Wireless charging with a moving coil power transmitter

Abstract

This disclosure provides systems, methods and apparatuses for a Power Transmitter to inform the Power Receiver about the PTx type. The PTx type refers to the construction, capability, and / or other characteristics of the Power Transmitter. For example, the PTx type can indicate whether the Power Transmitter has a movable primary coil (e.g., a moving coil PTx) or has a stationary primary coil (e.g., a non-moving coil PTx). In some aspects, the PTx type can indicate whether the Power Transmitter has an electromagnetic ring for magnetic orientation or does not have an electromagnetic ring. According to aspects of this disclosure, the Power Transmitter and the Power Receiver can select a power profile or modify power transfer operations based on the PTx type. Some aspects enable a moving coil PTx to transfer wireless power using a magnetic power profile (MPP) mode.

Description

WIRELESS CHARGING WITH A MOVING COIL POWER TRANSMITTERRELATED APPLICATIONS

[0001] This application claims priority benefit of India Provisional Patent Application No. 202411031982 filed April 23, 2024, which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] This disclosure relates generally to wireless power and some aspects relate to protocol features and hardware aspects of a wireless power system including a Power Transmitter having a movable coil.DESCRIPTION OF RELATED TECHNOLOGY

[0003] A wireless power system includes a Power Transmitter (PTx) and a Power Receiver (PRx). The Power Transmitter can transfer energy to the Power Receiver using a magnetic resonance technique or a magnetic induction technique. In the magnetic resonance technique, a first power transfer coil (sometimes referred to as a primary coil) of the Power Transmitter generates a magnetic field that vibrates in a resonant frequency to transfer energy to a second power transfer coil (sometimes referred to as a secondary coil) of a Power Receiver designed to have the same resonant frequency. In the magnetic induction technique, the Power Transmitter transfers electrical energy using a phenomenon in which power is transferred from a first power transfer coil (sometimes referred to as a primary coil) of the Power Transmitter and a second power transfer coil (sometimes referred to as a secondary coil) of the Power Receiver using electromagnetic induction. The primary coil produces an electromagnetic field for power transfer (such as during a power transfer phase). The electromagnetic field induces a voltage in the secondary coil of the Power Receiver when the secondary coil is present in the electromagnetic field. The Power Receiver can provide the received power to a load or an energy storage unit (such as a battery). Example loads might include a motor, processor(s), a heating element, kitchen appliances, or electronics, among other examples.

[0004] Wireless power technologies continue to evolve as manufacturers and consumers develop new capabilities. Consumers continue to adopt wireless power technology for new applications and deployment scenarios. For example, newer wireless power transfer techniques are being developed to support improved magnetic coupling. Some advances in wireless power technology enable a wireless power system to increase the amount of power that can be transferred from a Power Transmitter to a Power Receiver.BRIEF SUMMARY

[0005] The systems, methods, and apparatuses of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0006] One aspect of this disclosure can be implemented as a method of a Power Transmitter (PTx) for wireless power transfer. The method includes detecting a Power Receiver and communicating, to the Power Receiver, a PTx type indication that indicates whether the Power Transmitter includes a movable primary coil.

[0007] Another aspect of this disclosure can be implemented as a method of a Power Receiver for wireless power transfer. The method includes communicating with a Power Transmitter and receiving, from the Power Transmitter, a PTx type indication that indicates whether the Power Transmitter includes a movable primary coil.

[0008] Another aspect of this disclosure can be implemented as a Power Transmitter for wireless power transfer. The Power Transmitter includes a movable primary coil capable of transmitting wireless power to a Power Receiver. The Power Transmitter includes a communication unit configured to communicate, to the Power Receiver, a PTx type indication that indicates that the Power Transmitter includes the movable primary coil.

[0009] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0010] Like reference numbers and designations in the various drawings indicate like elements. Note that the relative dimensions of the figures may not be drawn to scale.

[0011] FIG. 1A shows a general diagram of example wireless power transfer system that includes a Power Transmitter having a movable primary coil.

[0012] FIG. IB shows a pictorial diagram of example wireless power transfer systems.

[0013] FIG. 2 is a block diagram of an example wireless power system.

[0014] FIG. 3 shows a state diagram of a wireless power system.

[0015] FIG. 4 shows example power profiles of a wireless power system.

[0016] FIG. 5 shows a message flow diagram in which a Power Transmitter informs the Power Receiver about the Power Transmitter (PTx) type, such as whether the Power Transmitter includes a movable primary coil.

[0017] FIG. 6 shows example formats of a PTx type indication.

[0018] FIG. 7 shows an example identification packet including a PTx type indication.

[0019] FIG. 8 shows an example capabilities packet including a PTx type indication.

[0020] FIG. 9 shows an example moving coil capability packet including a PTx type indication.

[0021] FIG. 10 shows an example request message that a Power Receiver can use to request the PTx type indication.

[0022] FIG. 11 shows a message flow diagram in which a Power Transmitter communicates the PTx type indication as a feedback message in response to a specific request packet from the Power Receiver.

[0023] FIG. 12 shows a wireless power system in which a power transfer apparatus (such as Power Transmitter) includes an electromagnetic ring that can be selectively activated when using a magnetic power profile (MPP).

[0024] FIG. 13A shows a first example design for an electromagnetic ring in a power transfer apparatus.

[0025] FIG. 13B shows a second example design for an electromagnetic ring in a power transfer apparatus.

[0026] FIG. 14 shows a message flow diagram of a wireless power system in which the Power Transmitter includes an electromagnetic ring.

[0027] FIG. 15 shows a message flow diagram showing an abbreviated procedure to recover from disruption in power transfer.

[0028] FIG. 16 shows a Power Transmitter moving based on a movement of the Power Receiver.

[0029] FIG. 17 illustrates a block diagram of an example apparatus for use in a wireless power system.DETAILED DESCRIPTION

[0030] The following description is directed to certain implementations for the purpose of describing innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The described implementations can be implemented in any means, apparatus, system, or method for transmitting or receiving wireless power. Although the concepts and examples described in this document are based on wireless power transfer using example power profiles for magnetic induction, the concepts can apply to other types of deploymentsincluding other power profiles, communication protocols, or even other wireless power techniques.

[0031] As described previously, a wireless power system includes a Power Transmitter (PTx) and a Power Receiver (PRx). A Power Transmitter also may be referred to as a wireless power transmission apparatus. A Power Receiver also may be referred to as a wireless power reception apparatus. A Power Receiver includes a secondary coil configured to wirelessly receive power via inductive coupling with a primary coil of the Power Transmitter. A wireless power standard can support different power levels (such as 5 Watts (5W), 15W, 25W, etc.) using different power profiles. A power profile refers generally to a protocol and standard operation for a power transfer mode. As such, a power profile is based on the level of compatibility between a Power Transmitter and a Power Receiver. A first power profile (referred to as a baseline power profile (BPP)) can support up to 5W of wireless power transfer using an operating frequency in the range of 102 kilohertz (kHz) to 205 kHz (typically a Power Transmitter using BPP operates at 128 kHz). A second power profile (referred to as extended power profile (EPP)) introduces additional capabilities, such as extended protocol messages for improved coordination between the Power Transmitter and the Power Receiver, as well as higher power levels (such as up to 15W). A third power profile (referred to as magnetic power profile (MPP) mode) can operate at higher frequencies (such as 360 kHz) and can support higher power levels (such as 15W, 25W, etc.). For MPP, the Power Receiver and the Power Transmitter both typically have magnetic rings to improve the stable alignment of the two devices. MPP mode currently supports up to 15W and may continue to increase as the MPP mode is further developed.

[0032] In addition to different power levels and operating frequencies, each power profile is associated with a communication protocol, referred to as a baseline protocol for BPP, an extended protocol for EPP, and a magnetic protocol for MPP. Some protocol messages are common among the various protocols, while EPP and MPP are associated with changes to the baseline protocol. In some implementations, the Power Transmitter and the Power Receiver operate using the baseline protocol (for BPP) until they detect that both devices support another protocol (such as either the extended protocol (for EPP) or magnetic protocol (for MPP)).

[0033] A Power Transmitter can include a movable power transfer coil. In some examples of this disclosure, a “moving coil Power Transmitter” (or “moving coil PTx” or “MC PTx”) refers to a Power Transmitter that includes a movable power transfer coil (e.g., a movable primary coil). A moving coil PTx can alter the physical location of the primary coil based on the location of the Power Receiver within an operative environment of the Power Transmitter.In some implementations, the moving coil PTx detects the location of the Power Receiver using sensors, detection coils, a detection mat, or communication signals, among other examples. Current implementations of a moving coil PTx are based on the baseline protocol and the extended protocol. It is possible to use a moving coil PTx with the magnetic protocol (for MPP) - possible with or without a magnetic ring for alignment.

[0034] Some deployments of a moving coil PTx are intended for use in a vehicle (such as to charge a driver's mobile device while the vehicle is in motion). If the moving coil PTx has a magnetic ring, the moving coil PTx might maintain alignment with the Power Receiver during small vibrations or movements. However, it may be possible for a moving coil PTx to use magnetic protocol without having a magnetic ring. In such instances, a movement of the Power Receiver can temporarily disrupt communication and power transfer. It may take up to few seconds (example 2-5 seconds) or more for the Power Transmitter to move the primary coil to a location of the Power Receiver, reestablish communication, and resume power transfer. The delay can decrease charging efficiency and / or increase the time for wireless power charging. Absent the techniques of this disclosure, a Power Receiver might be unaware of whether a particular MPP-capable moving coil PTx has an electromagnetic ring for magnetic orientation / alignment or does not have an electromagnetic ring. Furthermore, selection of the appropriate power profile and protocol might depend on whether a Power Transmitter is a moving coil PTx or one that does not have a movable primary coil.

