Detecting coil misalignment in a wireless charging system

Abstract

A wireless charging system can include a wireless power receiving device that receives a wireless power signal from a wireless power transmitting device. The wireless power transmitting device can include positioning equipment that moves a wireless power transmission coil to align the wireless power transmission coil for wireless power transmission. The wireless power transmitting device can periodically evaluate coil alignment during a wireless power transmission session by intermittently checking efficiency or an inductive coupling factor.

Description

[0001] This application claims priority to U.S. Patent Application No. 18 / 781,299, filed July 23, 2024, and U.S. Provisional Patent Application No. 63 / 632,781, filed April 11, 2024, each of which is incorporated herein by reference in its entirety. Technical Field

[0002] This disclosure relates in general to power systems, and more specifically to wireless power systems for charging electronic devices. Background Technology

[0003] In a wireless charging system, a wireless power transmitting device with a wireless power transmission coil sends wireless power to a wireless power receiving device with a wireless power transmission coil. The wireless power receiving device uses the wireless power to charge the battery and / or power components. If the wireless power transmission coil is misaligned, the efficiency of wireless power transmission may be lower than expected. Summary of the Invention

[0004] An electronic device may be configured to transmit wireless power with an attached electronic device. The electronic device may include: a wireless power transmission coil; an inverter configured to supply an AC drive signal to the wireless power transmission coil; a positioning device configured to move the wireless power transmission coil; and control circuitry configured to: after the commencement of a wireless power transmission session, cause a first pause in the wireless power transmission session for a first duration; during the first pause, determine an inductive coupling factor between the electronic device and the attached electronic device; based on the inductive coupling factor, cause a second pause in the wireless power transmission session for a second duration, the second duration being greater than the first duration; and during the second pause, use the positioning device to move the wireless power transmission coil.

[0005] An electronic device may be configured to transmit wireless power with an attached electronic device. The electronic device may include: a wireless power transmission coil; an inverter configured to supply an AC drive signal to the wireless power transmission coil; a positioning device configured to move the wireless power transmission coil; and control circuitry configured to: during a wireless power transmission session, identify that the attached electronic device has reduced a rectifier output load to a non-zero value; when the rectifier output load in the attached electronic device has the non-zero value, determine an inductive coupling factor between the electronic device and the attached electronic device; and based on the inductive coupling factor, use the positioning device to move the wireless power transmission coil.

[0006] An electronic device may be configured to transmit wireless power with an attached electronic device. The electronic device may include: a wireless power transmission coil; an inverter configured to supply an AC drive signal to the wireless power transmission coil; a positioning device configured to move the wireless power transmission coil; and control circuitry configured to: collect baseline efficiency information during the transmission of wireless power with the attached electronic device during a calibration phase of a wireless power transmission session; receive efficiency information from the attached electronic device during the transmission of wireless power with the attached electronic device during the wireless power transmission session; and use the positioning device to move the wireless power transmission coil based on the baseline efficiency information and the efficiency information from the attached electronic device. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of an exemplary wireless power system based on some implementation schemes.

[0008] Figure 2 It is a circuit diagram of a wireless power transmission and reception circuit according to some implementation schemes.

[0009] Figure 3 This is a side view of an exemplary wireless power transmitting device, such as a wireless charging pad, connected via a cable to a connector plug according to some implementation schemes.

[0010] Figure 4 This is an illustration of an exemplary wireless power system based on some implementation schemes, showing different power levels at different locations within the system.

[0011] Figure 5A This is a side view of an exemplary wireless power system with positioning equipment according to some implementation schemes before the coil alignment process.

[0012] Figure 5B It is based on some implementation plans. Figure 5A A side view of an exemplary wireless power system after the coil alignment process.

[0013] Figure 6 This is a top view of an exemplary wireless power transmitting device with a coil that can be repositioned below the charging surface, according to some implementation schemes.

[0014] Figure 7 This is a timeline of exemplary operation of a wireless power transmission device with coil alignment, based on some implementation schemes, to check the efficiency of wireless power transmission.

[0015] Figure 8 This is a flowchart illustrating an exemplary method for checking the efficiency of wireless power transmission to evaluate a coil-aligned wireless power transmitting device according to some implementation schemes.

[0016] Figure 9 It is a timeline of exemplary operation of a coil-aligned wireless power transmission device, based on estimates of the inductive coupling factor of some implementation schemes.

[0017] Figure 10 This is a flowchart illustrating an exemplary method for estimating the inductive coupling factor to evaluate a coil-aligned wireless power transmitting device based on the operation of some implementation schemes. Detailed Implementation

[0018] Figure 1 An exemplary wireless power system (sometimes also called a wireless charging system) is shown. For example... Figure 1 As shown, the wireless power system 8 may include one or more wireless power transmitting devices such as wireless power transmitting device 12, and one or more wireless power receiving devices such as wireless power receiving device 24. The wireless power system 8 may also be referred to herein as a wireless power transmission (WPT) system 8 or simply wireless power system 8. The wireless power transmitting device 12 may also be referred to herein as a power transmitter (PTX) device 12 or simply PTX 12. The wireless power receiving device 24 may also be referred to herein as a power receiver (PRX) device 24 or simply PRX 24.

[0019] PTX device 12 includes control circuitry 16. Control circuitry 16 is mounted within housing 30. PRX device 24 includes control circuitry 38 mounted within a corresponding housing 52 of PRX device 24. Exemplary control circuitry 16 and control circuitry 38 are used to control the operation of WPT system 8. This control circuitry may include processing circuitry, which includes one or more processors, such as a microprocessor, power management unit, baseband processor, digital signal processor, microcontroller, graphics processing unit (GPU), central processing unit (CPU), application processor (AP), application-specific integrated circuit (ASIC) with processing circuitry, and / or other processing circuitry. The processing circuitry implements desired control and communication features in PTX device 12 and PRX device 24. For example, the processing circuitry may be used to control power supply to one or more coils, determine and / or set power transmission levels, generate and / or process sensor data (e.g., to detect foreign objects and / or external electromagnetic signals or fields), process user input, handle negotiation between PTX device 12 and PRX device 24, transmit and receive in-band and out-of-band data, perform measurements, and / or otherwise control the operation of WPT system 8.

[0020] The control circuitry (e.g., control circuitry 16 and / or 38) in WPT system 8 is configured to perform operations within WPT system 8 using hardware (e.g., dedicated hardware or circuitry), firmware, and / or software. Software code used to perform operations within WPT system 8 is stored on a non-transitory computer-readable storage medium (e.g., a tangible computer-readable storage medium) within the control circuitry of WPT system 8. Software code may sometimes be referred to as software, data, program instructions, commands, or code. The non-transitory computer-readable storage medium may include non-volatile memory such as non-volatile random access memory (NVRAM), one or more hard disk drives (e.g., disk drives or solid-state drives), one or more removable flash drives, or other removable media. The software stored on the non-transitory computer-readable storage medium can be executed on the processing circuitry of control circuitry 16 and / or 38.

[0021] PTX device 12 can be a standalone power adapter (e.g., a wireless charging pad or charging dock including power adapter circuitry), a wireless charging pad or charging dock connected via cable to a power adapter or other equipment, an electronic device (e.g., a laptop computer, desktop computer, computer monitor containing an embedded computer, tablet computer, cellular phone, media player, or other handheld or portable electronic device; smaller devices such as wristwatches, hanging devices, headphones or handsets, devices embedded in glasses, goggles, or other equipment worn on a user's head, or other wearable or micro-devices; televisions, computer monitors without embedded computers, gaming devices, navigation devices, voice-controlled speakers connected to the wireless internet, home entertainment devices, remote control devices, game controllers, peripheral user input devices, wireless base stations or access points, equipment enabling the functionality of two or more of these devices; or other electronic equipment), equipment already integrated into furniture, vehicles, or other systems, a removable battery box, or other wireless power transmission equipment.

[0022] PRX device 24 can be: electronic devices such as laptop computers, desktop computers, computer monitors containing embedded computers, tablet computers, cellular phones, media players, or other handheld or portable electronic devices; smaller devices such as wristwatches, wristbands, headphones, or handsets, devices embedded in glasses, goggles, or other equipment worn on a user's head, or other wearable or micro-devices; wireless tracking tags; televisions, computer monitors without embedded computers, gaming devices, navigation devices, voice-controlled speakers connected to the wireless internet, home entertainment devices, remote control devices, game controllers, peripheral user input devices, wireless base stations or access points, equipment that enables the functionality of two or more of these devices; or other electronic equipment.

[0023] PTX device 12 may be connected to a wall socket (e.g., an AC power source), may be coupled to the wall socket via an external power adapter, may have a battery for supplying power, and / or may have another power source. In a specific embodiment where PTX device 12 is coupled to the wall socket via an external power adapter, the adapter may have an AC-to-DC power converter that converts AC power from the wall socket or other power source into DC power. If desired, PTX device 12 may include a DC-DC power converter for converting DC power between different DC voltages. Additionally or alternatively, PTX device 12 may include an AC-to-DC power converter that generates DC power from AC power supplied from the wall socket (e.g., in a specific embodiment where PTX device 12 is connected to the wall socket without an external power adapter). The DC power can be used to power control circuitry 16. During operation, the controller in control circuitry 16 uses power transmission circuitry 22 to transmit wireless power to power receiving circuitry 46 of PTX device 24.

