Method for wireless power transfer over medium

Abstract

A method of wireless power transfer over a medium is provided. The method includes controlling an input voltage of an inverter of a transmitter of the wireless power transfer system based on the detected parameter. The method further includes generating, via the transmitter, a field for wirelessly transmitting power over 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 transmitting power over a medium are also provided.

Description

Technical Field

[0001] The present disclosure relates generally to wireless power transfer, and in particular, to methods of wireless power transfer through a medium, and controllers for wirelessly transferring power through a medium. Background Art

[0002] Wireless power transfer systems, such as wireless charging, are becoming increasingly important technologies to support next-generation devices. More and more manufacturers and companies are investing in this technology, as the potential benefits and advantages it offers are evident.

[0003] Various wireless power transmission systems are known. A typical wireless power transmission 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, a transmitter has a transmitter coil with a certain inductance that transfers electrical energy from a power source to a receiver, which has a receiver coil with a certain inductance. Power transfer occurs due to 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—with a coupling factor above 0.5—and in optimal alignment for efficient power transfer.

[0005] Magnetic resonance systems also exist, in which power is transferred due to magnetic field coupling between transmitter and receiver coils or inductors. The transmitter and receiver inductors can be loosely coupled, i.e., have a coupling factor below 0.5. However, in magnetic resonance systems, the inductors resonate with at least one capacitor. Furthermore, in magnetic resonance systems, the transmitter and receiver are self-resonant. The power transfer range in magnetic resonance systems is increased compared to that of magnetic induction systems, and alignment issues are corrected. Although electromagnetic energy is generated in magnetic induction and magnetic resonance systems, most power transfer occurs via magnetic fields. Little, if any, power is transferred via electric induction or resonant electric induction.

[0006] In capacitive systems, the transmitter and receiver have capacitive electrodes. Power transfer occurs due to electric field coupling between the capacitive electrodes of the transmitter and receiver. Similar to magnetic resonance systems, there are electric resonance systems, in which the capacitive electrodes of the transmitter and receiver resonate using at least one inductor. The inductor can be a coil. In electric resonance systems, the transmitter and receiver are self-resonant. Compared to electric induction systems, electric resonance systems increase the power transfer range and correct for alignment issues. Although electromagnetic energy is generated in electric induction and electric resonance systems, the majority of power transfer occurs via electric fields. Little, if any, power is transferred via magnetic induction or resonant magnetic induction.

[0007] While some wireless power transfer systems are known, improvements and / or alternatives are needed.

[0008] This background technology is intended only to set the scene so that those skilled in the art can better understand the following description. Therefore, the above discussion should not be construed as an admission that it is part of the state of the art or common general knowledge. One or more aspects / embodiments of the present disclosure may or may not address one or more of the background technology issues. Summary of the Invention

[0009] According to one aspect of the present disclosure, a method, a controller, a transmitter, and a wireless power transmission system for wireless power transmission through a medium are provided.

[0010] A medium may be between a transmitter and a receiver of a wireless power system. The medium may be at least partially in the form of an air gap, or may be at least partially a physical medium such as glass, wood, concrete, or other building materials. A wireless power transmission system may be tuned for a specific medium (e.g., the thickness of the medium or the material properties of the medium). Changing the properties of the medium (e.g., thickness) or completely changing the medium (e.g., introducing another material in the space between the transmitter and receiver) may result in suboptimal wireless power transmission between the transmitter and receiver. The system may be suboptimally tuned for the new, altered medium or new medium characteristics or parameters. As a result, power transmission from the transmitter to the receiver may be suboptimal, e.g., with reduced average power transfer efficiency. Adjusting the wireless power transmission to account for changes to the medium may correspondingly improve the average power transfer efficiency. The described methods, controllers, transmitters, and wireless power transmission systems may provide such improved average power transfer efficiency.

[0011] According to another aspect of the present disclosure, a method for wireless power transmission through a medium is provided, the method comprising:

[0012] An input voltage of an inverter of a transmitter of the wireless power transmission system is controlled based on the detected parameter.

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

[0014] The main surfaces of the transmitting element and the receiving element of the transmitter and the receiver can be aligned, formed into parallel planes, and positioned close to the medium.

[0015] The transmitter and / or receiver can be affixed to opposing surfaces defining a medium. For example, the transmitter and / or receiver can be affixed to opposing exterior and interior surfaces of a building structure formed of wood, concrete, glass, etc. The transmitter and / or receiver can be affixed to opposing sides of a window (e.g., a glass window).

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

[0017] The method may further include:

[0018] A field for wirelessly transmitting power through a medium to a receiver of the wireless power transmission system is generated via a transmission resonator of the transmitter, the transmission resonator being electrically connected to the inverter.

[0019] The generated field may be based on the input voltage.The strength of the generated field may be based on the input voltage.

[0020] The method may further include:

[0021] The parameter is detected at a transmitter and / or receiver of the wireless power transfer system. 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.

[0022] The parameter may include a rectified voltage at a receiver of the wireless power transmission 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 a transmitter. The parameter may include a ratio of the detected rectified voltage to a voltage input to the receiver (i.e., an input voltage). The parameter may include a change in the rectified voltage detected at the receiver of the wireless power transmission system over time.

[0023] Controlling the input voltage of the inverter can include:

[0024] 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 the output voltage of the DC / DC converter is the input voltage of the inverter. The DC / DC converter may be used to regulate the 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.

[0025] The transmitter may also 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 transmitting element. The transmitting element may include a capacitive electrode and / or an inductor or an inductive coil.

[0026] The method may further include:

[0027] The detected parameters are transmitted to the transmitter.

[0028] Communications may include:

[0029] The detected parameters are transmitted from the receiver to the transmitter.

[0030] Communications may include communicating via Bluetooth, Wi-Fi, 5G, or other suitable communications protocols. Communications may include:

[0031] modifying the operation of a rectifier of a receiver of a wireless power transfer system;

[0032] detecting a parameter change at a transmitter of the wireless power transfer system based on the modification of the operation of the rectifier; and

[0033] Data transmitted from the receiver to the transmitter is determined based on the parameter change. The data may include the detected parameter.

[0034] The rectifier may include a diode rectifier. The diode rectifier may include a full-bridge diode rectifier.

[0035] Modifying the rectifier operations may include:

[0036] Switching the operation of an electrical component at the input or output of a rectifier. The electrical component may include a resistor or a capacitor. The switching operation may include switching a resistor at the output of the rectifier (e.g., a diode rectifier) ​​and / or switching a capacitor at the input of the rectifier (e.g., a diode rectifier). The switching operation may include controlling a switching element electrically connected to the electrical component. The switching element may include a FET, such as a MOSFET. A controller at the receiver may switch the operation of the electrical component.

[0037] Communications may include:

[0038] modifying the operation of a synchronous rectifier of a receiver of a wireless power transfer system;

[0039] detecting a parameter change at a transmitter of a wireless power transfer system based on a modification of the operation of a synchronous rectifier; and

[0040] Data transmitted from the receiver to the transmitter is determined based on the parameter change. The data may include the detected parameter.

[0041] Modifying the operation of the synchronous rectifiers can result in a detectable parameter change at the transmitter. Detection of this parameter change at the transmitter can be used to determine data transmitted from the receiver to the transmitter. Transmitting data from the receiver to the transmitter based on modifying the operation of the synchronous rectifiers can be more energy-efficient and allow for greater throughput than conventional communication methods.

[0042] Modifying the operation of a synchronous rectifier may include:

[0043] The synchronous rectifier is switched between synchronous and non-synchronous operation.

[0044] Modifying the operation of a synchronous rectifier may include:

[0045] Selectively enables and disables the synchronous rectifiers.

[0046] Selectively enabling and disabling the synchronous rectifiers may include enabling and disabling synchronous operation of the synchronous rectifiers. Modifying the operation of the synchronous rectifiers may include switching operations of the synchronous operation. The timing between the selective enabling / disabling or switching operations may be varied to transfer data from the receiver to the transmitter.

[0047] Selectively enabling and disabling the synchronous rectifier may include selectively enabling and disabling a portion of the synchronous rectifier. Additionally, selectively enabling and disabling the synchronous rectifier may include enabling and / or disabling one side of the synchronous rectifier in a push-pull configuration.

[0048] Synchronous rectifiers can include two-phase systems, or have a push-pull configuration. One side (or phase) of the synchronous rectifier can be synchronous, while the other side can be asynchronous.

[0049] Selectively enabling and disabling the synchronous rectifiers may include selectively enabling and disabling one side (or phase) of the synchronous rectifiers.

[0050] The synchronous rectifier may include at least one field effect transistor (FET).

[0051] The synchronous rectifier may include at least one of the following:

[0052] Rectifier element for rectifying the power signal into DC;

[0053] trigger circuit; and

[0054] A gate driver electrically connected to the trigger circuit and the rectifier element.

[0055] The gate driver may be used to control the operation of the rectifier element via a trigger signal output by the trigger circuit.The gate driver may output a gate drive voltage or gate signal that is in phase with an input voltage received at the rectifier element.

[0056] The trigger circuit can ensure proper timing of the gate drive voltage or gate signal output by the gate driver.

[0057] 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 suitable for converting 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.

[0058] The gate driver can output a gate drive voltage or a gate signal to control the operation of the rectifier element. Specifically, the gate signal can control the operation of the amplifier by controlling the operation of the FET.

[0059] The trigger circuit may include:

[0060] The sampling circuit samples the input signal.

[0061] The sampling circuit may be a voltage divider.

[0062] The trigger circuit may include:

[0063] A delay line is used to delay the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element.

[0064] The trigger circuit may include:

[0065] A comparator generates a clock signal by comparing a delayed signal output from the delay line with a DC voltage level.

[0066] The trigger circuit may include:

[0067] The RC delay circuit is used to delay the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element.

[0068] The RC delay circuit may include at least one resistor electrically connected to at least one capacitor.

[0069] The trigger circuit may include:

[0070] The comparator generates a clock signal by comparing the delayed signal output by the RC delay circuit with a DC voltage level.

[0071] The synchronous rectifier may further include an auxiliary DC / DC converter for powering at least one of the trigger circuit and the gate driver. In other words, the synchronous rectifier may include a power supply for powering at least one of the trigger circuit and the gate driver. The power supply may be powered by power received at the receiver (e.g., power received from the transmitter via wireless power transmission).

[0072] The auxiliary DC / DC converter may be electrically connected to a low dropout (LDO) regulator.

[0073] Modifying the operation of a synchronous rectifier may include:

[0074] Controlling the 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.

[0075] Controlling the operation of the trigger circuit may include:

[0076] Controlling operation of a comparator of the trigger circuit. Controlling operation of the comparator may include selectively enabling and disabling the comparator. The comparator may include comparator circuitry. The comparator may include an enable pin. Controlling operation of the trigger circuit may include selectively enabling the comparator via the enable pin.

[0077] Controlling the operation of the auxiliary DC / DC converter may include:

[0078] The auxiliary DC / DC converter can be selectively enabled and disabled to selectively power the trigger circuit and the gate driver. The auxiliary DC / DC converter can include controlling power supplied to the auxiliary DC / DC converter. The auxiliary DC / DC converter can include an enable pin. The auxiliary DC / DC converter can include selectively enabling the auxiliary DC / DC converter via the enable pin.

[0079] Detecting parameter changes can include:

[0080] Detecting the voltage or current waveform at the transmitter. The voltage or current waveform can be detected at certain nodes of the transmitter. The voltage waveform can be detected at the output stage of the transmitter. The current waveform can be detected at the input of the transmitter's inverter.

[0081] The data determined to be transmitted may include:

[0082] The detected voltage or current waveform is processed to determine the transmitted data.

[0083] Processing the detected voltage or current waveform may include:

[0084] Filtering voltage or current waveforms; and

[0085] generating a logic level based on the filtered voltage or current waveform; and

[0086] Data is decoded based on the generated logic levels.

[0087] Logic levels can reflect changes in voltage or current waveforms. For example, a change from high voltage to low voltage can represent a 1-to-0 data transmission, and a change from low voltage to high voltage can represent a 0-to-1 data transmission.

[0088] Decoding the data involves:

[0089] Determine the time intervals between logic levels; and

[0090] Decodes data based on time intervals.

[0091] The method may further include:

[0092] A parameter is monitored over a period of time.

[0093] Controlling the input voltage of the inverter can include:

[0094] The input voltage of the inverter is controlled based on the change of the monitored parameter during the time period.

[0095] Media may include:

[0096] Building structures, building materials (such as wood and concrete, walls, doors, air, plastic, water, polymers), and windows. The windows can be made of glass. The transmitter and receiver can be positioned on opposite sides of the medium. The medium can separate the transmitter and receiver so that the medium defines a volume between the transmitter and receiver.

