KR20160073303A - Wireless charger and wireless power receiver - Google Patents

Abstract

According to the present invention, disclosed are a method and a structure in a wireless charging system, to reduce electromagnetic radiation by shunting an in-phase current flowing in a wireless power transmission unit and a wireless power receiving unit. Moreover, a design methodology for enabling a wireless charger to uniformly supply power in various positions and loads is disclosed. According to one embodiment of the present invention, a wide charging area for simultaneously charging mobile devices, high efficiency in various positions and directions of the mobile device and uniform power are provided, and a small amount of electromagnetic radiation occurs in transmitting and receiving coils. The wireless charger comprises: a transmitting coil; a protection device; and an impedance matching circuit.

Description

Wireless charger and wireless power receiver

This disclosure relates to wireless power transfer (WPT), and more particularly to a device for a wireless charging system capable of charging multiple mobile devices simultaneously. The mobile device is charged using the magnetic field coupling of a transmitting and a receiving resonator.

Several development groups are studying WPT systems for spatial freedom of energy transmitters and receivers. Design, theoretical analysis, geometric optimization and a common optimization approach using spiral coils with multiple spirals or multiple turns for combined coils in various geometries have been addressed in the prior art . Optimization of the power induction of the coil without using shielding elements and without a wireless charging system has also been analyzed in the prior art. A method of providing a uniform magnetic coupling of the transmit coil and the receive coil, based on the size of the transmit coil, which is much larger than the receive coil size, is also described in the prior art. It has already been demonstrated that a uniform magnetic coupling of the transmit coil and the receive coil allows power to be transmitted with a uniform power transmission efficiency (PTE).

Wireless power transmission technology has been developed to enable convenient charging of the embedded battery of a mobile or wearable electronic device or the power supply of the device. Wireless chargers with wireless power transmission technology typically operate in the 100kHz to 100MHz range.

A mobile device that can conveniently be charged wirelessly has a battery pack and a receive coil fixed inside. When the mobile device is placed close to the transmit coil of the wireless charger, it is charged. An induced electromotive force is formed in the receiving coil by the magnetic field formed in the transmitting coil, and the power caused by the electromotive force charges the mobile device.

The most common wireless power charging scheme is a star topology network. The wireless charger interacts with one or more mobile devices for simultaneous charging. The wireless coupling is made through a power transmission resonator and a power receiving resonator, and a magnetically coupled induction coil connects the power transmitting resonator with the power receiving resonator. The power source is connected to the power transmitting resonator, and the power receiving resonator is connected to the rectifier to convert the receiving side energy from AC to DC.

A drawback of a wireless charger that can have a wide charging range and can be charged regardless of the position or orientation of the power receiving resonator is that a large amount of conducted and radiated electromagnetic radiation is emitted. Wireless chargers with a wide charging range can use high switching voltages and high currents in the primary coil, which can have a large amount of EMI and can have a negative impact on other electronic products due to EMI .

The present application provides a wireless charger and a wireless power receiver capable of reducing electromagnetic radiation emissions by shunting in-phase currents flowing in a wireless power transmitter and a wireless power receiver in a wireless charging system to a protection device.

The wireless charger according to some embodiments may include a transmission coil, a conductive protection element, and an impedance matching circuit connecting the transmission coil and the power source, the impedance matching circuit being connected in parallel with the transmission coil, And at least two capacitors that connect to the ground of the power source and the protection element.

In one embodiment, at least one tab of the transmitting coil may be connected to the ground of the protection element and the power source.

In one embodiment, the at least one tab may be connected to a ground of the protection element and the power source through a galvanic or capacitive connection.

In one embodiment, the capacitive coupling may be formed by lumped capacitor elements or by a mutual capacitance between the at least one tab and the protection element.

In one embodiment, the at least one tap may comprise an intermediate tap of the transmitting coil.

In one embodiment, the magnetic resonance imaging device may further include a magnetic resonance absorption element positioned between the transmission coil and the protection element.

In one embodiment, the resonant frequency of the MR resonant device may be equal to the frequency at which the electromagnetic radiation emitted by the transmitting coil is a peak.

In one embodiment, the protection element may be produced using at least one of a copper material and a ferrite material.

In one embodiment, the spacing between the conductive turns of the transmitting coil may decrease as it is further away from the central portion of the transmitting coil to the outer edges.

In one embodiment, the radius of curvature of the transmission coil turn is maximum at the outer periphery and may decrease towards the central portion of the transmission coil.

A wireless power receiver according to some embodiments may include a receive coil, an impedance matching circuit that couples the receive coil and the load, and the impedance matching circuit is coupled in parallel with the receive coil, To the ground of the load.

In one embodiment, a protective element comprised of a conductive material may be located between the receiving coil and the load.

In one embodiment, the protection element may be produced using at least one of a copper material and a ferrite material.

In one embodiment, at least two inductors may be connected in series between at least two of the at least two series capacitors and the load, and a point between the at least two series capacitors and the at least two inductors, And at least two capacitors connected to the ground of the load.

In one embodiment, a rectifier may be connected to the impedance matching circuit.

In one embodiment, the receive coil includes a plurality of conductive turns, and the outer dimensions of the receive coil can be maximized within the effective surface of the wireless power receiver.

In some embodiments, the wireless power transmission unit may include a transmit coil, a power source, a protection element, and an impedance matching circuit that couples the transmit coil and the power source, The circuit may include at least two capacitors coupled in parallel with the transmit coil to couple the transmit coil to ground and the protection element of the power source. The wireless power receiving unit may include a receiving coil, a load, and an impedance matching circuit for connecting the receiving coil and the load. The impedance matching circuit is connected in parallel with the receiving coil to connect the receiving coil to the ground of the load At least two capacitors that are connected in series. The wireless charging system may include a wireless power transmitter and a wireless power receiver.

