Methods for wireless power transmission through a medium

Abstract

A method of wireless power transfer through a medium is provided. The method includes controlling an input voltage of an inverter of a transmitter of a wireless power transfer system based on a detected parameter. The method further includes generating, by the transmitter, a field for wirelessly transferring power through the medium to a receiver of the wireless power transfer system based on the input voltage. Other methods are also provided. A controller, system, and transmitter for wirelessly transferring power through a medium are also provided.

Description

[Technical Field]

[0001] The present disclosure relates generally to wireless power transfer, and more particularly to a method of wireless power transfer through a medium and a controller for wirelessly transferring power through a medium. [Background technology]

[0002] Wireless power transfer systems, such as wireless charging, are becoming an increasingly important technology for powering the next generation of devices. The potential benefits and advantages offered by this technology are evident as more and more manufacturers and companies invest in this technology.

[0003] Various wireless power transfer systems are known. A typical wireless power transfer system includes a power source electrically connected to a wireless power transmitter and a wireless power receiver electrically connected to a load.

[0004] In a magnetic induction system, the transmitter has a transmitter coil with an inductance that transfers electrical energy from a power source to a receiver, and the receiver has a receiver coil with an inductance. Power transfer occurs through magnetic field coupling between the transmitter and receiver coils or inductors. These magnetic induction systems have a limited range, and the transmitter and receiver coils or inductors must be tightly coupled, i.e., have a coupling coefficient greater than 0.5, and be optimally aligned for efficient power transfer.

[0005] There are also resonant magnetic systems in which power is transferred by magnetic field coupling between the coils or inductors of the transmitter and receiver. The transmitter and receiver inductors may be loosely coupled, i.e., have a coupling coefficient below 0.5. However, in resonant magnetic systems, the inductors are resonated using at least one capacitor. Furthermore, in resonant magnetic systems, the transmitter is self-resonant and the receiver is self-resonant. The range of power transfer in resonant magnetic systems is increased beyond that of magnetic induction systems, and alignment issues are corrected. While electromagnetic energy is generated in magnetic induction and resonant magnetic systems, the majority of power transfer occurs via magnetic fields. Little, if any, power is transferred via electric induction or resonant electrical induction.

[0006] In a capacitive system, the transmitter and receiver have capacitive electrodes. Power transfer occurs through the coupling of an electric field between the capacitive electrodes of the transmitter and receiver. Similar to a resonant magnetic system, a resonant electric system exists that uses at least one inductor to resonate the capacitive electrodes of the transmitter and receiver. The inductor may be a coil. In a resonant electric system, the transmitter is self-resonant and the receiver is self-resonant. A resonant electric system increases the range of power transfer compared to an electric induction system and corrects alignment issues. While electromagnetic energy is generated in electric induction and resonant electric systems, the majority of power transfer occurs through electric fields. Little, if any, power is transferred through magnetic induction or resonant magnetic induction.

[0007] While several wireless power transfer systems are known, improvements and / or alternatives are desirable. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent Application No. 17 / 018328 (U.S. Patent Application Publication No. 2021 / 0083634) [Patent Document 2] U.S. Patent No. 9,653,948 [Patent Document 3] U.S. Patent Application No. 17 / 899711 (U.S. Patent Application Publication No. 2022 / 0416582) [Patent Document 4] U.S. Provisional Application No. 62 / 899165 [Patent Document 5] U.S. Patent Application No. 17 / 193539 (U.S. Patent Application Publication No. 2021 / 0281122) [Patent Document 6] U.S. Patent No. 9,979,206 [Patent Document 7] U.S. Patent Application No. 17 / 083735 (U.S. Patent Application Publication No. 2021 / 0126494) Summary of the Invention [Problem to be solved by the invention]

[0009] This background merely serves to set a context that enables those skilled in the art to better understand the following description. Thus, nothing in the above statement should necessarily be construed as an admission that the statement is part of the state of the art or is common general knowledge. One or more aspects / embodiments of the present disclosure may or may not address one or more of the background problems. [Means for solving the problem]

[0010] According to one aspect of the present disclosure, a method, a controller, a transmitter, and a wireless power transmission system for / of wireless power transmission through a medium are provided.

[0011] A medium may be between the transmitter and receiver of a wireless power system. The medium may be, at least in part, in the form of an air gap, or may be, at least in part, a physical medium such as glass, wood, concrete, or other building materials. The wireless power transfer system may be tailored to a particular medium, e.g., the thickness of the medium or the material properties of the medium. Changing the properties of the medium, e.g., the thickness, or changing the medium altogether, e.g., introducing other materials into the space between the transmitter and receiver, may result in less-than-optimal wireless power transfer between the transmitter and receiver. Tuning the system may not be optimal for the new, changed medium or new medium properties or parameters. As a result, power transfer from the transmitter to the receiver may be less-than-optimal, e.g., the average power transfer efficiency may be reduced. Adjusting the wireless power transfer to account for changes to the medium may correspondingly improve the average power transfer efficiency. The described methods, controllers, transmitters, and wireless power transfer systems may result in such improved average power transfer efficiency.

[0012] According to another aspect of the present disclosure, there is provided a method of wireless power transmission through a medium, the method comprising: controlling an input voltage of an inverter of a transmitter of the wireless power transfer system based on the detected parameter; Includes.

[0013] The transmitter and receiver may be separated by a medium. The transmitter of the wireless power transfer system may generate a field, e.g., an electric field and / or a magnetic field, at least partially within the medium. The field may be for transmitting power wirelessly to the receiver.

[0014] The major surfaces of the transmitter and receiver elements, respectively, may be aligned, the major surfaces may form parallel planes, and the major surfaces may be adjacent to the medium.

[0015] The transmitter and / or receiver may be affixed to opposing surfaces that define the medium. For example, the transmitter and / or receiver may be affixed to opposing exterior and interior surfaces of an architectural structure formed of wood, concrete, glass, etc. The transmitter and / or receiver may be affixed to both sides of a window, e.g., a glass window.

[0016] The control may be performed by a controller, which may include a microcontroller (MCU), which may form part of the transmitter or may be in close proximity to the transmitter.

[0017] The method is: generating a field by a transmitting resonator of the transmitter, the transmitting resonator being electrically connected to the inverter, for transmitting power wirelessly through the medium to a receiver of the wireless power transfer system; It may further include:

[0018] The generated field may be based on the input voltage. The strength of the generated field may be based on the input voltage.

[0019] The method is: Detecting parameters in a transmitter and / or receiver of a wireless power transfer system - Patent Application 20070122997 The parameter may further include: the parameter may be detected at a transmitter resonator and / or a receiver resonator of the transmitter and receiver, respectively; the parameter may be detected at a rectifier element of the receiver; the parameter may be detected at an output of the rectifier element; the rectifier element may include a diode rectifier.

[0020] The parameter may include a rectified voltage at a receiver of the wireless power transfer system. The rectified voltage may be at a receiver resonator of the receiver. The rectified voltage may be a rectified power signal extracted from a field generated by the transmitter. The parameter may include a ratio of the detected rectified voltage to a voltage input to the receiver, i.e., the input voltage. The parameter may include a change in the detected rectified voltage at the receiver of the wireless power transfer system over time.

[0021] The step of controlling the input voltage of the inverter includes: controlling the output voltage of a converter electrically connected to the inverter; The converter may be a DC / DC converter of the transmitter. The DC / DC converter may be electrically connected to the inverter such that an output voltage of the DC / DC converter is an input voltage of the inverter. The DC / DC converter may be for adjusting a voltage level of a power signal input to the inverter. The DC / DC converter may receive a power signal from a power source and convert the power signal to an appropriate voltage for the inverter.

[0022] The transmitter may further include a transmitter resonator electrically connected to the inverter. The transmitter resonator may generate a field, such as a magnetic field or an electric field, for transmitting power to a receiver of the wireless power system. The transmitter resonator may include a transmitter element. The transmitter element may include a capacitive electrode and / or an inductor or inductive coil.

[0023] The method is: communicating the detected parameters to a transmitter. It may further include:

[0024] The communicating step includes: communicating the detected parameters from the receiver to the transmitter. may include:

[0025] The communicating step may include communicating via Bluetooth, Wi-Fi, 5G, or other suitable communication protocol. modifying the operation of a rectifier of a receiver of a wireless power transfer system; detecting a parameter change in a transmitter of a wireless power transfer system based on a change in operation of a rectifier; determining data communicated from the receiver to the transmitter based on the parameter change; The data may include the detected parameters.

[0026] The rectifier may include a diode rectifier. The diode rectifier may include a full-bridge diode rectifier.

[0027] The step of modifying the operation of the rectifier comprises: Switching the operation of electrical components at the input or output of the rectifier. The electrical component may include a resistor or a capacitor. Switching the operation may include switching the operation of a resistor at the output of a rectifier, e.g., a diode rectifier, and / or switching the operation of a capacitor at the input of the rectifier, e.g., a diode rectifier. Switching the operation may include controlling a switching element electrically connected to the electrical component. The switching element may include a FET, e.g., a MOSFET. A controller of the receiver may switch the operation of the electrical component.

[0028] The communicating step includes: modifying the operation of a synchronous rectifier of a receiver of a wireless power transfer system; detecting a parameter change in a transmitter of a wireless power transfer system based on a change in operation of a synchronous rectifier; determining data communicated from the receiver to the transmitter based on the parameter change; The data may include the detected parameters.

[0029] Altering the operation of the synchronous rectifier may result in a detectable parameter change in the transmitter. Detection of this change in the parameter in the transmitter may be used to determine data communicated from the receiver to the transmitter. Communicating data from the receiver to the transmitter based on altering the operation of the synchronous rectifier may be more power efficient and allow for greater throughput than conventional communication methods.

[0030] The step of modifying the operation of the synchronous rectifier comprises: toggling the synchronous rectifier between synchronous and asynchronous operation. may include:

[0031] The step of modifying the operation of the synchronous rectifier comprises: Selectively enabling and disabling a synchronous rectifier may include:

[0032] Selectively enabling and disabling the synchronous rectifier may include enabling and disabling synchronous operation of the synchronous rectifier. Changing the operation of the synchronous rectifier may include toggling synchronous operation. The time between selectively enabling / disabling or toggling may be varied to communicate data from the receiver to the transmitter.

[0033] Selectively enabling and disabling the synchronous rectifier may include selectively enabling and disabling a portion of the synchronous rectifier. Further, selectively enabling and disabling the synchronous rectifier may include enabling and / or disabling one side of the synchronous rectifier in a push-pull configuration.

[0034] A synchronous rectifier may include a two-phase system or may have a push-pull configuration: one side (or phase) of the synchronous rectifier may be synchronous, while the other side may be asynchronous.

[0035] Selectively enabling and disabling the synchronous rectifier may include selectively enabling and disabling one side (or phase) of the synchronous rectifier.

[0036] The synchronous rectifier may include at least one field effect transistor (FET).

[0037] The synchronous rectifier may comprise at least one of the following: a rectifier element for rectifying the power signal to DC; Trigger circuit, A gate driver electrically connected to the trigger circuit and the rectifier element.

[0038] The gate driver may be for controlling operation of the rectifier element according to the trigger signal output by the trigger circuit, and may output a gate drive voltage or gate signal in phase with an input voltage received at the rectifier element.

[0039] The trigger circuit may ensure proper timing of the gate drive voltages or gate signals output by the gate drivers.

[0040] The rectifier element may include an amplifier. The rectifier element may include a FET. The rectifier element may include a load-independent class E rectifier. The class E rectifier design may be adapted to convert an input radio frequency (RF) power signal to DC. The operating or switching frequency of the rectifier element may be, for example, 13.56 MHz and 27.12 MHz.

[0041] The gate driver may output a gate drive voltage or gate signal to control the operation of the rectifier element. In particular, the gate signal may control the operation of the amplifier by controlling the operation of the FET.

[0042] The trigger circuit is A sampling circuit for sampling the input signal may also be provided.

[0043] The sampling circuit may be a voltage divider.

[0044] The trigger circuit is a delay line for delaying the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element; may also be provided.

[0045] The trigger circuit is a comparator for generating a clock signal by comparing the delayed signal output by the delay line with a DC voltage level; may also be provided.

[0046] The trigger circuit is an RC delay circuit for delaying the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element; may also be provided.

[0047] The RC delay circuit may comprise at least one resistor electrically connected to at least one capacitor.

[0048] The trigger circuit is A comparator for generating a clock signal by comparing the delayed signal output by the RC delay circuit with a DC voltage level may also be provided.

[0049] The synchronous rectifier may further include an auxiliary DC / DC converter for supplying power to at least one of the trigger circuit and the gate driver. In other words, the synchronous rectifier may include a power supply for supplying power to at least one of the trigger circuit and the gate driver. The power supply may be powered by power received at the receiver, for example, power received from the transmitter via wireless power transfer.

[0050] The auxiliary DC / DC converter may be electrically connected to a low-dropout (LDO) regulator.

[0051] The step of modifying the operation of the synchronous rectifier comprises: Controlling operation of at least one of the trigger circuit, the gate driver, and the auxiliary DC / DC converter. Modifying the operation of the synchronous rectifier may include controlling the operation of all of the trigger circuit, the gate driver, and the auxiliary DC / DC converter.

[0052] The step of controlling operation of the trigger circuit includes: controlling the operation of the comparator of the trigger circuit Controlling operation of the comparator may include selectively enabling and disabling the comparator. The comparator may include a comparator circuit. The comparator may include an enable pin. Controlling operation of the trigger circuit may include selectively enabling the comparator via the enable pin.

[0053] The step of controlling the operation of the auxiliary DC / DC converter includes: Selectively enabling and disabling operation of an auxiliary DC / DC converter to selectively power the trigger circuit and the gate driver. The step of selectively enabling / disabling the auxiliary DC / DC converter may include controlling power supplied to the auxiliary DC / DC converter. The auxiliary DC / DC converter may include an enable pin. The step of selectively enabling the auxiliary DC / DC converter may include selectively enabling the auxiliary DC / DC converter via the enable pin.

[0054] The step of detecting a parameter change includes: Detecting a voltage or current waveform at the transmitter The voltage or current waveform may be detected at some node of the transmitter. The voltage waveform may be detected at an output stage of the transmitter. The current waveform may be detected at the input of an inverter of the transmitter.

[0055] The step of determining the communicated data comprises: processing the detected voltage or current waveform to determine the communicated data; may include:

[0056] The step of processing the detected voltage or current waveform includes: filtering the voltage or current waveform; generating a logic level based on the filtered voltage or current waveform; decoding the data based on the generated logic levels; may include:

[0057] Logic levels may reflect variations in voltage or current waveforms. For example, a change from a high voltage to a low voltage may represent a data transition from 1 to 0, and a change from a low voltage to a high voltage may represent a data transition from 0 to 1.

