Dynamic Control of Wireless Power for Variable Loads

Abstract

The present disclosure provides a system, method, and device for wireless power transmission and reception. A wireless power transmitting device can include a primary coil that transmits power to a corresponding secondary coil in a wireless power receiving device. The wireless power receiving device can include a variable load. The wireless power transmitting device can control the transmission of wireless power based on configuration data and feedback information from the wireless power receiving device. The configuration data and feedback information can enable dynamic control of the wireless power and can enable the wireless power transmitting device to determine appropriate operational control parameters for the transmission of wireless power to support the load conditions of the variable load at a particular time. In some implementations, the wireless power transmitting device can take into account an operational coupling coefficient (K-factor) or other information to estimate the control parameters.

Description

[Technical field]

[0001] The present disclosure relates generally to wireless power. More specifically, the present application relates to wireless power transmitting and receiving devices. [Background technology]

[0002] Some wireless power systems utilize wireless power technology to wirelessly supply power to cordless appliances with variable loads, such as certain blenders, kettles, air fryers, mixers, etc. In these wireless power systems, a wireless power transmitting device may be placed on or included in a countertop or other flat surface. A wireless power receiving device may be included in the cordless appliance. The wireless power transmitting device may include a primary coil that generates an electromagnetic field that can induce a voltage in the secondary coil of the wireless power receiving device when the secondary coil is placed in close proximity to the primary coil. In this configuration, the electromagnetic field can wirelessly transmit power to the secondary coil. The power may be transferred using inductive or resonant coupling between the primary and secondary coils. The wireless power receiving device can provide the received power to operate the cordless appliance. Summary of the Invention

[0003] The systems, methods, and devices of the present disclosure each have several innovative aspects, no single one of which alone will result in the desirable attributes disclosed herein.

[0004] One innovative aspect of the subject matter described in this disclosure can be implemented as a method for wirelessly transmitting power. The method may be performed by a wireless power transmitting device. In some implementations, the method can include obtaining configuration data, a load state, and a reference voltage associated with a variable load of the wireless power receiving device. The method can include initiating a transmission of wireless power to the wireless power receiving device using an operational control parameter based on the configuration data, the load state, and the reference voltage. The method can include receiving feedback information from the wireless power receiving device during the transmission of wireless power. The feedback information can include a load voltage measured by the wireless power receiving device and can further indicate a change in the load state, the reference voltage, or both. The method can include modifying the operational control parameter based on the feedback information.

[0005] Another innovative aspect of the subject matter described in this disclosure can be implemented as a method for wirelessly receiving power. The method can be performed by a wireless power receiving device. In some implementations, the method can include transmitting configuration data, a load state, and a reference voltage associated with a variable load of the wireless power receiving device to a wireless power transmitting device. The method can include receiving wireless power from the wireless power transmitting device based on the configuration data, the load state, and the reference voltage. The method can include transmitting feedback information to the wireless power transmitting device during reception of the wireless power. The feedback information can include a load voltage measured by the wireless power receiving device and can further indicate a change in the load state, the reference voltage, or both.

[0006] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the specification, drawings, and claims. Please note that the relative dimensions of the following figures may not be drawn to scale. [Brief description of the drawings]

[0007] [Figure 1] 1 shows a block diagram of an example wireless power system including an example wireless power transmitting device and an example wireless power receiving device. [Figure 2A] 1 illustrates a perspective view of an exemplary countertop-mounted wireless power transmission device. [Figure 2B] 1 illustrates a perspective view of an exemplary countertop mounted wireless transmission device and an exemplary cordless appliance. [Diagram 3] 1 shows a block diagram conceptually illustrating an exemplary wireless power transmission device. [Figure 4A] 1 shows a block diagram conceptually illustrating components of an example transmission controller using voltage control. [Figure 4B] 1 shows a block diagram conceptually illustrating components of an example transmission controller employing power control. [Diagram 5] 1 shows a block diagram conceptually illustrating an example format of feedback information. [Figure 6] 1 shows a block diagram conceptually illustrating an exemplary wireless power receiving device. [Figure 7] 1 illustrates an exemplary voltage curve that enables timing synchronization of operations between a wireless power transmitting device and a wireless power receiving device. [Figure 8] 1 illustrates an example voltage curve that allows a transmission controller of a wireless power transmitting device to be synchronized with a load controller of a wireless power receiving device. [Figure 9] 1 shows an example voltage graph for a wireless power system implementing traditional feedback control techniques. [Figure 10] 1 illustrates an example voltage graph for a wireless power system implementing power control according to some implementations of the present disclosure. [Figure 11] 1 shows a flow diagram illustrating an example operation of a process for providing wireless power to a wireless powered device. [Figure 12] 1 shows a flow diagram illustrating an example operation of a process for receiving wireless power in a wireless power receiving device. [Figure 13]1 shows a flow diagram illustrating an example operation of a process in an example wireless powered device having a motor with section windings. [Figure 14] 14 shows a flow diagram illustrating an example operation of a process in an example wireless power transmitting device for transmitting wireless power corresponding to the process described with reference to FIG. 13. [Figure 15] 15 shows a block diagram illustrating the power control operation of an exemplary wireless power transmitting device corresponding to the process described with reference to FIG. 14. [Figure 16] 1 shows a flow diagram illustrating an example operation of a process in an example wireless powered device associated with an air fryer. [Figure 17] 17 shows a flow diagram illustrating an example operation of a process in an example wireless power transmitting device for transmitting wireless power corresponding to the process described with reference to FIG. 16. [Figure 18] 18 shows a block diagram illustrating the power control operation of an exemplary wireless power transmitting device corresponding to the process described with reference to FIG. 17. [Figure 19] 1 shows a block diagram of an exemplary apparatus for use in a wireless power system.

[0008] Please note that the relative dimensions of the figures may not be drawn to scale. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The following description refers to specific implementations for purposes of illustrating the innovative aspects of the present disclosure. However, those skilled in the art will readily recognize that the teachings herein can be applied in many different ways. The described implementations can be implemented in any means, device, system, or method for transmitting or receiving wireless power.

[0010] A wireless power system may include a wireless power transmitting device integrated into or otherwise disposed on a surface. Additionally, a wireless power system may include a wireless power receiving device. The wireless power transmitting device may include a primary coil that transmits power (as a wireless power signal) to a corresponding secondary coil in the wireless power receiving device. For example, the wireless power transmitting device may include a primary coil mounted on a countertop or embedded or fabricated in a surface on which the wireless power receiving device may rest. The primary coil refers to the source of wireless energy (such as induction or magnetic resonance energy) in a wireless power transmitting device. A secondary coil disposed in the wireless power receiving device may receive the wireless energy and utilize it to charge or operate a load. The wireless power receiving device may be included in or integrated with a cordless appliance having a variable load (such as a blender, a heating element, a fan, among other examples).

[0011] The present disclosure provides systems, methods, and devices for wireless power transmission and reception. Various implementations generally relate to dynamic control of wireless power transmission from a wireless power transmitting device to a wireless power receiving device. The dynamic control of wireless power can be based on a load condition associated with a variable load of the wireless power receiving device. The wireless power receiving device can communicate configuration data and feedback information to the wireless power transmitting device to determine operational control parameters for wireless power transmission. For example, the operational control parameters can include an operating frequency, a duty cycle, or a voltage such that a primary coil of the wireless power transmitting device induces an appropriate amount of power to support the load condition of the variable load. In some implementations, the wireless power receiving device can communicate the configuration data, the load condition, a reference voltage, or any combination thereof such that a transmit (TX) controller of the wireless power transmitting device can determine an estimated operational parameter specific to the wireless power receiving device. The wireless power transmitting device can determine the operational control parameter based on the estimated operational parameter. During the transmission of wireless power, the wireless power receiving device can communicate feedback information indicative of changes in load conditions, measured load voltages, reference voltages, or any combination thereof to cause the wireless power transmitting device to adjust operational control parameters. In some implementations, the wireless power transmitting device can also take into account a coupling factor (K-factor) in estimating or adjusting the operational control parameters. In some implementations, changes in wireless power transmission can be made at synchronous events such that the changes in wireless power transmission occur in relation to corresponding changes in load conditions.

[0012] In some implementations, the configuration data can include start-up control parameters (such as a start-up frequency (Fstart), among other examples). The configuration data can indicate control parameter limits (such as a frequency limit (Flimit), among other examples). The TX controller can determine operational control parameters based on the start-up control parameters and the control parameter limits. During the transmission of wireless power, the TX controller can adjust the operational control parameters based on the feedback information. For example, the feedback information can indicate a measured load voltage and a reference voltage. The measured load voltage indicates the voltage being delivered to the variable load. The reference voltage indicates the voltage required to operate the variable load at the current load setting. The TX controller can determine a voltage error and adjust the operational control parameters based on the load voltage and the reference voltage. In some implementations, the TX controller can also change the estimated operational parameters based on changes in load conditions.

[0013] In some implementations, the configuration data may include one or more reference control parameters associated with one or more reference load conditions. For example, the reference control parameters may be based on data obtained experimentally when powering a wireless power receiving device by a reference wireless power transmitting device at various load conditions. In some implementations, the configuration data may also indicate a type of reference wireless power transmitting device. The TX controller may determine an estimated operating parameter based on a load condition of the wireless power receiving device compared to a particular reference load condition in the configuration data and select the estimated operating parameter based on the reference control parameter associated with the reference load condition. In some implementations, the configuration data may include two or more reference control parameters associated with a particular reference load condition. For example, the configuration data may indicate a reference control parameter associated with various reference K-factors for a particular reference load condition. The TX controller may determine an operating K-factor between the wireless power transmitting device and the wireless power receiving device and select a reference control parameter that matches the reference K-value. In some implementations, the TX controller may determine an estimated operating parameter based on an interpolation of two or more reference control parameters when the operating K-factor is between two or more corresponding reference K-factors. The operational K factor refers to a K factor based on the actual alignment between the wireless power receiving device and the wireless power transmitting device currently providing wireless power. The reference K factor can represent data points under various reference operating conditions, and the operational K factor can be interpolated or extrapolated even if it is not exactly the same as the reference K factor. The transmission controller can then use this information to determine one or more operational control parameters to be used to provide wireless power with specific characteristics, such as a specific frequency, duty cycle, voltage, etc. By using this information to determine characteristics of the wireless power to be transmitted to the wireless power receiving device, the transmission controller can also provide wireless power that allows for relatively efficient operation of the wireless power receiving device. For example, the transmission controller can set the wireless power to allow the wireless power receiving device to operate at peak efficiency for a particular load condition, load voltage, and operational K factor.

[0014] In some implementations, the power transmission controller can respond to changes in load conditions by synchronously adjusting power modifications with the wireless powered device. The load state can indicate that a user has selected a different speed setting for a motor load, selected a different temperature setting for a resistive load, or otherwise changed a load state of the cordless device selectable by the user. The load state can also indicate the state of two or more variable loads in the cordless device. For example, an air fryer can include a heating element and a fan, each of which has variable power requirements based on a load setting or programmed operation. The load state can indicate, for example, whether the heating element, the fan, or both are currently operating. If the load state changes with respect to a variable load associated with the wireless powered device, the power transmission controller may need to modify the wireless power to accommodate the new load state. The power transmission controller can modify the frequency, duty cycle, voltage, or any other suitable characteristic of the wireless power. The power transmission controller can synchronously coordinate with the wireless powered device such that the transmission of modified wireless power by the power transmission controller begins substantially simultaneously with the initiation of consumption of modified wireless power by the wireless powered device. Such synchronous coordination allows the power requirements of the wireless powered devices to be met without delay. By avoiding these delays, the power transmission controller can enable the wireless powered devices to respond more quickly to changing load conditions and avoid fault conditions that could damage the cordless device and degrade the user experience.

[0015] In some implementations, the power transmission controller can modify one or more operational control parameters used to supply wireless power based on feedback information received from the wireless power receiving device. The feedback information can indicate a change in load condition, a change in a reference voltage, or a fault condition, among other examples. The feedback information can be included in one or more feedback messages communicated by the wireless power receiving device to the wireless power transmitting device. In some implementations, the feedback message can be formatted to include a load condition field, a measured load voltage field, and one or more data fields. A header in the feedback message can indicate the type of data in the one or more data fields. In some implementations, the feedback message can include a checksum field to ensure that the data is delivered reliably. The feedback messages can be communicated in feedback slots that occur at regular intervals relative to a zero-crossing event corresponding to an AC power supply voltage.