1 is a diagram illustrating an equivalent circuit of a wireless charging system according to an embodiment.
2 is a diagram of a parameter model and a dimension of a transmission coil and a first protection element according to an embodiment.
3 is a diagram illustrating a wireless power receiver and its internal components in accordance with one embodiment.
FIG. 4 is a view illustrating a structure of a wireless charging system according to an embodiment viewed from the side.
5 is a diagram illustrating a structure of a wireless charging system viewed vertically and horizontally when a wireless power receiving unit is located on a wireless power transmitting unit according to an embodiment.
6A and 6B are diagrams showing a current distribution when the wireless power receiving unit is located at the center of the transmission coil in FIG. 6A and in the outer periphery of the transmission coil in FIG. 6B according to an embodiment.
7A and 7B illustrate a method of reducing the total thickness of a wireless power transmission unit according to an exemplary embodiment. In FIG. 7A, when the first protection device is made of a copper material, And Fig.
8 is a view showing an enlarged view of a position where a transmitting coil is connected to a ground and a first protective element of a power source according to an embodiment and connected thereto.
9A and 9B are diagrams showing spectra for measurements of in-phase voltage at the transmit coil according to whether shunt capacitors are coupled to ground and the first protective element of the power source, according to one embodiment. FIG. 9A shows a case in which no connection is made, and FIG. 9B shows a case in which a connection is made.
10A and 10B illustrate an equivalent circuit showing that a center tap of a power source ground and a transmission coil are connected according to an embodiment is shown in FIG. 10A as a galvanic connection, and in FIG. 10B as a capacitive Lt; RTI ID = 0.0 > capacitive connection. ≪ / RTI >
FIGS. 11A and 11B are diagrams showing asymmetric structures in FIG. 11A and symmetrical structures in FIG. 11B in connection with the type of transmission coil structure according to an embodiment.
FIG. 12 is a graph illustrating through comparison that the EMI radiation level is reduced using an intermediate tap connection of a transmission coil according to an embodiment.
13 is a circuit for connecting the capacitor 2C _2P to the ground of the load in the wireless power receiving unit according to one embodiment.
14A and 14B, the case where the capacitor 2C _2P is not connected to the ground of the load in FIG. 14A and the case where the capacitors 2C _2P , C _3P and the ferrite bead L _2S in FIG. Fig. 8 is a diagram showing a spectrum of measured values of voltage and current in the receiving coil when connected to ground; Fig.
15A-15C illustrate a self-resonant absorbing element positioned between a transmit coil and a first guard element for reduction of the EMI radiation level, in accordance with one embodiment. FIG. 15A is an oblique view from above, FIG. 15B is a top view, and FIG. 15C is a side view.
16 is a graph comparing the EMI radiation with and without a magnetic resonance absorber in the power transmitter according to an embodiment.
17A and 17B are graphs showing the correlation between the impedance of the wireless power transmitter and the correct implementation of the hybrid impedance matching circuit and the false implementation.
18 is a diagram illustrating an experimental result of a prototype of a wireless power transmission unit and a wireless power reception unit according to the position of the wireless power reception unit according to an exemplary embodiment.
19 is a flowchart of a method of designing a wireless power transmission unit according to an embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present disclosure may be embodied in many different forms and is not limited to the embodiments described herein. In order that the present disclosure may be more fully understood, the same reference numbers are used throughout the specification to refer to the same or like parts.

The terms used herein may be used to describe various components, but the components should not be limited by terms. Terms are used only for the purpose of distinguishing one component from another.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when a part is "connected" to another part, it includes a case where a part is in a state capable of performing data communication with another part and signal transmission / reception.

Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

The accompanying drawings may be schematically illustrated to illustrate embodiments, and some dimensions may be exaggerated for clarity. Similarly, a substantial portion of the figures may be expressed arbitrarily.

As used herein, the term " module " should be interpreted to include software, hardware, or a combination thereof, depending on the context in which the term is used. For example, the software may be machine language, firmware, embedded code, and application software. As another example, the hardware may be a circuit, a processor, a computer, an integrated circuit, an integrated circuit core, a sensor, a micro-electro-mechanical system (MEMS), a passive device, or a combination thereof.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. Although the terminology used in this application selects the general terms that are currently widely used, taking into account the functions in this disclosure, it may vary depending on the intentions of the artisan, the precedent, or the emergence of new technology. Also, in certain cases, there may be a term selected arbitrarily by the applicant, in which case the meaning thereof will be described in detail in the description of the corresponding invention. Accordingly, the terms used in this disclosure should be defined based on the meaning of the term rather than on the name of the term, and throughout the present disclosure.

The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

The embodiments described herein and the accompanying drawings are for the purpose of describing the disclosure through some of the various embodiments of the disclosure, and the disclosure is not limited to the embodiments described herein and the accompanying drawings.

As used herein, a wireless power transmission unit may include a wireless charger and a power source, and a wireless power receiving unit may include a receiving coil, an impedance matching circuit, and a load. The wireless charger may include an impedance matching circuit, a transmit coil, and a protection element. The wireless charger can be a separate device that can be connected to or disconnected from a power source. For example, for wireless charging, the wireless charger can be connected to a power source.

The wireless power receiver may represent an electrical, electronic, battery operated mobile or other device. The load may be a battery or battery pack of a mobile device or other device. The wireless power receiving unit can be charged by receiving power formed by the magnetic field coupling of the wireless power transmitting unit and the wireless power receiving unit. The wireless power receiver may comprise a " wireless power receiver " and a load. The wireless power receiver may include a receive coil and an impedance matching circuit. The wireless power receiver may be a separate device that can be connected to or disconnected from the load. For example, a wireless power receiver may be coupled to a load to charge the load.

In the present specification, a protection element connected to the ground and the transmission coil of the power source in the wireless power transmission unit is referred to as a " first protection element ", and a protection element for protecting the internal components in the wireless power reception unit is referred to as a "Quot;

Refers to an impedance matching circuit connected between a power source and a transmitting coil in a wireless power transmitting unit and a " second impedance matching circuit " refers to a matching circuit connected between a load and a receiving coil in a wireless power receiving unit Refers to an impedance matching circuit.

In one embodiment, to charge the battery of the mobile device, the user may place the battery directly on the wireless charger or place the mobile device on the wireless charger. Therefore, the size of the wireless charger, specifically the power transmitting resonator, is very important. Larger power transmitters can accommodate greater transmit power and can increase the number of mobile devices being charged at the same time. For example, a user may connect a battery or mobile device with a wireless power receiver, and then place the battery or wireless power receiver associated with the mobile device on the wireless charger.

When the wireless power receiver is located above the wireless charger, the receive coil and the transmit coil can be coupled by magnetic flux passing through them. Therefore, the magnetic flux generated by the transmission coil structure causes a current in the reception coil, and the energy can be transmitted to the wireless power reception unit. The wireless power receiving portion may include a rectifier coupled to an output terminal of the receive coil and may include a power operating circuit including a battery charging circuit. Specifically, a rectifier may be provided to perform AC-to-DC conversion before the current induced in the receiving coil reaches the load.

In one embodiment, a wireless charging system may include a wireless power transmitter and a wireless power receiver.

In one embodiment, the impedance matching circuit of the receive coil includes at least two capacitors connected in parallel to the receive coil, which can couple the receive coil to the ground of the wireless power receiver.

The power source provides switching voltage and high current to the transmit coil. Large-scale transmit coils induce conductive and radiated electromagnetic emissions by connecting the transmit coil structure to the protection device through at least two capacitors and shunting the in-phase current flowing through the transmit coil structure, .

The impedance matching circuit of the transmission coil can define a change in the impedance seen on the transmission side according to the load of the wireless power reception unit.

In one embodiment of the transmit coil structure, the mutual inductance may be spatially set to be independent of the position of the transmit coil. The distance between the conductors of the transmitting coil decreases from the central portion of the coil to the outer perimeter. The curvature radius of the transmit coil turn may be maximum at the outer edge, and may be smaller toward the center.

In one embodiment, the center tap of the transmitting coil can be connected to the protection element and also to the ground of the power source.

In this specification, a "transmitting coil" is referred to as a "TX coil", a "receiving coil" is referred to as an "RX coil" Quot; and " wireless power receiving unit " is referred to as " RX unit ".

As used herein, the term " load " may refer to a battery or battery pack of an electronic device. To charge the battery of the electronic device, the user must place the electronic device on the surface of the wireless charger. Therefore, the size of the wireless charger can be a very important issue. When the size of the wireless charger is large, it is possible to supply a larger amount of electric power and simultaneously charge a plurality of electronic devices. Various embodiments of the present disclosure will be described in detail with reference to the drawings.