[0058] The step of decrypting the data includes: determining a time interval between logic levels; decoding the data based on the time interval; Includes.

[0059] The method is: monitoring the parameter over a period of time It may further include:

[0060] The step of controlling the input voltage of the inverter includes: controlling the input voltage of the inverter based on changes in the monitored parameter over a period of time. may include:

[0061] The medium is Building structures, building materials such as wood and concrete, walls, doors, air, plastics, water, polymers, and windows The window may be made of glass. The transmitter and receiver may be disposed on opposite sides of the medium. The medium may separate the transmitter and receiver such that the medium defines a volume between the transmitter and receiver.

[0062] According to another aspect, a method of wireless power transfer through a medium is provided, the method including the steps of supplying power via an inverter to a transmitter resonator of a transmitter of a wireless power transfer system at an input voltage via the inverter to generate a field for wirelessly transferring power through the medium to a receiver of the wireless power transfer system; optimizing the input voltage of the inverter based on the detected parameters; may include:

[0063] The field may include a magnetic field and / or an electric field.

[0064] According to another aspect, a method for optimizing power transfer from a transmitter to a receiver in a wireless power transfer system over a medium is provided, the method comprising: optimizing an input voltage of an inverter of a transmitter of the wireless power transfer system based on the detected parameters; may include:

[0065] The step of optimizing the input voltage may optimize an average power transfer efficiency between a transmitter and a receiver of the wireless power transfer system.

[0066] Optimizing the input voltage may include adjusting the input voltage from a first voltage level to a second voltage level based on the detected parameter.

[0067] Adjusting the input voltage may include sequentially adjusting the input voltage between a plurality of voltage levels.

[0068] The way to optimize it is Detecting parameters in a transmitter and / or receiver of a wireless power transfer system - Patent Application 20070122997 The parameter may further include: the parameter may be detected at a transmitter resonator and / or a receiver resonator of the transmitter and receiver, respectively; the parameter may be detected at a rectifier element of the receiver; the parameter may be detected at an output of the rectifier element; the rectifier element may include a diode rectifier.

[0069] The parameters may include a rectified voltage at a receiver of the wireless power transfer system, which may be a rectified power signal extracted from a field generated by a transmitter.

[0070] The method is: communicating the rectified voltage from the receiver to the transmitter; It may further include:

[0071] The communicating step includes: communicating the detected parameters from the receiver to the transmitter. may include:

[0072] The communicating step may include communicating via Bluetooth, Wi-Fi, 5G, or other suitable communication protocol. modifying the operation of a rectifier of a receiver of a wireless power transfer system; detecting a parameter change in a transmitter of a wireless power transfer system based on a change in operation of a rectifier; determining data communicated from the receiver to the transmitter based on the parameter change; The data may include the detected parameters.

[0073] The rectifier may include a diode rectifier. The diode rectifier may include a full-bridge diode rectifier.

[0074] The step of modifying the operation of the rectifier comprises: Switching the operation of electrical components at the input or output of the rectifier. The electrical component may include a resistor or a capacitor. Switching the operation may include switching the operation of a resistor at the output of a rectifier, e.g., a diode rectifier, and / or switching the operation of a capacitor at the input of the rectifier, e.g., a diode rectifier. Switching the operation may include controlling a switching element electrically connected to the electrical component. The switching element may include a FET, e.g., a MOSFET. A controller of the receiver may switch the operation of the electrical component.

[0075] The communicating step includes: modifying the operation of a synchronous rectifier of a receiver of a wireless power transfer system; detecting a parameter change in a transmitter of a wireless power transfer system based on a change in operation of a synchronous rectifier; determining data communicated from the receiver to the transmitter based on the parameter change; The data may include the detected parameters.

[0076] The wireless power transfer system described may be a radio frequency wireless power system as described in applicant's U.S. provisional patent application Ser. No. 17 / 018328, a resonant capacitively coupled wireless power transfer system as described in applicant's own U.S. Patent No. 9,653,948 B2, or a bidirectional wireless power transfer system as described in applicant's own U.S. patent application Ser. No. 17 / 899,711, the relevant portions of which are incorporated herein.

[0077] Altering the operation of the synchronous rectifier may result in a detectable parameter change in the transmitter. Detection of this change in the parameter in the transmitter may be used to determine data communicated from the receiver to the transmitter. Communicating data from the receiver to the transmitter based on altering the operation of the synchronous rectifier may be more power efficient and allow for greater throughput than conventional communication methods.

[0078] The step of modifying the operation of the synchronous rectifier comprises: switching the synchronous rectifier between synchronous and asynchronous operation. may include:

[0079] The step of modifying the operation of the synchronous rectifier comprises: Selectively enabling and disabling a synchronous rectifier may include:

[0080] Selectively enabling and disabling the synchronous rectifier may include enabling and disabling synchronous operation of the synchronous rectifier. Changing the operation of the synchronous rectifier may include toggling the synchronous operation. The time between the selectively enabling / disabling or toggling may be varied to communicate data from the receiver to the transmitter.

[0081] Selectively enabling and disabling the synchronous rectifier may include selectively enabling and disabling a portion of the synchronous rectifier. Further, selectively enabling and disabling the synchronous rectifier may include enabling and / or disabling one side of the synchronous rectifier in a push-pull configuration.

[0082] A synchronous rectifier may include a two-phase system or may have a push-pull configuration: one side (or phase) of the synchronous rectifier may be synchronous, while the other side may be asynchronous.

[0083] Selectively enabling and disabling the synchronous rectifier may include selectively enabling and disabling one side (or phase) of the synchronous rectifier.

[0084] The synchronous rectifier may include at least one field effect transistor (FET).

[0085] The synchronous rectifier may comprise at least one of the following: a rectifier element for rectifying the power signal to DC; Trigger circuit, A gate driver electrically connected to the trigger circuit and the rectifier element.

[0086] The gate driver may be for controlling operation of the rectifier element according to the trigger signal output by the trigger circuit, and may output a gate drive voltage or gate signal in phase with an input voltage received at the rectifier element.

[0087] The trigger circuit may ensure proper timing of the gate drive voltages or gate signals output by the gate drivers.

[0088] The rectifier element may include an amplifier. The rectifier element may include a FET. The rectifier element may include a load-independent class E rectifier. The class E rectifier design may be adapted to convert an input radio frequency (RF) power signal to DC. The operating or switching frequency of the rectifier element may be, for example, 13.56 MHz and 27.12 MHz.

[0089] The gate driver may output a gate drive voltage or gate signal to control the operation of the rectifier element. In particular, the gate signal may control the operation of the FET, thereby controlling the operation of the amplifier.

[0090] The trigger circuit is A sampling circuit for sampling the input signal may also be provided.

[0091] The sampling circuit may be a voltage divider.

[0092] The trigger circuit is a delay line for delaying the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element; may also be provided.

[0093] The trigger circuit is a comparator for generating a clock signal by comparing the delayed signal output by the delay line with a DC voltage level; may also be provided.

[0094] The trigger circuit is an RC delay circuit for delaying the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element; may also be provided.

[0095] The RC delay circuit may comprise at least one resistor electrically connected to at least one capacitor.

[0096] The trigger circuit is A comparator for generating a clock signal by comparing the delayed signal output by the RC delay circuit with a DC voltage level may also be provided.

[0097] The synchronous rectifier may further include an auxiliary DC / DC converter for supplying power to at least one of the trigger circuit and the gate driver. In other words, the synchronous rectifier may include a power supply for supplying power to at least one of the trigger circuit and the gate driver. The power supply may be powered by power received at the receiver, for example, power received from the transmitter via wireless power transfer.

[0098] The auxiliary DC / DC converter may be electrically connected to a low dropout (LDO) regulator.

[0099] The step of modifying the operation of the synchronous rectifier comprises: Controlling operation of at least one of the trigger circuit, the gate driver, and the auxiliary DC / DC converter. Modifying the operation of the synchronous rectifier may include controlling the operation of all of the trigger circuit, the gate driver, and the auxiliary DC / DC converter.

[0100] The step of controlling operation of the trigger circuit includes: controlling the operation of the comparator of the trigger circuit Controlling operation of the comparator may include selectively enabling and disabling the comparator. The comparator may include a comparator circuit. The comparator may include an enable pin. Controlling operation of the trigger circuit may include selectively enabling the comparator via the enable pin.

[0101] The step of controlling the operation of the auxiliary DC / DC converter includes: Selectively enabling and disabling operation of an auxiliary DC / DC converter to selectively power the trigger circuit and the gate driver. The step of selectively enabling / disabling the auxiliary DC / DC converter may include controlling power supplied to the auxiliary DC / DC converter. The auxiliary DC / DC converter may include an enable pin. The step of selectively enabling the auxiliary DC / DC converter may include selectively enabling the auxiliary DC / DC converter via the enable pin.

[0102] The step of detecting a parameter change includes: Detecting a voltage or current waveform at the transmitter The voltage or current waveform may be detected at some node of the transmitter. The voltage waveform may be detected at an output stage of the transmitter. The current waveform may be detected at the input of an inverter of the transmitter.

[0103] The step of determining the communicated data comprises: processing the detected voltage or current waveform to determine the communicated data; may include:

[0104] The step of processing the detected voltage or current waveform includes: filtering the voltage or current waveform; generating a logic level based on the filtered voltage or current waveform; decoding the data based on the generated logic levels; may include:

[0105] Logic levels may reflect variations in voltage or current waveforms. For example, a change from a high voltage to a low voltage may represent a data transition from 1 to 0, and a change from a low voltage to a high voltage may represent a data transition from 0 to 1.

[0106] The step of decrypting the data includes: determining a time interval between logic levels; decoding the data based on the time interval; Includes.

[0107] According to yet another aspect, a method is provided for detecting a medium between a transmitter of a wireless power transfer system and a receiver of the wireless power transfer system, the receiver being for extracting power from a field generated by the transmitter.

[0108] This method is Detecting a parameter at a transmitter of a wireless power transfer system and / or a receiver of the wireless power transfer system; detecting a medium between the transmitter and the receiver based on the parameters; may include:

[0109] The medium is Building structures, building materials such as wood and concrete, walls, doors, air, plastics, water, polymers, and windows The window may be made of glass. The transmitter and receiver may be disposed on opposite sides of the medium. The medium may separate the transmitter and receiver such that the medium defines a volume between the transmitter and receiver.

[0110] The parameters may include a rectified voltage at a receiver of the wireless power transfer system, the rectified voltage may be at a receiver resonator of the receiver, or the rectified voltage may be a rectified power signal extracted from a field generated by a transmitter.

[0111] The parameter may include a reactance at a receiver of the wireless power transfer system. The reactance may be at a receiver resonator of the receiver. The parameter may include a phase of the impedance at the receiver. Specifically, the parameter may include a phase of the impedance at the receiver resonator or a receiver element of the receiver. The phase of the impedance may be a phase angle. The phase angle may be related to reactance in that a large phase angle, for example, a phase angle above a predetermined threshold, may indicate a large reactance. Similarly, a small phase angle, for example, a phase angle below a predetermined threshold, may indicate a small reactance.

[0112] The parameters may include power received at the receiver, which may include power to a load electrically connected (possibly indirectly) to the receiver element or power output by a rectifying element at the receiver.

[0113] The parameters may include temperature data, e.g., the temperature of a receiver element, a receiver resonator, or a rectifier element. The method may further include controlling an output voltage of the transmitter converter, e.g., a DC / DC converter, based on the detected temperature data. The controlling step may include lowering or raising the output voltage based on the temperature data. For example, if the temperature data indicates that the temperature of some receiver element, e.g., a rectifier element, exceeds a threshold, the output voltage may be lowered. This may reduce the temperature in the receiver element.

[0114] The parameters may include the magnitude of the impedance in the receiver resonator or in the receiver element of the receiver.

[0115] Those skilled in the art will appreciate that multiple parameters may be detected. For example, any combination of the above parameters (reactance, rectified voltage, phase, and impedance magnitude) may be detected. Detection of the medium may be based on one or more of the detected parameters.

[0116] Detecting the medium may include detecting the presence of metal between the transmitter and the receiver.

[0117] Detecting the medium may include detecting the medium between the transmitter and the receiver based on a parameter reaching a threshold level, where the threshold level may be indicative of a particular medium, for example, a threshold between known ranges may indicate the presence of metal between the transmitter and the receiver.

[0118] According to another aspect, a controller configured to control at least one of a transmitter inverter, a transmitter converter, a transmitter and a receiver of a wireless power transfer system to perform any of the described methods is provided.

[0119] According to another aspect, a controller is provided for wirelessly transferring power through a medium by any of the described methods.

[0120] The controller described may include an MCU.

[0121] The converter may include a DC / DC converter.

[0122] The described controller may also be for communicating signals between a receiver of a wireless power transfer system and a transmitter of the wireless power transfer system, the receiver comprising a synchronous rectifier.

[0123] The controller may be adapted to modify the operation of the synchronous rectifier to vary a detectable parameter in the transmitter.

[0124] The controller may be adapted to switch the synchronous rectifier between synchronous and asynchronous operation.

[0125] The controller may be adapted to selectively enable and disable the synchronous rectifier.

[0126] Selectively enabling and disabling the synchronous rectifier may include enabling and disabling synchronous operation of the synchronous rectifier. Changing the operation of the synchronous rectifier may include toggling synchronous operation. The time between selectively enabling / disabling or toggling may be varied to communicate data from the receiver to the transmitter.

[0127] The controller may be electrically connected to the synchronous rectifier.

[0128] The controller synchronous rectifier trigger circuit, a gate driver for the synchronous rectifier, the gate driver being electrically connected to a trigger circuit and a rectifier element of the synchronous rectifier; may be electrically connected to at least one of the

[0129] The controller may be adapted to control operation of a comparator of the trigger circuit. Controlling operation of the comparator may include selectively enabling a power supply to the comparator. The comparator may include a comparator circuit.

[0130] The controller An auxiliary DC / DC converter for a synchronous rectifier, the auxiliary DC / DC converter being for powering at least one of a trigger circuit and a gate driver. may be electrically connected to

[0131] The controller may be adapted to selectively enable and disable operation of the auxiliary DC / DC converter to selectively power at least one of the trigger circuit and the gate driver. Selectively enabling / disabling the auxiliary DC / DC converter may include controlling power supplied to the auxiliary DC / DC converter.

