils, D ₃ is 159 mils, and D ₄ is 12 mils. In another example, D ₁ is 13 mils, D ₂ is 1.4 mils, D ₃ is 2.6 mils, and D ₄ is 1.4 mils. In another example, D ₁ is 23 mils, D ₂ is 4 mils, D ₃ is 46 mils, and D ₄ is 4 mils. In another example, D ₁ is 11.5 mils, D ₂ is 2.8 mils, D ₃ is 57.5 mils, and D ₄ is 2.8 mils. In another example, D ₁ is 10 mils, D ₂ is 1.4 mils, D ₃ is 2.5 mils, and D ₄ is 1.4 mils.

In addition, the width of the conductive layer 1904 may typically be in the range of several inches or several mils across the layer. Fig. 21 shows a top view of several example connection strips (examples 1-9) to demonstrate various configurations of the conductive layer 1904 in the connection strip 1900. It should be noted that for purposes of clarity, the connection strips 1900 in Fig. 21 are shown without layers located above the conductive layer 1904 (e.g., without a second dielectric layer and a conductive shield layer). The cross-sectional area of the conductive layer 1904 can vary along its length. For example, the width of the conductive layer 1904 can vary along its length to adjust the impedance of the connection strip 1900 and, in some cases, to adjust the current density in the bulk medium and the conductive layer. Examples 1-9 illustrate several exemplary variations in the width of the conductive layer 1904 of the connecting strip 1900. For example, the width of the conductive layer 1904 across the connecting strip 1900 can vary from a maximum width to a minimum width. In some embodiments, the maximum width is only 1.5 times the minimum width. In other embodiments, the maximum width is 100 times the minimum width. For example, the width of the conductive layer 1904 shown in Example 1 can be 1.5 inches at the widest point (e.g., at the upper end) and 1 inch at the narrowest point (e.g., at the lower end). In another example, the width of the conductive layer 1904 shown in Example 1 can be 1 inch at the widest point (e.g., at the upper end) and 10 mils at the narrowest point (e.g., at the lower end).

In some embodiments, the thickness of the conductive layer 1904 may vary along its length. For example, the width of the conductive layer 1904 may vary along its length to adjust the impedance of the connecting strip 1900. In some embodiments, the thickness, width, and material of the conductive layer 1904 may vary along its length.

In some embodiments, the impedance of the coupling strip 1900 can be adjusted by adding impedance adjustment components (e.g., capacitors, inductors, and resistors) at one or more locations along the length of the conductive layer 1904. For example, the conductive layer can be divided into several segments along the length, wherein one or more impedance adjustment components connect the segments. For example, with reference to the coupling strip of Example 4 in Fig. 21, the conductive layer 1904 can be divided into two segments in the region 2102 and the impedance adjustment component (e.g., a capacitor, inductor, resistor, or a combination thereof) can be electrically connected between each adjacent segment. Alternatively or in addition, the impedance adjustment component can be connected to the conductive layer as a shunt element between the conductive layer 1904 and either the bulk medium 1902 or the conductive shielding layer 1906.

In some embodiments, the width, thickness, or both of the conductive shielding layer 1906 may vary along the length of the connecting strip 1900. In some embodiments, the width, thickness, or both of the dielectric layers 1908 may vary along the length of the connecting strip 1900. For example, in some embodiments, the cross-sectional areas of the conductive layer 1904, the dielectric layers 1908, and the conductive shielding layer 1906 may vary along the length of the strip 1900.

Fig. 23 shows schematic illustrations of arrangement patterns (arrangement patterns A-E) of several exemplary arrangements of conductive layer 1904 in a connecting strip 1900. Initially, in a linear arrangement (as shown in Fig. 21), conductive layer 1904 extends linearly along the length of connecting strip 1900. Arrangements patterns A-E illustrate connecting strips 1900 in which conductive layer 1904 is arranged in such a way as to correspond to a nonlinear model or nonlinear path. In particular, in the examples of Fig. 23, conductive layer 1904 is shown arranged in various serpentine patterns. The illustrated serpentine patterns provide for the arrangement of segments of the conductive layer 1904 next to each other in the width direction of the connecting strip 1900. Such an arrangement allows for a reduction in the overall length of the connecting strip 1900 while maintaining the required overall length of the conductive layer 1904. In some application areas, maintaining a relatively constant length of the conductive layer 1904 in different connecting strips 1900 helps to maintain the same impedance between connecting strips 1900 of different lengths. For example, in each of the Schemes A and B of the arrangement, the conductive layer 1904 can have the same overall length. However, the overall length of the connecting strip 1900 in the Scheme B of the arrangement can be reduced to half the length of the connecting strip 1900 with a conductive layer with a linear arrangement (for example, as shown in Fig. 21). In a similar manner, the overall length of the connecting strip 1900 in the arrangement Scheme C can be reduced to one third of the length of the connecting strip 1900 with a conductive layer with a linear arrangement. In addition, connecting strips 1900 of shorter length can be placed in areas of the aircraft body with limited space. For example, connecting strips 1900 with a conductive layer arranged according to the arrangement Schemes A-E can be placed in narrow areas of the wing (for example, on the wing tips), in which too long a connecting strip 1900 with a linear arrangement of the conductive layer cannot be installed.

Each of the Arrangement Diagrams A-E illustrates a connecting strip 1900 having a conductive layer 1904 arranged along a non-linear path from an input end 2302 to an output end 2304. Arrangement Diagram A illustrates a connecting strip 1900 with a conductive layer 1904 arranged with a double overlap. The conductive layer 1904 in Arrangement Diagram A includes two segments arranged next to each other, for example, along a U-shaped path from the input end 2302 to the output end 2304. Fig. 24A shows a sectional view taken along line A-A' of the connecting strip 1900 according to Arrangement Diagram A.

The arrangement diagram B illustrates a connecting strip 1900 with a conductive layer 1904 arranged with a three-fold overlap. The conductive layer 1904 in the arrangement diagram B includes three segments arranged next to each other, for example, along an S-shaped path from the input end 2302 to the terminal end 2304. Fig. 24B shows a sectional view taken along the line B-B' of the connecting strip 1900 according to the arrangement diagram B.

The arrangement schemes C and D illustrate the connecting strips 1900 with the conductive layer 1904 with different variations of the arrangement with a four-fold overlap. The conductive layer 1904 in each of the arrangement schemes C and D includes four segments arranged next to each other. In the arrangement scheme C, the segments of the conductive layer 1904 are arranged, for example, along an M-shaped path (or a W-shaped path) from the input end 2302 to the terminal end 2304. In the arrangement scheme D, the segments of the conductive layer 1904 are arranged, for example, in the form of an arrangement with a two-fold overlap, folded along itself. A similar technology can also be applied to a three-fold configuration by folding the conductive layer 1904 along itself. Fig. 24C shows a sectional view taken along the line C-C' of the connecting strip 1900 according to the arrangement scheme C and the arrangement scheme D.

The arrangement diagram E illustrates a more general arrangement of the conductive layer 1904. For example, the arrangement diagram E illustrates an example of the conductive layer 1904 with a plurality of segments of different widths arranged next to each other. In addition, in some embodiments, the conductive layer 1904 may include internal connections 2306 between segments at various locations between segments, as shown in the arrangement diagram E. In some embodiments, the connecting strip 1900 may also include a plurality of signal inputs 2302.

Fig. 25A shows a sectional view of an example configuration for fastening the connecting strip 1900 to the volumetric medium 1902. In particular, Fig. 25A shows a bottom fastening configuration. In the bottom fastening configuration, the adhesive material 2502 is located between the bottom surface of the connecting strip 1900 (e.g., the bottom dielectric layer) and the surface of the volumetric medium 1902. For example, the adhesive material can be, without limitation, a layer of double-sided adhesive (e.g., double-sided tape), resin, or epoxy resin.

Fig. 25B shows a sectional view of another exemplary configuration for fastening the connecting strip 1900 to the volumetric medium 1902. In particular, Fig. 25B shows a top-fastening configuration. In the top-fastening configuration, an adhesive layer 2504 is applied over the connecting strip 1900 for fastening the connecting strip 1900 to the aircraft skin 1902. The adhesive layer 2504 may be, for example, an adhesive coating, an adhesive film, or a tape.

Fig. 26A is a cross-sectional view of the connecting strip 1900 with a double-sided adhesive bottom layer before being mounted on the bulk medium 1902, and Fig. 26B is a cross-sectional view of the connecting strip 1900 of Fig. 26A mounted on the bulk medium 1902. In some embodiments, such as in a bottom-mounted configuration, the connecting strip 1900 includes an adhesive bottom layer 2608. The adhesive bottom layer can be made of a double-sided adhesive material (e.g., double-sided adhesive tape). In such embodiments, the double-sided adhesive material can serve as a lower dielectric layer (e.g., lower dielectric layer 1908 in Fig. 19). In some embodiments, the adhesive bottom layer 2608 may be, for example, an adhesive coating or an adhesive film applied to the lower surface of the lower dielectric layer 1908. Before installation, the connecting strip 1900 with the adhesive bottom layer 2608 may include a protective layer 2610 over the adhesive bottom layer 2608. The protective layer 2610 may be, for example, a peel-off layer. For example, the protective layer 2610 may protect the adhesive bottom layer 2608 before installation. During installation, the protective layer 2610 can be removed from the adhesive bottom layer 2608, exposing the adhesive surface, so that the connecting strip 1900 can be attached to the surface of the bulk medium 1902.

In some embodiments, one or more adhesive layers 2604 and 2606 may be included for attaching the dielectric layer 1908 to the conductive layer 1904 and/or for attaching the conductive shielding layer 1906 to the dielectric layer 1908. In some embodiments, the connecting strip 1900 includes a protective layer 2602 over the conductive shielding layer 1906. For example, the protective layer 2602 may include, without limitation, one or more layers of polyurethane, polyfluoride, paint, paint replacement film, sealant, or a combination thereof.

In some applications, it may be necessary to heat a non-conductive bulk medium. In such situations, the heating systems and connecting strips described herein may be modified to heat a non-conductive bulk medium. For example, an embedded layer may be used to heat a non-conductive bulk medium using a heating system using connecting strips.

Fig. 27A-27F are sectional views of various embodiments of the integrated connection strips. Fig. 27A shows a connection strip 2700 similar to the connection strip 1900 in Fig. 19. Like the connection strip 1900, the connection strip 2700 has a multilayer structure that includes a first dielectric layer 1908 over a bulk medium 1902, a conductive layer 1904 over the first dielectric layer 1908, a second dielectric layer 1908 over the conductive layer 1904, and a conductive shielding layer 1906 over the second dielectric layer 1908, and, optionally, a protective layer 2706 over the conductive shielding layer 1906. The protective layer 2706 is similar to the protective layer 2602 described above. The connecting strip 2700 differs from the connecting strip 1900 in that it is attached to the surface of the non-conductive volumetric medium 2702, and the non-conductive volumetric medium 2702 includes a bulk conductive material 2704 embedded therein. For example, the bulk conductive material 2704 can be in the form of a metal foil, a metal tape, or a braided metal layer embedded in the non-conductive bulk medium 2702. For example, the non-conductive bulk medium 2702 can be a layered material (e.g., a carbon fiber composite, a glass composite, or Kevlar) with the conductive bulk material 2704 located between layers of the non-conductive bulk medium 2702. The bulk conductive material 2704 can be made of conductive materials including, without limitation, copper, copper alloys (e.g., brass or bronze), silver, silver alloys, aluminum, aluminum alloys, titanium, titanium alloys, chromium, nickel, nickel alloys, cobalt alloys, stainless steel, graphite, or combinations thereof.

