Active Rectification in Wireless Power Systems

Abstract

Disclosed herein are methods and systems for controlling an active rectifier of a wireless power receiver. An exemplary method may include determining a reference value of current entering the rectifier, the reference value being based on a requirement of a load; determining a value change in the required input current currently entering the rectifier based on the reference value; transmitting to the wireless power transmitter a signal representing the value change in the required input current; determining a new value of the current input current after the signal is transmitted; and, when the new value is within a predetermined range of the required value change, driving at least one transistor in the rectifier with a PWM signal based on the new value.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and rights to U.S. Provisional Application No. 62 / 986,212, entitled “Active Rectification in Wireless Power Systems,” filed March 6, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003] The following disclosure relates to methods and systems for active rectification in wireless power systems, and more specifically to methods and systems for charging and / or heating high-voltage batteries using a wireless power receiver with an active rectifier. Background Technology

[0004] Wireless power systems are configured to transfer power to a load (e.g., a battery in an electronic device) without physical contact between the transmitter and receiver. The wireless power receiver in such a system typically includes a rectifier to convert the oscillating energy into DC for delivery to the load (e.g., a battery) coupled to the receiver. High efficiency of the rectifier's operation can be advantageous. Summary of the Invention

[0005] In one aspect, this disclosure features a method for controlling an active rectifier in a wireless power receiver. The method may include: determining a reference value for a current to the rectifier, the reference value being based on a load requirement; determining a required value change for a current input current to the rectifier based on the reference value; transmitting a signal representing the required value change of the current input current to a wireless power transmitter; determining a new value for the current input current after transmitting the signal; and, when the new value is within a predetermined range of the required value change, driving at least one transistor in the rectifier with a PWM signal based on the new value.

[0006] Various embodiments of the method may include one or more of the following features.

[0007] The method may include receiving from the battery management system a request for at least one of the following: voltage from the wireless power receiver, current from the wireless power receiver, or power from the wireless power receiver. The method may also include determining an alternative reference value for the current to the rectifier when the new value is not within a predetermined range.

[0008] Transmitting a signal representing a desired change in the current input current to a wireless power transmitter can cause a change in the power transmitted from the wireless power transmitter to the wireless power receiver. The new value of the current input current can be based on the change in transmitted power. The change in transmitted power can decrease the power. The change in transmitted power can decrease the power to zero. The change in transmitted power can increase the power. This method may include comparing the new value of the current input current with a predetermined range of the desired change in value. This method can be executed by a controller coupled to an active rectifier.

[0009] In another aspect, this disclosure features a controller for controlling an active rectifier of a wireless power receiver, the controller being coupled to the rectifier. The controller can be configured to perform the following steps: determining a reference value for the current to the rectifier, the reference value being based on load requirements; determining a required change in the current input current to the rectifier based on the reference value; transmitting a signal representing the required change in the current input current to a wireless power transmitter; determining a new value for the current input current after transmitting the signal; and, when the new value is within a predetermined range of the required change in the current value, driving at least one transistor in the rectifier with a PWM signal based on the new value.

[0010] Various embodiments of the controller may include one or more of the following features.

[0011] The controller can be configured to receive a request from a battery management system coupled to the output of the rectifier for at least one of the following: voltage from the wireless power receiver, current from the wireless power receiver, or power from the wireless power receiver. The controller can be configured to determine an alternative reference value for the current to the rectifier when the new value is not within a predetermined range. Transmitting a signal indicating a change in the requested value of the current input current to the wireless power transmitter can cause a change in the power transmitted from the wireless power transmitter to the wireless power receiver. The new value of the current input current can be based on the change in the transmitted power.

[0012] A change in the transmitted power can decrease the power. A change in the transmitted power can decrease the power to zero. A change in the transmitted power can increase the power. The controller can be configured to compare the new value of the current input current with a predetermined range of changes required to the value. The controller can be coupled to at least one transistor in the rectifier.

[0013] In another aspect, this disclosure is characterized by an active rectifier for a wireless power receiver. The active rectifier may include: a first diode coupled between a first input and an output of the rectifier; a first transistor coupled between the first input and ground; a first capacitive buffer coupled in parallel to at least one of: (i) the first diode or (ii) the first transistor; a second diode coupled between a second input and an output of the rectifier; a second transistor coupled between the second input and ground; and a second capacitive buffer coupled in parallel to at least one of: (i) the second diode or (ii) the second transistor.

