Communication Protocols in Wireless Power Systems

Abstract

The present disclosure provides systems, methods, and apparatus for communication protocol enhancements in wireless power systems. Various embodiments relate generally to messages for communication protocols in wireless power systems. The communication protocols and related aspects address unexpected states of a power transmitter or receiver in a wireless power system.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates generally to wireless power. Some aspects of the present application relate to communications for power negotiation, power control, and fault handling in wireless power systems. [Background technology]

[0002] A wireless power system may include a power transmitter and a power receiver. For example, the power transmitter may be placed on or contained within a countertop or other flat surface. The power receiver may be contained in a cordless appliance such as a blender, kettle, air fryer, mixer, or toaster, among other examples. The power transmitter may include a primary coil that generates an electromagnetic field that can induce a voltage in a secondary coil of the power receiver when the secondary coil is placed in proximity to the primary coil. In this configuration, the electromagnetic field can wirelessly transfer power to the secondary coil. Power may be transferred using inductive or resonant coupling between the primary and secondary coils. The power receiver can provide the received power to operate the cordless appliance. Summary of the Invention

[0003] The systems, methods, and devices of the present disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0004] In one innovative aspect, the method may include setting a PTx minimum supported power level for the transmitter, the PTx minimum supported power level based on measurement and processing capabilities of the transmitter.

[0005] In one innovative aspect, the subject matter described in this disclosure can be implemented as a method. The method may include transferring power from a power transmitter to a power receiver during a power transfer phase after a first power negotiation. The method may also include receiving a power control message from the power receiver. The method may further include determining that the power control message indicates a requested power level that would cause the power transmitter to exceed a current or power limit of the power transmitter, or that the power transmitter cannot meet a guaranteed power established in the first power negotiation. The method may further include transitioning from the power transfer phase to a connection phase.

[0006] In one innovative aspect, the subject matter described in this disclosure can be implemented as a method. The method may include performing power negotiation with a power receiver during a connection phase. The method may also include receiving a negotiation value request message from the power receiver. The method may further include communicating a proposed negotiation value to the power receiver in response to the negotiation value request message.

[0007] In one innovative aspect, the subject matter described in this disclosure can be implemented as a method. The method may include obtaining a communication message from a power receiver, the communication message including a status field indicating a status of the power receiver.

[0008] In one innovative aspect, the subject matter described in this disclosure can be implemented as a method. The method may include transferring power to a receiver during a power transfer phase. The method may also include detecting a misalignment condition that causes the transmitter to operate beyond a PTx limit or prevents the transmitter from meeting guaranteed power at the PTx limit.

[0009] In one innovative aspect, the subject matter described in this disclosure can be implemented as a method, which may include adjusting a communication carrier level of a communication signal during a power transfer phase with a power receiver.

[0010] In one innovative aspect, the subject matter described in this disclosure can be implemented as a method. The method may include communicating a power control message to a power transmitter during a power transfer phase, the power control message indicating a requested power level. The method may also include determining that the power transmitter has transitioned from the power transfer phase to a connection phase due to the requested power level being less than the PTx minimum supported power level.

[0011] In one innovative aspect, the subject matter described in this disclosure can be implemented as a method. The method may include receiving power from a power transmitter during a power transfer phase after a first power negotiation. The method may also include communicating a power control message to the power transmitter. The method may further include receiving a phase transition message from the power transmitter indicating a requested power level that would cause the power transmitter to exceed a current or power limit of the power transmitter or indicating that the power transmitter cannot meet a guaranteed power established in the first power negotiation. The method may further include transitioning from the power transfer phase to a connection phase.

[0012] In one innovative aspect, the subject matter described in this disclosure can be implemented as a method. The method may include performing power negotiation with a power transmitter during a connection phase. The method may also include communicating a negotiation value request message to the power transmitter. The method may further include receiving proposed negotiation values ​​from the power transmitter in response to the negotiation value request message.

[0013] In one innovative aspect, the subject matter described in this disclosure can be implemented as a method. The method may include communicating a communication message to a power transmitter, the communication message including a status field indicating a status of the power receiver.

[0014] In one innovative aspect, the subject matter described in this disclosure can be implemented as a method. The method may include receiving a wireless power signal from a power transmitter during a power transfer phase. The method may also include communicating a control message or a phase transition message to the power transmitter. The method may further include determining that the power transmitter has not processed the control message or the phase transition message within an expected period of time. The method may further include initiating a mitigation technique associated with a communication failure in the wireless power system. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a block diagram of an example wireless power system including an example power transmitter and an example power receiver. [Figure 2] 1 illustrates a message flow diagram of an exemplary wireless power transfer process. [Figure 3] FIG. 1 is a block diagram conceptually illustrating an example power transmitter. [Figure 4] FIG. 1 is a block diagram conceptually illustrating an exemplary power receiver. [Figure 5] 1 shows a block diagram conceptually illustrating exemplary power negotiation and control. [Figure 6] FIG. 1 shows a block diagram conceptually illustrating a communication protocol. [Figure 7] 1 illustrates an exemplary message flow diagram conceptually illustrating exemplary communication enhancements. [Figure 8] 1 shows a message flow diagram conceptually illustrating an exemplary power negotiation. [Figure 9] 1 illustrates exemplary communication techniques for a power receiver to indicate status. [Figure 10] 1 shows a message flow diagram conceptually illustrating an exemplary communication technique for addressing misalignment during a power transfer phase. [Figure 11] 1 shows a diagram of the communication carrier voltage being regulated during the power transfer phase. [Figure 12]1 shows a message flow diagram conceptually illustrating an exemplary technique for dealing with communication failures during a power transfer phase. [Figure 13] 1 includes a flowchart of an example process of a power transmitter. [Figure 14] 1 includes a flowchart of an example process of a power transmitter. [Figure 15] 1 includes a flowchart of an example process of a power transmitter. [Figure 16] 1 includes a flowchart of an example process of a power transmitter. [Figure 17] 1 includes a flowchart of an example process of a power transmitter. [Figure 18] 1 includes a flowchart of an example process of a power transmitter. [Figure 19] 1 includes a flowchart of an exemplary process of a power receiver. [Figure 20] 1 includes a flowchart of an exemplary process of a power receiver. [Figure 21] 1 includes a flowchart of an exemplary process of a power receiver. [Figure 22] 1 includes a flowchart of an exemplary process of a power receiver. [Figure 23] 1 includes a flowchart of an exemplary process of a power receiver. [Figure 24] 1 is a block diagram of an exemplary apparatus for use in a wireless power system.

[0016] Please note that the relative dimensions of the drawings may not be drawn to scale. DETAILED DESCRIPTION OF THE INVENTION

[0017] The following description refers to particular implementations for purposes of illustrating innovative aspects of the present disclosure. However, those skilled in the art will readily recognize that the teachings herein can be applied in many different ways. The described implementations can be implemented in any means, device, system, or method for transmitting and receiving wireless power.

[0018] A wireless power system may include a power transmitter (also called a PTx or wireless power transmission device) that is integrated with or otherwise disposed on a surface. The wireless power system may also include a power receiver (also called a PRx or wireless power receiving device). The power transmitter may include a primary coil configured to wirelessly transmit power via a magnetic field to a secondary coil in the power receiver. In some implementations, the power transmitter may include a countertop-mounted primary coil or a primary coil embedded in or fabricated on a surface on which a cordless device can be placed. The cordless device may include a power receiver for wirelessly receiving power. The secondary coil of the receiver may obtain wireless energy from the magnetic field and provide it to a power receiving circuit. The power receiving circuit may convert the energy and utilize it to charge or power a load. The power receiver may be included in or integrated with a cordless device having a variable load (such as a blender, heating element, or fan, among other examples). In some implementations, the power receiver may be included in or integrated with a cordless device having a fixed load.

[0019] During the power transfer phase, the receiver may periodically communicate power control communications to the transmitter over the communication channel. The power control communications may indicate presence or status, among other examples. The power control communications may include a power request, a null communication (to indicate presence without feedback), or receiver feedback. The transmitter and receiver may communicate via near field communication (NFC), Bluetooth™, or other communication technologies.

[0020] The present disclosure provides systems, methods, and apparatus for power transmitters and power receivers to communicate. Various embodiments generally relate to messages for communication protocols in wireless power systems. In some aspects, the communication protocols may be defined by wireless power transfer standards. As wireless power transfer standards evolve, various message formats associated with previously defined communication protocols may be insufficient to support new functions and newly discovered fault conditions. In some aspects of the present disclosure, conventional message formats may be modified to implement new functions and features. Furthermore, some unexpected conditions of the power transmitter or power receiver may be addressed using communication signaling in wireless power systems.

[0021] In some aspects, the power transmitter may receive a control message (CTRL) indicating a requested power level (CTRL / rpl) that is below the minimum power level the power transmitter can support for the power transfer phase. When this occurs, in some implementations, the power transmitter can end the power transfer phase and transition to the connection phase. The power transmitter or the power receiver can initiate power negotiation during the connection phase to establish a new power contract. In some implementations, the power transmitter can inform the power receiver of its minimum supported power level.

[0022] In some aspects, the power transmitter may experience an unexpected problem that causes the power transmitter to exceed its current or power limits. For example, a sudden misalignment of the power receiver or a sudden undervoltage condition of the power transmitter may prevent the power transmitter from supplying the negotiated power level to the power receiver. In such cases, the power transmitter may terminate the power transfer phase and begin renegotiating the power contract with the power receiver.

[0023] During the connection phase, the power transmitter and the power receiver may negotiate a power contract. For example, the power transmitter and the power receiver may establish a guaranteed power level based on a power request from the power receiver and confirmation from the power transmitter that the power transmitter can reserve enough power to meet the guaranteed power level. The power transmitter may reserve a negotiated power, which includes the guaranteed power that the power transmitter can commit to delivering to the power receiver and the power transmitter's expected power transmission loss for providing the guaranteed power. In some cases, the power transmitter may determine during the connection phase negotiation that it does not have enough available power to accept the requested power level. If the power transmitter cannot accept the power contract, the power receiver may repeatedly send a new requested power level to negotiate a lower power contract. However, this process of negotiating a power contract may take multiple messages, cause delays, or result in a poor user experience. In some aspects of the present disclosure, the receiver may communicate requests to the transmitter, such that the transmitter indicates its available power or requests guaranteed power that the transmitter can meet. Thus, the communication protocol between the transmitter and receiver can improve power negotiation during the connection phase.