In each of the examples shown in Fig. 27A-27F, the alternating current passing through the conductive layer 1904 of the connecting strip 2700 generates a heating current in the bulk conductive material 2704, and not in the non-conductive bulk medium 2702. Then, the heat generated in the bulk conductive material 2704 is transferred to the non-conductive bulk medium 2702 (e.g., by conduction). In some examples, if the non-conductive bulk medium has some electrical conductivity, heat will also be generated in the non-conductive region in addition to the layer of bulk conductive material.

Fig. 27B illustrates an embodiment of a connecting strip 2700 that includes only a protective layer 2706, a conductive layer 1904, and a dielectric layer 1908. The connecting strip 2700 is arranged such that the protective layer 2706 is located on top of the conductive layer 1904, and the conductive layer 1904 is located on top of the dielectric layer 1908. The dielectric layer 1908 is separated from the embedded conductive bulk material 2704 by a portion of a non-conductive bulk medium 2702.

Fig. 27C illustrates an embodiment of a connecting strip 2700 that includes a conductive layer 1904 embedded in a non-conductive bulk medium 2702. The connecting strip 2700 in Fig. 27C includes a protective layer 2706, a conductive shielding layer 1906, a dielectric layer 1908 and a conductive layer 1904. The connecting strip 2700 is arranged so that the protective layer 2706, the conductive shielding layer 1906 and the dielectric layer 1908 are located on top of the conductive layer 1904. The conductive layer 1904 is embedded in the non-conductive volumetric medium 2702 and is separated from the conductive volumetric material 2704 by a portion of the non-conductive volumetric medium 2702. For example, each of the conductive layer 1904 and the conductive volumetric material 2704 can be located between different layers of the non-conductive volumetric medium 2702.

Fig. 27D illustrates a variant of the connecting strip 2700 shown in Fig. 27C, but without the protective layer 2706, the conductive shielding layer 1906 and the dielectric layer 1908.

Fig. 27E illustrates a variant of the connecting strip 2700 shown in Fig. 27D, but with the reverse arrangement of the conductive layer 1904 and the conductive bulk material 2704. That is, in the arrangement of the connecting strip 2700 shown in Fig. 27E, the conductive bulk material 2704 is located closer to the surface of the non-conductive bulk medium 2702 than the conductive layer 1904.

Fig. 27F illustrates an embodiment of a connecting strip 2700 that includes a conductive layer 1904 and a conductive shielding layer 1906 embedded in a non-conductive bulk medium 2702. In the arrangement of the connecting strip 2700 shown in Fig. 27F, portions of the non-conductive bulk medium 2702 (e.g., layers of the non-conductive bulk medium 2702) separate the conductive layer 1904 from the conductive shielding layer 1906 and from the conductive bulk material 2704. The non-conductive bulk medium 2702 performs the same function as the dielectric layers 1908 in the connecting strip 1900 shown in Fig. 19.

Fig. 28 shows schematic illustrations of one embodiment of a connector 2802 of a connecting strip. Schematic illustration 2805 is a basic diagram of a connector 2802. The connector 2802 includes a built-in impedance adjustment circuit 2804. The impedance adjustment circuit 2804 is electrically connected between the input signal interface 2806 and the connecting strip 1900. For example, the input signal interface 2806 can be a coaxial cable connection. The input terminal 2810 of the input signal interface 2806 (for example, the central wire of the coaxial cable connection) is connected to the conductive layer 1904 of the connecting strip 1900 by a wire 2808. The ground terminal(s) 2814 of the input signal interface 2806 (for example, the shield of the coaxial cable connection) is connected to the volumetric medium 1902 and/or to the conductive shielding layer 1906 of the connecting strip 1900 by one or more wires 2812.

The impedance adjustment circuit 2804 is configured to adjust the input impedance of the coupling strip 1900 to a desired level, which is measured at the input signal interface 2806. The impedance adjustment circuit 2804 may be a fixed or variable impedance adjustment circuit. For example, the impedance adjustment circuit 2804 may be implemented as one of the impedance adjustment circuits described above with reference to Fig. 12-15B. In the schematic illustration 2850, the impedance adjustment circuit 2804 is implemented as a shunt capacitor C ₁ between the ground connected to the conductive shielding layer 1906 of the coupling strip 1900 and/or to the bulk medium 1902 (or the bulk conductive material 2704 in the case of implementation for a non-conductive bulk medium).

Fig. 29 shows schematic illustrations of another embodiment of a connector 2902 of a connecting strip. The connector 2902 includes two input signal interfaces 2906A and 2906B, for example, for connecting a plurality of connecting strips 1900 to each other in series. Schematic illustration 2905 is a basic diagram of the connector 2902. The connector 2902 includes a built-in impedance adjustment circuit 2904. The impedance adjustment circuit 2904 includes series shunt components 2904A, 2904B, 2904C of impedance adjustment, electrically connected between the input signal interfaces 2906A, 2906B and the connecting strip 1900. For example, the input signal interfaces 2906A and 2906B can be connections of coaxial cables. The corresponding input terminals 22910 of the input signal interfaces 2906A, 2906B are connected to the conductive layer 1904 of the connecting strip 1900 and to each other by a wire 2808. The corresponding ground terminal(s) 2914 of the input signal interfaces 2906A, 2906B are connected to the bulk medium 1902 and/or to the conductive shielding layer 1906 of the connecting strip 1900 by one or more wires 2912.

In the schematic representation 2950, the impedance adjustment circuit 2804 is implemented in the form of a series capacitor C ₁ and two shunt capacitors C ₂ , C ₃ between the ground connected to the conductive shielding layer 1906 of the connecting strip 1900 and/or to the bulk medium 1902 (or the bulk conductive material 2704 in the case of implementation for a non-conductive bulk medium).

Fig. 30 is a block diagram of a first example system 3000 for heating a volumetric medium using connecting strips 1900 according to embodiments of the present invention. The heating system 3000 includes a plurality of connecting strips 1900 located at a distance from each other and attached to a volumetric medium 1902 (for example, to an aircraft wing). Each connecting strip 1900 is connected to a power management system 3002. The power management system 3002 can be implemented according to any of the embodiments of the power management system 104 discussed above. The power management system 3002 supplies alternating current to each strip.

One end of each connecting strip 1900 (referred to herein as the "input end") is connected to the power management system 3002 via a connector 3004. In the illustrated example, the opposite end of each connecting strip 1900 (referred to herein as the "termination end") has either an open termination 3006 or a closed termination 3008. The connecting strips 1900 are arranged in an alternating manner, with each adjacent pair of connecting strips 1900 having terminations of a different type. For example, one connecting strip 1900 in each adjacent pair is provided with an open termination 3006 at the termination end, while the other connecting strip 1900 in the pair is provided with a closed termination 3008. Open terminations 3006 mean that the termination end of the connecting strip 1900 is left as an open circuit; is not connected to electrical ground through the bulk medium 1902 or the conductive shielding layer of the connecting strip 1900. In some embodiments, the closed termination loads 3008 are short-circuited circuits between the conductive layer of the connecting strip 1900 and the bulk medium 1902 and/or the conductive shielding layer of the connecting strip 1900. In some embodiments, the closed termination loads 3008 are capacitive termination loads, wherein a capacitor is connected between the conductive layer of the connecting strip 1900 and electrical ground. For example, the capacitor is connected between the conductive layer of the connecting strip 1900 and either the bulk medium 1902 or the conductive shielding layer of the connecting strip 1900. In some embodiments, the closed termination loads 3008 are inductive termination loads, and an inductor is connected between the conductive layer of the connecting strip 1900 and the electrical ground. For example, the inductor is connected between the conductive layer of the connecting strip 1900 and either the bulk medium 1902 or the conductive shielding layer of the connecting strip 1900. In some embodiments, the closed termination loads 3008 are resistive termination loads, and a resistor is connected between the conductive layer of the connecting strip 1900 and the electrical ground. For example, a resistor is connected between a conductive layer of the connecting strip 1900 and either the bulk medium 1902 or the conductive shielding layer of the connecting strip 1900.

Complementary types of termination loads can be applied to adjacent connection strips 1900 to provide the necessary input impedance in the power management system 3002, to provide the necessary heat distribution in the volumetric environment 1902, or to perform both functions. For example, the connection strips 1900 can be installed on the volumetric environment 1902 such that adjacent connection strips 1900 have complementary types of termination loads. For example, the termination loads of adjacent connection strips 1900 can alternate between open termination loads 3006 and short-circuited termination loads (for example, a closed termination load 3008 implemented in the form of short-circuited circuits). In yet another example, the terminations of adjacent connecting strips 1900 may alternate between a closed termination 3008 implemented as capacitive terminations and a closed termination 3008 implemented as inductive terminations.

Fig. 31 is a block diagram of a second example system 3100 for heating a bulk medium using connecting strips 1900 according to embodiments of the present invention. The heating system 3100 is similar to the heating system 3000 described above, with the addition of a control system 3102 configured to control variable termination loads 3106 attached to the end of each connecting strip 1900. The variable termination loads 3106 include a switchable termination load. In some embodiments, the variable termination loads 3106 are configured to switch between a short-circuited termination load and an open termination load. For example, the variable termination loads 3106 include a controllable switch connected between a conductive layer of the connecting strip 1900 and electrical ground. The controlled switch may be implemented as an electronic switch (e.g., a transistor, a power diode, a thyristor, a silicon controlled rectifier, etc.) or a mechanical switch (e.g., a relay). For example, the controlled switch is connected between the conductive layer of the connecting strip 1900 and either the bulk medium 1902 or the conductive shielding layer of the connecting strip 1900. The output of the control system is connected to the control terminal of the controlled switch.

The termination load of each connecting strip 1900 can be switched between an open circuit and a short circuit by opening and closing a controlled switch (or turning on and off an electronic switch). For example, the control system 3102 controls the operation of the variable termination loads 3106 of the connecting strip 1900 by controlling the controlled switch to change the type of termination load of the connecting strip 1900 as needed to heat the bulk medium 1902. In some embodiments, the control system 3102 is configured to independently control each variable termination load 3106 of the connecting strip. In some embodiments, the control system 3102 is configured to synchronously control the variable termination loads 3106 of a group (for example, a pair or a larger group) of connecting strips. In some embodiments, the control system 3102 is configured to control the variable termination loads 3106 of one or more connecting strips 1900 at regular time intervals, for example, according to a regular duty cycle. The duty cycle for switching the variable termination loads 3106 can be in the range from 0.01 Hz to 100 Hz.

In some embodiments, the control system 3102 controls the operation of the variable termination loads 3106 by alternately switching between open and closed termination loads. For example, the control system 3102 switches half of the variable termination loads 3106 to short-circuited termination loads and half of the variable termination loads 3106 to open termination loads in the first half of the duty cycle. Then, in the second half of the duty cycle, the control system 3102 switches the variable termination loads 3106 such that the termination loads switched to open termination loads are switched to closed termination loads, and vice versa. The duty cycle for switching the variable termination loads 3106 can be in the range from 0.01 Hz to 100 Hz.

In some embodiments, the variable termination loads 3106 of each pair of adjacent connector strips 1900 are controlled to maintain opposite termination load types. That is, the control system 3102 controls the variable termination loads 3106 such that the termination load of one connector strip 1900 in each adjacent pair is configured as an open circuit, and the termination load of the other connector strip 1900 in the pair is configured as an open circuit, with the termination loads alternating in each half of the duty cycle.

The control system 3102 may be a computing device with one or more processors or microcontrollers configured to control the operation of the variable termination loads 3106. For example, the control system 3102 includes a memory device that stores instructions (e.g., program code) that, when executed by the control system, cause the control system 3102 to supply corresponding control signals to the controlled switches in the variable termination loads 3106. In some embodiments, the power management system 3002 and the control system 3102 may be combined into a common power management and control system.

