US20200018488A1

US20200018488A1 - Determining cookware location on a cooktop appliance based on response to an electromagnetic pulse

Info

Publication number: US20200018488A1
Application number: US16/034,418
Authority: US
Inventors: Michael Blum
Original assignee: Haier US Appliance Solutions Inc
Current assignee: Haier US Appliance Solutions Inc
Priority date: 2018-07-13
Filing date: 2018-07-13
Publication date: 2020-01-16
Also published as: WO2020011136A1

Abstract

A cooktop appliance includes first and second heating elements and a controller operably connected to the first and second heating elements. The controller is configured for receiving a signal from a temperature sensor associated with a cooking utensil. The controller is also configured for generating an electromagnetic pulse with the first heating element for a testing period, and monitoring a voltage or a current associated with the temperature sensor during the testing period. The controller is configured for determining that the cooking utensil is located on the first heating element when the voltage or current associated with the temperature sensor displays electromagnetic interference from the electromagnetic pulse.

Description

FIELD

The present subject matter relates generally to cooktop appliances, or more particularly to methods for operating cooktop appliances.

BACKGROUND

Cooktop appliances generally include heating elements for heating cooking utensils, such as pots, pans and griddles. A user can select a desired heating level, and operation of the heating elements is modified to match the desired heating level. For example, certain cooktop appliances include electric heating elements. During operation, such a cooktop appliance operates the electric heating elements at a predetermined power output corresponding to a selected heating level.
Operating the heating elements at the predetermined power output corresponding to the selected heating level poses certain challenges. For example, the predetermined power output is only an indirect measurement of the actual cooking temperature. Some cooktop appliances employ a temperature sensor to directly measure the temperature of a cooking utensil and/or articles contained within the cooking utensil. The measured temperature may then be used to adjust the power output above or below the predetermined level in order to achieve a cooking temperature closer to the selected heating level.
However, in some instances the cooking utensil with the temperature sensor may be misplaced. For example, the cooking utensil with the temperature sensor may be located on a heating element other than the heating element which is adjusted based on the measured temperature. Further, the cooking utensil with the temperature sensor may be a first cooking utensil and a second cooking utensil may be located on the heating element which is adjusted based on the measured temperature of the first cooking utensil. In such cases, the articles in the first cooking utensil may not be heated as desired and the power output of the heating element which is adjusted based on the measured temperature may be adjusted to a level that is unsuitable for the second cooking utensil and/or articles therein, which can degrade the cooking performance of the cooktop appliance.
Accordingly, a cooktop appliance with features for avoiding such degraded cooking performance would be useful. In particular, a cooktop appliance with features for determining or verifying that a cooking utensil with a temperature sensor corresponds to or is correctly located on the heating element of the cooktop appliance which is controlled based on measurements from the temperature sensor would be particularly beneficial.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.
In an exemplary aspect of the present disclosure, a cooktop appliance is provided. The cooktop appliance includes first heating element and a second heating element. The first and second heating elements are positioned at a cooktop surface of the cooktop appliance. The cooktop appliance also includes a controller operably connected to the first and second heating elements. The controller is configured for receiving a signal from a temperature sensor associated with a cooking utensil located on one of the first heating element and the second heating element. The signal is indicative of a temperature associated with the cooking utensil. The controller is also configured for generating an electromagnetic pulse with the first heating element for a testing period and monitoring a voltage or a current associated with the temperature sensor during the testing period. The controller is further configured for determining that the cooking utensil is located on the first heating element when the voltage or current associated with the temperature sensor displays electromagnetic interference from the electromagnetic pulse.
In another exemplary aspect, a method of operating a cooktop appliance is provided. The cooktop appliance has a first heating element and a second heating element positioned at a cooking surface of the cooktop appliance. The cooktop appliance is in operative communication with a temperature sensor associated with a cooking utensil located on one of the first heating element and the second heating element. The method includes generating an electromagnetic pulse with the first heating element for a testing period and monitoring a voltage or a current associated with the temperature sensor during the testing period. The method further includes determining that the cooking utensil is located on the first heating element when the voltage or current associated with the temperature sensor displays electromagnetic interference from the electromagnetic pulse.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

FIG. 1 provides a perspective view of a range having a cooktop appliance according to one or more exemplary embodiments of the present subject matter.

FIG. 2 provides a schematic view of the cooktop appliance of FIG. 1 with an induction heating element of the cooktop appliance shown heating a cooking utensil on the induction heating element.

