Wireless power heating

Abstract

: A wirelessly powered heating apparatus comprises a thermally conductive support element (207) supporting an item to be heated. At least one power extraction heating element (209) is fixed relative to the support element (207). The power extraction heating element (209) is electrically conductive and thermally coupled to the support element (207). It is further arranged to have dimensions that allow it to be heated by eddy currents in the presence of a varying electromagnetic field. The apparatus further comprises a power extracting circuit (211) electrically coupled to opposing ends of the power extraction heating element (209) and extracts electrical power from the power extraction heating element (209). The power extraction heating element (209) (e.g. together with the coupling to the power extracting circuit) form at least one loop enclosing an area which can receive a magnetic flux from a power transmitter.

Description

[0001] 2024PF00482

[0002] WIRELESS POWER HEATING

[0003] FIELD OF THE INVENTION

[0004] The invention relates to wireless power heating and in particular, but not exclusively, to a high power wireless power heating apparatus, such as e.g. a wirelessly powered pan or pot.

[0005] BACKGROUND OF THE INVENTION

[0006] Most present-day electrical products require a dedicated electrical contact in order to be powered from an external power supply. However, this tends to be impractical and requires the user to physically insert connectors or otherwise establish a physical electrical contact. Typically, power requirements also differ significantly, and currently most devices are provided with their own dedicated power supply resulting in a typical user having a large number of different power supplies with each power supply being dedicated to a specific device. Although, the use of internal batteries may avoid the need for a wired connection to a power supply during use, this only provides a partial solution as the batteries will need recharging (or replacing). The use of batteries may also add substantially to the weight and potentially cost and size of the devices. Batteries also tend to be unsuitable for high power applications.

[0007] In order to provide a significantly improved user experience, it has been proposed to use a wireless power supply wherein power is inductively transferred from a transmitter inductor in a power transmitter device to a receiver coil in the individual devices.

[0008] Power transmission via magnetic induction is a well-known concept, mostly applied in transformers having a tight coupling between a primary transmitter inductor / coil and a secondary receiver coil. By separating the primary transmitter coil and the secondary receiver coil between two devices, wireless power transfer between these becomes possible based on the principle of a loosely coupled transformer.

[0009] Such an arrangement allows a wireless power transfer to the device without requiring any wires or physical electrical connections to be made. Indeed, it may simply allow a device to be placed adjacent to, or on top of, the transmitter coil in order to be recharged or powered externally. For example, power transmitter devices may be arranged with a horizontal surface on which a device can simply be placed in order to be powered.

[0010] Furthermore, such wireless power transfer arrangements may advantageously be designed such that the power transmitter device can be used with a range of power receiver devices. In particular, a wireless power transfer approach, known as the Qi Specifications, has been defined and is currently being further developed. This approach allows power transmitter devices that meet the Qi Specifications to be 2024PF00482

[0011] 2

[0012] used with power receiver devices that also meet the Qi Specifications without these having to be from the same manufacturer or having to be dedicated to each other. The Qi standard further includes some functionality for allowing the operation to be adapted to the specific power receiver device (e.g. dependent on the specific power drain).

[0013] The Qi Specification is developed by the Wireless Power Consortium and more information can e.g. be found on their website: http: / / www.wirelesspowerconsortium.com / index.html, where in particular the defined Specification documents can be found.

[0014] The Wireless Power Consortium has on the basis of the Qi Specification proceeded to develop the Ki Specification (also known as the Cordless Kitchen Specification) which is aimed at providing safe, reliable, and efficient wireless power transfer to kitchen appliances. Ki supports much higher power levels up to 2.2KW.

[0015] A particular attractive application for wireless power transfer is heating applications where the electromagnetic field is used to heat items. Indeed, this is seen as one of the key user scenarios and applications for the Ki wireless systems, which are specifically developed to support appliances such as kettles, pots, or pans that may directly heat e.g. food or liquids. Appliances supporting such operation are often generated to include a large metallic heating element that is directly heated by induction from the generated varying electromagnetic field.

[0016] As a specific example, a cooking appliance suitable to be operated wirelessly on an induction cooktop may provide a desirable application and user function. Induction cooktops are becoming increasingly popular, and it is continuously desired to provide an improved function and / or user experience. This has led to a particular desire to include further control functionality that e.g. provides a user interface or controls the temperature etc. However, such functionality requires electrical power which is typically provided by a battery or by the additional inclusion of a power extraction coil to extract electrical power from the electromagnetic field. However, this is typically disadvantageous as it results in additional complexity and cost. Typically, the different requirements are in conflict, and results in more difficult manufacturing. For example, providing coils in a heating appliance is typically difficult and / or expensive and tends to be in conflict with the requirements for optimal and efficient heating.

[0017] Hence, an improved wireless power transfer heating approach would be advantageous and, in particular, an approach allowing increased flexibility, reduced cost, reduced complexity, improved operation, more efficient heating, facilitated manufacturing and / or production, improved support for electrical circuits, improved support for powering electrical circuits, and / or improved performance would be advantageous.

[0018] SUMMARY OF THE INVENTION

[0019] Accordingly, the Invention seeks to preferably mitigate, alleviate or eliminate one or more of the above mentioned disadvantages singly or in any combination. 2024PF00482

[0020] 3

[0021] According to an aspect of the invention there is provided a heating apparatus comprising: a thermally conductive support element for supporting an item to be heated; at least a first power extraction heating element fixed relative to the support element, the first power extraction heating element being thermally coupled to the support element and being arranged to be heated by eddy currents in the presence of a varying electromagnetic field; a power extracting circuit electrically coupled to the first power extraction heating element and arranged to extract electrical power from the first power extraction heating element; and wherein the first power extraction heating element is arranged to form at least one loop enclosing an area.