In some embodiments, the variable termination loads 3106 are configured to switch between a capacitive termination load and an inductive termination load. For example, the controllable switch can be configured to switch between connecting the conductive layer of the connection strip 1900 to a capacitor that is connected to ground, or connecting the conductive layer of the connection strip 1900 to an inductor that is connected to ground. As noted above, the ground can pass either through the bulk medium 1902 or through the conductive shielding layer of the connection strip 1900. In addition, in such embodiments, the control system 3102 can operate, as described above, to alternately switch the variable termination loads 3106 between conductive and inductive termination loads.

In other embodiments, the variable termination loads 3106 may be modified to switch between different types of termination loads, such as between open termination loads and capacitive termination loads, between short termination loads and inductive termination loads, between open termination loads and inductive termination loads, between short termination loads and capacitive termination loads, between open termination loads and resistive termination loads, between short termination loads and resistive termination loads, or other combinations thereof.

Fig. 32 is a block diagram of a third example system 3200 for heating a bulk medium using connecting strips according to embodiments of the present invention. The heating system 3200 is configured to alternately actuate adjacent connecting strips 1900. The heating system 3200 is similar to the heating system 3000 described above, with the addition of a control system 3202 configured to actuate switchable connectors 3204 attached to the input end of each connecting strip 1900. The switchable connectors 3204 include a controllable switch configured to connect and disconnect a corresponding connecting strip 1900 to the power control system 3002. The controllable switch can be implemented as an electronic switch (e.g., a transistor, a power diode, a thyristor, a silicon controlled rectifier, etc.) or a mechanical switch (e.g., a relay). For example, a controlled switch is connected between the conductive layer of the connecting strip 1900 and the input terminal of the switching connector 3204. The output of the control system is connected to the control terminal of the controlled switch.

The control system 3202 controls the operation of the switchable connector 3204 to alternately connect and disconnect the connecting strips 1900 from the power management system 3002, effectively connecting and disconnecting the connecting strips 1900. For example, the control system 3202 can control the switchable connectors 3204 to alternately connect and disconnect the connecting strips 1900. For example, the control system 3202 controls the operation of the switchable connectors 3204 of the connecting strip 1900 by controlling the controllable switch to connect or disconnect the connecting strip 1900 as needed to heat the bulk medium 1902. In some embodiments, the control system 3102 is configured to independently control each variable termination load 3106 of the connecting strip. In some embodiments, the control system 3102 is configured to synchronously control the variable termination loads 3106 of a group (for example, a pair or a larger group) of connecting strips. In some embodiments, the control system 3102 is configured to control the switching of the variable termination loads 3106 of one or more coupling strips 1900 at regular intervals, such as according to a regular duty cycle. The duty cycle for switching the variable termination loads 3106 can be in the range from 0.01 Hz to 100 Hz. In some embodiments, the control system 3202 connects the coupling strips 1900 with open termination loads 3006 and disconnects the coupling strips 1900 with closed termination loads 3008 in the first half of the duty cycle. Then, in the second half of the duty cycle, the control system 3202 switches the switchable connectors 3204 to disconnect the coupling strips 1900 with open termination loads 3006 and connect the coupling strips 1900 with closed termination loads 3008.

The control system 3202 may be a computing device with one or more processors or microcontrollers configured to control the operation of the variable termination loads 3106. For example, the control system 3202 includes a memory device that stores instructions (e.g., program code) that, when executed by the control system, cause the control system 3202 to supply corresponding control signals to the controlled switches in the variable termination loads 3106. In some embodiments, the power management system 3002 and the control system 3202 may be combined into a common power management and control system.

As used herein, the terms "perpendicular" or "substantially perpendicular" or "at right angles" or "at substantially right angles" refer to the relative position of two elements (e.g., lines, directions, axes, planes, surfaces, or components) that forms an angle of ninety degrees within the tolerances of design or measurement. For example, directions may be considered perpendicular if the angle between the directions is within the tolerances of ninety degrees (e.g., ±1-2 degrees).

Although the present application contains many specific details of embodiments, these should not be construed as limiting the scope of any invention or the scope of what may be claimed, but as descriptions of features that may be specific to particular embodiments of particular inventions. Certain features described herein in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in a plurality of embodiments, individually or in any suitable subcombination. Furthermore, although features may be described above as operating in certain combinations, and even initially claimed as such, one or more features from a claimed combination may in some cases be omitted from the combination, and the claimed combination may refer to a subcombination or variation of a subcombination.

Similarly, although operations are depicted in the drawings in a particular order, this should not be understood as a requirement that such operations must be performed in the particular order shown or in a sequential order, or that all illustrated operations must be performed to achieve the desired result. In certain circumstances, multitasking and parallel processing may be advantageous. Furthermore, the separation of various modules and components of the system in the embodiments described above should not be understood as a requirement for such separation in all embodiments, and it should be understood that the software components and systems described in general may be combined in a single software and/or hardware product or packaged in a plurality of software and/or hardware products.

Specific embodiments of the subject matter of the present invention have been described above. Other embodiments are within the scope of the following claims. For example, the acts specified in the claims may be performed in a different order and still achieve the desired results. As one example, the processes depicted in the accompanying drawings do not necessarily require the specific order shown or the sequential order to achieve the desired result. In some cases, multitasking and parallel processing may be preferred.

Management and measurement

In some embodiments, the controller is a group of sensors and circuits that perform control, measurement, and monitoring functions of power management systems. The controller may be, for example, the power management system 104 described with reference to Fig. 1.

In some embodiments, the control functions include turning on and off the entire power management system, turning on and off certain sections of the power management system configured to supply power to certain target areas of the volumetric medium, and regulating the amount of energy supplied to certain areas of the volumetric medium.

In some embodiments, the control functions include control of a dynamic adjustment circuit.

In some embodiments, the monitoring functions include any combination of the following: assessing the operability and proper functionality of the entire heating system, assessing the operability and proper functionality of specific parts and sections of the heating system, performing fault detection in the entire heating system, performing fault detection of specific parts and sections of the heating system, notifying the user or users of the system of the fault, notifying the maintenance crew or repair crew of the fault.

In some embodiments, detecting a fault means any combination of the following: detecting any electrical faults, detecting any faults in the heating function, detecting any faults in the connecting strip, detecting damage in the bulk medium (including in cases where the heating system is functioning properly and is not damaged). Connecting strips in the present disclosure may also be referred to as "strips" or, in some cases, simply as "lines". A connecting strip comprises, for example, the structural layers described above with reference to Figs. 19 and 23-27F. As described below, in some embodiments, the connecting strips may include a plurality of conductive paths, such as a detection line and a carrier line. In the context of the present document, the term "carrier line" refers to a conductive path within the connecting strip that carries a current used to heat the bulk medium. A detection line is a separate conductive path configured to periodically or continuously carry a smaller current used to detect faults in the carrier line or the connecting strip as a whole.

In some embodiments, electrical faults include, but are not limited to: input and output power, voltage, current in any stage of the power management system, which have levels that are outside the established intervals. In some embodiments, electrical faults include temperature values of circuits, devices or components of the power management system, which are higher or lower than expected during normal operation of the heating system. In some embodiments, electrical faults include input and output impedances in any stage of the power system, which have levels that are outside the established intervals.

In some embodiments, malfunctions of the heating function include, without limitation: overheating of any region of the volumetric medium compared to normal operation of the heating system, underheating of any region of the volumetric medium compared to normal operation of the heating system. In embodiments in which the heating system is an anti-icing system, malfunctions of the heating function may also include any of the following: incomplete clearing of any region of the volumetric medium from ice, freezing or refreezing of precipitation on the volumetric medium during or after the implementation of deicing and anti-icing operations.

In some embodiments, the tie strip failures include any of the following: temperatures at one or more locations on or near the tie strips and on the bulk medium that are higher or lower than expected during normal operation of the heating system, a tie strip being cut off at any location, a short circuit in the tie strip (between the track and the shield or in the track itself (check track wording)), a short circuit between the tie strip and the bulk medium, a short circuit and an open circuit at the input connector of the tie strip, an open circuit in the tie strip, delamination in the tie strip structure, burning of sections of the tie strip, delamination between the tie strip and the bulk medium, peeling of the tie strip from the bulk medium, mechanical damage such as dents, holes, impacts, cuts, folds, burrs caused by events such as hail, lightning strike, improper handling of the tie strip by a maintenance crew or other personnel, walking on or stepping on the connecting strip by maintenance crews or other personnel, static discharge, corrosion on the connecting strip, the occurrence of corrosion or the formation of oxide films between the connecting strip and the bulk medium, or between the electrode/connector and the connecting strip, or between the electrode/connector and the bulk medium.

In some embodiments, the measurement functions include the use of all sensors used to provide input and feedback to the controller, such as voltage, current, power, forward power, reflected power, voltage standing wave ratio (VSWR), time domain reflectometry (TDR), temperature, and icing sensors.

In some embodiments, some or all of the elements of the controller are distributed in the power management system. In some embodiments, some or all of the elements of the controller are installed in such a way that they are independent of the rest of the control system. In some embodiments, these elements are located in separate special housings.

In some embodiments, two or more elements of the controller are independent of each other and are designed in such a way that a failure of the controller functions will occur only in the event of a simultaneous failure of at least two of these elements. In such embodiments, due to the independence of the controllers with respect to each other, the reliability of the controller is increased, and the reliability required from each of these elements to meet the requirements of the controller is lower, which in some cases facilitates and simplifies their design, implementation and integration. This is especially advantageous in those areas of application where the safety and reliability of the controller are critical or adjustable, in particular in the case of installing a heating system on an aircraft.

In some embodiments, two or more subsystems that perform monitoring functions are made independent of each other to ensure that the reliability and safety requirements are met. In some embodiments, two or more subsystems that perform measurement functions are made independent of each other to ensure that the reliability and safety requirements are met. In some embodiments, two or more subsystems that perform control functions are made independent of each other to ensure that the reliability and safety requirements are met. In some embodiments, any combinations of control, measurement, and monitoring subsystems are made independent of each other to ensure that the reliability and safety requirements are met.

In some embodiments, two identical sensors are used at some sensor locations. In such embodiments, both sensors may be connected to the same monitoring subsystem and may transmit data to it. For example, each of them may be connected to each individual monitoring subsystem and implemented in such a way that these monitoring subsystems are independent of each other, each of them may be connected to two or more monitoring subsystems implemented with the ability to function independently of each other.

In some embodiments, two independent sensors are used to collect information about a similar area, and their independence can be achieved by using sensors of different types and/or placing them at least at some distance from each other while maintaining the ability to monitor the same area or collect equivalent information. In such embodiments, both sensors can be connected to the same monitoring subsystem and can transmit data to it, each of them can be connected to each individual monitoring subsystem and implemented in such a way that these monitoring subsystems are independent of each other, each of them can be connected to two or more monitoring subsystems implemented with the ability to function independently of each other.

In some embodiments, any combination of the control, measurement and monitoring subsystems of the controller is configured to optimize the reliability and safety of the implementation of their most important functions. In the case of a heating system used to remove icing and prevent icing of an aircraft, in some embodiments, such functions may include a combination of the following: detecting any faults in the heating system and notifying the pilot about them, detecting electrical faults in the power management system and notifying the pilot about them, detecting any faults in the connecting strips, detecting any faults associated with heating in the power management system and the volumetric environment and notifying the pilot about them.

In some embodiments, in which the heating system is used to de-icing and prevent icing of the aircraft, the controller is further optimized to perform a check that the critical surfaces of the aircraft after de-icing are free of freezing or frozen precipitation and contaminants. Contaminants may be freezing rain, snow, ice, or any other material that may adhere to the skin of the aircraft and interfere with its proper operation.