[0014] Various embodiments of an active rectifier may include one or more of the following features.

[0015] The first and second capacitive buffers can be configured to reduce reactive current in the wireless power receiver. The first and second capacitive buffers can also be configured to reduce switching losses of their respective first and second transistors. Each of the first and second capacitive buffers may include a resistive component. Each of the first and second capacitive buffers may include multiple capacitors. The wireless power receiver can be configured to deliver approximately 11 kW of power to a load coupled to the output of an active rectifier, wherein each capacitive buffer has a capacitance between 1 and 30 nanofarads.

[0016] The active rectifier can be configured to operate at a frequency of 85 kHz + / - 10 kHz. The wireless power receiver may include a receiver resonator coil configured to be coupled to the wireless power transmitter via an electromagnetic field, and the impedance presented by the active rectifier to the receiver resonator coil may be resistive when the active rectifier is operating. The active rectifier can be configured to provide current for charging a battery coupled to the output of the rectifier. The active rectifier can be configured to provide current to a resistor coupled to the output of the rectifier.

[0017] In another aspect, this disclosure features a wireless power receiver comprising: a receiver resonator coil configured to be coupled to a wireless power transmitter via an electromagnetic field; and an active rectifier coupled to the output of the receiver resonator coil. The active rectifier may include: a first diode coupled between a first input and an output of the rectifier; a first transistor coupled between the first input and ground; a first capacitive buffer coupled in parallel to at least one of: (i) the first diode or (ii) the first transistor; a second diode coupled between a second input and an output of the rectifier; a second transistor coupled between the second input and ground; and a second capacitive buffer coupled in parallel to at least one of: (i) the second diode or (ii) the second transistor.

[0018] Various embodiments of a wireless power receiver may include one or more of the following features.

[0019] The first and second capacitive buffers can be configured to reduce reactive current in the wireless power receiver. The first and second capacitive buffers can also be configured to reduce switching losses of their respective first and second transistors. Each of the first and second capacitive buffers may include a resistive component. Each of the first and second capacitive buffers may include multiple capacitors. The wireless power receiver is configured to deliver approximately 11 kW of power to a load coupled to the output of an active rectifier, and each capacitive buffer has a capacitance between 1 and 30 nanofarads.

[0020] The active rectifier can be configured to operate at a frequency of 85kHz + / - 10kHz. When the active rectifier is operating, the impedance presented by the active rectifier to the receiver resonator coil can be resistive. The active rectifier can be configured to provide current for charging a battery coupled to the rectifier's output. The active rectifier can be configured to provide current to a resistor coupled to the rectifier's output.

[0021] In another aspect, this disclosure features a method for active rectification in a wireless power receiver. The method may include: receiving a current signal from an input of an active rectifier of the receiver; detecting a zero-crossing of the current signal to generate a zero-crossing detection signal; detecting the phase of the zero-crossing detection signal to generate a synchronization signal; generating a ramp signal based on the synchronization signal; and generating a pulse-width modulation (PWM) signal for each transistor in the active rectifier.

[0022] Various embodiments of the method may include one or more of the following features. The method may also include providing a PWM signal to an active rectifier. The current signal includes one or more harmonics. Attached Figure Description

[0023] Figure 1 This is a block diagram of an exemplary wireless power system.

[0024] Figures 2A to 2B This is a schematic diagram of a wireless power system configured to operate in charging and / or heating modes.

[0025] Figures 2C to 2D This is a schematic diagram of an example active rectifier with a capacitive buffer.

[0026] Figure 3 This is a diagram of an exemplary control system for a wireless power system configured to operate in dual modes.

[0027] Figures 4A to 4C It is aimed at Figure 3 A flowchart of an exemplary method of an exemplary control system.

[0028] Figure 5 This is a graph of an exemplary control system, including current measurement results, for a wireless power system configured to operate in dual modes.

[0029] Figure 6 This is a schematic diagram of an exemplary wireless power system including an active rectifier.

[0030] Figure 7A It is used to generate targets Figure 2B or Figure 6 A block diagram of the control signals for the transistors (multiple) of an exemplary active rectifier.

[0031] Figure 7B It is used to generate targets Figure 2B or Figure 6 A block diagram illustrating an example workflow for the control signals of the transistors (multiple) of an exemplary active rectifier.