[0097] According to another aspect, a method of wireless power transfer over a medium is provided. The method may include: powering a transmitter resonator of a transmitter of a wireless power transfer system via an inverter with an input voltage via the inverter to generate a field for wirelessly transferring power over the medium to a receiver of the wireless power transfer system; and

[0098] An input voltage to the inverter is optimized based on the detected parameters.

[0099] The fields may include magnetic fields and / or electric fields.

[0100] According to another aspect, a method for optimizing power transfer from a transmitter to a receiver of a wireless power transfer system over a medium is provided. The method may include:

[0101] An input voltage of an inverter of a transmitter of the wireless power transfer system is optimized based on the detected parameters.

[0102] Optimizing the input voltage can optimize the average power transfer efficiency between the transmitter and receiver of the wireless power transfer system.

[0103] 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.

[0104] Adjusting the input voltage may include continuously adjusting the input voltage between a plurality of voltage levels.

[0105] Optimization methods may also include:

[0106] The parameter is detected at a transmitter and / or receiver of the wireless power transfer system. 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.

[0107] The parameter may include a rectified voltage at a receiver of the wireless power transfer system. The rectified voltage may be a rectified power signal extracted from a field generated by a transmitter.

[0108] The method may further include:

[0109] Transfers the rectified voltage from the receiver to the transmitter.

[0110] Communications may include:

[0111] The detected parameters are transmitted from the receiver to the transmitter.

[0112] Communications may include communicating via Bluetooth, Wi-Fi, 5G, or other suitable communications protocols. Communications may include:

[0113] modifying the operation of a rectifier of a receiver of a wireless power transfer system;

[0114] detecting a parameter change at a transmitter of the wireless power transfer system based on the modification of the operation of the rectifier; and

[0115] Data transmitted from the receiver to the transmitter is determined based on the parameter change. The data may include the detected parameter.

[0116] The rectifier may include a diode rectifier. The diode rectifier may include a full-bridge diode rectifier.

[0117] Modifying the rectifier operations may include:

[0118] Switching the operation of an electrical component at the input or output of a rectifier. The electrical component may include a resistor or a capacitor. The switching operation may include switching a resistor at the output of the rectifier (e.g., a diode rectifier) ​​and / or switching a capacitor at the input of the rectifier (e.g., a diode rectifier). The switching operation may include controlling a switching element electrically connected to the electrical component. The switching element may include a FET, such as a MOSFET. A controller at the receiver may switch the operation of the electrical component.

[0119] Communications may include:

[0120] modifying the operation of a synchronous rectifier of a receiver of a wireless power transfer system;

[0121] detecting a parameter change at a transmitter of a wireless power transfer system based on a modification of the operation of a synchronous rectifier; and

[0122] Data transmitted from the receiver to the transmitter is determined based on the parameter change. The data may include the detected parameter.

[0123] The wireless power transfer system described may be a high frequency wireless power system such as that described in the applicant's U.S. provisional application No. 17 / 018328, a resonant capacitive coupled wireless power transfer system such as that described in the applicant's own U.S. patent application No. 9653948B2, or a bidirectional wireless power transfer system such as that described in the applicant's own U.S. patent application No. 17 / 899711, relevant portions of which are incorporated herein.

[0124] Modifying the operation of the synchronous rectifier can result in a detectable parameter change at the transmitter. Detection of this parameter change at the transmitter can be used to determine the data transmitted from the receiver to the transmitter. Transmitting data from the receiver to the transmitter based on modifying the operation of the synchronous rectifier can be more power efficient and allow for greater throughput than conventional communication methods.

[0125] Modifying the operation of a synchronous rectifier may include:

[0126] The synchronous rectifier is switched between synchronous and non-synchronous operation.

[0127] Modifying the operation of a synchronous rectifier may include:

[0128] Selectively enables and disables the synchronous rectifiers.

[0129] Selectively enabling and disabling the synchronous rectifiers may include enabling and disabling synchronous operation of the synchronous rectifiers. Modifying the operation of the synchronous rectifiers may include switching the operation of the synchronous operation. The time between selectively enabling / disabling or switching operations may be varied to transfer data from the receiver to the transmitter.

[0130] Selectively enabling and disabling the synchronous rectifier may include selectively enabling and disabling a portion of the synchronous rectifier. Additionally, selectively enabling and disabling the synchronous rectifier may include enabling and / or disabling one side of the synchronous rectifier in a push-pull configuration.

[0131] Synchronous rectifiers can include two-phase systems or have a push-pull configuration. One side (or phase) of the synchronous rectifier can be synchronous, while the other side can be asynchronous.

[0132] Selectively enabling and disabling the synchronous rectifiers may include selectively enabling and disabling one side (or phase) of the synchronous rectifiers.

[0133] The synchronous rectifier may include at least one field effect transistor (FET).

[0134] The synchronous rectifier may include at least one of the following:

[0135] A rectifier element for rectifying the power signal into DC;

[0136] trigger circuit; and

[0137] A gate driver is electrically connected to the trigger circuit and the rectifier element.

[0138] The gate driver may be used to control the operation of the rectifier element via a trigger signal output by the trigger circuit.The gate driver may output a gate drive voltage or gate signal that is in phase with an input voltage received at the rectifier element.

[0139] The trigger circuit can ensure proper timing of the gate drive voltage or gate signal output by the gate driver.

[0140] 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 suitable for converting 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.

[0141] The gate driver can output a gate drive voltage or a gate signal to control the operation of the rectifier element. Specifically, the gate signal can control the operation of the amplifier by controlling the operation of the FET.

[0142] The trigger circuit may include:

[0143] The sampling circuit is used to sample the input signal.

[0144] The sampling circuit may be a voltage divider.

[0145] The trigger circuit may include:

[0146] A delay line is used to delay the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element.

[0147] The trigger circuit may include:

[0148] A comparator is configured to generate a clock signal by comparing a delayed signal output by the delay line with a DC voltage level.

[0149] The trigger circuit may include:

[0150] The RC delay circuit is used to delay the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element.

[0151] The RC delay circuit may include at least one resistor electrically connected to at least one capacitor.

[0152] The trigger circuit may include:

[0153] A comparator is configured to generate a clock signal by comparing a delayed signal output by the RC delay circuit with a DC voltage level.

[0154] The synchronous rectifier may further include an auxiliary DC / DC converter for powering at least one of the trigger circuit and the gate driver. In other words, the synchronous rectifier may include a power supply for powering at least one of the trigger circuit and the gate driver. The power supply may be powered by power received at the receiver (e.g., power received from the transmitter via wireless power transfer).

[0155] The auxiliary DC / DC converter may be electrically connected to a low dropout (LDO) regulator.

[0156] Modifying the operation of a synchronous rectifier may include:

[0157] Controlling the 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.

[0158] Controlling the operation of the trigger circuit may include:

[0159] Controlling operation of a 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.

[0160] Controlling the operation of the auxiliary DC / DC converter may include:

[0161] The auxiliary DC / DC converter can be configured to selectively enable and disable operation of the auxiliary DC / DC converter to selectively power the trigger circuit and the gate driver. Selectively enabling / disabling the auxiliary DC / DC converter can include controlling power supplied to the auxiliary DC / DC converter. The auxiliary DC / DC converter can include an enable pin. Selectively enabling the auxiliary DC / DC converter can include selectively enabling the auxiliary DC / DC converter via the enable pin.

[0162] Detecting parameter changes can include:

[0163] Detecting a voltage or current waveform at the transmitter. The voltage or current waveform may be detected at certain nodes of the transmitter. The voltage waveform may be detected at the output stage of the transmitter. The current waveform may be detected at the input of an inverter of the transmitter.

[0164] Determining the data being transferred may include:

[0165] The detected voltage or current waveform is processed to determine the communicated data.

[0166] Processing the detected voltage or current waveform may include:

[0167] Filtering voltage or current waveforms; and

[0168] generating a logic level based on the filtered voltage or current waveform; and

[0169] Data is decoded based on the generated logic levels.

[0170] Logic levels can reflect changes in voltage or current waveforms. For example, a change from high voltage to low voltage can represent a 1-to-0 data transmission, and a change from low voltage to high voltage can represent a 0-to-1 data transmission.

[0171] Decoding the data involves:

[0172] Determine the time intervals between logic levels; and

[0173] Decodes data based on time intervals.

[0174] According to another aspect, a method of detecting a medium between a transmitter of a wireless power transfer system and a receiver of the wireless power transfer system, the receiver being adapted to extract power from a field generated by the transmitter, is provided.

[0175] The method may include:

[0176] detecting parameters at a transmitter of the wireless power transfer system and / or a receiver of the wireless power transfer system; and

[0177] The medium between the transmitter and receiver is detected based on the parameters.

[0178] Media may include:

[0179] Building structures, building materials (such as wood and concrete, walls, doors, air, plastic, water, polymers), and windows. The windows can be made of glass. The transmitter and receiver can be positioned on opposite sides of the medium. The medium can separate the transmitter and receiver so that the medium defines a volume between the transmitter and receiver.

[0180] 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 a transmitter.

[0181] The parameter may include reactance at a receiver of the wireless power transmission system. The reactance may be at a receiver resonator of the receiver. The parameter may include the phase of the impedance at the receiver. In particular, the parameter may include the phase of the impedance at the receiver resonator or receiving element of the receiver. The phase of the impedance may be a phase angle. The phase angle may be correlated with reactance, as a large phase angle (e.g., a phase angle exceeding a predetermined threshold) may indicate a large reactance. Similarly, a small phase angle (e.g., a phase angle less than a predetermined threshold) may indicate a small reactance.

[0182] The parameter may include power received at the receiver. The power received at the receiver may include power to a load that is (possibly indirectly) electrically connected to the receiving element, or power output by a rectifier element at the receiver.

[0183] The parameter may include temperature data, such as the temperature of a receiving component, a receiver resonator, or a rectifier component. The method may also include controlling the output voltage of a transmitter converter (e.g., a DC / DC converter) based on the detected temperature data. Controlling the output voltage may include reducing or increasing the output voltage based on the temperature data. For example, if the temperature data indicates that the temperature of certain receiving components (e.g., a rectifier component) is above a threshold, the output voltage may be reduced. This may reduce the temperature of the receiving component.

[0184] The parameter may include the magnitude of the impedance at a receiver resonator or a receiving element of the receiver.

[0185] 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.

[0186] Detecting the medium may include detecting the presence of metal between the transmitter and the receiver.

[0187] Detecting the medium may include detecting the medium between the transmitter and the receiver based on the parameter reaching a threshold level. The threshold level may indicate a specific medium. For example, a threshold between a known range may indicate the presence of metal between the transmitter and the receiver.

[0188] According to another aspect, there is provided a controller configured to control at least one of an inverter of a transmitter of a wireless power transmission system, a converter of the transmitter, a transmitter and a receiver of the wireless power transmission system to perform any of the described methods.

[0189] According to another aspect, there is provided a controller for wirelessly transferring power through a medium according to any of the described methods.

[0190] The controller described may include an MCU.

[0191] The converter may include a DC / DC converter.

[0192] The described controller may also be used to transmit signals between a receiver of a wireless power transfer system and a transmitter of the wireless power transfer system, the receiver including a synchronous rectifier.

[0193] The controller may be adapted to modify the operation of the synchronous rectifier to change a parameter detectable at the transmitter.

[0194] The controller may be adapted to switch the synchronous rectifier between synchronous operation and non-synchronous operation.

[0195] The controller may be adapted to selectively enable and disable the synchronous rectifier.

[0196] Selectively enabling and disabling the synchronous rectifiers may include enabling and disabling synchronous operation of the synchronous rectifiers. Modifying the operation of the synchronous rectifiers may include switching the operation of the synchronous operation. The time between selectively enabling / disabling or switching operations may be varied to transfer data from the receiver to the transmitter.

[0197] A controller may be electrically connected to the synchronous rectifier.

[0198] The controller may be electrically connected to at least one of the following:

[0199] a trigger circuit for a synchronous rectifier; and

[0200] A gate driver for the synchronous rectifier is electrically connected to the trigger circuit and the rectifier element of the synchronous rectifier.

[0201] The controller may be adapted to control the operation of a comparator of the trigger circuit. Controlling the operation of the comparator may include selectively enabling power to the comparator. The comparator may include a comparator circuit.

[0202] The controller can be electrically connected to:

[0203] An auxiliary DC / DC converter of the synchronous rectifier is used to power at least one of the trigger circuit and the gate driver.

[0204] 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.

[0205] 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 (e.g., power received from the transmitter via wireless power transmission).

[0206] The power supply may include an auxiliary DC / DC converter.

[0207] The controller can be powered by an LDO regulator.

[0208] According to another aspect, a method for wireless power transfer through a medium is provided. The medium may be between a transmitter and a receiver of a wireless power transfer system. The transmitter may generate a field at least partially within the medium. The receiver may extract power from the generated field. The transmitter and receiver may be separated by the medium, such that the transmitter and receiver are on opposite sides of the medium.