FIG. 3 provides a top, schematic view of the exemplary cooktop appliance of FIG. 1.

FIG. 4 provides a schematic diagram of a control system as may be used with the exemplary cooktop appliance of FIG. 2.

FIG. 5 provides an additional top, schematic view of the exemplary cooktop appliance of FIG. 1.

FIG. 6 provides a flow chart of an exemplary method of operating a cooktop appliance.

FIG. 7 illustrates an exemplary current through a temperature sensor according to at least one embodiment in response to an electromagnetic pulse from a heating element when a cooking utensil associated with the temperature sensor is on the heating element.

FIG. 8 illustrates an exemplary current through the temperature sensor of FIG. 7 in response to the electromagnetic pulse from the heating element when the cooking utensil associated with the temperature sensor is not on the heating element.

FIG. 9 illustrates an exemplary voltage across a temperature sensor according to at least one embodiment in response to an electromagnetic pulse from a heating element at a low setting when a cooking utensil associated with the temperature sensor is on the heating element.

FIG. 10 illustrates an exemplary voltage across the temperature sensor of FIG. 9 in response to an electromagnetic pulse from the heating element at a high setting when the cooking utensil associated with the temperature sensor is on the heating element.

FIG. 11 illustrates an exemplary voltage across the temperature sensor of FIG. 9 in response to an electromagnetic pulse from the heating element at a low setting when the cooking utensil associated with the temperature sensor is not on the heating element.

