Power state transitions in wireless power systems based on combinations of status indicators

Abstract

This disclosure provides systems, methods, and apparatus for a receiving device to communicate status information to a transmitting device. The receiving device and the transmitting device may support the use of existing combinations of status indicators in the receiving device status field of a message to provide a more appropriate response to fault conditions in the receiving device. In some embodiments, the transmitting device and the receiving device may use existing combinations of indicators in the receiving device status field to indicate that the receiving device is unable to enter a transmit / receive state for receiving power from the transmitting device. This disclosure describes the operation of a transmitting device that, in cooperation with a receiving device, transitions to a power-saving mode, or a transmitting device that transitions to a power-saving mode, when a fault or condition occurs that prevents the receiving device from receiving or using power from the transmitting device.

Description

Technical Field

[0001] The present disclosure generally relates to wireless power transmission, and more specifically to communication between a power transmission device and a power reception device.

Background Art

[0002] A wireless power system may include a power transmission device and a power reception device. For example, the power transmission device may be installed on or in a countertop or other flat surface. The power reception device may be included in, for example, a cordless electric appliance such as a blender, kettle, air fryer, mixer, toaster, etc. The power transmission device may include a primary coil. The primary coil generates an electromagnetic field, and when the secondary coil of the power reception device is placed near the primary coil, it can induce a voltage in the secondary coil. In this configuration, the electromagnetic field may wirelessly transfer power to the secondary coil. Power can be transferred using inductive coupling or resonant coupling between the primary coil and the secondary coil. The power reception device may supply the received power to operate the cordless electric appliance.

Summary of the Invention

[0003] Each of the systems, methods, and apparatuses of the present disclosure has several innovative aspects, and no single one of them alone bears the desirable characteristics disclosed in the present disclosure.

[0004] In one aspect, a method performed by a power transmission device (PTx: Power Transmitter) in a wireless power system includes receiving, from a power reception device (PRx: Power Receiver) in the wireless power system, a communication message including a status field indicating the status of the power reception device, the status field including a plurality of indicators of the status of the power reception device, and controlling a state transition based on a first indicator of the status field indicating whether the power reception device can receive power from the power transmission device and a second indicator of the status field indicating whether a communication error has occurred.

[0005] In one embodiment, a method performed by a power receiving device in a wireless power system includes: determining the current operating condition of the power receiving device; setting a first indicator and a second indicator in the status field of a communication message based on the current operating condition of the power receiving device, wherein the first indicator indicates whether the power receiving device can receive power from a power transmitting device, and the second indicator indicates whether a communication error has occurred; providing the communication message to a power transmitting device of the wireless power system; and receiving a message from the power transmitting device requesting a transition to a power saving mode if the first indicator indicates that the power receiving device cannot receive power from the power transmitting device and the second indicator indicates that no communication error has occurred.

[0006] Details of one or more implementations of the subject matter described herein are shown in the accompanying drawings and the following description. Other features, embodiments, and advantages will become apparent from the description, drawings, and claims. [Brief explanation of the drawing]

[0007] [Figure 1] This is a block diagram of an exemplary wireless power system, including exemplary power transmission and exemplary power receiving equipment. [Figure 2] This is a message flow diagram illustrating an example of a wireless power transmission process. [Figure 3] This is a block diagram conceptually illustrating an exemplary power transmission system. [Figure 4] This is a conceptual block diagram of an exemplary power receiving device. [Figure 5] This is a block diagram conceptually illustrating exemplary power negotiation and control. [Figure 6] This is a block diagram conceptually illustrating a communication protocol. [Figure 7A]This is a conceptual diagram illustrating an example of message encapsulation technology used by a power receiving device to indicate its status. [Figure 7B] This is a conceptual diagram illustrating an example of a power receiving device status field used by a power receiving device to indicate its status. [Figure 8A] This flowchart shows exemplary operation for the interpretation of the power receiving equipment status indicator by the power transmission equipment. [Figure 8B] This flowchart shows exemplary operation for the interpretation of the power receiving equipment status indicator by the power transmission equipment. [Figure 8C] This flowchart shows exemplary operation for the interpretation of the power receiving equipment status indicator by the power transmission equipment. [Figure 8D] This flowchart shows exemplary operation for the interpretation of the power receiving equipment status indicator by the power transmission equipment. [Figure 9A] This flowchart shows an exemplary operation for setting the power receiving device status indicator by the power receiving device. [Figure 9B] This flowchart shows an exemplary operation for setting the power receiving device status indicator by the power receiving device. [Figure 9C] This flowchart shows an exemplary operation for setting the power receiving device status indicator by the power receiving device. [Figure 10] This is a timing diagram illustrating the first example of state transitions in a wireless power system. [Figure 11] This timing diagram shows a second example of state transitions in a wireless power system. [Figure 12] This timing diagram shows a third example of state transitions in a wireless power system. [Figure 13] This timing diagram shows a fourth example of state transitions in a wireless power system. [Figure 14] This is a block diagram of an example device used in a wireless power system. [Modes for carrying out the invention]

[0008] Please note that the relative dimensions in the diagrams may not be drawn to scale.

[0009] The following description relates to specific embodiments for the purpose of illustrating the innovative aspects of this disclosure. However, it will be readily apparent to those skilled in the art that the teachings of this disclosure are applicable in a variety of different ways. The embodiments described can be implemented in any means, apparatus, system, or method for transmitting or receiving wireless power.

[0010] A wireless power system may include a power transmitter (also called a PTx or wireless power transmitter) that is integrated into or positioned on a surface. A wireless power system may also include a power receiver (sometimes called a PRx or wireless power receiver). The power transmitter may include a primary coil configured to wirelessly transmit power over a magnetic field to a secondary coil in the power receiver. In some implementations, the power transmitter may include a primary coil embedded in or fabricated on a surface on which the wireless power receiver can be positioned. The wireless power receiver may include a power receiver for receiving power wirelessly; it may be an electrical appliance (cordless or corded). The secondary coil of the power receiver may acquire wireless energy from the magnetic field and provide it to a power receiving circuit. The power receiving circuit may convert the energy and use it to charge or power a load. The power receiver may be included in or integrated with a cordless electrical appliance having a variable load (e.g., a mixer, heating element, fan, etc.). In some implementations, the power receiver is included in or integrated with a cordless electrical appliance having a fixed load.

[0011] During the power transfer phase, the receiving device may periodically communicate power control to the transmitting device via a communication channel. Power control communication may, among other examples, indicate the presence or status of the receiving device. Power control communication may include power requests, null communications (communications indicating presence without feedback), or receiving device feedback. The transmitting and receiving devices may communicate via Near Field Communication (NFC), Bluetooth®, or other communication technologies.

[0012] This disclosure provides a system, method, and apparatus for a power receiving device to communicate status information to a power transmitting device. In existing systems, a power receiving device can communicate status information to a power transmitting device via a power receiving device status field in a communication message. The power receiving device status field, when set, contains bits indicating various aspects of the power receiving device's status. However, the number of bits in the power receiving device status field is limited. For example, for efficiency, in existing systems, a limited number of individual bits may be used to communicate the status, with each bit associated with a different aspect of the power receiving device's status.

[0013] Since the number of bits in the status field is limited, many different fault scenarios are usually grouped into one bit. For this reason, the technical problem in existing systems is that the faults actually experienced by the power receiving device become ambiguous due to different combinations of operation difficulties. As a result, when the power transmitting device responds to a fault, it may assume the worst-case scenario and take corrective measures that may not actually be necessary. For example, a fault due to a communication error may require re-initialization to mitigate or correct the fault. Other faults due to overheating, overcurrent, or overvoltage may not require a complete re-initialization to mitigate the fault. However, due to the ambiguity of fault determination caused by the limited number of available bits in the power receiving device status field of existing systems, the power transmitting device may assume the worst-case scenario, that is, in some cases, assume a complete re-initialization regardless of whether such re-initialization is necessary to correct the fault. For this reason, it takes unnecessary time to repair the fault, and the user experience may be degraded.

[0014] In addition, with the limited information available to the power transmitting device, the power transmitting device cannot determine with a certain degree of certainty whether the power receiving device needs power resources from the power transmitting device. As a result, it may be necessary to reserve power resources for the power receiving device. As a result, the power resources of the power transmitting device may be wasted by being reserved for a power receiving device that may not be able to use the power resources. Thus, unused power resources cannot be used by other power transmitting devices that share a common input power cable, as in the case of a multi-transmitter hob. As a result, a power receiving device that could have been serviced by another power transmitting device is not serviced.

[0015] Certain aspects of the subject matter described in this disclosure are practicable in practical applications such as power transmission devices and / or power reception devices to achieve one or more technical solutions to the above problems, and can bring potential benefits to existing systems. The power reception device and the power transmission device may support using a combination of existing status indicators in the power reception device status field of the message to provide a more appropriate response to the fault condition of the power reception device.

[0016] For example, the power transmission device and the power reception device can use a combination of existing indicators in the power reception device status field to indicate that the power reception device has entered the power transmission / reception state (Power State) and cannot receive power from the power transmission device. For example, a fault in the power reception device may prevent the transition to the power transmission / reception state, or the power reception device may be receiving power from an alternative power source (e.g., power from the main power supply). In such cases, the power transmission device can send a request to the power reception device to inquire whether the system can transition to the power-saving mode. For example, the power transmission device can send a message to the power reception device requesting a transition to the standby state. If the power reception device responds "Yes" to the request or does not respond, the power transmission device can transition to the standby state, thereby releasing the reserved negotiated power resources for the power reception device. If the power reception device responds "No" to the request, the power transmission device can wait and issue another query. In this case, the power transmission device can avoid re-initializing the connection with the power reception device that occurs in a conventional system, and solve the problem that the power reception device cannot enter the power transmission / reception state or cannot stay in the power transmission / reception state (e.g., overheating, overvoltage, overcurrent, etc.), or wait for the power reception device to indicate that it has entered the power-saving mode (e.g., transition to the standby state). Therefore, the disclosed communication technology enables better handling of faults and error recovery procedures, improving the user experience.

[0017] While the examples in this disclosure are based on wireless power used in kitchen systems, these technologies are applicable to other types of systems. For example, these technologies may be used in wireless power systems associated with other examples such as home appliances, electronic devices, fans, space heaters, speaker systems, air compressors, gardening equipment, or electric vehicle components.