[0132] The controller may further include a power supply for supplying power to the controller. The power supply may supply power to at least one of the trigger circuit and the gate driver. The power supply may be powered by power received at the receiver, for example, power received from the transmitter via wireless power transfer.

[0133] The power supply may include an auxiliary DC / DC converter.

[0134] The controller may be powered by an LDO regulator.

[0135] According to another aspect, a method of wireless power transmission through a medium is provided. The medium may be between a transmitter and a receiver of a wireless power transmission system. The transmitter may generate a field that is at least partially within the medium. The receiver may extract power from the generated field. The transmitter and receiver may be on opposite sides of the medium, such that the transmitter and receiver are separated by the medium.

[0136] This method is detecting a parameter in a receiver of a wireless power transfer system; communicating the sensed parameter to a transmitter of a wireless power transfer system; controlling an input voltage of an inverter of the transmitter based on the sensed parameter; generating a field for wirelessly transmitting power through a medium to a receiver of a wireless power transfer system; may include:

[0137] The detecting step may include detecting with a voltage detector in a receiver of the wireless power transfer system.

[0138] The parameters may include a rectified voltage at the receiver. The parameters may include a rectified voltage at the output of a rectifier element of the receiver. The rectifier element may include an amplifier. The rectifier element may include a field effect transistor (FET). The rectifier element may include a load-independent class E rectifier. The class E rectifier design may be adapted to convert an input radio frequency (RF) power signal to DC. The operating or switching frequency of the rectifier element may be, for example, 13.56 MHz and 27.12 MHz.

[0139] The communicating step may include communicating through a controller of the receiver, which may include one or more MCUs.

[0140] The controlling step may include controlling by a controller of the transmitter. The controller may include one or more MCUs. The controlling step may include controlling an output voltage of a converter electrically connected to the inverter. The converter may include a DC / DC converter. The DC / DC converter may be for converting a received DC voltage signal to a desired voltage level. The received DC voltage may be from a power supply of the transmitter.

[0141] The generating step may include generating with a transmit resonator of a transmitter. The transmit resonator may be electrically connected to the inverter. The strength of the generated field may be based on the converter output voltage and / or the inverter input voltage.

[0142] According to another aspect, a non-transitory computer-readable medium is provided that includes computer-executable code for execution on a processor to perform any of the described methods.

[0143] According to another aspect, a transmitter of a wireless power transfer system is provided, the transmitter for wirelessly transmitting power through a medium to a receiver of the wireless power transfer system.

[0144] The transmitter is a transmitter resonator for wirelessly transmitting power through a medium to a receiver of a wireless power transfer system; an inverter electrically connected to the transmit resonator; a controller for controlling the input voltage of the inverter based on the detected parameters; may also be provided.

[0145] The controller described may include an MCU.

[0146] The transmitter is Sensors for detecting parameters in the transmitter and / or receiver may further comprise:

[0147] The parameters may include a rectified voltage at a receiver of the wireless power transfer system, the rectified voltage may be at a receiver resonator of the receiver, or the rectified voltage may be a rectified power signal extracted from a field generated by a transmitter.

[0148] The transmitter is COMMUNICATION MODULE FOR RECEIVING PARAMETERS FROM A RECEIVER OF A WIRELESS POWER TRANSMISSION SYSTEM - Patent application may further comprise:

[0149] The communication module may include a controller for detecting a parameter change in the transmitter based on a change to the operation of the receiver's synchronous rectifier. The communication module may receive the parameter via a communication protocol, including Bluetooth, Wi-Fi, 5G, or other suitable communication protocol.

[0150] The controller may be further adapted to determine data communicated from the receiver to the transmitter based on the parameter change.

[0151] The controller Detector for detecting voltage and / or current waveforms in a transmitter may further comprise:

[0152] The detector is A demodulator adapted to demodulate voltage and / or current waveforms at a transmitter may further comprise:

[0153] The detector is a filter adapted to filter the demodulated voltage and / or current; may also be provided.

[0154] The detector is generating a logic level based on the filtered voltage and / or current; Decoding data based on the generated logic levels; The method may be adapted to:

[0155] The detector is determining a time interval between logic levels; Decoding the data based on the time interval; The method may be adapted to:

[0156] The controller may further comprise a power supply for providing power to the controller.

[0157] The power supply may include an auxiliary DC / DC converter.

[0158] The controller may be powered by an LDO regulator.

[0159] The controller A scaling unit for reducing the amplitude of the detected voltage or current waveform Reducing the amplitude of the waveform may simplify processing of the waveform.

[0160] The controller A peak detector for detecting peaks in the detected voltage or current waveform may further comprise:

[0161] The controller signal conditioner may further comprise:

[0162] The signal conditioner may be adapted to amplify the detected voltage or current waveform.

[0163] The signal conditioner may be adapted to compare the detected voltage or current waveform with a reference level, e.g., a reference voltage or current level, and to output a logic level signal, e.g., a 0 or a 1, based on the comparison.

[0164] The signal conditioner may comprise a comparator, which may be adapted to perform the comparisons described.

[0165] The controller an encoder for receiving data and encoding the data into a time sequence Therefore, data transmitted from the receiver to the transmitter may be encoded into a time sequence of synchronous and asynchronous operations of the synchronous rectifier. The data may be binary data.

[0166] The synchronous rectifier may be switched between synchronous and asynchronous operation based on a time sequence encoded by the encoder. Switching the synchronous rectifier according to the time sequence may result in searchable parameter changes in the transmitter, which may be demodulated or decoded into data, thereby communicating the data from the receiver to the transmitter.

[0167] According to another aspect, a wireless power transfer system is provided, the system comprising: a transmitter including a transmitter resonator for wirelessly transmitting power through a medium to a receiver of a wireless power transfer system, and an inverter electrically connected to the transmitter resonator; a receiver having a receiving resonator for wirelessly extracting power from the transmitter by electric and / or magnetic field coupling; a controller for controlling the input voltage of the inverter based on the detected parameters; Equipped with.

[0168] This system is Sensors for detecting parameters in the transmitter and / or receiver may further comprise:

[0169] The parameters may include a rectified voltage at a receiver of the wireless power transfer system, the rectified voltage may be at a receiver resonator of the receiver, or the rectified voltage may be a rectified power signal extracted from a field generated by a transmitter.

[0170] The receiver is A communication module for communicating parameters from the receiver to the transmitter may further comprise:

[0171] The communication module may include a controller. The controller may include an MCU. The controller may be adapted to modify operation of the synchronous rectifier to vary a parameter detectable at the transmitter. The communication module may communicate the parameter via a communication protocol, including Bluetooth, Wi-Fi, 5G, or other suitable communication protocol.

[0172] The controller may be adapted to switch the synchronous rectifier between synchronous and asynchronous operation.

[0173] The controller may be adapted to selectively enable and disable the synchronous rectifier.

[0174] Selectively enabling and disabling the synchronous rectifier may include enabling and disabling synchronous operation of the synchronous rectifier. Changing the operation of the synchronous rectifier may include toggling operation of the synchronous operation. The time between selectively enabling / disabling or toggling operation may be varied to communicate data from the receiver to the transmitter.

[0175] The controller may be electrically connected to the synchronous rectifier.

[0176] The controller synchronous rectifier trigger circuit, a gate driver for the synchronous rectifier, the gate driver being electrically connected to a trigger circuit and a rectifier element of the synchronous rectifier; may be electrically connected to at least one of the

[0177] The controller may be adapted to control operation of a comparator of the trigger circuit. Controlling operation of the comparator may include selectively enabling a power supply to the comparator. The comparator may include a comparator circuit.

[0178] The controller An auxiliary DC / DC converter for a synchronous rectifier, the auxiliary DC / DC converter being for powering at least one of a trigger circuit and a gate driver. may be electrically connected to

[0179] The controller may be adapted to selectively enable and disable operation of the auxiliary DC / DC converter to selectively power at least one of the trigger circuit and the gate driver. Selectively enabling / disabling the auxiliary DC / DC converter may include controlling power supplied to the auxiliary DC / DC converter.

[0180] The controller may further include a power supply for supplying power to the controller. The power supply may supply power to at least one of the trigger circuit and the gate driver. The power supply may be powered by power received at the receiver, for example, power received from the transmitter via wireless power transfer.

[0181] The power supply may include an auxiliary DC / DC converter.

[0182] The controller may be powered by an LDO regulator.

[0183] The transmitter is A communication module for receiving parameters from the receiver may further comprise:

[0184] The communication module may further include a controller. The controller may include a microcontroller (MCU). The controller may be adapted to detect a parameter change in the transmitter based on a change to the operation of the synchronous rectifier of the receiver. The communication module may receive the parameter via a communication protocol including Bluetooth, Wi-Fi, 5G, or other suitable communication protocol.

[0185] The controller may be further adapted to determine data communicated from the receiver to the transmitter based on the parameter change.

[0186] The controller Detector for detecting voltage and / or current waveforms in a transmitter may further comprise:

[0187] The detector is A demodulator adapted to demodulate voltage and / or current waveforms at a transmitter may further comprise:

[0188] The detector is a filter adapted to filter the demodulated voltage and / or current; may also be provided.

[0189] The detector is generating a logic level based on the filtered voltage and / or current; Decoding data based on the generated logic levels; The method may be adapted to:

[0190] The detector is determining a time interval between logic levels; Decoding the data based on the time interval; The method may be adapted to:

[0191] The controller may further comprise a power supply for providing power to the controller.

[0192] The power supply may include an auxiliary DC / DC converter.

[0193] The controller may be powered by an LDO regulator.

[0194] The controller A scaling unit for reducing the amplitude of the detected voltage or current waveform Reducing the amplitude of the waveform may simplify processing of the waveform.

[0195] The controller A peak detector for detecting peaks in the detected voltage or current waveform may further comprise:

[0196] The controller signal conditioner may further comprise:

[0197] The signal conditioner may be adapted to amplify the detected voltage or current waveform.

[0198] The signal conditioner may be adapted to compare the detected voltage or current waveform with a reference level, e.g., a reference voltage or current level, and to output a logic level signal, e.g., a 0 or a 1, based on the comparison.

[0199] The signal conditioner may comprise a comparator, which may be adapted to perform the comparisons described.

[0200] The controller an encoder for receiving data and encoding the data into a time sequence Therefore, data transmitted from the receiver to the transmitter may be encoded into a time sequence of synchronous and asynchronous operations of the synchronous rectifier. The data may be binary data.

[0201] The transmitter is A converter electrically connected to an inverter The converter may further include a DC / DC converter.

[0202] The controller may be configured to control the output voltage of the converter based on the sensed parameter. The output voltage of the converter may define the input voltage of the inverter.

[0203] According to another aspect, a computer-readable medium is provided that includes instructions that, when executed by a processor, perform any of the described methods.

[0204] The computer-readable medium may be non-transitory. The computer-readable medium may include storage media other than propagating signals. The computer-readable medium may include any suitable memory or storage device, such as random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or flash memory.

[0205] The processor may have a single core or multiple cores constructed from a variety of materials such as silicon, polysilicon, high-K dielectrics, copper, etc.

[0206] According to another aspect, there is provided a computer program comprising instructions which, when executed by a processor, perform any of the methods described.

[0207] The present invention includes one or more corresponding aspects, embodiments, or features, whether specifically set forth (including claimed) in that combination or separately, separately or in various combinations. As will be appreciated, features associated with particular described embodiments relating to systems may equally be appropriate as features of embodiments particularly relating to methods of operation or use, and vice versa.

[0208] The above summary is intended to be illustrative only and non-limiting.

[0209] These and other aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying figures. [Brief explanation of the drawings]

[0210] [Figure 1] FIG. 1 is a block diagram of a wireless power transmission system. [Figure 2] FIG. 2 is another block diagram of a wireless power transmission system. [Figure 3] 3 is a block diagram of a transmitter and a receiver of the wireless power transfer system of FIG. 2 separated by a medium. [Figure 4] FIG. 3 is a block diagram of a receiver of the wireless power transmission system of FIG. 2. [Figure 5] FIG. 3 is a block diagram of a portion of the receiver circuitry of FIG. 2. [Figure 6] FIG. 3 is a schematic diagram of a portion of the receiver circuit of FIG. 2. [Figure 7] FIG. 1 is a block diagram of a receiver of a wireless power transfer system according to one aspect of the present disclosure. [Figure 8] FIG. 1 is a block diagram of a receiver of a wireless power transfer system according to one aspect of the present disclosure. [Figure 9] FIG. 9 is a schematic diagram of a portion of the receiver of FIG. 8. [Figure 10] 9 is a schematic diagram of a further portion of the receiver of FIG. 8. [Figure 11] FIG. 1 is a block diagram of a transmitter of a wireless power transfer system according to one aspect of the present disclosure. [Figure 12] FIG. 12 is a schematic diagram of a portion of the transmitter of FIG. [Figure 13] FIG. 12 is a block diagram of a detector of the transmitter of FIG. 11. [Figure 14] 1 is a flowchart of a method for wireless power transmission over a medium according to one aspect of the present disclosure. [Figure 15] 10 is a graph of voltage and current waveforms of a transmitter according to one aspect of the present disclosure. [Figure 16] 10 is a graph of voltage rise time for a transmitter according to one aspect of the present disclosure. [Figure 17]10 is a graph of voltage fall time for a transmitter according to one aspect of the present disclosure. [Figure 18] 10 is a graph of current rise time for a transmitter according to one aspect of the present disclosure. [Figure 19] 10 is a graph of current fall time for a transmitter according to one aspect of the present disclosure. [Figure 20] FIG. 1 is a schematic diagram of a portion of a transmitter according to one aspect of the present disclosure. [Figure 21] FIG. 21 is a block diagram of a current demodulator of the transmitter of FIG. 20. DETAILED DESCRIPTION OF THE INVENTION

[0211] The foregoing summary, as well as the following detailed description of certain embodiments, will be better understood when read in conjunction with the accompanying drawings. It will be appreciated that like reference numerals are used to refer to like elements throughout the description and the drawings. As used herein, an element or feature described in the singular and preceded by the words "a" or "an" should be understood as not necessarily excluding a plurality of elements or features. Furthermore, references to "one example" or "one embodiment" are not intended to be interpreted as excluding the existence of additional examples or embodiments that also incorporate the described elements or features of that example or embodiment. Furthermore, unless expressly stated otherwise, examples or embodiments that "comprise," "have," or "include" one or more elements or features having a particular property may further include additional elements or features that do not possess that particular property. It will also be appreciated that the terms "comprise," "have," and "include" mean "including but not limited to," and that "comprising," "having," and "including" have equivalent meanings.