FIG. 12 illustrates an exemplary voltage across the temperature sensor of FIG. 9 in response to an electromagnetic pulse from the heating element at a high setting when the cooking utensil associated with the temperature sensor is not on the heating element.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
As used herein, terms of approximation, such as “generally,” or “about” include values within ten percent greater or less than the stated value. When used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction, e.g., “generally vertical” includes forming an angle of up to ten degrees in any direction, e.g., clockwise or counterclockwise, with the vertical direction V.
FIG. 1 provides a perspective view of a range appliance, or range 10, including a cooktop 12. Range 10 is provided by way of example only and is not intended to limit the present subject matter to the arrangement shown in FIG. 1. Thus, the present subject matter may be used with other range 10 and/or cooktop 12 configurations, e.g., double oven range appliances, standalone cooktop appliances, cooktop appliances without an oven, etc.
A cooking surface 14 of cooktop appliance 12 includes a plurality of heating elements 16. The heating elements 16 are generally positioned at, e.g., on or proximate to, the cooking surface 14. In certain exemplary embodiments, cooktop 12 may be an induction cooktop with induction heating elements mounted below cooking surface 14. For the embodiment depicted, the cooktop 12 includes five heating elements 16 spaced along cooking surface 14. However, in other embodiments, the cooktop appliance 12 may include any other suitable shape, configuration, and/or number of heating elements 16. Each of the heating elements 16 may be the same type of heating element 16, or cooktop appliance 12 may include a combination of different types of heating elements 16. For example, in various embodiments, the cooktop appliance 12 may include any other suitable type of heating element 16 in addition to the induction heating element, such as a resistive heating element or gas burners, etc.
As shown in FIG. 1, a cooking utensil 18, such as a pot, pan, or the like, may be placed on a heating element 16 to heat the cooking utensil 18 and cook or heat food items placed in cooking utensil 18. Range appliance 10 also includes a door 20 that permits access to a cooking chamber (not shown) of range appliance 10, e.g., for cooking or baking of food items therein. A control panel 22 having controls 24 permits a user to make selections for cooking of food items. Although shown on a backsplash or back panel 26 of range appliance 10, control panel 22 may be positioned in any suitable location. Controls 24 may include buttons, knobs, and the like, as well as combinations thereof, and/or controls 24 may be implemented on a remote user interface device such as a smartphone, as described below. As an example, a user may manipulate one or more controls 24 to select a temperature and/or a heat or power output for each heating element 16. The selected temperature or heat output of heating element 16 affects the heat transferred to cooking utensil 18 placed on heating element 16.
As will be discussed in greater detail below, the cooktop appliance 12 includes a control system 50 (FIG. 4) for controlling one or more of the plurality of heating elements 16. Specifically, the control system 50 may include a controller 52 (FIGS. 3 and 4) operably connected to the control panel 22 and controls 24. The controller 52 may be operably connected to each of the plurality of heating elements 16 for controlling a heating level each of the plurality of heating elements 16 in response to one or more user inputs received through the control panel 22 and controls 24.
FIG. 2 provides a schematic view of induction heating element 16 shown heating a cooking utensil 18 supported on cooking surface 14. Induction heating element 16 includes a Lenz coil or wire 15. As will be understood by those skilled in the art, cooktop appliance 10 can supply a current to Lenz coil 15. As such, current passes through Lenz coil 15 and Lenz coil 15 generates a magnetic field (shown with dashed lines M). The magnetic field can be a high frequency circulating magnetic field. As shown in FIG. 2, Lenz coil 15 can be oriented such that magnetic field M is directed towards and through cooking surface 14 to cooking utensil 18. In particular, when magnetic field M penetrates cooking utensil 18, magnetic field M induces a circulating electrical current within cooking utensil 18, e.g., within a bottom wall 19 of cooking utensil 18. The material properties of cooking utensil 18 restrict a flow of the induced electrical current and convert the induced electrical current into heat within cooking utensil 18. As cooking utensil 18 heats up, contents 32 of cooking utensil 18 contained therein heat up as well. In such a manner, induction heating element 16 can cook contents 32 of cooking utensil 18.
Referring now to FIG. 3, a top, schematic view of the cooktop 12 of FIG. 1, or more specifically of the cooking surface 14 of the cooktop 12 of FIG. 1, is provided. As stated, the cooking surface 14 of the cooktop 12 for the embodiment depicted includes five heating elements 16 spaced along the cooking surface 14. A cooking utensil 18, also depicted schematically, is positioned on a first heating element 16 of the plurality of heating elements 16. For the embodiment depicted, a cookware temperature sensor 28 and a food temperature sensor 30 are also associated with the cooking utensil 18.
In some example embodiments, the cookware temperature sensor 28 may be in contact with, attached to, or integrated into the cooking utensil 18 and configured to sense a temperature of, e.g., a bottom surface of the cooking utensil 18 or bottom wall of the cooking utensil 18. For example, the cookware temperature sensor 28 may be embedded within the bottom wall of the cooking utensil 18 as illustrated in FIG. 4. Alternatively, cookware temperature sensor 28 may be embedded within a side wall of the cooking utensil 18, e.g., proximate to the bottom surface or bottom wall of the cooking utensil 18.
Additionally, the food temperature sensor 30 may be positioned at any suitable location to sense a temperature of one or more food items 32 (see FIG. 4) positioned within the cooking utensil 18. For example, the food temperature sensor 30 may be a probe type temperature sensor configured to be inserted into one or more food items 32. Alternatively, however, the food temperature sensor 30 may be configured to determine a temperature of one or more food items positioned within the cooking utensil 18 in any other suitable manner.