[0018] Figure 1 shows a block diagram of an exemplary wireless power system 100, including an exemplary power transmitter 102 and an exemplary power receiver 118. The power transmitter (sometimes also called “PTx”) is a functional unit that converts electric power into magnetic force. In this disclosure, the power transmitter 102 includes a communication system and other electrical components in addition to the PTx. The power receiver (sometimes also called “PRx”) is part of a wireless power transfer system that converts magnetic force into electric power or heat. In this disclosure, the power receiver 118 includes a communication system and other electrical components in addition to the PRx. The power transmitter 102 and the power receiver 118 may be separated by an interface space 190. In Figure 1, dashed lines represent communications to distinguish them from solid lines that represent electrical circuit lines. The power transmitter 102 includes a primary coil 104. The primary coil 104 may be a wire coil that transmits wireless power (also called wireless energy). The primary coil 104 may transmit wireless energy using an inductive field or a magnetic resonance field. The primary coil 104 may be associated with the power transmission circuit 110. The power transmission circuit 110 may include components such as a pulse width modulator or voltage-controlled oscillator 142, an inverter 144, and a series capacitor 146. The series capacitor 146 and the primary coil 104 may also be called the "tank circuit 147". The power transmission circuit 110 may include other components (not shown) for impedance matching. The power transmission device 102 may include one or more sensors 152, such as a voltage sensor and a current sensor (not shown).

[0019] Part or all of the power transmission circuit 110 may be embodied as an integrated circuit (IC) implementing features of the present disclosure for controlling and transmitting wireless power to one or more power receiving devices. The power control unit 108 may be implemented as a microcontroller, a dedicated processor, an integrated circuit, an application-specific integrated circuit (ASIC), or any other suitable electronic device.

[0020] The power supply 112 may supply power to the power transmission circuit 110 within the power transmission device 102. The power supply 112 may convert alternating current (AC) power to direct current (DC) power. For example, the power supply 112 may include a converter that receives AC power from an external power source and converts it to DC power used by the power transmission circuit 110.

[0021] The power control unit 108 is connected to a first communication interface 114. In some embodiments, the first communication interface 114 may be an interface that utilizes wireless communication technology to communicate with other wireless communication interfaces (e.g., a second communication interface 132). 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 may be collectively referred to as a first communication unit 124. In some implementations, the first communication unit 124 may support Near-Field Communication (NFC), a technology in which data transfer is performed at a carrier frequency of 13.56 megahertz (MHz). The first communication unit 124 may support any suitable communication protocol.

[0022] The power receiving device 118 may include a secondary coil 120, a series capacitor 122, a series switch 123, a rectifier 126, an electrical appliance control unit 136, a second communication interface 132, a sensor 162, a load 130, and memory (not shown). The series capacitor 122 and the secondary coil 120 may also be referred to as the "tank circuit 121". In some embodiments, the second communication interface 132 may be an interface that communicates using wireless communication technology. In some implementations, the power receiving device 118 may include a user interface (not shown) or other means for obtaining a load setting 164 indicating the desired operation of the load. In some implementations, the load setting 164 may be stored in the power receiving device 118's memory (not shown). In some implementations, the load 130 may include a drive unit (not shown) for controlling at least one parameter of the load, such as temperature, speed, or torque. In some implementations, the rectifier 126 may be omitted. Although shown as different components, some components may be packaged or implemented in the same hardware. For example, in some implementations, the electrical appliance control unit 136 and the power receiving control unit (not shown) may be implemented as a single control unit. The electrical appliance control unit 136, or any combination thereof, may be implemented as a microcontroller, a dedicated processor, an integrated circuit, an application-specific integrated circuit (ASIC), or other suitable electronic device.

[0023] The interface space 190 can demarcate the space between the power transmitting device 102 and the power receiving device 118. For example, the interface space may include the surface of the power transmitting device 102 on which the power receiving device 118 may be located. The distance between the primary coil 104 and the secondary coil 120 may include the thickness of the surface in the interface space 190. During wireless power transfer, the primary coil 104 may induce a magnetic field (called the primary magnetic field) through the interface space 190 into the operating environment on which the secondary coil 120 is located. Thus, the “operating environment” is defined by the primary magnetic field in the system, and the primary magnetic field of the primary coil 104 is detectably present and can detectably interact with the secondary coil 120.

[0024] The power control unit 108 may detect the presence or proximity of the power receiving device 118. This detection may occur during the periodic pinging of the first communication interface 114 in the power transmission device 102. Also, if the power receiving device 118 is nearby during the pinging, the first communication interface 114 may supply power to the second communication interface 132 (via the second communication coil 134) (via the first communication coil 116). The second communication interface 132 may "wake up," supply power to the appliance control unit 136, and send a response signal to the first communication interface 114. A handshake process may take place before the power transfer, during which the power control unit 108 may receive data configuration related to the power rating of the power receiving device, among other information.

[0025] Different cordless electrical appliances may have different load types, different load conditions, 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 conditions to control the motor's rotation speed. Depending on the load condition, 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 conditions to control the temperature. In yet another example, an air fryer is a composite load device that may operate a heater, a fan, or both during various operating periods. Each type of load (motor, resistive load, heater, fan, or any combination thereof) may require different amounts of power to operate depending on the current load condition or load conditions. Furthermore, depending on the load type or load condition, cordless electrical appliances may have different levels of voltage gain from the primary coil to the receiving coil at different primary coil excitation frequencies (e.g., radio power transfer frequencies). For example, to achieve a desired load voltage, a cordless blender can operate optimally at a first operating frequency under a first load condition, such as a low motor speed setting. However, as the load condition changes, the cordless blender may not be able to achieve the same load voltage when operating 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 (e.g., a low speed setting), but may provide a lower voltage gain when the cordless blender is set to a second setting (e.g., a high speed setting). The load setting 164 may indicate the current load condition or the power required for the load to operate under the load condition.

[0026] The power control unit 108 may control the characteristics of the radio power that the transmission unit 102 provides to the power receiving unit 118. After detecting the power receiving unit 118, the power control unit 108 may receive setting data from the power receiving unit 118. For example, the power control unit 108 may receive setting data during the handshake process with the power receiving unit 118. The power control unit 108 may use the setting data to determine at least one operating parameter (e.g., frequency, duty cycle, voltage, etc.) of the radio power generated by the transmission unit circuit 110. During radio power transfer, the operating parameter may be adjusted based on feedback information from the power receiving unit 118 in response to changes in the load state or power requirements of the load 130. Thus, the power control unit 108 may provide radio power that enables relatively efficient operation of the power receiving unit 118. For example, the transmission control unit may set the radio power to operate at peak efficiency for a specific load state, load voltage, and operating K-factor.

[0027] The power transmission device 102 and the power receiving device 118 may implement a control architecture for managing the wireless power transfer. The control architecture may define how power requirements are communicated and how the operating point of the power transmission device is controlled. In some implementations, the control architecture may be based on static power control (also called “Control Type 1 Architecture” or “Type 1”). In some implementations, the control architecture may be based on dynamic power control (also called “Control Type 0 Architecture” or “Type 0”). An electrical appliance implementing a Control Type 1 architecture may have a fixed load, may not include metering circuits, may not employ auxiliary data transfer, and may require only minimal functionality to keep manufacturing costs down. The Control Type 1 architecture may rely on the control loop of the power transmission device 102 without feedback from the power receiving device 118. An electrical appliance implementing a Control Type 0 architecture may have a static or dynamic load and may implement a control unit for generating power request messages during power transfer, and metering circuits for proper control of the load. This disclosure includes examples of both Type 0 and Type 1 control architectures relating to transitions between various operating phases.

[0028] In some implementations, the first communication interface 114 may communicate with the powered device by transmitting a radio communication signal and detecting changes in the radio communication signal that represent the communication of information. The first communication interface 114 may support the NFC Type 2 tag specification or the NFC Type 4A tag specification as defined by the NFC specification. During the power transfer phase, both the communication carrier and the power signal may be active. Due to the frequency range used for the power signal, the intermodulation products of the two signals cause interference that hinders reliable NFC communication. To avoid this undesirable effect, the power signal may be periodically turned off at short time intervals. These time intervals may be called communication time slots. Typically, communication time slots may occur in relation to zero-crossing events associated with the AC mains or AC cycle of a wall plug.

[0029] The second communication interface 132 may support the NFC Type 2 tag specification or the NFC Type 4A tag specification as defined by the NFC specification. In some implementations, the wireless communication unit is configured to communicate with the power transmission unit by storing information in a passive tag (such as an NFC Type 2 tag) that can be read by the power transmission unit's wireless communication interface. Alternatively, the wireless communication unit may be configured to communicate with the power transmission unit by transmitting information (e.g., using an NFC Type 4A Tag) via a wireless communication signal to the power transmission unit's wireless communication interface.

[0030] Figure 2 shows a message flow diagram 200 of an exemplary wireless power transmission process. Referring to Figure 2, the power transmission device 102 detects that the power receiving device 118 is in a charging area in standby mode (operation 205). There are various methods by which the power transmission device 102 can detect the power receiving device 118, and this disclosure does not limit such methods. For example, the power transmission device 102 may detect that the power receiving device 118 is in a charging area by periodically emitting an analog ping of a specific frequency and based on a detected current, resonant shift, or capacitance change. As another example, the power transmission device 102 may periodically transmit a detection signal, and the power receiving device 118 may transmit a response signal (e.g., a control error packet or a signal strength packet). The power transmission device 102 may detect that the power receiving device 118 is in a charging area based on receiving the response signal within a predetermined time following the detection signal. As yet another example, the power receiving device 118 may transmit a search signal or an advertisement signal to the power transmitting device 102. The search signal or advertisement signal may conventionally be transmitted using short-range radio frequency communication (e.g., NFC or Bluetooth®). The power transmitting device 102 may detect the power receiving device 118 based on the reception of the search signal or advertisement signal.

[0031] In some implementations, as a preparatory step for wireless power transmission, the power transmitter 102 may optionally send an information request signal to the power receiver (operation 210). The information request signal may request an ID and power information for the power receiver 118. For example, the information request signal may be transmitted in the form of a data packet message. As another example, the information request signal may be transmitted in the form of a digital pin according to a predetermined standard between the power transmitter 102 and the power receiver 118. In response to the information request signal, the power receiver 118 may send an ID and configuration information to the power transmitter 102 (operation 220). For example, the configuration information may include the requested or maximum amount of power to be provided to the power receiver 118. In some implementations, the configuration information may include a rated power value associated with the load or associated with the operation of the load. In some implementations, the configuration information may also include a time parameter. For example, the time parameter may indicate the expected time for the power receiver to complete its operation based on the rated power value. In some implementations, information request signals, IDs, and configuration information may be communicated using out-of-band communication (communication separate from the radio power signal), such as NFC or Bluetooth.