1 is a diagram illustrating an equivalent circuit of a wireless charging system according to an embodiment.

In one embodiment, an impedance matching circuit may be included in TX portion 110 and RX portion 120. Hereinafter, the impedance matching circuit of the TX unit 110 will be referred to as a first impedance matching circuit, and the impedance matching circuit of the RX unit 120 will be referred to as a second impedance matching circuit.

In one embodiment, the TX portion 110 may comprise a wireless charger 115 and a power source 111.

In one embodiment, the TX portion 110 may comprise a power source 111, a TX coil 112, and a first impedance matching circuit 113. The power source 111 may be coupled to the TX coil 112 through a first impedance matching circuit 113. _TX current I generated in the power source 111 may be converted to the current I _{COIL TX _} by a first impedance matching circuit 113. The first impedance matching circuit 113 may include at least two capacitors 2C _1S connected to the TX coil 112 and at least two capacitors 2C _1P . The parallel capacitor 2C _1P may _couple the TX coil 112 to the ground 114 of the power source and the first protective element 130. Capacitor 2C _1P is also referred to as a shunt capacitor. The series capacitor 2C _1S can _couple the TX coil 112 and the output terminal of the power source 111. The first impedance matching circuit 113 may provide optimal impedance matching between the power source 111 and the TX coil 112. [ Although FIG. 1 shows only two 2C _1S capacitors and two 2C _1P capacitors, it is easily understood by those skilled in the art that the number of capacitors can be changed according to a specific situation. The first protective element 130 is disposed below the TX coil 112 and reduces the electromagnetic radiation emitted by the TX coil 112 except for the active fill region formed by the structure of the TX coil 112 .

In one embodiment, the RX section 120 may comprise an RX coil 121, a second impedance matching circuit 122 and a load 123. The RX unit 120 may be composed of a wireless power receiver including the RX coil 121 and the second impedance matching circuit 122 and a load 123. [ The wireless power receiver including the RX coil 121 and the second impedance matching circuit 122 may be a separate device that can be coupled to or disconnected from the load 123. [ For example, a wireless power receiver may be coupled to a load to charge the load 123

In the RX unit 120, the RX coil 121 is inductively coupled to the TX coil 112 and the electromagnetic radiation emitted from the TX coil 112 induces charging currents to the RX coil 121 . The RX coil 121 may be connected to the load 123 via the second impedance matching circuit 122 and the second impedance matching circuit 122 may be connected to the series capacitor 2C _2S and the RX coil 121 And at least two 2C < 2 > _P capacitors connected in parallel to each other. The load 123 can be charged using the charging current. The parallel capacitor 2C _2P may connect the RX coil 121 to the ground 124 of the load. The series capacitor 2C _2S can connect the RX coil 121 and the output terminal of the load 123. The second impedance matching circuit 122 can provide optimum impedance matching between the RX coil 121 and the load 123. [ Although only two 2C _2S capacitors and two 2C _2P capacitors are shown in FIG. 1, it is easily understood by those skilled in the art that the number of capacitors can be changed according to a specific situation.

In one embodiment, the first impedance matching circuit 113 and the second impedance matching circuit 122 cause resonance between the TX coil 112 and the RX coil 121 to maximize the power transmission efficiency .

In one embodiment, the capacitors of the first impedance matching circuit 113 may modify the impedance of the TX coil 112 in accordance with the impedance of the load 123.

In one embodiment, the capacitors of the second impedance matching circuit 122 may be selected to be able to transform the impedance of the RX coil 121 to an optimum impedance for the load.

In one embodiment, when the RX portion 120 is positioned above the TX portion 110, the TX coil 112 and the RX coil 121 may be coupled together by a magnetic flux. Induce _{RX _} I _COIL current to the RX coil 121, as shown in Figure 1 a magnetic flux is generated in the TX coil 112, and energy can be delivered to the load 123.

In one embodiment, the first impedance matching circuit of the TX portion may include at least two shunted capacitors 2C _1P connected in parallel with the TX coil 112, and the TX coil 112 to the output of the power source 111 And at least two series capacitors (2C _1S ) connected to the terminals. The shunt capacitor may connect the TX coil 112 to the ground of the first protection element 130 and the power source 111 to shunt the same phase current flowing through the TX coil 112 to the protection element 130 shunt to reduce electromagnetic radiation emissions by TX coil 112. [

In one embodiment, the first protective element 130 may be comprised of a conductive material such as a copper material and / or a ferrite material.

In one embodiment, the 2C _1P capacitor in the first impedance matching circuit 113 of the TX coil 112 is connected in parallel with the TX coil 112 to connect the TX coil 112 and the first protection element 130 , Which allows the in-phase current to shunt and reduce parasitic EMI emissions. Due to the presence of the first protection element 130, the electromagnetic field induced by the current of the TX coil 112 can be suppressed everywhere except where the RX part 120 is located. As a result, the final electromagnetic field is concentrated around the RX unit 120 and can induce a current in the RX coil 121 of the RX unit 120. The RX unit 120 may be located in any direction in any location within the active charging area by the TX unit 110. TX coil 112 can emit electromagnetic radiation uniformly wherever RX portion 120 is in the active charging region. The active fill region is defined by the structure of the TX coil 112 and can provide a constant impedance regardless of the position or orientation of the load 123. [

In one embodiment, the conductive wires of the TX coil 112 may be wrapped at specific intervals between wires. The spacing between the conductive wires of the TX coil 112 may decrease as it goes away from the central portion of the TX coil 112 to the outer perimeter.

In one embodiment, the TX coil 112 may be in a helical form, but is not limited thereto. The spacing between conductive conductors may decrease as the distance from the center of the TX coil 112 increases in a radial direction.

In one embodiment, the curvature radius of the TX coil 112 turn may be maximum at the outer edges and may be smaller toward the center.

In one embodiment, the TX coil 112 may be a planar coil fabricated on a single or multiple layers of PCB. The plane coil can be composed of a set of several layers. Each layer in one set may contain turns of the same pattern. All of the layers included in one set may be interconnected by a plurality of vias and may be configured as solid conductive coils of the same thickness as the thickness of the one set.

In one embodiment, the first impedance matching circuit 113 is symmetrical to the output terminal of the power source 111, and the center point of the first impedance matching circuit 113 is connected to the ground 114 of the power source 111, Lt; / RTI >

In one embodiment, the active fill region, which is defined by the TX coil 112 and refers to a region capable of wireless fill, can maintain a constant impedance regardless of the position or orientation of the load 123 in the active fill region.

In one embodiment, the electromagnetic radiation emitted by TX coil 112 may be constant within the active fill region. The electromagnetic radiation emission by the TX coil 112 can be suppressed in a range excluding the active fill area.

The RX unit 120 may further include a rectifier connected to the output of the RX coil 121 and the impedance matching circuit 122 in front of the load 123. [ The rectifier may be configured to perform AC-to-DC conversion on the current induced in the RX coil 121.