[0022] The invention may provide an improved heating apparatus for many applications and scenarios. It may typically allow facilitated implementation and / or operation of a heating apparatus. The approach may allow efficient power extraction without requiring additional or dedicated power extraction coils. The approach may allow both efficient electrical power extraction and efficient heating of an item from a magnetic field / signal generated by a power transmitter. The approach may in many scenarios allow such improved functionality while providing for low cost and easy manufacturing and production. The approach may in particular in many embodiments allow a heating apparatus / arrangement with both efficient heating and efficient electrical power extraction while allowing low cost and efficient manufacturing. It may further allow a heating apparatus to be provided with advantageous properties, such as a low profile / cross section of the heating arrangement.

[0023] The first power extraction heating element may be electrically conducting (or at least semi-conducting) and formed by a material with an electrical conductivity of at least 105, 106, or 107S / m.

[0024] A thermally conductive element may have a thermal conductivity of no less than 1, 2, 5, 10, or in some cases even 100 W / mK.

[0025] The power extracting circuit may in many embodiments be electrically coupled to opposite ends of the first power extraction heating element. The first power extraction heating element may typically have a substantially planar extension / shape.

[0026] The first power extraction heating element may form at least one or more open loops being closed by the coupling to the power extracting circuit. The first power extraction heating element may form at least one or more loops being enclosing an area through which a magnetic flux may flow to cause a current / emf being to be induced in the first power extraction heating element.

[0027] A thermally conductive element / material may also be referred to as a heat conductive element / material.

[0028] The power extractor may be arranged to supply an electrical circuit with electrical power extracted from the first power extraction heating element (which is also heated by eddy currents).

[0029] The heating / power loss caused by the eddy currents may be at least 5, 10, 100, 1000 times higher than heating / power loss caused by current through the power extracting circuit / extracted from the heating element by the power extracting circuit. In many cases, at least 80%, 90%, 95% or 99% of the 2024PF00482

[0030] 4

[0031] heating of the heating element may be caused by eddy currents. Eddy currents may be contained within the heating element and no part of an eddy current flows through the power extracting circuit.

[0032] In accordance with some embodiments of the invention, extension in at least two cross-sectional dimensions / directions of the first power extraction heating element exceed 5 mm, or in some embodiments 10mm, 15mm, or 25mm.

[0033] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios. The two cross-sectional dimensions / directions may be orthogonal dimensions / directions .

[0034] In accordance with an optional feature of the invention, extension in a third cross-sectional dimension / direction of the first power extraction heating element does not exceed 5 mm, or in some cases 1, 3, 10 mm.

[0035] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios. The third cross-sectional dimension / direction may be orthogonal to the previously mentioned two dimensions / directions.

[0036] In accordance with an optional feature of the invention, the first power extraction heating element is substantially annular.

[0037] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios.

[0038] In accordance with an optional feature of the invention, the heating apparatus further comprises a second power extraction heating element fixed relative to the support element, the second power extraction heating element being (electrically conductive and) thermally coupled to the support element and being arranged to be heated by eddy currents in the presence of a varying electromagnetic field; wherein the power extracting circuit is electrically coupled to the second power extraction heating element and arranged to extract electrical power from the second power extraction heating element; and the second power extraction heating element is arranged to (together with the coupling to the power extracting circuit) form at least one loop enclosing an area (for receiving a magnetic flux from a power transmitter).

[0039] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios.

[0040] In some embodiments, there may be further power extraction heating elements with corresponding properties. In many embodiments there may be a maximum of 1, 2, 4, 6, or 10 power extraction heating elements.

[0041] In many embodiments, the first power extraction heating element and the second power extraction heating element (and / or any further power extraction heating elements) may be formed from a single sheet metal.

[0042] In accordance with an optional feature of the invention, the first power extraction heating element and the second power extraction heating element are arranged concentrically. 2024PF00482

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[0044] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios.

[0045] In accordance with an optional feature of the invention, the heating apparatus further comprises a heating element having an extension in at least two cross-sectional dimensions / directions exceeding 50 mm, the heating element not having any electrical connections.

[0046] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios. The heating apparatus may in addition to one or more power extraction heating elements comprise one or more non-(electrical) power extraction heat elements.

[0047] The two cross-sectional dimensions / directions may be orthogonal dimensions / directions. In many embodiments, the first power extraction heating element and the heating element may be formed from a single sheet metal.

[0048] The heating element may also be referred to e.g. as the non-electrical power extraction heating element.

[0049] In accordance with an optional feature of the invention, the first power extraction heating element and the heating element are provided in single layer having an extension not exceeding 5 mm, or in some cases 1, 3, or 10 mm.

[0050] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios.

[0051] In accordance with an optional feature of the invention, the heating apparatus further comprises a thermally conductive element having the thermally conductive support element and the first power extraction heating element fixed on opposing sides; wherein an electric conductivity of the support element exceeds that of the thermally conductive element by a factor of no less than ten.

[0052] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios.

[0053] In some embodiments, the thermally conductive support element is metallic, and the heating apparatus further comprises an electrically non-conducting and thermally conductive element having the thermally conductive support element and the first power extraction heating element fixed on opposing sides.

[0054] In accordance with an optional feature of the invention, the first power extraction heating element is composed of a ferrous metal.

[0055] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios.

[0056] In accordance with an optional feature of the invention, the first power extraction heating element is arranged in a spiral shape forming at least two loops.

[0057] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios. 2024PF00482

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[0059] In accordance with an optional feature of the invention, the heating apparatus further comprises a communication coil arranged concentrically with the first power extraction heating element; and a communication circuit coupled to the communication coil and arranged to communicate using the communication coil.

[0060] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios.

[0061] The communication may typically be with a power transmitter generating the varying electromagnetic field.

[0062] In accordance with an optional feature of the invention, there is provided a wireless power heating system comprising: a heating apparatus as previously described; and a wireless power transmitter comprising a power transmitter coil arranged to generate the varying electromagnetic field.

[0063] This may allow particular advantageous operation and / or implementation of a wireless power heating system in many scenarios.