In certain exemplary embodiments, one or both of the cookware temperature sensor 28 and the food temperature sensor 30 may utilize any suitable technology for sensing/determining a temperature of the cooking utensil 18 and/or food items 32 positioned in the cooking utensil 18. The cookware temperature sensor 28 and the food temperature sensor 30 may measure a respective temperature by contact and/or non-contact methods. For example, one or both of the cookware temperature sensor 28 and the food temperature sensor 30 may utilize one or more thermocouples, thermistors, optical temperature sensors, infrared temperature sensors, resistance temperature detectors (RTD), etc. The specific structure and function of such sensors are well understood by those of skill in the art, as such, the sensors are not described or shown in further detail for the sake of clarity and concision.
Referring again to FIGS. 3 and 4, the cooktop appliance 12 additionally includes at least one receiver 34. In the illustrated example of FIG. 3, the cooktop appliance 12 includes a plurality of receivers 34, each receiver 34 associated with an individual heating element 16. Each receiver 34 is configured to receive a signal from the food temperature sensor 30 indicative of a temperature of the one or more food items 32 positioned within the cooking utensil 18 and/or from the cookware temperature sensor 28 indicative of a temperature of the cooking utensil 18 positioned on a respective heating element 16. In other embodiments, a single receiver 34 may be provided and the single receiver 34 may be operatively connected to one or more than one of the sensors. In at least some exemplary embodiments, one or both of the cookware temperature sensor 28 and the food temperature sensor 30 may include wireless transmitting capabilities, or alternatively may be hard-wired to the receiver 34, e.g., through a wired communications bus.
FIG. 4 provides a schematic view of a system for operating a cooktop appliance 12 in accordance with an exemplary embodiment of the present disclosure. Specifically, FIG. 4 provides a schematic view of a heating element 16 of the exemplary cooktop appliance 12 of FIGS. 1 through 3 and an exemplary control system 50.
As stated, the cooktop appliance 12 includes a receiver 34 associated with one or more of the heating elements 16, for example a plurality of receivers 34 each associated with a respective heating element 16. For the embodiment depicted, each receiver 34 is positioned directly below a center portion of a respective heating element 16. Moreover, for the embodiment depicted, each receiver 34 is configured as a wireless receiver 34 configured to receive one or more wireless signals. Specifically, for the exemplary control system 50 depicted, both of the cookware temperature sensor 28 and the food temperature sensor 30 are configured as wireless sensors in wireless communication with the wireless receiver 34 via a wireless communications network 54. In certain exemplary embodiments, the wireless communications network 54 may be a wireless sensor network (such as a Bluetooth communication network), a wireless local area network (WLAN), a point-to point communication networks (such as radio frequency identification (RFID) networks, near field communications networks, etc.), a combination of two or more of the above communications networks, or any suitable wireless communications network or networks.
Referring still to FIG. 4, each receiver 34 associated with a respective heating element 16 is operably connected to a controller 52 of the control system 50. The receivers 34 may be operably connected to the controller 52 via a wired communication bus (as shown), or alternatively through a wireless communication network similar to the exemplary wireless communication network 54 discussed above. The controller 52 may generally include a computing device 56 having one or more processor(s) 58 and associated memory device(s) 60. The computing device 56 may be configured to perform a variety of computer-implemented functions to control the exemplary cooktop appliance 12. The computing device 56 can include a general purpose computer or a special purpose computer, or any other suitable computing device. It should be appreciated, that as used herein, the processor 58 may refer to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, and other programmable circuits. Additionally, the memory device(s) 60 may generally comprise memory element(s) including, but not limited to, computer readable medium (e.g., random access memory (RAM)), computer readable non-volatile medium (e.g., a flash memory), a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disc (DVD), and/or other suitable memory elements. The memory 60 can store information accessible by processor(s) 58, including instructions that can be executed by processor(s) 58. For example, the instructions can be software or any set of instructions that when executed by the processor(s) 58, cause the processor(s) 58 to perform operations. For the embodiment depicted, the instructions may include a software package configured to operate the system, e.g., to execute the exemplary methods described below.
Referring still to FIG. 4, the control system 50 additionally includes a user interface 62 operably connected to the controller 52. For the embodiment depicted, e.g., in FIG. 4, the user interface 62 is configured in wired communication with the controller 52. However, in other exemplary embodiments, e.g., as shown in FIG. 3, the user interface 62 may additionally or alternatively be wirelessly connected to the controller 52 via one or more suitable wireless communication networks (such as the exemplary wireless communication network 54 described above). In certain exemplary embodiments, user interface 62 may be configured as the control panel 22 and plurality of controls 24 on the cooktop appliance 12 (see FIG. 1). Additionally, or alternatively, the user interface 62 may be configured as an external computing device or remote user interface device, such as a smart phone, tablet, or other device capable of connecting to the controller 52 of the exemplary control system 50. For example, in some embodiments, the remote user interface may be an application or “app” executed by a remote user interface device such as a smart phone or tablet. Signals generated in controller 52 operate the cooktop 12 in response to user input via the user interface 62.