[0024] In some aspects, the power transmitter may be unable to process communications from the power receiver during the power transfer phase. For example, the power receiver may communicate a message (e.g., NEXT / con) requesting a transition from the power transfer phase to the connection phase. Alternatively or additionally, the power receiver may determine that the power transmitter is not transferring enough power to meet the requested power level (CTRL / rpl) and infer that the power transmitter is not processing communications from the power receiver. If the power receiver determines that the power transmitter is not responding to the NEXT / con or CTRL / rpl message, the power receiver may terminate power transfer and take steps to protect its load. For example, the power receiver may open a protection switch in its power receiver circuit. In some implementations, the power receiver may open the protection switch at the moment when the AC power voltage falls below a threshold (which is also the time when the wireless power signal has a voltage or current below a threshold level), such as during or near a communication slot. Opening the protection switch during or near the communication slot may prevent possible damage to the power receiver or power transmitter if the protection switch is opened with a high current. In some implementations, after opening the protection switch, the power receiver may collect basic operating power using the communication carrier during the communication slot. In some implementations, the power receiver may cause a user interface (UI) of the power receiver to indicate a communication failure and then power down with the protection switch open.

[0025] In some aspects, the power receiver may communicate status to the power transmitter during the connection phase or the power transfer phase. For example, the power receiver may indicate the status of its protection switch (open or closed), indicate whether line power is active (such that the power receiver is powered from an AC power source), indicate a fault condition, or indicate user activity, among other examples. In some implementations, the power receiver may indicate status in addition to traditional messages (such as measurement (MEAS) or request (RQST) messages). The status field included as part of the MEAS or RQST message may also function as a heartbeat or keep-alive presence indicator communicated by a separate message and communication overhead. In some implementations, status may be used in control architecture type 1 (passive near field communication (NFC)) to enable the power receiver to communicate its status to the power transmitter via a tag that the power transmitter reads during a communication slot.

[0026] In some aspects, the communication physical layer channel between the power transmitter and the power transmitter may be adapted based on changes to the alignment or other conditions. For example, during the power transfer phase, a conventional power transmitter may maintain the NFC carrier level at a constant carrier voltage level. However, the power receiver may change its position relative to the power transmitter, resulting in a change in the alignment between the power receiver and the power transmitter. When the alignment changes, the effectiveness (or fidelity) of communication may become unreliable unless the NFC physical layer channel is adapted. In some implementations, the power transmitter may determine a new coupling coefficient (indicative of the alignment between the power receiver and the power transmitter) and adjust the NFC carrier level during the power transfer phase to accommodate the change in the coupling coefficient.

[0027] In some aspects, the power transmitter may determine that it cannot meet the guaranteed power during the power transfer phase. The power transmitter may analyze the condition and determine that the reason the power transmitter cannot meet the guaranteed power is due to a change in alignment (specifically, misalignment) between the power receiver and the power transmitter. For example, if the power transmitter is not in an undervoltage condition and the power receiver is not reporting a PRx side fault condition, the power transmitter can check whether a misalignment has occurred. The power transmitter may initialize a coupling coefficient (k-factor) measurement to determine the current alignment. If the k-factor is outside of an acceptable range, the power transmitter may communicate a warning message to the power receiver to correct the alignment. Additionally or alternatively, the power transmitter may terminate power transfer and transition to the connection phase.

[0028] In some aspects, communication protocol messages may be modified to allow the power transmitter to notify the power receiver regarding a fault condition of the power transmitter. For example, the fault condition may be an over-temperature, over-current, or over-voltage error condition, among other examples. In some aspects, the communication protocols described herein may support the power receiver to communicate a message to the power transmitter to place the power transmitter in a standby state. In some aspects, communication protocol messages may be modified to allow communication of voltage and current information from the power receiver to the power transmitter, thereby enabling enhanced power control functions.

[0029] Particular implementations of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages: Power receivers and transmitters can support power negotiation, fault handling, and new features using the communication techniques described in this disclosure. The communication and fault handling techniques can prevent dangerous overvoltage or overcurrent conditions that might otherwise occur. Furthermore, the user experience is improved through better fault power negotiation, fault handling, and error recovery procedures enabled by the disclosed communication techniques.

[0030] Although the examples in this disclosure are based on wireless power used in kitchen systems, the technology is applicable to other types of systems. For example, the technology may be used with wireless power systems associated with home appliances, electronic devices, fans, space heaters, speaker systems, air compressors, garden equipment devices, or components of electric vehicles, among other examples.

[0031] FIG. 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 (also referred to as a "PTx") is a functional unit that converts electrical power into magnetic power. In this disclosure, the power transmitter 102 includes a PTx as well as a communication system and other electrical components. The power receiver (also referred to as a "PRx") is part of a wireless power transfer system that converts magnetic power into electrical power or heat. In this disclosure, the power receiver 118 includes a PRx as well as a communication system and other electrical components. The power transmitter 102 and the power receiver 118 may be separated by an interface space 190. In FIG. 1, dashed lines represent communication to distinguish them from solid lines representing electrical circuit lines. The power transmitter 102 includes a primary coil 104. The primary coil 104 may be a wired coil that transmits wireless power (also referred to as wireless energy). The primary coil 104 may transmit wireless energy using induction or magnetic resonance fields. The primary coil 104 may be associated with a transmitting circuit 110. The transmitting 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 capacitor 146 and the primary coil 104 are also referred to as a "tank circuit 147." The transmitting circuit 110 may also include other components (not shown) for impedance matching. The transmitter 102 may also include one or more sensors 152, such as a voltage sensor and a current sensor (not shown).

[0032] Some or all of the power transmitting circuitry 110 may be embodied as an integrated circuit (IC) that implements features of the present disclosure for controlling and transmitting wireless power to one or more receivers. The power controller 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.

[0033] The power supply 112 can provide power to the transmission circuitry 110 within the transmitter 102. The power supply 112 can convert alternating current (AC) power to direct current (DC) power. For example, the power supply 112 can include a converter that receives AC power from an external power source and converts the AC power to DC power used by the transmission circuitry 110.

[0034] The power controller 108 is connected to a first communication interface 114. The first communication interface 114 is connected to a first communication coil 116. In some implementations, the first communication interface 114 and the first communication coil 116 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). NFC is a technology that transfers data at a carrier frequency of 13.56 megahertz (MHz). The first communication unit 124 may also support any suitable communication protocol.

[0035] The power receiver 118 may include a secondary coil 120, a series capacitor 122, a series switch 123, a rectifier 126, an appliance controller 136, a second communication interface 132, a sensor 162, a load 130, and a memory (not shown). The capacitor 122 and the secondary coil 120 are also referred to as a "tank circuit 121." In some implementations, the power receiver 118 may also include a user interface (not shown) or other means for obtaining a load setting 164 indicating a desired operation of the load. In some implementations, the load setting 164 may be stored in a memory (not shown) of the power receiver 118. In some implementations, the load 130 may also include a driver (not shown) for controlling at least one parameter, such as the speed or torque, of the load. In some implementations, the rectifier 126 may be omitted. In some implementations, a series switch (not shown) may be included in series with the secondary coil 120. Although shown as separate components, some components may be packaged or implemented in the same hardware. For example, in some implementations, the appliance controller 136 and the power receiving controller (not shown) may be implemented as a single controller. The appliance controller 136, or any combination thereof, may be implemented as a microcontroller, a special purpose processor, an integrated circuit, an application specific integrated circuit (ASIC), or any other suitable electronic device.

[0036] The interface space 190 may define a spatial boundary between the power transmitter 102 and the power receiver 118. For example, the interface space may include a surface of the power transmitter 102 on which the power receiver 118 can be placed. The distance between the primary coil 104 and the secondary coil 120 may include the thickness of the surface within the interface space 190. During wireless power transfer, the primary coil 104 can induce a magnetic field (referred to as the primary magnetic field) through the interface space 190 into the operating environment in which the secondary coil 120 is placed. Thus, the "operating environment" is defined by the primary magnetic field within the system in which the primary magnetic field of the primary coil 104 detectably exists and can detectably interact with the secondary coil 120.

[0037] The power controller 108 can detect the presence or proximity of the power receiver 118. This detection may occur during a periodic ping process of the first communication interface 114 in the power transmitter 102. During the ping process, when the power receiver 118 is in proximity, the first communication interface 114 (via the first communication coil 116) may supply power to the second communication interface 132 (via the second communication coil 134). The second communication interface 132 may "wake up" and power up the appliance controller 136 and may send a response signal back to the first communication interface 114. The power transfer may be preceded by a handshake process during which the power controller 108 may receive, among other information, a data configuration related to the power rating of the power receiver.

[0038] Different cordless appliances may have different load types, different load states, and different power requirements, or may require power at specific voltages and frequencies. For example, a cordless blender may include a variable motor load with multiple user-selectable load states to control motor speed. Depending on the load state, the cordless blender may require different levels of power to operate. In another example, a cordless kettle may include a resistive load with different load states to control temperature. In yet another example, an air fryer may be a multi-load device and may operate a heater, a fan, or both during various operations. Each type of load (e.g., motor, resistive load, heater, fan, or any combination thereof) may require different amounts of power to operate based on the current load state or load condition. Furthermore, cordless appliances may exhibit different levels of voltage gain from the primary coil to the receiving coil at different primary coil excitation frequencies (e.g., wireless power transfer frequencies) depending on their load type or load state. For example, to achieve a desired load voltage, a cordless blender may operate best at a first operating frequency for a first load state, such as a low motor speed setting. However, as load conditions change, the cordless blender may not achieve the same load voltage when operated at the first operating frequency. For example, the first operating frequency may facilitate a first voltage gain when the cordless blender is set to a first load condition (e.g., a low-speed setting), and the first operating frequency 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 required power required for the load to operate at the load condition.

[0039] The power controller 108 can control characteristics of the wireless power that the power transmitter 102 provides to the power receiver 118. After detecting the power receiver 118, the power controller 108 can receive configuration data from the power receiver 118. For example, the power controller 108 can receive the configuration data during a handshake process with the power receiver 118. The power controller 108 can use the configuration data to determine at least one operating parameter (e.g., frequency, duty cycle, voltage, etc.) of the wireless power generated by the power transmitting circuit 110. The operating parameter may be adjusted based on feedback information from the power receiver 118 during the transfer of wireless power in response to changes in the load condition or power requirements of the load 130. Thus, the power controller 108 can provide wireless power that enables relatively efficient operation of the power receiver 118. For example, the transmission controller can configure the wireless power to enable the power receiver to operate at peak efficiency for a particular load condition, load voltage, and operating K factor.

