Wireless power transmission

Abstract

To provide a power transmitter that supports a changing power level in a wireless power transmission system and a method of operating the same.SOLUTION: A wireless power transmitter comprises a transmitter coil 103 to which a drive signal generated by a driver 201 is applied to generate a power transfer signal. A power loop controller 209 implements a power control loop for controlling the drive signal to adjust a power level of the power transfer signal in response to a power control error message received by a power receiver. A mode storage device 213 stores a plurality of power level modes for the power receiver. Each power level mode is associated with a reference power level for the power transfer signal. A mode circuit 211 adapts the drive signal to set the power level of the power transfer signal to a first reference value in response to reception of a mode request message by the receiver 207. The first reference value corresponds to the reference power level of the first power level mode indicated by the mode request message.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to the operation of a wireless power transmission system, and more particularly, but not limited to, a method for supporting changing power levels in a wireless power transmission system such as Qi. [Background technology]

[0002] Most modern electrical devices require dedicated electrical contacts to receive power from an external source. However, this tends to be impractical, as it requires the user to physically insert a connector or otherwise establish physical electrical contact. Typically, power requirements also vary considerably, and currently, most devices are provided with dedicated power supplies, resulting in a typical user having numerous different power supplies, each dedicated to a specific device. While the use of an internal battery can avoid the need for a wired connection to a power source during use, this only offers a partial solution as it requires recharging (or replacement) of the battery. Furthermore, using a battery can substantially increase the weight and potential cost and size of the device.

[0003] To provide a significantly improved user experience, it has been proposed to use a wireless power supply in which power is inductively transmitted from a transmitter coil in a power transmitter to a receiver coil in an individual device.

[0004] Power transmission via magnetic induction is a well-known concept and is mostly applied to transformers with 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 the two devices, wireless power transmission between them becomes possible based on the principle of loosely coupled transformers.

[0005] Such a configuration enables wireless power transmission to the device without the need for wired or physical electrical connections. In fact, to recharge or supply power from an external source, the device can simply be placed adjacent to or on top of the transmitter coil. For example, the power transmitter can be configured to have a horizontal surface on which the device can simply be placed to supply power.

[0006] Furthermore, such wireless power transmission configurations can be advantageously designed so that the power transmitter can be used with a range of power receivers. In particular, a wireless power transmission approach known as the Qi standard has been defined and is currently under further development. This approach allows power transmitters that meet the Qi standard to be used with power receivers that meet the Qi standard, without having to be from the same manufacturer or dedicated to each other. The Qi standard further includes several features that allow for adaptation of operation to specific power receivers (e.g., depending on a specific power drain).

[0007] The Qi standard was developed by the Wireless Power Consortium, and more detailed information can be found, for example, on their website (http: / / www.wirelesspowerconsortium.com / index.html), where the defined specifications can be found.

[0008] Qi was originally defined as low-power wireless power transmission in version 1.0, and was actually limited to lower power levels of less than 5W. This was extended to higher power levels in subsequent versions, and version 1.2, for example, provides compliance testing that addresses power levels up to 15W.

[0009] To control and adapt to power transmission, wireless power transmission systems typically implement a power control loop, in which the power receiver continuously sends power error control messages to the power transmitter during power transmission, and the power transmitter responds by increasing or decreasing the power level accordingly. Such a power control loop typically provides an efficient method for the power receiver to control the level of power transmitted from the power transmitter. However, the precise design of such a power control loop is difficult and involves many trade-offs that inherently result in suboptimal performance. For example, while it is desirable for the power control loop to respond quickly to changes in required power, it is also desirable for the loop to be stable and robust against noise.

[0010] Therefore, an improved approach for wireless power transmission would be particularly advantageous if it allows for increased flexibility, reduced cost, reduced complexity, improved support for a wider power range, improved transient power performance, improved adaptability, backward compatibility, improved power transmission operation, and / or improved performance. [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] Therefore, the present invention preferably seeks to mitigate, reduce, or eliminate one or more of the above-mentioned drawbacks, either individually or in any combination. [Means for solving the problem]

[0012] According to one aspect of the present invention, a power transmitter is provided for wirelessly supplying power to a power receiver via an electromagnetic power transmission signal, the power transmitter comprising: a receiver for receiving messages from a power receiver; an output circuit comprising a transmitter coil for generating a power transmission signal in response to a drive signal applied to an output circuit; a driver circuit for generating a drive signal; a power loop controller implementing a power control loop for controlling the drive signal to adjust the power level of the power transmission signal, wherein the power control loop is configured to modify the power level of the power transmission signal in response to a power control error message received from a power receiver; a mode memory device configured to store a plurality of power level modes for a power receiver, each power level mode associated with a reference power level of the power transmission signal; and a mode circuit configured to adapt a drive signal to set the power level of the power transmission signal to a first reference value in response to receiving a mode request message, wherein the first reference value corresponds to the reference power level of a first power level mode among a plurality of power level modes indicated in the mode request message.

[0013] The present invention can provide improved performance and / or improved power transmission in many scenarios. In many embodiments, improved and more efficient power transmission can be enabled across various power levels. This approach can, in many embodiments, particularly support, enable, improve, or facilitate high-power wireless power transmission.

[0014] In many embodiments, improved switching between different power levels can be achieved, and in particular, transient performance can be improved. This approach allows the system to take advantage of the benefits provided by precise power control loops while mitigating some of the drawbacks of such loops. In particular, stable and reliable power control operation can be combined with fast transient performance.

[0015] The use of specific power level modes and messaging from power receivers can, in particular, allow power control loop performance and constraints to be overridden at specific times to provide fast transient performance.

[0016] The reference power level for power level modes can be represented, for example, by any parameter of the drive signal or transmitter coil signal that affects the power level of the power transmission signal, specifically by the amount of power transmitted to the power receiver. Specifically, the reference power level can be the current, voltage, frequency, power, duty cycle and / or active duration (burst mode) of the drive signal, and / or the current, voltage, frequency, power, duty cycle and / or active duration (burst mode) of the transmitter coil signal. In many embodiments, the reference power level may be indicated by the coil current of the transmitter current.

[0017] The reference power level for power level mode may be a reference power level parameter that affects and / or reflects the power level of the power transmission signal.

[0018] Similarly, the first reference value can be represented by any parameter of the drive signal or transmitter coil signal that affects the power level of the power transmission signal, specifically the amount of energy transmitted to the power receiver. Specifically, the first reference value can be the current, voltage, frequency, power, duty cycle, and / or active duration (burst mode) of the drive signal, and / or the current, voltage, frequency, power, duty cycle, and / or active duration (burst mode) of the transmitter coil signal. In many embodiments, the first reference value may be indicated by the coil current of the transmitter current. The first reference value may be for the same parameters as the reference power level of the power level mode indicated in the mode request message, or for different parameters (in which case the mode circuit can convert between parameters).

[0019] The power loop controller can be configured to control the drive signal by adapting its parameters that affect the power level of the power transmission signal, such as the current, voltage, frequency, power, duty cycle, and / or active duration (burst mode) of the drive signal.

[0020] The parameters that affect the power level of the power transmission signal may specifically have a one-to-one monotonic relationship with the power level of the power transmission signal (at least within the operating range).

[0021] The receiver for receiving a message from the power receiver may sometimes be called a message receiver (for receiving a message from the power receiver).

[0022] According to an optional feature of the present invention, the period for adapting the drive signal to set the power level of the power transmission signal to a first reference value is less than the time constant of the power control loop.

[0023] This approach may enable a faster adaptation of the power transmission operation to changes in the power transmission operation.

[0024] According to an optional feature of the present invention, the mode storage device is configured to store a plurality of parameters related to at least one power level mode, the plurality of parameters including at least one reference power level representing the power level of the power transmission signal and at least one parameter value for at least one of the drive signal and the signal of the transmitter coil, the at least one parameter value being a value for at least one of the drive signal and the signal of the transmitter coil with respect to the power level of the power transmission signal indicated by the reference power level.