[0024] The power transmitting circuit 22 may have switching circuitry, such as an inverter circuit 26 formed of transistors, which are turned on or off based on control signals provided by the control circuit 16, thereby creating AC current signals through one or more wireless power transmitting coils (such as wireless power transmitting coil 32). These coil drive signals cause coil 32 to transmit wireless power. In embodiments where coil 32 includes multiple coils, the coils may be mounted on a ferromagnetic structure, arranged in a planar coil array, or arranged to form a coil cluster (e.g., two or more coils, 5 to 10 coils, at least 10 coils, 10 to 30 coils, fewer than 35 coils, fewer than 25 coils, or other suitable number of coils). In some embodiments, the PTX device 12 includes only a single coil 32.

[0025] When an AC current passes through one or more coils 32, an alternating electromagnetic (e.g., magnetic) field (wireless power signal 44) is generated. This alternating electromagnetic field is received by one or more corresponding receiver coils (such as coil 48 in PRX device 24). In other words, one or more coils in coil 32 are inductively coupled to one or more coils in coil 48. PRX device 24 may have a single coil 48, at least two coils 48, at least three coils 48, at least four coils 48, or other suitable number of coils 48. When the alternating electromagnetic field is received by coil 48, a corresponding alternating current is induced in coil 48. The AC signal used to transmit wireless power may have any desired frequency (e.g., 100kHz to 400kHz, 1MHz to 100MHz, between 1.7MHz and 1.8MHz, below 2MHz, between 100kHz and 2MHz, etc.). A rectifier circuit, such as rectifier circuit 50 (which includes rectifier components, such as synchronous rectifier transistors arranged in a bridge network), converts an AC signal (a received AC signal associated with wireless power signal 44) received from one or more coils 48 into a DC voltage signal for powering the PRX device 24. Wireless power signal 44 is sometimes referred to herein as wireless power 44 or wireless charging signal 44. Coil 32 is sometimes referred to herein as wireless power transmission coil 32, wireless charging coil 32, or wireless power transmitting coil 32. Coil 48 is sometimes referred to herein as wireless power transmission coil 48, wireless charging coil 48, or wireless power receiving coil 48.

[0026] The DC voltage generated by rectifier circuit 50 (sometimes referred to as rectifier output voltage V) RECT_DC This can be used to charge a battery (such as battery 34) and to power other components in the PTX device 24 (such as control circuitry 38, input / output (I / O) devices 54, etc.). The PTX device 12 may also include input / output devices, such as input / output device 28. Input / output device 54 and / or input / output device 28 may include input devices for collecting user input and / or performing environmental measurements, and may include output devices for providing output to the user.

[0027] For example, input-output device 28 and / or input-output device 54 may include a display (screen) for creating visual output, a speaker for presenting the output as an audio signal, light-emitting diode status indicators, and other light-emitting components for emitting light to provide status information and / or other information to the user, tactile devices for generating vibrations and other tactile outputs, and / or other output devices. Input-output device 28 and / or input-output device 54 may also include sensors for collecting input from the user and / or for measuring the surrounding environment of WPT system 8.

[0028] The input-output device 28 may include one or more sensors 202 that detect the position of one or more coils 48 in the PRX 24 when the PRX 24 is placed on the PTX 12 for wireless power transmission. The one or more sensors 202 may include one or more sensor coils, one or more magnetic sensors, one or more temperature sensors, etc.

[0029] Alignment of coil 32 with coil 48 may be desired to improve efficiency during wireless power transfer. PTX 12 may include a positioning device 204 configured to move coil 32 based on the position of coil 48 detected by sensor 202. In this way, coil 32 can be aligned with coil 48 regardless of where PRX 24 is placed on PTX 12. During a wireless power transfer session, PRX 24 or PTX 12 may move relative to another device, causing coil 48 to become misaligned with coil 32. When misalignment between coil 32 and coil 48 is detected, sensor 202 can detect the new position of coil 48, and positioning device 204 can move coil 32 to become aligned with the new position of coil 48.

[0030] The positioning device 204 may include one or more stepper motors, piezoelectric actuators, motors, linear electromagnetic actuators, shape memory alloys (SMA), and / or other electronic components for adjusting the position of the coil 32.

[0031] Figure 1 The example of the PRX device 24 including battery 34 is illustrative. More generally, electronic devices may include power storage device 34. Power storage device 34 may be a battery, or it may be, for example, a supercapacitor that stores electrical charge.

[0032] PTX device 12 and PRX device 24 can communicate wirelessly using in-band or out-of-band communication. Specific implementations of in-band communication can utilize, for example, Frequency Shift Keying (FSK) and / or Amplitude Shift Keying (ASK) technologies to transmit in-band data between PTX device 12 and PRX device 24. Coils 32 and 48 can be used simultaneously to transmit wireless power and in-band data. When PTX 12 transmits in-band data to PRX 24, wireless transceiver (TX / RX) circuitry 20 can modulate wireless charging signal 44 to apply FSK or ASK communication, and wireless transceiver circuitry 40 can demodulate wireless charging signal 44 to obtain the data being transmitted. When PRX 24 transmits in-band data to PTX 12, wireless transceiver (TX / RX) circuitry 40 can modulate wireless charging signal 44 to apply FSK or ASK communication, and wireless transceiver circuitry 20 can demodulate wireless charging signal 44 to obtain the data being transmitted.

[0033] Specific implementations of out-of-band communication may utilize, for example, hardware antenna structures and communication protocols such as Bluetooth or NFC to transmit out-of-band data between PTX device 12 and PRX device 24. Power may be wirelessly transmitted between coil 32 and coil 48 simultaneously with out-of-band data transmission. Wireless transceiver circuit 20 may use an antenna (such as antenna 56) to wirelessly transmit and / or receive out-of-band signals to and / or from PRX device 24. Wireless transceiver circuit 40 may use an antenna (such as antenna 58) to wirelessly transmit and / or receive out-of-band signals to and / or from PTX device 12.

[0034] The control circuit 16 in the PTX device 12 includes a measurement circuit 18, which can be used to perform measurements on one or more characteristics of the exterior of the PTX device 12. For example, the measurement circuit 18 can detect external objects on or near the charging surface of the housing of the PTX device 12. Although for clarity... Figure 1 The measurement circuit 18 is shown as separate from the power transmission circuit 22, but if desired, the measurement circuit 18 may be part of the power transmission circuit 22.

[0035] Measurement circuit 18 can detect foreign objects (such as coils, paper clips, and other metallic objects), the presence of PRX device 24 (e.g., circuit 18 can detect the presence of one or more coils 48 and / or the magnetic core material associated with coil 48), and / or the presence of other power transmitting devices near PTX device 12 and / or WPT system 8. Measurement circuit 18 can also be used to perform sensor measurements using capacitive sensors, to perform temperature measurements, and / or otherwise collect information indicating the presence of foreign objects, power transmitting devices, power receiving devices, or other external objects (e.g., PRX device 24) on or near coil 32 of PTX device 12. If desired, PRX device 24 may include measurement circuit 42. Measurement circuit 42 can perform one or more measurements performed by measurement circuit 18 (e.g., for or using coil 48 on PRX device 24).

[0036] Each of housing 30 and housing 52 may be formed of plastic, metal, fiber composite material (such as carbon fiber material), wood and other natural materials, glass, other materials and / or a combination of two or more of these materials.

[0037] The PTX 12 transmits wireless power and the PRX 24 receives wireless power. Figure 1 The examples in the diagram are merely illustrative. PTX 12 may optionally be able to receive wireless power signals using coil 32 and PTX 24 may optionally be able to transmit wireless power signals using coil 48. When a device is capable of both transmitting and receiving wireless power signals, it may include both an inverter and a rectifier.

[0038] Figure 2 This is a circuit diagram of an exemplary wireless charging circuit for System 8. (For example...) Figure 2 As shown, circuit 22 may include inverter circuitry such as one or more inverters 26 or other drive circuitry that generates a wireless power signal, which is transmitted via an output circuit including one or more coils 32 and a capacitor such as capacitor 70. In some embodiments, device 12 may include multiple individually controlled inverters 26, each of which provides a drive signal to a corresponding coil 32. In other embodiments, a switching circuit is used to share an inverter 26 among multiple coils 32.

[0039] During operation, control signals for inverter 26 are provided by control circuit 16 at one or more control inputs 74. Figure 2 The example shows a single inverter 26 and a single coil 32, but multiple inverters 26 and multiple coils 32 can be used if desired. In a multi-coil configuration, switching circuitry (e.g., multiplexer circuitry) can be used to couple a single inverter 26 to multiple coils 32 and / or each coil 32 can be coupled to a corresponding inverter 26. During wireless power transmission operation, transistors in one or more selected inverters 26 are driven by AC control signals from control circuitry 16. The relative phase between the inverters can be dynamically adjusted (e.g., a pair of inverters 26 can produce in-phase or out-of-phase output signals).