[0040] A magnetic power source may refer to an appliance (e.g., a countertop or hob) that includes multiple power transmitters to provide wireless power to respective receivers. The transmitters in such a magnetic power source typically share a limited power source, such as a single wall outlet, and therefore typically cannot operate at full power simultaneously. Exceeding the rated power of the magnetic power source could trip a circuit breaker somewhere in the building, a highly undesirable situation. Such devices may use power negotiation to establish an agreed-upon amount of power that the transmitters reserve for specific receivers.

[0041] Power negotiation can ensure that devices, including the power receiver, can function as intended by reserving an amount of power for doing so. Prior to the power transfer phase, the power receiver can communicate a requested power negotiation value to the power transmitter. The requested power negotiation value represents the maximum power level the power receiver may require to operate its load. The requested power negotiation value is communicated prior to the power transfer phase. Therefore, the requested power negotiation value may be referred to as a requested power level, a power negotiation value (PRx-nego), or a pre-power requested power to distinguish it from a conventional power request (P-request) message (also called a request power message) that may be communicated during the power transfer phase to control power. The power transmitter can determine whether to accept or reject the requested power negotiation value based on the power available to the power transmitter. The available power refers to the maximum amount of power the power transmitter has available for wireless power transfer given the instantaneous ambient conditions. Ambient conditions include, among other things, the transmitter's input power and voltage, its temperature, and the receiver's magnetic coupling. In a magnetic power source with multiple transmitters, the ambient conditions may also include any other transmitter power usage or magnetic power source capabilities. For example, multiple transmitters can use the power negotiation techniques of this disclosure to reserve power from the available power provided by the magnetic power source.

[0042] The power transmitter can determine whether it can guarantee the requested power level (represented by the requested power negotiation value) based on the available power and the transmitter's estimated losses. For example, the power transmitter may estimate losses associated with its own components (such as its rectifier, inverter, coil, or filter components, among other examples) to supply the requested power level. If the available power is greater than the requested power negotiation value and the estimated losses, the power transmitter can accept the requested power negotiation value. Otherwise, the power transmitter may reject the requested power negotiation value or communicate an alternative power negotiation value for a power level lower than the requested power level. When the power transmitter accepts the requested power negotiation value, the power transmitter may set the requested power negotiation value as the guaranteed power to represent the power level that the power transmitter guarantees to be available for transmission to the power receiver. The transmitter may reserve a negotiated power (P-nego) from the available power to ensure that the transmitter has enough power to meet the guaranteed power. The negotiated power may be the sum of the guaranteed power and the estimated loss.

[0043] In some implementations, the power receiver can communicate a requested power negotiation value that takes into account the power rating of a load associated with the power receiver. The requested power negotiation value may also take into account power reception losses (PRx losses) associated with components of the power receiver. However, the requested power negotiation value may exclude power transmission losses (PTx losses) associated with components of the power transmitter, since those losses are estimated by the power transmitter.

[0044] In some implementations, the power transmitter can determine a working coupling coefficient (K factor) between the power transmitter and the power receiver. The working K factor refers to a K factor based on the actual alignment between the power receiver and the power transmitter. The power transmitter may adjust the PTx loss based on the K factor.

[0045] The power transmitter 102 and the power receiver 118 can implement a control architecture for managing the transfer of wireless power. The control architecture can define how power requirements are communicated and how the operating point of the power transmitter is controlled. In some implementations, the control architecture may be based on static power control (referred to as a “control type 1 architecture” or “Type 1”). In some implementations, the control architecture may be based on dynamic power control (referred to as a “control type 0 architecture” or “Type 0”). Devices implementing a control type 1 architecture may have a fixed load, may not include measurement circuitry, may not typically use auxiliary data transfer, and may require only minimal functionality to keep manufacturing costs down. A control type 1 architecture may rely on the control loop of the power transmitter 102 without feedback from the power receiver 118. Devices implementing a control type 0 architecture may have a static or dynamic load and may implement a controller for generating power request messages during power transfer, as well as measurement circuitry to appropriately control that load. This disclosure includes examples of both Type 0 and Type 1 control architectures as they relate to transitions between various operational phases.

[0046] In some implementations, the wireless communication interface 114 can communicate with the power receiver by transmitting a wireless communication signal and detecting changes in the wireless communication signal that indicate the communication of information. The wireless communication interface 114 may support the NFC Type 2 Tag specification or the NFC Type 4A Tag specification 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, intermodulation products of the two signals may cause interference that disrupts reliable NFC communication. To avoid this undesirable effect, the power signal may be periodically switched off for a short time interval. This time interval may be referred to as a communication time slot. Typically, the communication time slot may occur in conjunction with a zero-crossing event associated with the AC cycle of the AC mains power or wall outlet.

[0047] The wireless communication unit 132 may support the NFC Type 2 Tag specification or the NFC Type 4A Tag specification, as specified by the NFC specification. In some implementations, the wireless communication unit is configured to communicate with the power transmitter by storing information in a passive tag (such as an NFC Type 2 Tag) that can be read by a wireless communication interface of the power transmitter. Alternatively, the wireless communication unit may be configured to communicate with the power transmitter by transmitting information in a wireless communication signal to a wireless communication interface of the power transmitter (e.g., using an NFC Type 4A Tag).

[0048] FIG. 2 shows a message flow diagram of an exemplary wireless power transmission process. Referring to FIG. 2, the power transmitter 102 detects that the power receiver 118 is located in a charging area in standby mode (S200). There may be various methods for the power transmitter 102 to detect the power receiver 118, and the present disclosure is not limited to a specific method. As an example, the power transmitter 102 may detect that the power receiver 118 is located in the charging area by periodically emitting an analog ping of a specific frequency, and based on this detection current, a resonance shift or capacitance changes. As another example, the power transmitter 102 may periodically transmit a detection signal, and the power receiver 118 may transmit a response signal (e.g., a control error packet or a signal strength packet). The power transmitter 102 may detect that the power receiver 118 is located in the charging area based on receiving the response signal within a predetermined period following the detection signal. As yet another example, the power receiver 118 may transmit a search signal or an advertisement signal to the power transmitter 102. The search signal or advertising signal may be conventionally transmitted using short-range radio frequency communication (such as NFC or Bluetooth™). The power transmitter 102 may detect the power receiver 118 based on receiving the search signal or advertising signal.

[0049] In some implementations, as a preparatory step for wireless power transmission, the power transmitter 102 may optionally transmit an information request signal to the power receiver (S210). The information request signal may be a signal requesting an ID and requesting power information of the power receiver 118. As an 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 ping 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 optionally transmit its ID and configuration information to the power transmitter 102 (S220). For example, the configuration information may include a requested amount of power or a 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 the operation of the load. In some implementations, the configuration information may also include a time parameter. For example, the time parameter may indicate an expected time for the power receiver to complete an operation based on the rated power value. In some implementations, the information request signal and the ID and configuration information may be communicated using out-of-band communication (separate from the wireless power signal), such as NFC or Bluetooth.

[0050] Based on the ID and configuration information, the power transmitter 102 configures parameters for power transfer (called an operating point) and performs wireless power transfer to the power receiver 118 (S230). For example, the power transmitter may create a power transmission contract based on the ID and configuration information and control the wireless power transfer according to the power transmission contract. The process performed by the power transmitter 102 from the start to the end of wireless power transfer to the power receiver may be referred to as the (wireless) power transfer phase 235. In some implementations, the power receiver 118 may supply the received wireless power to an external load such as a heating element, a motor, or a battery, among other examples. In some implementations, the operation of the power receiver 118 may be based on the external load and user-configurable settings. For example, the operation may include boiling water, toasting bread, or cooking food. In other examples, the operation may be based on charging a battery or other energy storage device to a desired level.

[0051] The power transmitter 102 may monitor parameters for power transmission and may stop wireless power transmission if any one of the parameters exceeds a specified limit. Alternatively, the wireless power transmission process of S230 may be terminated at the request of the power receiver 118. For example, the power receiver 118 may transmit a signal to the power transmitter 102 requesting termination of wireless power transmission when the operation of the power receiver 118 is completed.

[0052] During the power transfer phase 235, the power receiver 118 periodically sends power control communications to the power transmitter 102 (shown at S240-1, S240-2, S240-3, and S240-4). Examples of power control communications may include control error packets (CEPs), power request messages, or status messages, among other examples, to control the amount of power transferred from the power transmitter 102 to the power receiver 118, i.e., to perform power control.

[0053] FIG. 3 shows a conceptual block diagram of an exemplary power transmitter 300. The power transmitter 300 may be an example of the power transmitter 102 described with reference to FIGS. 1 and 2, respectively. The power transmitter 300 may include a power source 302, which is shown as an AC power source. However, the power source 302 may be a DC power source or any other suitable power source. The power source 302 may be connected to a rectifier 304 (also referred to as a bridge rectifier or other related terminology). The rectifier 304 may be connected to a capacitor 306. The rectifier 304 may provide DC power to a first switch 316 and a second switch 318. The first switch 316 and the second switch 318 form an inverter 311 that generates an AC voltage from the DC power. The first switch 316 and the second switch 318 may be metal-oxide semiconductor field-effect transistors (MOSFETs) or insulated-gate bipolar transistors (IGBTs), among other examples. A first pulse-width modulation (PWM) driver 312 may be connected to the first switch 316, and a second PWM driver 314 may be connected to the second switch 318. The TX controller 108 may be connected to the first PWM driver 312 and the second PWM driver 314. The TX controller 108 can control the PWM drivers 312 and 314 to cause wireless power transmission according to a desired operating frequency, operating duty, or operating frequency, among other examples. The power transmitter 300 may include other components (such as a capacitor 320) in a path between the power source 302 and the primary coil 322. The rectifier 304, the capacitor 306, the inverter switches 316 and 318, and the capacitor 320 may collectively be referred to as a power transmitter (PTx) circuit 350. The TX controller 108 controls one or more components of the PTx circuit 350 to control the transmission of wireless power.

[0054] The TX controller 108 can exchange communications with the receiver via a communication unit. The communication unit may include a communication interface 326, a communication controller (not shown), or other components connected to the communication coil 328. In some implementations, the communication interface 326 and the communication coil 328 are configured to communicate using an NFC communication protocol. In some implementations, the communication interface 326 and the TX controller 108 may be co-located on a common processor or chip.