In some embodiments, the arrangement of the controller and the connecting strips on the volumetric medium is designed and optimized to ensure that they operate together. In such embodiments, the connecting strips can be arranged on the volumetric medium in such a way as to create regions of interest at selected locations. Such regions can be, for example, regions that are designed to remain colder than the rest of the volumetric medium when the heating system is activated, or regions that can be primarily subject to the phenomenon of refreezing (for example, with ongoing freezing either from frozen precipitation or from melted contaminants flowing along the surface of the volumetric medium) when the heating system is operating or after it has been deactivated. In such embodiments, the sensors of the controller can be arranged in such a way that they can collect information about these regions and allow an assessment of whether the heating system is functioning properly or whether the volumetric medium is subject to the phenomenon of freezing or refreezing. In some embodiments, the volumetric medium may be locally modified in some of these regions to ensure that they are colder than other regions of the volumetric medium when the heating system is operating, or that they are primarily subject to the phenomenon of refreezing (for example, by adding relatively small features such as edges and ridges so that melt water can accumulate and stagnate over the colder region to facilitate refreezing). In some embodiments, such regions are selected so that they can be easily observed by the user of the heating system (for example, in the case of an anti-icing system of an aircraft, so that they are easily visible to the pilot from the cockpit or flight deck of the aircraft) and so that this user can conclude whether the icing of the volumetric medium has been eliminated based on visual observation of said regions.

In some embodiments, in which the heating system is used to remove ice and prevent icing of an aircraft, the controller is further optimized to perform a check to see if specific areas contain freezing or frozen precipitation and contaminants. Such areas may include: horizontal and inclined upper surfaces on which precipitation falls vertically and nearly vertically, the upper surface of the wing and horizontal stabilizer.

In some embodiments, some monitoring functions are performed using analysis methods that involve the use of machine learning, computer vision, and artificial intelligence technologies for data collected by the measurement subsystems. As part of such analysis methods, in some embodiments, the technologies may involve learning using data empirically collected during tests conducted on heating systems, and learning and improvement may occur continuously using data collected by the installed heating systems.

In some embodiments, the controller is configured to use a timer that provides time information such as the time the heating system was activated, the time that has passed since the last activation of the heating system, and the time that has passed since the last deactivation of the system. In some embodiments, the information from the timer can be used in combination with information from the measurement subsystems to analyze how to ensure that the controller performs its intended functions.

As shown in Fig. 37A, in some embodiments, a flight deck display and warning system may be provided. This system may have a plurality of indicators that inform the pilot of the system status. For example, an "ON" indicator may be illuminated when power is supplied to the system, a "WARM" indicator may be illuminated when some or all of the required temperature sensors detect a level of 15 °C or higher. For example, an "OK" indicator may be illuminated when some or all of the required temperature sensors indicate a level of 15 °C or higher for at least 15 minutes. An "OVHT" indicator may be illuminated if an overheating condition is detected, for example, any temperature sensor reaches a temperature of 150 °C or higher. A "System Fail" indicator may be illuminated for various reasons, indicating a possible system failure. For example, if the system has been in the "ON" state for a specified time (e.g., 25 minutes) without reaching at least the "WARM" state. In another example, the "System Fail" indicator may light if the system is in the "ON" state and has been in the "OVHT" state for more than 10 seconds. The above temperature and time values are given as an example and they can be changed or adjusted without departing from the scope and spirit of the present invention.

Fig. 37B illustrates an alternative example of a flight deck indicator showing the system operating status for a "DE-ICE" system state and an "ANTI-ICE" system state. In the example illustration, the flight deck indicator may indicate whether the system is in an "OFF" state, "GROUND DE-ICE" state, "GROUND ANTI-ICE" state, or "FAULT" state. In some embodiments, a separate indicator may be provided for each region of the aircraft or region of interest.

Fig. 37C shows an embodiment example in which the flight deck indication of Fig. 37B can be located in the cockpit of the aircraft. In the example of Fig. 37C, indicated by the dotted frame, the flight deck indication is located in the upper right corner of the upper flight deck of the aircraft.

In some of the above embodiments, the controller measurement subsystems may include one or more wireless sensors, such as one or more wireless temperature sensors or one or more wireless icing sensors, which may be configured to transmit data to a central receiver via a wireless data transmission network. This may reduce the need for laying additional sensor wires and providing access to various physically remote locations on the volumetric environment. The wireless sensors may be powered from the connection strip 1900 using a direct electrical connection, such as by using a low-voltage, low-current DC bias existing in the connection strip 1900, or be powered directly in the form of an alternating current passing through the connection strip 1900. Alternatively, the wireless sensors may be powered without a direct connection to the connection strip 1900, such as by using near-field electromagnetic radiation through an antenna or an inductor.

Temperature measurement

In some embodiments, the controller measurement subsystems include temperature sensors. The temperature sensors can be used to perform a point measurement or to measure parameters such as maximum, minimum, average temperature or a temperature map for a certain area, for example, using a sensor matrix that contains a plurality of sensors by which information about the area can be obtained.

In some embodiments, temperature sensors may include sensors that are any of the following types: thermocouples, resistive temperature detectors (RTDs), thermistors, fiber optic sensors, infrared sensors. Thermocouples may be used to measure temperature by measuring a change in voltage. Thermocouples are inexpensive, easy to implement, and have a wide measurement range. The signal magnitude is on the order of tens of millivolts, potentially requiring significant noise reduction to make an accurate measurement in the presence of electromagnetic interference. Resistive temperature detectors (RTDs) may be used to measure temperature by measuring a change in resistance in the sensor. These elements are typically made of platinum and have very high accuracy. This may involve making measurements in a four-clamp manner or using short leads, such as by making a local voltage measurement that is then converted to a digital signal. Thermistors are similar to RTDs in that they both calculate temperature based on a resistance measurement. Thermistors have the added benefit of having a high base resistance, making the lead resistance potentially negligible. Fiber optic sensors are typically based on fiber Bragg gratings. These gratings reflect light at a specific wavelength. As the temperature changes, the reflected wavelength changes predictably, allowing the temperature to be calculated. Since each grating reflects only a small band of wavelengths, many sensors can be incorporated into a single fiber optic element and measurements can be made with a single instrument. The fiber optic elements themselves are very small in diameter, ~0.1 mm, but can have a total length of several meters or tens of meters. Since the measurement is optical, protection against radio frequency interference must be provided.

In some embodiments, the temperature sensors are located on the bulk medium in a manner as described previously herein. In some embodiments, the temperature sensors may be located at a large distance from each other, under the casing of the bulk medium, or in both of these locations, such as in accordance with the lumped capacitance model, which assumes that the temperature of the solid should be spatially uniform within a volume for which the Biot number Bi is sufficiently small (e.g., Bi < 0.1), where the Biot number is defined as , where k is the thermal conductivity of the solid, h is the convective heat transfer coefficient from the solid to the surrounding medium, and L is the characteristic dimension of the volume. The lumped capacitance model may be a particularly useful model because in volumes in which the Bi number is sufficiently small, the temperatures of the bulk medium may be considered to be approximately uniform, which allows for a reduction in the number of sensors installed on the bulk medium, thereby reducing the complexity of the system, the cost and labor required for installation. Such methods may be particularly effective on bulk media that have high thermal conductivity, such as aluminum alloys, which typically make up the skin of an aircraft, where the Biot number remains sufficiently small over a relatively large area to justify the use of a limited number of temperature sensors and measurement points. In some embodiments, the temperature sensors may be located on the bulk medium, for example at specific locations, such as hot spots, cold spots, refreezing points, among other points. Hot spots may be locations selected so that they are relatively hotter than other locations on the bulk medium when the heating system is activated. Hot spot sensors may be used to perform general controller functions and may be used to detect overheating events on the bulk medium or connecting strips. Cold spots may be locations selected so that they are relatively colder than other locations on the bulk medium when the heating system is activated. Cold spot sensors may be used to perform general controller functions and may be used to detect underheating events on the bulk medium or connecting strips. Refreeze points may be locations selected so that freezing or refreezing events are more likely to occur there earlier than other locations on the bulk medium when the heating system is activated or after it is deactivated. Refreeze point sensors may be used to perform general controller functions and may be used to detect refreezing or underheating events on the bulk medium or connecting strips. Other points may be located in other areas of interest, such as those previously listed in this description.

In some embodiments, the arrangement of the connecting strips on the volumetric medium may be optimized so that the points described above are designated areas selected based on parameters such as ease of access, ease of installation, or ease of visual observation for the user of the heating system. For example, as shown in Fig. 33, the visibility from the flight deck for the pilot of the aircraft is limited by the line of sight 3302. As a result, the pilot does not see the section (3304) of the aircraft and sees the section (3306) of the aircraft. In some embodiments, a refreeze point or cold spot may be selected that is located within the visible section (3306) of the aircraft to ensure that the pilot can visually inspect it.

Fig. 33 further illustrates an example of an overlay display of the wing temperature when the system is active. The location 3308 on the wing may be an example of a cold spot selected or designed to be visible to the pilot and to be monitored to check the anti-icing protection before takeoff. For example, as shown in the figure, the location 3308 is correlated with an area of relatively low temperature (as indicated by the yellow gradient) compared to the majority of the wing (as indicated by the red gradient) within the heating pattern provided by the heating elements (such as the connecting strips described herein).

The locations of cold and/or hot spots may be designed, for example, by arranging heating strips (e.g., tie strips) on the surface of the aircraft in a pattern that provides a heating pattern on the aircraft skin with locally colder or warmer areas of the skin compared to the rest of the aircraft. For example, tie strips may be arranged in a pattern to locally provide a lower (or higher) power density (greater distance between wires), or selected tie strips may operate at a lower (or higher) power density in areas of higher (lower) thermal mass, or locally adjust the power output to create a heating pattern that provides cold/hot spots in the desired locations.

In some embodiments, at least two independent sets of temperature sensors may be used to improve the reliability of the critical functions of the controller by adding redundancy to its measurement subsystems. In some embodiments, independence may be achieved by adding two identical temperature sensors at each designated sensor location. In some embodiments, independence may be achieved by adding two different temperature sensors (e.g., sensors from different manufacturers or different types) at each designated sensor location. In some embodiments, independence may be achieved by adding two temperature sensors at locations sufficiently distant from each other to reduce the likelihood of simultaneous failure of both sensors, and at the same time located sufficiently close to each other to monitor equivalent parameters. In some embodiments, independence may be achieved using any combination of these methods. In some embodiments, the sets of independent sensors may send information to one monitoring subsystem, or may send information to a set of independent monitoring subsystems, each of which is configured to work with an independent set of sensors, or they may all send information to a set of at least two independent monitoring subsystems.

In some embodiments, the temperature measurement may be performed using one or more temperature sensors (or temperature sensing elements) that are an integral part of the connection strip, for example, instead of using temperature sensors or in addition to temperature sensors that are separately located on the bulk medium. Examples of temperature sensors are described in more detail above in the "Temperature Measurement" section. For example, a temperature sensor may be attached to the connection strip or to a nearby detection line (detection lines are described in more detail below) and may be either short-circuited or open-circuited when the temperature exceeds a predetermined threshold. A short-circuited or open-circuited circuit may be detected elsewhere, such as at an input connector or in a power management system (e.g., system 104). This allows the temperature to be determined at the location of the temperature sensor.

In some embodiments, the temperature sensors may be arranged in parallel in the matrix. For example, the parallel sensors may form a matrix of parallel overheating or undertemperature sensors arranged in the form of a thermostat control loop. The operation of the thermostat control loop is based on a hysteresis control method used to maintain the temperature of the system, for example, the heating system 100 according to Fig. 1, in a given range, for example, above the minimum temperature Tmin and below the maximum temperature Tmax, using information from the temperature sensor.

In some embodiments, the temperature-sensitive elements may be arranged in series in the matrix. For example, the temperature-sensitive elements may be arranged along the connection strip 1900, such as attached to the connection strip or to a nearby detection line, or along a separate cable strip to provide an overheat shutdown if the temperature becomes too high at any point in the series configuration.