In one embodiment, the RX coil 121 may comprise a plurality of conductive turns. The outer dimensions of the RX coil 121 may be maximized within the available surface of the RX portion 120. [ The density and structure of the turns may vary depending on the structure of the RX unit 120 and the power consumption.

The second impedance matching circuit 122 of the RX unit 120 may include at least two capacitors 2C _2P coupled to the RX coil 121 and may be configured to couple the RX coil 121 to the load which connects to 123) may include at least two series capacitors (2C _2S).

In one embodiment, a wireless charging system comprised of a TX portion 110 and an RX portion 120 may operate between a frequency range of 100 kHz and 100 MHz.

FIG. 2 is a diagram of a parameter model and dimensions of the TX coil 112 and the first protective element 130 according to one embodiment.

를 획득할 수 있다. TX 코일(112)의 구조는 아래 더 자세히 묘사되어 있다.If the coupling coefficients k and Q-factors between the TX coil 112 and the RX coil 121 do not change with respect to the relative position of the RX section 120 on the TX section 110, Constant power efficiency η and constant input impedance

Can be obtained. The structure of TX coil 112 is described in further detail below.

In one embodiment, the center of the conductive wire of the TX coil 112 may be described by the following parameter model.

는 i번째 코일 전선의 곡률 반지름이고, α는 턴 비율을 나타내는 매개변수이다. shx와 shy는 각각 제 1 보호 소자(130)의 가로 및 세로 길이를 의미한다. TX 코일(112)의 N, lx_i, ly_i 및

와 같은 차원들은 최대의 효율을 전달할 수 있는지, 그리고 RX부(120)가 있을 수 있는 위치마다 균일(uniformity)한 효율을 전달할 수 있는지 라는 기준에 의해 최적화 될 수 있다. RX부(120)에서 RX 코일(121)의 차원 및 위치는 RX부(120)의 구조적 한계에 의해서 정의될 수 있다. Here, lx _N , ly _N correspond to the outermost dimension of the TX coil 112, and lx ₁ and ly ₁ correspond to the dimension of the innermost dimension of the TX coil 112. N is the number of coil turns,

Is the radius of curvature of the i-th coil wire, and a is a parameter representing the turn ratio. shx and shy denote the transverse and longitudinal lengths of the first protective element 130, respectively. N, lx _i , ly _i of TX coil 112 and

Can be optimized by the criterion of being able to deliver maximum efficiency and deliver uniformity efficiency wherever RX unit 120 may be. The dimension and position of the RX coil 121 in the RX unit 120 can be defined by the structural limitations of the RX unit 120. [

The presence of the first protection element 130 and the RX unit 120 can reduce the inductance of the TX coil 112. The first protection element 130 does not have a large effect on the loss, but an eddy current induced in a lossy material of the RX unit 120 may dissipate energy. Therefore, the actual environment of the TX unit 110 may place a large restriction on the power transmission efficiency (PTE).

In Fig. 2, the conductive turn of TX coil 112 is wound five times, but this is only an example and may be less or more.

3 is a diagram illustrating RX unit 120 and its internal components in accordance with one embodiment.

The second protective element 301 isolates the internal components 302 and 303 of the electronic device to which the RX portion 120 is coupled from an electromagnetic radiation emission of the TX coil 112 and the RX coil 121. In one embodiment, ) Of the RX coil 121. The RX coil & For example, the internal components 302, 303 of the electronic device may be one or more microcircuits.

303 can be isolated from the electromagnetic radiation emission of TX coil 112 and RX coil 121 through second protective element 301. [

In one embodiment, the second protective element 301 may be composed of a conductive material such as a copper material and / or a ferrite material.

In one embodiment, the internal components 302, 303 can be separated from the electromagnetic radiation emission of TX coil 112 and RX coil 121 by a conductive structure, such as a battery or a battery pack.

FIG. 4 is a view illustrating a structure of a wireless charging system according to an embodiment viewed from the side. "A" means the distance from the TX coil 112 to the first protective element 130 and "h" means the distance from the RX portion 120 to the TX coil 112. The presence of the first protection element 130 and the RX unit 120 can reduce the inductance of the TX coil 112. [ The second protective element 301 described in FIG. 3 may be located adjacent to the RX coil 121 as shown in FIG. The drawing can be roughly divided into three parts. A wireless charger 115 that includes a TX coil 112 and a first protection element 130, a wireless power receiver that includes an RX coil 121 and a second protection element 301, as well as internal components 302, 303), and an electronic device including a battery. The wireless charger, wireless power receiver, and electronic device may each be separate devices. To charge the battery of the electronic device, the electronic device may be connected to the wireless power receiver and placed on the wireless charger 115. [

5 is a view illustrating a structure of a wireless charging system viewed vertically and horizontally when the RX unit 120 is positioned on the TX unit 110 according to an embodiment. The wireless charging system shows the same components to compare how each component of the wireless charging system looks when viewed vertically and horizontally. In FIG. 5, the number of conductive turns of the TX coil 112 is five, but this is only an example, and may be less or more. 5, the length of the TX coil 112 and the length of the RX unit 120 in the longitudinal direction of the TX coil 112 and the RX unit 120 are substantially similar to each other, The length and width of the wireless power receiving unit 120 may be relatively larger than the length and the width of the wireless power receiving unit 120.

6A and 6B illustrate the current distribution when the RX unit 120 is in the center of the TX coil 112 in FIG. 6A and in the outskirts of the TX coil 112 in FIG. 6B, according to one embodiment. FIG.

에 의해 정의될 수 있다. 일반적으로 TX 코일(112)의 인덕턴스 및 Q-팩터는 RX부(120)가 TX 코일(112)의 가운데에서 모서리 쪽으로 이동함에 따라 증가한다. 이는 렌츠의 법칙에 따라 설명될 수 있다. RX부(120) 표면의 와전류(eddy currents)는 TX 코일에 의해 유도된 마그네틱 플럭스를 보상할 수 있다. 와전류는 RX부(120)의 배터리, 메인 보드, 프레임 등의 전도성 표면 위를 흐를 수 있다. 대표적인 위치에 RX부(120)가 각각 위치할 때 RX부(120) 위에서의 표면 전류 분포가 도 6a 및 도 6b에 나타난다. 도 6a에서 RX부(120)(전자 디바이스와 결합되어 있다)는 TX 코일(112)의 중간 부분에 위치하고, 도 6b에서는 RX부(120)가 TX 코일(112)의 외곽 부분으로 이동해 있다. 도 6a 및 도 6b에서 RX부(120) 표면에서 어둡게 칠해진 부분은 RX부(120) 몸체 표면의 전류 밀도가 높음을 의미하고, 밝은 부분은 RX부(120)의 몸체 표면의 전류 밀도가 낮음을 의미한다. RX부(120)가 서로 다른 여러 위치에 있을 때 유도된 전류의 분포가 서로 다른 것은, RX부(120)가 TX 코일(112)의 어느 위치에 있느냐에 따라 TX 코일(112)의 인덕턴스가 달라진다는 점을 설명해 준다. RX부(120)가 TX 코일(112)의 중간 부분에 위치할 때, TX 코일(112) 중간 부분에서의 마그네틱 필드는 대부분 RX부(120)의 표면에 수직이다. 이 경우 전류 분포는 RX부(120)의 모서리를 기준으로 대칭일 수 있다.There may be a parameter change in the TX coil 112 of the TX unit 110 in accordance with the relative positional change of the RX unit 120 with the TX coil 112. [ The dependence of the coupling coefficient k on the position of the RX portion 120 depends on the TX coil 112 design parameters lx _i , ly _i ,