[0209] The method may include:

[0210] detecting parameters at a receiver of a wireless power transfer system;

[0211] transmitting the detected parameters to a transmitter of the wireless power transmission system;

[0212] controlling an input voltage of an inverter of the transmitter based on the detected parameter; and

[0213] A field is generated for wirelessly transferring power through a medium to a receiver of a wireless power transfer system.

[0214] Detecting may include detecting via a voltage detector of a receiver of the wireless power transfer system.

[0215] The parameter may include a rectified voltage at the receiver. The parameter 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 suitable for converting 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.

[0216] The communication may include communicating via a controller of the receiver. The controller may include one or more MCUs.

[0217] The control may include controlling via a controller of the transmitter. The controller may include one or more MCUs. The control 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 configured to convert a received DC voltage signal to a desired voltage level. The received DC voltage may be derived from a power supply of the transmitter.

[0218] The generating may include generating via a transmit resonator of the transmitter. The transmit resonator may be electrically connected to the inverter. The strength of the generated field may be based on the output voltage of the converter and / or the input voltage of the inverter.

[0219] According to another aspect, a non-transitory computer-readable medium comprising computer-executable code for execution on a processor to perform any of the described methods is provided.

[0220] According to another aspect, a transmitter of a wireless power transmission system is provided, the transmitter being configured to wirelessly transmit power to a receiver of the wireless power transmission system through a medium.

[0221] Transmitters may include:

[0222] a transmitting resonator for wirelessly transmitting power to a receiver of the wireless power transmission system through a medium;

[0223] an inverter electrically connected to the transmission resonator; and

[0224] A controller is configured to control an input voltage of the inverter based on the detected parameter.

[0225] The controller described may include an MCU.

[0226] The transmitter may also include:

[0227] Sensors are used to detect parameters at the transmitter and / or receiver.

[0228] 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 a transmitter.

[0229] The transmitter may also include:

[0230] The communication module is configured to receive parameters from a receiver of the wireless power transmission system.

[0231] The communication module may include a controller for detecting parameter changes at the transmitter based on modifications to the operation of the synchronous rectifiers of the receiver. The communication module may receive the parameters via a communication protocol including Bluetooth, Wi-Fi, 5G, or other suitable communication protocols.

[0232] The controller may also be adapted to determine data to be transmitted from the receiver to the transmitter based on the parameter change.

[0233] The controller may also include:

[0234] A detector is used to detect the voltage and / or current waveform at the transmitter.

[0235] The detector may also include:

[0236] A demodulator is adapted to demodulate the voltage and / or current waveform at the transmitter.

[0237] Detectors may include:

[0238] A filter is adapted to filter the demodulated voltage and / or current.

[0239] The detector can be adapted to:

[0240] generating logic levels based on the filtered voltage and / or current; and

[0241] Data is decoded based on the generated logic levels.

[0242] The detector can be adapted to:

[0243] Determine the time intervals between logic levels; and

[0244] The data is decoded based on the time interval.

[0245] The controller may also include a power supply for supplying power to the controller.

[0246] The power supply may include an auxiliary DC / DC converter.

[0247] The controller can be powered by an LDO regulator.

[0248] The controller may also include:

[0249] The scaling unit is used to reduce the amplitude of the detected voltage or current waveform. Reducing the amplitude of the waveform can simplify waveform processing.

[0250] The controller may also include:

[0251] A peak detector is used to detect the peak value in the detected voltage or current waveform.

[0252] The controller may also include:

[0253] Signal conditioner.

[0254] The signal conditioner may be adapted to amplify the detected voltage or current waveform.

[0255] The signal conditioner may be adapted to compare the detected voltage or current waveform with a reference level (eg, a reference voltage or current level).The signal conditioner may be adapted to output a logic level signal, such as a 0 or a 1, based on the comparison.

[0256] The signal conditioner may comprise a comparator. The comparator may be adapted to perform the described comparison.

[0257] The controller may also include:

[0258] An encoder receives data and encodes the data into a time sequence. Thus, the data to be transmitted from the receiver to the transmitter can be encoded into a time sequence for synchronous and asynchronous operation of the synchronous rectifier. The data can be binary data.

[0259] The synchronous rectifier can switch between synchronous and non-synchronous operation based on a time sequence encoded by the encoder. Switching the synchronous rectifier according to the time sequence can cause a detectable parameter change at the transmitter, which can be demodulated or decoded into data, thereby transmitting the data from the receiver to the transmitter.

[0260] According to another aspect, there is provided a wireless power transmission system comprising:

[0261] a transmitter, the transmitter comprising a transmitter resonator and an inverter, the transmitter resonator being configured to wirelessly transmit power to a receiver of the wireless power transmission system through a medium, the inverter being electrically connected to the transmitter resonator;

[0262] a receiver comprising a receive resonator for wirelessly extracting power from the transmitter via electric and / or magnetic field coupling; and

[0263] A controller is configured to control an input voltage of the inverter based on the detected parameter.

[0264] The system may also include:

[0265] Sensors are used to detect parameters at the transmitter and / or receiver.

[0266] 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 a transmitter.

[0267] The receiver may also include:

[0268] Communication module for transferring parameters from receiver to transmitter.

[0269] The communication module may include a controller. The controller may include an MCU. The controller may be adapted to modify the operation of the synchronous rectifier to change a parameter detectable at the transmitter. The communication module may transmit the parameter via a communication protocol including Bluetooth, Wi-Fi, 5G, or other suitable communication protocols.

[0270] The controller may be adapted to switch the synchronous rectifier between synchronous operation and non-synchronous operation.

[0271] The controller may be adapted to selectively enable and disable the synchronous rectifier.

[0272] Selectively enabling and disabling the synchronous rectifiers may include enabling and disabling synchronous operation of the synchronous rectifiers. Modifying the operation of the synchronous rectifiers may include switching the operation of the synchronous operation. The time between selectively enabling / disabling or switching operations may be varied to transfer data from the receiver to the transmitter.

[0273] A controller may be electrically connected to the synchronous rectifier.

[0274] The controller may be electrically connected to at least one of the following:

[0275] a trigger circuit for a synchronous rectifier; and

[0276] A gate driver for the synchronous rectifier is electrically connected to the trigger circuit and the rectifier element of the synchronous rectifier.

[0277] The controller may be adapted to control the operation of a comparator of the trigger circuit. Controlling the operation of the comparator may include selectively enabling power to the comparator. The comparator may include a comparator circuit.

[0278] The controller can be electrically connected to:

[0279] An auxiliary DC / DC converter of the synchronous rectifier is used to power at least one of the trigger circuit and the gate driver.

[0280] 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.

[0281] 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 (e.g., power received from the transmitter via wireless power transmission).

[0282] The power supply may include an auxiliary DC / DC converter.

[0283] The controller can be powered by an LDO regulator.

[0284] The transmitter may also include:

[0285] The communication module is used to receive parameters from the receiver.

[0286] The communication module may further include a controller. The controller may include a microcontroller (MCU). The controller may be adapted to detect parameter changes at the transmitter based on modifications to the operation of the synchronous rectifier of the receiver. The communication module may receive the parameters via a communication protocol including Bluetooth, Wi-Fi, 5G, or other suitable communication protocols.

[0287] The controller may also be adapted to determine data to be transmitted from the receiver to the transmitter based on the parameter change.

[0288] The controller may also include:

[0289] A detector is used to detect the voltage and / or current waveform at the transmitter.

[0290] The detector may also include:

[0291] A demodulator is adapted to demodulate the voltage and / or current waveform at the transmitter.

[0292] Detectors may include:

[0293] A filter is adapted to filter the demodulated voltage and / or current.

[0294] The detector can be adapted to:

[0295] generating logic levels based on the filtered voltage and / or current; and

[0296] Data is decoded based on the generated logic levels.

[0297] The detector can be adapted to:

[0298] Determine the time intervals between logic levels; and

[0299] The data is decoded based on the time interval.

[0300] The controller may also include a power supply for supplying power to the controller.

[0301] The power supply may include an auxiliary DC / DC converter.

[0302] The controller can be powered by an LDO regulator.

[0303] The controller may also include:

[0304] The scaling unit is used to reduce the amplitude of the detected voltage or current waveform. Reducing the amplitude of the waveform can simplify waveform processing.

[0305] The controller may also include:

[0306] A peak detector is used to detect the peak value in the detected voltage or current waveform.

[0307] The controller may also include:

[0308] Signal conditioner.

[0309] The signal conditioner may be adapted to amplify the detected voltage or current waveform.

[0310] The signal conditioner may be adapted to compare the detected voltage or current waveform with a reference level (eg, a reference voltage or current level).The signal conditioner may be adapted to output a logic level signal, such as a 0 or a 1, based on the comparison.

[0311] The signal conditioner may comprise a comparator. The comparator may be adapted to perform the described comparison.

[0312] The controller may also include:

[0313] An encoder receives data and encodes the data into a time sequence. Thus, the data to be transmitted from the receiver to the transmitter can be encoded into a time sequence for synchronous and asynchronous operation of the synchronous rectifier. The data can be binary data.

[0314] The transmitter may also include:

[0315] The converter is electrically connected to the inverter. The converter may include a DC / DC converter.

[0316] The controller may be configured to control an output voltage of the converter based on the detected parameter.The output voltage of the converter may define an input voltage of the inverter.

[0317] According to another aspect, there is provided a computer readable medium comprising instructions which, when executed by a processor, perform any of the described methods.

[0318] Computer-readable media can be non-transitory. Computer-readable media can include storage media that do not contain propagating signals. Computer-readable media can 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.

[0319] The processor may have a single core processor or a multi-core processor constructed from a variety of materials such as silicon, polysilicon, high-K dielectric, copper, and the like.

[0320] According to yet another aspect, there is provided a computer program comprising instructions which, when executed by a processor, perform any of the described methods.

[0321] The present invention includes one or more corresponding aspects, embodiments or features that can exist alone or in various combinations, whether or not specifically described in combination or alone (including in the claims). It should be understood that features associated with a particular exemplary embodiment relating to a system can also be applicable to features specifically relating to an embodiment of a method of operation or use, and vice versa.

[0322] The foregoing summary is intended to be illustrative only and not limiting. BRIEF DESCRIPTION OF THE DRAWINGS

[0323] These and other aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0324] Figure 1 is a block diagram of a wireless power transfer system;

[0325] Figure 2 is another block diagram of a wireless power transfer system;

[0326] Figure 3 Separated by medium Figure 2 Block diagram of a transmitter and a receiver of a wireless power transmission system;

[0327] Figure 4 yes Figure 2 A block diagram of a receiver for a wireless power transmission system;

[0328] Figure 5 yes Figure 2 a block diagram of a portion of a circuit of a receiver;

[0329] Figure 6 yes Figure 2 a schematic diagram of a portion of a circuit of a receiver;

[0330] Figure 7 is a block diagram of a receiver of a wireless power transmission system according to an aspect of the present disclosure;

[0331] Figure 8 is a block diagram of a receiver of a wireless power transmission system according to an aspect of the present disclosure;

[0332] Figure 9 yes Figure 8 a schematic diagram of a portion of a receiver;

[0333] Figure 10 yes Figure 8 a schematic diagram of another portion of the receiver;

[0334] Figure 11 is a block diagram of a transmitter of a wireless power transmission system according to an aspect of the present disclosure;

[0335] Figure 12 yes Figure 11 a schematic diagram of a portion of a transmitter;

[0336] Figure 13 yes Figure 11 A block diagram of a detector of a transmitter;

[0337] Figure 14 is a flow chart of a method of wireless power transmission through a medium according to an aspect of the present disclosure;

[0338] Figure 15 is a graph of voltage and current waveforms of a transmitter according to one aspect of the present disclosure;

[0339] Figure 16 is a graph of voltage rise time of a transmitter according to an aspect of the present disclosure;

[0340] Figure 17 is a graph of voltage fall time of a transmitter according to an aspect of the present disclosure;

[0341] Figure 18 is a graph of current rise time of a transmitter according to an aspect of the present disclosure;

[0342] Figure 19 is a graph of current fall time of a transmitter according to an aspect of the present disclosure;

[0343] Figure 20 is a schematic diagram of a portion of a transmitter according to an aspect of the present disclosure; and

[0344] Figure 21 yes Figure 20 Block diagram of the transmitter's current demodulator. DETAILED DESCRIPTION

[0345] The foregoing summary of the invention and the detailed description of certain embodiments below will be better understood by reading in conjunction with the accompanying drawings. It should be understood that throughout the specification and the accompanying drawings, the same reference numerals are used to refer to the same elements. As used herein, elements or features cited in the singular and preceded by the word "one" or "an" should be understood to not necessarily exclude multiple elements or features. In addition, reference to "an example" or "an embodiment" is not intended to be interpreted as excluding the existence of other examples or embodiments that also include elements or features cited by this example or embodiment. In addition, unless explicitly stated otherwise, examples or embodiments that "include," "have," or "contain" one or more elements or features with a specific property may also include other elements or features that do not have this specific property. In addition, it should be understood that the terms "include," "have," and "contain" mean "including but not limited to," and the terms "include," "have," and "contain" have equivalent meanings.