[0032] Figure 8 yes Figures 2A to 2B or Figure 6 A collection of time-varying curves of various signals in a wireless power system. Figures 2A to 2B or Figure 6 Wireless power systems include Figure 2B or Figure 6 An exemplary active rectifier.

[0033] Figures 9A to 9K yes Figure 2B or Figure 6 Various states of an exemplary active rectifier as it changes over time.

[0034] Figure 10 It is aimed at Figures 2A to 2Bor Figure 6 A flowchart illustrating an exemplary method of active rectification in a wireless power system.

[0035] Figure 11 This is a block diagram of an example computer system that can be used to implement the exemplary systems and methods described herein. Detailed Implementation

[0036] This document discloses exemplary embodiments of wireless power systems including active rectifiers. In various embodiments, such systems can be configured to charge or heat high-voltage batteries (e.g., in automobiles, industrial equipment, machinery, robots, etc.).

[0037] Wireless power systems

[0038] Figure 1 This is a block diagram of an exemplary wireless power system 100. System 100 includes a wireless power transmitter 102 and a wireless power receiver 104. In transmitter 102, a power source 105 (e.g., AC mains, battery, etc.) supplies power to inverter 108. Additional components may include power factor correction (PFC) circuitry 106 in front of inverter poles 108. Inverter 108 drives transmitter resonator coils and capacitive components 112 (“resonators”) via impedance matching network 110 (including fixed network components and / or tunable network components). The transmitter resonator generates an oscillating magnetic field that induces current and / or voltage in receiver resonators. The received energy is supplied to rectifier 118 via impedance matching network 116 (including fixed network components and / or tunable network components). Finally, the rectified power is supplied to load 120 (e.g., one or more batteries of an electric or hybrid vehicle). In some embodiments, battery voltage levels can affect various parameters of wireless power system 100 (e.g., impedance). Therefore, the battery voltage level can be received, determined, or measured as input to other parts of the wireless power system 100. For example, typical battery voltage ranges for electric vehicles include 0 to 280V, 0 to 350V, 0 to 420V, etc.

[0039] In some embodiments, one or more components of transmitter 102 may be coupled to controller 122, which may include a communication module (e.g., Wi-Fi, radio, Bluetooth, in-band signaling mechanism, etc.) configured to communicate with a communication module of receiver 104. In some embodiments, one or more components of transmitter 102 may be coupled to one or more sensors 124 (e.g., current sensor, voltage sensor, power sensor, temperature sensor, fault sensor, etc.). Controller 122 and sensors(s)124 may be operatively coupled to the control portion of transmitter 102 based on feedback signals from sensors(s)124 and / or sensors(s)128.

[0040] In some embodiments, one or more components of receiver 104 may be coupled to controller 126, which may include a communication module (e.g., Wi-Fi, radio, Bluetooth, in-band signaling mechanism, etc.) configured to communicate with the communication module of transmitter 102. In some embodiments, one or more components of transmitter 104 may be coupled to one or more sensors 128 (e.g., current sensor, voltage sensor, power sensor, temperature sensor, fault sensor, etc.). Controller 126 and sensors(s)128 may be operatively coupled to the control section of transmitter 102 based on feedback signals from sensors(s)128 and / or sensors(s)124.

[0041] Examples of wireless power systems can be found in U.S. Patent Application Publication No. 2010 / 0141042, entitled “Wireless Power Transfer System”, published June 10, 2010, and U.S. Patent Application Publication No. 2012 / 0112535, entitled “Wireless Power Transfer for Vehicles”, published May 10, 2012, both of which are incorporated herein by reference in their entirety.

[0042] High-power wireless power transmitters can be configured to transmit wireless power in applications such as powering and / or charging batteries in vehicles, industrial machines, robots, or electronic devices that rely on high power. For illustrative purposes, the following disclosure focuses on wireless power transmission for vehicles. However, it should be understood that any one or more embodiments described herein can be applied to other applications where wireless power can be utilized. For example, exemplary methods and systems can be extended to consumer electronics devices (e.g., operating at low power), general-purpose isolated DC / DC converters, buses, trucks (e.g., operating at high power), etc. Therefore, the parameters discussed herein (e.g., frequency, power level, voltage level, buffer capacitor value, etc.) are considered exemplary and can be configured according to the application.