[0016] Moreover, various implementations generally relate to a wireless power receiving device that includes a secondary coil that receives power from a corresponding primary coil of a wireless power transmitting device. In some implementations, a load controller of the wireless power receiving device can synchronize and coordinate changes in power with the wireless power transmitting device. As already mentioned, a load condition can change with respect to a load of a variable load associated with the wireless power receiving device. In response to the change in load condition, the load controller can inform the wireless power transmitting device of the load condition. Instead of immediately drawing a modified amount of power from the wireless power transmitting device, the load controller can wait for a synchronization event before drawing the modified amount of power from the wireless power transmitting device. By waiting for a synchronization event, the load controller can coordinate with the wireless power transmitting device to draw the modified power approximately simultaneously with the transmission of the modified power by the wireless power transmitting device.

[0017] The techniques of the present disclosure may enable a wireless power transmitting device to estimate operational control parameters faster than a wireless power transmitting device that does not implement the techniques of the present disclosure. For example, traditional feedback techniques designed to modify power after detecting a change in load. Thus, traditional feedback techniques may cause delays between the time when a load condition is changed and the time when wireless power can be supplied to accommodate the new load condition. Wireless power delays may cause fault conditions that may damage the cordless device and degrade the user experience. Using the techniques of the present disclosure, a wireless power transmitting device may estimate operational control parameters for a particular load condition of a wireless power receiving device before the load is actually changed. The wireless power transmitting device and the wireless power receiving device may coordinate wireless power transmission and load changes, respectively, such that power is available when needed to operate the load in the load condition.

[0018] Particular implementations of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages: In some implementations, the described techniques can be used to configure a wireless power transmitting device to provide wireless power at the appropriate time with characteristics (e.g., a particular frequency, duty cycle, voltage, etc.) that enable operation at the relative efficiency of the wireless power receiving device. In some implementations, the described techniques can be used to achieve synchronous coordination between the wireless power transmitting device and the wireless power receiving device when responding to changes in load conditions. These techniques can avoid delays associated with traditional feedback mechanisms designed to facilitate power modifications. Additionally, these techniques can improve the user experience by increasing responsiveness to changes in load conditions.

[0019] Although the examples in this disclosure are based on wireless power used in kitchen systems, the technology is also applicable to other types of systems. For example, the technology may be used in wireless power systems associated with home appliances, electronic devices, fans, space heaters, speaker systems, air compressors, gardening equipment, or components of electric vehicles, among other examples. Furthermore, some examples of the present disclosure are based on voltage control, where the operating frequency or other parameters can be controlled based on voltage control feedback information. However, the technology is also applicable to power control, where the operating parameters can be controlled based on power control feedback information.

[0020] 1 shows a block diagram of an example wireless power system including an example wireless power transmitting device and an example wireless power receiving device. In FIG. 1, dashed lines represent communication, as distinguished from solid lines representing electrical circuit lines.

[0021] The wireless power system 100 comprises a wireless power transmitting device 102 and a wireless power receiving device 118. The wireless power transmitting device includes a primary coil 104. The primary coil 104 may be associated with a power signal generator 106. The primary coil 104 may be a wire coil that transmits wireless power (sometimes referred to as wireless energy). The primary coil 104 may transmit the wireless energy using an induction field or a magnetic resonance field. The power signal generator 106 may include components (not shown) for creating the wireless power. For example, the power signal generator 106 may include one or more switches, drivers, series capacitors, rectifiers, or other components.

[0022] In some implementations, the power signal generator 106, the TX controller 108, and other components (not shown) can be collectively referred to as a power transmitting circuit 110. Some or all of the power transmitting circuit 110 may be embodied as an integrated circuit (IC) that implements features of the present disclosure for controlling and transmitting wireless power to one or more wireless power receiving devices. The TX controller 108 may be realized as a microcontroller, a special purpose processor, an integrated circuit, an application specific integrated circuit (ASIC), or any other suitable electronic device.

[0023] A power source 112 can provide power to the power transmission circuitry 110 in the wireless power transmitting device 102. The power source 112 can convert alternating current (AC) power to direct current (DC) power. For example, the power source 112 can include a converter that receives AC power from an external power source and converts the AC power to DC power used by the power signal generator 106.

[0024] The TX controller 108 is connected to a first communication interface 114. The first communication interface 114 is connected to a first communication coil 116. In some implementations, the first communication interface 114 and the first communication coil 116 can be collectively referred to as a first communication unit 124. In some implementations, the first communication unit 124 can support Near Field Communication (NFC). NFC is a technology that transmits data at a carrier frequency of 13.56 megahertz (MHz). Furthermore, the first communication unit 124 can support any suitable communication protocol.

[0025] The wireless power receiving device 118 may include a secondary coil 120, a rectifier 126, a power receiving (RX) controller 128, a second communication interface 132, a load controller 136, a load 130, and a memory (not shown). In some implementations, the load 130 may further include a drive (not shown) for controlling at least one parameter, such as the speed or torque, of the load. In some implementations, the rectifier 126 may be omitted. In some implementations, a series switch (not shown) may be included in series with the secondary coil 120. Although shown as different components, some components may be packaged or implemented in the same hardware. For example, in some implementations, the RX controller 128 and the load controller 136 may be implemented as a single controller. The RX controller 128, the load controller 136, or any combination thereof may be implemented as a microcontroller, a dedicated processor, an integrated circuit, an application specific integrated circuit (ASIC), or any other suitable electronic device.

[0026] The TX controller 108 can detect the presence or proximity of the wireless power receiving device 118. This detection can occur during a periodic ping process of the first communication interface 114 of the wireless power transmitting device 102. During the ping process, the first communication interface 114 can also provide power (via the first communication coil 116) to the second communication interface 132 (via the second communication coil 134) if the wireless power receiving device 118 is in proximity. The second communication interface 132 can "wake up" and activate the RX controller 128 and send a response signal back to the first communication interface 114. Prior to the power transfer, a handshake process can take place. During the handshake process, the TX controller 108 can receive a data configuration related to, among other things, the power rating of the receiver.

[0027] Different cordless appliances may have different load types, different load states, and different power requirements, or may require power at specific voltages and frequencies. For example, a cordless blender may include a variable motor load with multiple user-selectable load states to control the motor speed. Depending on the load state, the cordless blender may require different levels of power to operate. In another example, a cordless kettle may include a resistive load with different load states to control the temperature. In yet another example, an air fryer may be a multi-load device and may operate a heater, a fan, or both at various operating periods. Each type of load (motor, resistive load, heater, fan, or any combination thereof, etc.) may require different amounts of power to operate based on the current load state or load conditions. Additionally, cordless appliances may have different levels of voltage gain from the primary coil to the powered coil at different primary coil excitation frequencies (e.g., wireless power transmission frequencies) depending on their load types or load conditions. For example, to achieve a desired load voltage, a cordless blender may operate best at a first operating frequency for a first load state, such as a low motor speed setting. However, as load conditions change, the cordless blender may not be able to achieve the same load voltage when operated at the first operating frequency. For example, the first operating frequency may facilitate a first voltage gain when the cordless blender is set to a first load condition (such as a low speed setting), but the first operating frequency may only provide a lower voltage gain when the cordless blender is set to a second setting (such as a high speed setting).

[0028] In some implementations, the cordless device can have user-selectable load states or user-selectable load operation patterns. The user can select a first load state to activate the cordless device. When the cordless device is operating in the first load state, the user can select a second load state that requires more or less power. Without the techniques in this disclosure, the wireless power receiving device may immediately begin to consume different amounts of power in response to a change in load state. However, there may be some delay before the wireless power transmitting device can provide the amount of power required by the wireless power receiving device. These delays may cause undervoltage conditions, overvoltage conditions, hardware damage or failure, and other failures in the cordless device.

[0029] Another factor that may change the voltage gain is based on the alignment of the secondary coil 120 and the primary coil 104 during power transfer. The voltage gain may be measured in terms of the ratio of the voltage received by the secondary coil 120 to the voltage applied at the primary coil 104. A coupling factor, called the K-factor, may be an indication of the alignment and may be calculated in a K-factor determination process based on the ratio of the voltage applied to the primary coil 104 and the voltage measured at the secondary coil 120. The K-factor determination process may be performed when no current is flowing through the secondary coil 120. For example, the K-factor determination process may be performed such that the application of a voltage to the primary coil 104 and the measurement of the corresponding received voltage at the secondary coil 120 are performed during a zero-crossing event of the AC source voltage. In some implementations, a switch (not shown) may decouple the secondary coil 120 from the rectifier 126 during the K-factor determination process. The K-factor determination process may be performed periodically in a time slot associated with the zero-crossing event. In some implementations, the number of turns in the primary coil 104 and the secondary coil 120 may affect the calculation of the K-factor. For example, the K factor may be calculated based on the multiplication of a first operand and a second operand, where the first operand is the voltage measured at the secondary coil 120 divided by the number of coil turns in the secondary coil 120, and the second operand is the number of coil turns in the primary coil 104 divided by the voltage applied to the primary coil 104.

[0030] The operating K factor represents the current alignment of the primary coil 104 and the secondary coil 120. The wireless powered device 118 may experience different voltage gains at different operating frequencies at different K factors. The reference K factor and reference operating frequency may be determined based on laboratory testing when the wireless powered device 118 is operating at a reference wireless power transmitting device (not shown) under a reference load condition. The reference load condition, reference operating frequency, and reference K factor may represent data points that the TX controller 108 may use to determine estimated operating parameters when it receives a message from the wireless powered device 118 indicating the load condition of the load 130.

[0031] Wireless power transmission is more efficient when the primary and secondary coils are optimally aligned. Conversely, efficiency may decrease (or power transmission may cease) if the primary and secondary coils are misaligned. When properly aligned, the primary and secondary coils can transmit wireless energy up to an amount predetermined by the wireless standard. For example, with proper alignment, the primary coil can transmit power ranging from 30 watts (W) to 2.2 kilowatts (KW). Because alignment affects the efficiency of power transmission, the wireless power transmitting device can modify the amount of wireless power based on the alignment with the wireless power receiving device.

[0032] The TX controller 108 can control characteristics of the wireless power it provides to the wireless powered device 118. After detecting the wireless powered device 118, the TX controller 108 can receive configuration data from the wireless powered device 118. For example, the TX controller 108 can receive the configuration data during a handshake process with the wireless powered device 118. Among other examples, the configuration data can indicate one or more reference control parameters such as the operating frequency of the wireless powered device 118 at different reference K factors, the load condition, the load voltage and the load power of the wireless powered device 118 when operating on a reference wireless power transmitting device. In some implementations, the configuration data can include estimator data (e.g., interpolation points, vector values, etc.) that allows the TX controller 108 to adjust the locally stored information to suit various conditions and settings such that the TX controller 108 can provide power that enables relatively efficient operation of the wireless powered device 118. In some implementations, the wireless powered device 118 can provide an empirical formula for calculating one or more reference control parameters as a function of the reference K factor, the load voltage, and the load power. The TX controller 108 can use the configuration data to determine at least one estimated operating parameter (e.g., frequency, duty cycle, voltage, etc.) for the wireless power it provides to the wireless powered device 118. The TX controller 108 can initially set the operating control parameters based on the estimated operating parameters. The operating control parameters, the estimated operating parameters, or both can be adjusted based on feedback information from the wireless powered device 118 during the transmission of wireless power in response to changes in the load condition or power requirements of the load 130. Thus, the TX controller 108 can provide wireless power that enables relatively efficient operation of the wireless powered device 118. For example, the transmission controller can set the wireless power to enable the wireless powered device to operate at peak efficiency for a particular load condition, load voltage, and operating K-factor.

[0033] The format of the configuration data provided by the wireless power receiving device 118 may vary in different implementations. For example, the configuration data may include estimator data indicative of one or more reference control parameters, such as an operating frequency, associated with one or more reference K-factors between the wireless power receiving device and a reference wireless power transmitting device at one or more load conditions of the wireless power receiving device obtained during testing of the wireless power receiving device 118 on a reference wireless power transmitting device. The load conditions are representations reflecting a combined state of the load voltage and corresponding load power setting of the wireless power receiving device 118. The configuration data may include an indication of the type of reference wireless power transmitting device used for the test.