[0346] As used herein, the term "and / or" may include any and all combinations of the associated one or more listed elements or features.

[0347] It should be understood that when an element or feature is referred to as being “on (another element or feature),” “attached” to another element or feature, “connected” to another element or feature, “coupled” to another element or feature, “contacting” another element or feature, etc., the element or feature can be directly on, directly attached to, directly connected to, directly coupled to, or directly contacting another element or feature, or intervening elements may also be present. In contrast, when an element or feature is referred to as, for example, being “directly on (another element or feature),” “directly attached” to, “directly connected” to, “directly coupled” to, or “directly contacting” another element or feature, there are no intervening elements or features present.

[0348] It should be understood that spatially relative terms, such as "below," "beneath," "lower," "above," "upper," "front," and "rear," may be used herein to facilitate describing the relationship of an element or feature depicted in the drawings to another element or feature. However, the spatially relative terms may refer to different orientations in use or operation in addition to the orientation depicted in the drawings.

[0349] Reference herein to an "example" means that one or more features, structures, elements, components, characteristics, and / or operational steps described in connection with the example are included in at least one embodiment and / or implementation of the subject matter of the present disclosure. Thus, throughout this disclosure, the phrases "an example," "another example," and similar language may, but do not necessarily, refer to the same example. Furthermore, subject matter representing any one example may, but does not necessarily, include subject matter representing any other example.

[0350] References herein to "configured" refer to the actual state of configuration that substantially relates the physical characteristics of an element or feature to the element or feature preceding the phrase "configured to."

[0351] Unless otherwise indicated, the terms "first," "second," etc. are used herein merely as labels and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Furthermore, 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).

[0352] As used herein, the terms "approximately" and "about" mean close to a specified amount and still perform a desired function or achieve a desired result. For example, the terms "approximately" and "about" may refer to a quantity being within less than 10%, less than 5%, less than 1%, less than 0.1%, or less than 0.01% of a specified amount.

[0353] Now go to Figure 1 , a wireless power transfer system, generally designated by the reference numeral 100, is shown. The wireless power transfer system 100 includes a transmitter 110 (including a power source 112 electrically connected to a transmitting element 116) and a receiver 120 (including a receiving element 124 electrically connected to a load 128). Power is transferred from the power source 112 to the transmitting element 116. Power is then transferred from the transmitting element 116 to the receiving element 124 via resonant or non-resonant electric or magnetic field coupling. Power is then transferred from the receiving element 124 to the load 128. The 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 capacitive coupling wireless power transfer system as described in applicant's U.S. Patent No. 9,653,948 B2, relevant portions of which are incorporated herein.

[0354] In the wireless power transfer system 100, power is transferred from the transmitting element 116 to the receiving element 124. The exemplary wireless power transfer system 100 comprises a high frequency inductive wireless power transfer system as described in US Patent Application No. 17 / 018,328, relevant portions of which are incorporated herein.

[0355] Now go to Figure 2, shows another embodiment of a wireless power transmission system, generally designated by reference numeral 200. Wireless power transmission system 200 includes a power source 212, a DC / DC converter 214, a circuit 216, and a transmitting element 222. Power source 212 is electrically connected to DC / DC converter 214. DC / DC converter 214 is electrically connected to circuit 216. Circuit 216 is electrically connected to transmitting element 222.

[0356] The power supply 212 is configured to generate an input power signal for transmitting power. In this embodiment, the input power signal is a direct current (DC) power signal.

[0357] The DC / DC converter 214 is used to convert the received DC voltage signal to a desired voltage level. The received DC voltage can come from the power supply 212. The system 200 shown includes the DC / DC converter 214, and those skilled in the art will appreciate that other configurations are possible. In another embodiment, there is no DC / DC converter.

[0358] In the arrangement shown, circuit 216 includes an inverter and an output stage. The output stage matches the output impedance of circuit 216 to the optimal impedance of wireless link 230 between the transmitter and receiver. The output stage also filters high-frequency harmonic components of the inverter.

[0359] The transmitting element 222 includes one or more inductive elements, i.e., inductors. The inductive elements may include one or more coils. The coils may include booster or shield coils, such as those described in applicant's U.S. patent application Ser. No. 17 / 193,539, the relevant portions of which are incorporated herein by reference.

[0360] In another arrangement, the transmitting element 222 includes one or more capacitive elements, such as capacitive electrodes. The capacitive electrodes can be elongated electrodes spaced laterally apart; however, those skilled in the art will appreciate that other configurations are possible, including but not limited to concentric, coplanar, circular, elliptical, disk-shaped, and other electrodes. Other suitable electrode configurations are described in Applicant's U.S. Patent No. 9,979,206 B2, the relevant portions of which are incorporated herein by reference. As those skilled in the art will appreciate, the transmitting element 222 can include a combination of inductive and capacitive elements.

[0361] Power supply 212 provides a DC input power signal to DC / DC converter 214, which converts the signal to a desired voltage level. The inverter of circuit 216 receives the converted DC power signal and inverts it to generate a magnetic field and / or electric field at transceiver element 222, thereby transmitting power via electric or magnetic field coupling. Specifically, transmitting element 222 generates a magnetic / electric field to transmit power to a receiver via magnetic / electric field coupling. Power supply 212, DC / DC converter 214, circuit 216, and transmitting element 222 may collectively form transmitter 210. As previously described, DC / DC converter 214 may not be present in transmitter 210.

[0362] Wireless power transmission system 200 further includes a load 228, a DC / DC converter 226, a circuit 224, and a receiving element 229. Load 228 is electrically connected to DC / DC converter 226. DC / DC converter 226 is electrically connected to circuit 224. Circuit 224 is electrically connected to receiving element 229.

[0363] In the arrangement shown, the load 228 is a DC load. The load 228 may be static or variable.

[0364] The DC / DC converter 226 is used to convert the received DC voltage signal to a desired voltage level. The received DC voltage can come from the circuit 224. Although the system 200 includes the DC / DC converter 226, it will be understood by those skilled in the art that other configurations are also possible. In another embodiment, there is no DC / DC converter 226.

[0365] Circuit 224 includes an input stage and a rectifier, such as a diode rectifier or a synchronous rectifier. The input stage is configured to ensure that the optimal impedance is presented to the receiving element 229 in the full power state of the wireless power transmission system 200. The input stage can also maintain the quasi-voltage source behavior of the receiving element 229, so that the output of the synchronous rectifier presents a stable DC voltage from no-load to full-load conditions.

[0366] The receiving element 229 includes one or more inductive elements, i.e., inductors. The receiving element 229 may include one or more coils. The coils may include booster or shield coils, such as those described in applicant's U.S. patent application Ser. No. 17 / 193,539, the relevant portions of which are incorporated herein by reference.

[0367] In another arrangement, the transmitting element 222 includes one or more capacitive elements, such as capacitive electrodes. The capacitive electrodes can be elongated electrodes spaced laterally apart; however, those skilled in the art will appreciate that other configurations are possible, including but not limited to concentric, coplanar, circular, elliptical, disk-shaped, and other electrodes. Other suitable electrode configurations are described in Applicant's U.S. Patent No. 9,979,206 B2, the relevant portions of which are incorporated herein by reference. As those skilled in the art will appreciate, the transmitting element 222 can include a combination of inductive and capacitive elements.

[0368] The transmitting element 222 and receiving element 229 of system 200 form a wireless link 230. Elements 222 and 229 are separated by a wireless gap. The wireless gap can be formed by the atmosphere (i.e., air) or by a physical medium (e.g., a wall, glass, liquid, wood, an insulator, etc.). Power is transferred from one element to another across wireless link 230 via resonant or non-resonant magnetic and / or electric field coupling (i.e., electrical or magnetic induction).

[0369] During operation, receiving element 229 extracts power from the magnetic and / or electric fields generated by transmitting element 222. Circuit 224 functions as a rectifier, such as a diode rectifier or synchronous rectifier, and rectifies the received power signal. DC / DC converter 226 converts the rectified power signal to the desired power level for reception by load 228. In this manner, receiving element 229 extracts the power transmitted by transmitting element 222 (transmitter 210), transferring the electric power to load 228 via magnetic / electric field coupling. Load 228, DC / DC converter 226, circuit 224, and receiving element 229 may collectively form receiver 220. As previously mentioned, DC / DC converter 226 may not be present in receiver 220.

[0370] Now go to Figure 3 , shows a transmitter 210 and a receiver 220 of the system 200. In the arrangement shown, 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 can define a separation distance between the transmitting element 222 and the receiving element 229.

[0371] Medium 232 can be at least partially in the form of an air gap, or can be at least partially a physical medium such as glass, wood, concrete, or other building materials. Wireless power transmission system 200 can be tuned for a specific medium 232 (e.g., the thickness of the medium or the material properties of the medium). Changing the characteristics of medium 232 (e.g., thickness) or completely changing the medium (e.g., introducing a different material into the space between transmitter 210 and receiver 220) can result in suboptimal wireless power transmission between transmitter 210 and receiver 220. Tuning of system 200 may be suboptimal for the new, altered medium 232 or new medium characteristics or parameters. Consequently, power transmission from transmitter 210 to receiver 220 may be suboptimal, e.g., with reduced average power transfer efficiency. Adjusting wireless power transmission to account for changes in medium 232 can correspondingly improve average power transfer efficiency. The present disclosure can provide such improved average power transfer efficiency.

[0372] For example, system 200 can wirelessly transmit electrical power through a medium 232 that is 15 mm thick. Medium 232 can be removed and replaced with one that is 30 mm thick, and power transmission will continue just as effectively as it did at 15 mm. Furthermore, medium 232 can have a dynamic thickness, meaning the thickness of the medium itself, and thus 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 15 mm. If the panes are further separated to 30 mm, power transmission will be maintained and continue just as effectively as at 15 mm, without any observable change in power transmission and without any external modifications required. In another example, transmitter 210 and receiver 220 can be repositioned relative to a portion of the medium, causing the separation distance between transmitter 210 and receiver 220 to change. System 200 self-optimizes based on the material and distance between transmitter 210 and receiver 220 defined by medium 232. Although the average power transfer efficiency may change when the medium 232 changes as described, the change (e.g., decrease) will not be as significant as in a conventional system where the inverter input voltage (DC / DC converter output voltage) is not modified in response to changes at the medium 232.

[0373] Wireless power transfer system 200 may include a high-frequency wireless power transfer system as described in the '328 application. A high-frequency wireless power transfer system is an inductive system. Those skilled in the art will appreciate that a high-frequency wireless power transfer system can be configured to transfer power via high-frequency magnetic inductive coupling or high-frequency capacitive coupling. In a magnetic inductive coupling system, the majority of power transfer occurs via a magnetic field. Little, if any, power is transferred via capacitance or resonant capacitance (electric field). In a capacitive coupling system, the majority of power transfer occurs via an electric field. Little, if any, power is transferred via magnetic induction or resonant magnetic induction.

[0374] The high-frequency wireless power transmission system is configured to transmit power via high-frequency magnetic field coupling. The transmitter 210 of the high-frequency wireless power transmission 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.

[0375] like Figure 3 As shown, transmitter 210 is positioned near medium 232. Transmitter 210 can be attached to medium 232. For example, transmitter 210 can be attached to a window of a building. Medium 232 can be a manufactured material and can be made of any type of material or combination of materials that is non-conductive or non-magnetic, such as wood, glass, stone, brick, concrete, plastic, except for materials or combinations of materials that would prematurely terminate the field (i.e., act as a shield). For example, a medium comprising walls covered with foil-backed insulation can terminate the generated field and act as a shield, thereby preventing wireless power transfer between transmitter 210 and receiver 220.

[0376] However, a medium 232 composed of unshielded material with fragments of partially shielded material may still allow wireless power transfer through the fragments. For example, a medium comprising a wall constructed of wood, insulation, vinyl siding (with a small number of embedded nails / staples or other metal materials) may not terminate the generated field and still allow wireless power transfer between transmitter 210 and receiver 220.