[0040] An inverter 26 (e.g., a transistor or other switch in circuit 22) is used to apply a drive signal to cause an output circuit formed by a selected coil 32 and a capacitor 70 to generate an AC electromagnetic field (signal 44), which is received by a wireless power receiving circuit 46 using a wireless power receiving circuit formed by one or more coils 48 and one or more capacitors 72 in device 24.

[0041] The rectifier circuit 50 is coupled to one or more coils 48 and converts the received power from AC to DC, providing a corresponding DC output voltage V at the rectifier output terminal 76. RECT_DC For use in powering load circuitry in device 24 (e.g., for charging battery 34, for powering display and / or other input-output devices 54, and / or for powering other components).

[0042] Figure 2The diagram illustrates how measurement circuitry 18 within PTX 12 may include one or more voltage sensors (such as voltage sensor 18A) and one or more current sensors (such as current sensor 18B). Additionally, measurement circuitry 42 within PTX 24 may include one or more voltage sensors (such as voltage sensor 42A) and one or more current sensors (such as current sensor 42B). The voltage and current sensors within system 8 can be used to determine the power level within the system.

[0043] Figure 2 The specific locations of sensors 18A, 18B, 42A, and 42B (located on the DC side of inverter 26 and rectifier 50, respectively) are merely illustrative. In general, voltage and current sensors can be located at any desired location within power transmitting circuit 22 and power receiving circuit 46 (e.g., on the AC side of inverter 26 and rectifier 50, if desired).

[0044] Figure 3 This is a cross-sectional side view of system 8 in an exemplary configuration, where the wireless power transmitting device 12 is a wireless charging dock, and the wireless power receiving device 24 is a wristwatch (as an example). Figure 3 As shown, device 12 has a device housing 30 (e.g., a disc-shaped charging dock housing formed of polymer, other dielectric materials, and / or other materials). The device housing 30 may accommodate a device microcontroller for communication with plug 94, DC-DC power converter circuitry (such as a buck voltage converter, e.g., a step-down converter), voltage regulator circuitry (such as a low-dropout (LDO) regulator), and wireless power transmission circuitry (such as an inverter 26, see [link]). Figure 2 ), coil 32, capacitor 70, near field communication (NFC) circuit for communicating with power receiving device 24, over-temperature protection (OTP) circuit (such as a temperature sensor), debugging circuit, filter circuit, sensor 202 for positioning coil 48 in PRX 24, positioning device 204 for moving coil 32, magnetic alignment structure (such as a magnet for attracting device 24 during charging operation) and / or other power transmitting device components.

[0045] Cable 92 is coupled to device housing 30 and provides power to coil 32. One end of cable 92 may be connected to housing 30 as a lead. The opposite end of cable 92 is terminated with plug 94. Plug 94 has a protective cover portion 98, sometimes referred to as a "protective shield" of the plug. Cable 92 and plug 94 may be considered as part of PTX 12 or as separate components from PTX 12. Protective cover 98 (sometimes referred to as connector protective cover) may be formed of polymer, metal and / or other materials and may have an internal area configured to accommodate electronic components (e.g., integrated circuits, discrete components such as transistors, printed circuits, etc.). Protective cover 98 has a first end connected to cable 92 and a second end connected to connector portion 96 (sometimes referred to as a "connector" of the plug). Connector 96 may include pins configured to mate with corresponding pins in port 102 of external equipment (such as device 100). Device 100 may be a stand-alone power adapter that converts alternating current (AC) power to direct current (DC) power, electronic equipment such as a computer, or other equipment that provides DC power to plug 94 via port 102. Port 102 may be, for example, a USB port (e.g., a USB Type-C port, a USB 4.0 port, a USB 3.0 port, a USB 2.0 port, a micro USB port, etc.) or a Lightning connector port. Plug 96 having a connector protruding from protective cover 98 may be referred to as a male plug. Plug 96 may be a reversible plug (i.e., a plug that mates with corresponding connector ports in at least two different and symmetrical orientations).

[0046] During wireless power transfer operation, it may be desirable to measure the efficiency of wireless power transfer between the PTX 12 and PRX 24. Figure 4 The power transfer via system 8 is illustrated. Power adapter 100 (such as...) Figure 3 The power adapter can receive power from a power source such as the wall socket 110. The wall socket 110 can provide power at a first power level P. MAINS The power adapter 100 converts the received AC power into DC power. The DC power output from the power adapter may have a second power level P. ADPT The plug, including the protective housing portion 98, can be coupled to the power adapter 100. The protective housing portion 98 may include an output having a third level P. BOOT The power conversion circuit provides DC power. The power output from the protective enclosure section 98 can be (e.g., using cable 92 and / or other circuitry within the power transmitting device 12) supplied to the inverter 26 within the housing 30. The inverter 26 uses the input power P BOOT This generates an AC current signal via the wireless power transmission coil 32. The AC signal generated by the inverter 26 and provided to the transmission (TX) coil 32 can have a fourth power level P.INV .

[0047] When AC current passes through one or more coils 32, it generates an alternating electromagnetic (e.g., magnetic) field (wireless power signal 44), which is received by one or more corresponding receiver coils (such as coil 48 in PRX device 24). The signal received at RX coil 48 may have a fifth power level P. RECT_AC Rectifier 50 will convert the AC power received at RX coil 48 into sixth-level P. RECT_DC DC power.

[0048] There may be power inefficiencies associated with each stage of power transfer through system 8. In other words, power adapter 100 has characteristics that lead to P... ADPT Less than P MAINS The associated power conversion and / or consumption inefficiency, the protective cover section 98 has a leading effect on P BOOT Less than P ADPT The associated power inefficiency of inverter 26 leads to P INV Less than P BOOT The associated power inefficiency, the wireless power transfer between TX coil 32 and RX coil 48 has the effect of causing P RECT_AC Less than P INV The associated power inefficiency, and the rectifier 50 has the characteristic that leads to P RECT_DC Less than P RECT_AC The associated power inefficiency (e.g., P) MAINS >P ADPT >P BOOT >P INV >P RECT_AC >P RECT_DC ).

[0049] Given the varying power levels within a wireless power system, there are many ways to characterize the efficiency within the system. Generally, efficiency can be defined as the ratio of two power levels within the system, where the numerator power level is downstream (and therefore lower) from the denominator power level in power transmission.

[0050] The efficiency of wireless power transfer between PTX 12 and PRX 24 can be characterized by the ratio of at least one power level in PRX 24 to at least one power level in PTX 12 or power adapter 100. For example, the efficiency of wireless power transfer between PTX 12 and PRX 24 can be characterized by P RECT_DC With P INV The ratio (e.g., E) TRANSFER =P RECT_DC / P INV ).

[0051] The operating efficiency of the PTX 12 can be characterized by the ratio of two power levels within the PTX 12 or power adapter 100. For example, the operating efficiency of the PTX 12 can be characterized as P... INV and P ADPT The ratio (e.g., E) PTX =P INV / P ADPT ) or characterized as P INV and P BOOT The ratio (e.g., E) PTX =P INV / P BOOT ).

[0052] During wireless power transfer operations, PRX 24 may report efficiency information to PTX 12, and / or PTX 12 may report efficiency information to PRX 24. Efficiency information may include efficiency information associated with wireless power transfer (e.g., E...). TRANSFER =P RECT_DC / P INV In some cases, efficiency can be determined by PRX 24 and reported directly to PTX 12. In other cases, PRX 24 can send information that PTX 12 subsequently uses to derive efficiency (e.g., power level information, current information, and / or voltage information).

[0053] As an example, the PRX 24 can (e.g., using current and / or voltage measurements) determine P RECT_DC PRX 24 can report P to PTX 12 RECT_DC And PTX 12 then uses the received P RECT_DC and internally determined P INV Determine efficiency E TRANSFER Alternatively, the PRX 24 can receive information about P from the PTX 12. INV Information, using P INV and P RECT_DC Determine E TRANSFER And report E to PTX 12 TRANSFER .

[0054] Power is a function of current and voltage. Therefore, the power at a given point within system 8 can be determined using current and / or voltage information. To obtain current and / or voltage information for calculating the power level, the measurement circuitry within each electronic device may include current sensors and / or voltage sensors. Figure 2 This illustrates how PTX 12 can include a voltage sensor 18A and / or a current sensor 18B. Information from these sensors can be used to determine the power level P of the inverter 26. INV. Figure 2 This illustrates how the PRX 24 can include a voltage sensor 42A and / or a current sensor 42B. Information from these sensors can be used to determine the power level P of the rectifier 50. RECT_DC .

[0055] Generally, current and / or voltage sensors at any desired location within system 8 (e.g., within power adapter 100, protective enclosure 98, inverter 26, and / or rectifier 50) can be used to determine current and / or voltage information at the desired location within system 8. The current and / or voltage information can then be used to determine the power level associated with the desired location within the system.

[0056] When reporting efficiency information to PTX 12, PRX 24 can report proxy information about the power level within system 8. Proxy information may include current and / or voltage information. As an example, PRX 24 can report efficiency information including the voltage V associated with rectifier 50. RECT_DC (For example, the voltage measured by voltage sensor 42A) and / or the current I associated with rectifier 50. RECT_DC (For example, the current measured by current sensor 42B). PTX 12 can use agent information V RECT_DC and / or I RECT_DC Determine P RECT_DC And then use P RECT_DC To determine the efficiency of wireless power transmission.