[0212] As used herein, the term "and / or" may include any and all combinations of one or more of the associated listed elements or features.

[0213] When an element or feature is referred to as being "on," "attached to," "connected to," "coupled to," or "in contact with" another element or feature, it is understood that the element or feature may be directly on, attached to, connected to, coupled to, or in contact with the other element or feature, or that intervening elements may be present. In contrast, when an element or feature is referred to as being, for example, "directly on," "directly attached to," "directly connected to," "directly coupled to," or "directly in contact with" another element or feature, no intervening elements or features are present.

[0214] It will be appreciated that spatially relative terms such as "below," "lower," "belower," "above," "upper," "upper," "forward," "rearward," etc. may be used herein to facilitate the description of the relationship of elements or features to other elements or features, as illustrated in the figures. However, spatially relative terms may encompass different orientations during use or operation in addition to the orientations illustrated in the figures.

[0215] Reference herein to an "example" means that one or more features, structures, elements, components, properties, and / or operational steps described in connection with the example are included in at least one embodiment and / or implementation of the subject matter according to the present disclosure. Thus, the phrases "one example," "another example," and similar language throughout this disclosure may, but do not necessarily, refer to the same example. Furthermore, subject matter characterizing any one example may, but does not necessarily, include subject matter characterizing any other example.

[0216] References herein to "comprised of" essentially refer to an actual state of configuration that links an element or feature to the physical characteristics of the element or feature that precedes the phrase "comprised of."

[0217] Unless otherwise indicated, terms such as "first," "second," etc. are used herein merely as labels and do not impose any order, position, or hierarchical requirement on the items to which they refer. Furthermore, a reference to a "second" item does not require or preclude the presence of lower-numbered items (e.g., a "first" item) and / or higher-numbered items (e.g., a "third" item).

[0218] As used herein, the terms "approximately" and "about" refer to an amount close to the stated amount that still performs the desired function or achieves the desired result. For example, the terms "approximately" and "about" can refer to an amount that is within less than 10%, less than 5%, less than 1%, less than 0.1%, or less than 0.01% of the stated amount.

[0219] 1 , there is shown a wireless power transfer system generally identified by the reference numeral 100. The wireless power transfer system 100 includes a transmitter 110 including a power source 112 electrically connected to a transmitter element 116, and a receiver 120 including a receiver element 124 electrically connected to a load 128. Power is transferred from the power source 112 to the transmitter element 116. Power is then transferred from the transmitter element 116 to the receiver element 124 by resonant or non-resonant electric or magnetic field coupling. Power is then transferred from the receiver element 124 to the load 128. An exemplary wireless power transfer system 100 includes a high frequency inductive wireless power transfer system as described in Applicant's U.S. Provisional Application No. 62 / 899,165 or a resonant capacitively coupled wireless power transfer system as described in Applicant's U.S. Patent No. 9,653,948 (B2), relevant portions of which are incorporated herein.

[0220] In the wireless power transfer system 100, power is transferred from a transmitter element 116 to a receiver element 124. The exemplary wireless power transfer system 100 includes a high frequency inductive wireless power transfer system as described in U.S. Patent Application No. 17 / 018,328, relevant portions of which are incorporated herein.

[0221] 2, another embodiment of a wireless power transfer system is shown generally identified by the reference numeral 200. Wireless power transfer system 200 includes a power source 212, a DC / DC converter 214, circuitry 216, and a transmitter element 222. Power source 212 is electrically connected to DC / DC converter 214. DC / DC converter 214 is electrically connected to circuitry 216. Circuitry 216 is electrically connected to transmitter element 222.

[0222] The power supply 212 is for generating an input power signal for transmission of power. In this embodiment, the input power signal is a direct current (DC) power signal.

[0223] DC / DC converter 214 is for converting a received DC voltage signal to a desired voltage level. The received DC voltage may be from power supply 212. While system 200 is described as including DC / DC converter 214, one skilled in the art will appreciate that other configurations are possible. In another embodiment, a DC / DC converter is not present.

[0224] In the illustrated configuration, the circuit 216 includes an inverter and an output stage that matches the output impedance of the circuit 216 to the optimum impedance of the wireless link 230 between the transmitter and receiver. The output stage also filters high frequency harmonic content of the inverter.

[0225] The transmitter element 222 comprises one or more inductive elements, i.e., inductors. The inductive elements may include one or more coils. The coils may include booster coils or shielding coils as described in applicant's U.S. patent application Ser. No. 17 / 193,539, relevant portions of which are incorporated herein by reference.

[0226] In another configuration, transmitter element 222 includes one or more capacitive elements, e.g., capacitive electrodes. The capacitive electrodes may be laterally spaced, elongated electrodes, although one skilled in the art will appreciate that other configurations are possible, including, but not limited to, concentric electrodes, coplanar electrodes, circular electrodes, elliptical electrodes, disk electrodes, etc. Other suitable electrode configurations are described in applicant's U.S. Pat. No. 9,979,206 (B2), relevant portions of which are incorporated herein by reference. As one skilled in the art will appreciate, transmitter element 222 may comprise a combination of inductive and capacitive elements.

[0227] Power supply 212 provides a DC input power signal to DC / DC converter 214, which converts the signal to a desired voltage level. An inverter in circuit 216 receives the converted DC power signal and inverts the converted DC power signal to generate a magnetic field and / or an electric field in transmitter element 222 to transmit power via electric or magnetic field coupling. Specifically, transmitter element 222 generates a magnetic field / electric field to transmit power to a receiver via magnetic field / electric field coupling. Power supply 212, DC / DC converter 214, circuit 216, and transmitter element 222 may collectively form transmitter 210. As previously mentioned, DC / DC converter 214 may not be present in transmitter 210.

[0228] The wireless power transfer system 200 further includes a load 228, a DC / DC converter 226, a circuit 224, and a receiver element 229. The load 228 is electrically connected to the DC / DC converter 226. The DC / DC converter 226 is electrically connected to the circuit 224. The circuit 224 is electrically connected to the receiver element 229.

[0229] In the illustrated configuration, the load 228 is a DC load. The load 228 may be static or variable.

[0230] DC / DC converter 226 is for converting a received DC voltage signal to a desired voltage level. The received DC voltage may be from circuit 224. While system 200 includes DC / DC converter 226, one skilled in the art will appreciate that other configurations are possible. In another embodiment, DC / DC converter 226 is not present.

[0231] The circuit 224 includes an input stage and a rectifier, e.g., a diode rectifier or a synchronous rectifier. The input stage is configured to ensure an optimal impedance presented to the receiver element 229 at full power conditions of the wireless power transfer system 200. The input stage may also maintain the quasi-voltage source behavior of the receiver element 229 such that the output of the synchronous rectifier exhibits a stable DC voltage from no-load to full-load conditions.

[0232] The receiver element 229 comprises one or more inductive elements, i.e., inductors. The receiver element 229 may include one or more coils. The coils may include booster coils or shield coils as described in applicant's U.S. patent application Ser. No. 17 / 193,539, relevant portions of which are incorporated herein by reference.

[0233] In another configuration, transmitter element 222 includes one or more capacitive elements, e.g., capacitive electrodes. The capacitive electrodes may be laterally spaced, elongated electrodes, although one skilled in the art will appreciate that other configurations are possible, including, but not limited to, concentric electrodes, coplanar electrodes, circular electrodes, elliptical electrodes, disk electrodes, etc. Other suitable electrode configurations are described in applicant's U.S. Pat. No. 9,979,206 (B2), relevant portions of which are incorporated herein by reference. As one skilled in the art will appreciate, transmitter element 222 may include a combination of inductive and capacitive elements.

[0234] The transmitter element 222 and receiver element 229 of the system 200 form a wireless link 230. The elements 222, 229 are separated by a wireless gap. The wireless gap may be formed by the atmosphere, i.e., air, or by a physical medium, e.g., a wall, glass, liquid, wood, insulator, etc. Power is transferred from one element to the other across the wireless link 230 by resonant or non-resonant magnetic and / or electric field coupling, i.e., electric or magnetic induction.

[0235] During operation, the receiver element 229 extracts power from the magnetic and / or electric fields generated by the transmitter element 222. The circuit 224 functions as a rectifier, e.g., a diode rectifier or a synchronous rectifier, to rectify the received power signal. The DC / DC converter 226 converts the rectified power signal to a desired power level to be received by the load 228. In this manner, the receiver element 229 extracts power transmitted by the transmitter element 222 (transmitter 210) so that the power is transferred to the load 228 by magnetic / electric field coupling. The load 228, the DC / DC converter 226, the circuit 224, and the receiver element 229 may collectively form the receiver 220. As previously mentioned, the DC / DC converter 226 may not be present in the receiver 220.

[0236] 3, there is shown a transmitter 210 and a receiver 220 of a system 200. In the illustrated configuration, the transmitter 210 and the receiver 220 are separated by a medium 232. The medium 232 is between the transmitter 210 and the receiver 220. The medium 232 may define a separation distance between the transmitter element 222 and the receiver element 229.

[0237] The medium 232 may be, at least in part, in the form of an air gap, or may be, at least in part, a physical medium such as glass, wood, concrete, or other building materials. The wireless power transfer system 200 may be tailored to the particular medium 232, e.g., the thickness of the medium or the material properties of the medium. Changing the properties of the medium 232, e.g., the thickness, or changing the medium altogether, e.g., introducing other materials into the space between the transmitter 210 and the receiver 220, may result in less-than-optimal wireless power transfer between the transmitter 210 and the receiver 220. Tuning the system 200 may not be optimal for the new, changed medium 232 or new medium specifications or parameters. As a result, power transfer from the transmitter 210 to the receiver 220 may be less-than-optimal, e.g., the average power transfer efficiency may be reduced. Adjusting the wireless power transfer to account for changes to the medium 232 may correspondingly improve the average power transfer efficiency. The present disclosure may result in such improved average power transfer efficiency.

[0238] For example, system 200 can wirelessly transmit power through a medium 232 having a thickness of 15 mm. The medium 232 may be removed and replaced with a medium 232 having a thickness of 30 mm, and power transmission continues as efficiently as it did at 15 mm. Furthermore, medium 232 may be of dynamic thickness, meaning that the thickness of the medium, and therefore the separation, between transmitter 210 and receiver 220 can be varied without significantly affecting power transmission. For example, consider two panes of glass separated by a distance of 15 mm. If the panes are further separated to 30 mm, power transmission is maintained and continues as efficiently as with a separation of 15 mm, with no noticeable change in power transmission and no external modifications required. In another example, transmitter 210 and receiver 220 may be relocated relative to a portion of the medium such that the separation distance between transmitter 210 and receiver 220 changes. System 200 self-optimizes based on the material and distance between transmitter 210 and receiver 220, as determined by medium 232. While the average power transfer efficiency may change when the medium 232 changes as described, the change, e.g., degradation, is less significant than in conventional systems where the inverter input voltage (DC / DC converter output voltage) is not changed in response to changes in the medium 232.

[0239] The wireless power transfer system 200 may include a high frequency wireless power transfer system as described in the '328 application. The high frequency wireless power transfer system is an inductive system. Those skilled in the art will appreciate that the high frequency wireless power transfer system may be configured to transfer power via high frequency magnetic inductive coupling or high frequency capacitive coupling. In a magnetic inductively coupled system, the majority of the power transfer is via a magnetic field. Little, if any, power is transferred via capacitance or resonant capacitance (electric field). In a capacitively coupled system, the majority of the power transfer is via an electric field. Little, if any, power is transferred via magnetic induction or resonant magnetic induction.

[0240] The high frequency wireless power transfer system is configured to transfer power by high frequency magnetic field coupling. The transmitter 210 of the high frequency wireless power transfer system is configured to operate at a given frequency, and the receiver 220 is configured to operate at the operating frequency of the transmitter 210.

[0241] As shown in FIG. 3 , the transmitter 210 is positioned adjacent to the medium 232. The transmitter 210 may be affixed to the medium 232. For example, the transmitter 210 may be affixed to a window of a building. The medium 232 may be a fabricated material and may be fabricated from any type of material or combination of materials that is not conductive or magnetic, such as wood, glass, stone, brick, concrete, or plastic, except for materials or combinations of materials that cause premature termination of fields, i.e., act as a shield. For example, a medium including a wall covered with foil-backed insulation may terminate the generated fields and act as a shield, preventing wireless power transfer between the transmitter 210 and the receiver 220.

[0242] However, a medium 232 comprised of non-shielded material with fragments of partially shielded material may still allow wireless power transfer through the fragments. For example, a medium including a wall made of wood, insulation, vinyl siding with small amounts of embedded nails / staples or other metal material may not terminate the generated field and still allow wireless power transfer between the transmitter 210 and receiver 220.

[0243] Additionally, the medium 232 may include one or more coatings, such as a coating on glass. For example, the medium 232 may include glass with a metal oxide coating, such as silver (Ag, Ag2, or Ag3). Because the coating has an extremely thin skin depth, the coating may not interfere with wireless power transmission through the glass. These coatings are often conductive, but the coating thickness is typically on the order of tens of nanometers or less. While the coating may be conductive, the thickness is small compared to the wavelength of the wireless power system operating frequency (the layer thickness is small compared to the skin depth at the system operating frequency). Thus, the field generated by the transmitter, e.g., the transmitter element, can penetrate the coating to be received by the receiver, e.g., the receiver element. While some power may be lost due to the presence of the coating, this is generally small. The amount of power dissipated in the coating may depend on the coating material, layer thickness, and system operating frequency.

[0244] Additionally, medium 232 may include a frame or edge, such as a metal window frame. Again, this generally does not terminate power transmission, even if a transmitter and receiver are located on either side at a corner of medium 232 adjacent to the frame or edge. Again, power may be dissipated in the frame or edge, thereby reducing power transmission efficiency. The amount of power dissipated may depend on the frame or edge material, thickness, and system operating frequency.

[0245] The receiver 220 is positioned on the opposite side of the medium 232, such that the medium 232 is directly between the transmitter 210 and the receiver 220. The transmitter 210 and the receiver 220 may therefore be coplanar, i.e., in the same plane through the medium. Those skilled in the art will recognize that more than one transmitter 210 and receiver 220 are contemplated.

[0246] In this embodiment, the transmitter 210 includes a described transmitter element 222, which may take the form of an inductive coil or inductor, and the receiver 220 includes a described receiver element 229, which may take the form of an inductive coil or inductor. Those skilled in the art will recognize that more than one transmitter element 222 and / or receiver element 229 are contemplated.