[0377] Furthermore, medium 232 may include one or more coatings, such as a coating on glass. For example, medium 232 may include glass with a metal oxide coating, such as silver (Ag, Ag2, or Ag3). The coating may not prevent wireless power transmission through the glass because the coating has an extremely thin skin depth. Although these coatings are typically conductive, the coating thickness is typically on the order of tens of nanometers or less. Although the coating may be conductive, the thickness is small compared to the wavelength of the wireless power system's operating frequency (the layer thickness is small compared to the skin depth at the system's operating frequency). Therefore, the field generated by a transmitter (e.g., a transmitting element) is able to penetrate the coating to be received by a receiver (e.g., a receiving element). While some power may be lost due to the presence of the coating, this is typically minimal. The amount of power dissipated in the coating may depend on the coating material, the layer thickness, and the system's operating frequency.

[0378] Furthermore, medium 232 may include a housing or frame, such as a metal window housing. Similarly, even if the transmitter and receiver are positioned on opposite sides of medium 232 near a corner of the housing or frame, this generally does not terminate power transfer. Likewise, power may be dissipated in the housing or frame, thereby reducing power transfer efficiency. The amount of power dissipated may depend on the housing or frame material, thickness, and system operating frequency.

[0379] The receiver 220 is located on the opposite side of the medium 232, such that the medium 232 is directly between the transmitter 210 and the receiver 220. Thus, the transmitter 210 and the receiver 220 can be coplanar, i.e., in the same plane through the medium. One skilled in the art will recognize that more than one transmitter 210 and receiver 220 are possible.

[0380] In this embodiment, the transmitter 210 includes the described transmitting element 222, which may take the form of an inductive coil or inductor, and the receiver 220 includes the described receiving element 229, which may take the form of an inductive coil or inductor. Those skilled in the art will recognize that more than one transmitting element 222 and / or receiving element 229 is possible.

[0381] The transmitting element 222 may operate in a current mode output (constant current output). In the current mode output, the transmitter 210 is configured to generate a magnetic field without requiring the receiver 220 to be present in the vicinity of the transmitter 210.

[0382] Generally speaking, a current-mode output high-frequency wireless power transmission system differs from a voltage-mode output (constant voltage output) high-frequency wireless power transmission system in that the voltage-mode output transmitter 210 cannot generate and maintain a magnetic field without the receiver 220 present in the vicinity of the transmitter 210. If the receiver 220 is not present in the voltage-mode output high-frequency wireless power transmission system, the transmitter 210 will essentially operate in a short-circuit condition and, therefore, cannot maintain the generation of a magnetic field.

[0383] 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 should be optimally aligned. Optimally aligning transmitter 210 and receiver 220 may be problematic if material 230 is opaque or if it completely blocks viewing of the location of transmitter 210, receiver 220, or both.

[0384] In optimal alignment of receiver 220 with transmitter 210, receiving element 229 is optimally aligned with transmitting element 222. Transmitter 210 and receiver 220 may be optimally aligned according to the methods and apparatus described in applicant's U.S. Patent Application No. 17 / 083,735, the relevant portions of which are incorporated herein.

[0385] Now go to Figure 4 , which shows the receiver 220 of the system 200 in more detail. In the arrangement shown, 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.

[0386] Receiver element 229 is electrically connected to input stage 250 and trigger circuit 252. 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. Receiver element 229 can extract power from the transmitter via non-resonant or resonant magnetic or electric field coupling. Therefore, receiver element 229 includes one or more receive coils (i.e., inductors) or one or more capacitive electrodes. The corresponding transmitters each include a corresponding transmit coil (i.e., inductor) or capacitive electrode.

[0387] The receiving element 229 extracts power from the transmitter and thus outputs an input voltage or signal Vin corresponding to the extracted power or signal.

[0388] Input stage 250 is electrically connected to rectifier element 254, receiving element 229, and trigger circuit 252. Input stage 250 is adapted to perform any combination of three functions. In particular, input stage 250 is used to transform the impedance presented by rectifier element 254 under nominal load into an optimal load impedance for receiving element 229. Input stage 250 is used to reduce the harmonic content generated by the nonlinear behavior of rectifier element 254, enabling receiver 220, and thus the wireless power system of which receiver 220 forms a part, to meet international product requirements related to electromagnetic compatibility (EMC). Input stage 250 is used to ensure that the current input to rectifier element 254 is approximately sinusoidal.

[0389] In this embodiment, the input stage 250 includes a matching network or circuit. A variety of matching networks are possible. In this embodiment, the matching network takes the form of a two-stage impedance inverter. The two-stage impedance inverter is electrically connected to the receiving element 229. The input stage 250 may also include additional filtering in series with the rectifier element 254. The use of a two-stage impedance inverter topology can advantageously ensure that the rectifier element 254 is driven by a quasi-constant voltage source. Although a two-stage impedance inverter is described, it will be understood by those skilled in the art that the matching network may take the form of a single-stage impedance inverter.

[0390] The input stage 250 is configured to ensure that the optimal impedance is presented to the receiving element 229 in the full power state of the wireless power transmission system 200. The input stage can also maintain the quasi-voltage source characteristic of the receiving element 229, so that the output of the rectifier presents a stable DC voltage from no-load to full-load conditions.

[0391] Rectifier element 254 is electrically connected to input stage 254 , main receiver DC / DC converter 226 (ie, main receiver DC / DC converter), and auxiliary DC / DC converter 258 .

[0392] Rectifier element 254 includes an amplifier. The amplifier is a Class E amplifier. The amplifier includes a gate driver 256 and a main switch. Gate driver 256 drives the amplifier's main switch. In this embodiment, the main switch includes an n-type MOSFET 260. Although an n-type MOSFET 260 is shown, those skilled in the art will appreciate that other FETs and switching devices may be used.

[0393] DC / DC converter 226 is electrically connected to rectifier element 254, auxiliary DC / DC converter 258, and load 228, such as a DC load. Main receiver DC / DC converter 226 is configured to receive a DC power signal Vrect output from rectifier element 254. DC / DC converter 226 connects rectifier element 254 to load 228. DC / DC converter 226 is configured to convert the received DC power signal. The converted DC power signal is output from DC / DC converter 226 to load 228.

[0394] An auxiliary DC / DC converter 258 is also electrically connected to the input of the main 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 element 254. The auxiliary DC / DC converter 258 is used to convert the Vrect output by the rectifier element 254 to an auxiliary voltage Vaux range, for example, in the 5V range, to power the trigger circuit 252 and the gate driver 256. The auxiliary supply voltage or signal Vaux powers the trigger circuit 252 and the gate driver 256. Until the auxiliary DC / DC converter 258 can regulate, the FET 260 of the rectifier element 254 is turned off, and the rectifier element 254 functions as a passive (diode) rectifier. In this embodiment, the auxiliary DC / DC converter 258 comprises a low-power buck converter.

[0395] 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, such as controlling the switching of the FET 260 of the rectifier element 254.

[0396] The trigger circuit 252 is electrically connected to the rectifier element 254. The trigger circuit 252 is used to synchronize wireless power transmission. The trigger circuit 252 is also electrically connected to the receiving element 229 and the input stage 250. To address the challenge of non-negligible propagation delay from the gate driver 256 and the trigger circuit 252, the trigger circuit 252 is designed so that the trigger circuit 252 further delays the output signal Vtrig to ensure that Vgate is synchronized with Vin.

[0397] The 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 can be variable. As will be understood by those skilled in the art, if DC conversion is not required, the load 228 can be directly connected to the rectifier element 254 and receive Vrect.

[0398] The gate signal Vgate controls the flow of current between the source and drain of FET 260, thereby controlling the input signal Vin received at receiving element 229. When the gate signal is in phase with the input signal, FET 260 operates as a class E inverter. Class E inverters typically operate at high efficiency, resulting in a high efficiency rectifier.

[0399] Receiver 220 also includes a voltage detector 390 electrically connected to microcontroller 320. Voltage detector 390 detects the rectified voltage Vrect at the output of rectifier element 254. The detected rectified voltage signal is then transmitted to microcontroller 320, which transmits the rectified voltage signal to transmitter 210. Microcontroller 320 may include such a communication module for transmitting the detected parameter (i.e., the rectified voltage signal) to transmitter 210. The communication module may communicate via a communication protocol including Bluetooth, Wi-Fi, or any other suitable communication protocol.

[0400] 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 one or both of input stage 250 and DC / DC converter 226.

[0401] Now go to Figure 5 , a block diagram of a portion of circuit 224. Specifically, a block diagram of trigger circuit 252 and gate driver 256 is shown. Figure 4 As shown, the input voltage or signal Vin is sampled by sampling circuit 260 and fed 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 fed to comparator circuit 264. Comparator circuit 264 generates a clock signal by comparing the delayed signal (Vd) output by delay line 262 with a DC level.

[0402] The resulting trigger voltage (Vtrig) is fed to the gate driver 256. The gate driver 256 converts the trigger voltage into a suitable waveform (Vgate) for driving the FET 260 of the rectifier element 254. Both the comparator circuit 264 and the gate driver 256 have propagation delays in the nanosecond range, which is significant when dealing with switching cycles of approximately 73.7ns (for an operating frequency of 13.56 MHz) or 36.9ns (for an operating frequency of 27.12 MHz). The sampling circuit 260, delay line 262, and comparator circuit 264 form the trigger circuit 252. These components are designed to ensure that Vgate is synchronized with Vin.

[0403] Now go to Figure 6 , shows a schematic diagram of another portion of the circuit 224. The schematic diagram shows an exemplary arrangement of the comparator circuit 264 and the gate driver 256. As previously described, the comparator circuit 264 generates the clock signal by comparing the delayed signal (Vd) output by the delay line 262 with the DC level.

[0404] like Figure 6 As shown, comparator circuit 264 includes a comparator 280 (A1) powered by an auxiliary supply having an auxiliary supply voltage (Vaux). The input of comparator 280 is biased to approximately half of Vaux. For the positive comparator input (V+), this is achieved using two equal-valued resistors 282 and 284, each having a resistance of R2. The negative comparator input (V-) is achieved using two equal-valued resistors 286 and 288, each having a resistance of R1.

[0405] The delayed voltage signal (Vd) output by delay line 262 is coupled to the negative comparator input (V-) via a DC blocking capacitor 290 having a capacitance (Cb). This causes the trigger voltage (Vtrig) to be inverted (180° out of phase) relative to the delayed voltage signal (Vd). This effectively accounts for half of the switching period in terms of the total delay required to ensure that Vgate is in phase with Vin, thereby reducing the burden on delay line 262.

[0406] In operation, the rectified voltage Vrect is detected by voltage detector 390. The detected rectified voltage Vrect is then transmitted by receiver microcontroller 320 to transmitter 210. Transmitter 210 then controls the output voltage of DC / DC converter 214, i.e., the input voltage of inverter 216, based on the transmitted rectified voltage, as will be described. The output voltage (i.e., the input voltage of inverter 216) determines the strength of the magnetic / electric field generated by transmitting element 222. Therefore, the field strength can be varied based on the rectified voltage at receiver 220.

[0407] If the properties or parameters of the medium 232 between receiver 220 and transmitter 210 change, the rectified voltage Vrect is affected accordingly. For example, if system 200 is tuned for a medium having a specific thickness (i.e., a specific separation distance between transmitter 210 and receiver 220), using system 200 on a medium having a different thickness may result in reduced average transmitted power and reduced average power transfer efficiency. This may require retuning system 200. However, as a result of the thickness change, the rectified voltage Vrect is affected. When the rectified voltage Vrect is detected by voltage detector 390 and transmitted to transmitter 210 by receiver microcontroller 330, transmitter 210 can modify the field strength by appropriately changing the output voltage of DC / DC converter 214. This increases average power transfer and average power transfer efficiency, and optimizes power transfer between transmitter 210 and receiver 220. When the field strength is altered to account for changes in medium 232, power losses at receiver 220 and / or transmitter 210 can be reduced, thereby improving (e.g., increasing) the average power transferred and / or average power transfer efficiency.

[0408] Specifically, the output voltage of DC / DC converter 214 can change from a first voltage level to a second voltage based on the rectified voltage. A voltage detector can monitor rectified voltage Vrect over a period of time, and if rectified voltage Vrect changes significantly enough within a sufficiently short period of time, controller 320 transmits the new rectified voltage Vrect to transmitter 210 to change the output voltage to the second level. For example, if rectified voltage Vrect drops by 4V within 1 second, controller 320 at receiver 210 or the controller at the transmitter can decide to increase the output voltage of DC / DC converter 214 (input voltage of inverter 216). If rectified voltage Vrect rises by a similar amount within a similar time frame, the controller at the transmitter can decide to control DC / DC converter 214 to decrease its output voltage (input voltage of inverter 216).

[0409] The controller at the transmitter makes this decision 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, meaning that the separation distance has decreased and the medium 232 has a reduced thickness or width. Alternatively, if the rectified voltage is lower than expected, it may indicate that the receiver 220 is further away from the transmitter 210 than expected. The expected rectified voltage may be the rectified voltage at which the receiver 220 is currently operating. Due to variations in the medium (such as composition) other than distance, the rectified voltage may be higher than expected. For example, if the system 200 is operating with a medium consisting of glass but is then moved to operate with a medium consisting of wood, the rectified voltage may decrease.