[0032] The power transmission device 102 sets parameters for power transmission (called the operating point) based on the ID and configuration information and wirelessly transmits power to the power receiving device 118 (operation 230). For example, the power transmission device may create a power transmission contract based on the ID and configuration information and control wireless power transmission according to the power transmission contract. The process by which the power transmission device 102 wirelessly transmits power to the power receiving device, from start to finish, may be called the (wireless) power transfer phase 235. In some implementations, the power receiving device 118 may supply the received wireless power to an external load, such as a heater, motor, or battery. In some implementations, the operation of the power receiving device 118 may be based on an external load and user-configurable settings. For example, operations may include boiling water, baking bread, cooking food, etc. In other examples, operations may be based on charging a battery or other energy storage device to a desired level.

[0033] The power transmission device 102 monitors the parameters for power transmission (operation 245), and may terminate wireless power transmission if any one of the parameters exceeds a specified limit (operation 250). Alternatively, the wireless power transmission process of operation 230 may be terminated at the request of the power receiving device 118. For example, once the power receiving device 118 has completed its operations, it may send a signal to the power transmission device 102 requesting the termination of wireless power transmission.

[0034] During the power transfer phase 235, the receiving device 118 periodically transmits power control communications to the transmitting device 102 (as shown in operations 240-1, 240-2, 240-3, and 240-4). Examples of power control communications include control error packets (CEPs), power request messages, or status messages. This is done to control the amount of power transmitted from the transmitting device 102 to the receiving device 118, i.e., to perform power control.

[0035] In some embodiments, the power transmission device 102 monitors the status field of the power control communication and checks for an indicator indicating a communication error (operation 245). If the indicator persists for a threshold time, the power transmission device 102 stops transmitting power to the power receiving device 118 (operation 250) and transitions to a reinitialization state.

[0036] Figure 3 is a block diagram conceptually showing an exemplary power transmission device 300. The power transmission device 300 may be an example of the power transmission device 102 described with reference to Figures 1 and 2, respectively. The power transmission device 300 may include a power supply 302, indicated as an AC power supply. However, the power supply 302 may be a DC power supply or any other suitable power supply. The power supply 302 may be connected to a rectifier 304 (which may also be called a bridge rectifier or other related terminology). The rectifier 304 may be connected to a capacitor 306. The rectifier 304 may supply DC power to a first switch 316 and a second switch 318. The first switch 316 and the second switch 318 form an inverter 311 that generates an AC voltage from the DC power. The first switch 316 and the second switch 318 may, as other examples, be metal-oxide-semiconductor field-effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs). The first switch 316 is connected to a first pulse width modulation (PWM) driver 312, and the second switch 318 is connected to a second PWM driver 314. The power control unit 108 may be connected to the first PWM driver 312 and the second PWM driver 314. The power control unit 108 may, as another example, control the PWM drivers 312 and 314 to perform wireless power transmission according to a desired operating duty cycle or operating frequency. The power transmission device 300 may include other components (e.g., a capacitor 320) in the path between the power supply 302 and the primary coil 322. The rectifier 304, capacitor 306, switches 316 and 318, and capacitor 320 are sometimes collectively referred to as the power transmission device circuit (PTx circuit) 350. The power control unit 108 controls one or more components of the PTx circuit 350 to manage the transmission of wireless power.

[0037] The power control unit 108 may communicate with the power receiving device via a communication unit. The communication unit may include a communication interface 326, a communication coil 328, and a communication control unit (not shown) or other components connected to it. In some implementations, the communication interface 326 and the communication coil 328 are configured to communicate using the NFC communication protocol. In some implementations, the communication interface 326 and the power control unit 108 may be located on a common processor or chip.

[0038] The power control unit 108 may detect the power receiving device in the vicinity of the primary coil 322 and perform a handshake process in which the power control unit 108 receives information from the power receiving device. The power control unit 108 may receive information via the communication interface 326. In some implementations, the information may include one or more reference control parameters, such as the operating frequency, load voltage, and load power of the power receiving device at various reference coupling coefficients (K-factors). In some implementations, the information may indicate the load type and load state of a variable load associated with the power receiving device. The load state represents the combined state of the appliance, with respect to the load voltage and the corresponding load power. The power control unit 108 may use this information to supply wireless power that has characteristics that enable the power receiving device to operate. For example, the power control unit 108 may supply wireless power by determining the operating parameters and controlling first and second PWM drivers (312 and 314) based on the operating parameters. The PWM drivers (312 and 314) may operate the first switch 316 and the second switch 318. The first switch 316 and the second switch 318 can energize the primary coil 322 to transmit wireless power to the secondary circuit of the power receiving device according to operating parameters.

[0039] The power transmission device 300 may include a measurement unit 308. The measurement unit 308 may measure one or more characteristics (such as voltage, current, or both) via the PTx circuit 350. In some implementations, the measurement circuit may be connected to a rectifier (either to the power supply 302 side or to the wireless power transmission circuit side, as shown in Figure 3). In some implementations, the measurement unit 308 may be configured to measure voltage and current through the rectifier 304 or inverter 311.

[0040] Figure 4 is a block diagram conceptually showing an exemplary power receiving device 400. The power receiving device 400 may be an example of the power receiving device 118 described with reference to Figures 1, 2, and 3. The power receiving device 400 includes a secondary coil 402. The secondary coil 402 may be connected to a rectifier 404 and a capacitor 406. In some implementations, the secondary coil 402 is connected to the rectifier 404 via a series capacitor (not shown), a series switch (not shown), or other electrical components. The rectifier 404 may be electrically coupled to a load 408 or an energy storage device (not shown, e.g., a battery) via a series switch (not shown). In some implementations, the rectifier 404, the capacitor 406, or both may not be present in the power receiving device, depending on the type of load 408 (e.g., a heating element). The power receiving device 400 may include a communication interface 426, which includes a second communication coil 428. The communication interface 426 may be connected to a power receiving device (RX) control unit 424.

[0041] The power receiving device control unit 424 may receive various information and determine control error values, power requirements, or other feedback to transmit to the power transmission device via the communication interface 426. In Figure 4, dotted lines represent control lines or information lines to distinguish them from solid lines representing electrical circuit lines. Control lines or information lines may include electrical connections between the power receiving device control unit 424 and other components of the power receiving device 400. In some implementations, the power receiving device control unit 424 may receive information indicating load settings, power requirements, or power estimates from a load control unit (not shown) connected to the load 408. The power receiving device control unit 424 may also receive voltage information from a voltage sensor 414 connected to the rectifier 404. The voltage information may indicate the voltage available to the load 408.

[0042] The RX control unit 424 may also communicate with the power transmission unit via the communication interface 426. In some implementations, the RX control unit 424 may obtain configuration data from memory (not shown). The configuration data may be transmitted to the power transmission unit via the communication interface 426. The RX control unit 424 may obtain information indicating the load state and / or power estimate from the load control unit (not shown) or the user interface (not shown). At various points before, during, or after the wireless power transfer, the communication interface 426 may transmit to the power transmission unit, in addition to the configuration data, voltage measurement information, coupling information, power request information, load voltage information, load state, etc. Load settings may be user-selectable settings such as temperature settings, cooking time, or motor speed settings. In some implementations, the configuration data may include rated power values ​​and time parameters associated with the operation of the load 408. For example, the time parameter may indicate the estimated time to boil water, toast bread, or cook food based on the load settings. In some examples, the RX control unit 424 may send some or all of the configuration data to the transmitting controller during the handshake process, as described herein. In some examples, the RX control unit 424 may send feedback information to the power transmission unit. The feedback information may include one or more of the following: load conditions, reference voltage, power estimate or request for the load, coupling coefficient information, load voltage information, fault conditions (if detected by the exemplary power receiving unit 400), or any combination thereof.

[0043] The PTx control unit (not shown) of the power transmission device may change the radio power transmitted to the power receiving device 400 based on feedback information. The communication interface 426 may be configured to communicate messages to the power transmission device in predetermined communication slots. For example, the communication slot may be determined based on a synchronization unit (not shown), a clock, or other device. For example, the communication slot may occur when no switching is occurring in the power transmission device and may be determined when the coil detection voltage (voltage in the secondary coil 402) is zero.

[0044] Figure 5 shows an exemplary system state diagram 500 with exemplary power negotiation operation. The system state transition diagram 500 consists of five main states: standby state 510, discovered state 520, connected state 530, transmitting / receiving state 540, and reinitialization state 550. The power transmission unit enters standby state 510 when a user connects the power transmission unit to the main power supply. In standby state 510, the power transmission unit searches for the presence of an active power receiving unit. The power transmission unit maintains standby state 510, waiting for an event that will trigger a transition to discovered state 520. Examples of such events include user interaction with the power transmission unit or the detection of a power receiving unit. For example, if the power transmission unit detects the presence of a power receiving unit, the power transmission unit transitions to discovered state 520.

[0045] In discovery state 520, the power transmission device performs object classification and obtains configuration information about the detected device. For example, the power transmission device can perform NFC object classification and NFC activation and read static settings via the NFC Data Exchange Format (NDEF). If an NFC-A device is found, the power transmission device reads the NDEF record to determine whether the NFC-A device is a power receiving device and obtains static configuration information.

[0046] After successfully detecting the power receiving device in the detection state 520, the power transmitting device transitions to the connection state 530. In this state, the power transmitting device and the power receiving device exchange information to negotiate parameters related to wireless power transfer or wireless charging.

[0047] The following outlines the power negotiation process. The receiving device may communicate a requested power negotiation value to the transmitting device. The requested power negotiation value may be based on the power rating of the load. The receiving and transmitting devices may negotiate guaranteed power based on the requested power negotiation value and the available power of the transmitting device. The transmitting device may accept or reject the requested power negotiation value as guaranteed power. For example, the transmitting device may accept the requested power negotiation value as guaranteed power if the available power is greater than the sum of the requested power negotiation value and the estimated transmission loss (PTx-loss). Alternatively, the transmitting device may not be able to accept the requested power negotiation value. For example, the transmitting device may determine that the available power is less than the sum of the requested power negotiation value and the estimated PTx loss. The transmitting device may communicate a message to the receiving device indicating that the transmitting device has rejected the requested power negotiation value. In some implementations, the receiving device may communicate subsequent requested power negotiation values ​​and wait to see whether the requested power negotiation value will be accepted as guaranteed power. In some implementations, the transmission unit may calculate an alternative power negotiation value that it can satisfy based on the available power. The transmission unit may communicate the alternative power negotiation value (sometimes called the proposed power negotiation value) to the receiving unit. If the receiving unit accepts the alternative power negotiation value as a guaranteed value, it may return an acknowledgment in response.