[0025] This can provide improved performance in many embodiments. For example, a power transmitter can store both reference power levels in the form of power extracted by a power receiver. Furthermore, a power transmitter can store signal parameter values ​​of a drive signal or transmitter coil signal that yields the corresponding power level of a power transmission signal. For example, it can store the frequency of a drive signal that generates a desired power level. This can be considered equivalent to a mode memory device that stores multiple reference power levels for a given power level mode, or it will be understood that the stored reference power levels for a given power level mode may comprise multiple elements.

[0026] According to an optional feature of the present invention, the power transmitter further comprises a detection circuit that detects a power transmission anomaly in response to a comparison between the current power level of the power transmission signal and a reference power level for the current power level mode among a plurality of power level modes.

[0027] This approach could enable improved operation, particularly by allowing the detection of anomalies such as failures, thereby enabling the system to respond to such situations.

[0028] In some embodiments, the detection circuit is configured to change power transmission parameters in response to the detection of a power transmission anomaly.

[0029] This can provide improved performance in many embodiments, enabling the system to compensate for anomalies such as potential failures. Specifically, the detection circuit can reduce the maximum power limit of the power transmission signal and / or terminate ongoing power transmission.

[0030] According to an optional feature of the present invention, the mode circuit is configured to determine a reference power level for at least some of the power level modes among a plurality of power level modes in relation to at least one of the parameter values ​​of the drive signal and the parameter values ​​of the power transmission signal characteristics during an initialization phase in which the power receiver passes through at least some power level modes, and the mode memory is configured to store the reference power levels for at least some power level modes.

[0031] This can provide particularly efficient operation in many embodiments and scenarios, for example, allowing a power transmitter to adapt to different power receivers without requiring pre-stored information.

[0032] The parameter values ​​for the drive signal and / or transmitter coil signal may be measured parameters or parameters set by the power transmitter during operation in the initialization phase. For example, the parameter values ​​may be the frequency, current, voltage, duty cycle, and power of the drive signal and / or transmitter coil signal during operation in power level mode during the initialization phase.

[0033] The measured values ​​of the drive signal characteristics and the power transmission signal characteristics may be measurements that enable the determination of appropriate parameters used to indicate a reference power level, such as the transmitter coil current.

[0034] According to an optional feature of the present invention, the initialization phase precedes the power transmission phase.

[0035] This can provide improved operation in many embodiments.

[0036] According to an optional feature of the present invention, the receiver is configured to receive a power receiver setting message from a power receiver, the power receiver setting message including power receiver setting parameters, and the mode circuit is configured to determine a reference power level for at least one of a plurality of power level modes, depending on the power receiver setting characteristics. This can provide improved operation in many embodiments. In many embodiments and scenarios, the power transmitter can be made to estimate a suitable reference power level for a particular power receiver with sufficient accuracy. This approach can be made to allow the power transmitter to adapt to a particular power receiver.

[0037] According to an optional feature of the present invention, the power receiver setting parameter includes at least one of the following: power receiver ID, power receiver type ID, power receiver coil characteristics, power receiver coil dimensional characteristics, and power receiver coil inductance characteristics.

[0038] These parameters can provide particularly advantageous adaptations in many embodiments.

[0039] According to an optional feature of the present invention, the mode circuit is configured to determine a coupling coefficient between a power transmitter coil and a power receiver coil of a power receiver based on power receiver setting parameters, and to determine a reference power level for at least one power level mode based on said coupling coefficient.

[0040] This can provide particularly advantageous operation and / or performance in many embodiments and scenarios.

[0041] According to an optional feature of the present invention, the mode circuit is configured to determine a power transfer function between at least one of the drive signal parameters and the transmitter coil signal parameters and the output power of the power receiver based on the power receiver setting parameters, and to determine a reference power level for the at least one power level mode based on the power transfer function.

[0042] This can provide particularly advantageous operation and / or performance in many embodiments and scenarios.

[0043] According to any feature of the present invention, the mode memory is configured to store a set of power level modes for different power receivers, and the mode circuit is configured to select from among the set of power level modes in response to an ID indication received from the power receiver. This can provide improved operation in many embodiments.

[0044] According to an optional feature of the present invention, the mode request message includes a timing indicator, and the mode circuit is configured to adapt the timing for setting the power level of the power transmission signal according to the timing indicator.

[0045] This can provide particularly advantageous operation and / or performance in many embodiments and scenarios. The timing indicator can indicate one or more changes in the power level mode by the power receiver.

[0046] According to an optional feature of the present invention, the mode request message is received during the power transmission phase.

[0047] This can provide particularly advantageous operation and / or performance in many embodiments and scenarios.

[0048] According to another aspect of the present invention, a method of operation is provided for a power transmitter for wirelessly supplying power to a power receiver via an electromagnetic power transmission signal, the power transmitter having an output circuit including a transmitter coil for generating a power transmission signal in response to a drive signal applied to the output circuit, the method comprising: receiving a message from the power receiver; generating a drive signal; operating a power control loop to control the drive signal and adjust the power level of the power transmission signal, the power control loop configured to change the power level of the power transmission signal in response to a power control error message received from the power receiver; storing a plurality of power level modes for the power receiver in a mode memory, each power level mode associated with a reference power level for the power transmission signal; and adapting the drive signal to set the power level of the power transmission signal to a first reference value in response to receiving a mode request message, the first reference value corresponding to a reference power level for a first power level mode among a plurality of power level modes indicated in the mode request message.

[0049] According to another aspect of the present invention, a wireless power transmission system is provided which includes a power transmitter for wirelessly supplying power to a power receiver via an electromagnetic power transmission signal, the power transmitter comprising: a receiver for receiving messages from the power receiver; an output circuit including a transmitter coil for generating the power transmission signal in response to a drive signal applied to an output circuit; a drive circuit for generating the drive signal; and a power loop control device for controlling the drive signal to adjust the power level of the power transmission signal, wherein the power control loop is configured to modify the power level of the power transmission signal in response to a power control error message received from the power receiver; and a mode memory device configured to store a plurality of power level modes for the power receiver, each power level mode being associated with a reference power level for the power transmission signal; and a mode circuit configured to adapt the drive signal to set the power level of the power transmission signal to a first reference value in response to receiving a mode request message, wherein the first reference value corresponds to a reference power level for a first power level mode among a plurality of power level modes indicated in the mode request message.

[0050] These and other aspects, features and advantages of the present invention will become apparent from and be described with reference to the embodiments described below. [Brief explanation of the drawing]

[0051] Embodiments of the present invention will be described with reference to the drawings, merely as examples. [Figure 1] A figure showing examples of elements in a power transmission system according to several embodiments of the present invention. [Figure 2] A diagram showing an example of the elements of a power transmitter according to several embodiments of the present invention. [Figure 3] A diagram showing an example of the elements of the output stage of a power transmitter. [Figure 4] A diagram showing an example of the elements of the output stage of a power transmitter. [Figure 5]A figure showing an example of the elements of a power receiver according to several embodiments of the present invention. [Figure 6] Figure 1 shows an example of a power control loop in a power transmission system. [Figure 7] Figure 1 shows an example of power load fluctuations in a power transmission system. [Figure 8] Figure 1 shows an example of a model of the power transmission path in a power transmission system. [Modes for carrying out the invention]

[0052] The following description focuses on embodiments of the present invention applicable to wireless power transmission systems that utilize power transmission approaches such as those known from the Qi standard. However, it will be understood that the present invention is not limited to this application and may be applied to many other wireless power transmission systems.

[0053] Figure 1 shows an example of a power transmission system according to several embodiments of the present invention. The power transmission system includes a power transmitter 101 including (or coupled to) a transmitter coil / inductor 103. The system further includes a power receiver 105 including (or coupled to) a receiver coil / inductor 107.