[0410] Once the controller at transmitter 210 receives the rectified voltage from receiver 220 (i.e., from receiver controller 230), the controller at 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.

[0411] For example, the initial input voltage may be 10V. This voltage is used to generate the field at transmitting element 224. The rectified voltage at receiver 220 (which is related to the power extracted from the generated field) is transmitted to transmitter 210. The controller at transmitter 210 then makes the decision whether to increase or decrease the input voltage. If the rectified voltage Vrect is within an acceptable range (determined experimentally), the decision may be to switch to a higher inverter 216 input voltage. If the rectified voltage Vrect is too high or too low, the decision may be to shut down / restart optimization system 200. Shutting down system 200 may mean reducing the input voltage to 0V, so that no field is generated.

[0412] If the rectified voltage Vrect is too high, the receiver 220 may be too close to the transmitter 210. The high rectified voltage Vrect at the receiver 220 may damage the electrical components at the receiver, such as diodes. Therefore, the input voltage must be kept low to prevent damage that negatively affects the switching node tuning at the receiver.

[0413] If the rectified voltage Vrect is too low, the receiver 220 may be too far from the transmitter 210. In this case, not enough power may be extracted to power the load 228 of the receiver 220, or the current into the rectifier elements of the receiver 220 may be too high (because of the low voltage), which may result in excessive heating at the receiver or unstable power transmission.

[0414] In addition, the controller at transmitter 210 can increase the input voltage based on the ratio between the input voltage and the rectified voltage. For example, if the input voltage is only 5V, a rectified voltage of 50V may indicate that receiver 220 is too close to transmitter 210. However, if the input voltage is 20V, a rectified voltage of 50V may be acceptable.

[0415] While the controller has been described as being located at the controller, in an alternative arrangement, the controller is located at the receiver. The controller at the receiver sends a signal to the transmitter 210 to increase or decrease the inverter 216 input voltage (and the DC / DC converter 214 output voltage) based on the rectified voltage. All described decisions are made by the controller at the receiver, which then simply sends a control signal to the transmitter 210.

[0416] Although receiver 220 has been described as including circuit 224 acting as a synchronous rectifier, those skilled in the art will appreciate that other configurations are possible. For example, circuit 224 can operate as a non-synchronous rectifier as previously described. In this arrangement, voltage detector 390 detects the rectified voltage Vrect, and this signal is transmitted to receiver controller 320 for transmission to transmitter 210, as described. Furthermore, voltage detector 390 can be eliminated. In this arrangement, rectified voltage Vrect is fed directly to the input of receiver microcontroller 330, which transmits the rectified voltage value to transmitter 210.

[0417] While the system 200 described can transfer power wirelessly, it may be desirable to send data from the receiver 220 to the transmitter 210. For example, it may be desirable to send data during operation of the wireless power transfer system 200 to transmit relevant data regarding the operating conditions of the receiver 220, such as DC voltage, current, temperature, and customer data (e.g., battery charge). The transmitter 210 can then use this data to make decisions regarding the authentication, protection, and operation of the system 200. Additionally, customer data can be sent from the receiver 220 to the transmitter 210, which can then be transmitted to an end user using common communication methods (e.g., Wi-Fi, Ethernet, Bluetooth, or USB).

[0418] To transmit data from a receiver to a transmitter in some wireless power transfer systems, a dummy load is introduced at the receiver to change the load conditions. The dummy load (e.g., a resistor) is connected in series via a switch at the output of the receiver's rectifier element. By turning the switch on and off, the system's load conditions are altered, and this change can be detected and demodulated at the transmitter to receive data from the receiver.

[0419] This approach has several drawbacks. For example, the baud rate (i.e., 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, however, it will increase the power dissipation in the dummy load resistor, causing component heating. Furthermore, reducing the value of the capacitor at the output of the rectifier element (i.e., the input capacitor of the receiver's DC / DC converter) may lead to unstable operation of the wireless power transmission system.

[0420] Other wireless power transfer systems incorporate capacitors at the switching nodes of the rectifier elements, rather than a pseudo-resistive load at the output of the rectifier elements. This technique can be effective for passive rectifier elements, but for synchronous rectifier elements, such as those described in circuit 226, turning off the capacitors can detune the zero voltage switching (ZVS) of the rectifier elements. Detuning the ZVS can reduce the efficiency of the rectifier elements, resulting in an overall reduction in the system's power transfer.

[0421] As described, the receiver microcontroller 330 can transmit the rectified voltage Vrect using a known communication protocol. However, other methods of transmitting the rectified voltage Vrect are possible. According to the present disclosure, a method and controller for communicating between a receiver of a wireless power transmission system and a transmitter of the wireless power transmission system are provided, the receiver including a synchronous rectifier.

[0422] Now go to Figure 7 , shows a receiver 300 according to one aspect of the present disclosure. Receiver 300 includes a receiving 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., a main receiver DC / DC converter), a low dropout (LDO) regulator 318, a microcontroller 320, and a load 322.

[0423] Receiver element 302 is electrically connected to input stage 304 and trigger circuit 306. Unless otherwise noted, receiver element 302 is identical to receiver element 229. 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.

[0424] Input stage 304 is electrically connected to rectifier element 308, trigger circuit 306, and receiving element 302. Input stage 304 is identical to input stage 250 unless otherwise noted.

[0425] The rectifier element 308 is electrically connected to the input stage 304, the trigger circuit 306, the auxiliary DC / DC converter 314, the DC / DC converter 316, the LDO regulator 318, and the microcontroller 320. Unless otherwise noted, the rectifier element 308 is identical to the rectifier element 254. In the arrangement shown, the gate driver 310 of the rectifier element 308 is electrically connected to the microcontroller 320 so that the microcontroller 320 can control the operation of the gate driver 310, as will be described.

[0426] The trigger circuit 306 is electrically connected to the rectifier element 308, the input stage 304, the receiving element 302, the auxiliary DC / DC converter 314, and the microcontroller 320. Unless otherwise noted, the trigger circuit 306 is identical to the trigger circuit 252. In the arrangement shown, the microcontroller 320 can control the operation of the trigger circuit 306, as will be described.

[0427] 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. Unless otherwise noted, auxiliary DC / DC converter 314 is identical to auxiliary DC / DC converter 258. In the arrangement shown, microcontroller 320 can control the operation of auxiliary DC / DC converter 314, as will be described.

[0428] DC / DC converter 316 is electrically connected to LDO regulator 318, auxiliary DC / DC converter 314, and rectifier element 308. DC converter 316 is identical to DC / DC converter 226 unless otherwise noted.

[0429] Load 322 is electrically connected to DC / DC converter 316. Load 322 is identical to load 228 unless otherwise noted.

[0430] An 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 provide power to the microcontroller 320.

[0431] The receiver 300 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 308. The detected rectified voltage signal is then transmitted to the microcontroller 320, which transmits the rectified voltage signal to the transmitter 210.

[0432] In particular, microcontroller 320 is adapted to selectively modify the operation of components of receiver 300. Specifically, microcontroller 320 is adapted to modify the operation of synchronous rectifiers (e.g., rectifier element 308, trigger circuit 306, and auxiliary DC / DC converter 314) of receiver 300. Microcontroller 320 is adapted to selectively enable and disable the synchronous rectifiers to achieve parameters detectable at the transmitter. Microcontroller 320 can selectively enable and disable the synchronous rectifiers based on a modulation scheme to transmit data to the transmitter. Parameter changes can be detected and demodulated based on known demodulation schemes to determine data transmitted from receiver 300 to a transmitter for wireless power transmission to receiver 300. Microcontroller 320 can operate using a modulation scheme known to the transmitter. Alternatively, microcontroller 320 can communicate the modulation scheme to the transmitter using known communication methods as described. In this manner, microcontroller 320 transmits a rectified voltage signal to a transmitter, such as transmitter 210.

[0433] Microcontroller 320 receives input data for transmission to the transmitter. Alternatively, microcontroller 320 may generate its own data for transmission to the transmitter. For example, microcontroller 320 may include a timer. Microcontroller 320 may be adapted to transmit data (i.e., timer data) from the timer to the transmitter. Thus, a reference to data transmitted to the transmitter may include data received by microcontroller 320 for transmission and / or data generated by microcontroller 320 for transmission.

[0434] In the illustrated arrangement, the microcontroller 320 receives input data from a voltage detector 390, which detects a rectified voltage Vrect. As will be appreciated by those skilled in the art, the microcontroller 320 can receive the rectified voltage Vrect as a direct input for communicating with the transmitter. Alternatively or additionally, the microcontroller 320 can receive changes in the rectified voltage. These changes in the rectified voltage can then be communicated to the transmitter.

[0435] 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). Specifically, the microcontroller 320 controls the amount of time the synchronous rectifier is enabled and disabled, thereby encoding the data for transmission. The timing can be controlled according to the modulation scheme.

[0436] In the arrangement shown, the microcontroller 320 includes a plurality of outputs, such as general purpose inputs / outputs, that control the operation of the auxiliary DC / DC converter 314, which provides power to the gate driver 310 and the trigger circuit 306, a comparator (e.g., comparator circuit 264) of the trigger circuit 306, and the gate driver 310. Those skilled in the art will appreciate that the microcontroller 320 may be electrically connected to only one of these components in order to switch the operation of the synchronous rectifier.

[0437] Microcontroller 320 is adapted to disable operation of any of these components, thereby placing the synchronous rectifier in an unloaded state. Due to the junction capacitance of the diodes connected in parallel with the main switches of the class E synchronous rectifiers of rectifier element 308, the impedance presented to receiving element 302 will be different compared to synchronous operation. The duty cycle of the diodes at the switch nodes of rectifier element 308 is close to 100%. This results in a sharp change in the impedance seen by receiving element 302, and therefore a sharp change in the impedance seen by the transmitter wirelessly transmitting power to receiver 300. This sharp change in the transmitter's output impedance results in a transient change in the waveform at the transmitter, which can be decoded to determine the data transmitted from receiver 300 to the transmitter, such as the rectified voltage.

[0438] Although the receivers 220, 300 have been described as including circuits that function as synchronous rectifiers, those skilled in the art will appreciate that other configurations are possible. For example, the rectifiers may be non-synchronous. In particular, the non-synchronous rectifiers may include diode rectifiers. Figure 8 , shows a block diagram of another arrangement of a receiver. In this arrangement, unless otherwise specified, the receiver includes Figure 4 2. The same elements of the receiver 220 as shown in FIG. 2 are shown in FIG. 2, wherein like elements have reference numerals increased by "1000."

[0439] In contrast to the receiver described above, in this arrangement, the receiver includes a diode rectifier 1253. Diode rectifier 1253 is electrically connected to input stage 1250 and receiver DC / DC converter 1226. Voltage detector 1390 detects the rectified voltage at the output of diode rectifier 1253. Diode rectifier 1253 rectifies the power signal extracted by receiving element 1229 from the field generated by a transmitter (e.g., transmitter 210). While the illustrated arrangement includes input stage 1250 and DC / DC converter 1226, those skilled in the art will appreciate that one or both of these elements may be absent.

[0440] Although not shown, the receiver controller 1320 can be powered by a power supply at the receiver. For example, the receiver can also include an auxiliary DC / DC converter at the output of the diode rectifier 1253 that converts the rectified signal to a suitable range for powering the receiver controller 1320. The auxiliary DC / DC converter can be electrically connected to the diode rectifier 1253 and the controller 1320.

[0441] Similar to the described embodiment, voltage detector 1390 detects the rectified voltage at the output of diode rectifier 1253. Receiver controller 1320, which may be in the form of a microcontroller, receives this rectified voltage as input and passes it to the transmitter from which the receiver wirelessly receives power.

[0442] Now go to Figure 9 , the schematic diagram shows in more detail Figure 8 Receiver elements. As shown, receiving element 1229 includes two inductive elements 1231, such as coils, electrically connected to capacitors C100 and C101. Capacitors C100 and C101 are receiver resonator capacitors. In the illustrated arrangement, receiving element 1229 is shown as including two elements, but fewer or more elements may be present. Furthermore, as will be understood by those skilled in the art, the receiving element may include a capacitive element, such as 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 arrangement, the receiver will extract power from the generated electric field rather than the magnetic field.

[0443] Capacitors C100 and C101 are electrically connected to input stage 1250. Input stage 1250 includes an LC circuit consisting of a capacitor / inductor pair C102 / L100 and a capacitor / inductor pair C103 / L101. Capacitors C102 and C103 are grounded at their midpoint terminals. The LC circuit filters high-frequency components from receive element 1229 for electromagnetic compatibility (EMC) purposes 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 also includes capacitors C104 and C105 to block low-frequency components.