[0035] This disclosure provides systems, methods, and apparatuses for a Power Transmitter to inform the Power Receiver about the PTx type. The PTx type refers to the construction, capability, and / or other characteristics of the Power Transmitter. For example, the PTx type can indicate whether the Power Transmitter has a movable primary coil (e.g., a moving coil PTx) or has a stationary primary coil (e.g., a non-moving coil PTx). In some aspects, the PTx type can indicate whether the Power Transmitter has an electromagnetic ring or does not have an electromagnetic ring. According to aspects of this disclosure, the Power Transmitter and the Power Receiver can select a power profile or modify power transfer operations based on the PTx type.

[0036] A Power Transmitter can inform the Power Receiver about the PTx type using a variety of example techniques described in this disclosure. For example, the Power Transmitter can signal the PTx type in an identification packet, a capabilities packet, a moving coil capability packet, or a configuration packet, among other examples. In some implementations, the Power Receiver can transmit a request packet (such as a “get request” message) to request the PTx type and the Power Transmitter can signal the PTx type indication as a parameter of a response message. In some implementations, the Power Receiver cantransmit a specific request ("SRQ" message) to request a packet including a PTx type indication from the Power Transmitter. This disclosure provides several example formats and values for the PTx type indication.

[0037] In some implementations, a moving coil PTx can include an electromagnetic ring. The moving coil PTx can selectively energize the electromagnetic ring when an MPP-capable Power Receiver is in the operative environment of the moving coil PTx. The moving coil PTx can disconnect or disable the electromagnetic ring for a Power Receiver that does not support MPP. In some aspects, the PTx type can indicate whether the Power Transmitter has an electromagnetic ring for MPP operation.

[0038] Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. A Power Receiver can be made aware of the PTx type that is available to transfer power to the Power Receiver. The Power Receiver might alter power transfer operations or inform a user of the Power Receiver regarding the PTx type. By doing so, the Power Receiver can provide a better user experience.

[0039] Some examples of this disclosure refer to a Power Transmitter and a Power Receiver. Typically, a Power Transmitter operates in a power transmission mode to provide power to a Power Receiver. Similarly, a Power Receiver typically operates in a power reception mode to receive power from a Power Transmitter. However, in some implementations, a device can alternatively receive (in the power reception mode) or transmit (in the power transmission mode). For example, the device can be referred to as a “Power Transceiver,” a “wireless transmitter / receiver device,” a “Power Transmitter / Receiver,” or other terms to refer to the fact that the device is capable of operating in the power reception mode or the power transmission mode at various times. The device can operate as a Power Receiver when in vicinity of the Power Transmitter, and can operate as a Power Transmitter when in vicinity of a different Power Receiver. Thus, a same device (such as a smart phone or accessory) can be a Power Receiver to receive power from an external charger and can also be a Power Transmitter to provide power to another phone or accessory. Any of the features attributed to a “Power Transmitter” or a “Power Receiver” in this disclosure can be implemented by device (e.g., Power Transceiver) that operates in power transmission / reception modes.

[0040] FIG. 1A shows a general diagram of example wireless power system 100 that includes a Power Transmitter having a movable primary coil. The wireless power transfer system includes a Power Transmitter 102 and a Power Receiver 104. The Power Transmitter 102 includes a primary coil 110. The primary coil 110 is capable of transmitting wirelesspower 114 by generating a magnetic field that induces a voltage in a secondary coil 120 of the Power Receiver 104. The Power Receiver 104 includes a secondary coil 120 designed to receive the wireless power 114. The components of the Power Transmitter 102 and the Power Receiver 104 are described in further detail with reference to FIG. 2.

[0041] The Power Transmitter 102 in FIG. 1A is a moving coil PTx. As such, the Power Transmitter 102 includes a movable primary coil (e.g., the primary coil 110). The Power Transmitter 102 can adjust the location of the primary coil 110 in a variety of directions 198. In the example of FIG. 1A, Power Transmitter 102 can move the primary coil 110 along an X or Y axis (shown at arrows 130) in a plane that is parallel to an interface surface of the Power Transmitter 102. In some implementations, the location of the Power Receiver can be represented by coordinates (such as using a Cartesian coordinate geometry). In some implementations, the Power Transmitter 102 includes actuators or other components (not shown) to physically move a tray or board carrying the primary coil 110 to a target location. In some implementations, the power transmitter 102 can move the primary coil in three directions (such as X, Y, and Z axis).

[0042] The Power Transmitter 102 can use one of a variety of techniques to determine the target location for the primary coil 110. In some implementations, the Power Transmitter 102 selects the target location of the primary coil 110 based on the location of the secondary coil 120. The Power Transmitter 102 can determine the location of the secondary coil 120 using detection coils, sensors, communication signals, or other indications. For example, a detection mat (not shown) can be located at the interface surface on which the Power Receiver 104 is placed. The detection mat can include one or multiple detection coils. Using ping signals and measurements of impedance variation, the detection mat can localize the location of the Power Receiver on the interface surface.

[0043] In some aspects, the target location optimizes alignment and / or magnetic coupling between the movable primary coil 110 and the secondary coil 120. Alternatively, or additionally, Power Transmitter 102 can determine the target location based on calculations of power transfer efficiency during a power transfer phase. For example, the Power Transmitter 102 can continually or periodically determine an optimal target location based on measurements and / or calculations before or during power transfer. The Power Transmitter 102 can move the primary coil 110 to maintain coupling and power transfer efficiency above a threshold value.

[0044] In some implementations, when a Power Receiver becomes misaligned due to movement, the moving coil PTx suspends power transfer and enters a “cloak state.” whilethe moving coil PTx locates the Power Receiver. In the cloak state, the Power Transmitter pauses active power transfer while still maintaining a PTx-PRx link such that power transfer can be resumed any time without going through the entire start up flow and power negotiation stages. In the cloak state, the Power Transmitter detects the new location of the Power Receiver and moves the movable primary coil to a new target location based on the new location of the Power Receiver. Once the Power Transmitter identifies and confirms the Power Receiver at the new location, the Power Transmitter exits the cloak state and resumes power transfer.

[0045] FIG. IB shows a pictorial diagram of example wireless power transfer systems. In a first example 101A, the Power Transmitter 102 can be deployed in a kitchen environment and can be used for wireless power transfer to a cordless kitchen appliance 194 (such as a kettle, slow cooker, blender, toaster, or coffee machine, among other examples). In a second example 101B, the Power Transmitter 102 can be deployed in a home or vehicle and can be used for wireless power transfer to a device 193 (such as a mobile device, laptop or tablet computer, among other examples). In some implementation, a Power Transmitter 102 may be integrated in an apparatus that is portable in nature (such as a battery-powered portable hob for camping, as one example).

[0046] The Power Transmitter 102 can be deployed in a vehicle or other similar scenario in which movement or vibration is normally expected. When the Power Transmitter 102 includes a movable primary coil (such as described with reference to FIG. 1 A), the movements or vibrations can alter the alignment between the Power Transmitter 102 and a Power Receiver. Depending on the severity of misalignment, the Power Transmitter 102 and the Power Receiver may lose communication. For a first scenario (such as small displacement of less than / up to 2 millimeter (mm)), the Power Transmitter 102 and the Power Receiver 104 can maintain communication and power transfer. For a misalignment of greater than 2 mm displacement, it is possible to experience loss of communication and / or degradation of power transfer. It can be dangerous to continue transmitting wireless power after a misalignment or loss of communication. The risk can be higher when using MPP due to potentially higher levels of power (e.g., 15W) compared to BPP. After a loss of communication occurs, the Power Transmitter 102 ceases power transfer and re-establishes communication before resuming wireless power transfer. The process to resume wireless power transfer can take several seconds, during which time wireless power transfer is reduced or non-existent.

[0047] Some aspects of this disclosure provide protocol messages and packet formats to enable the Power Transmitter 102 to inform the Power Receiver whether the Power Transmitter has a movable primary coil. Some aspects of this disclosure provide hardwaredesigns to reduce the likelihood of misalignment caused by vibration or movement. Other aspects of this disclosure provide techniques to mitigate delay and loss of power transfer efficiency caused by a movement or misalignment.

[0048] FIG. 2 is a block diagram of an example wireless power system 200. The example wireless power system 200 includes a Power Transmitter 102 and a Power Receiver 104. The Power Transmitter 102 includes a primary coil 110 and a PTx controller 208. In some implementations, the primary coil 110 can also be referred to as a power transfer coil. The primary coil 110 is coupled to a Power Transmitter circuit 204 (sometimes also referred to as a power signal generator, a driver circuit, a driver, or a PTx tank circuit). The primary coil 110 may be a wire coil which transmits wireless power (which also may be referred to as wireless energy). The primary coil 110 may transmit wireless energy using an inductive or a resonant magnetic field. The Power Transmitter circuit 204 may include components (not shown) to prepare the wireless power. For example, the Power Transmitter circuit 204 may include one or more switches, drivers, series capacitors, rectifiers, inverters, or other components. In some implementations, the Power Transmitter circuit 204 includes an inverter and a PTx resonant tank circuit (which can be referred to as a “tank circuit” for brevity). In some implementations, the primary coil 110 and the Power Transmitter circuit 204 can be collectively referred to as a power transmitter unit 206. The PTx controller 208 may be implemented as a microcontroller, dedicated processor, integrated circuit, application specific integrated circuit (ASIC) or any other suitable electronic device.