[0057] It should be noted that the values ​​of efficiency, power, current and / or voltage levels reported by PRX 24 can be averaged over a period of time. The duration of this period can be predetermined and / or adjustable in real time.

[0058] It should also be noted that, if desired, PTX 12 may report any desired efficiency information to PRX 24 (e.g., so that PRX 24 can take appropriate action based on real-time efficiency).

[0059] Figure 5A and Figure 5B These are cross-sectional side views of the WPT system 8 before and after the coil alignment process. (See attached image.) Figure 5A and Figure 5B As shown, the PTX 12 has a housing with a charging surface 30-S. The PRX 24 can be placed on the surface 30-S to initiate a wireless power charging session. The PRX 24 has a coil 48 inside the housing 52, while the PTX 12 has a coil 32 inside the housing 30. Figure 5A and Figure 5B In the middle, the Z-axis is parallel to the surface normal of the charging surface at 30-S.

[0060] exist Figure 5A In this case, when the PRX 24 is initially placed on the charging surface 30-S, coils 32 and 48 may be misaligned. Figure 5A As shown, coil 48 has a geometric center 48-C, and coil 32 has a geometric center 32-C. When centers 38-C and 32-C are aligned in the vertical direction (e.g., parallel to the Z-axis), the efficiency of wireless power transmission can be improved. However, Figure 5A The initial placement of PRX 24 resulted in a misalignment 206 between geometric center 32-C and geometric center 48-C.

[0061] PTX 12 may include a sensor layer 202-L positioned below the charging surface 30-S. The sensor layer 202-L may include one or more sensors 202 for detecting the position of the coil 48 in three-dimensional space. The sensor layer 202-L may determine the position of the coil 48 in the XY plane and optionally may determine the position of the coil 48 in the Z direction (e.g., the vertical offset of the coil 48 relative to the charging surface caused by the housing 52, intermediate accessories (such as the casing, etc.).

[0062] PTX 12 may include a positioning device 204 connected to coil 32. Positioning device 204 may be configured to move coil 32 in the XY plane to align coil 32 with the position of coil 48 detected by sensor layer 202-L.

[0063] Figure 5A The diagram illustrates how the positioning device 204 can move coil 32 in direction 207 (e.g., the negative X direction) to align coil 32 with the detected position of coil 48. After repositioning the coil, coil centers 32-C and 48-C can be aligned in the Z direction, as shown. Figure 5B As shown.

[0064] Figure 6 This is a top view of PTX 12, showing how coil 32 can move in the XY plane. Figure 6 As shown, coil 32 is positioned below charging surface 30-S. The area occupied by charging surface 30-S may be larger than the area occupied by coil 32, allowing coil 32 to move in the XY plane below the charging surface. Positioning device 204 can move coil 32 in any desired direction 208 in the XY plane to align coil 32 with a coil in the PRX device.

[0065] When no wireless power transfer is in progress between PTX 12 and PRX 24, the accuracy of the sensor layer 202-L in detecting the position of coil 48 can be improved. Therefore, when PRX 24 is placed on the charging surface of PTX 12, a coil alignment process can be performed before initiating a wireless power transfer session between PTX 12 and PRX 24. After the coil alignment process is completed, a wireless power transfer session can begin between PTX 12 and PRX 24.

[0066] Under ideal conditions, coils 32 and 48 remain aligned throughout the wireless power transfer session. However, in some cases, PTX 12 and / or PRX 24 may shift during the wireless power transfer session, resulting in misalignment between coils 32 and 48. This misalignment can undesirably reduce the efficiency of wireless power transfer. To improve efficiency, it is therefore desirable to realign coils 32 and 48 when misalignment occurs.

[0067] The first option for detecting misalignment between coil 32 and coil 48 is to pause the wireless power transfer session long enough to allow sensor layer 202-L to locate coil 48 and determine if coil 32 is still aligned with coil 48. However, this process may require the wireless power transfer session to be paused for a longer period than desired.

[0068] A second option for detecting misalignment between coil 32 and coil 48 is to monitor the efficiency of wireless power transmission during a wireless power transmission session. A calibration phase can be used to identify the expected efficiency under different operating conditions when the coils are aligned. Then, if the efficiency during the wireless power transmission session is lower than the expected efficiency under the current operating conditions, misalignment between the coils is detected, and a coil realignment process can be performed.

[0069] A third option for detecting misalignment between coil 32 and coil 48 is to estimate the inductive coupling factor (k) between PTX 12 and PRX 24 during a wireless power transfer session. If the estimated inductive coupling factor during a wireless power transfer session is lower than the baseline or the predicted inductive coupling factor, misalignment between the coils is detected, and a coil realignment process can be performed.

[0070] Figure 7 and Figure 8 Additional details are shown regarding the arrangement in which the efficiency of wireless power transmission is used to detect coil misalignment. Figure 7 This is a timeline showing the various operations of PTX 12 over time, and Figure 8 This is a flowchart illustrating an example method for operating PTX 12.

[0071] PRX 24 is available Figure 7The coil 48 is placed on the charging surface 30-S of the PTX 12 at position t0. The PTX 12 and / or PRX 24 can detect the placement of the PRX 24 on the charging surface 30-S and trigger a coil alignment process performed between t0 and t1. Between t0 and t1, the sensor 202 in the sensing layer 202-L can detect the position of the coil 48 on the charging surface 30-S. After detecting the position of the coil 48 on the charging surface 30-S, the positioning device 204 can move the coil 32 in the PTX 12 to align the centers of the coils 32 and 48 in a vertical direction (e.g., a direction orthogonal to the charging surface).

[0072] After the coils are aligned between t0 and t1, PTX 12 and PRX 24 may undergo a configuration and negotiation phase between t1 and t2. During the configuration and negotiation phase, PTX 12 and PRX 24 may exchange information using in-band and / or out-of-band communication. During configuration, PTX 12 may send identification information to identify PTX 12, information about PTX 12's capabilities (e.g., available power transfer frequency, power transfer level, operating mode, etc.), etc. Similarly, PRX 24 may send identification information to identify PRX 24, information about PRX 24's capabilities (e.g., available power transfer frequency, power transfer level, operating mode, etc.), status information (e.g., real-time state of charge information), etc.

[0073] During configuration, PTX 12 can perform a digital ping, where inverter 26 is turned on to send a low-level wireless power signal to PRX 24 using coil 32. In the absence of battery power for PRX 24 to operate, the digital ping can provide sufficient power to wake PRX 24. PRX 24 can use the wireless power received from the digital ping to transmit response packets to PTX 12 and continue configuration and negotiation operations. If the digital ping performed by PTX 12 does not produce a response from the compatible PRX 24, PTX 12 may abandon further wireless power transmission and will not initiate a wireless power transmission session. During the digital ping, rectifier 50 may not have an output load. Therefore, the digital ping operation may sometimes be referred to as occurring when PRX 24 and / or rectifier 50 have a “no-load” condition.

[0074] During the negotiation, PTX 12 and PRX 24 may negotiate the power transmission frequency of the wireless power signal transmitted by PTX 12 to PRX 24, the power level of the wireless power signal transmitted by PTX 12 to PRX 24, the power control profile of the wireless power transmission session, and / or other wireless power transmission and / or communication parameters.

[0075] After completing the configuration and negotiation phase at t2, PTX and PRX can begin a wireless power transfer session. A wireless power transfer session may include continuously transmitting wireless power at the negotiated power level and / or frequency (or the default power level and / or frequency).

[0076] When a wireless power transfer session (WPT session) begins, a calibration phase may exist between t2 and t3 to obtain baseline efficiency information associated with wireless power transfer between PTX 12 and PRX 24. The calibration phase may be performed at the start of the WPT session if the alignment between coil 32 and coil 48 (as set during the coil alignment process) can remain undisturbed.

[0077] During the calibration phase, PTX 12 can transmit wireless power to PRX 24 under various operating conditions. For example, PTX 12 can transmit wireless power to PRX 24 at various power levels (e.g., 7W, 9W, 11W, 13W, 15W, etc.). Additionally, PRX 24 can switch between different load conditions at the output of rectifier 50. The temperature of PTX 12 and / or PRX 24 can be recorded for each set of operating conditions during the calibration phase. The state of charge of PRX 24 can be recorded for each set of operating conditions during the calibration phase. The power transfer between PTX 12 and PRX 24 may have a unique efficiency for each set of operating conditions used during the calibration phase. As an example, a first efficiency E may exist under the first operating condition (e.g., 7W power level, low load condition). B1 A second efficiency E may exist under the second operating conditions (e.g., 11W power level, medium load conditions). B2 A third efficiency E may exist under the third operating conditions (e.g., 15W power level, high load conditions). B3 Generally, the efficiency of any desired number of operating conditions can be tested during the calibration phase. PTX 12 and / or PRX 24 can trigger and / or negotiate changes to operating conditions during the calibration phase.