[0054] The system provides an electromagnetic power transmission signal that can inductively transmit power from a power transmitter 101 to a power receiver 105. Specifically, the power transmitter 101 generates an electromagnetic signal, which is propagated as magnetic flux by a transmitter coil or inductor 103 (typically part of an output circuit in the form of a resonant or tank circuit). The power transmission signal may correspond to an electromagnetic power transmission component representing energy transmission from the power transmitter to the power receiver, or it may be considered to correspond to a component of the generated electromagnetic field that transmits power from the power transmitter to the power receiver. For example, if there is no load on the receiver coil 107, no power is extracted by the power receiver from the generated electromagnetic field (apart from losses). In such a scenario, driving the transmitter coil 103 can generate an electromagnetic field with potentially high electric field strength, but the power level of the power transmission signal will be zero (apart from losses). In some situations where foreign matter is present, the power transmission signal can be considered to include a component corresponding to power transmission to the foreign matter, and therefore the power transmission signal can be considered to correspond to the power extracted from the electromagnetic field generated by the power transmitter.

[0055] The power transmission signal may typically have a frequency between approximately 20 kHz and 500 kHz, and for Qi-compatible systems, it is typically in the range of 95 kHz to 205 kHz (or, for example, for high-power kitchen applications, the frequency may typically be in the range of 20 kHz to 80 kHz). The transmitter coil 103 and the receiving coil 107 are loosely coupled, and therefore the receiving coil 107 picks up (at least a portion of) the power transmission signal from the power transmitter 101. Thus, power is transmitted from the power transmitter 101 to the power receiver 105 via radio inductive coupling from the transmitter coil 103 to the receiving coil 107. The term power transmission signal is primarily used to refer to the inductive signal / magnetic field (magnetic flux signal) between the transmitter coil 103 and the power receiving coil 107.

[0056] In this embodiment, the power receiver 105 is specifically a power receiver that receives power via a receiver coil 107. However, in other embodiments, the power receiver 105 may include a metal element, such as a metal heating element, in which case the power transmission signal directly induces eddy currents that result in direct heating of the element.

[0057] The system is configured to transmit substantial power levels, and specifically in many embodiments, the power transmitter can support power levels of 500mW, 1W, 5W, 50W, 100W, or more than 500W. For example, in Qi-enabled applications, power transmission typically ranges from 1 to 5W for low-power applications (baseline power profile), up to 15W for Qi standard version 1.2, up to 100W for high-power applications such as power tools, laptops, drones, and robots, and can range from 100W to over 1000W for very high-power applications such as high-power applications supported by the Cordless Kitchen Standard developed by the Wireless Power Consortium.

[0058] The operation of the power transmitter 101 and power receiver 105 will be described with particular reference to embodiments that generally conform to the Qi standard (except for modifications and extensions described herein or resulting therefrom) or are suitable for high-power kitchen specifications developed by the Wireless Power Transmission Consortium. In particular, the power transmitter 101 and power receiver 105 conform to or are substantially compatible with elements of Qi standard version 1.0, 1.1, or 1.2, or are suitable for higher-power cordless kitchen specifications (except for modifications and extensions described herein or resulting therefrom).

[0059] Figure 2 shows the elements of the power transmitter 101 in Figure 1 in more detail.

[0060] The power transmitter 101 includes a driver 201 capable of generating a drive signal, which is supplied to an output circuit, which in this example is a resonant circuit formed by a transmitter coil 103 and a transmitter capacitor 203. The transmitter coil 103 is driven by the drive signal, thereby generating an electromagnetic field. Thus, an electromagnetic power transmission signal is generated that provides power transmission to the power receiver 105. The power transmission signal is supplied (at least) during the power transmission phase.

[0061] The driver 201 is a drive circuit, typically in the form of an inverter that generates an AC signal from a DC voltage. The output of the driver 201 is usually a switch bridge that generates the drive signal by the proper switching of the switches of the switch bridge. Figure 3 shows a half-bridge switch bridge / inverter. Switches S1 and S2 are controlled so that they are never closed at the same time. Alternately, S1 is closed while S2 is open, and S2 is closed while S1 is open. The switches are opened and closed at the desired frequency, thereby generating an AC signal at the output. Typically, the output of the inverter is connected to a transmitter inductor via a resonant capacitor. Figure 4 shows a full-bridge switch bridge / inverter. Switches S1 and S2 are controlled so that they are never closed at the same time. Switches S3 and S4 are controlled so that they are never closed at the same time. Alternately, switches S1 and S4 are closed while S2 and S3 are open, and switches S2 and S3 are closed while S1 and S4 are open, thereby generating a square wave signal at the output. The switches are opened and closed at the desired frequency.

[0062] In some implementations, S1 and S3 may be open and S2 and S4 closed for part of the period, and vice versa for other parts of the period. This is known as phase control. Such an approach generates a square wave with a zero level in between. The drive circuit is implemented using discrete electronic components, and the output circuit is formed by solid-state switches such as transistors. However, it will be understood that other implementations are possible, including, for example, forming the output circuit using integrated switches or mechanical switches.

[0063] The drive circuit can be implemented as an integrated circuit, such as an application-specific integrated circuit (ASIC). In some embodiments, the circuit may be implemented as a programmed processing unit, such as firmware or software running on a suitable processor, such as a central processing unit, a digital signal processing unit, or a microcontroller. In such embodiments, it will be understood that the processing unit may include on-board or external memory, a clock drive circuit, interface circuits, user interface circuits, and so on. Such circuits may further be implemented as an integrated circuit and / or discrete electronic circuit as part of the processing unit.

[0064] Therefore, the driver 201 generates a drive signal for the output resonant circuit and thus for the transmitter coil 103. The drive signal causes current to flow through the transmitter coil, thereby generating an electromagnetic power transmission signal. The drive signal typically has a (substantially) constant voltage amplitude for a given power transmission configuration. In the example, this constant voltage amplitude is achieved by setting a constant rail voltage for the driver's output circuit, i.e., the rail voltage V for the bridge in Figures 3 and 4 is constant for a given power transmission configuration. Switching by the bridge transistor switches the output voltage between 0 and V for a half-bridge and between V and -V for a full-bridge, respectively. Therefore, in the example, the power transmitter can be set to have a rail voltage that is constant for any given power transmission configuration, but (in some cases) varies between power transmission configurations.

[0065] The power transmitter 101 further comprises a power transmitter controller 205 configured to control the operation of the power transmitter 101 according to a desired operating principle. Specifically, the power transmitter 101 may include many of the functions required to perform power control in accordance with the Qi standard, including interacting with a power receiver and providing a user interface, as appropriate for a particular application and standard.

[0066] The power transmitter 101 further comprises a first communicator 207 configured to receive data and messages from the power receiver 105 (as will be understood by those skilled in the art, the data messages may provide one or more bits of information). In this example, the power receiver 105 is configured to load-modulate the power transmission signal generated by the transmitter coil 103, and the first communicator 207 is configured to sense fluctuations in the voltage and / or current of the transmitter coil 103 and demodulate the load modulation based on these. Those skilled in the art are familiar with the principles of load modulation, such as those used in Qi wireless power transmission systems, and therefore will not be described in further detail.

[0067] The first communication device 207 may be further configured to transmit data to a power receiver by specifically modulating the drive signal and thus the power transmission signal using, for example, frequency, amplitude, and / or phase modulation.

[0068] It will be understood that other approaches for communicating data between the power transmitter 101 and the power receiver 105 may be used in other embodiments. For example, in some embodiments, communication may be performed using a separate communication coil or a separate communication channel which can actually be achieved using the transmitter coil 103. For example, in some embodiments, near-field communication may be implemented, or a high-frequency carrier (e.g., having a carrier frequency of 13.56 MHz) may be superimposed on the power transmission signal.

[0069] Figure 5 shows some exemplary elements of the power receiver 105. The receiver coil 107 is coupled to a power receiver controller 501 that couples the receiver coil 107 to a load 503. In many embodiments, the receiver coil 107 is part of a power receiver input circuit that also includes a capacitor to form a resonant circuit with the receiver coil 107. The power receiver controller 501 includes a power control path that converts the power extracted by the receiver coil 107 into a power supply suitable for the load. Furthermore, the power receiver controller 501 may include various power receiver controller functions required to perform power transmission, in particular functions required to perform power transmission according to the Qi standard.