[0055] The TX controller 108 can detect a receiver in proximity to the primary coil 322 and perform a handshake process during which the TX controller 108 receives information from the receiver. The TX controller 108 can receive the information via the communication interface 326. In some implementations, the information may include one or more reference control parameters, such as the receiver's operating frequency at different reference coupling coefficients (K factors), the receiver's load voltage, and the receiver's load power. In some implementations, the information may indicate the load type and load status of a variable load associated with the receiver. The load status represents a combined state of the device's load voltage and corresponding load power. The TX controller 108 can use this information to provide wireless power with characteristics that enable the receiver to operate. For example, the TX controller 108 can provide wireless power by determining operating parameters and controlling first and second PWM drivers (312 and 314, respectively) based on the operating parameters. The PWM drivers (312 and 314, respectively) can operate a first switch 316 and a second switch 318. The first switch 316 and the second switch 318 may energize the primary coil 322 to transfer wireless power to the secondary coil of the power receiver according to the operating parameters.

[0056] FIG. 4 shows a block diagram conceptually illustrating an exemplary power receiver 400. The power receiver 400 may be an example of the power receiver 118 described with reference to FIGS. 1, 2, and 3. The power receiver 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, such as a battery) via a series switch (not shown). In some implementations, depending on the type of load 408 (such as a heating element), the rectifier 404, the capacitor 406, or both may not be present in the power receiver. The power receiver 400 may also include a communication unit 432. The power receiver 400 may also include a communication interface 426, which may include a second communication coil 428. The communication interface 426 may be connected to the receiver controller 424 .

[0057] The receiver controller 424 can receive various information and determine control error values, power requirements, or other feedback for communication to the transmitter via the communication unit 432. In FIG. 4 , dashed lines represent control or information lines to distinguish them from solid lines representing electrical circuit lines. The control or information lines may include electrical connections between the receiver controller 424 and other components of the receiver 400. In some implementations, the receiver controller 424 can receive information indicative of load settings, power requirements, or power estimates from a load controller (not shown) connected to the load 408. The receiver controller 424 can 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. However, the voltage sensor 414 may be missing or absent in some implementations of the example receiver 400.

[0058] The RX controller 424 can also communicate with the transmitter via the communication interface 426. In some implementations, the RX controller 424 can retrieve configuration data from a memory (not shown). The configuration data may be transmitted to the transmitter via the communication interface 426. The RX controller 424 may also retrieve information indicating a load status and / or a power estimate from a load controller (not shown) or a user interface (not shown). At various times before, during, or after the transfer of wireless power, the communication interface 426 may transmit the above-described configuration data, voltage measurement information, coupling information, power requirement information, load voltage information, and load status, among other examples, to the transmitter. The load settings may be user-selectable settings such as temperature settings, cooking times, or motor speed settings, among other examples. In some implementations, the configuration data may include a rated power value and a time parameter associated with the operation of the load 408. For example, the time parameter may indicate an expected time to boil water, bake bread, or cook food based on the load settings. In some cases, the RX controller 424 may send some or all of the configuration data to the transmit controller during a handshake process as described herein. In some cases, the RX controller 424 may send feedback information to the transmitter. The feedback information may include one or more of a load status, a reference voltage, a power estimate or request for the load, coupling coefficient information, load voltage information, a fault condition (if detected by the example receiver 400), or any combination thereof.

[0059] A TX controller (not shown) of the power transmitter may modify the wireless power being transmitted to the power receiver 400 based on the feedback information. The communication interface 426 may be configured to communicate messages to the power transmitter during predetermined communication slots. For example, the communication slots may be determined based on a synchronization unit (not shown), a clock, or other device. For example, the communication slots may occur when there is no switching in the power transmitter, and may be determined when the coil detection voltage (at the secondary coil 402) is zero.

[0060] FIG. 5 shows an example system state diagram 500 with an example power negotiation operation. System state diagram 500 consists of four major phases. When a user connects a power transmitter to utility power, the power transmitter enters an idle phase 510. During the idle phase 510, the power transmitter searches for the presence of a valid power receiver and, if detected, establishes communication. During the idle phase 510, the power transmitter waits until it detects an event that initiates object classification. If the object is a power receiver with a communication unit, the power transmitter initiates communication and then proceeds to a configuration phase 520. After the power receiver starts up, the power transmitter proceeds to a configuration phase 520 to receive static configuration data. System state diagram 500 also shows a connection phase 530 that follows the configuration phase 520 and precedes a power transfer phase 540. During the power transfer phase 540, power is transferred from the power transmitter to the power receiver.

[0061] During the configuration phase 520 or the connection phase 530, the power transmitter and receiver exchange information to agree on and coordinate parameters related to wireless power transfer or wireless charging. Power negotiation may occur during any of the phases prior to the power transfer phase 540. For example, power negotiation may occur during the connection phase 530. Power negotiation is used by the power transmitter and receiver to negotiate parameters governing the power transfer phase 540.

[0062] A brief description of power negotiation follows below. The power receiver can communicate a requested power negotiation value to the power transmitter. The requested power negotiation value may be based on the power rating of the load. In some implementations, the requested power negotiation value is based on a combination of the power rating of the load and the power reception loss (PRx loss). The requested power negotiation value may omit or ignore the power transmission loss (PTx loss) because it is estimated and taken into account by the power transmitter during power negotiation. The power receiver and power transmitter may negotiate a guaranteed power based on the requested power negotiation value, the estimated PTx loss, and the available power. For example, the power transmitter may accept or reject the requested power negotiation value as the guaranteed power. For example, the power transmitter may accept the requested power negotiation value as the guaranteed power if the available power is greater than the sum of the requested power negotiation value and the estimated PTx loss. Alternatively, the power transmitter may not be able to accept the requested power negotiation value as the guaranteed power. For example, the power transmitter may determine that the available power is less than the requested power negotiation value plus the estimated PTx loss. The power transmitter may communicate a message to the power receiver indicating that the power transmitter rejects the requested power negotiation value. In some implementations, the power receiver may communicate a subsequent requested power negotiation value and await acceptance or rejection of the requested power negotiation value as the guaranteed power. In some implementations, the power transmitter may calculate an alternative power negotiation value that the power transmitter can meet based on the available power minus the estimated PTx loss. The power transmitter may communicate the alternative power negotiation value (also referred to as a proposed power negotiation value) to the power receiver. The power receiver may respond with an affirmative response if it accepts the alternative power negotiation value as the guaranteed power.

[0063] Once guaranteed power is negotiated, the transmitter can reserve the negotiated power (based on the sum of the guaranteed power and the estimated PTx loss) from its available power, thereby reducing the available power of other transmitters that share the available power. Each transmitter can perform similar power negotiations (and reserve the negotiated power) with each receiver using the available power remaining after reservations from other transmitters. Because the negotiated power takes into account the estimated PTx loss, the total power usage by multiple transmitters does not exceed the maximum power of the source.

[0064] From the connection phase 530, the power receiver can request the power transmitter to transition to the power transfer phase 540 or return to the idle phase 510. In the power transfer phase 540, the power transmitter performs a foreign object detection (FOD) operation and then applies a power signal to transmit wireless power to the power receiver, repeating this cycle during the power transfer phase 540. Communication or FOD is performed during each slot of the power signal. Some examples of communication in the power transfer phase 540 may be related to power negotiation. For example, during the power transfer phase 546, the power receiver may communicate a power request (P-request) message (also referred to as "request power" or CTRL / rpl) to the power transmitter to adjust the power level of the wireless power transfer to the power receiver. The requested power during the power transfer phase must not exceed the guaranteed power negotiated between the power transmitter and the power receiver.

[0065] 6 shows a block diagram 600 conceptually illustrating a communication protocol. The power transmitter 102 can communicate with the power receiver 118. The communication protocol may include messages 610 from the power transmitter 102 to the power receiver 118, or messages 620 from the power receiver 118 to the power transmitter 102, or both. The present disclosure includes several enhancements to 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.

[0066] Below (by way of example embodiments) are listed some example enhancements that may be implemented in the communication protocol: Further examples are provided with reference to Figures 7 to 13.

[0067] Exemplary Embodiment 1 The power transmitter can decide to enter the standby phase (from the power transfer phase) independently of any power receiver request. For example, the power transmitter may use the NEXT / stb command or may turn off the power signal and communication carrier. The power transmitter may send a message requesting the power receiver to enter a standby state. The power receiver checks whether it can do this depending on the state the power receiver is currently in (e.g., no user interaction, no intention to operate). Thus, the power transmitter can communicate with the power receiver to request a standby mode transition.

[0068] In some aspects, the power receiver can send a communication message to the power transmitter requesting the power transmitter to enter a standby state, and the power transmitter can determine, via a user interface on the power transmitter, whether it can enter a standby state based on regulatory requirements and other activities.

[0069] Exemplary Embodiment 2 The power transmitter and receiver can communicate measurement information to assist in power control. Measurement (MEAS) messages are used to exchange measurements of indicated parameters. MEAS messages may enable communication of power levels, surface temperatures, version information, buffer information, status, or identification. In some aspects, the MEAS message may be modified to enable communication of PRx voltage, PRx current, or both via the MEAS message from the receiver to the transmitter. Appendix A shows exemplary message formats that can be incorporated into the MEAS message.

[0070] Exemplary Embodiment 3 The communication protocol may include messages that allow the power transmitter to notify the power receiver about fault conditions detected at the power transmitter. For example, messages may be used to indicate abnormal temperatures, overcurrents or overvoltages, the presence of foreign objects, among other exemplary error conditions. By knowing the error condition of the power transmitter, the power receiver may adapt or cease wireless power transfer to mitigate the error condition.

[0071] FIG. 7 shows an example message flow diagram 700 conceptually illustrating an example communication enhancement. As shown in block 710, the power transmitter 102 can set a PTx minimum supported power level for the power transmitter 102. The PTx minimum supported power level may be based on the measurement and processing capabilities of the power transmitter. Currently, conventional communication protocols do not define a PTx minimum supported power level (a non-zero number). For example, a low PTx minimum supported power level of one watt (1 W) may be difficult for the power transmitter 102 to adjust to. Alternatively or additionally, the PTx minimum supported power level may be based on device capabilities, sensor tolerance, or processing sensitivity. The power transmitter 102 may not be able to adjust at an operating point with a requested power level below the PTx minimum supported power level.

[0072] During the power transfer phase 706, the power receiver 118 may communicate control messages (e.g., CTRL / rpl messages) to the power transmitter 102 to periodically or periodically adjust the power level of the power channel. In FIG. 7, control message 750 may be an example of a CTRL / rpl message. The power receiver 118 may attempt to set the power level to a value that is too low for the power transmitter to effectively adjust. As a result, the power transmitter 102 may unnecessarily transmit power to the power receiver 118 while attempting to reach a requested power level that is below the PTx minimum supported power level, potentially resulting in an overvoltage condition at the power receiver. As shown in block 760, the power transmitter 102 may determine that the power control message 750 indicates a requested power level that is below the PTx minimum supported power level.