Further, the controller 52 is operably connected to each of the plurality of heating elements 16 for controlling a power level of each of the plurality of heating elements 16 in response to one or more user inputs through the user interface 62 (e.g., control panel 22 and controls 24). Specifically, for the embodiment depicted, wherein one or more of the heating elements 16 are configured as induction heating elements, the controller 52 is operably connected to a plurality of current control devices 64, each current control device 64 associated with a respective one of the induction heating elements 16.
Turning now to FIG. 5, a first cooking utensil 18A is illustrated, which may include one or both of the cookware temperature sensor 28 and the food temperature sensor 30, e.g., as in any one or combination of the above-described examples. Also shown in FIG. 5 is a second cooking utensil 18B. As shown in FIG. 5, the heating element which is controlled in response to measured temperature from the temperature sensor(s) 28 and/or 30 may be a first heating element 16A, and the cooktop 12 may also include a second heating element 16B. With such exemplary cooktops 12, one or more cooking utensils may be misplaced. For example, as illustrated in FIG. 5, the first and second cooking utensils 18A and 18B are both misplaced. The first cooking utensil 18A is not placed on the first heating element 16A, which is controlled in response to temperature measurements from the temperature sensor(s) 28 and/or 30 located in the first cooking utensil 18A, such that the intended responsive heating is not provided to first cooking utensil 18A and articles therein. As used herein and as is generally understood in the art, a utensil “on” a heating element is positioned in close proximity to the heating element sufficient to be heated by the heating element, e.g., within the magnetic field of an induction heating element, but the utensil is not necessarily in direct physical contact with the heating element to be “on” the heating element. The second cooking utensil 18B is also misplaced in that the second cooking utensil 18B and articles therein may be heated by the first heating element 16A at a level which is responsive to a temperature other than the actual temperature of the second cooking utensil 18B and any food articles 32 therein, e.g., the temperature measured by the sensor(s) 28 and/or 30 in the first cooking utensil 18A.
In some embodiments, the controller 52 may be configured to receive a signal from a temperature sensor associated with first cooking utensil 18A located on one of the first heating element 16A and the second heating element 16B, e.g., via the receiver 34 as described above. The signal may be indicative of a temperature associated with the first cooking utensil 18A. For example, the temperature sensor may be associated with the cooking utensil 18A in that the temperature sensor is positioned and configured to sense a temperature of the cooking utensil 18A itself, such as the cookware temperature sensor 28, and/or a temperature of the contents of the cooking utensil, such as the food temperature sensor 30. In order to confirm that the first cooking utensil 18A is located on the first heating element 16A, the controller 52 may further be configured to determine the location of the first cooking utensil 18A based on electromagnetic interference detected via the temperature sensor(s) 28 and/or 30.
FIG. 6 illustrates an exemplary method 200 of operating a cooktop appliance, such as the exemplary cooktop 12. In some embodiments, the controller 52 may be configured to perform some or all of the steps of method 200. The method 200 may initially include receiving a signal 202, e.g., from the control panel or one or more controls of a plurality of controls. Receipt of such a signal may be indicative of a desire or intent to perform a closed-loop controlled cooking operation based on the measured temperature measured by the temperature sensor(s) 28 and/or 30 associated with a specific item of cookware, e.g., first cooking utensil 18A, on a specific intended burner, e.g., first heating element 16A. Before initiating such a cooking operation, the method 200 may include determining that the measured temperature is associated with a cooking utensil on the intended heating element, e.g., the heating element which is controlled based on the measured temperature, as described below.
For example, in some embodiments, method 200 may include a step 204 of and/or the controller 52 may be configured for generating an electromagnetic pulse for a testing period. In some embodiments, the electromagnetic pulse may be generated by activating the first heating element 16A, e.g., by supplying a current to the coil 15 (FIG. 2) of the first heating element 16A, for a predetermined period of time. In some embodiments, the predetermined period of time may be a first predetermined period of time and generating the electromagnetic pulse may also include deactivating the first heating element 16A, e.g., discontinuing the current flow to the coil 15, for a second predetermined period of time following the first predetermined period of time. Thus, the testing period may include one or more predetermined periods of time.
In various embodiments, the second heating element 16B may be deactivated or activated at a low heating level during the testing period. In such embodiments, the location of the first cooking utensil 18A can be determined or confirmed with a minimal or no interruption in the desired cooking operation because of the instantaneous response of electromagnetic fields from the electromagnetic pulse.
The method 200 may further include a step 206 of monitoring a voltage or a current associated with the temperature sensor during the testing period. For example, voltage or current values associated with the temperature sensor(s) 28 and/or 30 may be continuously measured over the testing period. Thus, it should be understood that “monitored,” “monitoring,” or other cognates thereof as used herein include continuous or repeated measuring or sampling of data, e.g., voltage or current, over a period of time. In at least some embodiments, whether the voltage or the current is monitored may depend on what type of sensor is used. For example, in some embodiments, the temperature sensor 28 and/or 30 may be a thermocouple and the controller 52 may be configured for monitoring a voltage across the thermocouple during the testing period. As another example, in some embodiments, the temperature sensor 28 and/or 30 may be one of a thermistor or a resistance temperature detector, and the controller 52 may be configured for monitoring a current through the temperature sensor during the testing period.