[0064] In accordance with an optional feature of the invention, the wireless power transmitter is a Ki power transmitter.

[0065] This may allow particular advantageous operation and / or implementation of the heating apparatus in many scenarios.

[0066] According to another aspect of the invention there is provided a method of heating an item, the method comprising: providing a thermally conductive support element supporting an item to be heated; providing at least a power extraction heating element fixed relative to the support element, the power extraction heating element being thermally coupled to the support element and being arranged to be heated by eddy currents in the presence of a varying electromagnetic field; a power extracting circuit electrically coupled to the power extraction heating element and extracting electrical power from the power extraction heating element; and wherein the power extraction heating element forms at least one loop enclosing an area.

[0067] These and other aspects, features and advantages of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

[0068] BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which

[0070] Fig. 1 illustrates an example of elements of a power transmitter for wireless power transmission to a heating apparatus;

[0071] Fig. 2 illustrates an example of a heating apparatus in accordance with some embodiments of the invention;

[0072] Fig. 3 illustrates an example of a heating arrangement for a heating apparatus in accordance with some embodiments of the invention; 2024PF00482

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[0074] Fig. 4 illustrates an example of a heating arrangement for a heating apparatus in accordance with some embodiments of the invention;

[0075] Fig. 5 illustrates an example of a heating arrangement for a heating apparatus in accordance with some embodiments of the invention;

[0076] Fig. 6 illustrates an example of a heating arrangement for a heating apparatus in accordance with some embodiments of the invention;

[0077] Fig. 7 illustrates an example of a heating arrangement for a heating apparatus in accordance with some embodiments of the invention;

[0078] Fig. 8 illustrates an example of a heating arrangement for a heating apparatus in accordance with some embodiments of the invention;

[0079] Fig. 9 illustrates an example of a heating arrangement for a heating apparatus in accordance with some embodiments of the invention; and

[0080] Fig. 10 illustrates an example of a heating arrangement for a heating apparatus in accordance with some embodiments of the invention.

[0081] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0082] The following description focuses on embodiments of the invention applicable to a wireless power transfer system arranged to provide heating based wireless power transfer in accordance with the Ki Specification. However, it will be appreciated that the invention is not limited to this application but may be applied to many other wireless power transfer systems.

[0083] The system includes a power transmitter which is arranged to generate a strong electromagnetic field which may induce current in metallic heating elements of a heating apparatus, such as a pot, kettle, or pan.

[0084] The power transmitter specifically generates an inductive electromagnetic power transfer signal / field which may inductively transfer power from the power transmitter to a heating element of a power transmitter. The power transmitter may typically also be able to support other applications such as e.g. providing power to other types of power receivers which do not include any heating element, but which e.g. include power receiving coils for extracting power from the power transfer signal.

[0085] The power transmitter may transfer substantial power levels, and specifically the power transmitter may support power levels in excess of 5W, 50W, 100W or 500W, IkW or even 2kW. Thus, very high power levels may typically be provided for applications, such as e.g. for Ki heating applications.

[0086] FIG. 1 illustrates exemplary elements of a power transmitter. The power transmitter of FIG. 1 includes a driver 101 which can generate a drive signal that is fed to the transmitter coil 103 which in return generates the electromagnetic power transfer signal thereby providing a power transfer to the power receiver. The transmitter coil 103 may be part of an output resonance circuit comprising the transmitter coil 103 and a capacitor. 2024PF00482

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[0088] The driver 101 generates the current and voltage which is fed to the output resonance circuit and thus to the transmitter coil 103. The driver 101 typically comprises a drive circuit in the form of an inverter which generates an alternating signal from a DC Voltage.

[0089] The power transfer signal may typically have a frequency between around 20 kHz to around 1 MHz, and often for Qi compatible systems typically in the range from 95 kHz to 400 kHz or for Ki compatible systems typically in the range between 20kHz to 80kHz. In a traditional system, the transmitter coil and a power receiving coil of a power receiver are loosely coupled and thus the power receiving coil picks up (at least part of) the power transfer signal from the power transmitter. Thus, the power is transferred from the power transmitter to the power receiver via a wireless inductive coupling from the transmitter coil to the power receiving coil. The term power transfer signal is mainly used to refer to the inductive signal / magnetic field generated by the power transmitter / the transmitter coil, but it will be appreciated that by equivalence it may also be considered and used as a reference to an electrical signal provided to the transmitter coil 103.

[0090] The power transmitter comprises a power transmitter controller 105 which is arranged to control the operation of the power transmitter in accordance with the desired operating principles.

[0091] Specifically, the power transmitter may include many of the functionalities required to perform power control in accordance with the Qi or Ki Specifications.

[0092] The power transmitter controller 105 is in particular arranged to control the generation of the drive signal by the driver 101, and it can specifically control the power level of the drive signal, and accordingly the level of the generated power transfer signal. The power transmitter controller 105 may for example comprise a power loop controller controlling a power level of the power transfer signal in response to power control messages received from the power receiver.

[0093] In the example of the power transmitter of FIG. 1, the power transmitter comprises a first communicator 107 which is arranged to receive data and messages from the power receiver as well as transmit data and messages to the power receiver (as will be appreciated by the skilled person, a data message may provide one or more bits of information).

[0094] In the approach, the communication is performed by modulation of a communication carrier that is generated by a first communication coil 109. The first communicator 107 is coupled to the first communication coil 109 and is arranged to generate a communication drive signal which is fed to the first communication coil 109 to generate the communication carrier. The first communicator 107 may typically be arranged to generate the communication drive signal / communication carrier to have a substantially different frequency than the power transfer drive signal / power transfer signal. In many embodiments, the frequency of the communication carrier may be no less than 10, 100, or 500 times higher than the frequency of the power transfer signal. In many embodiments, the frequency of the communication drive signal / communication carrier may have a frequency of no less than 500kHz, 1 MHz, or 10 MHz. Specifically for an NFC implementation, the communication carrier frequency may be 13.56 MHz. 2024PF00482

[0095] 9

[0096] The first communicator 107 may be arranged to modulate the communication drive signal / communication carrier in order to transmit data to the power receiver (in the following references to the communication drive signal also include the implicit reference to the communication carrier as appropriate).