[0073] If the power request (in power control message 750) falls below its PTx minimum supported power level, the transmitter 102 can transition from the power transfer phase 706 to a pre-power phase (such as the connection phase or configuration phase). The transmitter 102 can terminate the power transfer and communicate a message (shown in message 770) to transition the receiver 118 to the connection phase.

[0074] In some implementations, the power receiver 118 can communicate a configuration value 730 during a pre-power transfer phase (e.g., a configuration phase or a connection phase). The configuration value 730 may indicate a PRx minimum power limit (PRx-min-power) that the power receiver 118 requests during the power transfer phase 706. The power transmitter 102 may verify, before the power transfer phase 706, that the PRx-min-power is higher than the PTx minimum supported power level.

[0075] In some implementations, the power transmitter 102 may communicate the PTx minimum supported power level to the power receiver in message 720, allowing the power receiver 118 to manage power requests or phase transitions according to the PTx minimum supported power level.

[0076] FIG. 7 may also be used to illustrate another exemplary aspect. As described herein, the communication protocol may include a power control message (e.g., a CTRL / rpl message) in which the power receiver 118 requests a power level. The power transmitter is expected to control the power transmitted from the primary coil to within a percentage (e.g., 5-10%) of the requested power level within a time interval (e.g., 10-50 milliseconds) after receiving the CTRL / rpl message. During the power transfer phase 706, the power transmitter 102 may exceed a current limit, or a power limit may occur for various reasons, such as a sudden power receiver misalignment or undervoltage in the power transmitter's source input power (e.g., AC power). Conventional implementations of power transmitters may allow the power transmitter 102 to ignore the CTRL / rpl message in such cases. For example, a conventional power transmitter may ignore a requested power level (CTRL / rpl) coming from the power receiver 118 if the requested power level would cause the PTx power or current to exceed its limits. However, the receiver 118 may be unaware of the limits or may be unaware when the CTRL / rpl message is ignored due to an over-limit condition. In some implementations, instead of ignoring the power level request, the transmitter 102 implementing aspects of the present disclosure may initiate a renegotiation with the receiver to adjust the power level request limit from the receiver side.

[0077] In some aspects, at block 760, the power control message 770 may indicate a requested power level that would cause the power transmitter 102 to exceed its current or power limits, or the power transmitter 102 may determine that it cannot meet guaranteed power. The power transmitter 102 may transition from the power transfer phase 706 to the connection phase. In some implementations, the power transmitter may communicate message 770 to the power receiver 118 to transition to the connection phase. The message 770 may also indicate that the requested power level (in the power control message 750) will exceed its limits. For example, the message 770 may include an explicit indication that the limits will be exceeded, or may be an implicit indication based on an error indicator or a phase change.

[0078] In some implementations, after transitioning from the power transfer phase 706, the power transmitter 102 can communicate a proposed power negotiation value (to establish a new guaranteed power level) for a subsequent power transfer phase (not shown). The proposed power negotiation value may indicate the guaranteed power that the power transmitter 102 can support based on the current state of the power transmitter 102.

[0079] FIG. 8 shows a message flow diagram 800 conceptually illustrating an example power negotiation. The power transmitter 102 and the power receiver 118 can establish communication during a configuration phase 802 and exchange identification and configuration messages 810. In a connection phase 804, the power transmitter 102 and the power receiver 118 can perform power negotiation. In some implementations, the power transmitter 102 can determine and communicate a negotiation message 820 indicating available power or maximum power. At 830, the power receiver 118 can determine a requested power negotiation value. The requested power negotiation value may be based on the power rating and power reception loss (PRx loss) of the power receiver 118. The PRx loss may be estimated, calculated, measured, or programmatically configured. The power receiver 118 can communicate a negotiation message 840 including the requested power negotiation value. At 842, the power transmitter 102 can estimate power transmission loss (PTx loss). The PTx loss may be estimated, calculated, measured, or programmatically configured. In some implementations, the estimated PTx loss may be a loss that is expected to reduce the actual transmitted power to the power receiver 118 based on the current state and a requested power level associated with the requested power negotiation value.

[0080] If the power transmitter 102 is able to reserve an amount of power corresponding to the requested power negotiation value and the PTx loss, the power transmitter 102 may communicate a response message 844 indicating whether the power transmitter 102 accepts the requested power negotiation value as guaranteed power. Otherwise, if the power transmitter 102 is unable to reserve an amount of power corresponding to the requested power negotiation value and the PTx loss, the power transmitter 102 may communicate a response message 844 indicating that the power transmitter 102 rejects the requested power negotiation value.

[0081] In traditional power negotiation, the power receiver 118 can continue to use a requested power negotiation value (not shown), lowering the requested power negotiation value each time in successive messages, and receive a response from the power transmitter. This series of messages can continue until the power transmitter 102 accepts the requested power negotiation value. However, such a process can be time-consuming and frustrating for the user. According to some aspects of the present disclosure, instead of sending another power request, the power receiver 118 can communicate a requested negotiation value request message 850 (e.g., a NEGO / rqp message) to the power transmitter 102 and provide a proposed power negotiation value (e.g., a proposed guaranteed power in a NEGO / avp or other power negotiation message). The power transmitter 102 can respond with the proposed power negotiation value in message 860. Thereafter, if the proposed power negotiation value is acceptable to the power receiver 118, the power receiver 118 can send the proposed power negotiation value as the requested power negotiation value, which avoids multiple renegotiations, and if there is enough guaranteed power to operate the PRx, it can decide to proceed to the power transfer phase, otherwise it can send a NEXT / stb or NEXT / con command.

[0082] In some implementations, the power transmitter 102 can communicate a negotiation message to indicate an alternative power negotiation value in addition to or instead of the response message 870. In some implementations, the alternative power negotiation value by the transmitter may correspond to the available power minus the estimated PTx loss.

[0083] Continuing with reference to FIG. 8 , in the illustrated example, the power transmitter 102 accepts the requested power negotiation value. At 872, the power transmitter 102 sets a guaranteed power based on the requested power negotiation value. The power transmitter 102 also calculated the negotiated power as the sum of the guaranteed power and the estimated PTx loss. The power transmitter 102 then reserves the negotiated power from the available power. The available power of the power source may be reduced by the negotiated power so that it is reserved for the power transmitter 102 and is not available for other power transmitters sharing the power source. At 874, the power receiver 118 can set the guaranteed power as a maximum limit for subsequent power request messages communicated during the power transfer phase.

[0084] During the power transfer phase 806, the power receiver 118 can transmit a power request (P-request) message 880 or other feedback message to request an adjustment of wireless power transmission. For example, the power request message 880 may include a P-request, as described with reference to FIG. 6. The P-request may be limited to not exceed the guaranteed power negotiated with the power transmitter 102 based on a requested power negotiation value.

[0085] At 882, the transmitter 102 can calculate PTx losses based on measurements at the inverter of the transmitter 102. At 884, the transmitter 102 can determine new operating parameters to satisfy the P-request, taking into account the calculated PTx losses.

[0086] FIG. 9 illustrates an example communication technique 900 for a power receiver to indicate status. Conventional communication messages from a power transmitter to a power receiver provide a field for the power transmitter to indicate PTx status. However, currently, no technique exists for the power receiver to indicate PRx status. Furthermore, as new features and fault handling techniques are implemented, there is a need for the power transmitter to be aware of the PRx status. In some aspects, a communication message from a power receiver to a power transmitter may include a status field (e.g., PRx status). The status field may be one or more bits. In some implementations, the status field is a byte with various bits assigned to status values ​​or indicators.

[0087] Exemplary PRx status indicators 910 may include an indication of whether wired power is available. For example, this indication may be useful for a hybrid PRx that supports both wired and wireless power sources. A status bit (such as a “wired on” indicator) may indicate whether the PRx (equipment) is powered by a wired power source. A first value (such as a “1”) on this status bit may indicate that the equipment is powered by a wired power source (such as an AC power source), and a second value (such as a “0”) may indicate that the PRx requires wireless power from the PTx. Other exemplary PRx status indicators 910 may include an indication of whether a protection switch is open or closed or an indication of PRx fault status. The exemplary PRx status indicators are provided for educational purposes and are not intended as an exhaustive or exclusive list. Additionally, some implementations may omit or include various of the exemplary PRx status indicators described herein.

[0088] In some implementations, a status field may be included in the MEAS or RQST message. Furthermore, because the PRx can communicate its status in the MEAS or RQST message, conventional techniques for determining whether the PRx is active (such as an ECHO message) may be eliminated. The status communicated by the receiver can function as a heartbeat or keep-alive presence indicator, communicated by a separate message and communication overhead.

[0089] 10 shows a message flow diagram 1000 conceptually illustrating an example communication technique for addressing misalignment during the power transfer phase. The power transmitter 102 and the power receiver 118 can establish a power agreement (e.g., guaranteed power) during power negotiation 1010. During the power transfer phase 1006, the power receiver 118 can communicate a power control message 1020. In block 1030, the power transmitter 102 may determine that it is operating at a power limit or that it cannot meet the guaranteed power. For example, a misalignment that occurs after the power negotiation 1010 may result in a reduced amount of power transfer. The misalignment may cause changing conditions that prevent the power transmitter from transmitting enough power to meet the guaranteed power.

[0090] At block 1040, the power transmitter 102 can initiate k-factor measurement using any of a variety of known k-factor determination techniques. At block 1050, the power transmitter 102 can determine whether the k-factor is within a threshold range considered acceptable for power transfer. If the k-factor is outside the threshold range, the power transmitter 102 can communicate a warning message 1070 to the power receiver 118. The warning message 1070 may prompt the user to realign the power receiver 118 to correct the misalignment. After one or more warning messages 1070, or after a predetermined time that the misalignment persists, the power transmitter 102 can transition from the power transfer phase 1006 to the connection phase (shown in block 1080). In some implementations, at block 1090, the power transmitter 102 can communicate a message indicating that the misalignment is outside a threshold range that prevents the power transmitter 102 from meeting the requested power level. In some implementations, the power transmitter 102 may initiate a new power negotiation or may indicate a fault status.

[0091] FIG. 11 shows a diagram of communication carrier voltage values ​​adjusted during the power transfer phase. In some implementations, the communication carrier value may be the voltage amplitude, peak value, or RMS value of the communication carrier. Conventional wireless power systems require the communication carrier level (e.g., the voltage of the NFC signal) to remain constant during the power transfer phase 1090. However, this can cause loss of communication capability, communication data fidelity, or other communication errors, especially if misalignment occurs during the power transfer phase.