Lt; / RTI > Generally, the inductance and Q-factor of the TX coil 112 increases as the RX portion 120 moves from the center to the edge of the TX coil 112. This can be explained according to Lenz's law. The eddy currents on the surface of the RX part 120 can compensate for the magnetic flux induced by the TX coil. Eddy currents can flow over the conductive surfaces of the battery, main board, frame, etc. of the RX unit 120. [ The surface current distribution on the RX portion 120 when the RX portion 120 is located at the representative position is shown in FIGS. 6A and 6B. 6A, the RX unit 120 (coupled with the electronic device) is located in the middle portion of the TX coil 112 and the RX unit 120 is moved to the outer portion of the TX coil 112 in FIG. 6B. 6A and 6B, the darkened portion on the surface of the RX portion 120 means that the current density on the body surface of the RX portion 120 is high and the bright portion shows a low current density on the body surface of the RX portion 120 it means. The inductance of the TX coil 112 is different depending on the position of the TX coil 112 in which the RX unit 120 is located when the RX unit 120 is located at different positions from each other Explains the point. When the RX portion 120 is located at the middle portion of the TX coil 112, the magnetic field at the middle portion of the TX coil 112 is mostly perpendicular to the surface of the RX portion 120. [ In this case, the current distribution may be symmetrical with respect to the edge of the RX unit 120. [

At the outer portion of the TX coil 112, the magnetic field is dominated by a tangent component and a non-uniform normal component. When the RX portion 120 is located near the edge of the TX coil 112, the major portion of the magnetic flux is concentrated in the middle portion of the TX coil 112, and the eddy current density becomes less and asymmetric. This current distribution, which is manifested by the field components perpendicular to the plane of the RX portion 120, is concentrated in a smaller area than when the RX portion 120 is located at the middle portion of the TX coil 112, And the inductance of the TX coil 112 can be increased.

7A and 7B illustrate a method of reducing the total thickness of the TX unit 110 according to an embodiment. In FIG. 7A, when the first protection element 130 is made of a copper material, 130 are made of copper-ferrite materials 701, 702. FIG.

In one embodiment, the copper-ferrite material may further reduce the total thickness of the TX portion 110 (by using copper-ferrite material in FIG. 7b, it can be seen that distance A is reduced).

The isolation of the TX portion 110 from the surrounding materials is possible by using various materials when constructing the first protection element 130 as shown in FIGS. 7A and 7B. In particular, a thin ferrite film material may be used in place of other conductive materials to reduce the total thickness of the TX portion 110. A 0.5mm thick ferrite can provide enough shielding efficiency of 20dB.

Table 1 shows parameter changes of the TX unit 110 and the RX unit 120 according to the change of the first protection element 130. [ According to the results in Table 1, using a thin TX coil 112 (d = 0.1 mm) using ferrite and copper material can reduce the total thickness of the TX portion 110 to 5.7 mm. The first protection element 130 is provided at a distance a = 5 mm from the TX coil 112 and the use of only the copper material reduces the magnetic inductance L1 by 57% and the coupling factor k by 40% I can give it to you. The use of the ferrite material only at the distance of a = 5 mm from the TX coil 112 makes it possible to reduce the Q-factor by 24% as compared with the case where the first protection element 130 is not used have. Decreasing the thickness d of the TX coil 112 from 2 mm to 0.1 mm does not affect the parameter. It should be noted that the use of the first protective element 130 using only the ferrite material effectively makes the wireless charging system efficient, but the magnetic inductance of the TX coil 112 affects the external metal material (e.g., metal table) It is something to do. It is desirable to design a suitable protection element in consideration of the influence of the parameter, the total thickness of the TX portion 110, and the like, as described above.

Change of the TX and RX sub-parameters according to the change of the first protection element parameter
name No protective device for TX coils 0.1mm
Copper protection device
a = 10 mm
d = 2 mm 1mm
Copper protection device
a = 5 mm
d = 2 mm 1mm
Ferrite protection device
a = 5 mm
d = 2 mm 0.5mm
Ferrite protection device
a = 5 mm
d = 2 mm 0.5mm
Ferrite protection device
a = 5 mm
d = 0.1 mm 0.1mm copper and 0.5mm ferrite protection device
a = 5 mm
d = 0.1 mm L ₁ , u H 2.03 1.26 0.87 2.7 2.6 2.6 2.4 Q ₁ 144 164 138 110 109 108 103 k 0.25 0.18 0.15 0.27 0.26 0.26 0.26 U 32.7 25.5 17.9 29.7 28.8 28.7 27.2

8 is a graph illustrating the location of the TX coil 112 coupled with the ground 114 and the first protective element 130 of the power source 111 and showing an enlarged view of the location where the TX coil 112 is connected, FIG. Connecting the TX coil 112 to the ground 114 and the first protective element 130 of the power source according to one embodiment is accomplished by using a first impedance matching circuit 113 as shown in FIG. The capacitors 2C _1S and 2C _1P of the first impedance matching circuit 113 may be located in the region 801 of FIG.

In one embodiment, the right side view of the location where the TX coil 112 is connected to the ground 114 and the first protective element 130 of the power source shows that the capacitor 2C _1P is connected to the TX coil 112 The ground 114 of the power source is connected in parallel, and the capacitor 2C _1S connects the TX coil 112 and the power source 111 in series.

Figures 9A and 9B illustrate how a shunt capacitor can be coupled to a measured value of the in-phase voltage at the TX coil 112 according to whether the shunt capacitor is connected to the ground 114 of the power source and the first protective element 130 ≪ / RTI > FIG. 9A shows a case where no connection is made, and FIG. 9B shows a case where a connection is made. 9A and 9B, the influence of the connection of the shunt capacitor on the in-phase noise reduction can be confirmed. As shown in FIG. 1, the TX coil 112 may be connected to the ground 114 of the power source 111 and the first protective element 130 using the capacitor 2C _1P . According to the results shown in FIGS. 9A and 9B, it can be seen that in the case of FIG. 9A, where the shunt capacitors are connected, the EMI noise spectrum is reduced by at least 10 dB above the 90 MHz frequency range.

10A and 10B illustrate an equivalent circuit showing that the power source ground 114 and the middle tap 1001 of the TX coil 112 are connected according to one embodiment is shown in FIG. 10A as a galvanic connection, Lt; / RTI > The middle tap 1001 of the TX coil 112 may be connected to the first protection element 130 and the first protection element 130 may be connected to the ground 114 of the power source thereby reducing EMI radiation . A variety of connection methods including the galvanic of FIG. 10A or the capacitive connection of FIG. 10B may be used for the connection method. Through various connection methods, the in-phase current can be shunted before passing through the TX coil 112 and the parasitic radiation emission in the TX coil 112 can be weakened. The transmission of the differential output power from the power source 111 to the TX coil 112 is not affected by the various connection methods. Therefore, the PTE does not decrease.