[0247] The transmitter element 222 may operate in current mode output (constant current output), in which the transmitter 210 is configured to generate a magnetic field without requiring the receiver 220 to be located near the transmitter 210.

[0248] Generally, a current-mode output radio frequency wireless power transfer system differs from a voltage-mode output (constant voltage output) radio frequency wireless power transfer system because a voltage-mode output transmitter 210 cannot generate and maintain a magnetic field without the presence of a receiver 220 near the transmitter 210. Without a receiver 220 in a voltage-mode output radio frequency wireless power transfer system, the transmitter 210 essentially operates in a short-circuit state and therefore cannot sustain the generation of a magnetic field.

[0249] Power transfer from transmitter 210 to receiver 220 occurs through medium 232. To maximize the coupling coefficient value and highest power transfer efficiency, transmitter 210 and receiver 220 must be optimally aligned. Optimal alignment of transmitter 210 and receiver 220 can be problematic if material 230 is opaque or if material 230 completely blocks the view of either or both of transmitter 210 and receiver 220.

[0250] In optimal alignment of receiver 220 with transmitter 210, receiver element 229 is in optimal alignment with transmitter element 222. Transmitter 210 and receiver 220 may be optimally aligned by methods and apparatus described in applicant's U.S. patent application Ser. No. 17 / 083,735, relevant portions of which are incorporated herein.

[0251] 4, the receiver 220 of the system 200 is shown in more detail. As configured, the circuit 224 includes an input stage 250, a trigger circuit 252, a rectifier element 254, a gate driver 256, and an auxiliary DC / DC converter 258.

[0252] The receiver element 229 is electrically connected to the input stage 250 and the trigger circuit 252. The receiver element 229 is configured to receive power from a transmitter, e.g., transmitter 210, using resonant or non-resonant electric or magnetic field coupling. The receiver element 229 may draw power from the transmitter by non-resonant or non-resonant magnetic or electric field coupling. Thus, the receiver element 229 includes one or more receiving coils (i.e., inductors) or one or more capacitive electrodes. Each corresponding transmitter includes a corresponding transmitting coil (i.e., inductor) or capacitive electrode.

[0253] The receiver element 229 draws power from the transmitter and therefore outputs an input voltage or signal Vin that corresponds to the drawn power or signal.

[0254] Input stage 250 is electrically connected to rectifier element 254, receiver element 229, and trigger circuit 252. Input stage 250 is adapted to perform any combination of three functions. Specifically, input stage 250 is intended to convert an impedance presented by rectifier element 254 that is below a nominal loading to an optimal load impedance for receiver element 229. Input stage 250 is intended to reduce harmonic components generated by the nonlinear action of rectifier element 254 so that receiver 220, and thus the wireless power system of which receiver 220 forms a part, can meet international product requirements related to electromagnetic compatibility (EMC). Input stage 250 is intended to ensure that the current input to rectifier element 254 is approximately sinusoidal.

[0255] In this embodiment, input stage 250 comprises a matching network or circuit. Various matching networks are contemplated. In this embodiment, the matching network takes the form of a two-stage impedance inverter. The two-stage impedance inverter is electrically connected to receiver element 229. Input stage 250 may further comprise additional filtering added in series with rectifier element 254. The use of a dual impedance inverter topology may advantageously ensure that rectifier element 254 is powered by a quasi-constant voltage source. Although a two-stage impedance inverter is described, those skilled in the art will appreciate that the matching network may take the form of a single-stage impedance inverter.

[0256] Input stage 250 is configured to ensure an optimal impedance presented to receiver element 229 at full power conditions of wireless power transfer system 200. Input stage 250 may also maintain the quasi-voltage source behavior of receiver element 229 such that the output of the synchronous rectifier exhibits a stable DC voltage from no-load to full-load conditions.

[0257] The rectifier element 254 is electrically connected to the input stage 250 , the primary receiver DC / DC converter 226 , or primary receiver DC / DC converter, and the auxiliary DC / DC converter 258 .

[0258] The rectifier element 254 includes an amplifier. The amplifier is a class E amplifier. The amplifier comprises a gate driver 256 and a main switch. The gate driver 256 drives the main switch of the amplifier. In this embodiment, the main switch comprises an n-type MOSFET 260. Although an n-type MOSFET 260 is shown, one skilled in the art will appreciate that other FETs and switching devices may be used.

[0259] The DC / DC converter 226 is electrically connected to the rectifier element 254, the auxiliary DC / DC converter 258, and the load 228, e.g., a DC load. The primary receiver DC / DC converter 226 is for receiving the DC power signal Vrect output from the rectifier element 254. The DC / DC converter 226 connects the rectifier element 254 to the load 228. The DC / DC converter 226 is for converting the received DC power signal. The converted DC power signal is output from the DC / DC converter 226 to the load 228.

[0260] An auxiliary DC / DC converter 258 is additionally electrically connected to the input of the primary receiver DC / DC converter 226. The auxiliary DC / DC converter 258 is electrically connected to the DC / DC converter 226, the trigger circuit 252, and the gate driver 256 of the rectifier circuit 254. The auxiliary DC / DC converter 258 is for converting Vrect output by the rectifier element 254 into an auxiliary voltage range Vaux, for example, in the range of 5 V, for powering the trigger circuit 252 and the gate driver 256. The auxiliary power supply voltage or signal Vaux powers the trigger circuit 252 and the gate driver 256. Until the auxiliary DC / DC converter 258 is ready to regulate, the FET 260 of the rectifier element 254 is off, and the rectifier element 254 functions as a passive (diode) rectifier. In this embodiment, the auxiliary DC / DC converter 258 includes a low-power buck converter.

[0261] The gate driver 256 is electrically connected to the rectifier element 254, the auxiliary DC / DC converter 258, and the trigger circuit 252. The gate driver 256 is powered by a signal, e.g., Vaux, from the auxiliary DC / DC converter 258. The gate driver 256 outputs a signal to switch the FET 260 of the rectifier element 254. In particular, the gate driver 256 outputs a gate drive voltage or gate signal, Vgate, to control the operation of the rectifier element 254, e.g., to control the switching of the FET 260 of the rectifier element 254.

[0262] The trigger circuit 252 is electrically connected to the rectifier element 254. The trigger circuit 252 is for synchronizing the wireless power transfer. The trigger circuit 252 is further electrically connected to the receiver element 229 and the input stage 250. To address the issue of non-negligible propagation delay from the gate driver 256 and the trigger circuit 252, the trigger circuit 252 is designed such that the trigger circuit 252 further delays the output signal Vtrig to ensure that Vgate is synchronized with Vin.

[0263] A load 228 is electrically connected to the DC / DC converter 226. The load 228 receives the signal Vout output by the DC / DC converter 226. The load 228 may be variable. As one skilled in the art will appreciate, the load 228 may be connected directly to the rectifier element 254 and receive Vrect if DC conversion is not required.

[0264] The gate signal, Vgate, controls the flow of current between the source and drain of FET 260, and therefore the rectification of the input signal, Vin, received at receiver element 229. Because the gate signal is in phase with the input signal, FET 260 operates as a class E inverter. Class E inverters generally operate with high efficiency, resulting in a highly efficient rectifier.

[0265] The receiver 220 further includes a voltage detector 390 electrically connected to the microcontroller 320. The voltage detector 390 detects the rectified voltage Vrect at the output of the rectifier element 254. The detected rectified voltage signal is then transmitted to the microcontroller 320, which communicates the rectified voltage signal to the transmitter 210. The microcontroller 320 may include such a communication module to communicate the detected parameter, i.e., the rectified voltage signal, to the transmitter 210. The communication module may communicate via a communication protocol including Bluetooth, Wi-Fi, or any other suitable communication protocol.

[0266] Furthermore, while receiver 220 has been described as including input stage 250 and DC / DC converter 226, those skilled in the art will appreciate that other configurations are possible. In particular, receiver 220 may not include either or both of input stage 250 and DC / DC converter 226.

[0267] 5, a block diagram of a portion of circuit 224 is shown. In particular, a block diagram of trigger circuit 252 and gate driver 256 is shown. As shown in FIG. 4, an input voltage or signal Vin is sampled by sampling circuit 260 and provided to delay line 262. In this embodiment, sampling circuit 260 is a voltage divider, and delay line 262 is a lumped element delay line circuit. The output of delay line 262 is provided to comparator circuit 264. Comparator circuit 264 is for generating a clock signal by comparing the delayed signal (Vd) output by delay line 262 with a DC level.

[0268] The resulting trigger voltage (Vtrig) is provided to gate driver 256, which converts the trigger voltage into a suitable waveform (Vgate) to drive FET 260 of rectifier element 254. Both comparator circuit 264 and gate driver 256 have propagation delays on the order of nanoseconds, which can be significant when dealing with switching periods of approximately 73.7 ns (for an operating frequency of 13.56 MHz) or 36.9 ns (for an operating frequency of 27.12 MHz). Sampling circuit 260, delay line 262, and comparator circuit 264 form trigger circuit 252. These elements are designed to ensure that Vgate is synchronized with Vin.

[0269] 6, there is shown a schematic diagram of another portion of circuit 224. This schematic diagram shows an exemplary configuration of comparator circuit 264 and gate driver 256. As previously mentioned, comparator circuit 264 is for generating a clock signal by comparing the delayed signal (Vd) output by delay line 262 with a DC level.

[0270] 6, the comparator circuit 264 includes a comparator 280 (A1) powered from an auxiliary source having an auxiliary supply voltage (Vaux). The inputs of the comparator 280 are biased to approximately one-half of Vaux. For the positive comparator input (V+), this is achieved using two equal-value resistors 282, 284, each having a resistance of R2. For the negative comparator input (V−), this is achieved using two equal-value resistors 286, 288, each having a resistance of R1.

[0271] The delayed voltage signal (Vd) output by delay line 262 is coupled to the negative comparator input (V-) through a DC blocking capacitor 290 having a capacitance of (Cb), so that the trigger voltage (Vtrig) is inverted (180 degrees out of phase) with respect to the delayed voltage signal (Vd). In terms of the total delay required to ensure that Vgate is in phase with Vin, this effectively corresponds to half a switching period, thus reducing the burden on delay line 262.

[0272] During operation, the rectified voltage Vrect is detected by the voltage detector 390. The detected rectified voltage Vrect is then communicated by the receiver microcontroller 320 to the transmitter 210. The transmitter 210 then controls the output voltage of the DC / DC converter 214, i.e., the input voltage to the inverter 216, based on the communicated rectified voltage, as described below. The output voltage, i.e., the input voltage to the inverter 216, determines the strength of the magnetic / electric field generated by the transmitter element 222. Thus, the field strength can be varied based on the rectified voltage at the receiver 220.

[0273] If the characteristics or parameters of the medium 232 between the receiver 220 and the transmitter 210 change, the rectified voltage Vrect will be affected as a result. For example, if the system 200 is tuned for a medium with a specific thickness, i.e., a certain separation distance between the transmitter 210 and the receiver 220, using the system 200 on a medium with a different thickness may result in a decrease in the transmitted average power and a decrease in the average power transfer efficiency. This may require readjustment of the system 200. However, the rectified voltage Vrect will be affected as a result of the change in thickness. The rectified voltage Vrect is detected by the voltage detector 390 and communicated to the transmitter 210 by the receiver microcontroller 330, so that the transmitter 210 can change the field strength by appropriately changing the output voltage of the DC / DC converter 214. The transmitted average power and the average power transfer efficiency are thereby increased, and power transfer between the transmitter 210 and the receiver 220 is optimized. When the field strength is changed to account for changes in the medium 232, power losses in the receiver 220 and / or transmitter 210 are reduced, thereby improving, eg, increasing, the average power transmitted and / or the average power transfer efficiency.

[0274] In particular, the output voltage of DC / DC converter 214 may be changed from a first voltage level to a second voltage level based on the rectified voltage. A voltage detector may monitor the rectified voltage Vrect over a period of time, and if the rectified voltage Vrect changes significantly enough in a short enough time, the controller 320 communicates the new rectified voltage Vrect to the transmitter 210 to change the output voltage to the second level. For example, if the rectified voltage Vrect drops by 4 V in 1 s, the controller 320 in the receiver 210 or the controller in the transmitter may decide to increase the DC / DC converter 214 output voltage (inverter 216 input voltage). If the rectified voltage Vrect rises by a similar amount in a similar time frame, the controller in the transmitter may decide to control the DC / DC converter 214 to decrease its output voltage (inverter 216 input voltage).

[0275] Decision-making by the controller in the transmitter is based on the relationship between the inverter 216 input voltage (the output voltage of the DC / DC converter 214) and the rectified voltage. If the rectified voltage is higher than expected, it may indicate that the receiver 220 is closer to the transmitter 210 than expected, i.e., the separation distance has decreased and the medium 232 has decreased in thickness or width. On the other hand, if the rectified voltage is lower than expected, it may indicate that the receiver 220 is farther from the transmitter 210 than expected. The expected rectified voltage may be the rectified voltage at which the receiver 220 is operating. The rectified voltage may be higher than expected as a result of changes in the medium other than distance, such as composition. For example, if the system 200 is operating through a medium containing glass but is then moved to operate through a medium containing wood, the rectified voltage may decrease.

[0276] When the controller of transmitter 210 receives the rectified voltage from receiver 220, i.e., from receiver controller 230, the controller in transmitter 210 may initiate an optimization sequence in which the inverter 216 input voltage (DC / DC converter 214 output voltage) is increased or decreased based on the received rectified voltage.

[0277] For example, the initial input voltage may be 10 V. This voltage is used to generate a field in the transmitter element 224. The rectified voltage at the receiver 220, which relates to the power extracted from the generated field, is communicated to the transmitter 210. A controller in the transmitter 210 then decides whether to increase or decrease the input voltage. This decision could be to go for a higher inverter 216 input voltage if the rectified voltage Vrect is within an acceptable range (determined by experimentation), or to turn off the system 200 / restart optimization if the rectified voltage Vrect is too high or too low. Turning off the system 200 could mean reducing the input voltage to 0 V so that no field is generated.

[0278] If the rectified voltage Vrect is too high, the receiver 220 may be too close to the transmitter 210. A high rectified voltage Vrect at the receiver 220 may damage electrical components, such as diodes, in the receiver. Therefore, the input voltage must remain low to prevent damage that would adversely affect the regulation of the switch nodes in the receiver.

[0279] If the rectified voltage Vrect is too low, the receiver 220 may be too far away from the transmitter 210. In this case, there may not be enough power drawn to power the load 228 of the receiver 220, or the current to the rectifying elements of the receiver 220 may be too high (because the voltage is low), which may result in excessive heating or unstable power transfer in the receiver.