[0444] 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 dual-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. Additionally, as those skilled in the art will appreciate, input stage 1250 as a whole may not be included.

[0445] Input stage 1250 is electrically connected to diode rectifier 1253, which includes diodes D100, D101, D102, and D103 forming 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 the alternating current (AC) signal at its input to a direct current (DC) signal at its output.

[0446] Although not in Figure 9 1253 , but the output of the diode rectifier 1253 is electrically connected to the DC / DC converter 1226 . In addition, the voltage detector 1390 detects the rectified voltage at the output of the diode rectifier 1253 .

[0447] Because diode rectifier 1253 is asynchronous, there are no synchronous rectifiers to switch to transmit the rectified voltage. Instead, in this arrangement, communication between the receiver and transmitter is performed by switching a resistor at the output of diode rectifier 1253 or a capacitor at the input of diode rectifier 1253 to modulate data onto the main power signal. This switching is performed by controlling a MOSFET connected to the resistor or capacitor.

[0448] In the arrangement shown, the capacitor is switched at the input of the diode rectifier 1253. The input connection is made by Figure 9 The arrows in Rx2TxIB are shown. Figure 10 , shows a circuit diagram of a switching circuit forming part of a receiver. Figure 10 As shown, capacitor C502 is connected to the input of diode rectifier 1253. Resistor R500 is directly connected to the input of diode rectifier 1253 via node Rx2Tx1B. In the illustrated arrangement, resistor R500 is a 0 ohm jumper, although it could be a resistor of some non-zero value. As will be appreciated by those skilled in the art, resistor R500 could be omitted. If resistor R500 were not included, capacitor C502 would be directly connected to the input of diode rectifier 1253.

[0449] Figure 10The IBSW_Control node is shown electrically connected to a receiver controller 1320. Controller 1320 controls the operation of MOSFET Q500. Receiver controller 1320 is connected to MOSFET Q500 via resistor R501. While MOSFET Q500 is shown as including diodes D501 and D502 connected between pins 3 and 4, 8, those skilled in the art will appreciate that these diodes D501 and D502 may be omitted. In the illustrated arrangement, resistor R501 is a zero-ohm jumper, although it may alternatively be a resistor of some non-zero value. As those skilled in the art will appreciate, resistor R501 may be omitted.

[0450] In use, the receiver controller 1320 controls the operation of the MOSFET Q500 to selectively charge the 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.

[0451] Although the receiver is already Figures 8 to 10 Although described and shown in the embodiment as transmitting the rectified voltage in a certain manner, those skilled in the art will appreciate that other configurations are possible. For example, the receiver controller 1320 may include a communication module that transmits the rectified voltage to the transmitter via a communication protocol including Bluetooth, Wi-Fi, or any other suitable communication protocol.

[0452] As described, the receiver 300 transmits data (eg, rectified voltage) to the transmitter (eg, transmitter 210). The transmitter receives the communicated data and controls the output voltage of the DC / DC converter 214. Figure 11 , shows an embodiment of a transmitter 330 according to one aspect of the present disclosure. The transmitter 330 is suitable for use with the receiver 300 described.

[0453] Transmitter 330 includes a power supply 332, a DC / DC converter 334, a circuit 336 including an inverter 338 and an output stage 340, and a transmitting element 342. Power supply 332 is electrically connected to DC / DC converter 334. Power supply 332 is adapted to provide a power signal to DC / DC converter 334. Power supply 332 is adapted to provide a DC power signal to DC / DC converter 334.

[0454] A DC / DC converter 334, i.e., a main transmitter DC / DC converter, is electrically connected to the power source 332 and the circuit 336. Specifically, the DC / DC converter 334 is electrically connected to the inverter 338 of the circuit 336. The DC / DC converter 334 is adapted to convert the power signal received from the power source 332 to a desired voltage level.

[0455] Circuit 336 is electrically connected to transmitting element 342 and DC / DC converter 334. Specifically, inverter 338 is electrically connected to DC / DC converter 334, and output stage 340 is electrically connected to transmitting element 342. Inverter 338 is also electrically connected to output stage 340. Inverter 338 is adapted to convert the converted DC power signal from DC / DC converter 334 into an alternating current (AC) signal. Inverter 338 may include a high-frequency power inverter. Output stage 340 is adapted to match the output impedance of inverter 338 to the optimal impedance of the wireless power link between transmitting element 342 and a corresponding receiving element (e.g., receiving element 229, 302, 1229). Output stage 340 is additionally or alternatively adapted to filter high-frequency harmonic components of 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.

[0456] Transmitting element 342 is electrically connected to circuit 336. Specifically, transmitting element 342 is electrically connected to output stage 340. Transmitting element 342 includes one or more inductive elements, i.e., inductors. The inductive elements may include one or more coils. The coils may include booster and / or shielding coils, such as those described in applicant's U.S. Patent Application No. 17 / 193,539, the relevant portions of which are incorporated herein by reference.

[0457] In another arrangement, the transmitting element 342 includes one or more capacitive elements, such as capacitive electrodes. The capacitive electrodes can be elongated electrodes spaced laterally apart; however, those skilled in the art will appreciate that other configurations are possible, including but not limited to concentric, coplanar, circular, elliptical, disk-shaped, and other electrodes. Other suitable electrode configurations are described in Applicant's U.S. Patent No. 9,979,206 B2, the relevant portions of which are incorporated herein by reference. As those skilled in the art will appreciate, the transmitting element 342 can include a combination of inductive and capacitive elements.

[0458] The transmitting element 342 may generally correspond to (eg, be the same as) the receiving element (eg, receiving element 229 , 302 , 1229 ) to enable wireless power transfer from the transmitter 330 to the receiver (eg, receiver 220 , 300 ).

[0459] 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.

[0460] Microcontroller 346 is electrically connected to LDO regulator 344 and detector 348. Microcontroller 346 is adapted to decode data sent by receiver to transmitter 330 based on parameter changes 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 rectified voltage transmitted (detected) at receiver 300 (specifically, at the output of rectifier element 308 of receiver 300).

[0461] Controlling the output voltage of DC / DC converter 334 controls the input voltage of inverter 338. Controlling the input voltage of inverter 338 can change the field generated by the transmitter 342 elements. As described, changes to medium 332 can negatively impact the average power transfer efficiency between transmitter 330 and receiver 300. These changes are observable via the rectified voltage at receiver 300, which is transmitted to transmitter 330. Transmitter 330 controls the input voltage of inverter 338 to change the strength of the generated field, thereby improving the average power transfer efficiency to receiver 300.

[0462] The detector 348 is electrically connected to the output stage 340, or the DC / DC converter 334 and the inverter 338. The detector is adapted to detect parameter changes at the transmitter 330, as will be described.

[0463] The output voltage of DC / DC converter 334 can change from a first voltage level to a second voltage based on the rectified voltage. Controller 320 can monitor rectified voltage Vrect via voltage detector 390 over a period of time. If rectified voltage Vrect changes significantly enough within a sufficiently short period of time, controller 320 transmits the new rectified voltage Vrect to transmitter 330 by changing the synchronization operation as described, thereby changing the output voltage to the second level. For example, if rectified voltage Vrect drops by 4V within 1 second, controller 346 can determine to increase the output voltage of DC / DC converter 334 (the input voltage of inverter 338). If rectified voltage Vrect increases by a similar amount within a similar time frame, controller 346 can determine to control DC / DC converter 334 to decrease its output voltage (the input voltage of inverter 338).

[0464] The decision made by 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 receiver 300 is closer to transmitter 330 than expected, i.e., the separation distance has decreased, and the medium 232 has a reduced thickness or width. Alternatively, if the rectified voltage is lower than expected, it may indicate that receiver 330 is farther away from transmitter 310 than expected. The expected rectified voltage may be the rectified voltage at which receiver 220 is currently operating. Due to variations in the medium (such as composition) in addition to distance, the rectified voltage may be higher than expected. For example, if system 200 is operating through a medium consisting of glass but is then moved to operate through a medium consisting of wood, the rectified voltage may decrease.

[0465] Once controller 346 receives the rectified voltage from controller 320 at the receiver (via the described synchronous operation switching), it can initiate an optimization sequence. In this 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 10V. This voltage is used to generate a field at transmitting element 342. The rectified voltage at receiver 300, which is related to the power extracted from the generated field, is transmitted to transmitter 330. Controller 346 then makes a decision whether to increase or decrease the input voltage. If the rectified voltage Vrect is within an acceptable range (determined through experimentation), the decision may be to switch to a higher inverter 338 input voltage. If the rectified voltage Vrect is too high or too low, the decision may be to shut down the wireless power transfer system / restart optimization. Shutting down the system may mean reducing the input voltage to 0V, so that no field is generated.

[0466] If the rectified voltage Vrect is too high, the receiver 300 may be too close to the transmitter 330. The high rectified voltage Vrect at the output of the rectifier element 308 may damage electrical components, such as diodes, at the receiver 300. Therefore, the input voltage must be kept low to prevent damage that could negatively affect the switching node tuning at the receiver 300.

[0467] If the rectified voltage Vrect is too low, the receiver 300 may be too far away from the transmitter 330. In this case, not enough power may be extracted to power the load 332 of the receiver 300, or the current into the rectifier element of the receiver 300 may be too high (because of the low voltage), which may cause excessive heating at the receiver 300 or unstable power transmission.

[0468] Will refer to Figure 12 The microcontroller 346 and the detector 348 are described in more detail. Figure 123. A portion of an embodiment of transmitter 330 is shown in greater detail in FIG. In the illustrated arrangement, LDO regulator 344 is powered by DC / DC converter 334 and also powers 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 to be sent by the receiver to transmitter 330.

[0469] Although LDO regulator 344 has been described as being powered by DC / DC converter 334, those skilled in the art will appreciate that other configurations are possible. For example, LDO regulator 344 can be connected to a power source, such as a mains supply, that powers DC / DC converter 334. Alternatively, LDO regulator 344 can be powered by an auxiliary DC / DC converter connected to the power source.

[0470] In the illustrated arrangement, detector 348 detects a voltage waveform, i.e., detector 348 is a voltage detector. Detector 348 detects the voltage waveform based on changes in voltage 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 the voltage waveform based on changes in voltage at two nodes, those skilled in the art will appreciate that detector 348 can be connected to only a single node. For example, detector 348 can detect the voltage waveform based on changes in voltage Vres-tx at the output of output stage 340.

[0471] In the illustrated arrangement, 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 to DC / DC converter 334 and is connected in parallel to the series combination of inductor 352, having inductance LZVS-t, and main switch 358, designated as Q1-t. In the illustrated arrangement, main switch 358 comprises an n-type MOSFET. While an n-type MOSFET is illustrated, those skilled in the art will appreciate that other FETs and switching devices may be used.

[0472] The main switch 358 is electrically connected to the gate driver 354, which is electrically connected to the 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 includes an oscillator. Those skilled in the art will understand that the clock generator 356 can include any signal generator.

[0473] The clock generator 356 is configured to generate a clock signal to control the gate driver 354 connected to the main switch 358 to invert the input power signal from the power supply 332 (via the DC / DC converter 334 ) into an RF or AC signal.

[0474] Inverter 338 also includes a diode 360, designated 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 capacitor 364 having a capacitance CZVS-t2, which is electrically connected in series with 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.

[0475] In the arrangement shown, the output stage 340 includes an inductor 370 having an inductance L1-tx electrically connected in series to an inductor 372 having an inductance L1-tx, and a capacitor 374 having a capacitance C1-tx electrically connected between a shared node of the inductors 370, 372 and a return.

[0476] As described, the detector 348 detects a voltage waveform based on a change in the voltage at at least one of the two nodes (e.g., V1 at the midpoint of the output stage 340 and Vres-tx at the output of the output stage 340). The detector 348 outputs a logic level signal, i.e., a logic level, which the microcontroller 346 decodes into data sent by the receiver to the transmitter 330, such as a rectified voltage at the output of the rectifier element 308 of the receiver 300.

[0477] The detector 348 is electrically connected to the transmitter DC / DC converter 334. Specifically, 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. Controlling the output voltage of the DC / DC converter 334 controls the strength of the field generated by the transmitting element 342 of the transmitter 330 via the inverter 338.

[0478] Now go to Figure 13 , showing detector 348 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 scaling circuit 380, peak detector 382, ​​filter 384, and signal conditioner and comparator 386.