In one embodiment, the capacitive coupling may be formed by lumped capacitor elements or by the mutual capacitance between the middle tap 1001 and the first protection element 130. [ This is represented in the circuit by C 1 _C (1002).

In one embodiment, multiple connection taps between the TX coil 112 and the first protection element 130 are formed through capacitive coupling. The Multiple Connections tab is a term to refer to when multiple tabs are used. The taps in the TX coil 112 may be more than one and may include intermediate taps of the TX coil 112.

FIGS. 11A and 11B are diagrams illustrating asymmetry in FIG. 11A and symmetry structure in FIG. 11B with respect to the type of TX coil 112 structure according to an embodiment. The structure of TX coil 112 may be based on various types, including asymmetric helical coil 1101, symmetrical helical coil 1102. In each case, a single or multiple intermediate taps 1001 can be optimally positioned for the amplitude and phase balance of the voltage at the TX coil 112 pins.

In one embodiment, the middle tap 701 of the TX coil 112 is connected to the ground of the power source 111 to reduce EMI radiation.

FIG. 12 is a graph illustrating through comparison that the EMI radiation level is reduced using an intermediate tap connection of the TX coil 112, according to one embodiment. The graph 1201 shows the case where the intermediate tap 1001 is not present in the TX coil 112. The graph 1202 shows the case where the intermediate coil 1001 is present in the TX coil 112. [ In the graph 1201 in which there is no intermediate tap 1001, one peak occurs at 100 to 120 MHz and one peak at 180 to 200 MHz, so that there are two peaks in total. In the graph 1202 where there is an intermediate tap 1001, there is one peak at 180 to 200 MHz. It can be seen that the middle tap 1001 of the TX coil 112 can reduce the EMI radiation level by at least 40 dB in the frequency range of 100 to 120 MHz.

13 is a circuit for connecting the capacitor 2C _2P in the RX unit 120 to the ground 124 of the RX unit 120 according to one embodiment. One embodiment for further reducing the EMI is to connect the capacitor 2C _2P to the ground 124 of the RX part 120 and to connect the shunt capacitor C _3P and the ferrite bead L _2S to the It can be realized through an equivalent circuit that connects as shown.

14A and 14B, the case where the capacitor 2C _2P is not connected to the ground of the load in FIG. 14A and the case where the capacitors 2C _2P , C _3P and the ferrite bead L _2S in FIG. Is a diagram showing spectra of measured values of voltage and current in RX coil 121 when connected to ground 114. FIG. This shows the effect of the connection between the short-circuit capacitor C _3P and the ferrite bead L _{2S on} the common-mode noise reduction. According to the results shown in Figs. 14A and 14B, the EMI noise spectrum can be reduced by at least 20 dB at 150 MHz and by at least 30 dB at 350 to 500 MHz.

Figures 15A-15C illustrate a magnetic resonance absorber 1501 located between a TX coil 112 and a first guard element 130 for reduction of the EMI radiation level in accordance with one embodiment. FIG. 15A is an oblique view from above, FIG. 15B is a top view, and FIG. 15C is a cross-section view. 15C is a cross-sectional view of section A-A. The magnetic resonance absorber 1501 can suppress the parasitic resonance of the TX coil 112 by absorbing all or some of the peaks of EMI radiation.

16 is a graphical comparison of electromagnetic (EMI) radiation with and without a magnetic resonance absorber 1501 in the TX section 110 according to one embodiment. The effect of the magnetic resonance absorber 1501 on EMI radiation can be confirmed. The Q-factor of the MRI absorber 1501 may affect the EMI radiation reduction efficiency, curve 1602 in the graph represents the over-damping resonance structure, curve 1603 represents the under-damping resonance structure And curve 1604 represents an optimally damping resonance structure. As can be seen from Fig. 16, the 412MHz magnetic resonance absorption element of the curve 1601 can suppress the parasitic resonance by about 20dB. The difference is indicated at 1605.

The TX portion 110 may further include a magnetic resonance absorber 1501 disposed under the TX coil 112 and may be used to reduce electromagnetic radiation emitted from the TX coil 112.

The resonant frequencies of the magnetic resonance absorbing element 1501 are adjusted to be equal to the frequencies of the peaks of the electromagnetic radiation emitted by the TX coil 112 so that the magnetic resonance absorbing element 1501 has peaks of electromagnetic radiation at resonance frequencies Can be absorbed. It is desirable to reduce or eliminate the peaks of electromagnetic radiation as they can negatively affect the internal components of the electronic device being charged. The MRI absorber 1501 may be formed in the form of a split-ring resonator, a complimentary resonance spiral, a resonance spiral, a complimentary split ring resonator, or other metamaterial structure .

17A and 17B are graphs showing the correlation between the impedance of the wireless power transmitter and the correct implementation of the hybrid impedance matching circuit and the false implementation. The maximum PTE of the inductively coupled TX coil 112 and RX coil 121 is possible at the optimal load impedance. To analyze these parameters, consider two mutually coupled induction coils with inductance L ₁ , L ₂ , intrinsic losses R ₁ , R _2, and mutual inductance M. As can be seen from FIG. 1, it can be assumed that the RX coil 121 is connected to a load having a complex impedance Z ₂ . That is, let the complex impedance of the RX coil 121 viewed from the second impedance matching circuit 122 and the load 123 be Z ₂ . The optimum impedance matching Z ₂ satisfies the resonance condition in the RX coil 121, and the maximum power transmission efficiency is expressed by Z _{2 opt} :

The figure of merit U is used in the following equation for convenience.

이다. 한편 ω 는 TX부(110) 및 RX부(120)가 동작하는 주파수이다. 수학식 4로 표현되는 최적의 Z₂ opt에서 전력 송신의 최대 효율은, Where the inductive coupling coefficient k of the coil =

to be. On the other hand,? Is a frequency at which the TX unit 110 and the RX unit 120 operate. The optimal Z < _{2 >} The maximum efficiency of power transmission in opt

to be. The input impedance of the TX coil 112 at the optimal load is

to be. As the input impedance Z _{TX _ IN _ COIL} and the optimal impedance Z ₂ are defined in equations (4) and (7), the first and second impedance matching circuits 113 and 122, It is necessary to match the impedances for the power source 111 and the load 123. [ The elements of the impedance matching circuit for the RX unit 120 can be calculated as follows using the rectifier input impedance Z _RECT .

은 RX 코일(121)에 병렬로 연결된 커패시터 C2P의 임피던스이고, Y=-1/ωC_2S는 부하(123)에 직렬로 연결된 커패시터 C_2S의 임피던스이다. 수학식 9의 값을 가지는 직렬 소자는 커패시터 또는 인덕터일 수 있다. 수학식 8에서 마이너스 근을 가지는 것은 커패시터를 임피던스 매칭 회로의 분로 소자

로 이용할 가능성을 의미할 수 있고, 여기서 X_NEG는 수학식 8에서의 마이너스 근을 의미한다. 유도된 Y값이 마이너스인 경우, 직렬 커패시터 값은 이다. Where X = -

C2P is the impedance of the capacitor is connected in parallel with the RX coil (121), Y = -1 / ωC 2S is the impedance of the capacitor C _2S connected in series to the load 123. The series element having the value of equation (9) may be a capacitor or an inductor. In Equation (8), having a negative root means that the capacitor is connected to the shunt element of the impedance matching circuit

, Where X _NEG means the minus root in equation (8). If the derived Y value is negative, then the series capacitor value is.