[0034] In another form, the configuration data can include start-up control parameters instead of or in addition to the estimator data. For example, the start-up control parameters can indicate a start-up frequency (Fstart), a duty cycle, a start-up voltage, or other parameters. In some implementations, the configuration data can include a control parameter limit. The control parameter limit can indicate a frequency limit (Flimit). The TX controller 108 can determine an estimated operating parameter or adjust the operating control parameter such that the resulting operating control parameter does not fall below Flimit.

[0035] An example format for the configuration data is shown in Table 1. The example in Table 1 is provided for educational purposes only, and some formats or fields may be added or omitted. [Table 1]

[0036] If the configuration data includes estimator data (Est_data_size≠0), the configuration data may also include entries for the estimator data. Est_data_size may indicate the number of entries or may indicate the total byte length of the estimator data. Table 2 shows an example format of an estimator data entry. [Table 2]

[0037] Some types of wireless powered devices 118 may have more load conditions than other wireless powered devices. For example, if the wireless powered device 118 is a blender with only one speed setting or a blender with section windings, the estimator data may include only one reference load condition. In some implementations, the values ​​in the estimator data may be normalized to reduce overhead. For example, the reference K factor may be normalized on a scale of 32 (2^5). The Kmax (0.7 or 70%) and Kmin (0, 2 or 20%) data may be the minimum required reference K factor. Estimator data for other reference K values ​​may be provided. In some implementations, the reference K factor may be omitted in the estimator data entry.

[0038] In addition to the configuration data, the wireless powered device 118 may also provide a load status indicating a current or expected load status of the load 130. In some implementations, the wireless powered device 118 may provide a reference voltage (or requested power). The TX controller 108 may determine the estimated operating parameters by matching the load status with the reference load status in one or more of the entries in the estimator data. If the estimator data includes two or more entries with the same reference load status, the TX controller 108 may select either entry based on the operating K factor and the reference K factor, or may interpolate between the two entries. In this manner, the TX controller 108 may determine the reference operating parameters to use in estimating the estimated operating parameters. If the estimator data is not included in the configuration data, the TX controller 108 may use the start-up control parameters as the reference operating parameters. The TX controller 108 may determine the estimated operating parameters based on the reference operating parameters and the reference voltage.

[0039] The TX controller 108 can respond to changes in load conditions by synchronously coordinating power modifications with the wireless powered device 118. The load conditions can indicate that a user has selected a different speed setting for a motor load, selected a different temperature setting for a resistive load, or otherwise modified any suitable setting of the cordless device. The load condition changes can be initiated by the device without user intervention to achieve a desired performance. For example, the device controller can turn a heater on and off without user intervention to regulate the temperature. If the load conditions change with respect to a variable load associated with the wireless powered device, the TX controller 108 may need to modify the wireless power to accommodate the change. The TX controller 108 can modify the frequency, duty cycle, voltage, or any other suitable characteristic of the wireless power. The TX controller 108 can synchronously coordinate with the wireless powered device 118 such that the transmission of modified wireless power by the TX controller 108 begins substantially simultaneously with the initiation of consumption of modified wireless power by the wireless powered device 118. Such synchronous coordination allows the power requirements of the wireless powered device 118 to be met without delay. By avoiding these delays, the TX controller 108 can enable the wireless powered device to avoid fault conditions that could damage the cordless device or degrade the user experience. In some implementations, the TX controller 108 can modify the wireless power based on information received from the wireless powered device. The information can include load conditions, estimated power required by the variable load, voltage information for determining an operational K factor, and a reference voltage indicative of the voltage required by the variable load. The TX controller 108 can use some or all of this information to determine operational control parameters for modifying the wireless power. In some implementations, the TX controller 108 can initiate transmission of the modified wireless power in response to any suitable synchronization event, such as when the AC power supplied to the wireless power transmitting device 102 crosses 0 volts.

[0040] In some implementations, the wireless power receiving device 118 may be included in a cordless appliance, such as a cordless blender, a cordless kettle, a cordless juicer, etc. The wireless power receiving device 118 may include a secondary coil 120, a rectifier 126, and an RX controller 128. When the secondary coil 120 is aligned with the primary coil 104, the secondary coil 120 may generate an induced voltage based on the wireless power signal received from the primary coil 104. A capacitor may be in series between the secondary coil 120 and the rectifier 126. The rectifier 126 may rectify the induced voltage and provide the induced voltage to a load 130. The load 130 may be any suitable load, such as a variable motor load, a variable resistive load, or a variable induction heating load. The load may include an additional electronic driver (not shown).

[0041] The RX controller 128 may be operatively coupled to the rectifier 126 and the second communication interface 132. The second communication interface 132 may include modulation and demodulation circuitry for wireless communication via the second communication coil 134. Thus, the RX controller 128 may wirelessly communicate with the feedback controller 122 via the second communication interface 123 to the first communication interface 114 using NFC communication. Alternatively or additionally, the RX controller 128 may use load modulation to communicate via an in-band communication link (not shown) including the secondary coil 120.

[0042] The load controller 136 may be operatively coupled to the load 130 and the second communication interface 132. The load controller 136 may detect changes in load conditions. For example, the load controller 136 may detect changes in user-selectable load conditions, such as a temperature selector and a motor speed selector. Additionally, the load controller 136 may determine a load voltage reference and a load condition based on the power estimate. Additionally, the load controller 136 may provide the load condition, the load voltage reference, and any other suitable information to the RX controller 128 or the second communication interface 132 for communication with the wireless power transmitting device 102. Additionally, the RX controller 128 may determine and provide feedback information indicative of a measured load voltage available to the load 130. In some feedback messages, the feedback information may include a reference voltage indicative of a voltage required for the load 130. In some feedback messages, the feedback information may include a coil voltage measured at the secondary coil 120 as part of a K-factor determination process. Although the RX controller 128 and the load controller 136 are shown separately, they may be included in the same component of the wireless power receiving device 118.

[0043] In some implementations, the load controller 136 can synchronously coordinate the change in wireless power with the wireless power transmitting device 102. For some motor loads, the load controller 136 can also control additional hardware (such as switches and drives) (not shown in FIG. 1 ) associated with the load. In some implementations, these additional switches can be turned on or off to effect the change in load in synchronization with the change in wireless power transmission. As already mentioned, the load condition can change for the load 130. In response to the change in the load condition, the load controller 136 can notify the wireless power transmitting device 102 of the change in the load condition. Instead of immediately drawing an amount of power commensurate with the load condition, the load controller 136 can wait for a synchronization event before setting the load 130 to draw a modified amount of wireless power. By waiting for a synchronization event, the load controller 136 can coordinate with the wireless power transmitting device 102 to begin consuming the modified wireless power substantially simultaneously with the start of the generation of the modified power in the wireless power transmitting device. The synchronization event may be any suitable event, such as when the average direct current (DC) voltage after the rectifier 126 (based on the line frequency of the AC power source powering the wireless power transmitting device) approaches a minimum value (e.g., 0 volts). In another example, the synchronization event may correspond to the point in time when the AC power source voltage powering the wireless power transmitting device crosses 0 volts.

[0044] In some implementations, the techniques for determining the wireless power operational control parameters may be performed from the beginning of the initiation of wireless power transfer to the wireless power receiving device 118, such as during an initialization phase of the wireless power transfer. In some implementations, the techniques may be used to determine new operational control parameters in response to feedback information indicative of changes in load conditions, reference voltages, or operational K-factors.

[0045] 2A illustrates a perspective view 200 of a wireless power transmitting device mounted on an exemplary countertop. In some implementations, the wireless power transmitting device may be coupled to or integrated with the countertop 202. For example, a primary coil 204 of the wireless power transmitting device may be flush embedded into the countertop 202. For simplicity, only the primary coil 204 of the wireless power transmitting device is shown in FIG. 2A. However, other components of the wireless power transmitting device, such as those described with reference to FIG. 1, may be integrated into or attached to the countertop 202.

[0046] 2B illustrates a perspective view 200 of an exemplary countertop mounted wireless transmitting device and an exemplary cordless device. The cordless device (shown as a blender 206) can be placed over the primary coil 204. The cordless device can include a load setting 208 that can be selected by a user. The cordless device can include a wireless power receiving device (not shown in FIG. 2B). The wireless power transmitting device and the wireless power receiving device can include any of the components and functions described herein.

[0047] FIG. 3 shows a block diagram conceptually illustrating an exemplary wireless power transmitting device. In FIG. 3, the wireless power transmitting device 300 may include a power source 302, which is shown as an AC power source. However, the power source 302 may be a DC power source or any other suitable power source. The power source 302 may be connected to a rectifier 304, which may be connected to a capacitor 306. Furthermore, the power source 302 may be connected to a synchronization unit 308. The synchronization unit 308 may generate a synchronization signal based on the AC power from the power source 302. The synchronization unit 308 may provide the synchronization signal to the TX controller 108. If the power source 302 is a DC power source, the synchronization unit may generate a signal autonomously at regular intervals.

[0048] The rectifier 304 may provide DC power to a first switch 316 and a second switch 318. The first switch 316 and the second switch 318 may be metal oxide semiconductor field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs), among other examples. A first pulse width modulation (PWM) driver 312 may be connected to the first switch 316, and a second PWM driver 314 may be connected to the second switch 318. The TX controller 108 may be connected to the first PWM driver 312 and the second PWM driver 314.

[0049] The TX controller 108 can exchange communications with the wireless powered device via a communication interface 326. The communication interface 326 may include a communication controller (not shown) coupled to a communication coil 328. In some implementations, the communication interface 326 and the communication coil 328 are configured to communicate using an NFC communication protocol.

[0050] The wireless power transmitting device 300 can provide wireless power to the wireless power receiving device. The TX controller 108 can detect the wireless power receiving device in proximity to the primary coil 322 and perform a handshake process in which the TX controller 108 receives information from the wireless power receiving device. The TX controller 108 can receive this information via the communication interface 326. The information can include one or more reference control parameters, such as the operating frequency of the wireless power receiving device at different reference K factors, the load voltage and load power of the wireless power receiving device. The information can also indicate the load type and load state of a variable load associated with the wireless power receiving device. The load state represents a composite state of the load voltage and the corresponding load power of the equipment. The TX controller 108 can utilize this information to provide wireless power with characteristics that enable the wireless power receiving device to operate at a relative efficiency from the beginning. For example, the TX controller 108 can select a reference control parameter, such as the frequency of the wireless power, based on the load state information received from the wireless power receiving device. The TX controller 108 can supply wireless power by determining an operational control parameter and controlling a first and a second PWM driver (312 and 314, respectively) based on the operational control parameter. The PWM drivers (312 and 314, respectively) can operate a first switch 316 and a second switch 318. The first switch 316 and the second switch 318 can energize a primary coil 322 to transmit wireless power according to the operational control parameter to a secondary coil of a wireless power receiving device.

[0051] After providing power, the wireless power transmitting device 300 can modify operating parameters based on one or more changing conditions, such as a change in load conditions associated with a load connected to the wireless power receiving device. In response to the change in conditions, the TX controller 108 and the wireless power receiving device can modify their respective configurations to adapt to the change in conditions. For example, the TX controller 108 can determine one or more new operating control parameters (such as the frequency of the wireless power) to adapt to the change in load conditions. The TX controller 108 and the wireless power receiving device can implement their respective configuration changes in response to a synchronization event. In some implementations, the TX controller 108 begins providing the modified wireless power substantially simultaneously with the start of consumption of the modified wireless power in the wireless power receiving device.

[0052] FIG. 4A shows a block diagram conceptually illustrating components of an exemplary TX controller. The TX controller 108 can reside in a wireless power transmitting device, such as any of the wireless power transmitting devices 102 and 300 described with reference to FIG. 1 and FIG. 3, respectively. In FIG. 4A, the TX controller 108 can include an estimator unit 412 configured to determine estimated operating parameters. The estimator unit 412 can use configuration data 402 received from the wireless power receiving device to determine start-up control parameters or reference control parameters as a basis for the estimated operating parameters. In some implementations, the estimator unit 412 can also use the operating K factor 404, the load condition 406, the reference voltage, or any combination thereof to determine the estimated operating parameters.