[0092] According to some aspects of the present disclosure, the communications carrier level may be adjusted during the power transfer phase 1090. The power transmitter may use a first carrier level 1110 at the start of the power transfer phase 1090. As shown by line 1030, the power transmitter may initiate a coupling coefficient measurement. For example, the power transmitter may communicate a command requesting the power receiver to communicate a measured communications signal voltage. The power transmitter may determine that the communications coupling has changed and adjust the communications signal to a second communications carrier level 1140. The communications carrier level may refer to voltage, power, or both. In some implementations, communications voltage measurements may be performed periodically during the power transfer phase 1090. Alternatively or additionally, communications coupling coefficient or voltage measurements may be performed in response to detecting a change in the k-factor (power signal coupling coefficient). Alternatively or additionally, communications coupling coefficient measurements may be performed after a threshold amount of communications errors or a negative acknowledgement (NAK) message from the power receiver.

[0093] FIG. 12 shows a message flow diagram 1200 conceptually illustrating an example technique for addressing communication failures during the power transfer phase 1206. The power transmitter 102 and the power receiver 118 can establish a power agreement (e.g., guaranteed power) during power negotiation 1212. During the power transfer phase 1206, the power receiver 118 can communicate a message 1220 to the power transmitter 102. For example, the message 1220 can be a power control message (e.g., CTRL / rpl) or a phase transition message (e.g., NEXT / con message). However, due to a communication error, a PTx controller malfunction, or a fault condition in the power transmitter, the power transmitter 102 may not act on the message 1220. In block 1230, the power receiver 118 can determine that the power transmitter 102 is not processing the message 1220. For example, the power receiver 118 may assume that the power transmitter 102 is not responding to the power control message or the phase transition message.

[0094] In block 1280, the power receiver 118 can initiate mitigation techniques related to a communication failure in the wireless power system. For example, the power receiver 118 can open a protection switch in the power receiver circuit of the power receiver 118 when the alternating current (AC) cycle voltage is near zero (e.g., during or near a communication slot). This prevents high current interruption that could otherwise cause overvoltage or overcurrent high enough to damage components of the power receiver 118 or the power transmitter 102. In some implementations, the power receiver 118 can open the protection switch when the AC cycle voltage is below a threshold level to disconnect the secondary coil of the power receiver 118 from other components of the power receiver circuit. The power receiver 118 can collect basic operating power from the wireless power signal during the communication slot. In some implementations, the power receiver 118 may present a user interface (UI) indication of the communication failure and power down the power receiver 118.

[0095] 13 is a flowchart of an example process 1300. In some implementations, one or more process blocks of FIG. 13 may be performed by the power transmitter.

[0096] 13, process 1300 may include setting a PTx minimum supported power level for the transmitter, where the PTx minimum supported power level is based on the measurement and processing capabilities of the transmitter (block 1310). For example, the transmitter may set the PTx minimum supported power level for the transmitter, where the PTx minimum supported power level is based on the measurement and processing capabilities of the transmitter, as described above.

[0097] 14 is a flowchart of an example process 1400. In some implementations, one or more process blocks of FIG. 14 may be performed by the power transmitter.

[0098] As shown in FIG. 14 , process 1400 may include transferring power from the power transmitter to the power receiver during a power transfer phase after the first power negotiation (block 1410). For example, the power transmitter can transfer power from the power transmitter to the power receiver during the power transfer phase after the first power negotiation, as described above. As also shown in FIG. 14 , process 1400 may include receiving a power control message from the power receiver (block 1420). For example, the power transmitter can receive the power control message from the power receiver, as described above. As further shown in FIG. 14 , process 1400 may include determining that the power control message indicates a requested power level that would cause the power transmitter to exceed a current limit or a power limit of the power transmitter, or that the power transmitter cannot meet the guaranteed power established in the first power negotiation (block 1430). For example, the transmitter may determine that the power control message indicates a requested power level that would cause the transmitter to exceed its current or power limits, as described above, or that the transmitter cannot meet the guaranteed power established in the first power negotiation. As also shown in FIG. 14, process 1400 may include transitioning from the power transfer phase to the connection phase (block 1440). For example, the transmitter can transition from the power transfer phase to the connection phase, as described above.

[0099] 15 is a flowchart of an example process 1500. In some implementations, one or more process blocks of FIG. 15 may be performed by the power transmitter.

[0100] As shown in FIG. 15 , process 1500 may include performing power negotiation with the power receiver during the connection phase (block 1510). For example, the power transmitter can perform power negotiation with the power receiver during the connection phase, as described above. As also shown in FIG. 15 , process 1500 may include receiving a negotiation value request message from the power receiver (block 1520). For example, the power transmitter can receive the negotiation value request message from the power receiver, as described above. As further shown in FIG. 15 , process 1500 may include communicating proposed negotiation values ​​to the power receiver in response to the negotiation value request message (block 1530). For example, as described above, the power transmitter can communicate proposed negotiation values ​​to the power receiver in response to the negotiation value request message.

[0101] 16 is a flowchart of an example process 1600. In some implementations, one or more process blocks of FIG. 16 may be performed by a power transmitter.

[0102] 16, process 1600 may include obtaining a communication message from the power receiver, the communication message including a status field indicating the status of the power receiver (block 1610). For example, the power transmitter can obtain a communication message from the power receiver, as described above, the communication message including a status field indicating the status of the power receiver.

[0103] 17 is a flowchart of an example process 1700. In some implementations, one or more process blocks of FIG. 17 may be performed by the power transmitter.

[0104] As shown in FIG. 17 , process 1700 may include transferring power to the receiver during the power transfer phase (block 1710). For example, the transmitter may transfer power to the receiver during the power transfer phase, as described above. As also shown in FIG. 17 , process 1700 may include detecting a misalignment condition that causes the transmitter to operate beyond the PTx limit or prevents the transmitter from meeting the guaranteed power at the PTx limit (block 1720). For example, the transmitter may detect a misalignment condition that causes the transmitter to operate beyond the PTx limit or prevents the transmitter from meeting the guaranteed power at the PTx limit, as described above.

[0105] 18 is a flowchart of an example process 1800. In some implementations, one or more process blocks of FIG. 18 may be performed by the power transmitter.

[0106] 18, process 1800 may include adjusting a communication carrier level of a communication signal during a power transfer phase with the power receiver (block 1810). For example, the power transmitter can adjust a communication carrier level of a communication signal during a power transfer phase with the power receiver, as described above.

[0107] 19 is a flowchart of an example process 1900. In some implementations, one or more process blocks of FIG. 19 may be performed by a power receiver.

[0108] As shown in FIG. 19 , process 1900 may include communicating a power control message to the transmitter during the power transfer phase, where the power control message indicates a requested power level (block 1910). For example, the receiver may communicate a power control message to the transmitter during the power transfer phase, where the power control message indicates a requested power level, as described above. As also shown in FIG. 19 , process 1900 may include determining that the transmitter has transitioned from the power transfer phase to the connection phase due to the requested power level being less than the PTx minimum supported power level (block 1920). For example, the receiver may determine that the transmitter has transitioned from the power transfer phase to the connection phase due to the requested power level being less than the PTx minimum supported power level, as described above.

[0109] 20 is a flowchart of an example process 2000. In some implementations, one or more process blocks of FIG. 20 may be performed by a power receiver.

[0110] As shown in FIG. 20 , process 2000 may include receiving power from the power transmitter during a power transfer phase after the first power negotiation (block 2010). For example, the power receiver can receive power from the power transmitter during the power transfer phase after the first power negotiation, as described above. As also shown in FIG. 20 , process 2000 may include communicating a power control message to the power transmitter (block 2020). For example, the power receiver can communicate a power control message to the power transmitter, as described above. As further shown in FIG. 20 , process 2000 may include receiving a phase transition message from the power transmitter indicating a requested power level that would cause the power transmitter to exceed a current or power limit of the power transmitter, or indicating that the power transmitter cannot meet the guaranteed power established in the first power negotiation (block 2030). For example, the receiver may receive a phase transition message from the transmitter indicating a requested power level that would cause the transmitter to exceed a current or power limit of the transmitter, or indicating that the transmitter cannot meet the guaranteed power established in the first power negotiation, as described above. As also shown in FIG. 20, process 2000 may include transitioning from the power transfer phase to the connection phase (block 2040). For example, the receiver can transition from the power transfer phase to the connection phase, as described above.

[0111] 21 is a flowchart of an example process 2100. In some implementations, one or more process blocks of FIG. 21 may be performed by a power receiver.

[0112] As shown in FIG. 21 , process 2100 may include performing power negotiation with the power transmitter during the connection phase (block 2110). For example, the power receiver may perform power negotiation with the power transmitter during the connection phase, as described above. As also shown in FIG. 21 , process 2100 may include communicating a negotiation value request message to the power transmitter (block 2120). For example, the power receiver may communicate the negotiation value request message to the power transmitter, as described above. As further shown in FIG. 21 , process 2100 may include receiving proposed negotiation values ​​from the power transmitter in response to the negotiation value request message (block 2130). For example, the power receiver may receive proposed negotiation values ​​from the power transmitter in response to the negotiation value request message, as described above.

[0113] 22 is a flowchart of an example process 2200. In some implementations, one or more process blocks of FIG. 22 may be performed by a power receiver.

[0114] 22, process 2200 may include communicating a communication message to the power transmitter, the communication message including a status field indicating the status of the power receiver (block 2210). For example, the power receiver may communicate a communication message to the power transmitter, the communication message including a status field indicating the status of the power receiver, as described above.

[0115] 23 is a flowchart of an example process 2300. In some implementations, one or more process blocks of FIG. 23 may be performed by a power receiver.

[0116] As shown in FIG. 23 , process 2300 may include receiving a wireless power signal from a power transmitter during a power transfer phase (block 2310). For example, the power receiver may receive a wireless power signal from the power transmitter during the power transfer phase, as described above. As also shown in FIG. 23 , process 2300 may include communicating a control message or phase transition message to the power transmitter (block 2320). For example, the power receiver may communicate a control message or phase transition message to the power transmitter, as described above. As further shown in FIG. 23 , process 2300 may include determining that the power transmitter did not process the control message or phase transition message within an expected period of time (block 2330). For example, the power receiver may determine that the power transmitter did not process the control message or phase transition message within an expected period of time, as described above. As also shown in FIG. 23 , process 2300 may include initiating a mitigation technique associated with a communication failure in the wireless power system (block 2340). For example, the receiver may initiate mitigation techniques associated with communication disruptions in the wireless power system, as described above.

[0117] 13-23 illustrate example blocks of processes 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, and 2300, respectively, in some implementations, processes 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, and 2300 may include additional, fewer, different, or differently arranged blocks than those illustrated in Figures 13-23. Additionally or alternatively, two or more of the blocks of processes 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, and 2300 may be performed in parallel.