The method 200 may also include, at step 208, determining whether the temperature sensor displays or exhibits electromagnetic interference from the electromagnetic pulse, e.g., whether the monitored voltage or current is greater than a predefined threshold. If so, it may be determined that the cooking utensil is located on the correct intended heating element, e.g., the first heating element 16A. For example, in some embodiments where the voltage across the temperature sensor is monitored, the displayed electromagnetic interference may include a peak-to-peak voltage greater than a predetermined threshold. In such embodiments, the displayed electromagnetic interference may also or instead include a maximum voltage or a minimum voltage greater than a predetermined threshold. As another example, in some embodiments where the current through the temperature sensor is monitored, the displayed electromagnetic interference may include a current greater than a predetermined threshold.
Once it has been determined that the first cooking utensil 18A and the associated temperature sensor(s) 28 and/or 30 are located on the first heating element 16A, the method 200 may include a step 210 of adjusting a heating level of the first heating element 16A based on the received signal from the temperature sensor. For example, the controller 52 may then operate the first heating element 16A in response to the measured temperature, e.g., by adjusting a heating level of the first heating element 16A based on the received signal from the temperature sensor(s) 28 and/or 30. For example, adjusting the heating level may include supplying a variable power level to the first heating element 16A based on the measured temperature, e.g., using a closed control loop such as a PI or PID control. For example, as is generally understood in the art, the measured temperature may be input into a closed control loop and the operation of the first heating element 16A, e.g., the heating level, may be adjusted based on the output of the closed control loop.
In some embodiments, when the electromagnetic interference is not detected, e.g., before the testing period elapses, the method 200 may further include a step 212 of and/or the controller 52 may further be configured for deactivating the first heating element 16A. In such cases, a notification such as an error message or alert, e.g., via user interface 62, may also be provided when the electromagnetic interference is not detected.
As mentioned above, the displayed electromagnetic interference may include a current greater than a predetermined threshold. For example, FIG. 7 illustrates a current response 300 of an exemplary temperature sensor, in this embodiment, a thermocouple, where the current 300 through the temperature sensor exhibits electromagnetic interference in response to the electromagnetic pulse generated by the first heating element 16A. The presence of electromagnetic interference may be determined based on one or both of a maximum positive current (Mp) or a maximum negative current (M_N), or a peak current (Mp+M_N) compared to the predetermined threshold. FIG. 8 illustrates a current response of the thermocouple, which may be an embodiment of the cookware temperature sensor 28 or the food temperature sensor 30, to the electromagnetic pulse generated with the first heating element 16A when the cooking utensil with which the thermocouple is associated, e.g., the first cooking utensil 16A, is not on the first heating element 16A. As may be seen in FIG. 8, a background current 302 is shown through the thermocouple which is greater than zero but is significantly smaller than the current 300 through the thermocouple in FIG. 7.
As mentioned above, the displayed electromagnetic interference may include a peak-to-peak voltage greater than a predetermined threshold and/or a maximum voltage or a minimum voltage greater than a predetermined threshold. For example, FIGS. 9 and 10 illustrate voltage responses of an exemplary temperature sensor such as a thermistor or an RTD. In FIGS. 9 and 10, the voltage across the temperature sensor exhibits electromagnetic interference in response to the electromagnetic pulse generated by the first heating element 16A. The presence of electromagnetic interference may be determined based on any one or more of a peak-to-peak voltage, e.g., an amplitude, a maximum voltage, or a minimum voltage, compared to the predetermined threshold. For example, FIG. 9 illustrates an exemplary voltage 400 across the temperature sensor in response to an electromagnetic pulse from the first heating element 16A at a low setting, which includes an amplitude A_L, a maximum voltage M_L, and a minimum voltage N_L, when the first cooking utensil 18A is on the first heating element 16A. As another example, FIG. 10 illustrates an exemplary voltage 402 across the temperature sensor in response to an electromagnetic pulse from the first heating element 16A at a high setting, which includes an amplitude A_H, a maximum voltage M_H, and a minimum voltage N_H, when the first cooking utensil 18A is on the first heating element 16A.
FIGS. 11 and 12 illustrate voltage responses of the temperature sensor to the electromagnetic pulse generated with the first heating element 16A when the first cooking utensil 16A is not on the first heating element 16A. In the example illustrated by FIGS. 11 and 12, some measurable response may be seen, such as when the first cooking utensil 18A is near but not on the first heating element 16A, e.g., the first cooking utensil 18A may be on a heating element immediately adjacent to the first heating element 16A. For example in FIG. 11, some changes in the voltage 404 in response to the electromagnetic pulse generated by the first heating element at a low setting can be seen. As another example, some changes in the voltage 406 in response to the electromagnetic pulse generated by the first heating element at a high setting can be seen in FIG. 12. Although some measurable voltage response is shown in FIGS. 11 and 12, the corresponding values of A_L, M_L, N_L, A_H, M_H, and N_Hare significantly smaller in FIGS. 11 and 12 than in FIGS. 9 and 10, which indicates that the first cooking utensil 18A is not on the first heating element 16A.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