[0078] It should be noted that, Figure 7 In this context, power transmission can continue throughout the calibration phase, and therefore, the calibration phase is considered a subset of the WPT session that is performed at the start of the WPT session. This example is merely illustrative, and in another possible naming convention, the calibration phase can be considered separate from the WPT session and can be performed after the configuration and negotiation phases and before the start of the WPT session.

[0079] After the calibration phase ends at t3, the WPT session can continue using a specific set of operating conditions negotiated by PTX 12 and / or PRX 24. Efficiency can then be checked periodically throughout the WPT session. Figure 7It shows how to perform the first efficiency check at t4, the second efficiency check at t5, and the third efficiency check at t6, etc.

[0080] For each efficiency check, the efficiency of wireless power transfer between PTX 12 and PRX 24 is determined by PTX 12. For example, PTX 12 can determine that a first efficiency E exists at t4. R1 (Sometimes referred to as real-time efficiency), a second efficiency E exists at t5. R2 There exists a third efficiency E at t6. R3 Each time real-time efficiency is checked, it can be compared to the baseline efficiency information obtained during the calibration phase. The comparison between real-time efficiency and baseline efficiency information can indicate whether the coil has become misaligned.

[0081] Consider an example where, during the calibration phase (assuming coil alignment), power delivery of 15W has 80% efficiency under high load conditions and 78% efficiency under medium load conditions. Between t3 and t4, the PTX 12 can deliver 15W of power under high load conditions. The measured efficiency E R1 It can be 80%. This real-time efficiency matches the baseline efficiency from the same operating conditions during the calibration phase, and therefore, the PTX 12 can determine that the coil is still aligned at t4. Between t4 and t5, the PTX 12 can deliver 11W of power under medium load conditions. Measured efficiency E R2 It can be 78%. This real-time efficiency matches the baseline efficiency from the same operating conditions during the calibration phase, and therefore, the PTX 12 can determine that the coil is still aligned at t5. The baseline efficiency information from the calibration phase allows the PTX 12 to identify that the efficiency drop from 80% to 78% between t4 and t5 is likely caused by a change in power level and / or load conditions (rather than coil misalignment). Between t5 and t6, the PTX 12 can deliver 11W of power under medium load conditions. Measured efficiency E R3 It could be 76%. This real-time efficiency is lower than the baseline efficiency from the same operating conditions during the calibration phase, and therefore, the PTX 12 can determine that the coil is misaligned. The baseline efficiency information from the calibration phase allows the PTX 12 to identify that the efficiency drop from 78% to 76% between t5 and t6 may be caused by coil misalignment.

[0082] In summary, the efficiency under different operating conditions during the calibration phase allows PTX 12 to estimate the expected efficiency of a given set of operating conditions for real-time efficiency checks during the WPT session. It should be noted that any desired technique can be used with any desired number of real-time operating conditions to estimate the expected efficiency. When the real-time efficiency is lower than the expected efficiency by a given amount (e.g., greater than 0.1%, greater than 0.5%, greater than 1%, greater than 2%, etc.), PTX 12 can determine that coils 32 and 48 are misaligned.

[0083] After PTX 12 determines that the coil is misaligned at t6, PTX 12 can initiate a coil realignment process that is completed between t6 and t7. Between t6 and t7, power transfer between PTX 12 and PTX 24 can be paused. During the power transfer pause, sensor 202 in sensing layer 202-L can detect the new position of coil 48 on charging surface 30-S. After detecting the new position of coil 48 on charging surface 30-S, positioning device 204 can move coil 32 in PTX 12 to align the centers of coils 32 and 48 in the vertical direction.

[0084] After the coil is aligned between t6 and t7, the WPT session can resume, and efficiency checks can be performed intermittently again to continuously monitor coil alignment.

[0085] Pausing power transfer during coil realignment is sometimes referred to as masking. After the masking period is complete (e.g., at t7), the WPT session can resume using the operating parameters that were in place at the start of the masking period (e.g., the same operating parameters from before the masking period). Masking allows coil realignment to be performed with high accuracy without having to repeat the configuration and negotiation phases and calibration phases after coil realignment is complete. Alternatively, the configuration and negotiation phases and / or calibration phases can be performed after coil realignment is complete, if desired.

[0086] It should be noted that the duration of the masking period allowing coil realignment can be negotiated by PTX 12 and / or PRX 24 during the configuration and negotiation phase. Similarly, the frequency of repeating efficiency checks can be negotiated by PTX 12 and / or PRX 24 during the configuration and negotiation phase. As an example, efficiency checks can be performed at regular intervals such as once per minute, once every thirty seconds, once every two minutes, etc. Alternatively or additionally, efficiency checks can be performed at irregular intervals. Efficiency checks can be triggered by input to one or more input-output devices in PTX 12 and / or PRX 24. As an example, input-output device 54 in PRX 24 may include an accelerometer that detects movement of PRX 24. When the accelerometer in PRX 24 detects movement of PRX 24, PRX 24 can trigger an efficiency check in PTX 12. Similarly, input-output device 28 in PTX 12 may include an accelerometer that detects movement of PTX 12. When the accelerometer in PTX 12 detects movement of PTX 12, PTX 12 can trigger an efficiency check. Generally, any expected input (especially those associated with possible coil misalignment) can be used to trigger the efficiency check.

[0087] Figure 8 This is a flowchart illustrating an example method for operating PTX 12. Figure 8 The operation can be performed by control circuitry 16 in PTX 12. During operation of block 302, control circuitry 16 can align the wireless power delivery coil 32 with the sensed position of the wireless power delivery coil 48 in PTX 24. Aligning coil 32 with coil 48 may include using (e.g., in...) Figure 5A and Figure 5B The sensor 202 in the sensor layer 202-L senses the position of the coil 48, and then the positioning device 204 is used to move the coil 32 to align with the sensed position.

[0088] Next, during the operation of box 304, PTX 12 may exchange configuration information and / or negotiate operating parameters with PRX 24. The exchanged configuration information may include exchanging device identification information, power transmission capability information, status information, etc. The negotiated operating parameters may include negotiating the power transmission frequency, power transmission level, masking duration, and the frequency used for efficiency checks during the wireless power transmission session, etc.

[0089] During operation of block 306, PTX 12 can perform efficiency calibration, whereby a baseline efficiency is determined for different operating conditions. Specifically, the baseline efficiency can be determined for different wireless power transmission levels, load conditions, temperature, PRX state of charge (SOC), etc. Operation of block 306 can be performed at the start of a wireless power transmission session (e.g., immediately at the start of a WPT session) to maximize the likelihood of alignment between coils 32 and 48 during the calibration phase.

[0090] During the operation of box 308, PTX 12 may receive efficiency information from PRX 24. As previously discussed, the received efficiency information may be an efficiency measurement or information that can be used to calculate efficiency.

[0091] During the operation of box 310, PTX 12 may take appropriate action based on received efficiency information (from box 308) and baseline efficiency information (from box 306). The operation of box 310 may include determining the expected efficiency based on real-time operating conditions (e.g., real-time temperature, power delivery level, PRX load conditions, PRX SOC, etc.) and comparing the real-time efficiency (obtained from the efficiency information received from box 308) with the expected efficiency.

[0092] When the real-time efficiency is significantly lower than the expected efficiency by a threshold amount, the PTX 12 can pause the wireless transmission session to realign the coils, as shown in the operation of block 312. While realigning coils 32 and 48 during the operation of block 312, the PTX 12 can use (e.g., in...) Figure 5A and Figure 5B The sensor 202 in the sensor layer 202-L senses the position of the coil 48, and then the positioning device 204 is used to move the coil 32 to align it with the sensed position. The duration of the pause for coil realignment in block 312 can be greater than 100 milliseconds, greater than 1 second, greater than 10 seconds, greater than 20 seconds, greater than 30 seconds, etc.

[0093] When the difference between the real-time efficiency and the expected efficiency is less than a threshold amount, the PTX 12 can continue the wireless power transfer session, as shown in the operation of box 314. The threshold amount can be greater than 0.1%, greater than 0.5%, greater than 1%, greater than 2%, etc. The PTX can repeat the operations of boxes 308 and 310 at regular frequencies to continuously evaluate coil alignment throughout the wireless power transfer session. The PTX 12 can optionally repeat the operations of boxes 308 and 310 intermittently at irregular intervals based on inputs to one or more input devices in the PTX 12 and / or PRX 24.

[0094] Other suitable actions that may be performed at box 310 may include (e.g., providing audio or visual notifications via displays in PTX 12 and / or PRX 24 or speakers in PTX 12 and / or PRX 24), stopping wireless power transmission sessions, etc.

[0095] Figure 8 The order of operations is only illustrative, and in general, the operations in boxes 302 to 310 can be performed in any desired order.

[0096] Figure 9 and Figure 10 Additional details are shown regarding the arrangement in which an estimate of the inductive coupling factor is used to detect coil misalignment. Figure 9 This is a timeline showing the various operations of PTX 12 over time, and Figure 10 This is a flowchart illustrating an example method for operating PTX 12.