The criteria applicable to the serial-parallel mixing element of the second impedance matching circuit 122 in the RX section 120 are as follows.

은 직렬 임피던스 매칭, 즉 C_2P=0과 대응할 수 있다. 조건

가 아닌 경우에는 제 2 임피던스 매칭 회로(122)의 직병렬 혼합 소자가 이용될 수 있다. Condition

May correspond to a series impedance match, i.e., C _2P = 0. Condition

A serial-parallel mixing element of the second impedance matching circuit 122 may be used.

Action (operation) of the power source (111) is defined by the negative input impedance Z TX _{TX _ IN.} The first impedance matching circuit 113 of the TX coil 112 can be designed from the following equation.

로 정의할 수 있다.Where X may be a reactive component of an element coupled in parallel to the TX coil 112 and Y may be an inactive component of an element coupled in series with the power source 111. In Equation (11), the root symbols of X can determine whether the type of the elements connected in parallel is a capacitor or an inductor. In Equation (12), the value of the series element can be obtained, which may be a capacitor or an inductor. The presence of a negative root means that the possibility of using the capacitor as a parallel element of the first impedance matching circuit 113

.

식으로부터 산출될 수 있다.Where X _NEG is the negative root of (11). When the calculated Y value is negative, the value of the series capacitor is

Lt; / RTI >

를 제공한다.Equation (13) represents the maximum number of samples that can be matched with a particular TX coil 112

Lt; / RTI >

,

에 근접하여 작동할 때 만족된다. 여기서 Z_{TX _ IN}의 실수부는

가 증가함에 따라 감소하며,In one embodiment, referring to Figure 1, a mistake by the Z _{_ IN TX} unit may determine that the inverse of the impedance Z of the load _RECT 123. Increase in Z _RECT can reduce the Z _{TX _ IN.} Reduction of Z _RECT can increase the Z _{TX _ IN.} The required Z-change (Z-change) is determined by the TX impedance matching circuit 113,

,

When operating in close proximity. The real part of Z _{TX _ IN}

As shown in FIG.

As shown in Fig.

가 증가함에 따라 Z_{TX _ IN}이 감소하는 결과가 그래프 1702에서 나타나므로, 상기 검토한 대로 부등식

을 만족함을 확인할 수 있다. 도 17b를 보면, 제 1 임피던스 매칭 회로(113)가 올바르게 작동하지 않는 경우, 일 실시예에 따른 스미스 도표에서 Z_{TX _ IN}의 변화가 수직에 가까움(1702)을 확인할 수 있다. 도 17b에서

가 증가함에 따라 Z_{TX _ IN}은 증가하다가 감소하는 결과가 그래프 1704에서 보이는바

을 만족하지 않음을 확인할 수 있다. 즉 Z_{TX _ IN} 임피던스의 실수부는 증가하는

에 대하여 일정하지 않은(non-uniform) 의존성을 나타냄을 알 수 있다.When dependence on Z _RECT of the input impedance Z _{TX _ IN} of the TX part 110 in Figure 17a to the hybrid impedance matching circuit is working properly, and two examples of the time also the hybrid impedance matching circuit may not operate correctly in the 17b . Referring to FIG. 17a, it can determine a first impedance matching circuit 113 is very close to the Smith chart the change in the Z level in the _{TX _ IN} (smith chart) (1701) according to, in one embodiment, if it is functioning properly. 17A,

Increases according as Z _{TX _ IN} decreases so the results are shown in the graph 1702 which, as a review of the inequality

Is satisfied. Referring to FIG. 17b, can be found the first impedance matching circuit (113) does not work, a change in _{TX _} Z _IN at the Smith chart in accordance with one embodiment close to the vertical properly 1702. 17B

The increase is a result of the bar decreases while increases Z _{TX _ IN} 1704 As shown in the graph,

Is not satisfied. That is the real part of the impedance Z _{TX _ IN} to increase

And a non-uniform dependence on the non-uniform dependence on the non-uniform dependence.

은 전압 정재파 비(voltage standing wave ratio)이고, 반사계수

는 뒤의 수학식 15에 Z_{TX _ IN}에 관한 식으로 정의되어 있다.18 is a diagram showing experimental results of a prototype of the TX unit 110 and the RX unit 120 according to the position of the RX unit 120 according to an embodiment. According to the experimental results, the maximum PTE of the TX coil 112 is 90% and the PTE is 84% regardless of the position and orientation of the RX part 120 in the active fill area. If the mobile device is at a vertical position, the dX position is from -37 mm to +37 mm at positions 1801, 1802 and 1803, and at dots 1804, 1805 and 1806 when the mobile device is horizontal, + 30mm.

Is the voltage standing wave ratio, and the reflection coefficient

It is defined in equation (15) behind the equation for Z _{TX _ IN.}

On the other hand, an analytical solution to the optimal impedance matching circuit in Equations (8), (9), (10) and (11) can provide ideal matching and maximum power transmission efficiency. However, changes in coil parameters at various locations in a mobile device can change impedance matching and efficiency.

In all possible positions of the RX part 120 matching and efficiency levels by the difference between using the reflection coefficient Γ, _{TX _} Z _IN and optimum Z _{TX_IN,} can be predicted. Γ can be calculated from the following equation.

A quantitative evaluation of the allowable level of the TX coil 112 parameter variation can be made using a fine analysis of the circuit input impedance to the coil parameter variation. Reflection coefficient variation is defined as:

Where Z _IND is the impedance induced by the RX coil 121 and can be expressed as:

Consider an optimal match and a small change near the maximum PTE point.

TX coil 112, a real part R1 + change in ReZ _IND of the impedance imaginary part wL ₁ + change in ImZ _IND of, TX coil 112, the impedance, but directly included in the equation (18) is a coefficient Q ₁ / k _² Q ² And is affected by the parameters of the TX coil 112 and the RX coil 121. [

When the RX coil 121 is matched as defined in Equation 8, and the load Z _RECT is a constant, the RX coil 121 parameter changes very small and the resistance change of the TX coil 112 Is negligible.

From any location

In this case, the reflection coefficient change of the equation (18) can be simplified as follows.

As a result, a small coupling factor (k < 0.1) can be made to react very sensitively to the inductance change of the TX coil 112.

19 is a flowchart of a method of designing the TX unit 110 according to an embodiment. Increasing inductive coupling and Q-factor based methods can be applied to improve power transmission efficiency. In the process, the design of the TX coil 112 is a tradeoff between &quot; uniformity of inductive coupling &quot; and inductance variation during the relative change of the position of the RX unit 120 with respect to the TX coil 112 off. Therefore, the design criteria for the TX coil 112 design may be based on the position of the RX portion 120, the input impedance change of the TX coil 112 with the load impedance, and the PTE.