[0053] As described herein, the wireless power transmitting device can provide power with characteristics (such as a selected frequency) that allow the wireless power receiving device to operate at its relative efficiency. During or after the handshake process, the TX controller 108 can receive configuration data from the wireless power receiving device. The configuration data can include one or more reference control parameters, such as the operating frequency of the wireless power receiving device at different reference K factors and the reference load condition of the wireless power receiving device. The TX controller 108 can determine the operating K factor based on feedback from the wireless power receiving device and information about the transmission voltage during the K factor determination process. Additionally, the TX controller 108 can receive a load state 406 that indicates the current operating condition of the load. The load state is a representation of the load power of the equipment at a particular load voltage. The load state 406 can be related to an estimated power required by the load (also referred to as a load power estimate or estimated load power). The configuration data can indicate the load power estimate at various reference load conditions. When the TX controller 108 receives feedback information from the wireless powered device indicating a load condition (sometimes referred to as load condition feedback), the TX controller 108 can determine a load power estimate using the load condition 406 for a reference load condition that matches the load condition feedback. Additionally, the TX controller 108 can receive a reference voltage that is indicative of the voltage required by the load.

[0054] Before supplying power, the TX controller 108 can determine an operating K-factor based on K-factor feedback information received from the wireless power receiving device. For example, a K-factor determination unit (not shown) can determine an operating K-factor between the wireless power transmitting device and the wireless power receiving device (e.g., under a zero current state of the secondary coil) based on a ratio of a receiving voltage at the secondary coil of the wireless power receiving device to a transmitting voltage at the primary coil measured at the wireless power transmitting device. The receiving voltage and the transmitting voltage may be measured by the wireless power receiving device and the wireless power transmitting device, respectively, at a consistent time, such as a measurement slot associated with a synchronization event. The K-factor determination process may be performed when no current flows through the secondary coil of the wireless power receiving device.

[0055] Further, the TX controller 108 can determine a load power estimate as an estimate of the power required by the load. The load power estimate can be based on a load state 406 received in the feedback information. The load state 406 can be a current or expected load state of the wireless power receiving device. For example, the wireless power receiving device can send a feedback or other message indicating the load state. The TX controller 108 can determine a load power estimate based on the load state 406. Further, the load state can indicate whether the transmitter should remain energized or should be turned off. For example, a load state of a first value (such as "0") can indicate that the receiver is intended to be turned off. To minimize losses, the transmitter electronics are also turned off. In some implementations, the feedback information can indicate a fault condition (not shown) related to an equipment fault. Depending on the type of fault condition, the transmitter can interrupt or reduce the transmission power.

[0056] The estimator unit 412 can determine the estimated operating parameters based on one or more of the configuration data 402, the operating K factor 404, the load condition 406, and the reference voltage (U_RX*) 408. In some implementations, the configuration data can include estimator data. The estimator data can include one or more reference K factors and a reference control parameter (such as an operating frequency) when operating with a reference wireless power transmitting device in one or more conditions. In some implementations, the estimator unit 412 can utilize the operating K factor, the load condition, and the reference voltage to interpolate and extrapolate the estimator data to determine the estimated operating parameters. The estimator unit 412 can provide the estimated operating parameters to the logic unit 418. If the logic unit 418 does not receive a feedback parameter from the feedback controller 414, the estimated operating parameter becomes the operating control parameter. The logic unit 418 can provide the operating control parameter to the PWM controller 416. Based on the operational control parameters, the PWM controller 416 can control a switch driver (not shown in FIG. 4A) to provide wireless power having one or more characteristics (such as a selected frequency).

[0057] In some cases (e.g., in response to changes in load conditions, reference voltages, or both), the TX controller 108 can determine new estimated operating parameters or modify existing estimated operating parameters based on feedback information received from the wireless powered device. In some implementations, the TX controller 108 can coordinate with the wireless powered device to synchronize changes in the estimated operating parameters (such as increasing power) to produce synchronized transmission and consumption of wireless power.

[0058] After providing power to the wireless powered device, the TX controller 108 can utilize feedback information received from the wireless powered device to adjust estimated operating parameters or operational control parameters. The TX controller 108 can utilize such feedback information to compensate for errors in the power estimates, errors in the operational K-factors, and parameter differences between the active wireless powered device and the reference wireless powered device. In response to changed load conditions, the TX controller 108 can determine new estimated operating parameters as described above. The TX controller 108 can also determine feedback parameters based on feedback information received from the wireless powered device. To determine the feedback parameters, the comparator 420 or error calculation unit can determine the difference between the reference voltage 408 and the load voltage 422. In some implementations, the feedback information from the wireless powered device can indicate both the reference voltage 408 and the load voltage 422. The reference voltage 408 can indicate the voltage required by the load, while the load voltage 422 can indicate the measured voltage available to the load. The comparator 420 may determine a load voltage error based on the reference voltage 408 and the load voltage 422. For example, the load voltage error may be a difference between the reference voltage 408 and the load voltage 422. The comparator 420 may provide the voltage error to the feedback controller 414. The feedback controller 414 may determine a feedback parameter based on the voltage error. The feedback parameter may be a value used to adjust the estimated operating parameter (provided by the estimator unit 412) based on feedback information received from the wireless powered device.

[0059] In some implementations, the feedback controller can be implemented as a multi-loop controller with an inner loop and an outer loop. The outer loop takes the voltage error as an input and provides a reference to the inner loop as an output. The inner loop can be based on controlling the current or power in the transmitting coil. For example, the outer loop can provide a reference power as its output, and the inner loop can perform power control to make the average transmitter power (calculated based on multiplying the inverter voltage and current, summing the products, averaging the summed products averaging the products over half an AC cycle) equal to the reference power. The output of the inner loop can be the feedback parameter.

[0060] The feedback parameters may relate to a frequency, a duty cycle, a voltage, or any other suitable characteristic of the wireless power. The feedback controller 414 may provide the feedback parameters to the logic unit 418. In some implementations, the estimated operating parameters have a greater impact on the operating control parameters than the feedback parameters.

[0061] The logic unit 418 may include one or more comparators, adders, subtractors, look-up tables, and any other suitable logic for determining the operational control parameters. The logic unit 418 may receive the operational control parameters and the feedback parameters. The logic unit 418 may determine the operational control parameters based on the estimated operational parameters and the feedback parameters. The operational control parameters may indicate one or more of a frequency, a duty cycle, a voltage, an amount of power, or other suitable characteristics of the wireless power provided to the wireless powered device. In some implementations, the TX controller 108 may coordinate with the wireless powered device to synchronize the transmission and consumption of wireless power.

[0062] FIG. 4B shows a block diagram conceptually illustrating components of an exemplary power transmission controller using power control. The elements in FIG. 4B are identical to the corresponding elements described with reference to FIG. 4A. However, FIG. 4B shows an example in which power control (rather than voltage control) is implemented. The wireless powered device can indicate a requested amount of power 452. The TX controller 108 can determine an actual power to be transmitted using a power calculation 428. The power calculation 428 can include multiplying the instantaneous inverter current and inverter voltage, summing the products, and averaging the summed products over half a cycle of the AC power source to determine an average actual power transmitted. Meanwhile, the wireless powered device can transmit feedback information indicating the requested amount of power 452. The logic unit 430 can compare the average actual power transmitted to the requested amount of power 452 to generate a power error value. The feedback controller 414 can determine a feedback parameter based on the voltage error. FIG. 5 shows a block diagram conceptually illustrating an exemplary format of the feedback information. The feedback information 500 may include a load voltage 511, a load status 512, a header 513, other data 514, and a checksum 515. Some fields may be omitted in various implementations. In a traditional wireless power system, the wireless power receiving device may transmit only a load voltage error and rely on the wireless power transmitting device to adjust the transmitted power based only on the voltage error. However, in a dynamic control technique such as the technique described herein, the feedback information may provide additional information that allows the wireless power receiving device to better coordinate with the wireless power transmitting device to control the transmission of wireless power required by the variable load. For example, the wireless power receiving device may inform the wireless power transmitting device of the current operating state of the variable load by indicating a load status 511. A load status 511 equal to a first value (e.g., 0) may indicate that the variable load is off or idle. A load status 511 equal to a second value (e.g., a non-zero value) may indicate a particular operation associated with the variable load. For example, the load status 511 may indicate an active state of the variable load.Additionally, various values ​​of load state 511 can refer to load settings of a blender. In another example, various values ​​of load state 511 can indicate whether a heating element, a fan, or both of an air fryer are active. Load state 511 can correspond to reference load conditions defined in configuration data (not shown) previously transmitted from the wireless power receiving device to the wireless power transmitting device to enable the wireless power transmitting device to determine estimated operating parameters.

[0063] In addition to the load voltage and load status, the feedback information 500 may include other data 514. A header 513 of the feedback information 500 may describe what type of data is included in the other data 514. FIG. 5 shows an example 502 of other data that may be included in the feedback information. For example, the other data may include a reference voltage, a K-factor voltage measurement (such as the received voltage at the secondary coil during the K-factor determination process), a fault condition, among other examples. A fault condition may be included if a fault exists in the wireless power receiving device, such as an open circuit, an over-voltage detection, an over-current detection, an over-temperature detection, an under-voltage detection, among other examples. Another example fault condition may include an indication that the wireless power receiving device has detected a foreign object in the magnetic field between the wireless power transmitting device and the wireless power receiving device.

[0064] In some implementations, the feedback information 500 may be formatted as a feedback message. FIG. 5 illustrates an example format of a feedback message 501 having a fixed length of 4 bytes. The load status may occupy 3 bits. The header may occupy 4 bits. The load status, the reserved bits, and the header together may occupy the first byte of the feedback message 501. The load voltage may be 8 bits and may occupy the second byte of the feedback message 501. The other data may be 8 bits and may occupy the third byte of the feedback message 501. The checksum may be 8 bits and may occupy the fourth byte of the feedback message 501. The bit lengths and positions of the various fields in the feedback message 501 are provided as examples, and other suitable arrangements are possible. For example, in some examples, the checksum may be omitted.

[0065] FIG. 6 shows a block diagram conceptually illustrating an exemplary wireless power receiving device. In FIG. 6, the wireless power receiving device 600 includes a secondary coil 602. The secondary coil 602 can be connected to a series capacitor 603, an optional series switch 646, and a rectifier 604 that can be connected to a load 608. The rectifier 604 may not be present depending on the type of load. Furthermore, the wireless power receiving device 600 can include a communication interface 626 that can include a second communication coil 628. The communication interface 606 can be connected to an RX controller 624. Once the handshake with the power transmitting device is completed, the series switch 646 can be turned on. Furthermore, the switch can be advantageously used to determine a K factor before the start of power transfer.

[0066] The RX controller 624 can also receive and transmit various information to the wireless power transmitting device via the communication interface 626. The RX controller 624 can receive wireless power receiving device data from a memory (shown as configuration data storage 616). The configuration data can include any of the data listed in Table 1. For example, the configuration data can include reference control parameters such as operating frequencies of the wireless power receiving device at different reference K-factors and wireless power receiving device reference load voltages obtained when the wireless power receiving device was tested on a reference wireless power transmitting device. The configuration data can be transmitted to the wireless power transmitting device by the communication interface 626. Additionally, the RX controller 624 can receive information indicative of a load state and / or a power estimate from the load controller 136. Additionally, the RX controller 624 can receive K-factor voltage measurement information from a first voltage sensor 618 connected to the secondary coil 602. The K-factor voltage measurement information can indicate a peak or root mean square (RMS) voltage at the secondary coil 602 measured during the K-factor determination process. Additionally, the RX controller 624 may receive load voltage information from a second voltage sensor 614 connected to the load 608. The load voltage information may indicate a voltage available to the load 608. Additionally, the RX controller 624 may receive information regarding the current from a current sensor 612 connected to the rectifier 604. The information regarding the current and voltage may indicate an amount of power available to the load 608.

[0067] At various times before, during, or after the transmission of wireless power, the communication interface 626 can transmit the aforementioned configuration data, K-factor voltage measurement information, load voltage information, load status, among other examples, to the wireless power transmitting device. The load controller 136 can control the load 608 according to a load setting 636. The load setting 636 can be a user-selectable setting, such as a temperature setting or a motor speed setting. In some implementations, the load setting 636 can refer to a pattern of load conditions based on the user-selectable setting. For example, the load setting 636 can refer to a pattern of operation of an air fryer in which the heating element, the fan, or both can be operated at various times to achieve the user-selectable setting.

[0068] In some cases, the RX controller 624 may send some or all of the configuration data to the power transmitting controller during a handshake process as described herein. In some cases, the RX controller 624 may send feedback information to the wireless power transmitting device. The feedback information may include one or more of a load status, a reference voltage, a power estimate or request for the load, K-factor voltage measurement information, load voltage information, a fault status, or any combination thereof. A TX controller (not shown) of the wireless power transmitting device may modify the wireless power being transmitted to the wireless power receiving device 600 based on the feedback information.