[0049] A power supply 202 provides power to the power transmitter unit 206. In some implementations, the power supply 202 may convert alternating current (AC) power to direct current (DC) power. For example, the power supply 202 may include a converter that receives an AC power from an external power supply and converts the AC power to a DC power used by the Power Transmitter circuit 204. Alternatively, or additionally, a component (such as an inverter) of the Power Transmitter circuit 204 may convert the DC power to the AC power. The power supply 202 may be integrated as part of the Power Transmitter 102 or may be external to the Power Transmitter 102. In some implementations, the Power Transmitter 102 causes the power supply 202 to regulate the DC output voltage of the power supply 202. For example, the PTx controller 208 can set DC voltage of the power supply 202 based on information (such as a value indicating a requested power) received from the Power Receiver 104. The Power Transmitter 102 can receive power configuration information from the Power Receiver 104 and use the information to set one or more parameters (such as the DC voltage, current, or power output of the power supply 202). In some implementations, the PowerTransmitter 102 includes a DC-DC converter (not shown) between the power supply 202 and the Power Transmitter circuit 204 to control the variable DC output voltage.

[0050] The PTx controller 208 is connected to a communication interface 210. In the example of FIG. 2, the communication interface 210 is connected to a first communication coil 212. Alternatively, or additionally, the communication interface 210 can be coupled to the Power Transmitter circuit 204 or the primary coil 110. The term “PTx communication unit” refers to the communication components of the Power Transmitter 102, including the communication interface 210 and, when present, the first communication coil 212. In some implementations, the first communication unit may support short-range radio frequency communication, such as Near-Field Communication (NFC) or Bluetooth (BT). NFC is a technology by which data transfer occurs on a carrier frequency of 13.56 Megahertz (MHz). The PTx communication unit also may support any suitable communication protocol. The PTx communication unit may contain modulation and demodulation circuits to wirelessly communicate via the first communication coil 212. Alternatively, or additionally, the PTx controller 208 may use frequency, amplitude, current, or voltage modulation of a wireless power signal to communicate via an in-band communication link (not shown) that includes the primary coil 110. For example, the PTx communication unit can communicate using frequency shift keying (FSK) modulation applied to a signal of the Power Transmitter circuit 204 for generating the wireless power 248.

[0051] In the example of FIG. 2, an example apparatus 240 includes a Power Receiver 104 and other components (such as a converter 222, an energy storage unit 224, a load 242, a load controller 244, and / or a user interface 246). The Power Receiver 104 includes a secondary coil 120 (sometimes referred to as a “secondary coil” to distinguish from the primary coil of a Power Transmitter), a PRx tank circuit 216 (or “tank circuit”), a bridge circuit 220, a PRx controller 226, and a communication interface 228. The converter 222 can operate as a buck or boost converter or as a battery charger to alter the voltage of electricity being supplied to the energy storage unit 224 (when the Power Receiver 104 is being operated in a power reception mode) or being drawn from the energy storage unit 224 (when the Power Receiver 104 is being operated in a power transmission mode).

[0052] In some implementations, the apparatus 240 also includes a load controller 244 and a user interface 246 (such as a button, switch, touchpad, indicator, touch screen, or wireless local area network interface). The bridge circuit 220 can be a rectifier. In some implementations, the bridge circuit 220 is capable of operating as a rectifier or an inverter, and may be implemented as an active bridge. The PRx tank circuit 216 can include a capacitor or other components to enable the secondary coil 120 to receive the wireless power 248 duringthe power state. Although not shown, a small capacitor can be used before the bridge circuit 220 and a load capacitance can be used after the bridge circuit 220 to match impedance and to filter a high frequency component of the rectifier voltage. In accordance with aspects of this disclosure, the PRx tank circuit 216 includes a capacitance component that can alter the capacitance of the PRx tank circuit 216 depending on different power levels, power transmission or reception modes, or power profile, among other examples.

[0053] Although shown as different components, some components may be packaged or implemented in the same hardware. For example, in some implementations, the PRx controller 226 and the load controller 244 may be implemented as a single controller. The PRx controller 226, the load controller 244, the communication interface 228, or any combination thereof, may be implemented as a microcontroller, dedicated processor, integrated circuit, application specific integrated circuit (ASIC) or any other suitable electronic device. The communication interface 228 and the second communication coil 230 can be collectively referred to as a second communication unit. The second communication unit might also include a power harvester (not shown) that can harvest energy from the communication signals and provide harvested bias power to the PRx controller 226 or the load controller 244.

[0054] The PTx controller 208 may detect the presence or proximity of a Power Receiver 104. This detection may happen during a periodic pinging process of the communication interface 210. During the pinging process, the communication interface 210 supplies power to the communication interface 228 via communication signals 250 when the Power Receiver 104 is in proximity to the Power Transmitter 102. The communication interface 228 can send a reply signal back to the communication interface 210 to confirm that it is a Power Receiver. Prior to power transfer, a handshaking process may take place during which the PTx controller 208 may receive identification and configuration data, among other information, from the Power Receiver 104. The PTx controller 208 may control characteristics of wireless power it provides to the Power Receiver 104 based on the configuration data.

[0055] A PRx controller 226 may be operationally coupled to the bridge circuit 220 and the communication interface 228. The communication interface 228 may contain modulation and demodulation circuits to communicate via the second communication coil 230 or using in- band communication using load modulation on the wireless power. The term “PRx communication unit” refers to the communication components of the Power Receiver 104, including the communication interface 228 and, when present, the first second communication coil 230. The PRx controller 226 may communicate control or feedback information to the PTx controller 208 using the PRx communication unit. In some implementations, the PRxcommunication unit communicates with the PTx communication unit using short-range radio frequency communication, such as NFC. Alternatively, or additionally, the PRx communication unit may use load modulation to communicate via an in-band communication link (not shown) that includes the secondary coil 120. For example, the PRx communication unit can communicate using amplitude shift keying (ASK) modulation applied to a load modulation circuit of the PRx tank circuit 216.

[0056] A load controller 244 may be operationally coupled to the load 242 and the PRx controller 226 (or to the communication interface 228, coupling not shown in Fig. 2). The load controller 244 may detect changes to load states. The load controller 244 also may determine a load voltage reference and / or a power requirement of the load. The load controller 244 also may send load voltage references, load current, load power requirement and any other suitable information to the PRx controller 226 or the communication interface 228 for communication to the Power Transmitter 102. During a power state, the PRx controller 226 may additionally determine and provide one or more feedback information indicating a measured load voltage, load current, load power requirement, and power available to the load 242. In some feedback messages, the feedback information may include a reference voltage indicating a required voltage for the load 242. In some feedback messages, the feedback information may indicate an error in the output voltage of the load 242. In some feedback messages, the feedback information may include the required power for the load. Although the PRx controller 226 and load controller 244 are shown separately, they may be included in the same component of the Power Receiver 104.

[0057] Some appliances are equipped with safety features, such as a disconnect switch 214, that are operated in conjunction with the operating states. For example, the disconnect switch 214 might be maintained in an open position to prevent the flow of current to the load 242 when the Power Receiver 104 is in a pre-power state (such as a ping phase, a configuration phase, and / or a negotiation phase). Before transitioning to the power state (also referred to as a power transfer phase), the PRx controller 226 might cause the disconnect switch 214 to move to a closed position to connect the secondary coil 120 to the PRx tank circuit 216. In an emergency condition (such as excessive voltage or current), the PRx controller 226 might open the disconnect switch 214 to prevent damage to the load 242 or other components of the Power Receiver 104 or the apparatus 240. After the disconnect switch 214 is closed, the PRx controller 226 can communicate a message to the PTx controller 208 to cause the wireless power system to transition to the power state. Alternatively, or additionally, the PRx controller 226 can communicate a power request to begin the transmission of the wireless power 248.

[0058] FIG. 3 shows a state diagram 300 of a wireless power system. The state diagram 300 illustrates the operating states in which the wireless power system may operate. When a Power Receiver is placed within an operating volume on the interface surface of a Power Transmitter, the two start to communicate to configure settings for the wireless power transfer. There are four operating states shown in FIG. 3: a ping phase 302 (sometimes also referred to as a ping state), a configuration phase 304 (sometimes referred to as an identification phase), a negotiation phase 306, and a power transfer phase 308 (sometimes referred to as a power transfer state). The ping phase 302, the configuration phase 304, and the negotiation phase 306 can collectively be referred to as pre-power states. A technical specification may define how the Power Transmitter and Power Receiver can transition between the operating states. For example, the wireless power system typically begins in the ping phase 302 until the Power Transmitter detects a Power Receiver, moving it to the configuration phase 304. In the configuration phase 304, the Power Transmitter establishes communication and receives the identification information of the Power Receiver and its static configuration data. In the negotiation phase 306 the Power Transmitter and Power Receiver exchange information to agree and adjust parameters related to wireless power transfer. In the power transfer phase 308, the Power Transmitter transmits wireless power to the Power Receiver. The Power Receiver may occasionally or periodically communicate status or feedback control messages to the Power Transmitter during the power transfer phase 308. The system can move to a reinitialization state (not shown) as needed to reinitialize or return to the ping phase 302 when communication, powering, or other activities are no longer taking place. Each of the operating states are briefly described herein for reference.

[0059] In the ping phase 302, the Power Transmitter tries to establish communications with a Power Receiver. The Power Receiver may be just placed on the interface surface or may not be present during this operating state. The Power Transmitter may attempt to communicate or detect the presence of the Power Receiver. For example, the Power Transmitter may use an analog ping, out-of-band communication (such as NFC), a digital ping, impedance change detection, or any combination thereof, to determine that a compatible Power Receiver is present. In some implementations, the Power Transmitter transmits different types of ping signals to detect different types of Power Receivers. For example, the Power Transmitter can transmit a first type of digital ping using 128 kHz for BPP or EPP and a second type of digital ping using 360 kHz for MPP. The Power Transmitter might alternate between the first type and second type of digital ping. Alternatively, the Power Transmitter can initially transmit the first type of digital ping and then transmit the second type of digital ping after receiving a first ping response from the Power Receiver in response to the first typeof digital ping. Once the wireless power system determines that a Power Receiver is present (such as by confirming NFC communication or receiving a ping response or other communication from the Power Receiver in response to a digital ping), the wireless power system may transition to the configuration phase 304.