로 나타낼 수 있고, 여기서

는 0.8 내지 0.9의 값을 가질 수 있는 파라미터로서 제 1 보호 소자(130) 및 RX부(120)의 존재로 인한 TX 코일(112) 및 RX 코일(121) 간의 상호 인덕턴스의 감소에 대해 정의한다. Step S110 in FIG. 19 is a step for determining an average inductance coupling coefficient. The average inductive coupling coefficient is the ratio of the surface area S _TX of the TX coil 112 to the surface area S _RX of the RX coil 121

, Where &lt; RTI ID = 0.0 &gt;

Defines a reduction in the mutual inductance between the TX coil 112 and the RX coil 121 due to the presence of the first protective element 130 and the RX portion 120 as parameters that can have a value of 0.8 to 0.9.

Step S120 of FIG. 19 is a step for designing inner turns. The internal turn of the TX coil 112 is designed such that the RX portion 120 is located in the middle portion of the active fill area and the change in inductance L ₁ of the TX coil 112 is minimized when rotating at the middle portion thereof. . The point where the active fill area is not constant in length and width and the asymmetry of the RX coil 121 causes an unavoidable change in the coupling factor. This inevitable change may be minimized by adjusting the dimensions and internal turns.

에 의해서 정의될 수 있다. 최적의 턴 비율

는 0.55일 수 있다.Step S130 of FIG. 19 is a step for setting a turn ratio. Uniformity of the uniform coupling and TX coil 112 input impedance needs to be maintained if the RX portion 120 is located within a certain distance from the center of the active fill area. The outer turns of the TX coil 112 need to be located as close as possible between turns to provide a minimum inductance change out of the possible positions of the RX portion 120. [ In the parametric model of the aforementioned TX coil 112, uniformity is determined by the turn ratio &lt; RTI ID = 0.0 &gt;

. &Lt; / RTI &gt; Optimal turn ratio

Can be 0.55.

Step S140 of FIG. 19 is a step for determining the line width and the number of conductive turns. The line width of the TX coil 112 and the number N of conductive turns can be optimized based on the following. Increasing N allows the RX portion 120 to maintain high coupling uniformity when in various positions, while N is limited because there is a limit on the minimum coil line width. On the other hand, the reduction of the coil line width reduces the average coupling factor and Q ₁ , thus reducing the maximum efficiency. An increase in coil line width improves Q ₁ , but increases the change in TX coil 112 inductance when RX portion 120 is located close to the edge of the active fill region. The line width of the TX coil 112 and the number N of the conductive turns can be optimized in consideration of these factors. The Q-factor does not depend on the line width because the resistance loss reduction of the TX coil 112 due to the increase in line width is relatively small. This phenomenon is related to the flow of current at the lead surface is not uniform and is most at the edge of the lead. The mutual inductance between the TX coil 112 and the RX coil 121 is independent of the line width. As a result, as the resistance of the TX coil 112 decreases, the efficiency increases in accordance with equation (5).

15 mm인 경우는 k=0.129로 감소한다.Step S150 of FIG. 19 is a step for designing an outer turn. The outer turn of the TX coil 112 should be rounded to the maximum possible radius of curvature to increase the average coupling coefficient. For example, as shown in Fig. 2, if the rounded shape is maximized, k = 0.157,

In the case of 15 mm, k decreases to 0.129.

Step S160 in Fig. 19 is a step for designing the impedance matching circuit. The optimum impedance matching circuit can be calculated using Equations (8), (9), (10) and (11). The calculated first and second impedance matching circuits 113 and 122 can provide the optimum matching and the maximum PTE. The effect of the impedance matching and the PTE change due to the change of the position of the RX unit 120 can be seen from the equation (18).

This disclosure can reduce electromagnetic radiation emissions outside the active charging area of the wireless charger, reduce parasitic radiation emissions by the transmission coil, and prevent electronic devices from being interfered with by electromagnetic radiation emissions . Multiple mobile devices can provide maximum power transmission efficiency at any location or in any direction.

This disclosure enables the ultimate goal of a wireless charging system, such as freedom of space and position, and various charging environments. The disclosed resonator design provides ergonomic solutions for wireless power stations in public places such as all wearable devices in homes or offices, restaurants, coffee shops, libraries, and the like.

One embodiment provides high efficiency wireless charging for a plurality of mobile and wearable devices, including smartphones, smart watches, smart glasses, tablet computers and laptops, to provide.

It is to be understood that the foregoing description of the disclosure is for the purpose of illustration only and that those skilled in the art will readily understand that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present disclosure may be indicated by the appended claims rather than by the foregoing description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents may be included within the scope of this disclosure .

Claims (16)

Transmitting coil;
A protective element composed of a conductive material; And
And an impedance matching circuit for connecting the transmission coil and the power source,
Wherein the impedance matching circuit comprises at least two capacitors connected in parallel with the transmit coil to connect the transmit coil to ground and the protection element of the power source. The method according to claim 1,
Wherein at least one tab of the transmission coil is connected to the ground of the protection element and the power source. 3. The method of claim 2,
Wherein the at least one tab is connected to a ground of the protection element and the power source through a galvanic or capacitive connection. The method of claim 3,
Wherein the capacitive connection is formed by lumped capacitor elements or by mutual capacitance between the at least one tab and the protection element. 3. The method of claim 2,
Wherein the at least one tab comprises a center tap of the transmitting coil. 3. The method of claim 2,
Wherein the at least one tab comprises a center tap of the transmitting coil. The method according to claim 6,
Wherein the resonance frequency of the MRI absorption element is equal to a frequency at which the electromagnetic radiation emission by the transmission coil becomes a peak. The method according to claim 1,
Wherein the protection element is generated using at least one of a copper material and a ferrite material. The method according to claim 1,
Wherein the spacing between the conductive turns of the transmitting coil decreases as the distance from the central portion of the transmitting coil to the outer edges decreases. The method according to claim 1,
Wherein the radius of curvature of the transmission coil turn is maximum at the outer periphery and decreases toward the central portion of the transmission coil. 1. A wireless power receiver connectable to a battery,
Receiving coil;
And an impedance matching circuit for connecting the receiving coil and the battery,
Wherein the impedance matching circuit comprises at least two parallel capacitors connected in parallel with the receive coil to couple the receive coil to the ground of the battery. 12. The method of claim 11,
And a protective element comprised of a conductive material disposed adjacent the receive coil. 12. The method of claim 11,
Wherein the protection element is generated using at least one of a copper material and a ferrite material. 12. The method of claim 11,
At least two series capacitors connected in series with the receiving coil to connect the receiving coil and the battery;
At least two inductors connecting between each of said at least two series capacitors and said battery; And
Further comprising at least two capacitors connecting the ground of the battery and the at least two series capacitors and the at least two inductors. 12. The method of claim 11,
And a rectifier coupled to the impedance matching circuit. A transmission coil, a power source, a protection element, and an impedance matching circuit for connecting the transmission coil and the power source,
Wherein the impedance matching circuit comprises at least two capacitors connected in parallel with the transmission coil to couple the transmission coil to the ground of the power source and the protection element. And
A receiving coil, a load, and an impedance matching circuit connecting the receiving coil and the load,
Wherein the impedance matching circuit comprises at least two capacitors connected in parallel with the receiving coil to couple the receiving coil to the ground of the load.

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