[0048] Once guaranteed power is negotiated, a transmission unit may reserve the negotiated power from the available power (based on the sum of guaranteed power and estimated PTx losses), thereby reducing the power of other transmission units that share the total power source. Each transmission unit may use the remaining available power after reservations from other transmission units to negotiate similar power (and reserve negotiated power) with its respective receiving units. Because the negotiated power takes estimated PTx losses into account, the total power usage by multiple transmission units will not exceed the maximum power of the power source.

[0049] From the connected state 530, the receiving device can request the transmitting device to transition to the transmit / receive state 540, the standby state 510, or the reinitialization state 550. In the transmit / receive state 540, the transmitting device can perform a foreign object detection (FOD) operation, then apply a power signal to transmit radio power to the receiving device, and repeat this cycle throughout the transmit / receive state 540. Communication or FOD is performed during a slot of power signals. Some examples of communication in the transmit / receive state 540 may relate to power control. For example, during the transmit / receive state 540, the receiving device may communicate a power request (P request) message (sometimes called a "requested power" or CTRL / rpl) to the transmitting device to cause the receiving device to adjust the power level of the radio power transfer. The requested power in the power transfer phase does not need to exceed the guaranteed power previously negotiated between the transmitting and receiving devices. Communication or FOD may transition to a different state.

[0050] In reinitialization state 550, the power transmission unit stops communication with the power receiving unit and power supply, and reinitializes the system. During this reinitialization, the power transmission unit temporarily suspends communication and power transfer for a reinitialization timeout period (e.g., 500 ms) before moving to discovery state 520. The reinitialization timeout period may be used by the power receiving unit to complete the reset.

[0051] Examples of conditions that may cause the system to transition to reinitialization state 550 include: • The power transmission or receiving equipment detects a communication error. • The power receiving device will be removed. • The power receiving device is disconnected from the load during power transfer.

[0052] Figure 6 shows a block diagram 600 conceptually illustrating a communication protocol. The power transmitter 102 may communicate with the power receiver 118. The communication protocol may include a message 620 from the power transmitter 102 to the power receiver 118, a message 610 from the power receiver 118 to the power transmitter 102, or both. This disclosure includes several extensions of the communication protocol to support various functions of a wireless power system. In some implementations, the communication protocol is implemented using NFC communication units in the power transmitter 102 and the power receiver 118. In some implementations, communication between the power transmitter 102 and the power receiver 118 may be performed by READx and WRITEx commands. The power transmitter 102 may issue a READx command to receive a message frame from the power receiver 118. The power transmitter 102 may issue a WRITEx command to send a message frame to the power receiver 118.

[0053] Figure 7A is a conceptual diagram illustrating an example of a message encapsulation technique 700 for a power receiving device to indicate its status. In some embodiments, a communication message frame 708 provided from the power receiving device to the power transmitting device in response to a READx command may include one or more messages 706. Message 706 may include a corresponding payload 704. The message frame 708 from the power receiving device to the power transmitting device may also include a status field 710 (e.g., PRx status) provided before one or more messages 706.

[0054] Figure 7B is a conceptual diagram showing an example of a Power Receiver Status field for indicating the status of a power receiving device. The status field 720 in Figure 7B may be an embodiment of the status field 710 in Figure 7A.

[0055] The status field 720 may contain one or more indicators. In some implementations, the status field 720 is a single byte with various bits assigned to status values ​​or indicators. In some examples, the status indicator 722 of the status field 720 may contain one or more of the following indicators / values ​​for the powered device. • PSTP: Power Shutdown Request (a request from the receiving device during power transfer, indicating that the transmitting device should stop the power transfer). • COMM_ERR: Communication error detected. • LD_CNCTD: A status indicating whether the load on the power receiving device is connected or disconnected.

[0056] The exemplary PRx status indicators are provided for educational purposes only and are not intended to be an exhaustive or exclusive list. Furthermore, some implementations may omit or include various examples of the PRx status indicators described herein. In some embodiments, the NPB (No Power Bit) may be used instead of the PSTP (Power Stop) bit to indicate that the receiving device is unable to receive power from the transmitting device.

[0057] Figure 8A is a flowchart 800 illustrating exemplary operation for the interpretation of the receiving device status indicator by the power transmission device. The power transmission device can receive a communication message from the receiving device (block 802). The communication message may include a status field indicating the status of the receiving device. The status field may include multiple indicators of the receiving device status. For example, the status field may include the indicators described above with respect to Figures 7A and 7B.

[0058] After receiving a message, the power transmission device can control state transitions based on a first indicator in the status field that indicates whether the power receiving device can receive power from the power transmission device, and a second indicator in the status field that indicates whether a communication error has occurred (block 804).

[0059] Figure 8B is a flowchart 820 illustrating exemplary operation for interpreting the power receiving device status indicator while the power transmission device is connected. The power transmission device can receive a communication message from the power receiving device (block 824). The communication message may include a status field indicating the status of the power receiving device. The status field may include multiple indicators of the power receiving device's status. In the example shown in Figure 8B, the first indicator indicates that the power receiving device is not receiving power from the power transmission device. The second indicator may indicate that there are no communication errors between the power transmission device and the power receiving device.

[0060] An indicator that a power receiving device is not receiving power from a power transmitting device may indicate that the power receiving device cannot transition from a connected state to a transmitting / receiving state. A power receiving device may also indicate that it should not receive power from a power transmitting device for various reasons. For example, a fault in the power receiving device may prevent it from receiving or using power transmitted by the power transmitting device. As another example, a power receiving device may be a hybrid device that can receive power from a wired power source (e.g., a mains power source) or a wireless power source (e.g., a power transmitting device). If the power receiving device receives power from a wired power source, it may indicate that it does not receive power from a power transmitting device because it is already receiving power from another power source, such as a wired power source.

[0061] After receiving a message from the receiving device indicating that the transmitting device should not transmit power to the receiving device, the transmitting device may send a message to the receiving device requesting a transition to a power-saving mode (block 826). In some implementations compliant with the Ki Cordless Kitchen Wireless Power Specification, the transmitting device may request the receiving device to agree to a transition to the standby state by sending a “NEXT / stb” message (indicating a request for a state transition, indicating that the requested next state is standby). The sender of the “NEXT” message requests the receiver to move to another state or trigger an action. The receiver of the NEXT message typically acknowledges the request (affirmative or negative) by responding with a response (“RESP”) message. For example, the receiving device may agree that the transmitting device (and the receiving device) will transition to the standby state. Alternatively, the receiving device may indicate that the receiving device does not agree to a transition to the standby state, in which case the transmitting and receiving devices maintain their connection.

[0062] The power transmission device can determine whether or not to receive a response to a message requesting a transition to power-saving mode (decision block 828). For example, the power transmission device may request the power receiving device to transition to a standby state. If the power transmission device does not receive a response to the request (branch "NO" in block 828), the power transmission device can enter a standby state (block 832).

[0063] If the power transmission unit receives a response to the request (the "YES" branch in block 828), the power transmission unit can determine whether the power receiving unit's response to the message indicates consent to the transition to power-saving mode (block 830). If the power receiving unit consents to the transition to power-saving mode (the "YES" branch in block 830), the power transmission unit enters a standby state (block 832). Upon entering the standby state, the power transmission unit releases the power reserved for the power receiving unit, thereby increasing the power that can be drawn by other power transmission units sharing the same power source.

[0064] If the response to the power receiving device's request indicates that the power receiving device does not agree to transition to power-saving mode (a "NO" branch in block 830), the power transmitting device may wait for a predetermined time (block 834), return to block 826, and repeat the request to transition to power-saving mode. For example, the power receiving device may be experiencing a transient fault condition such as overtemperature, overvoltage, overcurrent, or other transient event. The power receiving device may wait for the transient fault to resolve and then request the power transmitting device to re-enter the power-receiving state. In another example, the power receiving device may be waiting for user input. After receiving user input, the power receiving device may request the power transmitting device to transition to the power-receiving state. In this case of waiting for user input, if the waiting time is longer than a threshold, the power receiving device may send a response (received by the power transmitting device in block 828) indicating that the power receiving device agrees to the power transmitting device transitioning to the standby state in block 832.

[0065] During the process of repeatedly requesting a transition to power-saving mode, the power transmission and receiving devices maintain their connection state, allowing communication between them to continue. Furthermore, once the fault is resolved, the power transmission and receiving devices can resume transmitting and receiving power without entering a reinitialization state, thus saving time and resources.

[0066] Figure 8C is a flowchart 840 illustrating exemplary operation for interpreting a receiving device status indicator while the transmitting device is in a transmitting / receiving state. The transmitting device can receive a communication message from the receiving device (block 844). The communication message may include a status field indicating the status of the receiving device. The status field may include multiple indicators of the receiving device's status. In the example shown in Figure 8C, a first indicator indicates that the receiving device no longer wishes to receive power from the transmitting device. A second indicator may indicate that there are no communication errors between the transmitting and receiving devices. An indicator indicating that the receiving device is not receiving power from the transmitting device may indicate that the receiving device is experiencing a fault or other condition that is preventing the receiving device from operating.

[0067] After the power receiving device receives a message from the power receiving device indicating that it should not be supplied with power, the power transmitting device can stop supplying power to the power receiving device and enter a connected state (block 846). In some embodiments, the power transmitting device stops supplying power to the power receiving device within 20 ms of receiving the communication message.

[0068] The power transmission unit can send a message to the power receiving unit requesting a transition to power-saving mode (block 848). In some implementations, such as those conforming to the Ki Cordless Kitchen Wireless Power Specification, the power transmission unit can request a transition to standby mode by sending a "NEXT / stb" message to the power receiving unit.