[0097] The modulation is in the specific example an amplitude modulation of the communication drive signal, and specifically a binary communication using Amplitude Shift Keying (ASK) is used. However, it will be appreciated that in other embodiments, the modulation may use other approaches, such as phase or frequency modulation of the communication drive signal.

[0098] For communication from the power receiver to the power transmitter, the modulation of the communication drive signal may be a load modulation. The power receiver may be arranged to modulate the communication drive signal by varying a loading of the communication drive signal generated by the communication coil 109 in accordance with the data to be transmitted. The first communicator 107 is specifically arranged to sense variations in the voltage and / or current of the communication coil 107 and to demodulate the load modulation based on these. In typical embodiments, the first communicator 107 may for example receive data from the power receiver and forward it to the power transmitter controller 105 for controlling the power transfer signal etc.

[0099] In some embodiments, the communication may be in accordance with the Near Field Communication, NFC, Specifications and the power receiver may specifically include NFC functionality. In these embodiments, the first communicator 107 and the first communication coil 109 may implement (at least) the functionality of an NFC reader. Thus, in some embodiments, the communication drive signal / communication carrier is a constant level (except for modulation) 13.56 MHz signal.

[0100] The following description will focus on examples where the communication between the power transmitter and power receiver is by NFC communication and specifically where modulation of the NFC carrier in the direction from the power transmitter to the power receiver is by Amplitude Shift Keying (ASK) and modulation of the NFC carrier in the direction from the power receiver to the power transmitter is by load modulation.

[0101] FIG. 2 illustrates an example of elements of a power receiver which specifically is a heating apparatus arranged to heat an item, such as liquid, food, etc. The apparatus further comprises functionality for interacting with the power transmitter to perform efficient power transfer.

[0102] Specifically, the power receiver comprises a power receiver controller 201 which implements various power receiver controller functionality required to perform power transfer, and in particular functions required to perform power transfer in accordance with the Ki Specifications.

[0103] The power receiver controller 201 may further comprise functionality for controlling / processing communication with the power transmitter. In the example, a separate communication function, such as an NFC communication function, may be employed and the power receiver specifically comprises a second communicator 203 and a second communication coil 205. The 2024PF00482

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[0105] second communication coil 205 is arranged to couple to the first communication coil 109 and thus the communication carrier induces a current (at least an emf) in the second communication coil 205.

[0106] The second communicator 203 is coupled to the second communication coil 205 and is arranged to determine amplitude variations in the induced signal and to demodulate amplitude modulations of the communication carrier. Thus, the second communicator 203 is arranged to decode data transmitted from the power transmitter by amplitude modulation of the communication carrier. It will be appreciated that in other embodiments, the second communicator 203 may be arranged to decode data modulated onto the communication carrier using other modulation formats such as frequency or phase modulation.

[0107] The second communicator 203 is further arranged to load modulate the communication carrier in order to transmit data from the power receiver to the power transmitter. Specifically, the second communicator 203 may comprise a load (such as a capacitor) which depending on the data to transmit can be switched between being coupled to the second communication coil 205 and not being coupled to the second communication coil 205. These load modulations may then be detected by the first communicator 107 of the power transmitter.

[0108] In the specific example, the second communication coil 205 and the second communicator 203 may provide NFC compatible communication operation. Specifically, the second communication coil 205 may be arranged to provide functionality corresponding to an NFC tag and to decode data that has been ASK modulated onto the communication carrier in accordance with the NFC specifications.

[0109] Thus, the second communicator 203 is arranged to transmit data to the power transmitter by varying the loading of the second communication coil 203 in response to data to be transmitted to the power transmitter 101. The load variations are then detected and demodulated by the power transmitter 101 as will be known to the person skilled in the art.

[0110] In the example, the second communicator 203 is furthermore arranged to demodulate amplitude, frequency, and / or phase modulation of the communication carrier in order to retrieve data transmitted from the power transmitter.

[0111] In operation, the system is arranged to control the drive signal such that the power transfer signal attains suitable operating parameters / properties and such that the power transfer operates at a suitable operating point, and in the specific example of a heating apparatus the control may such that a desired measured temperature is achieved by the power transfer. In order to do so, the power transmitter is arranged to control a parameter of the drive signal using a power control loop where a power property of the power transfer signal / drive signal is controlled in response to power control messages that are received from the power receiver. A power control loop is accordingly employed which controls a power property of the power transfer signal to result in the desired operating point at the power receiver. It will be appreciated that many other types of data may be exchanged between the power transmitter and the power receiver to support a range of functions. 2024PF00482

[0112] 11

[0113] The power receiver and the power transmitter can accordingly communicate using a communication carrier which in many cases may be a dedicated communication carrier, such as specifically an NFC communication carrier. In some embodiments, such as specifically Qi applications, the communication may use the power transfer signal as a communication carrier.

[0114] The power transmitter and the power receiver, and typically specifically the power transmitter controller 105 and the power receiver controller 201, may exchange messages and perform the required and desired operations to initiate, establish, perform, and terminate power transfers, and in particularly in many embodiments in accordance with the Ki Specifications.

[0115] The apparatus of FIG. 2 is a heating device, such as specifically kitchen appliance, e.g. a pot, pan, kettle, etc. The following description will focus on an apparatus / device that is arranged to heat items positioned on a suitable support element 207 which is heat / thermally conductive and which provides thermal energy to the items. The support element 207 may specifically be the bottom of the device (e.g. the bottom of a pan, pot, kettle etc) which receives the item (e.g. body of water or other liquid) to be heated. Thus, the support element 207 may specifically provide a surface for receiving the item to be heated.