[0069] In some implementations, a synchronization unit 630 may be associated with the first voltage sensor 618. The synchronization unit 630 may determine a synchronization event and provide a synchronization signal that allows components to synchronize operation. For example, the synchronization unit 630 may determine a synchronization event that indicates no switching in the wireless power transmitting device based on a time point when the coil sensed voltage (at the first voltage sensor 618) is zero. The synchronization event detected by the synchronization unit 630 may be substantially simultaneous with a corresponding synchronization event determined by a synchronization unit (not shown) of the wireless power transmitting device.

[0070] As described herein, the load controller 136 can synchronize the operation of the load 608 with changes in the operational control parameters used by the wireless power transmitting device to transmit wireless power. For example, the load controller 136 can wait for a synchronization event before setting the load 608 according to the changed load condition. If the load type is a motor, this can include switching on / off a relay / switch (not shown in the figure) in the load 608.

[0071] FIG. 7 shows exemplary voltage curves that enable timing synchronization of operations between a wireless power transmitting device and a wireless power receiving device. In FIG. 7, an AC voltage graph 700 shows an AC voltage curve 702. The AC voltage curve 702 can represent an AC voltage from a power supply terminal (herein referred to as an AC power supply or an AC power supply voltage) that supplies power to a wireless power transmitting device. By way of example, the AC power supply frequency can be 50 Hz. In FIG. 7, a DC voltage graph 704 shows a DC voltage curve 706. The DC voltage curve 706 can represent a rectified voltage available after a rectifier in the wireless power transmitting device. Furthermore, the DC voltage curve 706 can also represent the output of a smaller rectifier that is powered from an AC power supply and leads to a bias power supply unit that supplies power to a voltage sensor and / or electronics in the wireless power transmitting device. A line 707 indicates the time point at which the AC voltage curve 702 and the DC voltage curve 706 simultaneously have a voltage of 0V (also referred to as a zero voltage or zero crossing event).

[0072] The wireless power transmitting device may include a synchronization unit that may provide a signal representing the AC voltage curve 702 or the rectified DC voltage curve 706 to the TX controller 108. Near each time point when the AC power supply voltage becomes zero (also called zero crossing), the TX controller 108 may stop transmitting power for a short period of time (such as about 300 microseconds, about 1 millisecond, or any other suitable period of time) by disabling the PWM driver to generate a time slot for other operations. Other operations may include data communication between the wireless power transmitting device and the wireless power receiving device using NFC, a K-factor determination process, or a foreign object detection (FOD) operation. In some implementations, the absence of power transmission to the wireless power transmitting device in these cases may serve as a clock to the wireless power receiving device to synchronize the operation of the wireless power receiving device with the wireless power transmitting device. Thus, the wireless power transmitting device may cooperate synchronously with the wireless power receiving device.

[0073] In some implementations, the zero-crossing events shown as lines 707 are designated as regularly repeating feedback slots, FOD slots, or K-factor determination slots. For example, feedback slots may occur every 20 ms. The remaining zero-crossing events can be designated for FOD operations or K-factor determination processes.

[0074] FIG. 8 illustrates an example voltage curve where the transmission controller of the wireless power transmitting device can be synchronized with the load controller of the wireless power receiving device. More specifically, the TX controller 108 of the wireless power transmitting device and the load controller 136 of the wireless power receiving device can cooperate to synchronize their respective power operations. For example, when providing power to the wireless power receiving device, the TX controller 108 can wait for a synchronization event before starting to transmit power. The synchronization event can be the next time that the AC voltage curve 802 has zero voltage. In response to the synchronization event (e.g., the upcoming zero voltage instance), the TX controller 108 can start transmitting wireless power based on the operation control parameters (as described with reference to FIG. 4A or FIG. 4B). Similarly, the load controller 136 can also wait for a synchronization event before setting a load change and consuming the changed power. In some cases, the TX controller 108 can start transmitting wireless power substantially simultaneously when the load controller 136 sets the load to start consuming wireless power.

[0075] FIG. 8 includes time markers 810 illustrating events in a wireless power system. More specifically, the time markers 810 illustrate events that occur when a load state changes. At time=T0, the load controller 136 can detect a change in the load state. For example, the change in the load state can be initiated by a user changing a knob or other setting in an appliance. In some implementations, communication can occur synchronously to every other zero voltage. At time=T1, when the transmission of power is stopped by the TX controller 108, the load controller 136 can communicate the changed load state to the TX controller 108. Instead of immediately setting the load to correspond to the load state, the load controller 136 can wait for a synchronization event before setting the load.

[0076] Further, at time=T1 (or substantially at time=T1), the TX controller 108 may receive a load status from the load controller 136.

[0077] In the time between time=T1 and time=T2, the TX controller 108 may determine new operational control parameters (e.g., as described with respect to FIG. 4A or 4B). Instead of immediately commencing transmission of wireless power based on the new operational control parameters, the TX controller 108 may wait for a synchronization event.

[0078] At T2, there is zero voltage for the AC voltage curve 802 and the DC voltage curve 806, during which the transfer of power is stopped by the TX controller 108. A synchronization event is detected in both the wireless power transmitting device (e.g., by the TX controller 108) and the wireless power receiving device (e.g., by the RX controller 128 or the load controller 136). In response to the synchronization event, the TX controller 108 starts providing wireless power according to new operational control parameters, and the load controller 136 sets the load to the changed load state. Once switching is resumed by the TX controller 108, the transfer of power to the changed load state can be resumed according to the new operational control parameters (frequency, duty cycle, voltage, etc.).

[0079] FIG. 9 illustrates an example voltage graph 900 for a wireless power system implementing a traditional feedback control technique. The first graph includes a reference load voltage curve 902 representing a desired load voltage at the wireless powered device. The second graph includes an actual load voltage curve 904 representing an average load voltage detected at the wireless powered device's load. These graphs represent voltages at a traditional wireless kitchen system (such as a heating appliance) without the benefits of the present disclosure. Traditional wireless kitchen systems may use traditional feedback control techniques in which changes in wireless power transmission are controlled by feedback messages from the wireless powered device to the wireless powered device after a load condition of the wireless powered device changes. The actual load voltage curve 904 illustrates a response delay in power delivered to the load. At a first time point (shown as T0), power is flowing to the wireless powered device at a first load voltage (V1). At a second time point (shown as T1), the power setting of the appliance is increased. Based on this new power setting, the reference load voltage curve 902 changes from V1 to a second load voltage (V2). A traditional feedback control technique may include a feedback message indicating that the reference load voltage has changed to V2. However, the load may immediately begin drawing power for the second load voltage even though the wireless power transmitting device has not yet determined new operational control parameters based on the new reference load voltage. Therefore, after the reference load voltage 902 increases from V1 to V2 at T1, the actual load voltage curve 904 may take a significant amount of time to reach a new steady state value of V2. As shown in the graph 900, the actual load voltage curve 904 exhibits a sloping curve due to a response delay after T1. At a third time point (shown as T2), the power setting is decreased to indicate a decrease in the reference load voltage setting from V2 to V1. Similar to the response delay to the increase in the reference load voltage, the average load voltage (represented by the actual load voltage curve 904) may take a significant amount of time to reach a new steady state value after the reference load voltage decreases from V2 to V1 at T2.

[0080] FIG. 10 shows an example graph 1000 for a wireless powered system implementing power control according to some implementations of the present disclosure. The first graph includes a reference load voltage curve 1002 representing a desired load voltage at the wireless powered device. The load voltage change at T1 and T2 and the corresponding reference load voltage curve 1002 in FIG. 10 are the same as the reference load voltage curve 1002 described with reference to FIG. 9. The second graph includes an actual load voltage curve 1004 representing an average value of the load voltage detected at the load of the wireless powered device. In contrast to FIG. 9, the average value of the load voltage represented by the actual load voltage curve 1004 in FIG. 10 shows how the load voltage can be affected by the operation of the load controller 136 and the TX controller 108 described herein. When the power is increased (at T1) by the change of the reference load voltage from V1 to V2, the average value of the load voltage (represented by the actual load voltage curve 1004) settles to the load state value of V2 in a relatively short time. Similarly, when the load condition is reduced by decreasing the reference voltage from V2 to V1 at T2, the average load voltage settles to V1 in a relatively short time. The TX controller 108 can determine new operational control parameters based on the change in the load condition voltage, resulting in faster transient behavior. As shown, the features and components described herein can increase responsiveness to power changes and improve the user experience.

[0081] FIG. 11 shows a flow diagram illustrating an example operation of a process for providing wireless power to a wireless power receiving device. For simplicity, the operations are described as being performed by an apparatus. The operations of the process 1100 can be implemented by a wireless power transmitting device described herein. For example, the process 1100 may be performed by the wireless power transmitting device 102 and the TX controller 108 described with reference to FIG. 1, the wireless power transmitting device 300 and the TX controller 108 described with reference to FIG. 3, the TX controller 108 described with reference to FIG. 4A or FIG. 4B, or the apparatus 1700 described with reference to FIG. 19.

[0082] At block 1102, the device may obtain configuration data associated with a variable load, load state, and reference voltages of a wireless powered device.

[0083] At block 1104, the device may initiate transmission of wireless power to the wireless powered device using operational control parameters based at least in part on the configuration data, the load condition, and the reference voltage.

[0084] In block 1106, the device may receive feedback information from the wireless power receiving device during the transmission of wireless power, the feedback information including a load voltage measured by the wireless power receiving device and further indicating a change in the load condition, the reference voltage, or both.

[0085] At block 1108, the device may modify operational control parameters based at least in part on the feedback information.

[0086] 12 shows a flow diagram illustrating an example operation of a process for receiving wireless power in a wireless powered device. For simplicity, the operations are described as being performed by the device. The operations of the process 1200 can be performed by a wireless powered device described herein. For example, the process 1200 may be performed by the wireless powered device 118 and the load controller 136 described with reference to FIG. 1, and the wireless powered device 600 described with reference to FIG. 6.

[0087] At block 1202, the device may transmit configuration data related to the variable load of the wireless power receiving device, load conditions, and reference voltages to the wireless power transmitting device.

[0088] At block 1204, the device may receive wireless power from the wireless power transmitting device based at least in part on the configuration data, the load condition, and the reference voltage.

[0089] In block 1206, the device may transmit feedback information to the wireless power transmitting device during wireless power reception, the feedback information including a load voltage measured by the wireless power receiving device and further indicating a change in the load condition, the reference voltage, or both.

[0090] 13 shows a flow diagram illustrating an example operation of a process in an example wireless powered device having a motor with section windings. For simplicity, the operations are described as being performed by the device. The operations of the process 1200 can be performed by the wireless powered device described herein. For example, the process 1200 may be performed by the wireless powered device 118 and the load controller 136 described with reference to FIG. 1, and the wireless powered device 600 described with reference to FIG. 6.

[0091] In a configuration stage, the device may transmit configuration data to the wireless power transmitting device, block 1310. Table 3 shows an example of configuration data that a wireless power receiving device having a motor with section windings may transmit. Note that the example configuration data includes starting control parameters and control parameter limits, but may not include estimator data. [Table 3]

[0092] Following the configuration phase, the wireless power receiving device may proceed to a connection phase. In block 1320, the device may determine whether the device is on. For example, the device may be turned on with minimal power to allow a user to select user-selectable settings or to allow the device to operate a motor. If the device is off, the process may remain in the connection phase without sending feedback information to the wireless power transmitting device. Alternatively, or in addition, the device may send periodic feedback indicating that the load status is idle or off (e.g., load status=0). However, if the device is on, the process may proceed to a power transfer phase beginning at block 1330.

[0093] In block 1330, the device can transmit the load status, the load voltage, and the reference voltage to the wireless power transmitting device. The wireless power transmitting device uses these values ​​to determine operational control parameters and initiates the transmission of wireless power to support the load. In some implementations, the transmission of wireless power is initiated synchronously with a load controller of the device operating the load.

[0094] At block 1340, the device can receive wireless power and use it to operate a load.