[0070] The power receiver 105 further comprises a second communicator 505 configured to receive data transmitted from the power transmitter 101. In this embodiment, the second communicator 505 is configured to appropriately demodulate the amplitude, frequency, and / or phase modulation of the power transmission signal in order to acquire the data transmitted from the power transmitter.

[0071] The second communication device 505 is further configured to transmit data to the power transmitter 101 by changing the load of the receiver coil 107 in accordance with the data to be transmitted to the power transmitter 101. The load changes are then detected and demodulated by the power transmitter 101, as is known to those skilled in the art.

[0072] As mentioned above, in other embodiments, other communication methods can be used, such as using a separate, dedicated short-range communication approach like NFC.

[0073] The power transmitter and power receiver further include functions for implementing a power control loop to dynamically adapt the power level of the power transmission signal during the power transmission phase. The power receiver can continuously monitor the received power level and compare it to a desired power level. It can also transmit a power control error message, and the power transmitter can increase or decrease the power level by changing the characteristics of the drive signal.

[0074] In particular, the power transmitter includes a power loop controller 209 configured to control the power level of the power transmission signal by adjusting the parameters / characteristics of the drive signal. The power loop controller 209 can adjust parameters such as the drive signal current, voltage, frequency, duty cycle, and active duration (burst mode), thereby changing the power level of the power transmission signal.

[0075] The power loop controller 209 can be implemented as an integrated circuit, such as an application-specific integrated circuit (ASIC). In some embodiments, the power loop controller 209 may be implemented as a programmed processing unit, such as firmware or software running on a suitable processor, such as a central processing unit, a digital signal processing unit, or a microcontroller. In such embodiments, it will be understood that the processing unit may include on-board or external memory, clock drive circuits, interface circuits, user interface circuits, etc. Such circuits may further be implemented as integrated circuits and / or discrete electronic circuits as part of the processing unit.

[0076] In some embodiments, the power loop controller 209 may be implemented partially or completely as a separate electronic circuit. In different embodiments, the power loop controller may be implemented as an analog electronic circuit, a digital electronic circuit, or a mixed analog circuit.

[0077] It will be understood that in different embodiments, different parameters can be used to represent the power level of a power transmission signal. For example, in many embodiments, the power level of a power transmission signal can be represented by the characteristics or parameters of the transmitter coil signal, such as the current, voltage, frequency, duty cycle, and / or power of the signal from the transmitter coil 103. In many embodiments, the power level of a power transmission signal may be given and represented by the coil current for the transmitter coil 103. In many embodiments, the power control loop can control the power level of a power transmission signal, specifically by controlling the level of coil current passing through the transmitter coil 103.

[0078] In some embodiments, the power level of the power transmission signal can be specifically represented by the characteristics or parameters of the drive signal, such as the current, voltage, frequency, duty cycle, active duration, and / or power of the drive signal.

[0079] For example, increasing the current or duty cycle of the drive signal directly affects the signal from the transmitter coil 103 and, consequently, the resulting power transmission signal, thereby increasing the power level of the power transmission signal.

[0080] In fact, the power level of a power transmission signal can depend on several parameters, and in various embodiments, any such parameters can be used to represent and / or control the power level of the power transmission signal. It will also be understood that different parameters may be used to represent the power level of a power transmission signal. For example, a power receiver and a power transmitter may use different parameters to represent the power level of the power transmission signal (e.g., the power transmitter may use the current of the transmitter coil 103, and the power receiver may use the extracted power level). In such embodiments, conversions between different parameters and representations may be used, for example, or data related to one parameter may be adapted by making a relative change to another parameter.

[0081] It will also be understood that the parameters controlled and adapted by the power control loop may be modified directly or indirectly by changing other parameters. For example, the power control loop can control the coil current for the transmitter coil 103, which can be changed to a desired value, for example, by changing the frequency of the drive signal.

[0082] Figure 6 shows an example of a functional configuration of an exemplary power control loop that could be adopted in the system shown in Figure 1.

[0083] In particular, the coil current I txc The coil current can be controlled, meaning it can be considered a loop output or loop variable. txc This corresponds to the power level of the power transmission signal. Specifically, the magnetic flux and magnetic field strength generated by the transmitter coil 103 are directly supplied by the coil current, and therefore the signal induced in the receiver coil 107 is directly supplied by the transmitter coil current.

[0084] Thus, the loop includes a power path from the transmitter coil current to the power level extracted by the power receiver 105. This path includes the generation of the electromagnetic flux of the power transmission signal, the induction of the signal in the power receiver coil, and the power receiver power path. The extracted power (e.g., supplied to the load 503) is compared by the power receiver 105 to a desired (current) reference power level PWR REF. Based on the comparison power control error index, an ERR is generated and transmitted to the power transmitter 101 in a power control error message.

[0085] The power transmitter 101 controls the coil current I according to the power control error index. txc It has a function to adapt to the power level of the power transmission signal, specifically the coil current I txcThe changes are relative, and therefore the control loop can increase or decrease the power level from the current level depending on the power control error index / message. The relative changes in power level / coil current correspond to including integral function 603 within the power control loop.

[0086] Furthermore, the power loop controller 209 and the power transmitter implement a specific power modification circuit 605 for changing the power level according to a power control error index. For example, a power control error message may request that the power level be increased by a given relative amount, for example, 2%. In response, the power modification circuit 605 controls the coil current I txc We can decide that it should be increased by 2% and proceed with implementing this change.

[0087] In many embodiments, the power level can be adapted by changing the characteristics / parameters of the drive signal. Therefore, the power modification circuit 605 may include a circuit for changing the parameters of the drive signal, and as a result, this can affect the power level, particularly the coil current I txc To produce the desired change in [the specified location].

[0088] Specifically, in many embodiments, the output circuit of the power transmitter and the input circuit of the power receiver include a resonant circuit, and the power transmission signal and coil current I txc The power level is controlled by changing the drive frequency of the drive signal to approach or move away from the resonant frequency. In this way, by changing the frequency to approach the resonant frequency, the coil current I txc This can lead to an increase in [the number of people involved].

[0089] Other parameters of the drive signal that can be modified alternatively or additionally include the drive signal's current, voltage, power, duty cycle, or duration. Increasing any of these increases the power level of the power transmission signal, while decreasing them decreases the power level.

[0090] In some embodiments, the power change circuit 605 can include a direct correspondence between the drive signal parameters and the power transmission signal level (including coil current I txc ). For example, when a request to increase the power level by 2% is received, the power change circuit 605 can directly change the drive signal frequency or current by a certain amount. Such a direct correspondence can be based on, for example, a look-up table generated during the manufacturing or calibration process.

[0091] In many embodiments, the power change circuit 605 may include an internal loop that controls the drive signal parameters to effect a desired change in the power level of the power transmission signal. For example, in response to a received error power control message, an internal circuit may be implemented to change a reference value for, for example, coil current I txc . And the internal loop can adjust, for example, the drive signal frequency until the actual coil current I txc equals the desired new value.

[0092] Also, it will be understood that in many embodiments, the power level may be the effective power level or the active power level. However, in other embodiments, the power level considered may be the complex power level, the reactive power level, or the apparent power level.

[0093] The power control loop provides a very effective and reliable approach for the power receiver to control the power transmission operation. For example, it enables the power receiver to continuously adapt the transmitted power level, for example, to maintain a desired speed with respect to a load in the form of a motor.

[0094] The system of FIG. 1 further includes additional features for controlling the operation of the power control loop in specific situations, thereby providing improved operation in many scenarios.

[0095] Specifically, in a system, a power receiver may have multiple power level modes related to power transmission. More specifically, a power receiver may be associated with a set / multiple power level modes, each of which is linked to a reference power level for a power transmission signal. A power receiver may be configured to operate in different discrete modes, each of which has a given power level requirement from the power transmission signal. For example, a power receiver in the form of a blender may have, for example, five different motor speed settings, and thus each of these may be associated with five different operating modes, each extracting a different amount of power from the power transmission signal.

[0096] The power transmitter 101 includes a mode circuit 211 coupled to a power loop controller 209 and a mode storage device 213. The mode storage device 213 may be configured to store data for different power level modes. Specifically, the mode storage device 213 is configured to store a set of power level modes for a power receiver, where each power level mode is associated with a reference power level for a power transmission signal.