[0097] PRX 24 is available Figure 9 The t0 point is placed on the charging surface 30-S of PTX 12. PTX 12 can perform a coil alignment process between t0 and t1 (as previously combined). Figure 7 (As discussed). After the coils are aligned between t0 and t1, PTX 12 and PRX 24 can undergo a configuration and negotiation phase between t1 and t2 (as previously discussed). Figure 7 (As discussed).

[0098] Additionally, during the configuration and negotiation phase, PTX 12 can estimate the magnitude of the inductive coupling factor (k) between PTX 12 and PRX 24. The inductive coupling factor k is equal to... Where M' is mutual inductance, L' TX It is the inductance of coil 32, and L' RX It is the inductance of coil 48. To estimate k during the configuration and negotiation phases, PRX 24 can perform low-level wireless power transfers from PTX 12 to PRX 24 during digital ping (e.g., at the start of the configuration phase and when PRX 24 is detected on PTX 12, during low-level wireless power transfers). Figure 2 The voltage sensor 42A in the middle measures the output voltage (V) of the rectifier. RECT_DC The rectifier output voltage during digital ping is sometimes referred to as the digital ping voltage. The digital ping voltage can be measured by PRX 24 and reported to PTX 12 (e.g., using in-band or out-of-band communication). PRX 24 can also send one or more additional coefficients (e.g., scaling factors) or parameters to PTX 12 to assist PTX 12 in estimating the inductive coupling factor. PTX 12 can use the received information to estimate the magnitude of k (e.g., ...). Where kest is an estimator of k. V RECT_DC It is the digital ping voltage, V IN VCTX_PP is the input voltage of inverter 26, VCTX_PP is the measured peak-to-peak voltage across tuning capacitor 70, and E0 and E1 are selected to fit the k-estimation formula within a preference range from 0.72 to 0.88.

[0099] After completing the configuration and negotiation phase at t2, PTX and PRX can begin a wireless power transfer session. A wireless power transfer session may include continuously transmitting wireless power at the negotiated power level and / or frequency (or the default power level and / or frequency).

[0100] After the start of the wireless power transfer session (WPT session), the PTX 12 can repeatedly estimate the inductive coupling factor in order to assess the alignment between coil 32 and coil 48. Figure 9 An example is shown where the inductive coupling factor is estimated for the first time between t3 and t4, the second time between t5 and t6, and the third time between t7 and t8. Each time k estimation is performed, the estimated value of k is compared with the baseline estimate of k obtained during the configuration phase. The comparison between the real-time k estimate and the baseline k estimate indicates whether the coil has become misaligned.

[0101] Consider an example where, during the configuration phase (assuming coil alignment), PTX estimates the value of k to be 0.8. In the first k estimation, PTX can estimate the value of k to be 0.8. This real-time k estimate matches the baseline k estimate, and therefore, PTX 12 can determine that the coil is still aligned at t4. In the second k estimation, PTX can estimate the value of k to be 0.79. This real-time k estimate is within a threshold difference between the real-time k estimate and the baseline k estimate, and therefore, PTX 12 can determine that the coil is still aligned at t6. In the third k estimation, PTX can estimate the value of k to be 0.77. This real-time k estimate is greater than the threshold difference between the real-time k estimate and the baseline k estimate, and therefore, PTX 12 can determine that the coil is misaligned at t8.

[0102] In summary, monitoring the k-estimate over time allows for the detection of coil misalignment. When the real-time k-estimate differs from the baseline k-estimate by a given amount (e.g., greater than 0.01, 0.02, 0.03, 0.05, etc.), PTX 12 can determine that coils 32 and 48 have become misaligned. Alternatively, the real-time k-estimate can be compared to a threshold (e.g., 0.78) instead of the baseline k-estimate. When the real-time k-estimate is less than the threshold, PTX 12 can determine that coils 32 and 48 have become misaligned. The threshold can have any desired value. If desired, the threshold can be determined based on real-time operating conditions (e.g., temperature, power delivery level, PRX load conditions, PRX SOC, etc.).

[0103] After PTX 12 determines that the coil is misaligned at t8, PTX 12 can initiate a coil realignment process that is completed between t8 and t9. Between t8 and t9, power transfer between PTX 12 and PTX 24 can be paused. During the power transfer pause, sensor 202 in sensing layer 202-L can detect the new position of coil 48 on charging surface 30-S. After detecting the new position of coil 48 on charging surface 30-S, positioning device 204 can move coil 32 in PTX 12 to align the centers of coil 32 and 48 in the vertical direction (orthogonal to the charging surface).

[0104] After the coil is aligned between t8 and t9, the WPT session can resume, and k estimation can be performed intermittently again to continuously monitor coil alignment.

[0105] There are several ways to estimate the inductive coupling factor during each k estimation period. One technique is to pause the wireless power transmission session and use digital ping to estimate k. In other words, the same process used to estimate k during the configuration and negotiation phases can be used for each k estimation during the wireless power transmission session.

[0106] When k-estimation is performed using digital ping during a wireless power transmission session, the wireless power transmission session is paused, making it possible to obtain the k-estimation using digital ping (as previously described). During digital ping, rectifier 50 may not have an output load. Therefore, digital ping operations are sometimes referred to as occurring when PRX 24 and / or rectifier 50 have a “no-load” condition.

[0107] The pause for k-estimation using digital ping can be triggered by PTX 12 and / or PRX 24. For example, PTX 12 can send a notification to PRX 24 that radio power transmission operation is about to be paused for k-estimation operation. Alternatively, PRX 24 can send a request to PTX 12 to pause radio power transmission operation for k-estimation operation. The pause for k-estimation can last for the duration negotiated during the configuration and negotiation phases. The duration required for k-estimation can be less than the duration required for coil alignment. Therefore, PTX 12 and PRX 24 can negotiate a first duration for the pause used for k-estimation and a second duration longer than the first duration for the pause used for coil alignment. The first duration can be less than 5 seconds, less than 3 seconds, less than 2 seconds, less than 1 second, etc. The second duration can be greater than 100 milliseconds, greater than 1 second, 10 seconds, greater than 20 seconds, greater than 30 seconds, etc. The second duration can be at least 3 seconds, at least 5 seconds, at least 10 seconds, at least 20 seconds, etc., longer than the first duration. The second duration can be at least 3 times, at least 5 times, at least 10 times, etc. of the first duration.

[0108] Using a digital ping operation to estimate k requires pausing the wireless power transmission session. Although a low level of wireless power is briefly transmitted during a digital ping operation, the digital ping operation is not considered part of a dedicated wireless power transmission session. To avoid pausing the wireless power transmission session for k estimation, k estimation can instead be performed during the wireless power transmission session while the PRX 24 operates under low load conditions. At the beginning of each k estimation period (e.g., at...) Figure 9 At t3, t5, and t7 in the equation, PRX 24 can set (e.g., reduce) the rectifier output load to a non-zero value. For consistency, the same non-zero value can optionally be used for each k-estimation. This operating mode of PRX 24 and rectifier 50 can be referred to as a "low load" condition. PRX 24 can switch to the low load condition for each k-estimation cycle. Outside of the k-estimation cycle, PRX 24 can operate under medium or high load conditions during a wireless power transfer session. In general, PRX 24 can be capable of operating under a variety of load conditions. PRX 24 can select the appropriate load condition based on the real-time operating parameters of PTX 12 and / or PRX 24. However, PRX 24 can switch to the same load condition (e.g., low load condition) for each k-estimation, regardless of the real-time operating parameters.

[0109] As an example, the real-time operating parameters of PTX 12 and PRX 24 can be compared with... Figure 9The high load conditions between t2 and t7 are associated with this. Therefore, when k estimation is not performed (e.g., between t2 and t3, between t4 and t5, and between t6 and t7), the PRX24 operates under high load conditions during a wireless power transfer session. However, when k estimation is performed (e.g., between t3 and t4, and between t5 and t6), the load conditions associated with k estimation take precedence, and the PRX 24 operates under low load conditions.

[0110] It should be noted that the same formula used to estimate k during digital ping operations can also be used to estimate k during low-load conditions (e.g., Where kest is an estimator of k. V RECT_DC This is the voltage reported by PRX 24 during low load conditions, V. IN VCTX_PP is the input voltage of inverter 26, VCTX_PP is the measured peak-to-peak voltage across tuning capacitor 70, and E0 and E1 are selected to fit the k-estimation formula within a preference range from 0.72 to 0.88.

[0111] If desired, the power level of the wireless power transmitted by the PTX 12 can be reduced during the k-estimation period. As an example, the real-time operating parameters of the PTX 12 and PRX 24 can be compared with... Figure 9 The 15W power transfer level is associated with t2 and t7. Therefore, when k estimation is not performed (e.g., between t2 and t3, between t4 and t5, and between t6 and t7), the PTX 12 operates at 15W during a wireless power transfer session. However, when k estimation is performed (e.g., between t3 and t4, and between t5 and t6), the PTX 12 can reduce the power level (e.g., to 5W).