[0043] As used herein, the term "capacitor," or the corresponding symbol, may refer to one or more electronic components having capacitance (e.g., farads) and / or capacitive reactance (e.g., ohms). For example, a capacitor may include one or more capacitors (e.g., in a capacitor "library"), which may be on the order of tens, hundreds, or other discrete capacitors. Two or more capacitors may be coupled in series or parallel to achieve a desired capacitance and / or desired capacitive reactance. Note that capacitive reactance may be expressed as a negative value herein. However, one of the prior art will recognize that, in some conventions, capacitive reactance may also be expressed as a positive value. Furthermore, this disclosure, including the accompanying drawings, provides exemplary values ​​for various electronic components, and it will be understood that the values ​​of components may be tailored to a particular application. For example, the values ​​of various electronic components may depend on whether the wireless power transmitter is used to transmit power to a vehicle battery (on the order of kilowatts) or to charge a mobile phone battery (typically less than 5 watts).

[0044] Dual-mode operation

[0045] In some embodiments, the wireless power system 100 can be configured for one or more operating modes. Operating modes may include providing energy to one or more types of loads, such as charging and / or heating a battery. In an exemplary “charging mode,” the system 100 can be configured to provide voltage to the battery. The charging mode may include a constant current (CC) mode and / or a constant voltage (CV) mode. In an exemplary “heating mode,” the system 100 can be configured to provide current to a resistor(s) configured to heat the battery(s). The heating mode may include a constant voltage (CV) mode. As discussed herein, the battery and / or resistor may be referred to as a “load.”

[0046] Figures 2A to 2B The illustration shows a wireless power system 200 (including portions 200a, 200b) configured to operate in charging and / or heating modes. The wireless power system 200 includes a wireless power transmitter 202 and wireless power receivers 204a, 204b (collectively referred to as 204). The wireless power system 200 may include components similar to or identical to those of the wireless power system 100 described above.

[0047] In the exemplary receiver section 204, the active rectifier 206 may be a full-bridge rectifier, comprising a diode D5 series coupled to transistor S7 (having a body diode D7) and a diode D6 series coupled to transistor S8 (having a body diode D8). Diodes D5 and D6 may be silicon diodes. Transistors S7 and S8 may be silicon MOSFETs. By using silicon diodes and silicon MOSFETs in the construction of the active rectifier 206, the total cost of receiver 204 and system 200 can be minimized.

[0048] In some embodiments, transistors S7 and S8 are coupled in parallel with capacitive buffers C41 and C42, respectively. In some embodiments, as... Figure 2C As shown in the diagram, diodes D5 and D6 are coupled in parallel with their respective capacitive buffers 212a and 212b. In some embodiments, such as Figure 2D The diagram shows transistors S7 and S8 coupled in parallel with corresponding capacitive buffers 214a and 214b, and diodes D5 and D6 coupled in parallel with corresponding capacitive buffers 216a and 216b. Note that in some embodiments, the positions of transistor S7 and diode D5 are interchanged, and the positions of transistor S8 and diode D6 are interchanged. Note that in some embodiments, the rectifier may have only a single capacitive buffer (e.g., spanning one transistor and not the other). Each capacitive buffer may include one or more capacitive components (e.g., capacitors). In some embodiments, the buffer capacitance may depend on the wireless power system specifications and may be on the order of one nanofarad to tens of nanofarads. In some embodiments, the capacitive buffer has a resistive portion.