[0479] In operation, scaling circuit 380 receives detected waveforms, such as V1 and Vres-tx. Scaling circuit 380 reduces the amplitude of the detected waveform to facilitate waveform processing. The reduced-amplitude waveform is then fed to peak detector 382, ​​which converts the signal into a DC voltage. When a sudden change in the RF signal input to peak detector 382 occurs due to the switching operation of the receiver's synchronous rectifiers, the signal output from peak detector 382 changes proportionally. Filter 384 (i.e., the input filter stage) filters this output. For example, filter 384 filters the 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. Signal conditioner and comparator 386 amplifies the signal and then compares the amplified voltage level to a reference voltage level. Signal conditioner and comparator 386 may include a comparator. Whenever a sufficiently large modulation occurs in the RF input voltage signal, signal conditioner and comparator 386 outputs a logic-level signal.

[0480] 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 logic level signal with a binary sequence representing the data sent from the receiver to the transmitter 330.

[0481] This is similar to the process performed at the receive microcontroller 320 that receives or generates data for transmission to a transmitter, such as transmitter 330. Similar to the transmit microcontroller 346, the receive microcontroller 320 encodes the data to be transmitted into a time sequence of synchronous and non-synchronous operation of the synchronous rectifiers, which results in changes in the waveform detected at the transmitter.

[0482] Now go to Figure 14 , a flow chart illustrating a method 400 for wireless power transfer over a medium (e.g., medium 332) between a receiver (e.g., receiver 300) and a transmitter (e.g., transmitter 330) is shown. The method 400 includes detecting 402 a rectified voltage at the output of the rectifier element 254, 308 of the receiver 200, 300 via the voltage detector 390 of the receiver 200, 300. The detection 402 may be performed directly by the microcontroller 320 at the receiver 200, 300.

[0483] The method 400 also includes transmitting 404 the detected rectified voltage to a transmitter, such as transmitter 210, 330, via the controller 320. The controller 320 may transmit the rectified voltage using a conventional communication protocol (eg, Wi-Fi, Bluetooth).

[0484] Alternatively, the controller 320 can communicate the rectified voltage by switching synchronous operation of the rectifier elements 308 in the manner described. Additionally, the controller 320 can communicate by controlling a MOSFET to switch a resistor at the output of the diode rectifier 1253, or to switch a capacitor at the input of the diode rectifier 1253 to modulate data onto the main power signal, as described.

[0485] In this case, the method 400 may also include encoding the detected rectified voltage into a time sequence for modifying the operation of the synchronous rectifier. The method 400 may also include modifying the operation, which may include selectively enabling and / or disabling the operation of the gate driver 310, the trigger circuit 306, and / or the auxiliary DC / DC converter 314. This selective switching of the components of the synchronous rectifier is performed according to the encoded rectified voltage to be transmitted, so that the parameter changes generated at the transmitter 330 indicate the rectified voltage to be transmitted from the receiver 300 to the transmitter 330.

[0486] Method 400 also includes detecting 406 a parameter change at transmitter 330 based on the modification of the operation of the synchronous rectifier. As depicted, detector 348 detects a voltage waveform at transmitter 330 based on the modification of the operation of the synchronous rectifier.

[0487] The method 400 also includes determining 408 data (e.g., a rectified voltage) to be transmitted from the receiver 300 to the transmitter 330 based on the parameter change (i.e., the detected parameter change). As described above, the detector 348 processes the detected waveform and compares the processed waveform with a voltage level to generate a logic level signal, which is decoded into the data transmitted from the receiver 300 to the transmitter 330.

[0488] This method of transmitting data can be more efficient than existing methods while allowing for higher data transfer rates. In addition, this method can operate with a receiver including a synchronous rectifier by selectively switching the operation of the synchronous rectifier to transmit data to a transmitter from which the receiver draws power.

[0489] The method may further include controlling 410, via the controller 346 of the transmitter 330, an output voltage of the 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 via changes in the rectified voltage can be accounted for by controlling the output voltage to improve average power transmission efficiency between the transmitter 330 and the receiver 300.

[0490] The method may also include generating 412 a field for wirelessly transmitting power through the medium to the receiver 220, 300 via the transmitter resonator (i.e., the transmit element 224, 342 of the transmitter 210, 330). The strength of the field is based on the output voltage of the converter 214, 334 (the input voltage of the inverter 216, 338).

[0491] An experimental setup of receiver 300 and transmitter 330 was tested to evaluate performance. To simulate a fixed-coupled wireless link between transmitter 330 and receiver 300, an equivalent T-network was used to connect transmitter 330 and receiver 300. To switch receiver 300 between synchronous and asynchronous operation, a function generator was used to enable / disable receiver 300's auxiliary DC / DC converter 314, which powers the synchronous rectifier's gate driver 310. All tests were performed with no load on receiver 300. Operation of receiver 300 and transmitter 330 was performed under load conditions at receiver 300. The experimental setup primarily used magnetic field coupling to transfer power from transmitter 330 to receiver 300. The experimental setup had an operating frequency of 13.56 MHz.

[0492] The transmitter RF voltage V1 and transmitter current Iin were measured while the synchronous rectifier was modulated between synchronous and non-synchronous operation. The results of this test are given in Figures 15 to 19 Shown in.

[0493] Figure 15 is a graph of the voltage and current waveforms of the transmitter 330 . Figure 15 The response of these voltage and current waveforms when the receiver 300 is modulated at a frequency of 1700 Hz is shown. As shown, the voltage waveform ranges from +18 V to -18 V, with peaks at +18 V and -18 V and valleys at +6 V and -6 V. The current waveform ranges from almost 1000 mA to a steady state of approximately 112-117 mA.

[0494] Figure 16 is a graph of the voltage rise time of the transmitter 330 for an exemplary period of the voltage waveform. Figure 16 As shown, during the rise time of 1.777 μs, the waveform exhibits a sharp increase in voltage of 2.612 V.

[0495] Figure 17 is a graph of the voltage fall time of the transmitter 330 for an exemplary period of the voltage waveform. Figure 17 As shown, during the falling time of 2.228 μs, the waveform shows a sharp decrease in voltage of 4.939 V.

[0496] Figure 18is a graph of the current rise time of transmitter 330 for an exemplary period of the current waveform. Figure 18 As shown, during the rise time of 31.247 μs, the waveform exhibits a current increase of 548.984 mA.

[0497] Figure 19 is a graph of the current fall time of the transmitter 330 for an exemplary period of the current waveform. Figure 19 As shown, during the fall time of 46.633 μs, the waveform shows a sharp decrease in the current of 612.376 mA.

[0498] These graphs illustrate changes in detectable voltage and current waveforms based on changes in the operation of the synchronous rectifiers to transmit data from the receiver to the transmitter.

[0499] Although a particular transmitter 330 is described, those skilled in the art will appreciate that other configurations are possible. Figure 20 , shows another embodiment of a portion of a transmitter. In this embodiment, the transmitter includes the same components as transmitter 330, with the same elements having reference numbers increased by 100. LDO regulator 444 is powered by DC / DC converter 434 and also powers controller 446. Controller 446 receives a signal from detector 448. Detector 448 outputs a logic level signal (i.e., a logic level), which controller 446 decodes into data to be sent by the receiver to the transmitter.

[0500] In the arrangement shown, the detector 448 detects one or more current waveforms, ie, the detector 448 is a current detector. The detector 448 detects a current waveform based on changes in current at a single node (eg, Iin at the output of the DC / DC converter 434).

[0501] Because the transmitter's input DC current changes depending on the impedance it sees, this signal (i.e., Iin) can alternatively or additionally be used as a source for a detector 448 (e.g., a current demodulator), which filters the detected DC current and generates a logic level signal reflecting the change in the transmitter's DC current level. This signal is then transmitted to a controller 446, such as a microcontroller. Controller 446 then controls the output voltage of the transmitter's DC / DC converter 434 based on the decoded rectified voltage from the receiver.

[0502] Now go to Figure 21, shows detector 448, i.e., a current detector, in more detail. Detector 448 demodulates the current waveform detected at the transmitter, as will be described. In other words, detector 448 comprises a current demodulator. Detector 448 includes current sensing circuit 480, filter 482, and signal conditioner and comparator 484.

[0503] In operation, current sensing circuit 480 detects a current signal, such as input current Iin. Current sensing circuit 480 also scales the sensed current to a smaller amplitude. Current sensing circuit 480 also converts the sensed current (e.g., the scaled sensed current) into a voltage signal proportional to the sensed current. Filter 428 (i.e., input filter stage) filters the output (i.e., the converted voltage). For example, 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 signal conditioner and comparator 484. Signal conditioner and comparator 484 amplifies the signal and then compares the amplified voltage level to a reference voltage level. Signal conditioner and comparator 484 may include a comparator. Whenever a sufficiently large modulation occurs in the input current Iin signal, signal conditioner and comparator 484 outputs a logic level signal.

[0504] The output logic level signal is then provided to the controller 446 for decoding. The controller 446 determines the time between the modulated pulses to decode the logic level signal in the binary sequence that represents the data sent from the receiver to the transmitter. The data is the rectified voltage detected at the receiver, which is used to control the operation of the DC / DC converter 434.

[0505] It should be understood that the examples provided are merely examples of the present disclosure and that various modifications may be made thereto.

Claims

1. A method for wireless power transmission via 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; as well as A field for wirelessly transmitting power through a medium to a receiver of the wireless power transmission system is generated via a transmission resonator of the transmitter, the transmission resonator being electrically connected to the inverter.

2. The method according to claim 1, further comprising: The parameter is detected at the transmitter and / or the receiver of the wireless power transfer system.

3. The method according to claim 2, wherein: The parameters include a rectified voltage at the receiver of the wireless power transfer system.

4. A method according to any preceding claim, wherein: Controlling the input voltage of the inverter includes: An output voltage of a converter electrically connected to the inverter is controlled.

5. The method according to any preceding claim, further comprising: The detected parameters are transmitted to the transmitter.

6. The method according to claim 5, wherein: The communication includes: The detected parameters are transmitted from the receiver to the transmitter.

7. The method according to any preceding claim, further comprising: The parameter is monitored over a period of time.

8. The method according to claim 7, wherein: Controlling the input voltage of the inverter includes: An input voltage of the inverter is controlled based on changes in the monitored parameter over the time period.

9. A method according to any preceding claim, wherein: The medium includes windows, glass, building structures, concrete or wood.

10. A method for wireless power transmission via a medium, the method comprising: powering a transmit resonator of a transmitter of a wireless power transmission system with an input voltage via an inverter to generate a field for wirelessly transmitting power through a medium to a receiver of the wireless power transmission system; as well as The input voltage of the inverter is optimized based on the detected parameters.

11. The method according to claim 10, wherein: Optimizing the input voltage includes adjusting the input voltage from a first voltage level to a second voltage level based on the detected parameter.

12. The method according to claim 10 or 11, wherein: Adjusting the input voltage includes continuously adjusting the input voltage between a plurality of voltage levels.

13. The method according to any one of claims 10 to 12, further comprising: The parameter is detected at the transmitter and / or the receiver of the wireless power transfer system.

14. The method according to any one of claims 10 to 13, wherein The parameters include a rectified voltage at the receiver of the wireless power transfer system.

15. The method according to claim 14, further comprising: The rectified voltage is transferred from the receiver to the transmitter.

16. A controller configured to control an inverter of a transmitter of a wireless power transmission system, a converter of the transmitter, at least one of the transmitter and a receiver of the wireless power transmission system to perform the method according to any preceding claim.

17. A transmitter of a wireless power transmission system, the transmitter configured to wirelessly transmit power to a receiver of the wireless power transmission system via a medium, the transmitter comprising: a transmitting resonator for wirelessly transmitting power to a receiver of the wireless power transmission system through a medium; an inverter electrically connected to the transmission resonator; and A controller is configured to control an input voltage of the inverter based on the detected parameter.

18. The transmitter according to claim 17, further comprising: A sensor is used to detect the parameter at the transmitter and / or the receiver.

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

20. The transmitter according to any one of claims 17 to 19, further comprising: A communication module is configured to receive the parameter from a receiver of the wireless power transmission system.

21. A wireless power transmission system, comprising: a transmitter comprising a transmitter resonator and an inverter, the transmitter resonator being configured to wirelessly transmit power to a receiver of the wireless power transmission system through a medium, the inverter being electrically connected to the transmitter resonator; a receiver comprising a receiver resonator for wirelessly extracting power from the transmitter via electric and / or magnetic field coupling; and A controller is configured to control an input voltage of the inverter based on the detected parameter.

22. The system of claim 21, further comprising: A sensor is used to detect the parameter at the transmitter and / or the receiver.

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

24. A system according to any one of claims 21 to 23, wherein The receiver further comprises: A communication module is configured to transmit the parameter from the receiver to the transmitter.

25. The system according to any one of claims 21 to 24, wherein The transmitter further comprises: A communication module is configured to receive the parameter from the receiver.

26. A system according to any one of claims 21 to 25, wherein The transmitter further comprises: A converter is electrically connected to the inverter.

27. The system of claim 26, wherein: The controller is configured to control an output voltage of the converter based on the detected parameter.

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