[0097] The mode circuit 211 can be implemented as an integrated circuit, such as an application-specific integrated circuit (ASIC). In some embodiments, the mode circuit 211 can be implemented as a programmed processing unit, such as firmware or software, running on a suitable processor, such as a central processing unit, a digital signal processing unit, or a microcontroller. In such embodiments, it will be understood that the processing unit may include on-board or external memory, clock drive circuits, interface circuits, user interface circuits, etc. Such circuits may further be implemented as an integrated circuit and / or discrete electronic circuit as part of the processing unit.

[0098] In some embodiments, the mode circuit 211 may be implemented partially or completely as a separate electronic circuit. In different embodiments, the power loop controller may be implemented as an analog electronic circuit, a digital electronic circuit, or a mixed analog circuit.

[0099] The power level mode can be represented by different parameters in different embodiments, and any suitable parameters that can indicate a power level can be used. For example, the reference power level can be represented by a value indicating the actual load provided to the load 503 by the power receiver. In other embodiments, the reference power level may be represented by the nominal power extracted from the power receiver for nominal operating conditions such as the absence of objects and the power transmitter and power receiver being in nominal positions relative to each other. In yet another embodiment, the reference power level may be represented by a value of a loop variable controlled by, for example, a reference coil current value for a given mode. In yet another embodiment, the reference power level can be represented by a value of a power transmitter parameter controlled to provide a desired power level. In many embodiments, the reference power level can be represented by values ​​of characteristics of the drive signal, such as the drive signal current, voltage, frequency, duty cycle, and active duration (burst mode). All of these parameters can reflect power levels in various embodiments, and changes in the values ​​of such parameters can affect the power level of the power transmission signal. It will also be understood that in some embodiments, combinations of parameters may be used (for example, using different parameters for different power level modes).

[0100] In the system, the power receiver can operate in separate sets of power level modes, and the mode memory can store a reference power level for each mode.

[0101] The system may have a power receiver that switches to a different mode, and in connection with this, it may send a message to the power transmitter to notify it of the mode change. Specifically, the power receiver may send a mode request message that indicates the power level mode to which it is currently (or to which it wishes to) switch. It will be understood that any form of indicator may be used. For example, power level modes may be associated with individual IDs, and the mode request message may include the ID of the power level mode to which the power receiver wishes to switch.

[0102] When the receiver 207 receives a mode request message, it forwards the ID to the mode circuit 211, which then accesses the mode memory 213 to obtain the reference power level for the power level mode specified by the ID. The mode circuit 211 is configured to adapt the drive signal to set the power level of the power transmission signal to this reference value, that is, it can adapt the drive signal so that a power transmission signal having a value corresponding to the acquired reference value is obtained as a result.

[0103] The reference value can be expressed by any appropriate value, specifically, the coil current I txc It will be understood that the power level of the power transmission signal can be represented by any value or parameter that affects it. The value can be adapted directly or indirectly by adapting, for example, the current, voltage, frequency, duty cycle, and active duration (burst mode) of the drive signal. In fact, in some embodiments, the values ​​of these parameters may be considered as reference values ​​themselves that are set by the mode circuit 211 and affect the power level of the power transmission signal.

[0104] The first reference value depends on the reference power level for the indicated power level mode. Therefore, upon receiving a mode request message, the mode circuit 211 can obtain the reference power level for the power level mode indicated in the mode request message. From this reference power level, it can then determine a reference value for a given parameter related to the power level of the power transmission signal (the power level of the power transmission signal depends on the value of the parameter for which the first reference value is determined). The first reference value may be determined in particular for a loop parameter, which is a parameter representing the signal value at a certain point in the loop. The mode circuit 211 can then set the parameter of the drive signal such that the parameter becomes the first reference value.

[0105] In many embodiments, this can be done directly. For example, in many embodiments, the reference value may be determined directly for parameters of the drive signal, such as the drive signal current, voltage, frequency, duty cycle, and active duration (burst mode). The mode circuit 211 may then proceed to directly set the drive signal to the reference value. For example, the power receiver can transition to a specific power level mode and transmit a mode request message indicating this mode. For this mode, the mode circuit 211 can directly determine that a reference power level corresponding to a given drive signal frequency is stored, and can immediately change the drive signal frequency to this value without considering the current value of the frequency (or any other value). For example, assuming that the power transmission resonant circuit is tuned to, for example, 100 kHz, a mode request message indicating mode 1 may cause the mode circuit 211 to set the drive signal frequency to 150 kHz, a mode request message indicating mode 2 may cause the mode circuit 211 to set the drive signal frequency to 160 kHz, and a mode request message indicating mode 3 may cause the mode circuit 211 to set the drive signal frequency to 170 kHz.

[0106] In some embodiments, the reference value may be determined for a parameter other than the drive signal parameter itself. For example, it may be specifically the coil current I txc The parameters of the transmitter coil signal may be such as the following. In such cases, the mode circuit 211 can adapt the parameters of the drive signal to obtain desired parameter values ​​for the transmitter coil signal. In some embodiments, this may be, for example, the frequency of the drive signal and the coil current I txc This can be achieved by the mode circuit 211 using a direct relationship or function between the characteristics to which the drive signal is adapted and the parameters of the transmitter coil signal, such as a direct relationship between the two. This relationship can be stored, for example, in a lookup table. However, in many embodiments, it is difficult to determine such a relationship, and the power transmitter can implement, for example, a high-speed internal loop. For example, coil current I txc The frequency of the drive signal is measured and can be compared with a desired first reference value, and the coil current I txc It can be quickly modified / adapted to produce the desired value.

[0107] In many embodiments, the stored reference power level may be directly represented by a first reference value, i.e., the mode circuit 211 may directly acquire the reference power level of the requested power level mode and use this as the reference value, i.e., the reference parameter may be directly set to this value. For example, in many embodiments, the mode memory device 213 may directly store the frequency for each of the power level modes, and when a mode request message is received, the stored frequency value can be directly extracted and the drive signal can be set to this frequency. In other embodiments, some conversions may be required, which can be achieved, for example, using a lookup table in which data can be registered during the calibration phase.

[0108] In an embodiment, the mode memory can store multiple parameters for each power level mode, such as both drive signal parameters and extracted power values. Thus, in such a case, the reference power level may include multiple components, or equivalently, the mode memory can store multiple reference power levels for each power level mode. In such an embodiment, the mode circuit 211 may use appropriate parameter values, or may use multiple parameter values. For example, if a mode request message indicates that the power receiver is switching to a power level mode that extracts, for example, 500W, the mode circuit 211 can identify the power level mode corresponding to the extracted power of 500W and retrieve the drive frequency stored for this power level mode.

[0109] This approach can provide a system that can adapt very quickly to different operating modes. Mode request messages can be sent during the power transmission phase, thus providing a means to rapidly change the power transmission operating point. Typically, power adaptation is achieved using power loop control, which, while adapted to provide efficient operation, is typically relatively slow to provide reliable performance. The described operation provides a means to override the power control loop, specifically, the power control loop can be dynamically changed / reinitialized to a new operating point to match the new power level mode during the power transmission phase.

[0110] Therefore, the mode circuit 211 can be configured to adapt the drive signal by changing the power control loop variables in response to the reception of a mode request message.

[0111] The mode circuit 211 is configured to set the power level of the power transmission signal to a first reference value in response to the reception of a mode request message. The power level of the power transmission signal is a state variable of the power control loop, and therefore the mode circuit 211 is configured to set the state variable of the power control loop to a reference value in response to the reception of a mode request message, and the reference value depends on the mode request message, and more specifically, on the power level mode indicated in the mode request message.

[0112] Signal adaptation may be independent of the operation of the power control loop, and therefore, in response to a mode request message, this approach may override the operation of the power control loop and reinitialize the operation for the new power level mode.

[0113] In some embodiments, the mode circuit 211 may be configured to change a power control loop state variable in response to receiving a mode request message, so as to adapt the drive signal to set the power level of the power transmission signal to a first reference value, the first reference value corresponding to the reference power level of a first power level mode among a plurality of power level modes indicated in the mode request message.