[0049] When capacitive buffers are used in wireless power systems, they offer one or more advantages and / or benefits. By properly selecting the value of the capacitive buffer, the power delivered to load 120 can be increased. For example, in a wireless power system configured to deliver 10-20 kW output, a capacitive buffer can allow several hundred additional watts (e.g., 100 to 900 watts) above 10-20 kW to be delivered to load 120. For exemplary high-power wireless power systems (e.g., configured to deliver approximately 11 kW + / - 2 kW of power to a load), each capacitive buffer can have a capacitance between 1 and 30 nanofarads. In some embodiments, the buffer can have a capacitance between 12-14 nanofarads, between 10-15 nanofarads, between 5-20 nanofarads, or more. Selecting the value of the capacitive buffer can improve the matching of the wireless power receiver 204 and / or the entire system 200, thereby enabling greater power output, as discussed. In particular, it can be beneficial to ensure proper impedance matching between the receiver resonator coil and the rectifier, so that the imaginary (reactant) component of the impedance is canceled out for certain “critical” conditions (e.g., decoupling the wireless power transmitter and receiver, very high or very low battery voltage, etc.). During operation of a wireless power system, the input current of the rectifier can have high-order harmonics. For example, if the system operates at an operating frequency of approximately 85 kHz (e.g., + / - 10 kHz), the input current contains frequencies at higher harmonics of the operating frequency. Higher harmonics can create small phase shifts that cause small imaginary impedances, thus affecting the overall impedance seen by the receiver resonator coil. This can lead to defective cancellation of the imaginary impedance. By configuring rectifier 206 with a capacitive buffer, the buffer can compensate for the reactance offset of the equivalent impedance active rectifier 206. This allows the impedance seen by the receiver resonator coil to be properly compensated. Therefore, the receiver resonator coil can see a dominant resistive load impedance. As mentioned above, this configuration can enable a more efficient system to deliver more power to the load 120. The value of the capacitive buffer is selected accordingly to compensate for impedance (e.g., the reactive component of the impedance seen by the receiver resonator coil).

[0050] Exemplary capacitive buffers can be beneficial for increasing output power, reducing reactive current in wireless power system 200 (e.g., receiver 204), reducing switching losses in transistors S7 and S8, and / or improving the efficiency of wireless power receiver 204 and / or wireless power system 200.

[0051] In some embodiments, to switch to battery heating mode, the output of exemplary rectifier 206 can be coupled to switch 208, which turns on a resistor used to heat the battery. Typically, the battery heater can be a component of a vehicle (e.g., an electric vehicle, a hybrid vehicle, etc.). An exemplary battery heater (e.g., branch circuit 210) may include an array of positive temperature coefficient (PTC) resistors and a set of relays configuring an equivalent load. The power supplied to the heater can be PWM controlled. Therefore, in battery heating mode, the exemplary wireless power system can maintain a constant voltage at its output.

[0052] In some embodiments, the wireless power transmitter 202 can be configured such that:

[0053] X GA =X 1s =X 2s =X 3s

[0054] Where X 1s It is component L ls C 1sa C lsb Combined reactance; X 2s It is (multiple) components C 2s The combined reactance; and X 3s It is component L 3sa L 3sb C 3sa C 3sb The combined reactance. In the exemplary transmitter 202, the maximum current I in transmitter 200 is... 1s_max At maximum bus voltage V bus_max In some embodiments, the reactance matched to the wireless power system 202 can be configured such that:

[0055]

[0056] XGA is a component L in part 201 of transmitter 202. 1s C 1s C 2s L 3s C 3s The characteristic impedance presented.

[0057] In some embodiments, the wireless power receiver 204 may be configured such that:

[0058] X VA =X 1d =X 2d =X 3d

[0059] Where X 1dIt is component L 1d C 1da C 1db Combined reactance; X 2d It is (multiple) components C 2d The combined reactance; and X 3d It is component L 3da L 3db The combined reactance. In some embodiments, the wireless power receiver 204 can be configured such that:

[0060] X VA2 =X 1d =X 2d

[0061] X VA2 =X 3d

[0062] This allows the system to deliver greater output power. In some embodiments, impedance matching with the wireless power receiver 204 can be configured such that:

[0063]

[0064] Where X VA It is composed of part L of part 203 1d C 1d C 2d L 3d The presented reactance. In the exemplary receiver 202, the maximum current I in receiver 200 is... 1d_max At maximum battery voltage V battery_max Exemplary batteries (such as electric vehicle batteries or hybrid vehicle batteries) may have a voltage of 320-450V. DC The voltage range.

[0065] In some embodiments, during charging mode, the dual-mode wireless power system 200 can deliver full power (e.g., approximately 3.3 kW or less, approximately 6.6 kW or less, approximately 11 kW or less, approximately 21 kW or less, etc.) to some or all of the coupling range between the resonator coil (e.g., coil L1s) of the transmitter 202 and the resonator coil (e.g., coil L1d) of the receiver 204 (e.g., refer to SAE International Standard J2954_201904 "Wireless power transfer and calibration method for light plug-in / electric vehicles"). In some cases, power delivery may be less than full power ("derating") in some coupling ranges (e.g., less than 3.3 kW, less than 6.6 kW, less than 11 kW, less than 21 kW, etc.), due to the challenges of operating between the two modes. For an exemplary system 200 configured to deliver approximately 11 kW, the current in the transmitter resonator coil L1s can be 78 ARMs or less (e.g., at a bus voltage Vbus of 840 V), and the receiver resonator coil L1d can be 50 ARMs or less (e.g., at a battery voltage Vbus of 450 V). battery Note that under derating power, the current in the transmitter resonator coil L1s can be 65 ARMs or less. In some embodiments, the dual-mode wireless power system 200 can deliver power to the battery (from the input of the power source 105 to the load (e.g., battery) 120) with an efficiency of at least 88%. To achieve this level of efficiency, in some embodiments, the transistors S7, S8 of the active rectifier 206 can employ zero-voltage switching (ZVS).