[0069] The power transmission unit can determine whether or not to receive a response to a message requesting a transition to a power-saving mode (determination block 850). For example, the power transmission unit may request a transition to a standby state. If the power transmission unit does not receive a response to the request (branch "NO" in block 850), the power transmission unit can enter a standby state (block 854). The power transmission unit may also release power reserved for the power receiving unit to a common pool available to other power transmission units, i.e., power transmission units that share a common power source.

[0070] If the power transmission unit receives a response to the request (the "YES" branch in block 850), the power transmission unit can determine whether the response to the power receiving unit's request indicates that the power receiving unit agrees to transition to power-saving mode (block 852). If the power receiving unit indicates that it agrees to transition to power-saving mode (the "YES" branch in block 852), the power transmission unit enters a standby state (block 854).

[0071] If the response to the power receiving device's request indicates that the power receiving device does not agree to transition to power-saving mode (a "NO" branch in block 852), the power transmitting device can wait for a predetermined time (block 856), return to block 826, and repeat the request to transition to power-saving mode. For example, the power receiving device may be experiencing a transient fault condition such as overtemperature, overvoltage, overcurrent, or other transient event. The power receiving device can wait for the transient fault to resolve and then request the power transmitting device to re-enter the power-receiving state. In another example, the power receiving device may be waiting for user action to resolve the fault. After receiving user input, the power receiving device can request the power transmitting device to transition to the power-receiving state.

[0072] During the process of repeatedly requesting a transition to power-saving mode, the power transmission and receiving devices maintain their connection state, allowing communication between them to continue. Furthermore, once the fault is resolved, the power transmission and receiving devices can resume transmitting and receiving power without entering a reinitialization state, thus saving time and resources.

[0073] Figure 8D is a flowchart 860 illustrating an example of how the transmitting unit interprets the receiving unit status indicator when the receiving unit is experiencing a communication error. In some implementations, the transmitting and receiving units can be either connected or transmitting / receiving. The transmitting unit can receive a communication message from the receiving unit (block 862). The communication message may include a status field indicating the status of the receiving unit. The status field may include multiple indicators of the receiving unit's status. In the example shown in Figure 8D, a first indicator indicates that the receiving unit no longer wishes to receive power from the transmitting unit. A second indicator may indicate a communication error between the transmitting and receiving units.

[0074] In this example, the receiving device uses a first indicator and a second indicator to indicate that the receiving device is experiencing a persistent communication error. The transmitting device can enter a reinitialization state (block 864). Entering a reinitialization state is advantageous because it can free up power resources associated with the receiving device experiencing the persistent communication error, making them available to other receiving devices. In some embodiments, the receiving device may detect a persistent communication error based on a number of unsuccessful communication attempts exceeding a predetermined or configurable threshold. For example, the receiving device may detect a persistent communication error after five unsuccessful communication attempts. In some embodiments, the receiving device may detect a persistent communication error if the receiving device fails to successfully attempt to communicate after a predetermined or configurable threshold time. For example, the receiving device may detect a persistent communication error if a communication attempt fails after 100 ms. In some embodiments, the transmitting device monitors the status field of the communication message from the receiving device and checks the status field for a second indicator indicating a communication error. If the error persists for a threshold period, the transmission unit will cut off power to the receiving unit (if in a transmission / reception state) and return the entire system to a reinitialization state. The transmission unit may do this without waiting for the receiving unit to set a first indicator indicating the power cutoff.

[0075] Figure 9A is a flowchart 900 illustrating exemplary operation for setting the power receiving device status indicator by the power receiving device. The power receiving device can determine its current operating condition (block 902). For example, the power receiving device can determine whether or not there is any fault in its operation. This is the case when the power receiving device is a hybrid power receiving device that can receive power via wireless power transfer or a wired power supply (e.g., mains power).

[0076] The power receiving device can set a first indicator and a second indicator in the status field of the communication message based on the current operating condition of the power receiving device. The first indicator indicates whether the power receiving device can receive power from the power transmitting device, and the second indicator indicates whether a communication error has occurred (block 904).

[0077] The power receiving device can provide communication messages to the power transmitting device (block 906).

[0078] The power receiving device may receive a message from the power transmitting device requesting a transition to power saving mode if the power receiving device sets a first indicator indicating that the power receiving device cannot receive power from the power transmitting device and a second indicator indicating that no communication error has occurred (block 908).

[0079] Figure 9B is a flowchart 920 illustrating an example of operation in which the power receiving device sets a power receiving device status indicator while the power receiving device is connected or transmitting / receiving power. The power receiving device can detect if there are conditions in the operation of the power receiving device that prevent power transfer from the power transmitting device to the power receiving device (block 922). For example, a fault in the operation of the power receiving device may prevent power transfer. The power receiving device may be a hybrid power receiving device that can receive power via wireless power transfer and via a wired power supply (e.g., mains power supply). When receiving power via a wired power supply, the power receiving device may prevent wireless power transfer from the power transmitting device.

[0080] The receiving device may send a communication message to the transmitting device having a status field with an indicator set to show that there is a condition preventing power transfer to the receiving device (block 924). For example, the receiving device may set a first indicator and a second indicator in the status field of the communication message, the first indicator indicating whether the receiving device can receive power from the transmitting device, and the second indicator indicating whether a communication error has occurred.

[0081] The power receiving device can determine its current state (block 926). If the power receiving device is in a connected state (branch of "connected" in block 926), the power receiving device can wait for the condition to be cleared.

[0082] If the condition is not cleared, the receiving device may receive a message from the transmitting device requesting a transition to power-saving mode. For example, in an implementation compliant with the Ki Cordless Kitchen Wireless Power Specification, the transmitting device may send a "NEXT / stb" message to the receiving device. In some embodiments, the receiving device itself may send a message to transition to power-saving mode (not shown in the flowchart).

[0083] If the receiving device sets a first indicator indicating that it cannot receive power from the transmitting device, and a second indicator indicating that no communication error has occurred, the transmitting device may send a message to the receiving device requesting a transition to power-saving mode. The receiving device can check whether such a request has been received from the transmitting device (block 932). If the receiving device has received a message requesting a transition to power-saving mode (the "YES" branch in block 932), the receiving device can respond to the request to transition to power-saving mode (block 940). If the response in block 940 indicates that the receiving device agrees to transition to power-saving mode (the "YES" branch in block 942), the receiving device can enter power-saving mode (block 944). For example, the receiving device can enter a standby state. If the response in block 940 indicates that the receiving device does not agree to transition to power-saving mode (branch "NO" in block 942), the method returns to block 924 to send a subsequent message to the transmitting device in which a first indicator is set to indicate that the receiving device cannot receive power from the transmitting device, and a second indicator is set to indicate that no communication error has occurred.

[0084] If the power receiving device has not received a request to transition to power-saving mode (branch "NO" in block 932), the power receiving device can return to block 924 and send a subsequent message to the power transmitting device. As already mentioned, although not shown in the flowchart, in some cases the power receiving device itself can send a message requesting a transition to power-saving mode.

[0085] If the power receiving device is in a power transmission / reception state (branch of "power transmission / reception" in block 926), the power receiving device may wait for a period of T1 (block 934). In some implementations, T1 may be in the range of 5ms to 30ms, for example, 20ms.

[0086] Subsequently, the power receiving device can enter a connected state because the power transmitting device stops power transfer within the T1 period (block 936).

[0087] In some embodiments, the power receiving device opens the electrical connection between the power receiving device and its load (e.g., battery). For example, the power receiving device may wait until period T2 (block 937) and open the safety relay at the end of period T2 (block 938). The power receiving device may open the safety relay during period T2 if power transfer from the power transmitting device has stopped. In some implementations, T2 can be in the range of 25ms to 60ms, for example, 40ms.

[0088] The power transmission unit may send a message to the power receiving unit requesting a transition to power-saving mode. The power receiving unit can check whether such a request has been received from the power transmission unit (block 939). If the power receiving unit has received a message requesting a transition to power-saving mode (branch "YES" in block 939), the power receiving unit can transition to power-saving mode as requested (block 940). If the power receiving unit has not received a message requesting a transition to power-saving mode (branch "NO" in block 939), the method returns to block 924 and sends a subsequent message to the power transmission unit. Although not shown in the flowchart, in some cases the power receiving unit itself may send a message requesting a transition to power-saving mode.

[0089] If the response in block 940 indicates that the power receiving device agrees to transition to power-saving mode (branch to "YES" in block 942), the power receiving device can enter power-saving mode (block 944). For example, the power receiving device can enter standby mode. If the response in block 940 indicates that the power receiving device does not agree to transition to power-saving mode (branch to "NO" in block 942), the method returns to block 924 and sends a subsequent message to the power transmitting device.

[0090] In some implementations, at any point in the process shown in Figure 9B, the receiving device can determine whether conditions still exist that would prevent it from receiving power from the transmitting device. For example, overtemperature, overvoltage, overcurrent, or other potentially transient conditions may no longer exist. In another example, the hybrid receiving device may be disconnected from the wired power supply, thereby enabling wireless power transfer. Once the conditions preventing wireless power transfer are cleared, the receiving device can request that the transmitting and receiving devices enter a transmitting / receiving state.

[0091] Figure 9C is a flowchart 960 illustrating exemplary operation in which the power receiving device sets a power receiving device status indicator when the power receiving device is experiencing a persistent communication error. In some implementations, the operation shown in Figure 9C may be performed when the power receiving device is in a connected or transmitting / receiving state. The power receiving device can detect that there is a persistent communication error in the power receiving device (block 962).

[0092] The receiving device can send a communication message to the transmitting device having a status field with an indicator set to show that there is a condition preventing power transfer to the receiving device, indicating that the receiving device is experiencing a persistent communication error (block 964). For example, the receiving device can set a first indicator in the status field of a communication message to show that the receiving device is not receiving power from the transmitting device, and a second indicator in the status field to show that the receiving device is experiencing a persistent communication error. The two indicators, upon receiving a message having a status field with both indicators set, can cause the transmitting device to reinitialize. As described above, in some cases, the transmitting device can monitor the communication error status indicator and, if the indicator remains set for longer than a threshold time, can shut off power (if in a power-sending / receiving state) and transition the system to a reinitialization state without waiting for the first indicator to be set to show that the receiving device is unable to receive power.

[0093] Figures 10–13 are timing diagrams illustrating various state transitions that may occur during the operation of a wireless power transmission system, including power transmission devices (e.g., power transmission devices 102, 300) and power receiving devices (e.g., power receiving devices 118, 400). In the examples shown in Figures 10–13, the x-axis 10–10 represents time. The illustrative timing diagrams in Figures 10–13 are explained in the context of the Ki Cordless Kitchen Wireless Power Specification. However, the techniques described herein are readily applicable to other wireless power transfer specifications.