[0114] In some embodiments, the mode circuit 211 may be configured to adapt a drive signal to set the power level of a power transmission signal to a first reference value in response to the reception of a mode request message, the first reference value corresponding to the reference power level of a first power level mode among a plurality of power level modes indicated in the mode request message, and the adaptation includes changing a state variable of the power control loop.

[0115] In some embodiments, the mode circuit 211 may be configured to adapt the drive signal by changing a state variable in the power control loop to set the power level of the power transmission signal to a first reference value in response to the reception of a mode request message, the first reference value corresponding to the reference power level of a first power level mode among a plurality of power level modes indicated in the mode request message.

[0116] In some embodiments, the mode circuit 211 may be configured to adapt the drive signal by changing a state variable in the power control loop to set the power level of the power transmission signal to a first reference value in response to the reception of a mode request message, the first reference value corresponding to the reference power level of a first power level mode among a plurality of power level modes indicated in the mode request message.

[0117] The mode circuit 211 may be configured to override or replace the current value of the loop state variable with a reference value that depends on the power level mode indicated in the mode request message.

[0118] Adaptation of drive signals / setting of power transmission signal power levels / changes of power transmission signal power levels can be faster than what is achievable by the power control loop. The time constant / period for adapting / setting the power transmission signal power level to a reference value in response to a mode request message can be shorter than the time constant / period of the power control loop. In some embodiments, the power level setting may be a step change.

[0119] In many embodiments, the time constant of the power control loop is 250 msec or more, 500 msec or more, or 1 second or more, while the power level setting in response to the mode request message can be for a shorter period, specifically less than 100 msec, less than 250 msec, or less than 500 msec, respectively.

[0120] In many embodiments, the period for adapting the drive signal to set the power level is less than the time constant of the power control loop, and in many embodiments, this may be less than 50% or less than 25% of the time constant. This period may be the delay from when the mode request message is received until the power level of the power transmission signal is set to a first reference value (specifically, until it reaches the first reference value). The time constant of the control loop reflects how quickly the loop responds to changes. The time constant may be the period until a loop variable (specifically, such as the power level of the power transmission signal) reaches 63.2% of its final (steady-state) value following a step change.

[0121] As will be discussed in more detail later, it will be understood that different approaches can be used for power transmitters to determine and store power level modes and associated reference levels.

[0122] In some embodiments, power level modes and reference power levels may be stored for multiple power receivers. Therefore, the mode storage device 213 may be configured to store sets of power level modes for different power receivers.

[0123] When initializing the power transmission operation (or at any appropriate time), the power receiver can transmit a power receiver indicator. The mode circuit 211 / mode memory 213 can then proceed to retrieve a set of power level modes that match a specific ID.

[0124] In some embodiments, the ID may be a unique device ID. This can be particularly useful in embodiments where, for example, the stored power level mode and reference power level are determined by individual initialization using each device. For example, when a new power receiver is detected, the power transmitter can start an initialization routine that determines the power level mode and reference power level. The next time a power receiver is detected, the power transmitter can proceed to use already stored values ​​without performing the initialization process. The power transmitter can then gradually accumulate data for the appropriate power receiver, enabling the use of functions for various power receivers with less overhead.

[0125] Alternatively or additionally, the ID may be a type ID indicating, for example, the model, manufacturer, etc., of the power receiver. The power transmitter may store power level mode data for various different types of equipment, and upon receiving a type ID, it may select power level mode data that matches the received ID.

[0126] In some embodiments, the power level mode and reference power level data may be based on an initialization phase performed by the power transmitter and power receiver.

[0127] For example, in some embodiments, the initialization of a new power transmission (for example, only for power receivers where power level mode data is not stored) may first include performing a process to determine a reference value to be used during operation. During this initialization phase, the power receiver may go through different power level modes, and for each power level mode, the mode circuit 211 may determine a value representing the power level and store this as the reference power level for that mode.

[0128] For example, a power receiver can apply predetermined timings to step through power level modes, such as operating in each mode for 10 seconds before switching to the next mode. Alternatively, the power receiver can send a message when switching to the next mode, or the power transmitter can send a message requesting that the next mode be applied.

[0129] For each power level mode, the power transmitter can operate the power control loop to reach a stable state. Once a stable state is reached, the power transmitter sets the desired parameter used to represent the power level of the power transmission signal, for example, the coil current I txc Alternatively, values ​​such as the drive signal frequency can be measured. This value can then be stored as a reference power level for that mode.

[0130] The power receiver can then switch to the next power level mode, for example, at the request of the power transmitter, and this process can be repeated.

[0131] This approach can typically be implemented by having the power receiver sequentially traverse power level modes, typically from lower power levels to higher power levels. This can reduce the risk of undesirable overvoltage conditions, for example.

[0132] The initialization process may typically be performed as part of the power transmission initialization and therefore can be performed before the power transmission phase.

[0133] As a specific example, in an air fryer, a kitchen appliance that uses a convection mechanism to circulate hot air around food for cooking, the heating element may be switched on and off. This typically results in very large load steps, such as 50-1200W, which will be repeated during the operation of the device to maintain a constant temperature. Figure 7 shows a schematic diagram illustrating the power step PWR and the resulting temperature change TEMP.

[0134] In this example, the device is turned on, power transmission proceeds with power controlled by the power control loop, and then the operating point is saved (SVE 1 and 2). The operating point reflects the power transmission level of the power transmission signal relative to the current power level mode of the airflyer and can be represented by any appropriate parameter value as described above.

[0135] The values ​​are stored for both high-power level mode and low-power level mode, thereby providing the mode memory 213 with reference power levels for the two different power level modes. The power receiver can then send a mode request message MRQ when changing the power level mode, thereby allowing the power transmitter to jump directly to (or near) the new operating point by overriding the power control loop using the stored values.

[0136] Therefore, when a power level mode change is about to occur, the power receiver can notify the system of the load change and which mode to transition to. The system, specifically the power transmitter, will then know which operating point it should jump to. This reduces the risk of too much or too little power being transmitted, for example, due to delays in the control loop. This helps prevent equipment damage or reduce the risk of power loss to the power receiver, even in extreme situations.

[0137] Furthermore, the stored data can be used for future power transmissions between the power receiver and the power transmitter, as the stored values ​​can be stored and retrieved between different power transmission operations. The mode memory 213 can, in particular, store values ​​for multiple power receivers, and when a power receiver is detected for power transmission, it can proceed to use the stored set for this power receiver. If a new power receiver is detected, or if the stored data is considered invalid, for example, because it is too old, the power transmitter and power receiver can proceed to generate and store new / updated data for the power receiver.

[0138] Therefore, in the future, when a combination of power transmitter / power receiver equipment and a specific power mode is used, the operating point that was actually used can be reused. As described above, the operating value is determined during startup or initialization by the system stepwise passing through all power level modes, and the resulting operating point and reference power level are represented by any appropriate parameter, the value of which is stored as the reference power level.

[0139] For example, in the case of an air flyer, the heating element may be turned on or off, but the fan remains on at all times. During equipment startup, only the fan is initially turned on, and its operating point is measured and saved (SVE 1). Next, the heating element is turned on, and its associated operating point is measured and saved (SVE 2). Then, during operation, when the heating element should be turned on / off, the power receiver can notify that a load change is about to occur, and a mode request message MRQ for the different power mode is generated and sent to the power transmitter. The power transmitter can then immediately enter the correct operating point without any delay in the control loop. The power receiver may also be notified that the power transmitter has switched to the correct power mode by receiving a handshake in the form of a command.

[0140] In some embodiments, the power transmitter may further include a detection circuit 215 configured to detect power transmission anomalies in response to a comparison between the current power level of the drive signal and a reference power level for the current power level mode from a set of power level modes.

[0141] When operating in a specific power level mode, the power control loop can vary the power level of the power transmission signal in response to error control messages from the power receiver. However, these variations are expected to be relatively small. For example, when an air flyer is operating in a 1200W load mode, the exact power drawn will fluctuate, and the power receiver can control this so that the exact desired power for the current situation is drawn. However, this power level may change accordingly, but the fluctuation is expected to be limited under normal operating conditions, for example, the power would be expected to be in the range of 1100W to 1300W during normal operation.