In some embodiments, temperature sensing elements, such as periodic thermistors of different ratings, may be arranged in parallel such that when a particular temperature sensing element along a line becomes excessively hot, an analog value may be determined and decoded indicating not only the excessive heating of the connecting strip, but also the specific location where the fault has occurred along the connecting line.

In some embodiments, temperature measurement may be performed by using tracks on flexible circuits, by using additional detection lines running inside the connecting strips and along the carrier lines - detection lines acting as wires leading to and from temperature sensors, implemented inside the connecting strips -, by using additional detection lines and sensors implemented inside the detection strips installed independently of the connecting strips, or by implementing temperature sensors directly in the connecting strips with the carrier lines, for example, in a configuration of periodic capacitors, parallel plate capacitors, inductors in the form of a track, or a combination thereof.

In some embodiments, temperature may be measured as a function of time. For example, temperature changes may be measured and recorded at regular measurement intervals and stored as vectors representing temperature changes with respect to time, rather than static temperature measurements. Measuring temperature with respect to time may allow for more complex mathematical analysis, such as determining a rate of change (e.g., a time-dependent derivative) or a total heat output (e.g., calculating an integral). In such embodiments, the controller may perform any of a variety of estimates, including estimates of the current deicing status based on time information associated with temperature changes. As a specific example, in response to the temperature readings measured by the temperature sensors in the region of 0°C, the controller can determine that the energy supplied by the heating system of the bulk medium is converted into the latent heat of fusion and, thus, the execution of the de-icing operation continues, and, further, when the temperature readings measured by the sensors increase after being in the region of 0°C, the controller can determine that the de-icing operation is completed since the energy supplied to the bulk medium is converted into an increase in temperature, and not into the latent heat of fusion after the frozen contamination melts on the bulk medium. In other words, the time point at which the bulk medium is cleared of ice can be determined when the temperature versus time graph has been relatively flat (e.g., had a zero slope) for a given period of time, followed by a period of positive slope.

In some cases, as will be described below in the Icing Detection/Measuring section, temperature can also be measured as a function of time and the de-icing status can be assessed in a similar manner.

Fig. 40 shows graphs of impedance and temperature versus time on a connecting strip. As shown in graph 4000, the temperature readings fluctuate around a fixed value (10°C) during the deicing operation (from approximately 07:00 to 07:30), and then, when the deicing operation is completed, the temperature readings increase (starting from approximately 07:30).

In addition, in embodiments in which the bulk medium is made of high-temperature conductive materials (e.g., aluminum), a lumped capacitance thermal model may be used as a basis for assessing the deicing status of the system. The controller may also use the lumped capacitance thermal model to determine the locations of any cold spots on the bulk medium, as well as to determine the temperature of the cold spots. This may reduce the overall number of sensors required, facilitate more efficient placement of sensors, including placement of sensors under (i.e., instead of on top of) the aircraft skin, or both, by utilizing the thermal conductivity of the bulk medium.

Icing detection/measurement

In some embodiments, the controller measurement subsystems include icing detectors or sensors. The term "icing detection" refers to a method for recognizing freezing or frozen precipitation or contaminants, including, but not limited to, snow, ice, and melted snow or similar forms of frozen precipitation accumulated on a surface.

In some embodiments, ice detection is used to determine the need for deicing of a structure, track the progress of deicing, and monitor subsequent ice accumulation after deicing.

In some embodiments, icing detection is achieved by using a transducer or a plurality of transducers to monitor acoustic parameters of the structure, including, but not limited to, a damping ratio, a resonant frequency, and a frequency response. In some embodiments, icing detection is achieved by observing changes in polarized light. In some embodiments, using variable polarization, changes in incident unpolarized light can be observed after it interacts with ice. In some embodiments, changes in incident polarized light are observed. In some embodiments, changes in the intensity of reflected light can be used to detect ice formation. In some embodiments, icing is detected on a surface on which snow/ice accumulates using a sensor or a plurality of sensors. When snow or ice accumulates on a surface, they cover an aperture of a sensor that signals the presence of ice. In some embodiments, infrared radiation from surfaces can indicate the presence of ice. This includes, but is not limited to, a change in the emissivity of the surface, as well as calculating the surface temperature to determine that conditions are favorable for ice formation. In some embodiments, icing detection may be achieved using sensors mounted on critical surfaces. When freezing or frozen precipitation accumulates on the sensors, it results in a measurable change in electrical impedance. In some embodiments, the icing sensors operate using the fact that the presence of ice near the connecting strips will affect the electromagnetic fields surrounding the lines, causing a detectable effect on the frequency domain response and/or the time domain response of the connecting strips to an electrical signal. These changes may be measured and used to determine the presence of ice on the structure. In some embodiments, the presence of ice may be predicted based on a temperature gradient in the structure or on the rate of change of temperature, which may be measured using temperature sensors as described above. In some embodiments, any of the sensors described herein may be mounted on the surface of the structure.

In some embodiments, the icing sensors are located on the volumetric medium in the same way as the temperature sensors can be located, as was previously described in this description. In some embodiments, the icing sensors can be located on the volumetric medium, for example, in certain places, such as hot spots, cold spots, refreezing points, among other places. The hot spot sensors can be used to perform general functions of the controller and can be used to detect an excessive heating phenomenon on the volumetric medium or connecting strips. The cold spots can be selected so that they are relatively colder than other places on the volumetric medium when the heating system is activated. The cold spot sensors can be used to perform general functions of the controller and can be used to detect insufficient heating on the volumetric medium or connecting strips. The refreezing points can be selected so that freezing or refreezing phenomena occur there with a higher probability earlier than in other places on the volumetric medium when the heating system is activated or after its deactivation. Refreeze point sensors may be used to perform general controller functions and may be used to detect refreeze or underheating events on bulk media or connecting strips. Other points may be located in other areas of interest, such as those previously listed in this description.

In some embodiments, the arrangement of the connecting strips on the bulk medium may be optimized such that the points described above represent designated areas selected based on parameters such as ease of access, ease of installation, or ease of visual observation for a user of the heating system.

In some embodiments, at least two independent sets of ice sensors may be used to improve the reliability of the critical functions of the controller by adding redundancy to its measurement subsystems. In some embodiments, independence may be achieved by adding two identical ice sensors at each designated sensor location. In some embodiments, independence may be achieved by adding two different ice sensors (e.g., sensors from different manufacturers or different types) at each designated sensor location. In some embodiments, independence may be achieved by adding two ice sensors at locations that are sufficiently distant from each other to reduce the likelihood of a simultaneous failure of both sensors and at the same time located sufficiently close to each other to monitor equivalent parameters. In some embodiments, independence may be achieved using any combination of these methods. In some embodiments, the sets of independent sensors may send information to one monitoring subsystem, or may send information to a set of independent monitoring subsystems, each of which is configured to work with an independent set of sensors, or they may all send information to a set of at least two independent monitoring subsystems.

In some embodiments, the controller measurement subsystems include one or more capacitive sensors. One or more capacitive sensors, alone or in combination with other sensors, such as temperature sensors, can be used to distinguish ice taps. For example, a circuit board, such as a flexible printed circuit board (or flexible printed circuit board), which includes an array of one or more capacitive sensors, can be placed on the surface of the bulk medium to measure changes in capacitance readings on the surface, such as due to the presence of ice or water. As another example, the capacitive sensors can be placed under a cover layer (e.g., a film instead of paint) of the bulk medium.

In some embodiments, the temperature on the connection strip 1900 can be determined based on impedance measurements, which can be similarly measured as a function of time, for example, by comparing the impedance measurement values with a database of reference frequency response graphs at different temperatures. For example, the data can be collected in a test system that records the frequency response for impedance as a function of ambient temperature. The controller can then use the recorded data to determine the temperature values of the connection strip based on the impedance readings.

In some such embodiments, the connecting strip 1900 includes a material (materials) that is characterized by significant and predictable changes in impedance with changes in temperature, which facilitates the use of impedance measurements to estimate the temperature of a target region of a bulk medium. For example, the connecting strip 1900 can be partially made using dielectric materials or conductors for which the permittivity or conductivity can predictably change with a change in temperature, which leads to a local change in impedance in a target region of a bulk medium. For example, the connecting strip 1900 can be made using one or more acrylic adhesives, silicone adhesives, ethylene vinyl acetate adhesives, polysulfide sealants, polyurethane sealants, Mylar, PTFE, FEP, Kapton or epoxy-based materials.

For example, to determine the current temperature of a specific connection strip, the controller may measure the impedance value of the specific connection strip and then compare this impedance value with the temperature values in a lookup table. As another example, the controller may perform an impedance measurement and then calculate (for example, based on a mathematical relationship between impedance and temperature) the temperature based on the measured impedance value. As a specific example, an acrylic adhesive material may be used to make the lower dielectric layer of the strip that separates the connection strip from the bulk medium.

Fig. 41 is a three-dimensional graph of the dielectric constant of an exemplary acrylic adhesive material. Fig. 42 is a graph of the dielectric constant of an exemplary acrylic adhesive material.

As shown in Fig. 41, the permittivity (ε _r ) of the acrylic adhesive material changes with temperature (°C). In particular, the permittivity determines the characteristic impedance of the system including the bonding strip and the bulk medium. As the temperature of the bonding strip changes, the permittivity changes accordingly. This, in turn, leads to a change in the impedance of the system.

In some embodiments, the impedance may be measured as a function of time, and the deicing status may be determined based on the impedance measurements using a detection circuit similar to temperature measurements, since impedance typically changes with a change in temperature. In particular, the time at which the bulk medium is deiced may be determined when the impedance versus time graph has been relatively flat (e.g., had a zero slope) for a given period of time, followed by a period of positive or negative slope. As shown in graph 4500 in Fig. 40, the impedance readings fluctuate around a fixed value (5.7 ohms) during the deicing operation (from approximately 07:00 to 07:20), and then, when the deicing operation is completed, the impedance readings increase (starting at approximately 07:20).

Electrical equipment

In some embodiments, the controller includes control, measurement and monitoring subsystems used to measure electrical parameters and performance. Such parameters include voltage, current, input and output power at any output impedance at any stages of the heating system, including its power management system, internal connections, cable routing, connectors and electrodes.

In some embodiments, the controller uses and analyzes the collected electrical parameter data to evaluate the health of the heating system and its components, to control the amount of energy supplied to target areas of the volumetric medium to ensure proper heating, to notify the user of the system of any faults and errors, and to record the collected data for further diagnostics from the user of the system or a maintenance crew.

In some embodiments, the controller may verify that all measured electrical parameters are within expected ranges to perform its control and monitoring functions.

In some embodiments, the output and input power in any of the stages of the power management systems are measured simultaneously so that the controller can evaluate the power levels and the efficiency of these stages. For example, by monitoring the power level and efficiency (input power divided by the power supplied to the heating elements), faults in the system can be detected and faults in the de-icing system can be notified. For example, this can be used to determine that insufficient power supplied to the load will result in incomplete de-icing.

In some embodiments, the controller measures and uses the voltage-to-current ratio at the input and output of any stage of the heating system. For example, in some stages of the heating system, changes in the electrical elements on the load side cause a change in the voltage-to-current ratio in the stages on the supply side of the electrical system, and detection of these changes allows for detection of remote faults on the load side and determination of performance indicators.

Frequency domain analysis is commonly used to analyze cables and high frequency systems, for example by determining the magnitude and phase of the input impedance of a circuit over a range of frequencies. This information can be used to evaluate the performance of a heating system and, in embodiments where the system includes coupling strips (which function as transmission lines), to evaluate the characteristic impedance, propagation constant, termination load, and length of the coupling strips.

For example, for a transmission line with a known characteristic impedance, with an open-circuit termination, the input impedance can vary from 0 at lengths that are odd multiples of a quarter wavelength of the traveling signal, to Z ₀ at lengths that are multiples of a half wavelength.