[0094] Figure 10 is a timing diagram 1000 illustrating a first example of state transitions in a wireless power system. The timing diagram 1000 shown in Figure 10 illustrates an exemplary state transition in a wireless power system, assuming no faults in the power receiving device that could prevent the power receiving device from entering a transmitting / receiving state. In the example in Figure 10, the timing diagram 1000 begins in a discovery state (also called the “discovery phase”) at time T0. The discovery state continues from T0 to T1. While the power receiving and transmitting devices are in the discovery state, a user may place an electrical appliance (e.g., a power receiving device) near the power receiving device. The power receiving device detects that an object has been placed near it and attempts to read NDEF data from the object using NFC technology. As described above, the NDEF data can identify the object (e.g., an electrical appliance) as a power receiving device eligible to receive power from the power receiving device.

[0095] After the transmission unit recognizes the receiving unit, the transmission and receiving units transition to a connected state (also called the "connection phase"). The connected state lasts from T1 to T2. In the connected state, the transmission and receiving units negotiate various transmission parameters, including guaranteed power. The transmission and receiving units may exchange messages as part of the power negotiation process. In the example shown in Figure 10, there are no faults occurring in the receiving unit, and therefore the PSTP and COMM_ERR bits are not set in the receiving unit status field. During the connected state, the user may turn on electrical appliances. The receiving unit can send a "NEXT / pow" message to the transmission unit instructing it to transition to a transmit / receive state (also called the transmit / receive phase). The transmission unit can also obtain the status of the receiving unit. Similarly, since there are no faults, the PSTP and COMM_ERR bits in the status field remain clear.

[0096] The power transmission / reception state continues from T2 onward. During this state, power is wirelessly transferred from the power transmission device to the power reception device. Power during the power transmission / reception state can be managed using the "ctrl" message.

[0097] Figure 11 is a timing diagram 1100 illustrating a second example of state transitions in a wireless power system. The timing diagram 1100 shown in Figure 11 illustrates an exemplary state transition that occurs in a wireless power system when a failure in the receiving device prevents the receiving device from transitioning from a connected state to a transmitting / receiving state. In the example in Figure 11, the timing diagram 1100 begins at time T0, when the transmitting device (and receiving device) is in a standby state (also called the “standby phase”). The standby state continues from T0 to T1. In some cases, the receiving device may not be present on the interface surface, and the system may enter the discovery phase when the receiving device is placed on the interface surface, as shown in Figure 11.

[0098] The detection state continues from T1 to T2. The power transmission device detects that an object has been placed in its vicinity and attempts to read NDEF data from the object using NFC technology. As described above, the NDEF data can identify the object (e.g., an electrical appliance) as a power receiving device that is qualified to receive power from the power transmission device.

[0099] After the power transmission unit recognizes the power receiving unit, the power transmission unit and the power receiving unit transition to a connected state (also called the "connection phase"). The connected state lasts from T2 to T8. At the start of the connected state, i.e., near T2, the power transmission unit and the power receiving unit negotiate, and the power transmission unit reserves negotiated power from the AC power source for the power receiving unit. This is not shown in Figure 11. In the example shown in Figure 11, at T3, a fault or status change occurs. As a result of the fault, the power receiving unit indicates that a power outage is necessary, i.e., the power transmission unit should not begin transmitting power signals to the power receiving unit. The power receiving unit sets the PSTP bit to 1 to indicate the power outage request and clears the COMM_ERR bit to indicate that there is no communication error. At time T4, the power transmission unit receives a message from the power receiving unit with the PSTP bit set in the power receiving unit status field of the message. At time T5, the power transmission unit sends a "NEXT / stb" message to the power receiving unit requesting whether the power transmission unit can enter a standby state. The receiving device receives the NEXT / stb message and, at time T6, acknowledges the message, indicating that it agrees to transition to the standby state. At time T7, the transmitting device receives the acknowledgment and transitions to the standby state. The transmitting device can release the negotiated power reserved for the receiving device. Although not shown in Figure 11, if the operating state is the transmit / receive state rather than the connected state shown in Figure 11, the receiving device may initiate a power outage by setting the PSTP bit in the status when it detects a fault. This may cause the transmitting device to stop supplying power to the receiving device and transition to the connected state. After this transition to the connected state, the protocols of the transmitting and receiving devices follow the protocols from time T5 to time T8 in Figure 11. In other words, the transmitting device can issue a Next / stb to the receiving device to request whether it can transition to the connected state, and if the receiving device accepts this, it acknowledges the request at T6 and the system transitions to the standby state at T7.

[0100] Figure 12 is a timing diagram 1200 illustrating a third example of a state transition in a wireless power system. The timing diagram 1200 shown in Figure 12 illustrates an exemplary state transition that occurs in a wireless power system when a fault in the receiving device prevents a transition between the transmitting and receiving states. In the example in Figure 12, when a fault is notified, the transmitting device issues a request to the receiving device to enter a power-saving mode. In this example, the receiving device responds to the request with "No".

[0101] In the example in Figure 12, timing diagram 1200 starts from time T0, when the power transmission device is in a standby state. The standby state continues from T0 to T1.

[0102] The detection state continues from T1 to T2, when the user places an electrical appliance (e.g., a power receiving device) near the power transmission device. The power transmission device detects that an object has been placed near it and attempts to read NDEF data from the object using NFC technology. As described above, the NDEF data can identify the object (e.g., an electrical appliance) as a power receiving device that is qualified to receive power from the power transmission device.

[0103] After the power transmission unit recognizes the power receiving unit, the power transmission unit and the power receiving unit transition to a connected state (also called the "connection phase"). The connected state lasts from T2 to T8. At the start of the connected state, i.e., near T2, the power transmission unit and the power receiving unit negotiate, and the power transmission unit reserves negotiated power from the AC mains for the power receiving unit. This is not shown in Figure 12. In the example shown in Figure 12, a fault occurs at T3. As a result of the fault, the power receiving unit indicates that a power outage is required. The power receiving unit indicates that there is no communication error by setting the PSTP bit to 1 to indicate a power outage request and clearing the COMM_ERR bit. At time T4, the power transmission unit receives a message from the power receiving unit with the PSTP bit set in the power receiving unit status field of the message. At time T5, the power transmission unit sends a "NEXT / stb" message to the power receiving unit indicating that the power receiving unit should enter a standby state. In this example, the receiving device receives a NEXT / stb message and, at time T6, replies with a message (NOK or "NOT OKAY" message) indicating that it will not transition to the standby state. At time T7, the transmitting device receives a NOK message from the receiving device and waits for action from the receiving device. For example, the transmitting device may wait for a temporary fault to be resolved, for the receiving device to be disconnected from the wired power supply, or for user action on the receiving device. The transmitting device may periodically repeat the NEXT / stb message, and once a NOK message is received from the receiving device, the transmitting device can continue to wait for action from the receiving device. If the transmitting device receives an ACK or fails to receive a response, the transmitting device can enter the standby state. Although not shown in Figure 12, if the operating state is the transmit / receive state rather than the connection state shown in Figure 12, the receiving device can initiate a power shutdown by setting the PSTP bit in the status if it detects a fault. This causes the transmitting device to stop supplying power to the receiving device and move to the connection phase.After this transition to the connection phase, the protocols of the transmitting and / or receiving devices follow the protocol from time T5 to T8 in Figure 12, i.e., the transmitting device can issue a Next / stb command to request the receiving device to transition to the connection state. If the receiving device rejects the request, it can reject the request at T6. For example, the receiving device can send "not ok" (NOK) at T6. In some cases, if the transmitting device waits for a threshold time with the receiving device rejecting the request to transition to standby mode, the transmitting device may voluntarily enter standby mode without waiting for permission from the receiving device.

[0104] Figure 13 is a timing diagram 1300 illustrating a fourth example of state transitions in a wireless power system. The timing diagram 1300 shown in Figure 13 illustrates an example of state transitions in a wireless power system where a power receiving device detects a persistent communication error. The x-axis 1310 does not necessarily have to be on the same time scale as the x-axis 1010.

[0105] In the example in Figure 13, timing diagram 1300 begins at time T0, when the power transmission and receiving equipment are in a standby state. The standby state continues from T0 to T1.

[0106] The detection state continues from T1 to T2, when the user places an electrical appliance (e.g., a power receiving device) near the power transmission device. The power transmission device detects that an object has been placed near it and attempts to read NDEF data from the object using NFC technology. As described above, the NDEF data can identify the object (e.g., an electrical appliance) as a power receiving device that is qualified to receive power from the power transmission device.

[0107] After the power transmission unit recognizes the power receiving unit, at time T2, the power transmission unit and power receiving unit transition to a connected state (also called the "connection phase"). The power transmission unit and power receiving unit negotiate power at the start of the connection phase, i.e., close to T2 (not shown in Figure 13). In the example shown in Figure 13, the power receiving unit detects a persistent communication error. As a result of the communication error, the power receiving unit indicates that a power outage is required. The power receiving unit sets the PSTP bit to 1 to indicate a power outage request and also sets the COMM_ERR bit to indicate a persistent communication error. At time T4, the power transmission unit receives a message from the power receiving unit with the PSTP bit and COMM_ERR bit set in the power receiving unit status field of the message. In some embodiments, the power transmission unit waits for 20ms, and at time T5, the power transmission unit transitions to a reinitialization state. Following the reinitialization procedure from time Tx to time T(x+1), the power transmission unit may transition to a discovered state. The power receiving unit is also reinitialized and transitions to a discovered state. In some embodiments, during reinitialization, the power transmission device releases the power reserved for the power receiving device.

[0108] Figure 14 shows a block diagram of an example device used in a wireless power system. In some implementations, device 1400 may be a power transmission device as described herein (e.g., power transmission device 102). In some implementations, device 1400 may be an example of either power transmission device 102 or 300, or one of the power control units 108 described with reference to any figure herein. Device 1400 may include a processor 1402 (which may have multiple processors, multiple cores, multiple nodes, or implement multithreading). Device 1400 may also include memory 1406. Memory 1406 may be system memory or any one or more of the possible realizations of computer-readable media as described herein. Device 1400 may also include a bus 1411 (PCI, ISA, PCI-Express, HyperTransport®, InfiniBand®, NuBus®, AHB, AXI, etc.).