[0112] The frequency of repeated k-estimation during a wireless power transfer session can be negotiated by PTX 12 and / or PRX 24 during the configuration and negotiation phase. As an example, k-estimation can be performed at regular intervals such as once per minute or more, once every thirty seconds or more, once every two minutes or more, etc. Alternatively or additionally, k-estimation can be performed at irregular intervals. k-estimation can be triggered by input to one or more input-output devices in PTX 12 and / or PRX 24. As an example, input-output device 54 in PRX 24 may include an accelerometer that detects movement of PRX 24. When the accelerometer in PRX 24 detects movement of PRX 24, PRX 24 can trigger k-estimation in PTX 12. Similarly, input-output device 28 in PTX 12 may include an accelerometer that detects movement of PTX 12. When the accelerometer in PTX 12 detects movement of PTX 12, PTX 12 can trigger k-estimation. Generally speaking, any desired input (especially those associated with possible coil misalignment) can be used to trigger k estimation.

[0113] Figure 10 This is a flowchart illustrating an example method for operating PTX 12. Figure 10 The operation can be performed by control circuitry 16 in PTX 12. During operation of block 322, control circuitry 16 can align the wireless power delivery coil 32 with the sensed position of the wireless power delivery coil 48 in PTX 24. Aligning coil 32 with coil 48 may include using (e.g., in...) Figure 5A and Figure 5B The sensor 202 in the sensor layer 202-L senses the position of the coil 48, and then the positioning device 204 is used to move the coil 32 to align with the sensed position.

[0114] Next, during the operation of box 324, PTX 12 may exchange configuration information and / or negotiate operating parameters with PRX 24. Exchanging configuration information may include exchanging device identification information, power transmission capability information, status information, etc. During the configuration phase, PTX 12 may estimate the baseline inductive coupling factor between PTX 12 and PRX 24. Negotiating operating parameters may include negotiating the power transmission frequency, power transmission level, first masking duration for k-estimation, second masking duration for coil realignment, and the frequency for k-estimation during the wireless power transmission session, etc.

[0115] During the operation of box 326, PTX 12 can estimate the inductive coupling factor (k) between PTX 12 and PRX 24. Estimating the inductive coupling factor may include pausing the wireless power transmission session to estimate the inductive coupling factor using a digital ping operation, as shown in the operation of box 328. The duration of the pause used for k estimation may be less than 5 seconds, less than 3 seconds, less than 1 second, etc. Estimating the inductive coupling factor may also include reducing the rectifier output load in PRX 24 to a non-zero value to estimate the inductive coupling factor, as shown in the operation of box 330. The duration of the low-load mode used for k estimation may be less than 5 seconds, less than 3 seconds, less than 1 second, etc.

[0116] During the operation of box 332, PTX 12 may take appropriate action based on the estimated inductive coupling factor from box 326. The operation of box 332 may include comparing the estimated inductive coupling factor from box 326 with a baseline inductive coupling factor estimated during box 324. Alternatively or additionally, the operation of box 332 may include comparing the estimated inductive coupling factor from box 326 with a predicted inductive coupling factor predicted based on the baseline inductive coupling factor and one or more additional real-time operating parameters of PTX 12 and / or PRX 24.

[0117] When the estimated inductive coupling factor from block 326 is lower than the baseline inductive coupling factor and / or the predicted inductive coupling factor, control circuitry 16 can determine that coils 32 and 48 are misaligned. When coils 32 and 48 are determined to be misaligned, PTX 12 can pause the wireless transmission session to realign the coils, as shown in the operation of block 334. While realigning coils 32 and 48 during the operation of block 334, PTX 12 can use (e.g., in...) Figure 5A and Figure 5B The sensor 202 in the sensor layer 202-L senses the position of the coil 48, and then the positioning device 204 is used to move the coil 32 to align with the sensed position. The duration of the pause for coil realignment in block 334 can be greater than 100 milliseconds, greater than 1 second, greater than 10 seconds, greater than 20 seconds, greater than 30 seconds, etc.

[0118] When the estimated inductive coupling factor from block 326 is greater than or equal to the baseline inductive coupling factor and / or the predicted inductive coupling factor, or the difference between the estimated inductive coupling factor and the baseline inductive coupling factor and / or the predicted inductive coupling factor is within a threshold range, control circuit 16 can determine that coils 32 and 48 are aligned. When coils 32 and 48 are determined to be sufficiently aligned, PTX 12 can continue the wireless power transfer session as shown in the operation of block 336.

[0119] Other suitable actions that may be performed at box 332 may include (e.g., providing audio or visual notifications via displays in PTX 12 and / or PRX 24 or speakers in PTX 12 and / or PRX 24), stopping wireless power transmission sessions, etc.

[0120] The PTX 12 can repeat the operations of boxes 326 and 332 at regular frequencies to continuously evaluate coil alignment throughout the wireless power transfer session. The PTX 12 can optionally repeat the operations of boxes 326 and 332 intermittently at irregular intervals based on inputs to one or more input devices in the PTX 12 and / or PRX 24.

[0121] Figure 10 The order of operations is only illustrative, and in general, the operations in boxes 322 to 336 can be performed in any desired order.

[0122] According to one embodiment, an electronic device is configured to transmit wireless power with an attached electronic device, and the electronic device includes: a wireless power transmission coil; an inverter configured to supply an AC drive signal to the wireless power transmission coil; a positioning device configured to move the wireless power transmission coil; and a control circuit configured to: after the start of a wireless power transmission session, cause a first pause of the wireless power transmission session for a first duration; during the first pause, determine an inductive coupling factor between the electronic device and the attached electronic device; based on the inductive coupling factor, cause a second pause of the wireless power transmission session for a second duration, the second duration being greater than the first duration; and during the second pause, use the positioning device to move the wireless power transmission coil.

[0123] According to another embodiment, inducing a second pause based on an inductive coupling factor may optionally include: inducing a second pause based on determining that the inductive coupling factor is below a threshold inductive coupling factor.

[0124] According to another embodiment, the control circuit is optionally configured to: determine a baseline inductive coupling factor between an electronic device and an additional electronic device before the start of a wireless power transmission session, wherein inducing a second pause based on the inductive coupling factor includes: inducing a second pause based on determining that the inductive coupling factor has decreased by more than a threshold amount relative to the baseline inductive coupling factor.

[0125] According to another embodiment, the control circuit is optionally configured to repeatedly: cause a first pause of the wireless power transmission session for a first duration during the wireless power transmission session; and determine the inductive coupling factor between the electronic device and the attached electronic device during the first pause.

[0126] According to another embodiment, determining the inductive coupling factor may optionally include using a digital ping voltage reported by an additional electronic device to determine the inductive coupling factor.

[0127] According to another embodiment, the electronic device may optionally include: a charging surface; and one or more sensors configured to determine the position of an additional wireless power transmission coil in the additional electronic device on the charging surface.

[0128] According to another embodiment, using a positioning device to move the wireless power transfer coil during the second pause may optionally include: using one or more sensors to determine a first position of the additional wireless power transfer coil on the charging surface; and moving the wireless power transfer coil to align with the first position of the additional wireless power transfer coil.

[0129] According to another embodiment, the control circuit is optionally configured to, before initiating wireless power transfer operation, use one or more sensors to determine a second position of the additional wireless power transfer coil on the charging surface; and move the wireless power transfer coil to align with the second position of the additional wireless power transfer coil.

[0130] According to one embodiment, an electronic device is configured to transmit wireless power with an attached electronic device, and includes: a wireless power transmission coil; an inverter configured to supply an AC drive signal to the wireless power transmission coil; a positioning device configured to move the wireless power transmission coil; and a control circuit configured to: during a wireless power transmission session, identify that the attached electronic device has reduced the rectifier output load to a non-zero value; determine an inductive coupling factor between the electronic device and the attached electronic device when the rectifier output load in the attached electronic device has a non-zero value; and use the positioning device to move the wireless power transmission coil based on the inductive coupling factor.

[0131] According to another embodiment, moving the wireless power transmission coil based on the inductive coupling factor may optionally include: moving the wireless power transmission coil based on the inductive coupling factor after determining that the inductive coupling factor is below a threshold inductive coupling factor.

[0132] According to another embodiment, the non-zero value of the rectifier output load may optionally be less than the target rectifier output load associated with the real-time operating characteristics of the additional electronic equipment.

[0133] According to another embodiment, identifying that the additional electronic device has reduced the rectifier output load to a non-zero value may optionally include: sending an instruction to the additional electronic device to cause the additional electronic device to reduce the rectifier output load to a non-zero value.

[0134] According to another embodiment, identifying that the additional electronic device has reduced the rectifier output load to a non-zero value may optionally include receiving information from the additional electronic device indicating that the additional electronic device is reducing the rectifier output load to a non-zero value.

[0135] According to another embodiment, the electronic device may optionally include: a charging surface; and one or more sensors configured to determine the position of an additional wireless power transmission coil in the additional electronic device on the charging surface.

[0136] According to another embodiment, using a positioning device to move the wireless power transfer coil based on an inductive coupling factor may optionally include: using one or more sensors to determine a first position of the additional wireless power transfer coil on the charging surface; and moving the wireless power transfer coil to align with the first position of the additional wireless power transfer coil.

[0137] According to another embodiment, the control circuit is optionally configured to, before starting a wireless power transfer session: use one or more sensors to determine a second position of the additional wireless power transfer coil on the charging surface; and move the wireless power transfer coil to align with the second position of the additional wireless power transfer coil.