[0066] In the exemplary battery "charging" mode, the active rectifier 206 can operate as a synchronous rectifier, wherein transistors S7 and S8 are used to process the sinusoidal voltage signal V. AC Rectification is performed. In this mode, the equivalent impedance of the active rectifier 206 can be configured to be resistive, thereby allowing for simplified control of the receiver 204.

[0067] In the exemplary battery "heating" mode, the active rectifier can operate in a constant voltage mode, thereby enabling low switching and conduction losses in receiver 204. In heating mode, system 200 can be rated to deliver 8kW of power.

[0068] Figure 3 This is a diagram of a control system 300 for an exemplary wireless power system configured to operate in dual modes. Figures 4A to 4C This is a flowchart of exemplary methods 400a, 400b, and 400c (collectively referred to as 400) for an exemplary control system 300. Specifically, Figures 4A to 4B The control processes 400a, 400b in receiver 204 are shown, and Figure 4C The control processes 400c in transmitter 202 are shown. For clarity and brevity, Figure 3 and Figures 4A to 4C These are discussed together here. Note that the following procedures may be performed in different orders or at different times.

[0069] Referring to method 400a, in process 402, receiver controller 302 can receive a request signal from battery management system (BMS). This request signal can be used by receiver 204 to provide a specific output power P. O Output voltage V O (represented as reference voltage signal V) O_ref ), and / or output current I O (represented as reference current signal I) O_ref This depends on the operating mode (e.g., constant current (CC) or constant voltage (CV)). In process 404, controller 302 can determine (e.g., calculate, account for, etc.) the input current I for rectifier 206. 3d Reference current I 3d_ref In process 406, controller 302 can determine (e.g., measure) current I. 3d (e.g., via a coil current sensor).

[0070] Referring to method 400c, in optional process 408, transmitter controller 304 can determine inverter voltage V. inv and / or signal INV VI Furthermore, in optional process 409, controller 304 may transmit an indication of inverter voltage V via wireless communication 306 (e.g., Wi-Fi, radio, Bluetooth, etc.). inv and / or signal INV VI The signal is sent to the receiver controller 302. Note that the signal INV... VI This refers to the phase shift of the inverter's output voltage and output current, and can be used to determine whether the inverter 108 is operating in zero-voltage switching (ZVS) mode.

[0071] Referring to method 400a, in optional process 410, controller 302 can receive inverter voltage V from transmitter 202. inv and / or signal INV VI In optional process 411a, the error signal eVA is determined (e.g., calculated). Note that eVA can be related to ε. Io ε Vo or ε Po (As described in detail below) Equal. In optional procedure 411b, the request signal GA_CMD is based on the determined current I. 3dAnd is calculated. In process 412, receiver 204 can base its calculation on the determined current I. 3d The request signal GA_CMD is sent to the transmitter 202. The request signal GA_CMD can be sent via wireless communication 306 (e.g., Wi-Fi, wireless, Bluetooth, etc.).

[0072] Referring to method 400c, in process 414, the transmitter controller 304 can receive the signal GA_CMD from the receiver controller 302. In process 416, the transmitter controller 304 can determine the error signal eGA based on the received signal GA_CMD. Note that the error signal eGA is used to determine the control signal PWM for the transistor of inverter 108. GA The β factor (via control module 306) determines the relative phase shift between the two legs of inverter 108. Since the phase shift is 180 degrees (2*β = phase shift), full phase shift can be achieved when β = 90. This β factor can also be used to determine the virtual inverter voltage V. inv The virtual inverter voltage V inv This can be used to control the transmitter coil current without utilizing expensive sensors to directly measure the coil current (e.g., at the output of inverter 108). Also refer to process 502 and... Figure 5 In process 418, the transmitter controller 304 can determine the reference bus voltage signal V for the inverter 108 transistor. bus_ref and / or control signal PWM GA Then the transmitter 202 can adjust the voltage signal V. bus_ref (Or else power is output via decision point 420 to stop transmitter 202). This can also be referred to as regulated power.