This analysis can be performed from a single point or, if access to both ends of the cable is possible, a "2-port" measurement can be performed, which analyzes the transmission and reflection of the signal as it passes from one port to the other.

Frequency domain measurements are most often made with a network analyzer, an instrument that transmits a series of frequencies at high levels, calculates impedance from the voltage/current relationship, interpolates, and displays the data.

In addition, tools can be used to determine if there have been any changes to the transmission line system. In a complex electrical system where cables may run over long distances and be difficult to access, transmission line analysis is an important tool to check for cable breaks or other unwanted changes.

Cuts and other direct damage to the connecting strips and other cables in the heating system can be detected by performing impedance measurements. Additional data can also be determined, such as a complete or partial cut of the connecting strip or cable. An example of an error that can be detected is a change in length. For example, if a connecting strip or cable is broken, it becomes shorter (and its termination load may change) and its total impedance changes according to the following formula:

Faults can also be detected when the termination load differs from the expected value, for example if a connecting strip that normally has an open termination load is shorted, or if a connecting strip that normally has a shorted termination load is cut or peeled off and the termination load becomes open.

It is important to note that passive monitoring of the operating power management system provides the ability to determine the impedance at the operating frequency. Therefore, the diagnostic functions described in the remainder of this document can be performed during operation.

While using a network analyzer involves sending sinusoidal signals through the device being measured to obtain its frequency response, making it an active measurement method, passive monitoring involves monitoring signals passing through the device (such as voltage and current signals) during normal operation to calculate its impedance. Since it only provides information based on operating signals and conditions, it does not provide as much information as using the full frequency range. However, it can still be used to monitor faults. It can also operate continuously, including while the heating system is running.

The implementation of passive monitoring includes 3 main elements.

- Interface:

The interface between the power system and the monitoring system must be carefully designed. For example, it is important that excess energy, such as energy intended for de-icing, does not flow into the monitoring system.

- Division:

Another critical element for the system is the calculation of impedance based on voltage and current (e.g. V/I). It must be accurate and fast enough, and include phase information.

- Signal conversion

Once the impedance signal has been calculated, it is typically converted into a form that is most commonly used in monitoring subsystems, such as using an analog-to-digital converter.

Passive monitoring is a valuable tool for protecting the overall system by detecting faults in real time and providing protection against any damage to the power system that may be caused by the fault.

In some embodiments, the controller may alternate the operation of the circuit analyzer system with the supply of power to the connecting strips. For example, the controller may periodically switch the power supplied to the connecting strips, connecting the circuit analyzer to check for faults. The power flow to the connecting strips may be resumed after the circuit analyzer receives a measurement. Then, the circuit analyzer may be turned off to avoid damage to it from power signals. In some embodiments, the circuit analyzer may be configured to rotate to perform measurements on different connecting strips. For example, the controller or control system may alternately turn off the power flow in different connecting strips when measurements are being performed on this strip using the circuit analyzer. In this way, neighboring connecting strips may still perform some heating of the surface of the aircraft near the connecting strip on which measurements are being performed using the circuit analyzer.

In some embodiments, the network analyzer may be configured to operate using a different signal frequency range than the power supply system. For example, the power supply signals may be supplied in the range of 100-450 MHz, while the network analyzer may be configured to measure the impedance of the coupling strips using test signals in the range of 1-10 MHz. A low-pass filter may be provided between the input/output of the network analyzer and the power supply to prevent damage to the network analyzer by power signals and to ensure that the impedance of the coupling strips is measured without the need to terminate heating.

In some embodiments, the controller additionally uses time domain reflectometry techniques to perform its functions. Time domain reflectometer (TDR) is a study of reflections in a transmission line. It is typically used to locate faults in cables that are very long or otherwise difficult to access. Its main difference from the previously discussed techniques is that it operates in the time domain. This means that it measures the time it takes for a signal to reach the end of a cable or patch strip and return to its point of entry. It is, for example, an effective tool for measuring parameters such as the length of a transmission line or patch strip, or the characteristic impedance. Time domain reflectometry is an important complement to frequency domain analysis because it can provide values for parameters that are difficult to derive from a frequency plot.

Fig. 34 shows an example of an implementation of time domain reflectometry, illustrating, for example, how open circuits, short circuits, and impedance mismatches can be detected using time domain reflectometry on a connection strip attached to an aluminum panel.

Thus, time domain reflectometry allows to characterize and localize breaks, faults or defects in a transmission line, cable or connecting strip. For example, for a cable made of homogeneous materials, the propagation velocity of an electrical signal can be measured. Using this propagation velocity, the distance from the measurement point using time domain reflectometry can be measured and any disturbance, fault, change in termination or transformation as local impedance changes can be detected.

Time domain reflectometry involves using a very fast pulse generator to send a signal to the system being measured. Key parameters of the pulse, including the time it takes to transition from low to high voltage, are tuned for each specific system under test and for the specific measurement task to collect the required data. The pulse is then measured with an oscilloscope. Specialized pulse generator/sample scope instruments optimized for periodic measurements can be used, but specialized equipment is not always required. The time domain representation can be reconstructed from the frequency domain. Using the inverse Fourier transform, the output of a network analyzer can be transformed into an approximation of the expected time domain behavior.

Because time domain reflectometry can characterize and locate breaks in a transmission line, it can be used to detect shorts, opens, line delaminations, and other transmission line faults in a heating system, such as its cables and splice strips.

Fig. 35A shows a comparison of two of our transmission lines measured using time domain reflectometry. In one line, a connector is installed at 2 meters, which is visible in the graph as a large change in impedance localized in a narrow region. The same technology can be similarly used to detect deformation of transmission lines or connecting strips, short circuits, and delamination of the transmission line from the bulk medium. In some embodiments, the controller automatically analyzes the results. With proper signal processing and the use of advanced analysis technologies (e.g., using machine learning, computer vision, deep learning, artificial intelligence, and other data-driven methods), it is possible to compare the measurement results in real time with a stored reference value to detect, characterize, and quantify changes, and interpret the graphs to determine parameters including impedance, termination, and length.

It can be shown that the elements of the heating system, such as its cables and connecting strips in embodiments in which they are included, have geometric and material properties that depend on the temperature. As an example, thermal expansion and contraction can affect the geometric shape of the transmission lines and connecting strips. In addition, it can be shown that the conductivity, permittivity and magnetic permeability of the materials included in the structure of the connecting strips can vary depending on the temperature. The previous sections described how faults can be detected by changing the impedance measured at different points in the system. In addition to detecting changes in the physical structure of the connecting strips or volumetric media, the deicing status can also be assessed. The change in impedance depending on the temperature can be calculated, modeled or measured empirically. In some embodiments, it is possible to measure the impedance and the change in impedance of the connecting strips over time to determine their temperatures as an additional way to perform the function of the controller.

Another useful indicator may be the rate of change of the measured impedance. It can be shown that during its phase change, the material (in this case, ice that melts to form water) will continue to absorb energy, but its temperature will not change (in this case, remaining at 0 °C until completely melted). In some embodiments, the controller is configured to measure the impedances of the connecting strips and use this property to better perform its functions, including determining whether deicing is ongoing or complete.

- Detection of damage and transformations in a volumetric environment

In embodiments in which the connecting strips are installed on the volumetric medium in such a way that the volumetric medium can be considered as part of the geometry of the transmission line (for example, when installing the connecting strip on an aluminum cladding in such a way that the aluminum cladding is one of the planes of the resulting strip formed by the combination of the connecting strip and the aluminum cladding), these methods can be used to detect changes, transformations and damage in the volumetric medium, even when the connecting strip itself is not affected. For a structure with sufficient coverage of the connecting strips of the entire volumetric medium in which these lines are laid back to an electrical system, such as the heating systems described in this document, sections of the volumetric structure can be analyzed and checked for possible damage at centralized measurement points.

In some embodiments, changes in the structure of the volumetric medium may be considered and analyzed as geometric changes in the transmission lines formed by the connecting strips connected to the volumetric medium. For example, a dent may change the geometry of the volumetric medium by changing the characteristic impedance of the transmission line in a certain region.

When installed on the skin of an aircraft, the system described herein may provide the ability to detect damage to the skin and structure. Such damage detection may be performed autonomously using control and measurement circuits built into the aircraft or using specialized diagnostic equipment delivered by the maintenance crew to the required locations in the aircraft. Currently, this type of damage is typically detected by visual inspection, which is a labor-intensive and error-prone process. In addition, in-flight damage detection is limited to events large enough that the crew can detect them without the aid of any diagnostic system.

In the case of an aircraft with a composite skin, transmission lines can be embedded into the composite layers of the skin material (e.g. by taking advantage of the lightning shield and adding conductive lines into another layer to form embedded micro strips or bands), allowing for damage detection, including delamination of the composite material.

In some embodiments, the system may include separate detection lines configured to detect faults in the connecting strips. For example, the connecting strips may be prone to a particular type of fault - delamination, in which the connecting strip is at least partially separated from the bulk medium. In some such embodiments, the detection line may be configured to be more sensitive to certain faults. In some embodiments, the detection lines may be included in the carrier line in the connecting strip 1900.

For example, as briefly indicated above, the carrier line is a conductive path within the connecting strip (see 1900 in Fig. 19 and 23-27F) that conducts the current used to heat the bulk medium, while the detection line is a separate conductive path configured to detect faults in the carrier line or the connecting strip as a whole. The detection line is configured to periodically or continuously carry a current (AC or DC) used to detect faults in the carrier line or the connecting strip as a whole. The current in the detection line is typically less than the current in the carrier line under normal operating conditions (e.g., in the absence of a fault). For example, the detection line can be added to the connecting strip similar to the connecting strip 1900 shown in Fig. 19. The detection line can be added to the same layer of the connecting strip as the carrier line (e.g., conductive path 1904 in Fig. 19), or to a separate layer relative to the carrier line.

A current sensor, which can be configured to detect changes in the current flow in a wire or circuit, can be used by the system to determine that a higher current than usual is flowing through the detection line and, therefore, delamination is detected. In particular, the system can perform delamination detection based on threshold values. For example, in a properly laminated line, the current measured on the detection line will be relatively low. However, in a (partially) delaminated line, the current will be higher than the current threshold value. The threshold value can be selected to ensure the ability to detect a given delamination length (e.g. 10 cm) while maintaining a sufficient height to avoid false alarms during normal operation of the 3900A or 3900B connecting strip.

Additionally or alternatively, a two-port network sensor-analyzer may be used in the system, in which the first port with a reference ground is connected to the carrier line, and the second port with a reference ground is connected to the detection line. Such a network sensor-analyzer may be configured to quantitatively evaluate the coupling between the detection line and the carrier line by measuring S-parameters (for example, the S21 parameter) of the two-port sensor network at one or more selected frequencies. Then, if the S21 parameter is above a specified threshold, delamination may be detected.

In some embodiments, the heating system may include any of a plurality of self-changing components that may facilitate detection of system failures, including delamination. In particular, the connecting strip 1900 may be designed in such a way that in a particular failure mode it changes to an easily detectable failure configuration. The connecting strip 1900 may be designed in such a way that this occurs early enough to allow rapid detection before any undesirable consequences of the failure occur, for example, for the bulk medium 1902.