[0095] In block 1350, the device may determine whether the load is still on or has been switched off. For example, a user may turn off the motor or change settings to stop power to the motor, resulting in a determination that the load is no longer on. In that case, the process may proceed to block 1360, where the device transmits feedback information indicating that the load status is off or idle (e.g., load status=0). If the load is still on, the process may proceed to block 1370, where feedback information is transmitted indicating the load status, the load voltage, and other data. The other data may include, for example, a reference voltage that allows the wireless power transmitting device to calculate a voltage error and adjust operational control parameters to meet the reference voltage. The process may return to block 1430, where the device continues to receive and use wireless power to operate the load.

[0096] FIG. 14 shows a flow diagram illustrating an example operation of a process in an example wireless power transmitting device for transmitting wireless power corresponding to the process described with reference to FIG. 13. For simplicity, the operations are described as being performed by the device. The operations of the process 1100 can be implemented by a wireless power transmitting device described herein. For example, the process 1100 may be performed by the wireless power transmitting device 102 and the TX controller 108 described with reference to FIG. 1, the wireless power transmitting device 300 and the TX controller 108 described with reference to FIG. 3, the TX controller 108 described with reference to FIG. 4A or FIG. 4B, or the device 1700 described with reference to FIG. 19.

[0097] At block 1410, the device may detect the presence of a wireless powered device. At block 1420, in a configuration phase, the device may receive configuration data (such as the example configuration data of Table 3). After communicating the configuration data, the wireless power transmitting device and the wireless powered device may enter a connection phase. The connection phase may include a time when the wireless powered device is idle. Proceeding to a power transfer phase, at block 1430, the device may receive a load status, a load voltage, and a reference voltage from the wireless powered device.

[0098] At block 1440, during the power transfer phase, the device can set operational control parameters based on the configuration data. For example, the device can set operational control parameters as start-up control parameters and control the operational control parameters so as not to violate control parameter limits. Additionally, the device can record a reference voltage so that it can be used in ongoing voltage error calculations.

[0099] At block 1450, the device may receive feedback information including the load condition and the load voltage. In some implementations, the feedback information may also include a change in the reference voltage.

[0100] In block 1460, the device may determine whether the load status included in the feedback information indicates that the load is off. For example, if the load status=0, the device may determine that the load is off and may proceed to block 1470 to stop transmitting wireless power. The device may then return to the connected stage and wait for further messages indicating a change in the load status, or may return to the idle state if the device is removed from the interface. However, if in block 1460, the device determines that the load status is not 0, the process may proceed to block 1480.

[0101] At block 1480, the device may adjust the control of the wireless power based on the load voltage and the reference voltage. For example, the device may determine feedback parameters to adjust the operational control parameters to correspond to the difference between the load voltage and the reference voltage. After 1480, the process returns to block 1450.

[0102] FIG. 15 shows a block diagram illustrating the power control operation of an exemplary wireless power transmitting device corresponding to the process described with reference to FIG. 14. The blocks in FIG. 15 are equivalent to the corresponding blocks described with reference to FIG. 4A or FIG. 4B. In this situation, since the configuration data does not include estimator data, the estimator unit 412 can use the start-up control parameter (such as Fstart) as the estimated operating parameter. The control parameter limit can be enforced by the limit unit 1550. Using the exemplary configuration data from Table 3, the start-up control parameter (and thus the estimated operating parameter) can be a start-up frequency of 50 kilohertz (kHz). In some implementations, the estimated operating parameter can be adjusted based on the reference voltage 1508 or based on the characteristics of the wireless power transmitting device. The limit unit 1550 can ensure that the operating control parameter from the logic unit 418 does not fall below the Flimit of 30 kHz indicated in the exemplary configuration data. The limit unit 1550 can also integrate a controller that avoids over-voltage and over-current situations in the power transmitter.

[0103] 16 shows a flow diagram illustrating an example operation of a process in an example wireless powered device associated with an air fryer. For simplicity, the operations are described as being performed by the device. The operations of process 1200 may be performed by a wireless powered device described herein. For example, process 1200 may be performed by wireless powered device 118 and load controller 136 described with reference to FIG. 1, and wireless powered device 600 described with reference to FIG. 6.

[0104] At block 1610, in a configuration stage, the device may transmit configuration data to the wireless power transmitting device. Table 4 shows an example of configuration data that may be transmitted by a wireless power receiving device associated with an air fryer. Note that the exemplary configuration data includes estimator data, but may not include the start-up control parameters and control parameter limits. Table 5 shows exemplary estimator data. The base K factor (represented here as a decimal) may be appropriately scaled to a 5-bit binary representation. [Table 4] [Table 5]

[0105] Following the configuration phase, the wireless power receiving device may proceed to a connection phase. At block 1620, the device may determine whether the device is on. If the device is off, the process may remain in the connection phase without sending feedback information to the wireless power transmitting device. Alternatively, or in addition, the device may send periodic feedback indicating that the load state is idle or off (e.g., load state=0). However, if the device is on, the process may proceed to a power transfer phase beginning at block 1622.

[0106] Blocks 1622 and 1624 show a K-factor determination process 1625 that may be performed before starting the transmission of power or during the K-factor determination time slot. In block 1622, the wireless power receiving device may transmit a message indicating a K-factor measurement request. If the message is formatted according to a feedback message, the feedback message may also include the load status and the load voltage. In block 1624, the device may perform a K-factor determination process. The K-factor determination process may include measuring the received voltage across the secondary coil when no current is flowing through the secondary coil (referred to as a K-factor voltage measurement). The K-factor determination process may include the device transmitting the K-factor voltage measurement to the wireless power transmitting device.

[0107] In block 1630, the device can transmit the load status, the load voltage, and the reference voltage to the wireless power transmitting device. The wireless power transmitting device uses these values ​​to determine operational control parameters and initiates the transmission of wireless power to support the load. In some implementations, the transmission of wireless power is initiated synchronously with a load controller of the device operating the load.

[0108] At block 1640, the device can receive wireless power and use it to operate a load.

[0109] In block 1645, the device may determine whether the load is still on or has been switched off. For example, a user may turn off the motor or change a setting to stop power to the motor, resulting in a determination that the load is no longer on. If so, the process proceeds to block 1660, where the device transmits feedback information indicating that the load status is off or idle (e.g., load status=0). If the load is still on, the process may proceed to block 1650.

[0110] At block 1650, the device may determine whether an additional feedback message is needed. For example, an additional feedback message may be needed if the load condition changes or if the reference voltage changes. If an additional feedback message is needed, the process may proceed to block 1657. At block 1657, the device may prepare a header field and corresponding data for the feedback message. The process may proceed to block 1670. Otherwise, if no additional feedback is needed at block 1650, the process may proceed to block 1670. At block 1670, the device transmits feedback information including the load condition and the load voltage. The feedback information may also include the header and corresponding data from block 1657, if generated.

[0111] FIG. 17 shows a flow diagram illustrating an example operation of a process in an example wireless power transmitting device for transmitting wireless power corresponding to the process described with reference to FIG.

[0112] At block 1710, the device may detect the presence of a wireless power receiving device. At block 1720, in a configuration phase, the device may receive configuration data (such as the example configuration data of Table 3). After communicating the configuration data, the wireless power transmitting device and the wireless power receiving device may enter a connection phase. The connection phase may include a time when the wireless power receiving device is idle. Upon proceeding to the power transfer phase, the device may perform a K factor determination process 1725.

[0113] Blocks 1722 and 1724 show a K-factor determination process 1725 that may be performed before starting the transmission of power or during the K-factor determination time slot. At block 1722, the device may receive a message indicating a K-factor measurement request. If the message is formatted according to a feedback message, the feedback message may also include a load state and a load voltage. At block 1724, the device may perform a K-factor determination process. The K-factor determination process may include applying a transmit voltage across the primary coil. The K-factor determination process may include the device receiving a K-factor voltage measurement from the wireless powered device. The device may calculate an operating K-factor based on the transmit voltage and the K-factor voltage measurement.

[0114] At block 1730, the device may receive the load status, the load voltage, and the reference voltage from the wireless powered device.

[0115] At block 1740, during the power transfer phase, the device can set operational control parameters based on the configuration data. For example, the device can determine estimated operational parameters based on the estimator data, the operational K factor, and the load condition. Additionally, the device can set a reference voltage so that it can be used in ongoing voltage error calculations.

[0116] At block 1750, the device may receive feedback information including the load condition and the load voltage. In some implementations, the feedback information may also include a change in the reference voltage.

[0117] In block 1760, the device may determine whether the load status included in the feedback information indicates that the load is off. For example, if the load status=0, the device may determine that the load is off and may proceed to block 1770 to stop transmitting wireless power. The device may then return to the connection stage and wait for further messages indicating a change in the load status. However, if in block 1760, the device determines that the load status is not 0, the process may proceed to block 1780.

[0118] At block 1780, the device may adjust the control of the wireless power based on the load voltage and the reference voltage. For example, the device may determine a feedback parameter to adjust the operational control parameter to correspond to the difference between the load voltage and the reference voltage. In some implementations, the device may modify the operational control parameter when, for example, the load condition or the operational K factor changes. For example, the device may determine a new estimated operational parameter based on the changed load condition or the changed operational K factor. From the estimated operational parameter, the device may determine the operational control parameter and adjust the operational control parameter as needed based on the reference voltage. After 1780, the process returns to step 1750.

[0119] FIG. 18 shows a block diagram illustrating an example wireless power transmitting device power control operation corresponding to the process described with reference to FIG. 17. The blocks of FIG. 18 are equivalent to the corresponding blocks described with reference to FIG. 4A or 4B. In this situation, since the configuration data 402 includes estimator data, the estimator unit 412 can determine the estimated operating parameters using the estimator data, the operating K factor 404, and the load condition 406. In some implementations, the estimated operating parameters can be adjusted based on the reference voltage 408 or based on the characteristics of the wireless power transmitting device.

[0120] FIG. 19 illustrates a block diagram of an exemplary device for use in a wireless power system. In some implementations, the device 1900 may be a wireless power transmitting device (such as the wireless power transmitting device 102) described herein. In some implementations, the device 1900 may be an example of the TX controller 108 described with reference to FIG. 1, the wireless power transmitting device 300 described with reference to FIG. 3. The device 1900 may include a processor 1902 (possibly including multiple processors, multiple cores, multiple nodes, or a multi-threading implementation, etc.). Additionally, the device 1900 may include a memory 1906. The memory 1906 may be a system memory or any one or more of the possible implementations of the computer-readable media described herein. Additionally, the device 1900 may include a bus 1911 (PCI, ISA, PCI-Express, HyperTransport®, InfiniBand®, NuBus®, AHB, AXI, etc.).

[0121] The apparatus 1900 may include one or more controllers 1962 configured to manage multiple primary or secondary coils (such as a coil array 1964). In some implementations, the controller 1962 may be distributed within the processor 1902, the memory 1906, and the bus 1911. The controller 1962 may perform some or all of the operations described herein. For example, the controller 1962 may be a power transmission controller, such as the TX controller 108 described with reference to FIG. 1 or the TX controller 108 described with reference to FIG. 3.

[0122] The memory 1906 may include computer instructions executable by the processor 1902 to perform the functions of the implementations described with reference to Figures 1-18. Any of these functions may be implemented partially (or fully) in hardware or on the processor 1902. For example, the functions may be implemented by an application specific integrated circuit, in logic implemented in the processor 1902, in a co-processor on a peripheral device or card, etc. Furthermore, an implementation may include fewer components than shown in Figure 19 or may include additional components not shown in Figure 19. The processor 1902, memory 1906, and controller 1962 may be coupled to a bus 1911. Although shown as coupled to the bus 1911, the memory 1906 may be coupled to the processor 1902.

[0123] 1-19 and the operations described herein are examples intended to aid in understanding example implementations and should not be used to limit potential implementations or the scope of the claims. Some implementations may perform additional or fewer operations, may perform operations in parallel or in a different order, and may perform some operations differently.

[0124] The above disclosure provides examples and descriptions, but is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Modifications and variations can be made in light of the above disclosure or may be acquired from practicing the embodiments. Although the embodiments of the present disclosure have been described with reference to various examples, any combination of the embodiments from any of the examples is within the scope of the present disclosure. The examples in this disclosure are provided for educational purposes. Alternatively or in addition to other examples described herein, the examples include any combination of the following implementation options (identified as clauses for reference):

[0125] Terms Clause 1. A method performed by a wireless power transmitting device, the method including: obtaining configuration data for a variable load of a wireless power receiving device, a load state, and a reference voltage; initiating a transmission of wireless power to the wireless power receiving device using operational control parameters based on the configuration data, the load state, and the reference voltage; receiving feedback information from the wireless power receiving device during the transmission of wireless power, the feedback information including a load voltage measured by the wireless power receiving device and further indicating a change in the load state, the reference voltage, or both; and modifying the operational control parameters based on the feedback information.