[0060] In the configuration phase 304, the Power Receiver may establish communication with the Power Transmitter and send identification information (such as an identification packet 310) to the Power Transmitter. In some implementations, the Power Transmitter may retrieve static configuration information from the Power Receiver via the NFC communication. In some implementations, the Power Transmitter can also transmit an identification packet to the Power Receiver. The Power Transmitter and the Power Receiver may use the identification information to verify that they both use compatible versions of a technical specification or protocol for wireless power transfer. The Power Transmitter and Power Receiver may communicate basic settings or communicate regarding their respective capabilities. From the configuration phase 304, the wireless power system may transition to the negotiation phase 306.

[0061] In the negotiation phase 306, the Power Transmitter and the Power Receiver may exchange further communications (such as capabilities and / or configuration messages 350) to negotiate the parameters that govern the power transfer phase 308. For example, a power negotiation can occur during the negotiation phase 306. After negotiating the parameters, the Power Transmitter may be prepared to transfer wireless power and the Power Receiver may be prepared to receive the wireless power. The Power Transmitter may wait for a request or command from the Power Receiver before transitioning to the power transfer phase 308.

[0062] In the power transfer phase 308, the Power Transmitter generates a wireless power signal to transfer power to the Power Receiver via inductive or resonant coupling. The Power Transmitter generates the wireless power using a frequency, a voltage, and other operating points associated with the amount of power negotiated during the negotiation phase 306.

[0063] From the power transfer phase 308, the Power Transmitter and the Power Receiver may transition back to the negotiation phase 306 until a next power transfer operation is needed. Alternatively, the wireless power system might transition to the ping phase 302. In some implementations, if the Power Transmitter determines that the Power Receiver is moved, that the Power Receiver is no longer present in an operating environment of the Power Transmitter, or that a foreign object has been introduced to the operating environment, the Power Transmitter might transition to a reinitialization state (not shown) or any of the other pre-power states.

[0064] In accordance with aspects of this disclosure, the Power Transmitter informs the Power Receiver about the PTx type of the Power Transmitter. For example, the Power Transmitter can communicate a PTx type indication in an identification packet 310, a capabilities or configuration message 350, or via another packet. In some implementations, the Power Transmitter communicates the PTx type indication during the configuration phase 304 or the negotiation phase 306. The PTx type indication can indicate, for example, whether the Power Transmitter is a “moving coil PTx” that has a movable primary coil. Additionally, in some aspects, the PTx type indication can indicate that the Power Transmitter is capable of operating in an MPP mode using the movable primary coil and / or whether the Power Transmitter has an electromagnetic ring for magnetic alignment in the MPP mode.

[0065] FIG. 4 shows example power profiles 400 of a wireless power system. The example power profiles 400 include a baseline power profile (BPP) 402, an extended power profile (EPP) 404, and a magnetic power profile (MPP) 406. Each power profile is associated with a protocol, supported power levels, and design features. Table 1 summarizes some example differences.Feature BPP EPP MPP5, 8, 12, or 15 15 W (possibly 25PTx supported power level 5 WW W)< 15 2 (possibly < PRx load power level < 5 W < 15 W25 W)Nominal ping / operating128 kHz 128 kHz 360 kHz frequency baseline extendedProtocol magnetic protocol protocol protocolTable 1.

[0066] A technical specification defines the communications physical layer, message format, and order of communications for each protocol. For example, the magnetic protocol is based on a communications physical layer that uses in-band modulation via a power signal. For the magnetic protocol communications physical layer, the Power Transmitter uses FSKmodulation for PTx communications and the Power Receiver uses ASK modulation for PRx communications.

[0067] According to a current version of the technical specification for MPP, the Power Transmitter and the Power Receiver both include a permanent magnetic ring for physical alignment of the devices. Thus, the Power Transmitter and the Power Receiver can operate in a first type of MPP operation 408 in which the Power Transmitter includes a permanent magnetic ring for alignment. According to aspects of this disclosure, a Power Transmitter having a movable primary coil might not include a permanent magnetic ring. For example, the technical specification for MPP might evolve such that the permanent magnetic ring is optional for some types of Power Transmitters, such as a moving coil PTx. In a second type of MPP operation 410, the Power Transmitter is a moving coil PTx that implements the magnetic protocol for MPP but which might not have a permanent magnetic ring. The second type of MPP operation 410 can also be referred to as “MPP with a moving coil PTx,” “MPP with MC PTx,” “movable coil MPP,” “MC MPP,” or other similar terms. In some implementations, a moving coil PTx can include an electromagnetic ring for alignment, such as described with reference to FIG. 12 through FIG. 13B. Thus, for a third type of MPP operation 412, the Power Transmitter can use a movable coil in coordination with an electromagnetic ring for alignment. The third type of MPP operation 412 can also be referred to as “moving coil electromagnetic ring MPP,” “MC-EM MPP,” or any suitable term to refer to a combination of movable primary coil and electromagnetic ring.

[0068] As shown in FIG. 4, a Power Transmitter can implement the magnetic protocol for MPP 406 while having slightly different mechanical or functional capabilities based on the Power Transmitter design. Power Transmitter design refers to whether the Power Transmitter has a movable primary coil, whether it has a permanent magnet, and / or whether it has an electromagnetic ring. According to aspects of this disclosure, the Power Transmitter can communicate a PRx type indication. The PRx type indication can inform the Power Transmitter of the type of MPP operation 408, 410, or 412 supported by the Power Transmitter. Alternatively, or additionally, the PRx PTx type indication can refer to aspects of the Power Transmitter design such that the Power Receiver can determine the possible MPP operational capabilities based on the Power Transmitter design.

[0069] FIG. 5 shows a message flow diagram in which a Power Transmitter informs the Power Receiver about the PTx type, such as whether the Power Transmitter includes a movable primary coil. At an initial ping phase (such as ping phase 302 of FIG. 3), the Power Transmitter 102 can communicate a digital ping 502 and receive a ping response from the Power Receiver 104. following the ping phase, the Power Receiver 104 can transmitidentification and configuration information 504. For example, the identification and configuration information 504 can indicate that the Power Receiver 104 supports an MPP mode. In some implementations, the Power Transmitter 102 might perform another digital ping (not shown) according to the magnetic protocol. For example, if the digital ping 502 is a 128 kHz digital ping for BPP mode, the Power Transmitter 102 might perform a 360 kHz digital ping for the MPP mode after receiving the identification and configuration information 504 from the Power Receiver 104. Alternatively, if the digital ping 502 is a 360 kHz digital ping for the MPP mode, the ping response from the Power Receiver 104 can implicitly indicate that the Power Receiver 104 supports the MPP mode. Similarly, the 360 kHz digital ping for the MPP mode (e.g., either at digital ping 502 or following the identification and configuration information 504) can implicitly inform the Power Receiver 104 that the Power Transmitter 102 supports the MPP mode. Once the Power Transmitter 102 and the Power Receiver 104 have determined that they both support MPP, they implement the message formats and communication flow defined for the magnetic protocol. Alternatively, the Power Transmitter 102 and the Power Receiver 104 can implement the baseline protocol (for BPP) or the extended protocol (for EPP) based on which power profile is mutually supported.

[0070] At block 540, the Power Transmitter 102 can inform the Power Receiver 104 about the PTx type according to aspects of this disclosure. For example, the PTx type can indicate whether the Power Transmitter 102 is a moving coil PTx. The Power Transmitter 102 can communicate a PTx type indication 550 via a PTx communication 544 from the Power Transmitter 102 to the Power Receiver 104. In some implementations, the PTx communication 544 is in response to a previous PRx communication 542 (such as a request message).

[0071] At block 560, the Power Receiver 104 optionally modifies its operations based on the PTx type. For example, if the PTx type indicates that the Power Transmitter 102 is a moving coil PTx, the Power Receiver 104 might adjust the power level, power profile, or communication protocol delay tolerance. In some implementations, the Power Receiver 104 can display or provide an indication via a user interface to inform a user regarding the PTx type. The Power Receiver 104 might adjust or calculate an estimated amount of time for the Power Receiver 104 to charge a battery, where the estimated amount of time depends on the PTx type. For example, the Power Receiver 104 can consider past charging average times based on a pattern of charging using the PTx type and inform the user about estimated amount of time for a particular PTx type. As an example, the estimated amount of time for charging when using a moving coil PTx without a permanent magnet or electromagnetic ring might be longer compared to power transfer using a Power Transmitter that has a permanent orelectromagnetic ring. In some implementations, when the PTx type indication informs the Power Receiver 104 that the Power Transmitter 102 does not an electromagnetic ring, the Power Receiver can warn the user of low charging rate when frequent movement is experienced or expected. By averaging the power drawn, the power request can also indicate the user the charging time.

[0072] In some implementations, at block 560, the Power Receiver 104 might implement protocol changes specified in the magnetic protocol for use when the Power Receiver 104 is latched to a moving coil PTx. For example, the magnetic protocol might specify an additional protocol byte or message format that is specific to MPP by a moving coil PTx. After completing a negotiation phase (not shown), the Power Transmitter 102 can perform wireless power transfer 570 in a power transfer phase.

[0073] Although examples of this disclosure are based on a PTx type indication 550 communicated via a PTx communication 544, other techniques are possible. For example, shown at block 530, the Power Receiver 104 might detect a characteristic of the operative environment that is indicative that the Power Transmitter 102 is a moving coil PTx. As an example, the Power Receiver 104 can include a hall sensor or other sensor capable of detecting the presence of a magnetic ring or electromagnetic ring of the Power Transmitter 102. Alternatively, or additionally, the Power Receiver 104 can determine that the Power Transmitter 102 is a moving coil PTx based on a pattern for a ping (such as the digital ping 502), a configurable setting in a memory of the Power Receiver 104, or a machine learning model that detects a movable primary coil based on a historical pattern of wireless power signal adjustments, among other examples.