As one example, the dielectric separator between the conductive layer 1904 and the conductive shielding layer 1906 can be made of one or more predetermined materials such that the geometric shape of the dielectric separator changes and that it loses its insulating properties when it begins to melt after its temperature exceeds a threshold temperature, for example, when heat accumulates on the connecting strip 1900, locally on a section of the connecting strip 1900 that has peeled off from the bulk medium 1902, due to the peeling off of the section of the connecting strip, supplying heating signals to its own conductive shielding layer (instead of the bulk medium) and, thus, self-heating this detached section of the connecting strip. A change, for example due to an electrical short, of the dielectric separator between the conductive layer 1904 and the conductive shielding layer 1906 results in a sharp change in the characteristics and input impedance of the connecting strip, based on which any delamination can be easily detected, for example, using a current sensor or an impedance sensor. For example, a sharp change in impedance can be an increase or decrease in the impedance of the connecting strip by one or more orders of magnitude compared to the impedance of the connecting strip during normal (without faults) operation.

For example, in the case of deicing the exterior surface of an aircraft, since the heating system typically operates in the temperature range of 50°C to 60°C, the threshold temperature may be set to a value that is above the upper limit of the normal range and well below the dangerous temperature (e.g., the ignition temperature of a fuel tank), such as 130°C. In this example, polysulfide-based materials are examples of materials suitable for use in the manufacture of a dielectric separator.

As another example, the conductive layer 1904 can be made of one or more predetermined materials such that the conductive layer 1904 loses its electrical conductivity as the temperature increases, for example, decomposes to an open state, thereby providing direct detection of delamination. In this example, copper, aluminum and alloys are suitable materials for use in making the conductive layer.

As another example, the lower dielectric layer can be made of one or more predetermined materials whose permittivity can vary significantly with temperature, resulting in detectable changes in impedance that can be used to determine a fault or to enable accurate temperature measurements using impedance measurements. In this example, acrylic adhesives, silicone adhesives, ethylene vinyl acetate adhesives, polysulfide sealants, polyurethane sealants, Mylar, PTFE, FEP and Kapton are suitable materials for use in making the lower layer.

In some embodiments, the conductive layer 1904 may be designed to be less sensitive to certain aspects of the system compared to other aspects. For example, the conductive layer 1904 may be designed to be relatively temperature-independent in terms of the impedance, cross-sectional area, or both for the conductive layer 1904. Thus, any fault in the system, such as delamination, which causes a significant change in impedance, will be easily distinguishable from normal operating variations of the system.

In particular, in order to achieve the desired sensitivity of the conductive layer 1904 in these embodiments, different construction materials, different adhesive materials and associated connection methods, different geometric design, such as different cross-sectional dimensions, or different termination configurations may be considered. For example, water-based adhesives are characterized by abrupt changes in impedance near 0 ° C, while alcohol-based adhesives, such as ethylene vinyl acetate (EVA), are characterized by more consistent or stable changes in impedance. Epoxy resin also has relatively stable dielectric properties.

- Frequency domain analysis to detect mechanical changes in a volumetric environment

Impedance changes can also be used to detect mechanical changes (e.g. dents or cracks) in the aircraft skin or other bulk medium. For example, impedance changes can be detected after impacts to the structure both on and off the connecting strips. This was demonstrated using an impact test rig. A 1.2 kg indenter was dropped onto the panel from a height of 2.8 m. It was chosen to produce a 4 mm dent 25 mm from the nearest fastener attaching the aircraft skin to a structural member, such as a wing rib. The observed changes were small enough that they did not cause a system failure, but large enough to be detected.

Fig. 35B shows the normalized active component of the impedance immediately before and after the impact. The expressions "near end fairing", "near connector" and "in the middle" indicate impacts on the connector strip at the indicated location. The expressions "in between" and "far" indicate impacts between the two branches of the connector strip and at a distance (~18 cm) from the nearest connector strip. As shown in the figure, a jump in impedance is visible after the impact.

As shown in Fig. 35B, a relatively small jump (~5%) in impedance is observed after the impact. It can be detected both for impacts on and off the connecting strip. Since the impedance change is detectable even for impacts away from the connecting strip, it can be used to detect impacts, including when they occur between lines. Since the lines in our system will cover a large part of the aircraft surface, they can be used to monitor the structure and detect mechanical changes (e.g., dents or cracks).

- Frequency domain analysis for cable fault detection

In some embodiments, frequency domain analysis graphs can be used to detect any cable faults that may be present in the heating system 100, such as delamination of the connecting strip 1900; and can also be used to detect mechanical changes (such as dents or cracks) in the aircraft skin or other volumetric medium. In particular, advanced graph analysis technologies can be used, including graph transformation technologies (such as the Fourier transform) and machine learning technologies (such as neural networks), to extract, from the frequency response graphs or data obtained from the frequency response graphs, or from both, features or characteristics based on which facts of cable faults or mechanical changes in the volumetric medium can be detected. In general, different features or characteristics can indicate different types of cable faults and mechanical changes in the volumetric medium.

For example, the features or characteristics may include minimum or maximum values of resistance or theta, as well as the associated frequency value with which these minimum or maximum values are associated. As another example, the features or characteristics may include information about the pattern of resonant peaks, including, for example, the dominance of resonant peaks, the distance between peaks, and the consistency of the frequency spacing from peak to peak.

Fig. 43 shows graphs of frequency responses of a functional coupling strip (for example, an undamaged coupling strip) and a faulty coupling strip installed on a bulk medium. In this example, delamination can be detected as a specific type of cable fault based on determining whether a uniform decrease or increase in corresponding values of resonant peaks, for example, resonant peak 4310, occurs in a given frequency range. As shown in graph 4300, the values of the resonant peaks for a functional coupling strip decrease uniformly. However, as shown in graph 4350, for a non-functional (for example, delaminated) coupling strip, the values of the resonant peaks can first decrease, then increase, and then decrease again.

In some embodiments, a fault such as a short circuit, an open circuit, or a delamination of a cable (e.g., a patch strip) can be detected by comparing a measured impedance versus frequency of a particular cable with data indicating an expected impedance versus frequency pattern for an undamaged (e.g., healthy) cable. For example, a spectrum analyzer or a time domain reflectometry device can be used to measure an impedance pattern versus frequency or time domain for a particular cable. The measured impedance pattern versus frequency or time domain can be compared with an expected impedance pattern versus frequency or time domain for a similar cable that does not have the fault (as shown, for example, in graph 4350). In the frequency domain example, changes in features or characteristics of the resonant peak pattern of the measured impedance pattern versus frequency compared to the expected impedance pattern versus frequency can be used to identify fault(s) in the cable.

- Application of time domain reflectometry to detect mechanical changes in a volumetric medium

Since indentations and other mechanical changes in the bulk medium represent localized deformation of the bulk medium, they can lead to a localized change in the characteristic impedance of transmission lines mounted on the bulk medium. Thus, time domain reflectometry is well suited for detecting and localizing mechanical changes in the bulk medium.

Fig. 36 shows examples of time domain reflectometry on two different designs of a connection strip. The red lines represent the dent test panel and the blue lines represent the base panel. Time domain reflectometry reveals abrupt changes in impedance along the dented connection strip, which appear as impedance fluctuations around its normal value for the undented panel. With this information, it is possible to further localize the dents to specific areas of the cable. In this way, the location of the fault in the underlying structure can be determined. This information can be difficult to obtain using only the frequency response, since the average characteristic impedance along the length of the connection strip is approximately the same. However, time domain reflectometry allows us to find localized discontinuities.

In one embodiment of the heating system, time domain reflectometry measurements made on the connecting strips covering the volumetric medium, in combination with the analysis of the obtained data (e.g., using the advanced methods listed above), can be used to map the condition of the skin of the volumetric medium, the condition of the structural components and the operability. They can be used either as a diagnostic tool for maintenance and repair, or as a real-time monitoring tool.

In embodiments of an electric anti-icing system using connecting strips for heating a volumetric medium, a plurality of connecting strips are powered by the same high-frequency source. This embodiment may include additional cabling so that the AC power source is physically located remotely from the connecting strips in question. In these embodiments, fault detection and de-icing assessment are still possible, as described above. In essence, a single monitoring system in the AC source is capable of monitoring the performance of all attached connecting strips. However, in another embodiment, additional monitoring means may be placed at the input of each connecting strip. Each connecting strip may be considered as a parallel element with additional cable connections used as series elements in the circuit. This circuit will also be determined by the geometrical parameters and material parameters of its construction.

In some embodiments, multiple AC sources may be combined to supply power to one or more tie strips, as described above. In the same manner as described above, this will allow one controller subsystem to detect faults among one or more AC sources and one or more tie strips. However, it is also possible to provide separate monitoring means for each AC source, which will allow the source of the fault to be isolated to one element of the system. In this embodiment, redundant AC sources could be installed so that the fault detection system is able to activate the redundant elements to compensate for the fault while simultaneously completing de-icing.

Some embodiments of the electric anti-icing system may include a distributed or integrated circuit between the AC source and the tie strips. This circuit may be passive (containing only inductors, capacitors, resistors and transformers). On the other hand, this circuit may be active (containing transistors, logic gates or other elements, such as in the case of active impedance control circuits). In an embodiment in which this circuit is active, it may be used to detect faults and evaluate de-icing. In embodiments in which multiple tie strips are powered from a single or combined AC source, the distributed active circuit may isolate faults to a single tie strip element by deploying separate monitoring means for each tie strip element. In addition, if additional redundant tie strip elements are installed, the distributed active circuit may supply power to other tie strips to reduce the effects of a fault in one tie strip and complete de-icing. Such a distributed circuit may interact with AC sources or any "power side" circuits either via cables or by using known wireless communication protocols, or by controlling the voltage, current or impedance of the system. For example, in one embodiment, such a distributed circuit may use an electrical or electromechanical switch to disconnect any coupling strips in which the impedance is outside the normal range. Such disconnection may be detected by a monitoring system in the AC source, and it is also ensured that the faulty coupling strips are not energized to prevent possible further damage to the system. In another embodiment, energy may be supplied to areas of greater icing by coordinating the operation of other sensors (e.g., temperature sensors, icing sensors) with such a distributed circuit.

In embodiments of the present invention in which a plurality of connecting strips are attached to the same volumetric medium, faults in nearby connecting strips can be detected by transmitting signals to one connecting strip. All connecting strips attached to the same volumetric structure can be characterized by some level of electromagnetic coupling. By placing a transmitter on a separate connecting strip (e.g., an AC power supply, a circuit analyzer, a device for performing time domain reflectometry, etc.) and a receiver, such as an oscilloscope, on a separate connecting strip, it is possible to capture induced signals. This effect can be used to verify that the coupling is within the expected range. If the coupling coefficient is outside the expected range, this may indicate a fault. For example, in one possible embodiment, a poor electrical connection of a connecting strip to a volumetric structure can lead to increased coupling with other connecting strips. This will also lead to insufficient heating for the purpose of removing icing. By monitoring the induced signal in other connecting strips, this error can be detected.

In some embodiments, as similarly described above, time domain reflectometry graphs can be used to facilitate detection of tie strip delamination, such as by using graph mining techniques to analyze certain features depicted in or otherwise extracted from the time domain reflectometry graphs.

In addition to detecting defects in bonding strips or detecting dents in bulk media using technologies similar to those described above, time domain reflectometry or frequency domain analysis can be used to detect the presence of various contaminants, such as water or ice, on the bulk media and to determine the type of contaminants present on the bulk media.

It should be noted that, in the context of the present document, the term "electrically connected" includes the case where the components are connected to each other by means of an object having any electrical function, as opposed to a "direct connection" in which two electrical components are directly connected to each other (e.g. by means of a wire or printed conductor without any additional intermediate components such as resistors, capacitors, inductors, etc.). Furthermore, references to a first component as electrically connected to a particular terminal of a second component are not intended to include an electrical path passing through the second component itself. For example, an electrical connection of a capacitor to a gate terminal of a transistor may include the case where this electrical connection passes through other objects or components that have an electrical function, but does not include the case where the electrical connection passes through another terminal (e.g. source/drain) of the transistor itself to the gate of the transistor.