[0109] The device 1400 may include one or more control units 1462 configured to manage a plurality of primary or secondary coils (e.g., a coil array 1464). In some implementations, the control units 1462 may be distributed within the processor 1402, memory 1406, and bus 1411. The control units 1462 may perform some or all of the operations described herein. For example, the control unit 1462 may be one of the transmit control units described herein.

[0110] Memory 1406 may contain computer instructions executable by processor 1402 for implementing the functions or techniques of the embodiments described with reference to Figures 1-7, 8A-8C, 9A, 9B, and 10-12. Any one of these functions may be partially (or completely) implemented in hardware, or partially (or completely) implemented on processor 1402. For example, the function may be implemented in an application-specific integrated circuit, in logic implemented on processor 1402, or in a coprocessor on a peripheral device or card. Furthermore, the implementation may involve fewer components or include additional components not shown in Figure 14. Processor 1402, memory 1406, and control unit 1462 may be coupled to bus 1411. Although illustrated as being connected to bus 1411, memory 1406 may be connected to processor 1402.

[0111] The operations described in Figures 1–14 and in the text are examples intended to aid in understanding exemplary implementations and should not be used to limit potential embodiments or the scope of claims. Some implementations may involve additional operations, fewer operations, parallel operations or operations in different orders, and some operations may be performed in other ways.

[0112] The above discussion is presented in the context of a power receiving device status field having a first indicator and a second indicator that can be combined as indicators indicating that the power receiving device is able to receive power from the power transmitting device. However, these techniques can easily be applied to separate bits that serve as indicators indicating that the power receiving device is able to receive power from the power transmitting device. For example, instead of the PSTP bit and the COMM_ERR bit, a “Power Receiving” bit in the power receiving device status may be used. Furthermore, the techniques described herein can be applied using other combinations of bits in the power receiving device status field.

[0113] Furthermore, the above discussion is presented in the context of wireless power systems in a wireless kitchen environment. However, the technologies disclosed herein are readily applicable to other environments. For example, the technologies discussed herein can generally be applied to light electric vehicles (EVs), including vehicles with batteries of less than 5 kWh and engine output of less than 10 kW. Examples of such vehicles include micromobility vehicles such as electric bicycles and electric kick scooters, electric two-wheeled or three-wheeled vehicles (ePTWs) such as e-mopeds, e-scooters, and e-rickshaws, electric microcars, low-speed electric vehicles, neighborhood electric vehicles (NEVs), micro-EVs such as electric four-wheeled vehicles, electric forklifts, and electric transport vehicles such as electric golf carts equipped with batteries of less than 120V.

[0114] Other environments include automated guided vehicles (AGVs), commercial drones, yard equipment such as electric lawnmowers, and large household appliances such as vacuum cleaners.

[0115] The above disclosure provides explanations and illustrations, but is not intended to be exhaustive or to limit to the exact form disclosed. Modifications and variations may be made in light of the above disclosure or obtained by implementing this disclosure. While the aspects of this disclosure are described in relation to various examples, any combination of aspects from any of the examples is also within the scope of this disclosure. The examples of this disclosure are provided for educational purposes. Alternatively, or in addition to other examples described herein, any combination of the following implementation options (listed as sections for clarity) is included as examples.

[0116] Article 1. A method for a power transmitter (PTx) in a wireless power system, comprising: receiving a communication message from a power receiver (PRx) in the wireless power system, the PRx including a status field indicating the status of the power receiver; and controlling state transitions based on a first indicator of the status field indicating whether the power receiver can receive power from the power transmitter and a second indicator of the status field indicating whether a communication error has occurred.

[0117] Article 2. The method of the first clause, further comprising the power transmission device providing the power receiving device with a first message requesting the power receiving device to transition to a standby state, where the first indicator has a first value indicating that the power receiving device is unable to receive power from the power transmitting device, the second indicator has a second value indicating that no communication error has occurred, and the current state of the power transmitting device is connected.

[0118] Article 3. The method of the second clause, further comprising receiving a response from the power receiving device to the first message, and if the response indicates that the power receiving device agrees to the transition to the standby state, the power transmitting device transitions from the connected state to the standby state.

[0119] Article 4. The method of the second clause, further comprising the power transmission device transitioning from the connected state to the standby state if the power transmission device is unable to receive a response to the first message from the power receiving device.

[0120] Article 5. The method of the second clause, further comprising receiving a response from the power receiving device to the first message, wherein if the response from the power receiving device to the first message indicates that the power receiving device does not agree to transition to the standby state, the power transmitting device performs an operation including waiting for a predetermined time and the power transmitting device providing the power receiving device with a second message requesting the transition to the standby state.

[0121] Article 6. The method according to the first clause, wherein if the first indicator has a first value indicating that the power receiving device is unable to receive power from the power transmitting device, and the second indicator has a second value indicating that no communication error has occurred, and the current state of the power transmitting device is a power-sending / receiving state, the power transmitting device performs an operation comprising: terminating the power transfer by the power transmitting device to the power receiving device, the power transmitting device transitioning from the power-sending / receiving state to a connected state, and providing the power receiving device with a first message requesting a transition to a standby state.

[0122] Article 7. The method of the sixth clause, further comprising receiving a response from the power receiving device to the first message, and if the response indicates that the power receiving device agrees to transition to the standby state, the power transmitting device transitions from the connected state to the standby state.

[0123] Article 8. The method according to the sixth clause, further comprising the power transmission device transitioning from the power transmission / reception state to the standby state if the power transmission device is unable to receive a response to the first message from the power receiving device.

[0124] Article 9. The method of the sixth clause, further comprising receiving a response from the power receiving device to the first message, wherein if the response to the first message indicates that the power receiving device does not agree to transition to the standby state, the power transmitting device performs an operation including waiting for a predetermined time and providing the power receiving device with a second message requesting the transition to the standby state.

[0125] Article 10. The method according to any one of the first to ninth clauses, further comprising the power transmission device transitioning to a reinitialization state if the first indicator has a first value indicating that the power receiving device is unable to receive power from the power transmitting device, and the second indicator has a second value indicating that the communication error has occurred.

[0126] Article 11. A method for a power receiving device in a wireless power system, the method comprising: the power receiving device determining the current operating condition of the power receiving device; setting a first indicator and a second indicator in the status field of a communication message based on the current operating condition of the power receiving device, wherein the first indicator indicates whether the power receiving device can receive power from a power transmitting device, and the second indicator indicates whether a communication error has occurred; providing the communication message to the power transmitting device of the wireless power system; and receiving a message from the power transmitting device requesting a transition to a standby state when the first indicator has a first value indicating that the power receiving device cannot receive power from the power transmitting device, and the second indicator has a second value indicating that no communication error has occurred.

[0127] Article 12. The method of the 11th clause, wherein the current state of the power receiving device includes a connection state, the current operating condition of the power receiving device includes fault conditions that prevent the power receiving device from transitioning from the connection state to a power transmission / receiving state, and setting a first indicator and a second indicator of the status field based on the current operating condition of the power receiving device includes setting the first indicator to a first value indicating that the power receiving device is unable to receive power from the power transmission device, and setting the second indicator to a second value indicating that no communication error has occurred.

[0128] Article 13. The method of the 12th clause, further comprising, while the current operating condition indicates the fault condition, continuing to set the first indicator of the status field in one or more subsequent first communication messages transmitted to the power transmission device to a first value indicating that the power receiving device is unable to receive power from the power transmission device, and setting the first indicator of the status field and the second indicator of the status field in the communication messages based on the current operating condition of the power receiving device to a third value indicating that the power receiving device can receive power from the power transmission device when the current operating condition indicates that the fault condition has been resolved.

[0129] Article 14. The method of the 11th clause, wherein the power receiving device is capable of receiving power via a wired power supply and wireless power transmission from the power transmitting device, the current state of the power receiving device includes the connection state, and setting the first indicator and the second indicator of the status field based on the current operating condition of the power receiving device includes setting the first indicator to a first value indicating that the power receiving device is unable to receive power from the power transmitting device when the power receiving device is receiving power via the wired power supply, and setting the second indicator to a second value indicating that no communication error has occurred.

[0130] Article 15. The method according to the 14th clause, further comprising: keeping the first indicator of the status field in one or more subsequent first communication messages transmitted to the power transmission device set to a first value indicating that the power receiving device is unable to receive power from the power transmission device while the power receiving device is receiving power via the wired power supply; and setting the first indicator of the status field in one or more subsequent second communication messages transmitted to the power transmission device to a third value indicating that the power receiving device is able to receive power from the power transmission device when the power receiving device ceases to receive power via the wired power supply.

[0131] Article 16. The method of the 11th clause, wherein the current state of the power receiving device includes a power transmission / reception state, the current operating condition of the power receiving device includes a fault condition, and setting the first indicator and the second indicator of the status field based on the current operating condition of the power receiving device includes setting the first indicator to a first value indicating that the power receiving device is unable to receive power from the power transmitting device, and setting the second indicator to a second value indicating that no communication error has occurred.

[0132] Article 17. The method according to the 16th clause, further comprising transitioning from the power transmission / reception state to the connection state after a predetermined first time has elapsed.

[0133] Article 18. The method according to the 17th clause, further comprising opening the electrical connection from the power receiving device to the load after a predetermined second time has elapsed.

[0134] Article 19. The method according to Clause 18, wherein the predetermined first time includes a first time value within a first range including 5ms to 40ms, and the predetermined second time includes a second time value within a second range including 25ms to 60ms.

[0135] Article 20. The method according to any one of the 11th to 19th clauses, further comprising providing the power transmission device with a response to the message requesting a transition to the standby state.

[0136] Article 21. The method according to any one of the 11th to 20th paragraphs, wherein the current operating condition of the power receiving device includes a persistent communication error, and setting a first indicator and a second indicator of the status field based on the current operating condition of the power receiving device includes setting the first indicator to a value indicating that the power receiving device is unable to receive power from the power transmitting device, and setting the second indicator to a value indicating that a communication error has occurred, and the power transmitting device is configured to transition to a reinitialization state when the first indicator is set to the first value and the second indicator is set to the second value.

[0137] Article 22. A power transmission device comprising a control unit configured to perform any one of the methods described in the provisions 1 to 10.

[0138] Article 23. A power receiving device comprising a control unit configured to perform any one of the methods described in the provisions 11 to 21.