[0074] FIG. 6 shows example formats of a PTx type indication 550. In some implementations, the PTx type indication 550 can include a first value (for a moving coil PTx) 602 or a second value (for a non-moving coil PTx) 604. Alternatively, or additionally, the PTx type indication 550 can include a lookup value referring to MC capability and power profile 606. Tables 2 and 3 show example values for various PTx type indications.Value Meaning0 non-moving coil PTx1 moving coil PTx (e.g., with or without MPP support)Table 2Value Meaning0 non-moving coil PTx1 moving coil PTx not supporting MPP moving coil PTx supporting MPP without magnetic ring (e.g., “MC 2MPP”) moving coil PTx supporting MPP with electromagnetic ring (e.g., 3“MC-EM MPP”)Table 3

[0075] The examples in Tables 2 and 3 are provided as non-limiting examples. Any variety of values and ascribed meanings can be conceived for the PTx type indication. Furthermore, the quantity of bits and additional information conveyed by the PTx type indication can vary depending on implementation in a technical specification or use case. For example, the PTx type indication can be as small as a single bit in a PTx communication. Alternatively, the PTx type indication can be 2, 4, 8, or other quantity of bits. In some implementations, the PTx type indication can be combined with other information such that a value in a lookup table can represent an option for the other information as well as whether the Power Transmitter is a moving coil PTx. A potential technical advantage of the example in Table 3 is that the PTx type indication can inform the Power Receiver whether the moving coil PTx has an electromagnetic ring. When the Power Receiver is informed that the moving coil PTx does not have an electromagnetic ring, the Power Receiver can warn the user of a low charging rate, such as when frequent movement is experienced or expected (as in a vehicle).

[0076] In some implementations, the magnetic protocol can specify the size, format, and location of the PTx type indication 550 within a defined packet format. FIG. 7 through FIG. 9 shows some example packet formats that can include a PTx type indication 550. The example packets in FIG. 7 and FIG. 9 are examples of the PTx communication 544 described with reference to FIG. 5.

[0077] FIG. 7 shows an example Power Transmitter identification packet 700 including a PTx type indication 550. The Power Transmitter identification packet 700 is based on anextended Power Transmitter identification (XID) packet defined for the magnetic protocol. The Power Transmitter communicates the XID packet to the Power Receiver to provide information to help identify the Power Transmitter. For example, the XID packet includes a device identifier that identifies the Power Transmitter.

[0078] According to the example in FIG. 7, XID packet can include the PTx type indication 550 in any of the following locations in the XID packet:• Bo Byte -Bit ba to bo;• Bi Byte - Bit b? to bo;• Ba Byte -Bit b? to bo;• Ba Byte -Bit b? to bo; or• B4 Byte . Bit b?.

[0079] FIG. 8 shows an example capabilities packet 800 including a PTx type indication 550. The capabilities packet 800 is based on an Extended Power Transmitter Extended Capabilities (ECAP) packet defined for the magnetic protocol. The Power Transmitter communicates the ECAP packet to the Power Receiver to provide information about the Power Transmitter's capabilities. For example, the ECAP packet includes a potential load power (indicating the maximum load power that the Power Transmitter supports), a negotiable load power (indicating a maximum available power that the Power Receiver is allowed to negotiate), a power limit reason, a data stream buffer size, and indication of the maximum number of the concurrent data streams that the Power Transmitter can handle.

[0080] According to the example in FIG. 8, ECAP packet can include the PTx type indication 550 in any of the following locations in the ECAP packet:• Bo Byte -Bit bs to bo;• Bi Byte - Bit b? to b2;• B3 Byte > Bit b? to b2;• B5 Byte .Bit b? to b4;• Be Byte . Bit b? to be;• B7 Byte > Bit b? to b4; or• Bs Byte -Bit b? to b4.

[0081] FIG. 9 shows an example packet 900 including a PTx type indication 550. For example, the packet 900 can be a new packet defined for the magnetic protocol, and can be referred to by any suitable name and / or acronym for the new packet 900. In the example of FIG. 9, the new packet 900 is referred to as an “Extended Power Transmitter Moving Coil Packet” or “PTx MC packet.” The PTx MC Packet can also be referred to by other names,such as a PTx moving coil MPP capability packet or PTx MC MPP packet. According to the example in FIG. 9, the PTx type indication 550 can be included in a “moving coil status” or “moving coil type” field of the new packet 900. In one example, the moving coil status field is populated with a first value (such as “00”) to indicate the Power Transmitter is not a moving coil PTx. The moving coil status field is populated with a second value (such as “FF”) to indicate the Power Transmitter is a moving coil PTx. Alternatively, the moving coil status field can be populated with any of the example values representing the meanings described with reference to FIG. 6 (such as Tables 2 and 3).

[0082] FIG. 10 shows an example request packet 1000 that a Power Receiver can use to request the PTx type indication. The request packet 1000 is an example of a PRx communication 542 (as described in FIG. 5) that triggers the Power Transmitter to communicate a packet that includes the PTx type indication. The example request packet 1000 is based on a “get request" (GET) packet in the magnetic protocol. In some implementations, the GET packet can include a request indicator 1052 in a specified location, such as Bo Byte > Bit b? to bo or in Bi Byte > Bit b? to bs. Alternatively, or additionally, the parameter field of the GET packet can include a parameter value 1054 that requests the PTx communication having the PTx type indication. For example, a parameter value 1054 can be a first value (e.g., “0”) to request an XID packet, a second value (e.g., “4”) to request an ECAP packet, or a different value (e.g., “1” or “8”) the represents a request for a PTx MC Packet (such as the new packet 900 described with reference to FIG. 9).

[0083] FIG. 11 shows a message flow diagram in which a Power Transmitter communicates the PTx type indication as a feedback message in response to a specific request packet from the Power Receiver. In the magnetic protocol, the Power Receiver 104 can communicate a specific request (SRQ) packet for a simple request of limited information. For example, the SRQ can include a request field and a parameter field. According to aspects of this disclosure, the Power Receiver 104 can communicate a specific request 1142 (referred to as a specific request to determine a moving coil (MC) MPP capability, or “SRQ / MCMPP”). The specific request 1142 can cause the Power Transmitter 102 to communicate a response 1144. Typically, a response to an SRQ packet includes simple feedback (such as an acknowledgement (ACK) or a non-acknowledgement (NAK). In the example of FIG. 11, when the Power Transmitter 102 receives the SRQ / MCMPP packet, the Power Transmitter 102 can respond with a first value (e.g., “ACK”) if the Power Transmitter 102 is a moving coil PTx that supports MPP or a second value (e.g., “NAK”) if the Power Transmitter 102 is not a moving coil PTx or does not support MPP.

[0084] FIG. 12 shows a wireless power system in which a power transfer apparatus (such as Power Transmitter) includes an electromagnetic ring that can be selectively activated when using a magnetic power profile (MPP). The Power Transmitter 102 includes an electromagnetic ring 1210 around the primary coil 110. The electromagnetic ring 1210 can be designed to mimic a same or similar structure that would previously have been constructed using a permanent magnetic ring in a traditional MPP Power Transmitter. For example, the electromagnetic ring 1210 can include a notch 1216 for rotational alignment. Furthermore, the electromagnetic ring 1210 can have a radius or polarity design specified for MPP. For example, the electromagnetic ring 1210 can have an outer polarity 1212 and an inner polarity 1214 according to a technical specification for MPP operation. Reference 1236 illustrates an example polarity of the electromagnetic ring 1210 when the electromagnetic ring 1210 is energized. When the electromagnetic ring 1210 is energized, the electromagnetic ring 1210 exhibits the same or similar magnetic properties of a permanent magnetic ring. However, when the electromagnetic ring 1210 is not energized, the electromagnetic ring 1210 can be an isolated / disconnected circuit without the properties of a magnet. Thus, when operating in an MPP mode, the electromagnetic ring 1210 is energized to mimic a magnetic ring and when operating in BPP or EPP mode, the electromagnetic ring 1210 is disconnected to prevent magnetic interference to a wireless power signal.

[0085] The Power Receiver 104 includes a corresponding magnetic ring 1220. The magnetic ring 1220 can include a notch 1226, radius, inner polarity 1222, and outer polarity 1224 according to a technical specification for MPP operation. Reference 1232 illustrates an example polarity of the magnetic ring 1220. The inner and outer polarities of the electromagnetic ring 1210 and the magnetic ring 1220 are opposite to that the rings 1210 and 1220 attract each other (shown at reference 1234). When the electromagnetic ring 1210 is energized and in proximity to the magnetic ring 1220, the magnetic properties of the rings 1210 and 1220 facilitate a magnetic alignment 1230. The rings 1210 and 1220 can also be referred to as orientation magnets. In addition to providing rotational alignment and magnetic field effect, the orientation magnets can provide a magnetic force to maintain physical placement of the secondary coil 120 in relation to the primary coil 110.

[0086] In instances where a device (such as a Power Transmitter / Receiver) can operate in power transmission mode (as a Power Transmitter) or a power reception mode (as a Power Receiver), such device can include an electromagnetic ring (such as the electromagnetic ring 1210). Furthermore, a controller of the Power Transmitter / Receiver can alter the polarity of the inner / out rings by reversing the direction of current applied to the electromagnetic ring.