[0280] Additionally, the controller in the transmitter 210 may increase the input voltage based on the ratio of the input voltage to the rectified voltage. For example, a rectified voltage of 50V may indicate that the receiver 220 is too close to the transmitter 210 if the input voltage is only 5V. However, a rectified voltage of 50V may be acceptable if the input voltage is 20V.

[0281] Although the controller is described as being in the controller, in an alternative configuration, the controller is in the receiver. The controller in the receiver sends a signal to the transmitter 210 to increase or decrease the inverter 216 input voltage (DC / DC converter 214 output voltage) based on the rectified voltage. All of the described decision-making is performed by the controller in the receiver, which simply sends control signals to the transmitter 210.

[0282] While receiver 220 has been described as including circuit 224 functioning as a synchronous rectifier, those skilled in the art will appreciate that other configurations are possible. For example, circuit 224 may operate as an asynchronous rectifier as previously described. In this configuration, voltage detector 390 detects the rectified voltage Vrect, and this signal is communicated to receiver controller 320 for transmission to transmitter 210 as described. Additionally, voltage detector 390 may be eliminated. In this configuration, rectified voltage Vrect is provided directly to the input of receiver microcontroller 330, which communicates the rectified voltage value to transmitter 210.

[0283] While the described system 200 may transmit power wirelessly, it may be desirable to send data from the receiver 220 to the transmitter 210. For example, it may be desirable to transmit data during operation of the wireless power transfer system 200 to send relevant data regarding the operating status of the receiver 220, such as DC voltage, current, temperature, and customer data (e.g., battery charge). The data may then be used by the transmitter 210 for decision-making regarding authentication, protection, and operation of the system 200. Additionally, customer data may be transmitted from the receiver 220 to the transmitter 210, which may then be transmitted to an end user using commonly used communication methods such as Wi-Fi, Ethernet, Bluetooth, or USB.

[0284] To send data from the receiver to the transmitter in some wireless power transfer systems, a dummy load is introduced at the receiver to change the load condition. The dummy load, e.g., a resistor, is introduced in series with the output of the receiver's rectifier element via a switch connection. By turning the switch on and off, the load condition of the system is changed, and this change can be detected at the transmitter and modulated to receive data from the receiver.

[0285] This method presents several drawbacks. For example, the baud rate, or transmission rate, of data transmitted from the receiver to the transmitter is limited by the value of the dummy load and the total DC capacitance at the output of the rectifier element. Using a smaller dummy load can increase the baud rate, but this increases the power loss in the dummy resistor and causes component heating. Also, reducing the value of the capacitor at the output of the rectifier element, or the input capacitor of the receiver's DC / DC converter, can result in unstable operation of the wireless power transfer system.

[0286] Other wireless power transfer systems involve modulating a capacitor at the switch node of the rectifier element instead of a dummy resistive load at the output of the rectifier element. While this technique can be effective for passive rectifier elements, in synchronous rectifier elements such as the described circuit 226, the off-capacitance can detune the zero-voltage switching (ZVS) of the rectifier element. Detuning ZVS can reduce the efficiency of the rectifier element, resulting in an overall reduction in power transfer in the system.

[0287] As described, the receiver microcontroller 330 may communicate the rectified voltage Vrect using known communication protocols. However, other methods of communicating the rectified voltage Vrect are contemplated. In accordance with the present disclosure, a method and controller for communicating between a receiver of a wireless power transfer system and a transmitter of the wireless power transfer system is provided, the receiver including a synchronous rectifier.

[0288] 7, a receiver 300 is shown according to one embodiment of the present disclosure. The receiver 300 includes a receiver element 302, an input stage 304, a trigger circuit 306, a rectifier element 308 having a gate driver 310 and a FET 312, an auxiliary DC / DC converter 314, a DC / DC converter 316 (i.e., the primary receiver DC / DC converter), a low dropout (LDO) regulator 318, a microcontroller 320, and a load 322.

[0289] The receiver element 302 is electrically connected to the input stage 304 and the trigger circuit 306. The receiver element 302 is the same as the receiver element 229 unless otherwise specified. The receiver element 302 extracts wireless power from the field generated by the transmitter of the wireless power transfer system. The extracted or received voltage is represented by Vin.

[0290] The input stage 304 is electrically connected to the rectifier element 308, the trigger circuit 306, and the receiving element 302. The input stage 304 is the same as the input stage 250 unless otherwise specified.

[0291] Rectifier element 308 is electrically connected to input stage 304, trigger circuit 306, auxiliary DC / DC converter 314, DC / DC converter 316, LDO regulator 318, and microcontroller 320. Rectifier element 308 is the same as rectifier element 254 unless otherwise specified. In the illustrated configuration, gate driver 310 of rectifier element 308 is electrically connected to microcontroller 320 such that microcontroller 320 can control the operation of gate driver 310 as described below.

[0292] The trigger circuit 306 is electrically connected to the rectifier element 308, the input stage 304, the receiver element 302, the auxiliary DC / DC converter 314, and the microcontroller 320. The trigger circuit 306 is the same as the trigger circuit 252 unless otherwise specified. In the illustrated configuration, the microcontroller 320 may control the operation of the trigger circuit 306 as described below.

[0293] Auxiliary DC / DC converter 314 is electrically connected to trigger circuit 306, gate driver 310, LDO regulator 318, rectifier element 308, DC / DC converter 316, and microcontroller 320. Auxiliary DC / DC converter 314 is the same as auxiliary DC / DC converter 258 unless otherwise specified. In the illustrated configuration, microcontroller 320 may control the operation of auxiliary DC / DC converter 314 as described below.

[0294] DC / DC converter 316 is electrically connected to LDO regulator 318, auxiliary DC / DC converter 314, and rectifier element 308. DC / DC converter 316 is the same as DC / DC converter 226 unless otherwise specified.

[0295] A load 322 is electrically connected to the DC / DC converter 316. The load 322 is the same as the load 228 unless otherwise specified.

[0296] The LDO regulator 318 is electrically connected to the DC / DC converter 316, the rectifier element 308, and the auxiliary DC / DC converter 314. The LDO regulator 318 is adapted to supply power to the microcontroller 320.

[0297] The receiver 300 further comprises a voltage detector 390 electrically connected to the microcontroller 320. The voltage detector 390 detects the rectified voltage Vrect at the output of the rectifier element 308. The detected rectified voltage signal is then transmitted to the microcontroller 320, which communicates the rectified voltage signal to the transmitter 210.

[0298] In particular, the microcontroller 320 is adapted to selectively alter the operation of elements of the receiver 300. In particular, the microcontroller 320 is adapted to alter the operation of the synchronous rectifier of the receiver 300, e.g., the rectifier element 308, the trigger circuit 306, and the auxiliary DC / DC converter 314. The microcontroller 320 is adapted to selectively enable and disable the synchronous rectifier to affect parameters detectable at the transmitter. The microcontroller 320 may selectively enable or disable the synchronous rectifier according to a modulation scheme to communicate data to the transmitter. The parameter change may be detected and demodulated according to a known demodulation scheme to determine data sent from the wireless power transfer receiver 300 to the transmitter transferring power to the receiver 300. The microcontroller 320 may operate using a modulation scheme known to the transmitter. Alternatively, the microcontroller 320 may communicate the modulation scheme to the transmitter using the known communication methods described above. In this manner, the microcontroller 320 communicates the rectified voltage signal to a transmitter, such as transmitter 210 .

[0299] The microcontroller 320 receives input data for transmission to the transmitter. Alternatively, the microcontroller 320 may generate its own data for transmission to the transmitter. For example, the microcontroller 320 may include a timer. The microcontroller 320 may be adapted to transmit data from the timer to the transmitter, i.e., timer data. Thus, references to data transmitted to the transmitter may include data for transmission received by the microcontroller 320 and / or data for transmission generated by the microcontroller 320.

[0300] In the illustrated configuration, microcontroller 320 receives input data from voltage detector 390, which detects the rectified voltage Vrect. As one skilled in the art will appreciate, microcontroller 320 may receive the rectified voltage Vrect as a direct input for communication to the transmitter. Alternatively or additionally, microcontroller 320 may receive changes in the rectified voltage. The changes in the rectified voltage may then be communicated to the transmitter.

[0301] The microcontroller 320 is adapted to control the operation of the rectifier element 308, the trigger circuit 306, and the auxiliary DC / DC converter 314 based on input data, e.g., the rectified voltage. In particular, the microcontroller 320 controls the amount of time the synchronous rectifier is enabled and disabled, thereby encoding the data for transmission. The timing may be controlled according to a modulation scheme.

[0302] In the illustrated configuration, the microcontroller 320 has several outputs, e.g., general purpose inputs / outputs, some of which control the operation of the auxiliary DC / DC converter 314 that provides power to the gate driver 310 and trigger circuit 306, the comparators in the trigger circuit 306, e.g., comparator circuit 264, and the gate driver 310. Those skilled in the art will appreciate that the microcontroller 320 is simply electrically connected to one of these components to switch the operation of the synchronous rectifier.

[0303] The microcontroller 320 is adapted to disable the operation of any one of these components, causing the synchronous rectifier to be placed in an unloaded state. The junction capacitance of the diode in parallel with the main switch of the class E synchronous rectifier of the rectifier element 308 causes the impedance presented to the receiving element 302 to be different compared to synchronous operation. The duty cycle of the diode at the switch node of the rectifier element 308 approaches 100%. This causes an abrupt change in the impedance seen by the receiving element 302 and, consequently, by the transmitter, which is wirelessly transferring power to the receiver 300. This abrupt change in the transmitter's output impedance causes an instantaneous change in the waveform at the transmitter, which can be decoded to determine data, e.g., the rectified voltage, sent from the receiver 300 to the transmitter.

[0304] While the receivers 220, 300 have been described as including circuitry that functions as a synchronous rectifier, those skilled in the art will appreciate that other configurations are possible. For example, the rectifier may be asynchronous. In particular, the asynchronous rectifier may include a diode rectifier. Referring now to FIG. 8, a block diagram of another configuration of a receiver is shown. In this configuration, the receiver includes the same elements as the receiver 220 shown in FIG. 4, with like elements having reference numbers incremented by 1000, unless otherwise noted.

[0305] In contrast to the receiver described above, in this configuration the receiver includes a diode rectifier 1253. The diode rectifier 1253 is electrically connected to the input stage 1250 and the receiver DC / DC converter 1226. A voltage detector 1390 detects the rectified voltage at the output of the diode rectifier 1253. The diode rectifier 1253 rectifies the power signal extracted by the receiver element 1229 from the field generated by a transmitter, e.g., transmitter 210. While the configuration shown includes the input stage 1250 and the DC / DC converter 1226, those skilled in the art will appreciate that one or both of these elements may be absent.

[0306] Although not shown, receiver controller 1320 may be powered by a power supply at the receiver. For example, the receiver may further include an auxiliary DC / DC converter at the output of diode rectifier 1253 to convert the rectified signal to an appropriate range for powering receiver controller 1320. The auxiliary DC / DC converter may be electrically connected to diode rectifier 1253 and controller 1320.

[0307] As in the described embodiment, a voltage detector 1390 detects the rectified voltage at the output of the diode rectifier 1253. A receiver controller 1320, which may be in the form of a microcontroller, receives this rectified voltage as an input and communicates the rectified voltage to the transmitter from which the receiver is wirelessly receiving power.

[0308] Referring now to FIG. 9, a schematic diagram illustrates the receiver elements of FIG. 8 in more detail. As illustrated, receiver element 1229 includes two inductive elements 1231, e.g., coils, electrically connected to capacitors C100 and C101. Capacitors C100 and C101 are receiver resonator capacitors. In the illustrated configuration, receiver element 1229 is shown as including two elements, although fewer or more elements may be present. Furthermore, as will be appreciated by those skilled in the art, the receiver element may include a capacitive element, e.g., an electrode, electrically connected to an inductor, i.e., a capacitive electrode and inductor pair instead of an inductive element and capacitor pair. In this configuration, the receiver draws power from the generated electric field rather than the magnetic field.

[0309] Capacitors C100 and C101 are electrically connected to input stage 1250. Input stage 1250 includes an LC circuit consisting of a capacitor / inductor C102 / L100 LC pair and a capacitor / inductor C103 / L101 pair. Capacitors C102 and C103 are grounded at their midpoint terminals. The LC circuit filters high-frequency components from receiver element 1229 for electromagnetic compatibility (EMC) while allowing the main power signal at the receiver's operating frequency to pass. Thus, the LC circuit forms a single-stage LC filter. Input stage 1250 further includes capacitors C104 and C105 to block low-frequency components.

[0310] Although a single-stage LC filter is shown here, those skilled in the art will appreciate that input stage 1250 may include any other topology, including a double-impedance inverter, a single-impedance inverter, or any other filter / matching network. As those skilled in the art will appreciate, capacitors C104 and C105 are optional and may or may not be included. Furthermore, as those skilled in the art will appreciate, input stage 1250 may not be included in its entirety.

[0311] Input stage 1250 is electrically connected to diode rectifier 1253, which includes diodes D100, D101, D102, and D103 that form a full-bridge diode rectifier. The full-bridge diode rectifier is electrically connected to capacitors C106-C111. Capacitors C106-C111 provide output voltage filtering and smoothing. Diode rectifier 1253 converts an alternating current (AC) signal at its input to a direct current (DC) signal at its output.

[0312] 9, the output of the diode rectifier 1253 is electrically connected to the DC / DC converter 1226. Furthermore, a voltage detector 1390 detects the rectified voltage at the output of the diode rectifier 1253.

[0313] Because diode rectifier 1253 is asynchronous, there is no synchronous rectifier to switch to communicate the rectified voltage. Rather, in this configuration, communication between the illustrated receiver and transmitter is accomplished by either switching a resistor at the output of diode rectifier 1253 or switching a capacitor at the input of diode rectifier 1253 to modulate data onto the main power signal. This switching is accomplished by controlling a MOSFET connected to either the resistor or capacitor.

[0314] In the illustrated configuration, a capacitor is switched at the input of the diode rectifier 1253. This input connection is indicated by the arrow Rx2TxIB in FIG. 9. Referring to FIG. 10, a circuit diagram of the switching circuit forming portion of the receiver is shown. As shown in FIG. 10, a capacitor C502 is connected at the input of the diode rectifier 1253. A resistor R500 is connected directly to the input of the diode rectifier 1253 by the node Rx2TxIB. In the illustrated configuration, the resistor R500 is a 0 ohm jumper, but the resistor R500 could also be a resistor of some non-zero value. As those skilled in the art will appreciate, the resistor R500 may be omitted. If the resistor R500 is not included, the capacitor C502 is connected directly to the input of the diode rectifier 1253.