[0116] The following description will focus on the example of the heating device being a wirelessly powered pan and the support element forming the bottom of the pan.

[0117] In order to provide heating based on the wireless power / electromagnetic field, the power receiver comprises a heating element 209 in which current is induced by the electromagnetic field and resulting in power being dissipated in the element resulting in a temperature increase. The heating element is made from an electrically conductive element and is constructed with dimensions that allow strong eddy currents to be induced allowing efficient heating. The heating element 209 may typically advantageously be formed by (ferrous) metal.

[0118] The heating element 209 is fixed relative to the support element 207 and is thermally coupled to this. Heat energy accordingly flows from the heating element 209 to the support element 207 (when the temperature of the heating element 209 exceeds that of the support element 207) resulting in the support element 207 heating up thereby allowing the item to be heated.

[0119] In the example, the heating element 209 is directly fixed / attached to the support element 207 and thus the two elements are in direct contact. For example, the support element 207 may be a ceramic bowl shaped element with a flat bottom and with the heating element 209 attached (e.g. glue or bonded) to the ceramic support element 207. The heating resulting from the induced eddy currents in the heating element 209 will directly heat the support element 207, and thus any item being positioned in the bowl shaped element.

[0120] The system may typically control the power transfer operation by establishing a power control loop to achieve the desired heating effect. For example, in many embodiments, the power receiver may include a temperature sensor arranged to measure the temperature of the contact surface / the heating element. The measured temperature may be compared to the desired temperature and the power receiver 2024PF00482

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[0122] may transmit power control messages to the power transmitter indicative of a desired power level (change), such as e.g. requesting an increase or decrease in power level. The power transmitter controller 105 may change the power level of the drive signal and thus the generated electromagnetic field accordingly leading to a power control loop that adapts the generated electromagnetic field / the power transfer level to achieve a desired temperature.

[0123] The heating element 209 is accordingly designed such that eddy currents are induced in the heating element 209 such that this is heated effectively by the field generated by the power transmitter. In many cases, at least 50%, 80%, 90%, 95%, or 99% of the power extracted from the electromagnetic field is converted to heat (heating energy / power). The heating element 209 may further be designed such that it allows for efficient flow of thermal energy from the heating element 209 to the item to be heated (typically via the support element 207).

[0124] However, the heating element 209 is further arranged to provide a second function, namely to also provide electrical power extracted from the power transfer signal / the electromagnetic field. Accordingly, the power transmitter comprises a power extracting circuit 211 which is electrically coupled to the heating element 209 and which is arranged to extract electrical energy from the heating element 209. The heating element 209 is arranged to (together with the coupling to the power extracting circuit 211) form at least one loop enclosing an area.

[0125] FIG. 2 illustrates a view of an exemplary planar support structure with an annular / circular heating element 209 (e.g. a view corresponding to viewing the bottom of a pan implementing the specific arrangement). FIG. 3 illustrates a cross sectional side view of the same apparatus device along axis AA of FIG. 2.

[0126] The heating element 209 accordingly forms an electrical loop through which a varying magnetic flux of the electromagnetic field generated by the power transmitter flows thereby resulting in an overall EMF being generated. The heating element 209 may accordingly effectively form a winding of a coil / inductor in which an electrical current is induced by the electromagnetic field.

[0127] The power extracting circuit 211 is coupled to the opposite ends of the loop / winding formed by the heating element 209 and specifically wires / electrodes 213 may be connected to the end parts of the heating element 209. The heating element 209 may accordingly form one or more loops / windings with a gap and with the power extracting circuit 211 being coupled / connected to across the gap.

[0128] In operation, the changing electromagnetic field will induce an emf in the loop resulting in a voltage potential difference between the ends of the loop (between the opposite sides of the gap). The power extracting circuit 211 is coupled to the loop such that it allows a current to flow through the power extracting circuit 211 due to the induced voltage / emf across the power extracting circuit 211. The heating element 209 may thus form a(n open) loop with a gap over which the power extracting circuit 211 is coupled. The gap may typically have a width (minimum distance between the ends of the heating element 209) which does not exceed 5mm, 10 mm, 25mm or 50mm. 2024PF00482

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[0130] The power extracting circuit 211 may further process the extracted electrical signal to generate an electrical supply signal which is suitable for the desired purpose / circuit being powered by the power extracting circuit 211. For example, the power extracting circuit 211 may proceed to perform rectification, smoothing, (voltage or current) regulation etc. as well known to the skilled person. The power extracting circuit 211 may provide an electrical power supply to other functions of the power receiver, or indeed potentially even to electrical circuitry of other devices. For example, the power extracting circuit 211 may provide electrical power to the power receiver controller 201 and to the second communicator 203, and may thus support the core operation required to establish and maintain a power transfer session. In addition, the power extracting circuit 211 may often be used to power other circuits features such user interface functionality, a measurement circuit (e.g. to measure temperature based on suitable temperature sensor 217).

[0131] In the described approach the heating element 209 accordingly performs multiple functions and is a power extraction heating element that provides and extracts both thermal and electrical energy from the electromagnetic field. In many embodiments, the approach may provide a single metal layer for application to or semi-integration with e.g. a cooking pan to be used on an induction cooktop in which both heat as well as electrical power can be generated in a practical and easy way.

[0132] The heating element 209 is accordingly designed to be suitable for both extraction of electrical and thermal energy for respectively powering electrical circuits and for providing the desired heating. In order to provide desirable heating performance, the heating element 209 is generated to have a substantial extension in at least two (orthogonal) dimensions / directions. In most cases, the heating element 209 may be formed as a relatively flat element but with substantial extension in the two dimensions of the plane of the element.

[0133] In many embodiments, the power extracted by the power extracting circuit 211 is relatively low in comparison to the heating power generated by the eddy currents, indeed in many embodiments it may be no less than 5, 10, 100, or 1000 times higher. In many embodiments, any power extracted from the heating element 209 by current flowing out of / into the heating element is at least 5, 10, 100, or 1000 times lower than the heating power caused by eddy currents.