[0087] The are a variety of options for the design and operation of the electromagnetic ring. FIG. 13A and FIG. 13B include some example options. Further detail and options are described in India Provisional Patent Application No. 202311082327, filed December 4, 2023, and entitled “ALIGNMENT FOR WIRELESS POWER TRANSFER USING ELECTROMAGNETS,” the contents of which are hereby incorporated in this description.

[0088] FIG. 13A shows a first example design 1302A for an electromagnetic ring in a Power Transmitter. The Power Transmitter includes a primary coil 110 and electromagnetic ring 1210 in or on a tray 1342 or board. In some implementations, the tray 1342 can include a printed circuit board (PCB). The electromagnetic ring 1210 is constructed using two rings of ferrite arrays 1310. When the electromagnetic ring 1210 is energized, the first ring has the magnetic properties of the inner polarity 1222 and a second ring has the magnetic properties of the outer polarity 1224. A wire 1356 is wound around ferrite portions of the two rings of ferrite arrays 1310. The wire 1356 is wound in a first direction around the ferrite portions of an outer ring and a wound in a second direction around the ferrite portions of the inner ring. Reference 1352 illustrates the wire 1356 wound in different directions around the inner and outer ring ferrite portions. When the wire 1356 is energized (e.g., current is applied to the wire 1356), the ferrite portions exhibit magnetic properties. The magnetic polarity of each ferrite portion depends on the direction that wire 1356 is wound around the ferrite portion. Thus, by winding the wire 1356 around the ferrite portions of the outer ring in a same first direction and around the ferrite portions of the inner ring in a same second direction, the two rings of ferrite arrays 1310 can create the inner polarity 1222 and the outer polarity 1224.

[0089] The tray 1342 includes the primary coil 110 and the electromagnetic ring 1210. The primary coil 110 can be referred to as a movable primary coil because the tray 1342 is movable within an area 1348 of the Power Transmitter. For example, the tray 1342 can be positioned along an X and Y axis of a plane forming the area 1348. In some implementations, when a Power Transmitter determines that a Power Receiver (not shown) is present in an interface surface and supports MPP, the Power Transmitter can energize the electromagnetic ring 1210. The electromagnetic ring 1210 can magnetically align to a corresponding magnetic ring of the Power Receiver, thereby aligning the primary coil 110 to a secondary coil of the Power Receiver.

[0090] FIG. 13B shows a second example design 1302B for an electromagnetic ring in a Power Transmitter. The features of FIG. 13B are the same as described with reference to FIG. 13A except for a different construction of the electromagnetic ring 1210. In FIG. 13B, the electromagnetic ring 1210 is constructed using ferrite arrays in single layer 1311. Each ferrite array can be referred to as an electromagnet. A wire 1356 is wound around a centerferrite portion 1358 of the electromagnet such that the electromagnet generates an alternating pole magnetic property when current is applied to the wire 1356. Reference 1354 shows the wire 1356 wound around the center portion 1358 such the electromagnetic force generates a first polarity in a first direction and a second polarity in a second direction. Notice that the resulting polarities in reference 1354 of FIG. 13B and reference 1352 of FIG. 13A have a same polarity orientation facing an interface surface (e.g., top side of references 1354 and 1352).

[0091] The example designs 1302A and 1302B in FIG. 13A and FIG. 13B, respectively, are two examples of designs to implement an electromagnetic ring on the Power Transmitter. A Power Transmitter can implement other designs to implement an electromagnetic ring. A potential technical advantage of an electromagnetic ring is that the Power Transmitter can latch to a Power Receiver to mitigate or prevent misalignment or movement conditions that might otherwise occur. For example, when the wireless power system is implemented in a vehicle, the electromagnetic ring can prevent a movement of Power Receiver that might otherwise cause a loss of communication and need to restart the magnetic protocol. However, the electromagnetic ring is appropriately suited for use with a Power Receiver that supports MPP. The presence of a magnetic ring (e.g., permanent magnetic ring or energized electromagnetic ring) can disrupt operation for a Power Receiver that does not support MPP (such as a Power Receiver that does not have a corresponding magnetic ring). In such instances, the magnetic ring can saturate the power transfer coils and interrupt or reduce power transfer. With non-energized electromagnetic ring, a moving coil PTx can still support a high power level (e.g., 15W) using EPP for an EPP-compatible Power Receiver. Thus, the electromagnetic ring enables greater power transfer efficiency by tailoring the Power Transmitter to the MPP or non-MPP capabilities of the Power Receiver.

[0092] FIG. 14 shows a message flow diagram 1400 of a wireless power system in which the Power Transmitter includes an electromagnetic ring. The message flow begins with a digital ping 502 and identification and configuration information 504 as described with reference to FIG. 5. In the example of FIG. 14, the Power Transmitter 102 and the Power Receiver 104 are initially operating in a non-MPP mode 1426 (such as BPP or EPP). At block 1428, when operating in BPP mode or EPP mode, the Power Transmitter 102 refrains from energizing the electromagnetic ring.

[0093] In FIG. 14, the Power Transmitter 102 and the Power Receiver 104 discover that both are capable of operating using an MPP mode MPP protocol 1460. For example, at block 1440, the Power Transmitter 102 can inform the Power Receiver 104 that the Power Transmitter 102 has a movable primary coil and an electromagnetic ring for MPP. The Power Transmitter102 can communicate a PTx communication 1444 to the Power Receiver 104 indicating a PRx type. The PTx communication 1444 can be a response to a previous PRx communication 1442. The operations at events 1440, 1442, and 1444 are similar to the events 540, 542, and 544 described with reference to FIG. 5. Based on a determination that they both support MPP, the Power Transmitter 102 and the Power Receiver 104 can change from the non-MPP mode to an MPP mode 1460. At block 1468, the Power Transmitter 102 energizes the electromagnetic ring when operating in the MPP mode.

[0094] In some implementations, the Power Transmitter 102 can energize the electromagnetic ring after detecting a first loss of communication with the Power Receiver 104 due to a movement or misalignment event. For example, the Power Transmitter 102 can determine that a vibration or movement of the Power Transmitter has caused a loss of communication and can energize the electromagnetic ring to quickly move the primary coil back to a location that is magnetically aligned to a secondary coil of the Power Receiver 104.

[0095] FIG. 15 illustrates a message flow diagram 1500 showing an abbreviated procedure to recover from disruption in power transfer. The message flow begins with a digital ping 502 and identification and configuration information 504 as described with reference to FIG. 5. The identification and configuration information 504 includes identification information that uniquely identifies the Power Receiver 104, among other data. The Power Transmitter 102 and the Power Receiver 104 optionally perform a power negotiation 1516 to negotiate settings for a power transfer phase 1518. The Power Transmitter 102 can store the settings in a local storage 1510 (also referred to as a memory) of the Power Transmitter 102. For example, the settings can be stored in association with the identification information of the Power Receiver 104, a session identification number, or other index that is commonly known to the Power Transmitter 102 and the Power Receiver 104. In some implementations, the Power Transmitter 102 can store a location (such as a coordinate) of the Power Receiver 104 as a reference for calculating the shortest path to a new location, as further described with reference to FIG. 16.

[0096] At some point the Power Transmitter 102 detects loss of communication 1519. For example, the loss of communication 1519 can occur as a result of the Power Transmitter 102 or the Power Receiver 104 moving and / or experiencing a misalignment between their respective primary coil and secondary coil. At block 1522, the Power Transmitter 102 detects the Power Receiver 104. In some implementations, the Power Transmitter 102 can move a movable primary coil to a new target location based on a new detected location of the Power Receiver 104 in the interface surface. The Power Transmitter 102 can re-establish a communication channel with the Power Receiver 104 when the movable primary coil is at thenew target location. The Power Transmitter 102 obtains identification information 1506 from the Power Receiver 104. Using the identification information (or a session identification number or other index) the Power Transmitter 102 retrieves (shown at arrow 1524) the stored settings from the local storage 1510. The Power Transmitter 102 can perform an abbreviated procedure 1526 in the magnetic protocol to resume power transfer. The abbreviated procedure 1526 can reduce the amount of time needed to recover communication and power transfer following a mo vement / mis alignment event. In some implementations, the abbreviated procedure 1526 might include an abbreviated authentication, configuration, and negotiation message exchange compared to a full procedure for those items in the magnetic protocol. Following the abbreviated procedure 1526, the Power Transmitter 102 and the Power Receiver 104 can optionally perform a new power negotiation 1516. Thereafter, the Power Transmitter 102 resumes power transfer 1518 to the Power Receiver 104.

[0097] FIG. 16 shows a Power Transmitter moving based on a movement of the Power Receiver. Initially, the Power Receiver 104 is located at a first PRx location 1602 (which may be referenced by a first coordinate, such as Xi, Y i). The Power Transmitter 102 is located at an initial location 1608 suitable to provide power to the Power Receiver 104. The Power Transmitter 102 might store the coordinate of the first PRx location 1602 or the initial location 1608 in a local storage (e.g., memory).

[0098] At some point the Power Receiver 104 may move to a second PRx location 1604, such as due to a movement of a vehicle or bumping an environment of the wireless power system. A detection mat (not shown) can detect that the Power Receiver 104 is at the second PRx location 1604 (represented by a second coordinate, such as X2, Y2). The Power Transmitter 102 can determine a shortest path 1606 to move the Power Transmitter 102 from its current location (such as the first coordinate (Xi, Yi) to a new target location 1610 (which can be same or near the second coordinate (X2, Y2).

[0099] FIG. 17 illustrates a block diagram of an example apparatus for use in a wireless power system. In some implementations, the apparatus 1700 may be a wireless power apparatus (such as any of the Power Transmitter or Power Receiver described herein. The apparatus 1700 can include a processor 1702 (possibly including multiple processors, multiple cores, multiple nodes, or implementing multi-threading, etc.). The apparatus 1700 also can include a memory 1704. The memory 1704 may be system memory or any one or more of the possible realizations of computer-readable media described herein. The apparatus 1700 also can include a bus 1706 (such as PCI, ISA, PCI-Express, HyperTransport®, InfiniBand®, NuBus®, AHB, AXI, etc.).