[0315] The IBSW control node shown in FIG. 10 is electrically connected to a receiver controller 1320. The controller 1320 controls the operation of a MOSFET Q500. The receiver controller 1320 is connected to the MOSFET Q500 through a resistor R501. While the MOSFET Q500 is shown as including diodes D501 and D502 connected between pins 3 and 4 and 8, those skilled in the art will appreciate that these diodes D501 and D502 may be omitted. In the illustrated configuration, resistor R501 is a 0 ohm jumper, but resistor R501 may also be a resistor of some non-zero value. As those skilled in the art will appreciate, resistor R501 may also be omitted.

[0316] In use, the receiver controller 1320 controls the operation of the MOSFET Q500 to selectively charge a capacitor C502 electrically connected to the input of the diode rectifier 1253 to modulate data onto the main power signal. The receiver controller 1320 modulates the main power signal to encode the detected rectified voltage for communication with the transmitter.

[0317] 8-10 as communicating the rectified voltage in certain manners, those skilled in the art will appreciate that other configurations are contemplated. For example, the receiver controller 1320 may include a communications module that communicates the rectified voltage to the transmitter via a communications protocol, including Bluetooth, Wi-Fi, or any other suitable communications protocol.

[0318] As described, receiver 300 communicates data, e.g., a rectified voltage, to a transmitter, e.g., transmitter 210. The transmitter receives the communicated data and controls the output voltage of DC / DC converter 214. Referring now to Figure 11, one embodiment of transmitter 330 according to an aspect of the present disclosure is shown. Transmitter 330 is adapted for use with receiver 300 as described.

[0319] Transmitter 330 comprises a power supply 332, a DC / DC converter 334, a circuit 336 including an inverter 338 and an output stage 340, and a transmitter element 342. Power supply 332 is electrically connected to DC / DC converter 334. Power supply 332 is adapted to supply a power signal to DC / DC converter 334. Power supply 332 is adapted to supply a DC power signal to DC / DC converter 334.

[0320] DC / DC converter 334, i.e., primary transmitter DC / DC converter, is electrically connected to power source 332 and circuit 336. In particular, DC / DC converter 334 is electrically connected to inverter 338 of circuit 336. DC / DC converter 334 is adapted to convert the power signal received from power source 332 to a desired voltage level.

[0321] The circuit 336 is electrically connected to the transmitter element 342 and the DC / DC converter 334. Specifically, the inverter 338 is electrically connected to the DC / DC converter 334, and the output stage 340 is electrically connected to the transmitter element 342. The inverter 338 is also electrically connected to the output stage 340. The inverter 338 is adapted to convert the converted DC power signal from the DC / DC converter 334 into an alternating current (AC) signal. The inverter 338 may include a high-frequency power inverter. The output stage 340 is adapted to match the output impedance of the inverter 338 to an optimal impedance of the wireless power link between the transmitter element 342 and the corresponding receiving element, e.g., receiving element 229, 302, 1229. The output stage 340 is additionally or alternatively adapted to filter high-frequency harmonic components of the inverter 338. The output stage is additionally or alternatively adapted to establish a quasi-current source behavior at the connection point of the wireless link.

[0322] The transmitter element 342 is electrically connected to the circuit 336. In particular, the transmitter element 342 is electrically connected to the output stage 340. The transmitter element 342 comprises one or more inductive elements, i.e., inductors. The inductive elements may include one or more coils. The coils may include booster coils and / or shielding coils as described in applicant's U.S. patent application Ser. No. 17 / 193,539, relevant portions of which are incorporated herein by reference.

[0323] In another configuration, the transmitter element 342 includes one or more capacitive elements, e.g., capacitive electrodes. The capacitive electrodes may be laterally spaced, elongated electrodes, although one skilled in the art will appreciate that other configurations are possible, including, but not limited to, concentric electrodes, coplanar electrodes, circular electrodes, elliptical electrodes, disk electrodes, etc. Other suitable electrode configurations are described in applicant's U.S. Pat. No. 9,979,206 (B2), relevant portions of which are incorporated herein by reference. As one skilled in the art will appreciate, the transmitter element 342 may include a combination of inductive and capacitive elements.

[0324] The transmitter element 342 may generally correspond to, and may be identical to, a receiver element, e.g., a receiver element 229, 302, 1229, to enable wireless power transmission from the transmitter 330 to a receiver, e.g., a receiver 220, 300.

[0325] According to one aspect of the present disclosure, the circuit 336 further includes an LDO regulator 344, a microcontroller 346, and a detector 348. The LDO regulator 344 is electrically connected to the DC / DC converter 334, the inverter 338, and the microcontroller 346. The LDO regulator 344 is adapted to supply power to the microcontroller 346.

[0326] Microcontroller 346 is electrically connected to LDO regulator 344 and detector 348. Microcontroller 346 is adapted to decode data transmitted by the receiver to transmitter 330 based on the parameter change detected by detector 348. Microcontroller 346 is also electrically connected to DC / DC converter 334. Microcontroller 346 is adapted to control the output voltage of DC / DC converter 334 based on the decoded data. Because the data corresponds to the detected rectified voltage, microcontroller 346 controls the output voltage of DC / DC converter 334 based on the communicated (detected) rectified voltage at receiver 300, specifically at the output of rectifier element 308 of receiver 300.

[0327] The output voltage of DC / DC converter 334 is controlled to control the input voltage to inverter 338. The input voltage to inverter 338 may be controlled to vary the field generated by transmitter element 342. As explained, changes in medium 332 can adversely affect the average power transfer efficiency between transmitter 330 and receiver 300. These changes are observable by the rectified voltage at receiver 300, which is communicated to transmitter 330. Transmitter 330 controls the inverter 338 input voltage to vary the strength of the generated field, thereby improving the average power transfer efficiency to receiver 300.

[0328] The detector 348 is electrically connected to the output stage 340, or to the DC / DC converter 334 and the inverter 338. The detector is adapted to detect a change in a parameter in the transmitter 330, as described below.

[0329] The output voltage of the DC / DC converter 334 may be changed from a first voltage level to a second voltage level based on the rectified voltage. The controller 320 may monitor the rectified voltage Vrect with the voltage detector 390 over a period of time. If the rectified voltage Vrect changes significantly enough in a short enough time, the controller 320 communicates the new rectified voltage Vrect to the transmitter 330 by modifying the synchronization operation as described to change the output voltage to the second level. For example, if the rectified voltage Vrect drops by 4 V in 1 s, the controller 346 may decide to increase the DC / DC converter 334 output voltage (inverter 338 input voltage). If the rectified voltage Vrect rises by a similar amount in a similar time frame, the controller 346 may decide to control the DC / DC converter 334 to decrease its output voltage (inverter 338 input voltage).

[0330] Decision-making by the controller 346 is based on the relationship between the inverter 338 input voltage (the output voltage of the DC / DC converter 334) and the rectified voltage. If the rectified voltage is higher than expected, it may indicate that the receiver 300 is closer to the transmitter 330 than expected, i.e., the separation distance has decreased and the medium 232 has decreased in thickness or width. On the other hand, if the rectified voltage is lower than expected, it may indicate that the receiver 330 is farther from the transmitter 310 than expected. The expected rectified voltage may be the rectified voltage at which the receiver 220 is operating. The rectified voltage may be higher than expected as a result of changes in the medium other than distance, such as composition. For example, if the system 200 is operating through a medium containing glass but is then moved to operate through a medium containing wood, the rectified voltage may decrease.

[0331] Once the controller 346 receives the rectified voltage from the controller 320 at the receiver (via the synchronous switching described above), the controller 346 may begin an optimization sequence. In the sequence, the inverter 338 input voltage (DC / DC converter 334 output voltage) is increased based on the received rectified voltage. For example, the initial input voltage may be 10 V. This voltage is used to generate a field at the transmitter element 342. The rectified voltage at the receiver 300, which relates to the power extracted from the generated field, is communicated to the transmitter 330. The controller 346 then decides whether to increase or decrease the input voltage. This decision could be to go for a higher inverter 338 input voltage if the rectified voltage Vrect is within an acceptable range (determined by experimentation), or to turn off the wireless power transfer system / restart optimization if the rectified voltage Vrect is too high or too low. Turning off the system could mean reducing the input voltage to 0 V so that no field is generated.

[0332] If the rectified voltage Vrect is too high, the receiver 300 may be too close to the transmitter 330. A high rectified voltage Vrect at the output of the rectifier element 308 may damage electrical components, such as diodes, in the receiver 300. Therefore, the input voltage must remain low to prevent damage that may adversely affect the regulation of the switch nodes in the receiver 300.

[0333] If the rectified voltage Vrect is too low, the receiver 300 may be too far away from the transmitter 330. In this case, there may not be enough power drawn to power the load 332 of the receiver 300, or the current to the rectifier elements of the receiver 300 may be too high (because the voltage is low), which may result in excessive heating or unstable power transfer in the receiver 300.

[0334] Microcontroller 346 and detector 348 are described in more detail with reference to Figure 12. A portion of one embodiment of transmitter 330 is shown in more detail in Figure 12. In the configuration shown, LDO regulator 344 is powered by DC / DC converter 334 and provides power to microcontroller 346. Microcontroller 346 receives a signal from detector 348. Detector 348 outputs a logic level signal, i.e., a logic level, which microcontroller 346 decodes into data sent by the receiver to transmitter 330.

[0335] Although LDO regulator 344 has been described as being powered by DC / DC converter 334, one skilled in the art will appreciate that other configurations are possible. For example, LDO regulator 344 may be connected to a power source, such as the main power supply, that provides power to DC / DC converter 334. Alternatively, LDO regulator 344 may be powered by an auxiliary DC / DC converter that is connected to the power supply.

[0336] In the illustrated configuration, detector 348 detects a voltage waveform, i.e., detector 348 is a voltage detector. Detector 348 detects a voltage waveform based on voltage fluctuations at two nodes, e.g., V1 at the midpoint of output stage 340 and Vres-tx at the output of output stage 340. Although detector 348 is described as detecting a voltage waveform based on voltage fluctuations at two nodes, those skilled in the art will appreciate that detector 348 may be connected to only one node. For example, detector 348 may detect a voltage waveform based on voltage fluctuations Vres-tx at the output of output stage 340.

[0337] In the illustrated configuration, inverter 338 includes capacitor 350, inductor 352, gate driver 354, clock generator 356, main switch 358, diode 360, capacitor 362, capacitor 364, and inductor 366. Capacitor 350, having capacitance C3, is connected in parallel with DC / DC converter 334 and in parallel with the series combination of inductor 352, having inductance LZVS-t, and main switch 358, shown as Q1-t. In the illustrated configuration, main switch 358 includes an n-type MOSFET. While an n-type MOSFET is shown, those skilled in the art will appreciate that other FETs and switching devices may be used.

[0338] The main switch 358 is electrically connected to a gate driver 354, which is electrically connected to a clock generator 356. The gate driver 354 drives the main switch 358 of the inverter 338. The clock generator 356 is electrically connected to the gate driver 354. The clock generator 356 comprises an oscillator. Those skilled in the art will appreciate that the clock generator 356 may comprise a signal generator.

[0339] The clock generator 356 is configured to generate a clock signal to control a gate driver 354 connected to a main switch 358 to invert an input power signal from a power supply 332 (via a DC / DC converter 334) into an RF or AC signal.

[0340] Inverter 338 further includes a diode 360, denoted as D1-t, electrically connected in parallel with main switch 358, and a capacitor 362 having a capacitance CZVS-t, electrically connected in parallel with diode 360. Capacitor 362 is electrically connected to a capacitor 364 having a capacitance CZVS-t2, which is electrically connected in series with an inductor 366 having an inductance Lf-t+La-t. Main switch 358, diode 360, and capacitor 362 are connected in parallel between inductor 352 and capacitor 364.

[0341] In the illustrated configuration, the output stage 340 comprises an inductor 370 having an inductance L1-tx electrically connected in series with an inductor 372 having an inductance L1-tx, and a capacitor 374 having a capacitance C1-tx electrically connected between the shared node of the inductors 370, 372 and the return.

[0342] As described, detector 348 detects a voltage waveform based on the variation of the voltage at at least one of two nodes, e.g., V1 at the midpoint of output stage 340 and Vres-tx at the output of output stage 340. Detector 348 outputs a logic level signal, i.e., a logic level, which microcontroller 346 decodes into data transmitted by the receiver to transmitter 330, e.g., the rectified voltage at the output of rectifier element 308 of receiver 300.

[0343] The detector 348 is electrically connected to the transmitter DC / DC converter 334. In particular, the detector 348 is adapted to output a control signal to the DC / DC converter 334 based on the decoded data, e.g., the rectified voltage, to control the output voltage of the DC / DC converter 334. The output voltage of the DC / DC converter 334 is controlled to control the field strength generated by the transmitter element 342 of the transmitter 330 via the inverter 338.

[0344] 13, detector 348 is shown in more detail. Detector 348 demodulates the voltage waveform detected at the transmitter. In other words, detector 348 comprises a voltage demodulator. Detector 348 includes a scaling circuit 380, a peak detector 382, ​​a filter 384, and a signal conditioner and comparator 386.

[0345] In operation, scaling circuit 380 receives detected waveforms, e.g., V1 and Vres-tx. Scaling circuit 380 reduces the amplitude of the detected waveform to make it easier to process. The reduced-amplitude waveform is then provided to peak detector 382, ​​which converts the signal to a DC voltage. When a sudden change in the RF signal input to peak detector 382 occurs as a result of the receiver switching operation of the synchronous rectifier, the signal output from peak detector 382 changes rate. Filter 384, an input filter stage, filters this output. For example, filter 384 filters this change while blocking unwanted signal components such as high-frequency noise and DC offset. The filtered signal then passes through signal conditioner and comparator 386, which amplifies and compares the amplification to a reference level. Signal conditioner and comparator 386 may include a comparator. Signal conditioner and comparator 386 outputs a logic level signal whenever a sufficiently large modulation in the RF input voltage signal occurs.

[0346] The output logic level signal is then provided to the microcontroller 346 for decoding. The microcontroller 346 determines the time between the modulated pulses to decode / demodulate the binary sequence logic level signal representing the data transmitted from the receiver to the transmitter 330.