[0134] In many embodiments, at least two (orthogonal) cross-sectional dimensions / directions of the first power extraction heating element exceeds 5 mm, and in many embodiments the two dimensions exceed 10, 20, or even 50mm. The relatively large extension of the heating element 209 in the two dimensions may ensure efficient heating and thermal transfer to the support element 207. The large extension in the two dimensions allow for substantial eddy currents to be formed and indeed to be formed over a large area. This may ensure not only a substantial heating of the heating element 209 throughout a large area but also ensures that substantial and efficient thermal energy flow to the support element 207 can be achieved, and indeed can be achieved over a large area. Thus, a very efficient heat induction and transfer to the support element 207, and thus to the item to be heated can be achieved. 2024PF00482

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[0136] In many embodiments, no more than one cross-sectional dimension of the heating element 209 exceeds 5 cm, 10 cm, or 25 cm.

[0137] In many embodiments, a third cross-sectional dimension / direction of the heating element 209 (being orthogonal to the previously mentioned dimensions / directions of substantial extension) may not exceed 5 mm, or 3, 10, 20 mm in some embodiments. Thus, in contrast to the two other cross-sectional dimensions, the third dimension may be very small / narrow. Thus, the heating element 209 may be a thin planar (metallic) element. This may allow a highly advantageous arrangement and heating device in many embodiments. It may ensure a low profde embodiment and thus e.g. require very little additional height extension for the heating arrangement while still allowing a substantial and efficient heating. In many embodiments, it may facilitate production and manufacturing. For example, it may allow the heating element 209 to be formed from a single metal sheet, e.g. by the shape of the heating element 209 simply being stamped out from the metal sheet and attached to the support element 207.

[0138] In many embodiments, the heating element 209 may be substantially annular / ring shaped. For example, a circle may exist such that a distance from a center of the circle to the heating element 209 along any angle may deviate by no more than 5%, 10%, or 20% of a radius of the circle. Such an arrangement may typically provide an advantageous implementation and may typically provide an efficient generation of an area for flux to pass through as well as a sufficiently large area for efficient thermal coupling to the support element 207. It will typically be suitable for many different heating devices and appliances, such as pans or kettles.

[0139] In addition to the heating element 209, the heating apparatus / device may further comprise a heating element which does not have any electrical connections and from which no electrical power is extracted. However, this heating element, in the following also referred to as a non-power extraction heating element, is designed to have a substantial extension in at least two cross-sectional (orthogonal) dimensions / directions. In particular, the extension in at least two orthogonal cross-sectional dimensions / directions of the non-power extraction heating element exceed 50 mm. In many embodiments, an area of the non-power extraction heating element may be no less than 10cm2, 25cm2, 50cm2, or 100cm2.

[0140] In many embodiments, the non-power extraction heating element may be arranged to be within the loop formed by the heating element 209. In many embodiments, the non-power extraction heating element may be arranged concentrically within the heating element 209. An example of such an arrangement is shown in FIG. 4 which corresponds to the arrangement of FIGs. 2 and 3 but with an additional non-power extraction heating element 401 being positioned inside the loop formed by heating element 209.

[0141] The additional non-power extraction heating element may provide increased heating and improved thermal coupling / flow to the support element 207. In particular, it may allow heating to also be generated and provided within the area that is formed by the loop of the heating element 209 in order to 2024PF00482

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[0143] allow electrical power extraction. For example, in the example of FIG. 4, it allows heating to also be provided in the center of the pan / support element 207.

[0144] The approach may further allow facilitated production and manufacturing, and e.g. in many cases both the heating element 209 and the non-power extraction heating element 401 may be formed from a single metal sheet, e.g. by the shapes being stamped out from the metal sheet and attached to the support element 207. It may also allow a desirable arrangement with e.g. little additional height being required.

[0145] Further, in many scenarios the presence of the non-power extraction heating element 401 may result in an improved operation as it may affect the magnetic field itself. In particular, a centralized non-power extraction heating element 401 may in many cases carry eddy currents and the magnetic field lines may be attracted to the central metal thereby potentially improving the coupling.

[0146] In some embodiments, the heating apparatus may comprise a plurality of heating elements from which electrical power is extracted. In particular, the heating apparatus may further comprise a second power extraction heating element which is fixed relative to the support element 207 and which is coupled to the support element 207. The second power extraction heating element is also arranged to be heated by eddy currents in the presence of a varying electromagnetic field.

[0147] The second power extraction heating element is further arranged to form (together with the coupling to the power extracting circuit) at least one loop enclosing an area (which during operation receives a magnetic flux generated by the power transmitter). The second power extraction heating element is electrically coupled to the power extracting circuit 211 which is arranged to extract electrical power from the second power extraction heating element.

[0148] In some embodiments, the heating apparatus may further comprise a third, fourth, or more power extraction heating elements.

[0149] The comments and description previously provided for the first heating element 209 may equally apply to the second and further power extraction heating elements. In particular, the second (or further) power extraction heating element may have the same geometric constraints and design requirements as previously mentioned for the first heating element.

[0150] The electrical coupling from the multiple power extraction heating elements to the power extracting circuit 211 may be different in different embodiments. In many embodiments, the different power extraction heating elements may be coupled in series or parallel (or any combination thereof).