Claims (128)

1. A system for heating the exterior of an aircraft, comprising: a series of individual heating elements located on the aircraft's skin; a sensor located on the casing at a location that corresponds to a region of relatively low temperature within the heating pattern provided by these heating elements; and a control system connected to the heating elements and the sensor, wherein the control system is configured to: control of the power supplied to the heating elements in response to the output signal from the sensor, determining, based on the output signal from the sensor, the characteristics of the aircraft skin at a specified location; comparison of the value of a characteristic with a reference characteristic and supplying power, in response to determining that the characteristic value indicates freezing at the specified location, to the heating element. 2. The system of claim 1, wherein the heating elements are connecting strips comprising a multilayer structure extending along the surface of the aircraft skin, which in combination with the aircraft skin forms a power transmission line, wherein the multilayer structure comprises: the first dielectric layer on top of the aircraft skin, a conductive layer on top of the first dielectric layer, a second dielectric layer on top of the conductive layer and a conductive shielding layer over a second dielectric layer. 3. The system according to claim 1, wherein the location comprises a structural element on the aircraft skin, designed with the possibility of maintaining the local temperature in this location at a lower level compared to the temperature of the majority of the aircraft skin with active heating elements. 4. The system of claim 3, wherein the structural element includes an arrangement of heating elements that provides less heating in a location relative to a larger portion of the aircraft skin. 5. The system according to claim 1, wherein the location comprises a structural element on the aircraft skin, designed with the ability to cause the formation of ice in this location. 6. The system of claim 5, wherein the structural element comprises a ridge, edge or wall. 7. The system of claim 1, wherein the sensor is a temperature sensor or an icing sensor. 8. A system for heating the outside of an aircraft, comprising: a series of individual heating elements located on the aircraft's skin; a sensor located on the skin at a location that corresponds to a region of relatively low temperature within the heating pattern provided by these heating elements, said location being visible from the aircraft window, and a control system connected to the heating elements and the sensor, wherein the control system is configured to control power supplied to the heating elements in response to an output signal from the sensor. 9. The system according to item 1, wherein the control system is configured to: determining, based on the output signal from the sensor, the characteristics of the aircraft skin at a specified location; comparison of the value of a characteristic with a reference characteristic and initiating, in response to determining that the value of the characteristic indicates freezing at a specified location, an indication of a freezing condition. 10. The system of claim 1, further comprising a second sensor located on the aircraft skin at a second location that corresponds to a region of relatively high temperature within the heating pattern provided by these heating elements, and the control system is connected to the second sensor, and the control system is designed with the ability to: determining, based on the output signal from the second sensor, the temperature of the aircraft skin at a second location; comparing this temperature with the reference temperature for this place and initiating, in response to determining that the temperature exceeds a reference temperature, an indication of an overheating condition. 11. The system of claim 1, further comprising a second sensor located on the skin of the aircraft at a second location that corresponds to an area of relatively high temperature within the heating pattern provided by these heating elements, and the control system is connected to the second sensor, and the control system is designed with the ability to: determining, based on the output signal from the second sensor, the temperature of the aircraft skin at a second location; comparing this temperature with the reference temperature for this place and reducing the power supplied to the heating element in response to determining that the temperature exceeds the reference temperature. 12. A system for heating the outside of an aircraft, comprising: a series of individual heating elements located on the skin of the aircraft; and a control system connected to the heating elements, wherein the control system is configured to control power supplied to the heating elements, wherein the control system comprises an impedance monitoring subsystem connected to the heating elements, wherein the impedance monitoring subsystem is configured to: monitoring the input impedance of heating elements and detect, based on the input impedance, a fault in the heating element. 13. The system of claim 12, wherein detecting a fault in the heating element comprises: obtaining the first impedance model depending on the frequency of the heating element and detecting a fault by comparing a first impedance model as a function of frequency with a second impedance model as a function of frequency, which indicates the expected impedance value without any fault. 14. The system of claim 12, wherein the impedance monitoring subsystem comprises a passive system configured to determine the impedance of the heating elements based on electrical characteristics of the heating elements in response to power signals supplied to the heating elements. 15. The system of claim 12, wherein the impedance monitoring subsystem comprises an active system configured to transmit a test signal to the heating elements and determine an impedance of the heating elements based on electrical characteristics of the heating elements in response to the test signal. 16. A system for heating the outside of an aircraft, comprising: a series of individual heating elements located on the skin of the aircraft; and a control system connected to the heating elements, wherein the control system is configured to control power supplied to the heating elements, wherein the control system comprises an impedance monitoring subsystem connected to the heating elements, wherein the impedance monitoring subsystem is configured to: monitoring the input impedance of heating elements and detection, based on input impedance, of mechanical changes in the aircraft skin. 17. The system according to claim 12, wherein the control system comprises a time domain reflectometry (TDR) monitoring subsystem connected to the connecting strips, wherein the TDR monitoring subsystem is configured to: monitoring the response of heating elements to an electrical pulse in the time domain and detection, based on the response to an electrical pulse in the time domain, of a malfunction in the heating element. 18. The system of claim 17, wherein detecting a fault in the heating element comprises: obtaining the first model of time-domain reflectometry of the heating element and detecting a fault by comparing the first time domain reflectometry pattern with a second time domain reflectometry pattern that indicates an expected time domain reflectometry pattern for the heating element without any fault. 19. The system according to claim 16, wherein the control system comprises a time domain reflectometry (TDR) monitoring subsystem connected to the connecting strips, wherein the TDR monitoring subsystem is configured to: monitoring the response of heating elements to an electrical pulse in the time domain and detection, based on the response to an electrical pulse in the time domain, of a mechanical change in the skin of an aircraft. 20. A system for heating the outer portion of a volume conductor, comprising: a series of individual heating elements located on the casing of a volume conductor; a sensor located on the casing at a location that corresponds to a region of relatively low temperature within the heating pattern provided by these heating elements; and a control system connected to the heating elements and the sensor, wherein the control system is configured to control the power supplied to the heating elements in response to the output signal of the sensor. 21. The system of claim 20, wherein the heating elements are connecting strips comprising a multilayer structure extending along the surface of the sheathing of the bulk conductor, which in combination with the sheathing of the bulk conductor forms a power transmission line, and the multilayer structure comprises: the first dielectric layer on top of the bulk conductor skin, a conductive layer on top of the first dielectric layer, a second dielectric layer on top of the conductive layer and a conductive shielding layer on top of the second dielectric layer. 22. The system of claim 20, wherein the location includes a structural element on the casing of the volume conductor, configured to maintain the local temperature in this location at a lower level compared to the temperature of the majority of the casing of the volume conductor with active heating elements. 23. The system of claim 22, wherein the structural element includes an arrangement of heating elements that provides less heating in a location relative to the majority of the sheathing of the bulk conductor. 24. The system according to claim 20, wherein the location comprises a structural element on the casing of the volume conductor, designed with the possibility of causing the formation of ice in this location. 25. The system of claim 24, wherein the structural element comprises a ridge, edge or wall. 26. The system of claim 20, wherein the sensor is a temperature sensor or an icing sensor. 27. The system of claim 20, wherein the location is visible from the window of the volume conductor. 28. The system according to item 20, wherein the control system is configured to: determining, based on the output signal from the sensor, the characteristics of the sheathing of the volume conductor at the specified location; comparison of the value of the specified characteristic with the reference characteristic and initiating, in response to determining that the value of the characteristic indicates freezing at a specified location, an indication of a freezing condition. 29. The system of claim 20, further comprising a second sensor located on the sheathing of the volume conductor at a second location that corresponds to a region of relatively high temperature within the heating pattern provided by these heating elements, and the control system is connected to the second sensor, and the control system is designed with the ability to: determining, based on the output signal from the second sensor, the temperature of the casing of the volume conductor at the second location; comparing this temperature with the reference temperature for this place and initiating, in response to determining that the temperature exceeds a reference temperature, an indication of an overheating condition. 30. The system according to item 20, wherein the control system is configured to: determining, based on the output signal from the sensor, the characteristics of the sheathing of the volume conductor at the specified location; comparing the value of the specified characteristic with the reference characteristic and supplying power, in response to determining that the characteristic value indicates freezing at the specified location, to the heating element. 31. The system of claim 20, further comprising a second sensor located on the sheathing of the volume conductor at a second location that corresponds to a region of relatively high temperature within the heating pattern provided by these heating elements, and the control system is connected to the second sensor, and the control system is designed with the ability to: determining, based on the output signal from the second sensor, the temperature of the casing of the volume conductor at the second location; comparing this temperature with the reference temperature for this place and reducing the power supplied to the heating element in response to determining that the temperature exceeds the reference temperature. 32. The system of claim 21, wherein the control system comprises an impedance monitoring subsystem connected to the connecting strips, wherein the impedance monitoring subsystem is configured to: monitoring the input impedance of heating elements and detect, based on the input impedance, a fault in the heating element. 33. The system of claim 31, wherein detecting a fault in the heating element comprises: obtaining the first impedance model depending on the frequency of the heating element and detecting a fault by comparing a first impedance model as a function of frequency with a second impedance model as a function of frequency, which indicates the expected impedance value without any fault. 34. The system of claim 21, wherein the control system comprises an impedance monitoring subsystem connected to the connecting strips, wherein the impedance monitoring subsystem is configured to: monitoring the input impedance of heating elements and detection, based on the input impedance, of a mechanical change in the sheathing of a bulk conductor. 35. The system according to claim 21, wherein the control system comprises a time domain reflectometry (TDR) monitoring subsystem connected to the connecting strips, wherein the TDR monitoring subsystem is configured to: monitoring the response of heating elements to an electrical pulse in the time domain and detection, based on the response to an electrical pulse in the time domain, of a malfunction in the heating element. 36. The system of claim 35, wherein detecting a fault in the heating element comprises: obtaining the first model of time-domain reflectometry of the heating element and detecting a fault by comparing the first time domain reflectometry pattern with a second time domain reflectometry pattern that indicates an expected time domain reflectometry pattern for the heating element without any fault. 37. The system according to claim 21, wherein the control system comprises a time domain reflectometry (TDR) monitoring subsystem connected to the connecting strips, wherein the TDR monitoring subsystem is configured to: monitoring the response of heating elements to an electrical pulse in the time domain and detection, based on the response to an electrical pulse in the time domain, of a mechanical change in the cladding of a volume conductor. 38. A system for heating the exterior of an aircraft, comprising: a series of individual heating elements located on the skin of the aircraft; wherein the heating elements are connecting strips comprising a multi-layer structure extending along the surface of the skin of the aircraft, which in combination with the skin of the aircraft forms a power transmission line, wherein the multi-layer structure comprises: the first dielectric layer on top of the aircraft skin, a conductive layer on top of the first dielectric layer, a second dielectric layer on top of the conductive layer and a conductive shielding layer over the second dielectric layer, and wherein the conductive layer of at least one of the connecting strips comprises a detection line and a carrier line, wherein the detection line is located inside the connecting strip for detecting faults in the carrier line or the connecting strip, a control system connected to the heating elements, wherein the control system is configured to: control of the power supplied to the heating elements; and detecting, based on one or more signals received over a detection line, a fault in one or more connecting strips. 39. The system of claim 38, wherein the detection line comprises one or more capacitors configured to measure temperature based on a change in impedance of the detection line. 40. The system of claim 38, wherein the connecting strip comprises one or more self-changing components configured to fail in a predetermined manner indicating a fault in the connecting strip. 41. The system according to claim 1, wherein the control system is configured to determine the status of the de-icing operation by: measuring the temperature indicated by the sensor over a period of time; determining that deicing is complete in response to determining that the slope of the temperature graph remained constant at a temperature of approximately zero degrees Celsius for a period of time and then the temperature began to increase. 42. The system of claim 1, wherein the control system is configured to measure a frequency response for the impedance of the connecting strip and estimate a temperature of the connecting strip based on the measured frequency response for the impedance.