[0118] FIG. 24 is a block diagram of an exemplary apparatus for use in a wireless power system. In some implementations, the apparatus 2400 may be a power transmitter (such as the power transmitter 102) described herein. In some implementations, the apparatus 2400 may be an example of any one of the power transmitters 102 or 300, or any one of the TX controllers 108 described with reference to any of the figures herein. The apparatus 2400 may include a processor 2402 (possibly including multiple processors, multiple cores, multiple nodes, multithreading, etc.). The apparatus 2400 may also include a memory 2406. The memory 2406 may be system memory or any one or more of the possible implementations of the computer-readable media described herein. The apparatus 2400 may also include a bus 2411 (e.g., PCI, ISA, PCI-Express, HyperTransport®, InfiniBand®, NuBus, AHB®, AXI, etc.).

[0119] The device 1100 may include one or more controllers 2462 configured to manage multiple primary or secondary coils (such as a coil array 2464). In some implementations, the controller 2462 may be distributed within the processor 2402, the memory 2406, and the bus 2411. The controller 2462 may perform some or all of the operations described herein. For example, the controller 2462 may be a transmission controller, such as any of the transmission controllers described herein.

[0120] The memory 2406 may include computer instructions executable by the processor 2402 to perform the functions of the implementations described with reference to Figures 1-5. Any of these functions may be implemented partially (or entirely) in hardware or in the processor 2402. For example, the functions may be implemented in an application specific integrated circuit, logic implemented in the processor 2402, a co-processor on a peripheral device or card, etc. Furthermore, an implementation may include fewer or additional components not shown in Figure 24. The processor 2402, the memory 2406, and the controller 2462 may be coupled to a bus 2411. While shown as coupled to the bus 2411, the memory 2406 may also be coupled to the processor 2402.

[0121] 1 through 24 and the operations described herein are examples intended to aid in understanding example implementations and should not be used to limit potential implementations or to limit the scope of the claims. Some implementations may perform additional operations, fewer operations, operations in parallel or in a different order, and some different operations.

[0122] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or acquired from practice of the aspects. Although aspects of the present disclosure have been described with reference to various examples, any combination of aspects from any example is within the scope of the present disclosure. The examples of the present disclosure are provided for educational purposes. Alternatively, or in addition to other examples described herein, examples include any combination of the following implementation options (listed as clauses for clarity):

[0123] Terms Clause 1. A method for a power transmitter (PTx) in a wireless power system, comprising: setting a PTx minimum supported power level for the power transmitter, the PTx minimum supported power level being based on measurement and processing capabilities of the power transmitter.

[0124] Clause 2. The method of clause 1, further comprising the steps of receiving a power control message from the power receiver during the power transfer phase, determining that the power control message indicates a requested power level that is less than the PTx minimum supported power level, and transitioning from the power transfer phase to a connection phase.

[0125] Clause 3. The method of clause 2, wherein the step of transitioning from the power transfer phase to the connection phase includes the steps of terminating power transfer to the power receiver and communicating a message to cause the power receiver to transition to the connection phase.

[0126] Clause 4. The method of any one of clauses 1 to 3, further comprising the steps of receiving a configuration value from the power receiver indicating a minimum power limit (PRx-min-power) of the power receiver (PRx) required by the power receiver during the power transfer phase, and verifying that PRx-min-power is higher than the PTx minimum supported power level.

[0127] Clause 5. The method of any one of clauses 1 to 4, further comprising the step of communicating the PTx minimum supported power level to the power receiver.

[0128] Clause 6. A method for a power transmitter (PTx) in a wireless power system, comprising: transferring power from the power transmitter to a power receiver during a power transfer phase after a first power negotiation; receiving a power control message from the power receiver; determining that the power control message indicates a requested power level that would cause the power transmitter to exceed a current limit or power limit of the power transmitter or that the power transmitter is unable to meet the guaranteed power established in the first power negotiation; and transitioning from the power transfer phase to a connection phase.

[0129] Clause 7. The method of clause 6, wherein the step of transitioning from the power transfer phase to the connection phase includes the steps of terminating power transfer to the power receiver and communicating a message to cause the power receiver to transition to the connection phase.

[0130] Clause 8. The method of clause 7, further comprising: initiating a second power negotiation after transitioning to the connection phase; and the second power negotiation establishing a second guaranteed power that replaces the first guaranteed power.

[0131] Clause 9. The method of clause 8, further comprising the step of communicating a proposed power negotiation value during the second power negotiation, the proposed power negotiation value indicating a second guaranteed power that the transmitter can support based on a current state of the transmitter.

[0132] Clause 10. A method for a power transmitter (PTx) in a wireless power system, comprising the steps of: performing power negotiation with a power receiver during a connection phase; receiving a negotiation value request message from the power receiver; and communicating a proposed negotiation value to the power receiver in response to the negotiation value request message.

[0133] Clause 11. The method of clause 10, wherein the proposed negotiation value is based on a guaranteed power that the power transmitter can guarantee to transfer to the power receiver or is based on the power transmitter's available power.

[0134] Clause 12. The method of any one of clauses 10 to 11, further comprising the step of receiving a requested power negotiation value from the power receiver, wherein the requested power negotiation value is based on the proposed negotiation value.

[0135] Clause 13. A method for a power transmitter (PTx) in a wireless power system, comprising the step of obtaining a communication message from a power receiver, the communication message including a status field indicating a status of the power receiver.

[0136] Clause 14. The method of clause 13, wherein the communication message is a measurement (MEAS) message or a request (RQST) message, and the status field is included in the MEAS or RQST message.

[0137] Clause 15. The method of any one of clauses 13 to 14, wherein the status field includes at least one indicator selected from the group consisting of an indication of whether the power receiver has available wired power, an indication of whether a protection switch is open or closed, and an indication of a fault status.

[0138] Clause 16. The method of any one of clauses 13 to 15, wherein the step of obtaining the communication message includes the step of reading a passive tag of the wireless communication unit of the receiver.

[0139] Clause 17. A method for a power transmitter (PTx) in a wireless power system, comprising the steps of transferring power to a power receiver during a power transfer phase, and detecting a misalignment condition that causes the power transmitter to operate beyond the PTx limits or prevents the power transmitter from meeting guaranteed power at the PTx limits.

[0140] Clause 18. The method of clause 17, wherein the step of detecting a misalignment condition includes the steps of measuring a coupling coefficient (k factor) between the transmitter and the receiver, determining that the k factor is not within a threshold range, and communicating a warning message to the receiver indicating that the k factor is outside the threshold range.

[0141] Clause 19. The method of clause 18, further comprising transitioning to a connection phase in response to detecting a misalignment condition or after the misalignment condition has persisted for a threshold time.

[0142] Clause 20. A method according to any one of clauses 17 to 19, wherein the step of transitioning from the power transfer phase to the connection phase includes the steps of terminating power transfer to the receiver and communicating a message to cause the receiver to transition to the connection phase.

[0143] Clause 21. A method according to any one of clauses 17 to 20, wherein the step of detecting a misalignment condition comprises the steps of verifying that no power transfer fault is indicated or identified by the receiver or by the receiver that would cause the transmitter to operate beyond the PTx limit or prevent the transmitter from meeting its guaranteed power at the PTx limit, and detecting a misalignment condition when the coupling coefficient (k factor) is outside a threshold range and no power transfer fault is indicated or identified.

[0144] Clause 22. A method of a power transmitter (PTx) in a wireless power system, comprising adjusting a communication carrier level of a communication signal during a power transfer phase with a power receiver.

[0145] Clause 23. The method of clause 22, further comprising the steps of: obtaining a measurement value from the power receiver during the power transfer phase, the measurement value indicating a measured voltage level of a communication signal received by the power receiver; and adjusting the communication carrier level based on the measurement value.

[0146] Clause 24. The method of any one of clauses 22 to 23, further comprising the steps of detecting a change in alignment between the first communication unit of the power transmitter and the second communication unit of the power receiver, and adjusting a communication carrier level based on the change in alignment.

[0147] Clause 25. A power transmitter including a controller configured to perform any one of the methods of clauses 1 to 24.

[0148] Clause 26. A method for a power receiver (PRx) in a wireless power system, comprising the steps of: communicating a power control message to a power transmitter during a power transfer phase, the power control message indicating a requested power level; and determining that the power transmitter has transitioned from the power transfer phase to a connection phase due to the requested power level being less than a PTx minimum supported power level.

[0149] Clause 27. The method of clause 26, further comprising communicating a configuration value from the receiver to the transmitter indicating a PRx minimum power limit (PRx-min-power) required by the receiver during the power transfer phase.

[0150] Clause 28. The method of any one of clauses 26 to 27, further comprising receiving a communication from the transmitter indicating a PTx minimum supported power level.

[0151] Clause 29. A method for a power receiver (PRx) in a wireless power system, comprising the steps of receiving power from a power transmitter during a power transfer phase after a first power negotiation, communicating a power control message to the power transmitter, receiving a phase transition message from the power transmitter indicating a requested power level that would cause the power transmitter to exceed a current limit or a power limit of the power transmitter or indicating that the power transmitter is unable to meet a guaranteed power established in the first power negotiation, and transitioning from the power transfer phase to a connection phase.

[0152] Clause 30. The method of clause 32, further comprising initiating a second power negotiation after transitioning to the connection phase, the second power negotiation comprising establishing a second guaranteed power that replaces the first guaranteed power.

[0153] Clause 31. The method of clause 30, further comprising: receiving a proposed power negotiation value from the transmitter during a second power negotiation, the proposed power negotiation value indicating a second guaranteed power that the transmitter can support based on a current state of the transmitter.

[0154] Clause 32. A method for a power receiver (PRx) in a wireless power system, comprising the steps of: performing power negotiation with a power transmitter during a connection phase; communicating a negotiation value request message to the power transmitter; and receiving a proposed negotiation value from the power transmitter in response to the negotiation value request message.

[0155] Clause 33. The method of clause 32, wherein the proposed negotiation value is based on a guaranteed power that the power transmitter can guarantee to transfer to the power receiver or is based on the power transmitter's available power.

[0156] Clause 34. The method of any one of clauses 32 to 33, further comprising the step of communicating a requested power negotiation value from the power receiver, the requested power negotiation value being based on the proposed negotiation value.

[0157] Clause 35. A method for a power receiver (PRx) in a wireless power system, comprising the step of communicating a communication message to a power transmitter, the communication message including a status field indicating a status of the power receiver.