[0151] The arrangement of the different power extraction heating elements may be different in different embodiments and may be optimized for the preferences and requirements of the individual application. In many embodiments, the power extraction heating elements may be arranged concentrically. Thus, the second power extraction heating element may be positioned concentrically within the area / loop formed by the first power extraction heating elements (or vice versa). Such an arrangement may provide a particularly advantageous arrangement in many embodiments and scenarios. 2024PF00482

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[0153] FIG. 5 illustrates an example of an arrangement of heating elements for a heating apparatus. In particular, the approach described for FIGs. 2 and 3 may be modified to further comprise a second power extraction heating element 501 and the non-power extracting heating element 401. In the example, the second power extraction heating element 501 is arranged concentrically within the first power extraction heating element 209. Further, the non-power extracting heating element 401 is arranged concentrically within both the first and the second power extraction heating element 209, 501. In the example, all three heating elements are substantially annular / circular arrangements. Further, in the example, the couplings to the power extraction heating elements 209, 501 are simply coupled in parallel and fed to the power extracting circuit 211. It will be appreciated that in other embodiments, the power extraction heating elements 209, 501 may e.g. be coupled in series or may e.g. be coupled to different power extracting-supply circuits (e.g. comprising rectifiers, smoothing capacitors, voltage regulators) for e.g. combining at a later stage of the processing or to e.g. separately provide power to different circuits.

[0154] The specific example of FIG. 5 includes a relatively small primary heat generating surface / element in the form of the non-power extracting heating element 401 and two relatively large heat- and power generating surfaces in the form of the two power extraction heating elements 209, 501.

[0155] FIG. 6 illustrates another example in which, in comparison to the arrangement of FIG. 5, the non-power extracting heating element 401 covers a full circle without any missing internal areas / regions and with the arrangement including four power extraction heating elements 209, 501, 601. In comparison to the approach of FIG. 5, the arrangement of FIG. 6 includes double the number of power extraction heating elements 209, 501, 601 but with each of these being narrower than in the example of FIG. 5.

[0156] Another exemplary arrangement is provided in FIG. 7. The example corresponds to the example of FIG. 5 but with the ends of the power extraction heating elements 209, 501 exiting laterally from the formed loops / rings formed by the power extraction heating elements 209, 501 in order to facilitate the coupling / connection to the power extractor, or power extracting circuit, 211.

[0157] In some embodiments, a single power extraction heating element may be arranged in a spiral shape thereby forming at least two loops. Each loop forms a loop enclosing an area (for receiving a magnetic flux from a power transmitter). In this way, a planar arrangement with a single power extraction heating element may effectively form multiple windings of a power extracting coil thereby providing a more efficient extraction of electrical energy in many embodiments.

[0158] FIG. 8 illustrates an example of such an approach. In the example, the first power extraction heating element 209 is formed in a spiral geometry such that it effectively creates two loops which enclose differently sized areas. Specifically, effectively a larger outer loop 801 and a smaller inner loop 803 are formed. As a result, a larger emf is induced and present at the opposite end points 213 of the first power extraction heating element 209 to which the power extracting circuit 211 is coupled. 2024PF00482

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[0160] In the example of FIG. 8, a combined heat- and power generating surface, in the form of the first power extraction heating element 209, may effectively provide an effect corresponding to two windings.

[0161] In many embodiments, such as those illustrated in FIGs. 2-8, the power extraction heating element 209 and the non-power extraction heating element 401 may be provided in single layer, which specifically may be a thin layer having an extension not exceeding 5 mm, or in some cases 10mm. The heating elements may accordingly have significant extension in two (orthogonal) dimensions / directions while having a much (often 10 times or more) smaller extension in the third (orthogonal) dimension / direction, and in some embodiments such a property may further extend over a plurality, and typically all, of the heating elements. Thus, a total extension of the arrangement of all heating elements is in many embodiments very small, and specifically less than 5 (or 10) mm. Advantageously in many embodiments, all the heating elements are of equal thickness (and typically act as a single layer).

[0162] As an example, the heating element arrangement may be manufactured by stamping (or otherwise current / separating) the heating elements out of a sheet of (typically ferrous) metal, and in particular by stamping all the heating elements out of the same sheet of metal. The sheet of metal may have a depth of no more than 5 (or 10) mm. The stamped out heating element(s) may then be attached to the support element 207 to typically form a low profde heating arrangement.

[0163] The previous description has focused on approaches in which the support element 207 is an electrically isolating but thermally conducting element with the heating elements being directly attached to the support element 207.

[0164] However, in some embodiments, the heat / thermally conductive support element 207 may be electrically conductive or semi-conductive. In some embodiments, the heating apparatus may include an additional heat conductive element, henceforth for brevity referred to as the intermediate element, having the heat conductive support element and the first power extraction heating element fixed on opposite sides. The intermediate element has a substantially lower conductivity than the support element 207 (and of the heating elements) and has a conductivity no less than ten times, and often 100 or a 1000 times, lower than the support element 207. In many embodiments, the support element 207 may specifically be a conductive element that is at least partly formed by a metallic material. In contrast, the intermediate element may be formed by a ceramic material which is thermally conductive but electrically insulating. In many embodiments, the intermediate element may be formed by an aluminum oxide (A12O3) material.

[0165] An example of such an arrangement is illustrated in FIG. 9. The example corresponds to the example of FIG. 4 but with the support element 207 being formed by an electrically conductive material (specifically a metal) and with this and the heating elements 209, 401 being separated by an electrically isolating but thermally conducting intermediate element 901. A very attractive and typically low profile implementation may be achieved in many practical embodiments and implementations. 2024PF00482

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[0167] Thus, in many embodiments, an isolation layer may be provided which has a higher electrical resistance / lower conductivity than the heating elements and the support element. The electrically isolating layer may not provide a complete isolation but has a substantially lower conductivity than the heating elements and the support element. The layer / element may typically be a thin layer, and e.g. typically may have an extension in one dimension which is no more than 5mm, or possibly in some cases 10mm. The layer / element may typically have a good thermal conductivity which may typically be less than 1, 2, 5, 10, or in some cases even 100 W / mK.

[0168] In some embodiments, the structure / arrangement may further include a communication coil which in particular is suitable for communicating with the power transmitter. For example, the communication coil 205 may be implemented in a substantially planar arrangement which also includes one or more power extraction heating elements as well as possibly a non-power extraction heating element. In many embodiments, the communication coil may be arranged concentrically with the power extraction heating element(s).