[0139] Other innovative aspects of the subject matter described herein can be implemented as a computer-readable medium storing instructions that cause the processor to perform any one of the methods or features described herein when executed by the processor.

[0140] Other innovative aspects of the subject matter described herein can be implemented as a system having means for carrying out any one of the methods or features described herein.

[0141] As used herein, the phrases “at least one” or “one or more” referring to list items refer to any combination of those items, including a single member. For example, “at least one of a, b, and c” is intended to include the possibilities of a only, b only, c only, a and b, a and c, b and c, and a, b, and c.

[0142] The various exemplary components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in relation to the embodiments disclosed herein may be implemented as electronic hardware, firmware, software, or a combination of hardware, firmware, and software, as well as including the structures disclosed herein and their structural equivalents. Hardware, firmware, and software compatibility is generally described in terms of functionality and is illustrated in the various exemplary components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the design constraints imposed on the particular application and the overall system.

[0143] Hardware and data processing devices used to implement the various exemplary components, logic, logic blocks, modules, and circuits described in part with respect to certain aspects of this disclosure may be implemented or run 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. A general-purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors used in conjunction with a DSP core, or any other such configuration. In some implementations, specific processes, operations, and methods may be performed by circuits specific to a given function.

[0144] As described 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 may include non-temporary processor-executable or computer-executable instructions encoded in one or more tangible processor-readable or computer-readable storage media, for execution by a data processing device including the components of the device described herein, or for controlling the operation of the data processing device. For example, these storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage media, magnetic disk storage media or other magnetic storage devices, or any other media that can be used to store program code in the form of instructions or data structures. Combinations of the above media should also be included within the scope of storage media.

[0145] Various modifications to the embodiments described herein will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of this disclosure. Accordingly, the claims are not intended to be limited to the embodiments shown herein, but should be given the widest scope consistent with this disclosure and the principles and novel features disclosed herein.

[0146] Furthermore, various features described herein in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately in multiple embodiments or in any suitable subcombination. Thus, features may be described as acting in a particular combination as described above, and may be initially claimed as such, but one or more features may be removed from the claimed combination, and the claimed combination may be directed towards subcombinations or variations of subcombinations.

[0147] Similarly, while the diagrams show operations in a specific order, this should not be understood as requiring that the operations be performed in the indicated order, or sequentially, or all indicated operations, in order to achieve the desired result. Furthermore, the diagrams may schematically illustrate one or more exemplary processes in the form of flowcharts or flow charts. However, other operations not illustrated may be incorporated into the schematically illustrated exemplary processes. For example, one or more additional operations may be performed before, after, concurrently with, or in between any of the illustrated operations. In some situations, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated into a single software product or packaged into multiple software products.

Claims

1. A method for a power transmission device (PTx) in a wireless power system, The receiving device (PRx) in the aforementioned wireless power system receives a communication message including an indicator that a communication error has occurred, To detect persistent communication errors based at least partially on the indicator, If the aforementioned persistent communication error occurs, the system will transition to a re-initialization state. Methods that include...

2. The indicator is set to indicate that a communication error has occurred when multiple unsuccessful communication attempts are detected. The method according to claim 1.

3. The aforementioned multiple unsuccessful communication attempts include five unsuccessful communication attempts. The method according to claim 2.

4. The detection of the aforementioned persistent communication error includes detecting the persistent communication error after a threshold number of communication errors have occurred. The method according to claim 1.

5. The indicator includes a first indicator included in the status field of the communication message, The status field further includes a second indicator indicating whether the power receiving device can receive power from the power transmitting device, The method further includes transitioning to the reinitialization state when the first indicator indicates that the communication error has occurred and the second indicator indicates that the power receiving device is unable to receive power from the power transmitting device. The method according to claim 1.

6. The indicator includes a first indicator included in the status field of the communication message, and the status field further includes a second indicator indicating whether the power receiving device can receive power from the power transmitting device. The method further includes the power transmission device providing the power receiving device with a first message requesting a transition to a standby state, provided that the first indicator is set to a first value indicating that the communication error has not occurred, the second indicator is set to a second value indicating that the power receiving device cannot receive power from the power transmission device, and the current state of the power transmission device is a connected state. The method according to any one of claims 1 to 4.

7. The transmission device further includes transitioning from the connected state to the standby state if the transmission device receives a response to the first message indicating that the power receiving device agrees to the transition to the standby state, or if the transmission device does not receive a response to the first message from the power receiving device. The method according to claim 6.

8. The power receiving device further includes receiving a response to the first message, If the response to the first message from the power receiving device indicates that the power receiving device does not agree to transition to the standby state, the power transmitting device shall Wait for the designated time, The power transmission device provides the power receiving device with a second message requesting a transition to the standby state, Perform an action that includes The method according to claim 6.

9. The indicator includes a first indicator included in the status field of the communication message, and the status field further includes a second indicator indicating whether the power receiving device can receive power from the power transmitting device. The method is as follows: If the first indicator has a first value indicating that the communication error has not occurred, the second indicator has a second value indicating that the power receiving device cannot receive power from the power transmitting device, and the current state of the power transmitting device is in a power transmission / receiving state, the power transmitting device The power transfer from the power transmission device to the power receiving device is terminated, The power transmission device transitions from the power transmission / reception state to the connection state, To provide the power receiving device with a first message requesting a transition to a standby state, Further including performing actions that include, The method according to any one of claims 1 to 4.

10. If the power transmission device receives a response from the power receiving device to the first message indicating that the power receiving device agrees to the transition to the standby state, or if the power transmission device cannot receive the response from the power receiving device to the first message, the power transmission device further includes transitioning from the connected state to the standby state. The method according to claim 9.

11. If the response to the first message indicates that the power receiving device does not agree to transition to the standby state, the power transmitting device, Wait for the designated time, To provide the power receiving device with a second message requesting a transition to a standby state, Further including performing actions that include, The method according to claim 9.

12. A method for a power receiving device in a wireless power system, The power receiving device determines the current operating condition of the power receiving device, Based on the current operating condition of the power receiving device, an indicator is set to show whether or not a communication error has occurred. To provide the power transmission device of the wireless power system with a communication message including the indicator, Includes, The indicator is configured to indicate that a communication error has occurred, in response to detecting that the current operating condition includes a persistent communication error. method.

13. Detecting that the current operating condition includes the persistent communication error includes detecting a threshold number of unsuccessful communication attempts. The method according to claim 12.

14. The indicator includes a first indicator included in the status field of the communication message, the status field further includes a second indicator indicating whether the power receiving device can receive power from the power transmitting device, and the method further includes setting the second indicator to indicate that the power receiving device cannot receive power from the power transmitting device in response to detecting that the current operating condition includes the persistent communication error. The method according to claim 12 or 13.

15. The indicator includes a first indicator included in the status field of the communication message, and the status field further includes a second indicator indicating whether the power receiving device can receive power from the power transmitting device. The method further includes receiving a message from the power transmission device requesting a transition to a standby state, provided that the status field of the communication message provided to the power transmission device includes a first indicator set to a first value indicating that no communication error has occurred, and a second indicator set to a second value indicating that the power receiving device is unable to receive power from the power transmission device. The method according to claim 12 or 13.

16. The current state of the power receiving device includes a connected state, the current operating condition of the power receiving device includes fault conditions that prevent the power receiving device from transitioning from the connected state to a power transmitting / receiving state, the indicator includes a first indicator, the first indicator is included in the status field of the communication message, the status field further includes a second indicator indicating whether the power receiving device can receive power from the power transmitting device, and setting the first indicator and the second indicator in the status field based on the current operating condition of the power receiving device is: This includes setting the first indicator to a first value indicating that the communication error has not occurred, and setting the second indicator to a second value indicating that the power receiving device cannot receive power from the power transmitting device. The method according to claim 12 or 13.

17. While the current operating condition includes the fault condition, the second indicator in the status field of one or more subsequent first communication messages transmitted to the power transmission device is kept set to the second value indicating that the power receiving device cannot receive power from the power transmission device. If the current operating condition indicates that the fault condition has been cleared, the second indicator in one or more subsequent second communication messages transmitted to the power transmission device is set to a third value indicating that the power receiving device can receive power from the power transmission device. The method according to claim 16.

18. The indicator includes a first indicator, the first indicator is included in the status field of the communication message, the status field further includes a second indicator indicating whether the power receiving device can receive power from the power transmitting device, the power receiving device can receive power via both a wired power supply and wireless power transmission from the power transmitting device, and the first indicator and the second indicator in the status field are set based on the current operating condition of the power receiving device. When the power receiving device is receiving power via the wired power supply, the second indicator is set to indicate that the power receiving device cannot receive power from the power transmitting device. The method according to claim 12 or 13.

19. While the power receiving device is receiving power from the wired power supply, the second indicator in the status field of one or more subsequent first communication messages transmitted to the power transmitting device is kept set to indicate that the power receiving device is unable to receive power from the power transmitting device. The further includes setting the second indicator in the status field of one or more subsequent second communication messages transmitted to the power transmission device to indicate that the power receiving device can receive power from the power transmission device when the power receiving device ceases to receive power via the wired power supply, The method according to claim 18.

20. The indicator includes a first indicator, the first indicator is included in the status field of the communication message, the status field further includes a second indicator indicating whether the power receiving device can receive power from the power transmitting device, the current state of the power receiving device includes the power transmitting / receiving state, the current operating condition of the power receiving device includes the fault condition, and setting the first indicator and the second indicator in the status field based on the current operating condition of the power receiving device is: This includes setting the first indicator to indicate that the aforementioned communication error has not occurred, and setting the second indicator to indicate that the power receiving device is unable to receive power from the power transmitting device. The method according to claim 12 or 13.

21. The further includes transitioning from the power transmission / reception state to the connection state after a predetermined first time has elapsed. The method according to claim 20.

22. The further includes disconnecting the electrical connection from the power receiving device to the load after a predetermined second time has elapsed. The method according to claim 21.

23. The predetermined first time has a first time value within a first range including 5 ms to 40 ms, and the predetermined second time has a second time value within a second range including 25 ms to 60 ms. The method according to claim 22.

24. If the current operating condition includes the persistent communication error, the second indicator is further set to a value indicating that the power receiving device cannot receive power from the power transmitting device. The method according to any one of claims 15 to 23.

25. A power transmission device comprising a control unit configured to perform any one of the methods described in claims 1 to 11.

26. A power receiving device comprising a control unit configured to perform any one of the methods described in claims 12 to 24.

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