[0126] Clause 2. The method of clause 1, further including, prior to initiating transmission of wireless power, determining estimated operating parameters based on the configuration data, the load condition, and a reference voltage, and determining operational control parameters based on the estimated operating parameters.

[0127] Clause 3. The method of clause 2, wherein the configuration data includes start-up control parameters, and the estimated operating parameters are based on the start-up control parameters.

[0128] Clause 4. The method of clause 3, wherein the configuration data further includes control parameter limits, and determining the estimated operating parameter includes determining the estimated operating parameter such that the estimated operating parameter is at or above the control parameter limits.

[0129] Clause 5. The method of clause 4, wherein the start-up control parameters include a start-up frequency (Fstart), the control parameter limits include a frequency limit (Flimit), and the estimated operating parameter is an operating frequency based on Fstart and a reference voltage, and the operating frequency is greater than or equal to Flimit.

[0130] Clause 6. The method of clause 2, wherein the configuration data includes one or more reference control parameters associated with one or more reference load conditions, and the estimated operating parameters are based on the reference control parameters associated with reference load conditions matching the load conditions.

[0131] Clause 7. The method of clause 2, wherein the configuration data includes a reference coupling coefficient (K-factor) for each combination of one or more reference control parameters associated with one or more reference load conditions, and determining the estimated operating parameter includes determining an operational K-factor between the wireless power receiving device and the wireless power transmitting device, selecting a particular reference control parameter from the configuration data based on a particular reference load condition that matches the load condition and a particular reference K-factor that matches or approximates the operational K-factor, and determining the estimated operating parameter based on the particular reference control parameter.

[0132] Clause 8. The method of clause 7, further comprising determining an estimated operating parameter based on an interpolation of the two or more reference control parameters when the operating K-factor is between two or more corresponding reference K-factors.

[0133] Clause 9. The method of clause 7 or 8, wherein determining the operational K-factor includes applying a first voltage to a primary coil of the wireless power transmitting device to induce a second voltage in a secondary coil of the wireless power receiving device when no current is present in the secondary coil, receiving a message from the wireless power receiving device indicating the second voltage induced in the secondary coil, and determining the operational K-factor based on a ratio of the second voltage to the first voltage.

[0134] Clause 10. The method of clause 9, wherein the configuration data further includes a number of receiver coil turns in the secondary coil, and determining an operational K-factor further includes calculating an operational K-factor based on multiplying a first operand and a second operand, the first operand being a second voltage divided by the number of receiver coil turns, and the second operand being a number of send coil turns in the primary coil divided by the first voltage.

[0135] Clause 11. The method of any one of clauses 2-10, wherein the estimated operating parameters include an operating frequency.

[0136] Clause 12. The method of any one of clauses 2-11, further comprising, during the transmission of wireless power, modifying the estimated operating control parameters based on changes in a load condition, a reference voltage, or both, and modifying the operating control parameters based on the modified estimated operating control parameters and the reference voltage.

[0137] Clause 13. The method of any one of clauses 1-12, wherein receiving the feedback information includes receiving one or more feedback messages from the wireless power receiving device during one or more corresponding feedback slots, each feedback message including at least a load status field indicating a load status and a load voltage field indicating a load voltage measured by the wireless power receiving device.

[0138] Clause 14. The method of clause 13, wherein the one or more feedback messages include other data fields for indicating at least one member of the group consisting of a reference voltage associated with a load condition of the variable load, a voltage measured at the secondary coil for determining an operating K-factor, a fault condition, and an indication of a foreign object detected by the wireless power receiving device.

[0139] Clause 15. The method of clause 14, wherein the one or more feedback messages include a header field that indicates the type of data contained in the other data fields.

[0140] Clause 16. The method of any one of clauses 13 to 15, wherein the one or more corresponding feedback slots occur at regular intervals during the transmission of wireless power.

[0141] Clause 17. The method of clause 16, wherein the regular intervals are located at zero-crossing events corresponding to an alternating current (AC) power supply voltage.

[0142] Clause 18. The method of any one of clauses 13 to 17, wherein the one or more feedback messages include a checksum field.

[0143] Clause 19. The method of any one of clauses 13 to 18, wherein the one or more feedback messages are each 4 bytes in length and formatted with a fixed bit length associated with each field.

[0144] Clause 20. The method of any one of clauses 1-19, further comprising managing the transmission of wireless power such that modifying an operational control parameter causes a change in the transmission of wireless power associated with a synchronization event in which an alternating current (AC) mains voltage is equal to zero volts.

[0145] Clause 21. The method of any one of clauses 1-20, further comprising receiving configuration data in a first message via a communication coil of the wireless power transmitting device prior to transmission of wireless power via a primary coil of the wireless power transmitting device.

[0146] Clause 22. The method of any one of clauses 1-21, wherein the configuration data includes a control indicator indicating a type of control of the wireless powered device, an indication of the rated device voltage, an indication of the rated device power, an indication of the secondary coil of the wireless powered device and a distance from an interface of the wireless powered device, a number of turns of the powered coil relative to the secondary coil, an indication of a free space inductance of the secondary coil, an indication of a resonant capacitance of the secondary coil, and an estimator data size field.

[0147] Clause 23. The method of clause 22, wherein the configuration data further includes: if the estimator data size field is equal to zero: a start frequency (Fstart) and a frequency limit (Flimit); and if the estimator data size field is a non-zero value: a number of estimator data records based on the non-zero value, each estimator data record including a reference control parameter associated with a reference load condition.

[0148] Clause 24. The method of clause 23, wherein the configuration data further includes, if the estimator data size field has a non-zero value: an indication of a reference wireless power transmitting device used in determining the number of estimator data records.

[0149] Clause 25. The method of any one of clauses 1-24, further including determining that the feedback information includes a load state value indicating a load state is idle or off, and ceasing transmission of wireless power.

[0150] Clause 26. A method performed by a wireless power receiving device, the method including: transmitting configuration data related to a variable load of the wireless power receiving device, a load state, and a reference voltage to a wireless power transmitting device; receiving wireless power from the wireless power transmitting device based on the configuration data, the load state, and the reference voltage; and transmitting feedback information to the wireless power transmitting device during reception of wireless power, the feedback information including the load voltage measured by the wireless power receiving device and further indicating a change in the load state, the reference voltage, or both.

[0151] Clause 27. The method of clause 26, wherein the feedback information causes the wireless power transmitting device to modify an operational control parameter related to wireless power.

[0152] Clause 28. The method of clause 27, wherein the configuration data includes start-up control parameters, and wherein wireless power is received having an operating frequency based on the start-up control parameters.

[0153] Clause 29. The method of clause 28, wherein the configuration data further includes control parameter limits, the start-up control parameters include a start-up frequency (Fstart), the control parameter limits include a frequency limit (Flimit), and the estimated operating parameter is an operating frequency based on Fstart and a reference voltage, and the operating frequency is greater than or equal to Flimit.

[0154] Clause 30. The method of clause 27, wherein the configuration data includes one or more reference control parameters associated with one or more reference load conditions, and wherein wireless power is received using operational control parameters based on the reference control parameters associated with the reference load conditions matching the load conditions.

[0155] Clause 31. The method of clause 27, wherein the configuration data includes a reference coupling coefficient (K-factor) for each combination of one or more reference control parameters associated with one or more reference load conditions, and wherein wireless power is received having operational control parameters based on an operational K-factor between the wireless power receiving device and the wireless power transmitting device associated with a particular reference coupling coefficient of the configuration data.

[0156] Clause 32. The method of clause 31, further including measuring a second voltage induced in a secondary coil of the power receiving device based on a first voltage applied to a primary coil of the wireless power transmitting device when no current is present in the secondary coil, and transmitting a message to the wireless power transmitting device indicating the second voltage measured at the secondary coil, wherein the operating K-factor is based on a ratio of the second voltage to the first voltage.

[0157] Clause 33. The method of clause 32, wherein the configuration data further includes a number of receiver coil turns in the secondary coil, and the operational K-factor is based on a multiplication of a first operand and a second operand, the first operand being a second voltage divided by the number of receiver coil turns, and the second operand being a number of send coil turns in the primary coil divided by the first voltage.

[0158] Clause 34. The method of any one of clauses 26-33, wherein transmitting the feedback information includes transmitting one or more feedback messages to the wireless power transmitting device during one or more corresponding feedback slots, each feedback message including at least a load status field indicating a load status and a load voltage field indicating a load voltage measured by the wireless power receiving device.

[0159] Clause 35. The method of clause 34, wherein the one or more feedback messages include other data fields for indicating at least one member of the group consisting of a reference voltage associated with a load condition of the variable load, a voltage measured at the secondary coil for determining an operating K-factor, a fault condition, and an indication of a foreign object detected by the wireless power receiving device.

[0160] Clause 36. The method of clause 35, wherein the one or more feedback messages include a header field that indicates the type of data that is to be placed in the other data fields.

[0161] Clause 37. The method of any one of clauses 34 to 36, wherein the one or more corresponding feedback slots occur at regular intervals during the transmission of wireless power.

[0162] Clause 38. The method of clause 37, wherein the regular intervals are located at zero-crossing events corresponding to an alternating current (AC) power supply voltage.

[0163] Clause 39. The method of any one of clauses 34 to 38, wherein the one or more feedback messages include a checksum field.

[0164] Clause 40. The method of any one of clauses 34 to 39, wherein the one or more feedback messages are each 4 bytes in length and formatted with a fixed bit length associated with each field.

[0165] Clause 41. The method of any one of clauses 26 to 40, further comprising managing the receipt of wireless power such that changes in the receipt of wireless power occur in relation to a synchronization event.

[0166] Clause 42. The method of any one of clauses 26-41, wherein the configuration data includes a control indicator indicating a type of control of the wireless powered device, an indication of the rated device voltage, an indication of the rated device power, an indication of the secondary coil of the wireless powered device and a distance from an interface of the wireless powered device, a number of turns of the powered coil relative to the secondary coil, an indication of a free space inductance of the secondary coil, an indication of a resonant capacitance of the secondary coil, and an estimator data size field.

[0167] Clause 43. The method of clause 42, wherein the configuration data further includes: if the estimator data size field is equal to zero: a start frequency (Fstart) and a frequency limit (Flimit); and if the estimator data size field is a non-zero value: a number of estimator data records based on the non-zero value, each estimator data record including a reference control parameter associated with a reference load condition.

[0168] Clause 44. The method of clause 43, wherein the configuration data further includes, if the estimator data size field has a non-zero value: an indication of a reference wireless power transmitting device used in determining the number of estimator data records.

[0169] Clause 45. The method of any one of clauses 26-44, further including: determining that a variable load is idle or off; and sending feedback information having a load state value indicating that the load state is idle or off to cause the wireless power transmitting device to stop transmitting the wireless power.

[0170] Clause 46. A wireless power transmitting device configured to carry out the method according to any one of clauses 1 to 25.

[0171] Clause 47. A wireless power receiving device configured to carry out the method according to any one of clauses 26 to 45.

[0172] Another innovative aspect of the subject matter described in this disclosure can be implemented as a computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform any one of the functions described above.

[0173] Another innovative aspect of the subject matter described in this disclosure can be implemented as a system having means for performing any one of the functions described above.

[0174] Another innovative aspect of the subject matter described in this disclosure can be implemented as an apparatus having one or more processors configured to perform one or more operations from any one of the methods described above.

[0175] As used herein, phrases referring to "at least one of" or "one or more of" a list of items refer to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to cover the possibilities of a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b, and c.

[0176] The various example components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware, or software, such as the structures disclosed herein and their structural equivalents. Interchangeability of hardware, firmware, and software has been generally described in terms of functionality and illustrated in the various example components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the particular application and design constraints imposed on the overall system.

[0177] The hardware and data processing devices used to implement the various example components, logic, logic blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed by general purpose single-chip or multi-chip processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices (PLDs), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor may be implemented as a combination of computing devices, such as, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration. In some implementations, certain processes, operations, and methods may be performed by circuitry specific to a given function.