[0169] An example of such an arrangement for a wirelessly power pan is illustrated in FIG. 10. In the example most of the center area is covered by a non-power extraction heating element 1001. Concentrically surrounding this, the arrangement includes four power extraction heating elements 1003 that are coupled to a power extracting circuit 211 as previously described (not explicitly illustrated in FIG. 10). Further, concentrically surrounding the power extraction heating elements 1003 is a communication coil 1005. The communication coil 1005 is typically formed by a number of very thin wires / conductors that are suitable for e.g. load modulating a carrier generated by a power transmitter communication coil. In particular, in many embodiments, the communication coil 1005 may be an NFC communication coil 1005.

[0170] It will be appreciated that the above description for clarity has described embodiments of the invention with reference to different functional circuits, units and processors. However, it will be apparent that any suitable distribution of functionality between different functional circuits, units or processors may be used without detracting from the invention. For example, functionality illustrated to be performed by separate processors or controllers may be performed by the same processor or controllers. Hence, references to specific functional units or circuits are only to be seen as references to suitable means for providing the described functionality rather than indicative of a strict logical or physical structure or organization.

[0171] The invention can be implemented in any suitable form including hardware, software, firmware or any combination of these. The invention may optionally be implemented at least partly as computer software running on one or more data processors and / or digital signal processors. The elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the invention may be implemented in a 2024PF00482

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[0173] single unit or may be physically and functionally distributed between different units, circuits and processors.

[0174] Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term comprising does not exclude the presence of other elements or steps.

[0175] Furthermore, although individually listed, a plurality of means, elements, circuits or method steps may be implemented by e.g. a single circuit, unit or processor. Additionally, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and / or advantageous. Also the inclusion of a feature in one category of claims does not imply a limitation to this category but rather indicates that the feature is equally applicable to other claim categories as appropriate. The inclusion of a feature in a dependent claim of one independent claim does not imply a limitation to this independent clam but rather indicates that the feature is equally applicable to other independent claims as appropriate. Furthermore, the order of features in the claims do not imply any specific order in which the features must be worked and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. In addition, singular references do not exclude a plurality. Thus, references to "a", "an", "first", "second" etc. do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example shall not be construed as limiting the scope of the claims in any way.

Claims

1. 2024PF004822.203.CLAIMS:4.Claim 1. A heating apparatus comprising:5.a thermally conductive support element (207) for supporting an item to be heated; at least a first power extraction heating element (209) fixed relative to the support element (207), the first power extraction heating element (209) being thermally coupled to the support element (207) and being arranged to be heated by eddy currents in the presence of a varying electromagnetic field;6.a power extracting circuit (211) electrically coupled to the first power extraction heating element (209) and arranged to extract electrical power from the first power extraction heating element (209); and7.wherein the first power extraction heating element (209) is arranged to form at least one loop enclosing an area.8.Claim 2. The heating apparatus of claim 1 wherein at least two cross-sectional dimensions of the first power extraction heating element (209) exceed 5 mm.9.Claim 3. The heating apparatus of claim 2 wherein a third cross-sectional dimension of the first power extraction heating element (209) does not exceed 5 mm.10.Claim 4. The heating apparatus of any previous claim wherein the first power extraction heating element (209) is substantially annular.11.Claim 5. The heating apparatus of any previous claim further comprising a second power extraction heating element (501, 601) fixed relative to the support element (207), the second power extraction heating element (501, 601) being thermally coupled to the support element (207) and being arranged to be heated by eddy currents in the presence of a varying electromagnetic field;12.wherein the power extracting circuit (211) is electrically coupled to the second power extraction heating element (501, 601) and arranged to extract electrical power from the second power extraction heating element (501, 601); and13.the second power extraction heating element (501, 601) is arranged to form at least one loop enclosing a second area.14.Claim 6. The heating apparatus of claim 5 wherein the first power extraction heating element (209) and the second power extraction heating element (501, 601) are arranged concentrically. 2024PF0048215.2116.Claim 7. The heating apparatus of any previous claim further comprising a heating element (401) having at least two cross-sectional dimensions exceeding 50 mm, the heating element (401) not having any electrical connections.17.Claim 8. The heating apparatus of claim 7 wherein the first power extraction heating element (209) and the heating element (401) are provided in single layer having an extension not exceeding 5 mm.18.Claim 9. The heating apparatus of any previous claim further comprising a thermally conductive element (901) having the thermally conductive support element (207) and the first power extraction heating element (209) fixed on opposing sides; and wherein an electric conductivity of the support element (207) exceeds that of the thermally conductive element (901) by a factor of no less than ten.19.Claim 10. The heating apparatus of any previous claim wherein the first power extraction heating element (209) is composed of a ferrous metal.20.Claim 11. The heating apparatus of any previous claim wherein the first power extraction heating element (209) is arranged in a spiral shape forming at least two loops.21.Claim 12. The heating apparatus of any previous claim further comprising a communication coil (205) arranged concentrically with the first power extraction heating element (209); and a communication circuit (203) coupled to the communication coil (205) and arranged to communicate using the communication coil (205).22.Claim 13. A wireless power heating system comprising:23.the heating apparatus of any previous claim; and24.a wireless power transmitter comprising a power transmitter coil arranged to generate the varying electromagnetic field.25.Claim 14. The wireless power heating system of claim 13 wherein the wireless power transmitter is a Ki power transmitter.26.Claim 15. A method of heating an item, the method comprising:27.providing a thermally conductive support element (207) for supporting an item to be heated;28.providing at least a power extraction heating element (209) fixed relative to the support element (207), the power extraction heating element (209) being thermally coupled to the support element (207) and being arranged to be heated by eddy currents in the presence of a varying electromagnetic field; 2024PF0048229.2230.a power extracting circuit (211) electrically coupled to the power extraction heating element (209) and extracting electrical power from the power extraction heating element (209); and wherein the power extraction heating element (209) forms at least one loop enclosing an area.

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