[0158] Clause 36. The method of clause 35, wherein the communication message is a measurement (MEAS) message or a request (RQST) message, and the status field is included in the MEAS or RQST message.

[0159] Clause 37. The method of any one of clauses 35 to 36, wherein the status field includes at least one indicator selected from the group consisting of an indication of whether the power receiver has available wired power, an indication of whether a protection switch is open or closed, and an indication of a fault status.

[0160] Clause 38. The method of any one of clauses 35 to 37, wherein the step of communicating the communication message includes the step of storing the communication message in a passive tag of the wireless communication unit of the receiver so that the communication message can be read by a corresponding communication unit of the transmitter.

[0161] Clause 39. A method for a power receiver (PRx) in a wireless power system, comprising the steps of receiving a wireless power signal from a power transmitter during a power transfer phase, communicating a control message or a phase transition message to the power transmitter, determining that the power transmitter has not processed the control message or the phase transition message within an expected period of time, and initiating a mitigation technique associated with a communication failure in the wireless power system.

[0162] Clause 40. The method of clause 39, wherein the mitigation technique includes opening a protection switch in a power receiving circuit of the power receiver during a final portion of an alternating current (AC) cycle of the wireless power signal.

[0163] Clause 41. The method of clause 40, wherein the mitigation technique includes the steps of opening a protection switch to disconnect the secondary coil of the receiver from other components of the receiver circuit during a period in which the voltage of the AC cycle is below a threshold level, and harvesting basic operating power from the wireless power signal or communication signal during a communication period in which communication between the transmitter and receiver occurs.

[0164] Clause 42. The method of any one of clauses 39 to 41, wherein the mitigation technique includes the steps of presenting a user interface (UI) indication indicating a communication failure and powering off the receiver.

[0165] Clause 43. A power receiver including a controller configured to perform any one of the methods of clauses 26 to 42.

[0166] Another innovative aspect of the subject matter described in this disclosure can be implemented in a wireless power receiving device. The device may include a modem and at least one processor communicatively coupled to the modem. The processor may be configured, in cooperation with the modem, to perform any one of the foregoing methods or features described herein.

[0167] Another innovative aspect of the subject matter described in this disclosure can be implemented as a computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform any one of the above methods or features described herein.

[0168] Another innovative aspect of the subject matter described in this disclosure can be embodied as a system having means for performing any one of the above methods or features described herein.

[0169] As used herein, phrases referring to "at least one of" or "one or more of" a list of items refer to any combination of those items, including single members. For example, "at least one of: a, b, or c" is intended to cover the possibilities of a only, b only, c only, a and b combinations, a and c combinations, b and c combinations, and a, b, and c combinations.

[0170] The various exemplary components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware, or software, including the structures disclosed herein and structural equivalents thereof. The interchangeability of hardware, firmware, and software is generally described in terms of functionality and 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 particular application and design constraints imposed on the overall system.

[0171] The hardware and data processing devices used to implement the various example components, logic, logic blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed using general-purpose single-chip or multi-chip processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices (PLDs), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration. In some implementations, specific processes, operations, and methods may be performed by circuitry specific to a given function.

[0172] As noted 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 a method, operation, process, or algorithm disclosed herein, can be implemented as one or more modules of one or more computer programs. Such computer programs may include non-transitory processor-executable or computer-executable instructions encoded on one or more tangible processor-readable or computer-readable storage media for execution by or control the operation of a data processing device, including components of a device described herein. By way of example and not limitation, such storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage devices, magnetic disk storage devices or other magnetic storage devices, or any other medium usable for storing program code in the form of instructions or data structures. Combinations of the above should also be included within the scope of storage media.

[0173] Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the scope of the present disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with the present disclosure, the principles, and novel features disclosed herein.

[0174] Furthermore, various features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Thus, while features may be described above as acting in a particular combination and initially claimed as such, one or more features from the claimed combination can, in some cases, be deleted from the combination, and the claimed combination can be directed to a subcombination or a variation of the subcombination.

[0175] Similarly, although operations are shown in the figures in a particular order, this should not be understood as requiring that such operations be performed in the particular order or sequential order shown, or that all of the operations shown be performed, to achieve desirable results. Furthermore, the figures may generally illustrate one or more exemplary processes in the form of a flowchart or flow diagram. However, other operations not shown may be incorporated into the generally illustrated exemplary process. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the illustrated operations. In some situations, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the above-described implementations should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems may generally be integrated together in a single software product or packaged in multiple software products.

Claims

1. 1. A method for a power transmitter (PTx) in a wireless power system, comprising: performing a first power negotiation with the power receiver; communicating a proposed negotiation value to the power receiver as part of the first power negotiation; receiving a requested power negotiation value from the power receiver, the requested power negotiation value being based on the proposed negotiation value; indicating that the power transmitter accepts the requested power negotiation value; establishing a first guaranteed power based on acceptance of the requested power negotiation value; A method for a power transmitter (PTx) in a wireless power system, comprising:

2. The method of claim 1 , wherein the proposed negotiation value is based on a maximum guaranteed power that the power transmitter can negotiate with the power receiver based on general operating conditions of the power transmitter.

3. receiving a negotiation value request message from the power receiver; communicating the proposed negotiation value to the power receiver in response to the negotiation value request message; The method of any one of claims 1 to 2, further comprising:

4. transferring power from the power transmitter to the power receiver during a power transfer phase after the first power negotiation; receiving a power control message from the power receiver, the power control message indicating a requested power level; determining that the requested power level would cause the transmitter to exceed a current limit or a power limit of the transmitter or that the transmitter will not be able to meet the first guaranteed power established in the first power negotiation; initiating a second power negotiation to establish a second guaranteed power that replaces the first guaranteed power; 4. The method of claim 1, comprising:

5. The step of initiating the second power negotiation comprises: terminating power transfer to the power receiver; communicating a message to the power receiver to transition from the power transfer phase to a connection phase; The method of claim 4, comprising:

6. communicating a new proposed power negotiation value during the second power negotiation, the new proposed power negotiation value indicating the second guaranteed power that the power transmitter can support based on current operating conditions of the power transmitter; The method of claim 4 further comprising:

7. transferring power to the power receiver during a power transfer phase; detecting, based on measurements at the transmitter, that a misalignment condition is causing the transmitter to operate beyond a PTx limit or preventing the transmitter from meeting guaranteed power at the PTx limit; communicating a warning message indicative of the misalignment condition; A method for a power transmitter (PTx) in a wireless power system, comprising:

8. detecting the misalignment condition comprises: measuring a coupling coefficient (k-factor) between the power transmitter and the power receiver; determining that the k factor is not within a threshold range; The method of claim 7, comprising:

9. terminating power transfer to the power receiver; transitioning to a connection phase in response to detecting the misalignment condition or after the misalignment condition has persisted for a threshold time; The method of claim 7 further comprising:

10. detecting the misalignment condition comprises: verifying that no power transfer faults are indicated or identified by the power receiver or the power receiver that would cause the power transmitter to operate beyond the PTx limit or prevent the power transmitter from meeting the guaranteed power at the PTx limit; detecting the misalignment condition when a coupling coefficient (k-factor) is outside a threshold range and no power transfer fault is indicated or identified; 10. The method of any one of claims 7 to 9, comprising:

11. receiving a communication message from a power receiver, the communication message including a status field indicating a status of the power receiver; the status field includes at least one indicator selected from the group consisting of an indication of whether wired power is available to the power receiver, an indication of whether a protection switch is open or closed, and an indication of a fault status; A method for a power transmitter (PTx) in a wireless power system.

12. The method of claim 11 , wherein the communication message is a measurement (MEAS) message or a request (RQST) message, and the status field is included in the MEAS or RQST message.

13. A method for a power transmitter (PTx) in a wireless power system, comprising adjusting a communication carrier level of a communication signal during a power transfer phase with a receiver.

14. obtaining a value from the power receiver, the value indicating a measured voltage level of the communication signal received by the power receiver; adjusting the communication carrier level based on the value; The method of claim 13 further comprising during the power transfer phase:

15. detecting a change in alignment between a first communication unit of the power transmitter and a second communication unit of the power receiver; adjusting the communication carrier level based on the change in alignment; 15. The method of any one of claims 13 to 14, further comprising:

16. A power transmitter comprising a controller configured to perform any one of the methods of any one of claims 1 to 15.

17. performing a first power negotiation with the power transmitter; receiving proposed negotiation values ​​from the power transmitter as part of the first power negotiation; communicating a requested power negotiation value to the power transmitter, the requested power negotiation value being based on the proposed negotiation value; receiving an indication that the power transmitter accepts the requested power negotiation value; A method for a power receiver (PRx) in a wireless power system, comprising:

18. 18. The method of claim 17, wherein the proposed negotiation value is based on a guaranteed power that the power transmitter can guarantee to transfer to the power receiver or is based on the power transmitter's available power.

19. communicating a negotiation value request message to the power transmitter; receiving the proposed negotiation value from the power transmitter in response to the negotiation value request message; 19. The method of any one of claims 17 to 18, further comprising:

20. receiving power from the power transmitter during a power transfer phase after the first power negotiation; communicating a power control message to the power transmitter, the power control message indicating a requested power level; receiving a message from the power transmitter initiating a second power negotiation to establish a second guaranteed power to replace the first guaranteed power; 20. The method of any one of claims 17 to 19, further comprising:

21. receiving a new proposed power negotiation value from the power transmitter during the second power negotiation; the new proposed power negotiation value indicating the second guaranteed power that the power transmitter can support based on current operating conditions of the power transmitter; 21. The method of claim 20, comprising:

22. receiving power from a power transmitter during a power transfer phase; communicating a control message or a phase transition message to the transmitter; determining that the power transmitter did not process the control message or the phase transition message within an expected period of time; initiating a mitigation technique associated with a communication failure of the wireless power system; A method for a power receiver (PRx) in a wireless power system, comprising:

23. The mitigation technique comprises: opening a protection switch in a receiving circuit of the receiver during a final portion of an alternating current (AC) cycle of the wireless power signal; 23. The method of claim 22, comprising:

24. The mitigation technique comprises: opening the protection switch during a period of the AC cycle when the voltage is below a threshold level to disconnect a secondary coil of the receiver from other components of the receiver circuit; collecting basic operating power from the wireless power signal or communication signal during the communication period when communication is performed between the power transmitter and the power receiver; 24. The method of claim 23, comprising:

25. The mitigation technique presenting a user interface (UI) representation of the communication failure; powering off the power receiver; 25. The method of any one of claims 22 to 24, comprising:

26. 26. A power receiver comprising a controller configured to perform any one of the methods of any one of claims 17 to 25.

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