What is claimed is:

1. A cooktop appliance, comprising:

a first heating element and a second heating element, the first and second heating elements positioned at a cooktop surface of the cooktop appliance; and

a controller operably connected to the first and second heating elements, the controller configured for:

receiving a signal from a temperature sensor associated with a cooking utensil located on one of the first heating element and the second heating element, the signal indicative of a temperature associated with the cooking utensil;

generating an electromagnetic pulse with the first heating element for a testing period;

monitoring a voltage or a current associated with the temperature sensor during the testing period; and

determining that the cooking utensil is located on the first heating element when the voltage or current associated with the temperature sensor displays electromagnetic interference from the electromagnetic pulse.

2. The cooktop appliance of claim 1, wherein the temperature sensor comprises a thermocouple and the controller is configured for monitoring a voltage across the thermocouple during the testing period.

3. The cooktop appliance of claim 1, wherein the temperature sensor comprises one of a thermistor or a resistance temperature detector and the controller is configured for monitoring a voltage across or a current through the temperature sensor during the testing period.

4. The cooktop appliance of claim 1, wherein the electromagnetic interference comprises a peak-to-peak voltage greater than a predetermined threshold.

5. The cooktop appliance of claim 1, wherein the electromagnetic interference comprises a current greater than a predetermined threshold.

6. The cooktop appliance of claim 1, wherein the electromagnetic interference comprises one of a maximum voltage and a minimum voltage greater than a predetermined threshold.

7. The cooktop appliance of claim 1, wherein the controller is further configured for deactivating the first heating element and providing a notification when the voltage or current of the conductor does not display electromagnetic interference from the electromagnetic pulse.

8. The cooktop appliance of claim 1, wherein generating the electromagnetic pulse comprises activating the first heating element for a predetermined period of time.

9. The cooktop appliance of claim 1, wherein generating the electromagnetic pulse comprises activating the first heating element for a first predetermined period of time and deactivating the first heating element for a second predetermined period of time following the first predetermined period of time.

10. The cooktop appliance of claim 1, wherein the controller is further configured for adjusting a heating level of the first heating element based on the received signal from the temperature sensor after determining that the cooking utensil is located on the first heating element.

11. A method of operating a cooktop appliance having a first heating element and a second heating element positioned at a cooking surface of the cooktop appliance, the cooktop appliance in operative communication with a temperature sensor associated with a cooking utensil located on one of the first heating element and the second heating element, the method comprising:

12. The method of claim 11, wherein the temperature sensor comprises a thermocouple and the step of monitoring comprises monitoring a voltage across the thermocouple during the testing period.

13. The method of claim 11, wherein the temperature sensor comprises one of a thermistor or a resistance temperature detector and the step of monitoring comprises monitoring a current through the temperature sensor during the testing period.

14. The method of claim 11, wherein the electromagnetic interference comprises a peak-to-peak voltage greater than a predetermined threshold.

15. The method of claim 11, wherein the electromagnetic interference comprises a current greater than a predetermined threshold.

16. The method of claim 11, wherein the electromagnetic interference comprises one of a maximum voltage and a minimum voltage greater than a predetermined threshold.

17. The method of claim 11, further comprising deactivating the first heating element and providing a notification when the voltage or current of the conductor does not display electromagnetic interference from the electromagnetic pulse.

18. The method of claim 11, wherein generating the electromagnetic pulse comprises activating the first heating element for a predetermined period of time.

19. The method of claim 11, wherein generating the electromagnetic pulse comprises activating the first heating element for a first predetermined period of time and deactivating the first heating element for a second predetermined period of time following the first predetermined period of time.

20. The method of claim 11, further comprising adjusting a heating level of the first heating element based on a received signal from the temperature sensor, the signal indicative of a temperature associated with the cooking utensil, after determining that the cooking utensil is located on the first heating element.