[0100] The apparatus 1700 may include one or more controllers 1708 (such as a PTx controller). In some implementations, the controller 1708 can be distributed within the processor 1702, the memory 1704, and the bus 1706. The controller 1708 may perform some or all of the operations described herein. For example, the controller 1708 may implement the processes described with reference to any one of FIG. 1A through FIG. 15, or any combination thereof.

[0101] The memory 1704 can include computer instructions executable by the processor 1702 to implement the functionality of the implementations described herein. Any one of these functionalities may be partially (or entirely) implemented in hardware or on the processor 1702. For example, the functionality may be implemented with an application specific integrated circuit, in logic implemented in the processor 1702, in a co-processor on a peripheral device or card, etc. Further, realizations may include fewer or additional components not illustrated in FIG. 17. The processor 1702, the memory 1704, and the controller 1708 may be coupled to the bus 1706. Although illustrated as being coupled to the bus 1706, the memory 1704 may be coupled to the processor 1702 or the controller 1708.

[0102] The apparatus 1700 also includes a protocol feature(s) 1710. The protocol feature(s) 1710 is controlled by the controller 1708. For example, the protocol feature(s) 1710 can be in a power supply (e.g., a power adapter) that is communicatively coupled to the controller 1708 of the Power Transmitter.

[0103] FIG. 1A through FIG. 17 and the operations described herein are examples meant to aid in understanding example implementations and should not be used to limit the potential implementations or limit the scope of the claims. Some implementations may perform additional operations, fewer operations, operations in parallel or in a different order, and some operations differently.

[0104] 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 may be acquired from practice of the aspects. While the aspects of the disclosure have been described in terms of various examples, any combination of aspects from any of the examples is also within the scope of the disclosure. The examples in this disclosure are provided for pedagogical purposes. Alternatively, or in addition to the other examples described herein, examples include any combination of the following implementation options (identified as clauses for reference).

[0105] Clause 1: A method of a Power Transmitter (PTx) for wireless power transfer, the method comprising: detecting a Power Receiver; and communicating, to the Power Receiver, a PTx type indication that indicates whether the Power Transmitter includes a movable primary coil.

[0106] Clause 2: The method of clause 1, wherein the PTx type indication further indicates that the Power Transmitter supports a magnetic power profile (MPP) mode.

[0107] Clause 3: The method of clause 2, wherein the PTx type indication further indicates that the Power Transmitter includes an electromagnetic ring for the MPP mode.

[0108] Clause 4: The method of any one of clauses 1 to 3, wherein communicating the PTx type indication includes communicating the PTx type indication via at least one of: an identification message; a capabilities message; or a configuration message.

[0109] Clause 5: The method of any one of clauses 1 to 4, wherein communicating the PTx type indication includes communicating the PTx type indication via a PTx communication according to a magnetic protocol for the MPP mode, wherein the PTx communication includes: an extended Power Transmitter identification (XID) packet; an extended Power Transmitter extended capabilities (ECAP) packet; or an extended Power Transmitter moving coil (MC) packet.

[0110] Clause 6: The method of clause 5, wherein communicating the PTx type indication includes: receiving, from the Power Receiver, a get request packet for requesting the PTx communication; and communicating the PTx communication in response to the get request packet.

[0111] Clause 7: The method of any one of clauses 1 to 3, wherein communicating the PTx type indication includes: receiving, from the Power Receiver, a specific request packet for requesting the PTx type indication; and communicating feedback to the Power Receiver in response to the specific request packet, wherein the feedback includes an acknowledgement (ACK) representing a first value of the PTx type indication or a non- acknowledgement (NAK) representing a second value of the PTx type indication.

[0112] Clause 8: The method of clause 7, further comprising: communicating the feedback as the ACK representing the first value of the PTx type indication when the Power Transmitter has the movable primary coil, or communicating the feedback as the NAK representing the second value of the PTx type indication when the Power Transmitter does not have the movable primary coil.

[0113] Clause 9: The method of any one of clauses 1 to 8, further comprising: determining that the Power Receiver supports a magnetic power profile (MPP) mode; and energizing anelectromagnetic ring of the Power Transmitter when the Power Transmitter activates the MPP mode based on the Power Receiver supporting the MPP mode.

[0114] Clause 10: The method of any one of clauses 1 to 8, further comprising: determining that the Power Receiver does not support a magnetic power profile (MPP) mode; and refraining from energizing the electromagnetic ring while the Power Transmitter is using a baseline power profile (BPP) mode or an extended power profile (EPP) mode for the Power Receiver that does not support the MPP mode.

[0115] Clause 11: The method of any one of clauses 1 to 10, wherein the Power Transmitter includes the movable primary coil, the method further comprising; negotiating, using a magnetic protocol for a magnetic power profile (MPP) mode, with the Power Receiver to determine settings for wireless power transfer; storing the settings in a memory of the Power Transmitter; performing the wireless power transfer in accordance with the settings; and after a communication disruption due to movement of the movable primary coil or the Power Receiver: retrieving the settings from the memory, reestablishing, using an abbreviated message exchange of the magnetic protocol, the settings for the wireless power transfer, and resuming the wireless power transfer in accordance with the settings.

[0116] Clause 12: The method of any one of clauses 1 to 11, further comprising: providing power to the Power Receiver; storing a first coordinate indicating an initial location of the Power Receiver or the Power Transmitter before a change in location of the Power Receiver; after the change in location of the Power Receiver: obtaining a second coordinate associated with a new location of the Power Receiver, and moving the movable primary coil of the Power Transmitter to a new target location for providing power to the Power Receiver based on a shortest path from the first coordinate to the second coordinate.

[0117] Clause 13: A method of a Power Receiver for wireless power transfer, the method comprising: communicating with a Power Transmitter (PTx); and receiving, from the Power Transmitter, a PTx type indication that indicates whether the Power Transmitter includes a movable primary coil.

[0118] Clause 14: The method of clause 13, wherein the PTx type indication further indicates at least one of: whether the Power Transmitter supports a magnetic power profile (MPP) mode; or whether the Power Transmitter includes an electromagnetic ring for the MPP mode.

[0119] Clause 15: The method of clause 13 or 14, wherein receiving the PTx type indication includes receiving the PTx type indication via at least one of: an identification message; a capabilities message; or a configuration message.

[0120] Clause 16: The method of any one of clauses 13 to 15, wherein receiving the PTx type indication includes receiving the PTx type indication via a PTx communication according to a magnetic protocol for the MPP mode, wherein the PTx communication includes: an extended Power Transmitter identification (XID) packet; an extended Power Transmitter extended capabilities (ECAP) packet; or an extended Power Transmitter moving coil capability (MCC) packet.

[0121] Clause 17: The method of clause 16, wherein receiving the PTx type indication includes: communicating, to the Power Transmitter, a get request packet for requesting the PTx communication; and receiving the PTx communication in response to the get request packet.

[0122] Clause 18: The method of any one of clauses 13 to 15, wherein receiving the PTx type indication includes: communicating, to the Power Transmitter, a specific request packet for requesting the PTx type indication; and receiving feedback from the Power Receiver in response to the specific request packet, wherein the feedback includes an acknowledgement (ACK) representing a first value or a non-acknowledgement (NAK) representing a second value, wherein: the first value indicates the Power Transmitter has the movable primary coil, and the second value indicates the Power Transmitter does not have the movable primary coil.

[0123] Clause 19: The method of any one of clauses 13 to 18, further comprising: activating a magnetic power profile (MPP) mode based, at least in part, on the PTx type indication when the PTx type indication indicates that the Power Transmitter includes the movable primary coil and supports a magnetic power profile (MPP) mode using an electromagnetic ring.

[0124] Clause 20: The method of any one of clauses 13 to 19, further comprising: negotiating, using a magnetic protocol for a magnetic power profile (MPP) mode, settings for wireless power transfer; storing the settings in a memory of the Power Receiver; performing the wireless power transfer in accordance with the settings; and after a communication disruption due to movement of the movable primary coil or the Power Receiver: retrieving the settings from the memory, reestablishing, using an abbreviated message exchange of the magnetic protocol, the settings for the wireless power transfer, and resuming the wireless power transfer in accordance with the settings.

[0125] Clause 21: A Power Transmitter (PTx) for wireless power transfer, comprising: a movable primary coil capable of transmitting wireless power to a Power Receiver; and a communication unit configured to communicate, to the Power Receiver, a PTx type indication that indicates that the Power Transmitter includes the movable primary coil.

[0126] Clause 22: The Power Transmitter of clause 21, wherein the PTx type indication further indicates at least one of: whether the Power Transmitter supports a magnetic power profile (MPP) mode; or whether the Power Transmitter includes an electromagnetic ring for the MPP mode.

[0127] Clause 23: The Power Transmitter of clause 21 or 22, further comprising: an electromagnetic ring; and a controller designed to: cause the Power Transmitter to energize the electromagnetic ring when the Power Transmitter activates the MPP mode for the Power Receiver.

[0128] Clause 24: The Power Transmitter of clause 23, wherein the controller is further designed to: cause the Power Transmitter to refrain from energizing the electromagnetic ring while the Power Transmitter is using a baseline power profile (BPP) mode or an extended power profile (EPP) mode for the Power Receiver.

[0129] Clause 25: The Power Transmitter of clause 23 or 24, wherein the electromagnetic ring includes: a plurality of electromagnets arranged in a single layer of a ring or arc shape; and a wire joining the plurality of electromagnets in a series, the wire wound around a center ferrite portion of each of the plurality of electromagnets such that each electromagnet generates an alternating pole magnetic property when current is applied to the wire.