[0178] As mentioned above, some aspects of the subject matter described herein can be implemented as software. For example, various functions of the components disclosed herein, or various blocks or steps of the methods, operations, processes, or algorithms disclosed herein, can be implemented as one or more modules of one or more computer programs. Such computer programs can include non-transitory processor-executable or computer-executable instructions encoded on one or more tangible processor-readable or computer-readable storage media that are executed by or control the operation of a data processing device, including the components of the device described herein. By way of example only and not limitation, such storage media can include RAM, ROM, EEPROM, CD-ROM, or other optical disk storage, magnetic disk storage, or other magnetic storage, or any other medium that can be used to store program code in the form of instructions or data structures. Combinations of the above should also be included within the scope of storage media.

[0179] Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the scope of the present disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with the present disclosure, the principles, and novel features disclosed herein.

[0180] Moreover, various features described herein in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable combination. Thus, although features may be described above as acting in a particular combination and may initially be claimed as such, one or more features from the claimed combination can, in some cases, be deleted from the combination, and the claimed combination can also be directed to a partial combination or a variation of the partial combination.

[0181] Similarly, although operations are shown in the figures in a particular order, this should not be understood as requiring that such operations be performed in the particular order or sequential order shown, or that all of the operations shown be performed, to achieve desirable results. Additionally, the figures may depict one or more exemplary processes generally in the form of a flowchart or flow diagram. However, other operations not shown may be incorporated into the exemplary process depicted generally. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the depicted operations. In some circumstances, multitasking and parallel processing may be advantageous. Additionally, it should be understood that the separation of various system components in the above-described implementations is not to be understood as requiring such separation in all implementations, and that the described program components and systems may generally be integrated together in a single software product or packaged in multiple software products.

Claims

1. A method performed by a wireless power transmitting device, comprising: Obtaining configuration data, load conditions, and reference voltages for a variable load of a wireless power receiving device; initiating a transmission of wireless power to the wireless power receiving device using operational control parameters based at least in part on the configuration data, the load condition, and the reference voltage; receiving feedback information from the wireless power receiving device during the transmission of the wireless power, the feedback information including a load voltage measured by the wireless power receiving device and further indicative of a change in the load condition, the reference voltage, or both; modifying the operational control parameters based at least in part on the feedback information; and The method includes:

2. Before starting the wireless power transmission, determining estimated operating parameters based at least in part on the configuration data, the load conditions, and the reference voltage; determining the motion control parameters based on the estimated motion parameters; The method of claim 1 further comprising:

3. the configuration data includes startup control parameters; The method of claim 2 , wherein the estimated operating parameter is based at least in part on the startup control parameter.

4. the configuration data further includes control parameter limits; The method of claim 3 , wherein determining the estimated operating parameter comprises determining the estimated operating parameter such that the estimated operating parameter is at or above the control parameter limit.

5. The startup control parameters include a startup frequency (Fstart), and the control parameter limits include a frequency limit (Flimit); The method of claim 4 , wherein the estimated operating parameter is an operating frequency based on the Fstart and the reference voltage, the operating frequency being greater than or equal to Flimit.

6. the configuration data includes one or more reference control parameters associated with one or more reference load conditions; The method of claim 2 , wherein the estimated operating parameters are based on reference control parameters associated with a reference load condition that matches the load condition.

7. the configuration data includes a reference coupling coefficient (K-factor) for each combination of one or more reference control parameters associated with one or more reference load conditions; Determining the estimated operating parameters includes: determining an operating K-factor between the wireless power receiving device and the wireless power transmitting device; selecting specific reference control parameters from the configuration data based on specific reference load conditions that match the load conditions and specific reference K-factors that match or approximate the operating K-factors; determining the estimated operating parameters based at least in part on the particular reference control parameters; The method of claim 2 , comprising:

8. determining the estimated operating parameter based on an interpolation of two or more reference control parameters when the operating K-factor is between two or more corresponding reference K-factors; The method of claim 7 further comprising:

9. Determining the operating K-factor includes: applying a first voltage to a primary coil of the wireless power transmitting device to induce a second voltage in the secondary coil of the wireless power receiving device when no current is present in the secondary coil; receiving a message from the wireless power receiving device indicating the second voltage induced in the secondary coil; determining an operating K-factor based at least in part on a ratio of the second voltage to the first voltage; The method of claim 7 or 8, comprising:

10. The configuration data further includes a number of receiver coil turns in the secondary coil; 10. The method of claim 9, wherein determining the operating K-factor further comprises calculating the operating K-factor based on a multiplication of a first operand and a second operand, the first operand being the second voltage divided by a number of turns of the receiving coil, and the second operand being a number of turns of a sending coil in the primary coil divided by the first voltage.

11. The method of any one of claims 2 to 8, wherein the estimated operating parameters include an operating frequency.

12. During the wireless power transmission, modifying the estimated operating parameters based on the changes in the load condition, the reference voltage, or both; modifying the motion control parameter based on the modified estimated motion control parameter and the reference voltage; The method of any one of claims 2 to 8, further comprising:

13. Receiving the feedback information includes: receiving one or more feedback messages from the wireless powered device during one or more corresponding feedback slots, each feedback message including at least a load status field indicative of the load status and a load voltage field indicative of the load voltage measured by the wireless powered device; The method according to any one of claims 1 to 8, comprising:

14. The one or more feedback messages: the reference voltage related to the load condition of the variable load; the voltage measured at the secondary coil to determine an operating K-factor; Fault conditions, and A notification of a foreign object detected by the wireless power receiving device 14. The method of claim 13, further comprising another data field for indicating at least one member of the group consisting of:

15. The method of claim 14 , wherein the one or more feedback messages include a header field that indicates a type of data that goes in the other data field.

16. The method of claim 13 , wherein the one or more corresponding feedback slots occur at regular intervals during the transmission of wireless power.

17. 17. The method of claim 16, wherein the regular intervals are located at zero-crossing events corresponding to an alternating current (AC) power supply voltage.

18. The method of claim 13 , wherein the one or more feedback messages include a checksum field.

19. 14. The method of claim 13, wherein the one or more feedback messages are each four bytes long and formatted with a fixed bit length associated with each field.

20. Managing the transmission of wireless power such that modifying the operational control parameters causes a change in the transmission of wireless power in relation to a synchronization event in which an alternating current (AC) power supply voltage is equal to zero volts. The method of any one of claims 1 to 8, further comprising:

21. receiving the configuration data in a first message via a communication coil of the wireless power transmitting device prior to transmission of the wireless power via a primary coil of the wireless power transmitting device; The method of any one of claims 1 to 8, further comprising:

22. The configuration data includes: a control indicator indicating a type of control of the wireless power receiving device; Display of rated equipment voltage, Display of rated equipment power, An indication of a secondary coil of the wireless power receiving device and a distance from a boundary surface of the wireless power receiving device; the number of receiver coil turns for the secondary coil; an indication of the free space inductance of said secondary coil; an indication of the resonant capacitance of the secondary coil; and Estimator Data Size Field The method according to any one of claims 1 to 8, comprising:

23. The configuration data includes: If the Estimator Data Size field is equal to zero: the starting frequency (Fstart) and the frequency limit (Flimit), and If the Estimator Data Size field has a non-zero value: several Estimator Data Records based on the non-zero value, each Estimator Data Record including a reference control parameter associated with a reference load condition.

23. The method of claim 22, further comprising:

24. The configuration data includes: If the Estimator Data Size field has a non-zero value: an indication of the reference wireless power transmission device used in determining the number of Estimator Data Records.

24. The method of claim 23, further comprising:

25. determining that the feedback information includes a load state value indicating that the load state is idle or off; Stopping the transmission of the wireless power. The method of any one of claims 1 to 8, further comprising:

26. 1. A method performed by a wireless power receiving device, comprising: transmitting configuration data relating to a variable load of the wireless power receiving device, a load state, and a reference voltage to a wireless power transmitting device; receiving wireless power from the wireless power transmitting device based at least in part on the configuration data, the load condition, and the reference voltage; transmitting feedback information to the wireless power transmitting device during reception of the wireless power, the feedback information including a load voltage measured by the wireless power receiving device and further indicating a change in the load condition, the reference voltage, or both; The method includes:

27. 27. The method of claim 26, wherein the feedback information causes the wireless power transmitting device to modify operational control parameters related to the wireless power.

28. the configuration data includes startup control parameters; 28. The method of claim 27, wherein the wireless power is received having an operating frequency based on the startup control parameters.

29. the configuration data further includes control parameter limits; The startup control parameters include a startup frequency (Fstart), and the control parameter limits include a frequency limit (Flimit); 30. The method of claim 28, wherein the estimated operating parameter is an operating frequency based on the Fstart and the reference voltage, the operating frequency being greater than or equal to Flimit.

30. the configuration data includes one or more reference control parameters associated with one or more reference load conditions; 30. The method of claim 27, wherein the wireless power is received using operational control parameters based on reference control parameters associated with a reference load condition that matches the load condition.

31. the configuration data includes a reference coupling coefficient (K-factor) for each combination of one or more reference control parameters associated with one or more reference load conditions; 28. The method of claim 27, wherein the wireless power is received having operational control parameters based on an operational K-factor between the wireless power receiving device and the wireless power transmitting device associated with a particular reference coupling coefficient of configuration data.

32. measuring a second voltage induced in a secondary coil of the power receiving device based on a first voltage applied to a primary coil of the wireless power transmitting device when no current is present in the secondary coil; transmitting a message to the wireless power transmitting device indicative of the second voltage measured at the secondary coil; Further comprising:

32. The method of claim 31, wherein the operating K-factor is based at least in part on a ratio of the second voltage to the first voltage.

33. The configuration data further includes a number of receiver coil turns in the secondary coil; 33. The method of claim 32, wherein the operating K-factor is based on a multiplication of a first operand and a second operand, the first operand being the second voltage divided by a number of turns in the receiving coil, and the second operand being a number of turns in the sending coil in the primary coil divided by the first voltage.

34. Transmitting the feedback information includes: Transmitting one or more feedback messages to the wireless power transmitting device during one or more corresponding feedback slots. Including, The method according to any one of claims 26 to 33, wherein each feedback message includes at least a load status field indicating the load status and a load voltage field indicating the load voltage measured by the wireless powered device.

35. The one or more feedback messages: the reference voltage related to the load condition of the variable load; the voltage measured at the secondary coil to determine an operating K-factor; Fault conditions, and A notification of a foreign object detected by the wireless power receiving device 35. The method of claim 34, including another data field for indicating at least one member of the group consisting of:

36. 36. The method of claim 35, wherein the one or more feedback messages include a header field that indicates a type of data that goes in the other data field.

37. 35. The method of claim 34, wherein the one or more corresponding feedback slots occur at regular intervals during the transmission of wireless power.

38. 38. The method of claim 37, wherein the regular intervals are located at zero-crossing events corresponding to an alternating current (AC) power supply voltage.

39. 35. The method of claim 34, wherein the one or more feedback messages include a checksum field.

40. 35. The method of claim 34, wherein the one or more feedback messages are each four bytes long and formatted with a fixed bit length associated with each field.

41. managing the receipt of wireless power such that changes in the receipt of wireless power occur in relation to synchronization events; The method of any one of claims 26 to 33, further comprising:

42. The configuration data includes: a control indicator indicating a type of control of the wireless power receiving device; Display of rated equipment voltage, Display of rated equipment power, An indication of a secondary coil of the wireless power receiving device and a distance from a boundary surface of the wireless power receiving device; the number of receiver coil turns for the secondary coil; an indication of the free space inductance of said secondary coil; an indication of the resonant capacitance of the secondary coil; and Estimator Data Size Field The method according to any one of claims 26 to 33, comprising:

43. The configuration data includes: If the Estimator Data Size field is equal to zero: the starting frequency (Fstart) and the frequency limit (Flimit), and If the Estimator Data Size field has a non-zero value: several Estimator Data Records based on the non-zero value, each Estimator Data Record including a reference control parameter associated with a reference load condition.

43. The method of claim 42, further comprising:

44. The configuration data includes: If the Estimator Data Size field has a non-zero value: an indication of the reference wireless power transmission device used in determining the number of Estimator Data Records.

44. The method of claim 43, further comprising:

45. determining that the variable load is idle or off; transmitting the feedback information having a load state value indicating that the load state is idle or off, thereby causing the wireless power transmitting device to stop transmitting the wireless power; The method of any one of claims 26 to 33, further comprising:

46. A wireless power transmitting device configured to carry out the method according to any one of claims 1 to 8.

47. A wireless power receiving device configured to carry out a method according to any one of claims 26 to 33.

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