[0138] According to one embodiment, an electronic device is configured to transmit wireless power with an attached electronic device and includes: a wireless power transmission coil; an inverter configured to supply an AC drive signal to the wireless power transmission coil; a positioning device configured to move the wireless power transmission coil; and a control circuit configured to: collect baseline efficiency information during wireless power transmission with the attached electronic device during a calibration phase of a wireless power transmission session; receive efficiency information from the attached electronic device during wireless power transmission with the attached electronic device during the wireless power transmission session; and use the positioning device to move the wireless power transmission coil based on the baseline efficiency information and the efficiency information from the attached electronic device.

[0139] According to another embodiment, collecting baseline efficiency information during the calibration phase may optionally include: determining efficiency values ​​at multiple power levels for wireless power transfer between the electronic device and the attached electronic device.

[0140] According to another embodiment, collecting baseline efficiency information during the calibration phase may optionally include: determining efficiency values ​​under multiple load conditions for wireless power transfer between the electronic device and an additional electronic device.

[0141] According to another embodiment, using a positioning device to move a wireless power transmission coil based on baseline efficiency information and efficiency information from an attached electronic device may optionally include: using the baseline efficiency information to determine an efficiency threshold based on a current set of operating conditions; comparing an efficiency value indicated by the efficiency information from the attached electronic device with the efficiency threshold; and using the positioning device to move the wireless power transmission coil if the determined efficiency value is less than the efficiency threshold.

[0142] According to another embodiment, the electronic device may optionally include: a charging surface; and one or more sensors configured to determine the position of an additional wireless power transmission coil in the additional electronic device on the charging surface.

[0143] According to another embodiment, using a positioning device to move the wireless power transfer coil, based on baseline efficiency information and efficiency information from an additional electronic device, optionally includes: using one or more sensors to determine a first position of the additional wireless power transfer coil on the charging surface; and moving the wireless power transfer coil to align with the first position of the additional wireless power transfer coil.

[0144] According to another embodiment, the control circuit is optionally configured to, before starting a wireless power transfer session: use one or more sensors to determine a second position of the additional wireless power transfer coil on the charging surface; and move the wireless power transfer coil to align with the second position of the additional wireless power transfer coil.

[0145] The foregoing is merely illustrative and various modifications can be made to the described implementation scheme. The foregoing implementation scheme can be implemented individually or in any combination.

Claims

1. An electronic device configured to transmit wireless power with an attached electronic device, the electronic device comprising: Wireless power transfer coil; An inverter configured to supply an AC drive signal to the wireless power transmission coil; A positioning device configured to move the wireless power transmission coil; and Control circuit, the control circuit being configured to: After the wireless power transmission session begins, a first pause of the wireless power transmission session is caused for a first duration; During the first pause, the inductive coupling factor between the electronic device and the additional electronic device is determined; Based on the inductive coupling factor, a second pause in the wireless power transmission session is caused for a second duration, the second duration being longer than the first duration; as well as During the second pause, the positioning equipment is used to move the wireless power transmission coil.

2. The electronic device of claim 1, wherein inducing the second pause based on the inductive coupling factor comprises: The second pause is triggered by determining that the inductive coupling factor is below a threshold inductive coupling factor.

3. The electronic device according to claim 1, wherein the control circuit is further configured to: Before the wireless power transmission session begins, a baseline inductive coupling factor is determined between the electronic device and the attached electronic device, wherein inducing the second pause based on the inductive coupling factor includes: The second pause is triggered by determining that the inductive coupling factor has decreased by more than a threshold amount relative to the baseline inductive coupling factor.

4. The electronic device of claim 1, wherein the control circuitry is configured to repeatedly: The first pause that caused the wireless power transmission session lasted for the first duration; and During the first pause, the inductive coupling factor between the electronic device and the additional electronic device is determined.

5. The electronic device of claim 1, wherein determining the inductive coupling factor comprises: The inductive coupling factor is determined using the digital ping voltage reported by the additional electronic device.

6. The electronic device according to claim 1, further comprising: Charging surface; and One or more sensors are configured to determine the position of an additional wireless power transmission coil in the additional electronic device on the charging surface.

7. The electronic device of claim 6, wherein using the positioning device to move the wireless power transmission coil during the second pause comprises: The one or more sensors are used to determine the first position of the additional wireless power transfer coil on the charging surface; as well as Move the wireless power transmission coil to align it with the first position of the additional wireless power transmission coil.

8. The electronic device of claim 7, wherein the control circuitry is configured to: before initiating wireless power transfer operation: The one or more sensors are used to determine a second position of the additional wireless power transfer coil on the charging surface; and Move the wireless power transmission coil to align it with the second position of the additional wireless power transmission coil.

9. An electronic device configured to transmit wireless power with an attached electronic device, the electronic device comprising: Wireless power transfer coil; An inverter configured to supply an AC drive signal to the wireless power transmission coil; A positioning device configured to move the wireless power transmission coil; and Control circuit, the control circuit being configured to: During a wireless power transfer session, it is indicated that the additional electronic device has reduced the rectifier output load to a non-zero value; When the rectifier output load in the additional electronic device has the non-zero value, the inductive coupling factor between the electronic device and the additional electronic device is determined; as well as Based on the inductive coupling factor, the positioning equipment is used to move the wireless power transmission coil.

10. The electronic device of claim 9, wherein moving the wireless power transmission coil based on the inductive coupling factor comprises: Based on the determination that the inductive coupling factor is below a threshold inductive coupling factor, the wireless power transmission coil is moved according to the inductive coupling factor.

11. The electronic device of claim 9, wherein the non-zero value of the rectifier output load is less than the target rectifier output load associated with the real-time operating characteristics of the additional electronic device.

12. The electronic device of claim 9, wherein identifying that the additional electronic device has reduced the rectifier output load to the non-zero value includes: Send an instruction to the additional electronic device to cause the additional electronic device to reduce the rectifier output load to the non-zero value.

13. The electronic device of claim 9, wherein identifying that the additional electronic device has reduced the rectifier output load to the non-zero value includes: The additional electronic device receives information indicating that it is reducing the rectifier output load to the non-zero value.

14. The electronic device according to claim 9, further comprising: Charging surface; and One or more sensors are configured to determine the position of an additional wireless power transmission coil in the additional electronic device on the charging surface.

15. The electronic device of claim 14, wherein moving the wireless power transmission coil using the positioning device based on the inductive coupling factor comprises: The one or more sensors are used to determine the first position of the additional wireless power transfer coil on the charging surface; as well as Move the wireless power transmission coil to align it with the first position of the additional wireless power transmission coil.

16. The electronic device of claim 15, wherein the control circuitry is configured to: before initiating the wireless power transmission session. The one or more sensors are used to determine a second position of the additional wireless power transfer coil on the charging surface; and Move the wireless power transmission coil to align it with the second position of the additional wireless power transmission coil.

17. An electronic device configured to transmit wireless power with an attached electronic device, the electronic device comprising: Wireless power transfer coil; An inverter configured to supply an AC drive signal to the wireless power transmission coil; A positioning device configured to move the wireless power transmission coil; and Control circuit, the control circuit being configured to: During the calibration phase of the wireless power transmission session, baseline efficiency information is collected while transmitting the wireless power with the attached electronic device; During the wireless power transmission session, efficiency information is received from the attached electronic device while transmitting the wireless power with the attached electronic device; as well as Based on the baseline efficiency information and the efficiency information from the additional electronic device, the positioning equipment is used to move the wireless power transmission coil.

18. The electronic device of claim 17, wherein collecting the baseline efficiency information during the calibration phase comprises: Efficiency values ​​are determined at multiple power levels for wireless power transfer between the electronic device and the additional electronic device.

19. The electronic device of claim 18, wherein collecting the baseline efficiency information during the calibration phase comprises: Determine efficiency values ​​for wireless power transfer between the electronic device and the additional electronic device under multiple load conditions.

20. The electronic device of claim 17, wherein moving the wireless power transmission coil using the positioning device based on the baseline efficiency information and the efficiency information from the additional electronic device comprises: Using the baseline efficiency information, an efficiency threshold is determined based on the current set of operating conditions; The efficiency value indicated by the efficiency information from the attached electronic device is compared with the efficiency threshold. as well as Based on the determination that the efficiency value is less than the efficiency threshold, the positioning equipment is used to move the wireless power transmission coil.

21. The electronic device according to claim 17, further comprising: Charging surface; and One or more sensors are configured to determine the position of an additional wireless power transmission coil in the additional electronic device on the charging surface.

22. The electronic device of claim 21, wherein moving the wireless power transmission coil using the positioning device based on the baseline efficiency information and the efficiency information from the additional electronic device comprises: The one or more sensors are used to determine the first position of the additional wireless power transfer coil on the charging surface; as well as Move the wireless power transmission coil to align it with the first position of the additional wireless power transmission coil.

23. The electronic device of claim 22, wherein the control circuitry is configured to: before initiating the wireless power transmission session: The one or more sensors are used to determine a second position of the additional wireless power transfer coil on the charging surface; and Move the wireless power transmission coil to align it with the second position of the additional wireless power transmission coil.

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