[0347] This is similar to the processing undertaken by a receive microcontroller 320 that receives or generates data for transmission to a transmitter, such as transmitter 330. Similar to transmit microcontroller 346, receive microcontroller 320 encodes the data to be transmitted into a time sequence of synchronous and asynchronous operation of the synchronous rectifier, resulting in changes in the waveform detected at the transmitter.

[0348] 14, a flow chart illustrating a method 400 of wireless power transfer over a medium, e.g., medium 332, between a receiver, e.g., receiver 300, and a transmitter, e.g., transmitter 330. Method 400 includes detecting 402 a rectified voltage at the output of a rectifier element 254, 308 of the receiver 200, 300 by a voltage detector 390 of the receiver 200, 300. The detecting 402 may be performed directly by the microcontroller 320 of the receiver 200, 300.

[0349] The method 400 further includes a step 404 of communicating the detected rectified voltage to a transmitter, e.g., transmitter 210, 330, by the controller 320. The controller 320 may communicate the rectified voltage using a conventional communication protocol, e.g., Wi-Fi, Bluetooth.

[0350] Alternatively, the controller 320 may communicate the rectified voltage by switching the synchronous operation of the rectifier element 308 in the manner described. Additionally, the controller 320 may communicate by controlling a MOSFET to switch a resistor at the output of the diode rectifier 1253, or by switching a capacitor at the input of the diode rectifier 1253 to modulate data onto the main power signal as described.

[0351] In this case, method 400 may further include encoding the detected rectified voltage into a time sequence to modify the operation of the synchronous rectifier. Method 400 may further include modifying the operation, which may include selectively enabling and / or disabling operation of gate driver 310, trigger circuit 306, and / or auxiliary DC / DC converter 314. Such selective switching of synchronous rectifier components occurs according to the transmitted encoded rectified voltage, such that resulting parameter changes at transmitter 330 are indicative of the rectified voltage communicated from receiver 300 to transmitter 330.

[0352] The method 400 further includes detecting 406 a parameter change in the transmitter 330 based on the change in operation of the synchronous rectifier. As described, the detector 348 detects a voltage waveform in the transmitter 330 based on the change in operation of the synchronous rectifier.

[0353] The method 400 further includes step 408 of determining, based on the parameter change, i.e., the detected parameter change, data, e.g., the rectified voltage, communicated from the receiver 300 to the transmitter 330. As described, the detector 348 processes the detected waveform and compares the processed waveform to a level to generate a logic level signal, which is decoded into data transmitted from the receiver 300 to the transmitter 330.

[0354] Such a method of communicating data may be more efficient than existing methods while allowing for higher data transmission rates. Moreover, such a method may be operable by using a receiver with a synchronous rectifier and selectively switching the operation of the synchronous rectifier to communicate data to a transmitter from which the receiver draws power.

[0355] The method may further include controlling 410, by a controller 346 of the transmitter 330, an output voltage of a DC / DC converter 334 electrically connected to the inverter 338 of the transmitter 330 based on the detected rectified voltage. By controlling the output voltage, changes in the medium observable by changes in the rectified voltage are accommodated by controlling the output voltage, potentially increasing the average power transfer efficiency between the transmitter 330 and the receiver 300.

[0356] The method may further include generating 412 a field by a transmitting resonator of the transmitter, i.e., the transmitter element 224, 342 of the transmitter 210, 330, for wirelessly transmitting power through the medium to the receiver 220, 300. The strength of the field is based on the output voltage of the converter 214, 334 (the input voltage of the inverter 216, 338).

[0357] An experimental setup of the receiver 300 and transmitter 330 was tested to evaluate performance. To emulate the presence of a fixed-coupled wireless link between the transmitter 330 and the receiver 300, an equivalent T-network was used to connect the transmitter 330 and the receiver 300 in the experimental setup. To switch the receiver 300 between synchronous and asynchronous operation, a function generator was used to enable / disable the auxiliary DC / DC converter 314 of the receiver 300, which provides power to the synchronous rectifier gate driver 310. All tests were performed under no load on the receiver 300. Operation of the receiver 300 and the transmitter 330 may also be performed under a load on the receiver 300. The experimental setup primarily used magnetic field coupling to transfer power from the transmitter 330 to the receiver 300. Furthermore, the experimental setup had an operating frequency of 13.56 MHz.

[0358] The transmitter RF voltage V1 as well as the transmitter current Iin were measured while the synchronous rectifier was modulated between synchronous and asynchronous operation. The results of this test are shown in Figures 15 through 19.

[0359] Figure 15 is a graph of the voltage and current waveforms of transmitter 330. Figure 15 shows the response of these voltage and current waveforms when receiver 300 is modulated at a frequency of 1700 Hz. As shown, the voltage waveform ranges from +18V to -18V, with peaks at +18V and -18V and valleys at +6V and -6V. The current waveform ranges from approximately 1000mA to a steady state of about 112-117mA.

[0360] 16 is a graph of the voltage rise time of transmitter 330 for an exemplary period of the voltage waveform. As shown in FIG. 16, the waveform shows a sudden increase in voltage of 2.612V during a rise time of 1.777 μs.

[0361] 17 is a graph of the voltage fall time for an exemplary period of the voltage waveform of transmitter 330. As shown in FIG. 17, during the fall time of 2.228 μs, the waveform shows a sudden decrease in voltage of 4.939V.

[0362] 18 is a graph of the current rise time for an exemplary period of the current waveform of the transmitter 330. As shown in FIG. 18, during a rise time of 31.247 μs, the waveform shows a current increase of 548.984 mA.

[0363] 19 is a graph of the current fall time for an exemplary period of the current waveform of the transmitter 330. As shown in FIG. 19, during the fall time of 46.633 μs, the waveform shows a rapid decrease in current of 612.376 mA.

[0364] These graphs show that changes in voltage and current waveforms are detectable based on changes in the operation of the synchronous rectifier to communicate data from the receiver to the transmitter.

[0365] While a particular transmitter 330 is described, one skilled in the art will appreciate that other configurations are possible. Referring now to FIG. 20, another embodiment of a portion of a transmitter is shown. In this embodiment, the transmitter includes similar components to transmitter 330, with identical elements having reference numbers incremented by 100. An LDO regulator 444 is powered by DC / DC converter 434 and provides power to a controller 446. Controller 446 receives a signal from a detector 448. Detector 448 outputs a logic level signal, i.e., a logic level, which the controller 446 decodes into data sent by the receiver to the transmitter.

[0366] In the illustrated configuration, detector 448 detects one or more current waveforms, i.e., detector 448 is a current detector. Detector 448 detects a current waveform based on fluctuations in a current at a single node, for example, Iin at the output of DC / DC converter 434.

[0367] Because the transmitter's input DC current varies according to the impedance seen, this signal, Iin, may additionally or alternatively be used as a source to a detector 448, e.g., a current demodulator, which filters the detected DC current and generates a logic level message to reflect the fluctuations in the transmitter's DC current level. This signal is then transmitted to a controller 446, e.g., a microcontroller. The controller 446 then controls the output voltage of the transmitter's DC / DC converter 434 based on the receiver's decoded rectified voltage.

[0368] 21, detector 448, a current detector, is shown in more detail. Detector 448 demodulates the current waveform detected by the transmitter, as described below. In other words, detector 448 comprises a current demodulator. Detector 448 includes a current sensing circuit 480, a filter 482, and a signal conditioner and comparator 484.

[0369] In operation, the current sensing circuit 480 detects a current signal, e.g., the input current Iin. The current sensing circuit 480 then scales the sensed current to a smaller amplitude. The current sensing circuit 480 then converts the sensed current, e.g., the scaled sensed current, into a voltage signal proportional to the sensed current. The filter 428, i.e., the input filter stage, filters this output, i.e., the converted voltage. For example, the filter 428 passes the modulated signal while blocking unwanted signal components such as high-frequency noise and DC offset. The filtered signal then passes through the signal conditioner and comparator 484, which amplifies and compares the amplification to a reference level. The signal conditioner and comparator 484 may include a comparator. The signal conditioner and comparator 484 outputs a logic level signal whenever a sufficiently large modulation in the input current Iin signal occurs.

[0370] The output logic level signal is then provided to a controller 446 for decoding. The controller 446 determines the time between the modulated pulses to decode the binary sequence of logic level signals representing the data sent from the receiver to the transmitter. The data is the rectified voltage detected at the receiver that is used to control the operation of the DC / DC converter 434.

[0371] It should be understood that the examples provided are merely illustrative of the disclosure and that various modifications may be made. [Explanation of symbols]

[0372] 100 Wireless power transmission system 110 Transmitter 112 Power supply 116 Transmitter Elements 120 receiver 124 receiver elements 128 load 200 Wireless Power Transmission System 210 Transmitter 212 Power supply 214 DC / DC converter 216 Circuits, Inverters 220 receiver 222 Transmitter Element 224 circuits 226 Primary Receiver DC / DC Converter 228 Load 229 Receiver Element 230 Wireless Link 232 Medium 250 input stage 252 Trigger Circuit 254 Rectifier element 256 gate drivers 258 Auxiliary DC / DC Converter 260 Sampling circuit / n-type MOSFET 262 Delay Line 264 Comparator circuit 280 Comparator 282 Resistor 284 Resistor 286 Resistor 288 Resistor 290 DC Blocking Capacitor 300 receiver 302 receiver element, receiving element 304 Input Stage 306 Trigger Circuit 308 Rectifier element 310 Gate Driver 312 Field Effect Transistor (FET) 314 Auxiliary DC / DC Converter 316 DC / DC Converter 318 Low Dropout (LDO) Regulator 320 Microcontroller 322 Load 330 Transmitter 332 Power supply, load 334 DC / DC Converter 336 circuits 338 Inverter 340 output stage 342 Transmitter Elements 344 LDO regulator 346 Microcontroller 348 detector 350 Capacitor 352 Inductor 354 Gate Driver 356 Clock Generator 358 Main Switch 360 Diode 362 Capacitor 364 Capacitor 366 Inductor 370 Inductor 372 Inductor 374 Capacitor 380 Scaling Circuit 382 Peak Detector 384 filters 386 Signal Conditioners and Comparators 390 Voltage Detector 434 DC / DC converter 444 LDO regulator 446 Controller 448 detector 480 Current detection circuit 482 filters 484 Signal Conditioners and Comparators 1226 DC / DC Converter 1229 receiver element 1250 input stage 1253 Diode Rectifier 1320 Receiver Controller 1390 Voltage Detector

Claims

1. 1. A method of wireless power transmission through a medium, comprising: controlling an input voltage of an inverter of a transmitter of the wireless power transfer system based on the detected parameter; generating a field by a transmitting resonator of the transmitter, the transmitting resonator being electrically connected to the inverter, for transmitting power wirelessly through a medium to a receiver of the wireless power transfer system; A method comprising:

2. Detecting the parameter at the transmitter and / or the receiver of the wireless power transfer system. The method of claim 1 further comprising:

3. The method of claim 2 , wherein the parameter comprises a rectified voltage at the receiver of the wireless power transfer system.

4. controlling the input voltage of the inverter controlling the output voltage of a converter electrically connected to the inverter; 4. The method of claim 1, comprising:

5. communicating the detected parameters to the transmitter.

5. The method of claim 1, further comprising:

6. the communicating step communicating the detected parameters from the receiver to the transmitter.

6. The method of claim 5, comprising:

7. monitoring said parameter over a period of time.

7. The method of claim 1, further comprising:

8. controlling the input voltage of the inverter controlling the input voltage of the inverter based on the change in the monitored parameter over the time period.

8. The method of claim 7, comprising:

9. 9. The method of any one of claims 1 to 8, wherein the medium comprises a window, glass, a building structure, concrete, or wood.

10. 1. A method of wireless power transmission through a medium, comprising: powering a transmitting resonator of a transmitter of a wireless power transfer system with an input voltage via an inverter to generate a field for wirelessly transferring power through a medium to a receiver of the wireless power transfer system; optimizing the input voltage of the inverter based on the detected parameters; A method comprising:

11. optimizing the input voltage adjusting the input voltage from a first voltage level to a second voltage level based on the detected parameter; 11. The method of claim 10, comprising:

12. adjusting the input voltage Sequentially adjusting the input voltage between a plurality of voltage levels.

12. The method of claim 10 or 11, comprising:

13. Detecting the parameter at the transmitter and / or the receiver of the wireless power transfer system.

13. The method of any one of claims 10 to 12, further comprising:

14. The method of claim 10 , wherein the parameter comprises a rectified voltage at the receiver of the wireless power transfer system.

15. communicating the rectified voltage from the receiver to the transmitter.

15. The method of claim 14, further comprising:

16. 16. A controller configured to control an inverter of a transmitter of a wireless power transfer system, a converter of the transmitter, and at least one of the transmitter and receiver of the wireless power transfer system to perform the method of any one of claims 1 to 15.

17. a transmitter of a wireless power transfer system for wirelessly transmitting power through a medium to a receiver of the wireless power transfer system; a transmitter resonator for wirelessly transmitting power through a medium to a receiver of the wireless power transfer system; an inverter electrically connected to the transmit resonator; a controller for controlling an input voltage of the inverter based on the detected parameters; A transmitter comprising:

18. a sensor for detecting said parameter in said transmitter and / or said receiver; 20. The transmitter of claim 17, further comprising:

19. 19. The transmitter of claim 17 or 18, wherein the parameter comprises a rectified voltage at the receiver of the wireless power transfer system.

20. a communication module for receiving the parameters from the receiver of the wireless power transmission system; 20. The transmitter of claim 17, further comprising:

21. A wireless power transmission system, a transmitter comprising a transmitter resonator for wirelessly transmitting power through a medium to a receiver of the wireless power transfer system, and an inverter electrically connected to the transmitter resonator; a receiver comprising a receiver resonator for wirelessly extracting power from the transmitter by electric and / or magnetic field coupling; a controller for controlling an input voltage of the inverter based on the detected parameters; A wireless power transmission system comprising:

22. a sensor for detecting said parameter in said transmitter and / or said receiver; 22. The system of claim 21, further comprising:

23. 23. The system of claim 21 or 22, wherein the parameter comprises a rectified voltage at the receiver of the wireless power transfer system.

24. The receiver: a communication module for communicating said parameters from said receiver to said transmitter; 24. The system of any one of claims 21 to 23, further comprising:

25. The transmitter: a communication module for receiving the parameters from the receiver; 25. The system of any one of claims 21 to 24, further comprising:

26. The transmitter: a converter electrically connected to the inverter 26. The system of any one of claims 21 to 25, further comprising:

27. 27. The system of claim 26, wherein the controller is for controlling an output voltage of the converter based on the detected parameter.

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