[0142] Therefore, the detection circuit 215 can compare the current power level with a stored reference power level for the power level mode in which the system is currently operating. For example, the detection circuit 215 can compare the currently measured coil current I txc This can be compared with the coil current stored for the operating state of the device.

[0143] If the comparison indicates that the current power level differs significantly from the reference power level, for example, if the measured coil current differs significantly from the stored reference coil current value and a threshold, the detection circuit 215 can determine that the current operating point is not something that should be experienced during normal operation, and therefore can identify that an anomaly has been detected.

[0144] In such cases, the detection circuit 215 can, for example, notify the transmitter controller 205 that an abnormality has been detected. In response, the transmitter controller 205 can proceed to change the parameters of power transmission. For example, it can be configured to limit the power level to less than a given value, for example, the maximum coil current I txc This can be set to a level low enough to ensure that no damage occurs. In some embodiments, the maximum power level may be set to zero, specifically, power transmission may be terminated if an anomaly is detected.

[0145] It will be understood that the precise criteria used to detect anomalies based on comparisons depend on the preferences and requirements of individual embodiments, and that many different approaches and criteria are possible. It will also be understood that evaluations may include other considerations, such as conversions between different parameters. For example, if the reference power level is stored as a coil current value, but the current power level is set / measured based on the drive signal frequency, the comparison may include conversions between coil current and drive signal frequency.

[0146] It will also be understood that the actions taken in response to the detection of an anomaly may depend on the preferences and requirements of the individual embodiment. For example, in some embodiments, power transmission may be restricted or terminated. In other embodiments, the detection of an anomaly may simply result in the generation of a user warning, such as switching on a warning light. In yet another embodiment, a message may be sent to a receiver, which may take a corresponding action, such as changing the power supply to the load.

[0147] In some embodiments, the mode request message includes a timing indicator, and the mode circuit is configured to adapt the timing of setting the level of the drive signal according to this timing indicator.

[0148] Specifically, a mode request message may include an indicator of when the power receiver is about to switch to a new power level mode. For example, a mode request message may indicate that the power receiver is about to switch instantaneously to a new power level mode, in which case the power transmitter can immediately switch to the new mode by setting the power level of the power transmission signal to a corresponding reference value, for example, by setting the coil current to a stored reference value for the coil current for the new power level mode.

[0149] In other situations, the power receiver may send a mode request message indicating that a change in power level mode will occur at some point in the future, for example, in 5 seconds. In this case, the power transmitter may delay setting the power level for the indicated time, i.e., delay setting the power level to override the loop by 5 seconds.

[0150] In some embodiments, the timing indicator can indicate multiple power level mode changes. For example, a mode request message could indicate that the power receiver switches between two different modes (e.g., two power level modes for an airflyer) at a given interval (e.g., every 20 seconds), and the power transmitter can then proceed to determine when to directly set the power level in response to these switching.

[0151] In some embodiments, it will be understood that the power transmitter may send a confirmation message to the power receiver indicating that a power level has been set or will be set, and the power receiver may wait for such a confirmation message before switching between power level modes.

[0152] In some embodiments, the power transmitter may be configured to determine a reference power level based on data received from the power receiver.

[0153] In this example, the mode circuit 211 can receive information from the power receiver that enables it to calculate a reference power level. In particular, the power receiver can provide a receiver setting message that includes power receiver setting parameters. Based on the power receiver setting characteristics, the mode circuit 211 can determine a reference power level for at least one power level mode from a set of power level modes.

[0154] The power receiver setting parameters may specifically include at least one of the following: Power receiver ID; Power receiver type ID; Power receiver coil characteristics; Power receiver coil dimensional characteristics; and Power receiver coil inductance characteristics.

[0155] A power receiver ID or type ID may enable a power transmitter to retrieve data describing the characteristics of this power receiver. This data may, for example, directly provide power level modes and reference power levels for a particular receiver, as described above. However, typically, it includes power receiver characteristics that indicate the power handling of the power receiver. For example, the ID or type ID may enable a power transmitter to retrieve configuration data describing the characteristics of the power receiver coil (e.g., dimensions or inductance). Thus, the power receiver coil characteristics may be transmitted directly by the power receiver or provided indirectly by identifying the power receiver so that the power transmitter can retrieve the relevant data. In some embodiments, this data may be retrieved from an internal storage device, or in many embodiments, from an external server. For example, each manufacturer may provide a database accessible from a properly equipped power transmitter (e.g., via the Internet).

[0156] In some embodiments, setting data received from a power receiver can be used to calculate suitable values ​​for setting the parameters of the drive signal or transmitter coil signal when a power level mode change occurs. For example, it can be used to calculate the drive signal frequency, duty cycle, or coil current for different power level modes. The power level mode can be represented, for example, by a load power value indicating the power supplied to the load 503 by the power receiver, and the data received from the power receiver can be used to calculate the corresponding values ​​of the power level parameters adapted by the mode circuit 211. For example, this data may be used to calculate the coil current required to supply the indicated power to the load 503.

[0157] This data can be used, for example, to determine the power path from parameters set in a power transmitter to the load of a power receiver. Figure 8 shows an example model of the power path from the voltage of driver 201 to load 503.

[0158] In this example, the following reference numerals are used: Vin: Voltage of the drive signal from driver 201. Rp: Internal resistance of the driver and loss in the output circuit. Cp: ​​Capacitor 203 of the power transmitter resonant output circuit. Lp: Transmitter coil 103 Ls: Receiver coil 107 Cs: Capacitor in the power receiver input resonant circuit Rl: Load 503

[0159] One of the key parameters for power transmission in a wireless power transmission system is the coupling coefficient between the power transmitter coil and the power receiver coil. This depends on several factors, including the receiver coil characteristics. Therefore, the coupling coefficient between the power transmitter coil and the power receiver coil can be determined using power receiver setting data. Based on the coupling coefficient, the mode circuit 211 can determine one or more reference power levels for at least one power level mode.

[0160] For example, a power transmitter can store multiple reference power levels corresponding to a reference power receiver and nominal power level modes. However, for each power level mode, different reference power levels may be stored due to different coupling coefficients, which are important values ​​in determining the power transmitter parameters related to the power level to be extracted. Then, using the received information, the coupling coefficient for the current power receiver can be calculated, and the power transmitter can, accordingly, obtain a reference power level that matches the current coupling coefficient.

[0161] In some embodiments, the mode circuit 211 can be configured to determine a power transfer function between relevant parameters of the drive signal or transmitter coil signal and the output power from the power receiver to the load. Thus, the power transfer function can reflect the relationship between the parameters set by the mode circuit 211 and the resulting power receiver output power. This power transfer function can then be used to directly calculate reference values ​​for desired parameters from the load power from the power receiver.

[0162] The power transfer function is therefore calculated from power receiver setting data transmitted from the power receiver, and the determination of the power transfer function may specifically include determining the coupling coefficient between the power transmitter coil and the power receiver coil.

[0163] More specifically, the unknown values ​​Cs, Ls, Rs, and Rl in Figure 8 can be filled in using power receiver configuration data. Power transmitter configuration data can be used to fill in Rp, Cp, and Lp. The coupling coefficient determines the shared flux path between Ls and Lp. This can be estimated / calculated using the dimensions of the coil setup. The diameter of the coils and the distance between them can be simulated / measured to see their effect on the coupling coefficient. A function / lookup table can then be created to output the coupling coefficient for specific coil dimensions and arrangements. The coupling coefficient can also be measured by disconnecting the load on one side and supplying a voltage / current to the other side. Since the load is disconnected, no power is transmitted, but a voltage is present, which indicates the magnitude of the mutual inductance relative to the self-inductance. In all models, Kirchhoff's laws can be used to derive the transfer function from the input voltage to the output current / voltage. Based on these values, the power supplied to the load can be determined (and conversely, the drive signal parameters for a particular load can also be determined).