[0130] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this specification belongs. The terms “first,” “second,” and the like, as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The use of terms “including,” “comprising” or “having” and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “connected” and “coupled” are not restricted to physical or mechanical connections or couplings and can include electrical connections or couplings, whether direct or indirect. Furthermore, terms “circuit” and “circuitry” and “control unit” may include either a single component or a plurality of components, which are either active and / or passive and are connected or otherwise coupled together to provide the described function. In addition, the term operationally coupled as used herein includes wired coupling, wireless coupling, electrical coupling, magnetic coupling, radio communication, software based communication, or combinations thereof.

[0131] Some or all of the foregoing or the following implementations can be jointly combined or formed to be a new or another one implementation. The foregoing or the following techniques can be used to solve at least (but not limited to) the issue(s) orscenario(s) mentioned in this disclosure. Any two or more than two of the foregoing or the following paragraphs, (sub)-bullets, points, actions, or claims described in each method / technique / implementation may be combined logically, reasonably, and properly to form a specific method. Any sentence, paragraph, (sub)-bullet, point, action, or claim described in each of the foregoing or the following technique(s) / implementation(s) / concept(s) may be implemented independently and separately to form a specific method. Dependency, such as “based on,” “more specifically,” “where” or etc., in technique(s) / implementation(s) / concept(s) mentioned in this disclosure is just one possible implementation which would not restrict the specific method.

[0132] Certain techniques are described in this disclosure as including logic or a number of components or modules. Modules can be software modules (e.g., code, or machine-readable instructions stored on non-transitory machine-readable medium) or hardware modules. A hardware module is a tangible unit capable of performing certain operations and may be configured or arranged in a certain manner. A hardware module can comprise dedicated circuitry or logic that is permanently configured (e.g., as a special-purpose processor, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), a digital signal processor (DSP), etc.) to perform certain operations. A hardware module may also comprise programmable logic or circuitry (e.g. , as encompassed within a general-purpose processor or other programmable processor) that is temporarily configured by software to perform certain operations. The decision to implement a hardware module in dedicated and permanently configured circuitry, or in temporarily configured circuitry (e.g., configured by software) may be driven by cost and time considerations.

[0133] When implemented in software, the techniques can be provided as part of the operating system, a library used by multiple applications, a particular software application, etc. The software can be executed by one or more general-purpose processors or one or more special-purpose processors.

[0134] As used herein, the terms “component” and “module” are intended to be broadly construed as hardware, firmware, or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, or a combination of hardware and software. As used herein, the phrase “based on” is intended to be broadly construed to mean “based at least in part on.”

[0135] As used herein, a phrase referring to a list of items separated by “or” refers to any combination of those items, including single members. For example, “a, b, or c” is intendedto cover the possibilities of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c.

[0136] In this disclosure, an expression of “X / Y” may include meaning of any of the following: “X or Y” or “X and Y” or “X and / or Y." An expression of “(A) B” or “B (A)” may include concept of “only B.” An expression of “(A) B” or “B (A)” may include the concept of “A+B” or “B+A.”

[0137] Some aspects are described herein in connection with thresholds. As used herein, satisfying a threshold may refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, or the like.

[0138] The various illustrative components, logic, logical blocks, modules, circuits, operations and algorithm 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 in this specification and the structural equivalents thereof. The interchangeability of hardware, firmware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware, firmware or software depends upon the particular application and design constraints imposed on the overall system.

[0139] As described above, some aspects of the subject matter described in this specification can be implemented as software. For example, various functions of 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 can 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 to control the operation of, a data processing apparatus including the components of the devices described herein. By way of example, and not limitation, such storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store program code in the form of instructions or data structures. Combinations of the above should also be included within the scope of storage media.

[0140] Various modifications to the implementations described in this disclosure may be readily apparent to persons having ordinary skill in the art, and the generic principles definedherein may be applied to other implementations without departing from the scope of this 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 this disclosure, the principles and the novel features disclosed herein.

[0141] Additionally, various features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. As such, although features may be described above as acting in particular combinations, and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0142] The drawings may schematically depict one or more example processes in the form of a flowchart or flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In some circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

Claims

CLAIMSWhat is claimed is:

1. A method of a Power Transmitter (PTx) for wireless power transfer, the method comprising: detecting a Power Receiver; and communicating, to the Power Receiver, a PTx type indication that indicates whether the Power Transmitter includes a movable primary coil.

2. The method of claim 1, wherein the PTx type indication further indicates that the Power Transmitter supports a magnetic power profile (MPP) mode.

3. The method of claim 1 or 2, wherein communicating the PTx type indication includes communicating the PTx type indication via at least one of: an identification message; a capabilities message; or a configuration message.

4. The method of any one of claims 1 to 3, wherein communicating the PTx type indication includes communicating the PTx type indication via a PTx communication according to a magnetic protocol for the MPP mode, wherein the PTx communication includes: an extended Power Transmitter identification (XID) packet; an extended Power Transmitter extended capabilities (ECAP) packet; or an extended Power Transmitter moving coil (MC) packet.

5. The method of any one of claims 1 to 4, wherein communicating the PTx type indication includes: receiving, from the Power Receiver, a get request packet for requesting the PTx communication; and communicating the PTx type indication via a communication in response to the get request packet.

6. The method of any one of claims 1 to 4, wherein communicating the PTx type indication includes: receiving, from the Power Receiver, a specific request packet for requesting the PTx type indication; andcommunicating feedback to the Power Receiver in response to the specific request packet, wherein the feedback includes an acknowledgement (ACK) representing a first value of the PTx type indication or a non-acknowledgement (NAK) representing a second value of the PTx type indication.

7. The method of claim 6, further comprising: communicating the feedback as the ACK representing the first value of the PTx type indication when the Power Transmitter has the movable primary coil, or communicating the feedback as the NAK representing the second value of the PTx type indication when the Power Transmitter does not have the movable primary coil.

8. The method of any one of claims 1 to 7, further comprising: determining that the Power Receiver supports a magnetic power profile (MPP) mode with the movable primary coil; and activating the MPP mode when the Power Transmitter activates the MPP mode based on the Power Receiver supporting the MPP mode with the movable primary coil.

9. The method of any one of claims 1 to 7, wherein the Power Transmitter includes the movable primary coil, the method further comprising; negotiating, using a magnetic protocol for a magnetic power profile (MPP) mode, with the Power Receiver to determine settings for wireless power transfer; storing the settings in a memory of the Power Transmitter; performing the wireless power transfer in accordance with the settings; and after a communication disruption due to movement of the movable primary coil or the Power Receiver: retrieving the settings from the memory, reestablishing, using an abbreviated message exchange of the magnetic protocol, the settings for the wireless power transfer, and resuming the wireless power transfer in accordance with the settings.

10. The method of any one of claims 1 to 9, further comprising: providing power to the Power Receiver; storing a first coordinate indicating an initial location of the Power Receiver or the Power Transmitter before a change in location of the Power Receiver; after the change in location of the Power Receiver: obtaining a second coordinate associated with a new location of the PowerReceiver, andmoving the movable primary coil of the Power Transmitter to a new target location for providing power to the Power Receiver based on a shortest path from the first coordinate to the second coordinate.

11. A method of a Power Receiver for wireless power transfer, the method comprising: communicating with a Power Transmitter (PTx); and receiving, from the Power Transmitter, a PTx type indication that indicates whether the Power Transmitter includes a movable primary coil.

12. The method of claim 11 , wherein receiving the PTx type indication includes receiving the PTx type indication via at least one of: an identification message; a capabilities message; or a configuration message.

13. The method of claim 11 or 12, wherein receiving the PTx type indication includes receiving the PTx type indication via a PTx communication according to a magnetic protocol for the MPP mode, wherein the PTx communication includes: an extended Power Transmitter identification (XID) packet; an extended Power Transmitter extended capabilities (ECAP) packet; or an extended Power Transmitter moving coil capability (MCC) packet.

14. The method of claim 13, wherein receiving the PTx type indication includes: communicating, to the Power Transmitter, a get request packet for requesting the PTx communication; and receiving the PTx communication in response to the get request packet.

15. The method of claim 11 or 12, wherein receiving the PTx type indication includes: communicating, to the Power Transmitter, a specific request packet for requesting thePTx type indication; and receiving feedback from the Power Receiver in response to the specific request packet, wherein the feedback includes an acknowledgement (ACK) representing a first value or a non-acknowledgement (NAK) representing a second value, wherein: the first value indicates the Power Transmitter has the movable primary coil, and the second value indicates the Power Transmitter does not have the movable primary coil.

16. The method of any one of claims 11 to 15, further comprising: activating a magnetic power profile (MPP) mode based, at least in part, on the PTx type indication when the PTx type indication indicates that the Power Transmitter includes the movable primary coil and supports the magnetic power profile (MPP) mode.

17. The method of any one of claims 11 to 16, further comprising: negotiating, using a magnetic protocol for a magnetic power profile (MPP) mode, settings for wireless power transfer; storing the settings in a memory of the Power Receiver; performing the wireless power transfer in accordance with the settings; and after a communication disruption due to movement of the movable primary coil or the Power Receiver: retrieving the settings from the memory, reestablishing, using an abbreviated message exchange of the magnetic protocol, the settings for the wireless power transfer, and resuming the wireless power transfer in accordance with the settings.

18. A Power Transmitter (PTx) for wireless power transfer, comprising: a movable primary coil capable of transmitting wireless power to a Power Receiver; and a communication unit configured to communicate, to the Power Receiver, a PTx type indication that indicates that the Power Transmitter includes the movable primary coil.

19. The Power Transmitter of claim 18, wherein the PTx type indication further indicates whether the Power Transmitter supports a magnetic power profile (MPP) mode.

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