[0164] For clarification, the above description will be understood to have illustrated embodiments of the invention with reference to different functional circuits, units, and processors. However, it will be apparent that any appropriate distribution of functions between different functional circuits, units, or processors can be used without departing from the invention. For example, functions that are shown to be performed by separate processors or controllers may be performed by the same processor or controller. Thus, references to specific functional units or circuits should be considered only as references to appropriate means for providing the described functions, and not as indicating a strict logical or physical structure or organization.

[0165] The present invention can be implemented in any suitable form, including hardware, software, firmware, or any combination thereof. The present invention may optionally be implemented at least partially as computer software running on one or more data processors and / or digital signal processors. Elements and components of embodiments of the present invention can be implemented physically, functionally, and logically in any suitable way. In fact, functionality may be implemented in a single unit, in multiple units, or as part of other functional units. Therefore, the present invention may be implemented in a single unit, or it may be physically and functionally distributed among different units, circuits, and processors.

[0166] Although the present invention has been described in relation to several embodiments, it is not intended to be limited to any particular form described herein. Rather, the scope of the present invention is limited only by the appended claims. Furthermore, while certain features may appear to be described in relation to a particular embodiment, those skilled in the art will recognize that various features of the described embodiments can be combined in accordance with the present invention. In the claims, the term “comprises” does not preclude the existence of other elements or steps.

[0167] Furthermore, although listed individually, multiple means, elements, circuits, or method steps may be implemented, for example, by a single circuit, unit, or processor. Additionally, individual features may be included in different claims, but these may be advantageously combined in some cases, and inclusion in different claims does not mean that the combination of features is unfeasible and / or unfavorable. Also, including a feature in one category of claims does not imply limitation to that category, but rather indicates that the feature is equally applicable to other claim categories as needed. Furthermore, the order of features in a claim does not imply a specific order in which the features must operate, and in particular, the order of individual steps in a method claim does not imply that the steps must be performed in that order. Rather, the steps can be performed in any suitable order. Furthermore, a singular reference does not exclude the plural. Thus, references such as "a," "an," "first," "second," etc., do not exclude the plural. A parameter or value corresponding to another parameter or value may indicate that one parameter / value is considered / expected to result in the other parameter / value, specifically meaning that a parameter / value corresponding to a power level is a parameter / value that is considered / expected to result in a power level. The reference numerals in the claims are provided merely as clear examples and should not be construed as limiting the scope of the claims in any way.

Claims

1. A power transmitter for wirelessly supplying power to a power receiver via an electromagnetic power transmission signal, A receiver for receiving messages from the aforementioned power receiver, The output circuit has a transmitter coil for generating the power transmission signal in response to a drive signal applied to the output circuit, A drive circuit for generating the aforementioned drive signal, A power loop controller that implements a power control loop for controlling the drive signal to adjust the power level of the power transmission signal, wherein the power control loop is configured to apply a change to the power level of the power transmission signal in response to a power control error message received from the power receiver, A mode memory device configured to store a plurality of power level modes for the power receiver, wherein each power level mode is associated with at least one of a plurality of reference power levels for the power transmission signal, A mode circuit configured to adapt the drive signal to a first reference power level in response to the reception of a mode request message, wherein the first reference power level corresponds to a reference power level for a first power level mode indicated in the mode request message among a plurality of power level modes, and the mode circuit A power transmitter.

2. The power transmitter according to claim 1, further comprising a detection circuit for detecting a power transmission anomaly in accordance with a comparison between the current power level of the power transmission signal and a reference power level of the current power level mode among the plurality of power level modes.

3. The power transmitter according to claim 1 or 2, wherein the period for adapting the drive signal to set the power level of the power transmission signal to a first reference power level is less than the time constant of the power control loop.

4. The power transmitter according to any one of claims 1 to 3, wherein the mode circuit is configured to determine the reference power level for at least some of the power level modes among the plurality of power level modes with respect to at least one of the parameter values ​​of the drive signal and the parameter values ​​of the power transmission signal during an initialization phase in which the power receiver passes through the at least some power level modes step by step, and the mode memory is configured to store the reference power level for the at least some power level modes.

5. The power transmitter according to claim 4, wherein the mode memory is configured to store a plurality of parameters for at least one power level mode, the plurality of parameters including at least one reference power level representing the power level of the power transmission signal, and at least one parameter value for at least one of the drive signal and the transmitter coil signal, the at least one parameter value being at least one value of the drive signal and the transmitter coil signal relative to the power level of the power transmission signal indicated by the reference power level.

6. The power transmitter according to claim 4, wherein the initialization phase precedes the power transmission phase.

7. The power transmitter according to any one of claims 1 to 6, wherein the receiver is configured to receive a power receiver setting message from the power receiver, the power receiver setting message having a power receiver setting parameter, and the mode circuit is configured to determine the reference power level for at least one of the plurality of power level modes in accordance with the power receiver setting parameter.

8. The aforementioned power receiver setting parameters are Power receiver ID, Power receiver type ID, Power receiver coil characteristics, Power receiver coil dimensional characteristics, Power receiver coil inductance characteristics, The power transmitter according to claim 7, having at least one of the following.

9. The power transmitter according to claim 7 or 8, wherein the mode circuit is configured to determine a coupling coefficient between the transmitter coil and the power receiver coil of the power receiver based on the power receiver setting parameters, and to determine the reference power level for the at least one power level mode based on the coupling coefficient.

10. The power transmitter according to any one of claims 7 to 9, wherein the mode circuit is configured to determine a power transfer function between at least one of the drive signal parameters and transmitter coil signal parameters and the output power of the power receiver based on the power receiver setting parameters, and to determine the reference power level for the at least one power level mode based on the power transfer function.

11. The power transmitter according to any one of claims 1 to 10, wherein the mode memory is configured to store a set of power level modes for different power receivers, and the mode circuit is configured to select the set of power level modes in accordance with an ID index received from the power receiver.

12. The power transmitter according to any one of claims 1 to 11, wherein the mode request message has a timing indicator, and the mode circuit is configured to adapt the timing for setting the power level of the power transmission signal according to the timing indicator.

13. The power transmitter according to any one of claims 1 to 12, wherein the mode request message is received during the power transmission phase.

14. A method for operating a power transmitter for wirelessly supplying power to a power receiver via an electromagnetic power transmission signal, wherein the power transmitter has an output circuit having a transmitter coil for generating the power transmission signal in response to a drive signal applied to the output circuit, and the method is The steps include receiving a message from the power receiver, The steps of generating the aforementioned drive signal, A step of operating a power control loop that controls the drive signal in order to adjust the power level of the power transmission signal, wherein the power control loop is configured to apply a change to the power level of the power transmission signal in response to a power control error message received from the power receiver, A step of storing a plurality of power level modes for the power receiver in a mode memory device, wherein each power level mode is associated with at least one of a plurality of reference power levels for the power transmission signal. Steps of adapting the drive signal to set the operating point of the power level of the power transmission signal to a first reference power level in response to the reception of a mode request message, wherein the first reference power level corresponds to a reference power level for a first power level mode indicated in the mode request message among a plurality of power level modes; A method of having.

15. A wireless power transmission system having a power transmitter for wirelessly supplying power to a power receiver via an electromagnetic power transmission signal, wherein the power transmitter is A receiver for receiving messages from the aforementioned power receiver, The output circuit has a transmitter coil for generating the power transmission signal in response to a drive signal applied to the output circuit, A drive circuit for generating the aforementioned drive signal, A power loop controller that implements a power control loop for controlling the drive signal to adjust the power level of the power transmission signal, wherein the power control loop is configured to apply a change to the power level of the power transmission signal in response to a power control error message received from the power receiver, A mode memory device configured to store a plurality of power level modes for the power receiver, wherein each power level mode is associated with at least one of a plurality of reference power levels for the power transmission signal, A mode circuit configured to adapt the drive signal to a first reference power level in response to the reception of a mode request message, wherein the first reference power level corresponds to a reference power level for a first power level mode indicated in the mode request message among a plurality of power level modes, and the mode circuit A wireless power transmission system having

Images