[0073] Referring to method 400a, receiver controller 302 can determine the input current I of active rectifier 206. 3d This is a result of the adjusted power from transmitter 202. In process 422, the current I can be adjusted according to the following function. 3d With the determined reference current I 3d_ref (See procedure 404) for comparison:

[0074] |I 3d_ref -I 3d |<ε I3d

[0075] In the relationship above, the current I 3d and reference current I 3d_ref The difference between them and the predetermined error value ε I3d A comparison is made. If the difference is less than the error, then in process 424 of method 400b, the modulator Mod...VA Multiple control signals (PWM) can be updated. VA Note the exemplary control signals (PWM) for transistors S7 and S8 of the active rectifier 206. VA It can be based on current I 3d Generated via (multiple) control modules ZCD+PLL and modulator Mod VA (As discussed further below). Exemplary (multiple) control signals PWM VA The error can be based on the output voltage (e.g., in constant voltage mode) or the output current (e.g., in constant current mode). If the difference is greater than or equal to the error, control returns to process 402.

[0076] Referring again to method 400b, in process 426, if the BMS requests a current (e.g., in heating mode, charging mode, etc.), then the output current I will be... o and reference current signal I o_ref The differences between them are compared with the error values ​​as follows:

[0077] |I O_ref -I O |<ε Io

[0078] Alternatively or concurrently, in process 426, if the BMS requests a voltage (e.g., in charging mode, heating mode), the output current Vo and the reference current signal V will be... o_ref The differences between them are compared with the error values ​​as follows:

[0079] |V O_ref -V O |<ε Vo

[0080] Alternatively, in process 426, if the BMS requests power (e.g., in charging mode), the output current P will be... o and reference current signal P o_ref The differences between them are compared with the error values ​​as follows:

[0081] |P O_ref -P O |<ε Po

[0082] Depending on the request, if the comparison is greater than the corresponding error value, control is passed to process 411a. If the comparison is less than the corresponding error value, receiver 204 accordingly provides the requested current I. o or voltage V oThe receiver 204 is stopped via decision point 428 and then fed to the BMS (or otherwise stopped via decision point 428). The control system 300 is advantageous for operation within cost constraints because relatively complex control processes are performed using simple system control facilities. Furthermore, costs can be reduced by eliminating sensors for measuring current (e.g., coil current sensors) and / or voltage at one or more points in the wireless power system.

[0083] Figure 5 This is a diagram of an exemplary wireless power system configured to operate in dual modes, including current measurements at the transmitter resonator coil (by transfer functions G(x)). IV The output 502 indicates (multiple) G IV From the output voltage V of the inverter inv Current I to the transmitter coil 1s The transfer function of G. II From the transmission coil current I 1s Input current I to the active rectifier 3d The transfer function. Note that control system 500 has several components common to control system 300. In the exemplary control system 500, the error signal e GA Based on coil current I 1s The current measurement results.

[0084] Active rectification method

[0085] Figure 6 An exemplary wireless power system is illustrated, including an exemplary active rectifier 602. Note that in some embodiments, transmitter 202 may include a capacitive element connected in series with inductor L3sA and / or inductor L3dB. Receiver 204 may include a capacitive element connected in series with inductor L3sA and / or inductor L3dB. Figure 7A Block diagrams 700a and 700b are used to generate control signals for the transistor(s) of the exemplary active rectifier 206 or 602. (As described above for...) Figure 3 and Figures 4A to 4B The input current I discussed 3d This signal can be provided to a zero-crossing detector 702, whose output represents a sinusoidal current signal I. 3d The zero-crossing signal ZCD. The signal ZCD can be provided to the phase-locked loop (PLL) module 704 (e.g., digital phase-locked loop (DPLL), all-digital phase-locked loop (ADPLL), etc.) to determine the current signal I based on the signal ZCD. 3dThe phase of the phase. Figures 700a and 700b provide alternative implementations of module 704. Module 704a can be a type I phase detector with XOR logic gates. Module 704b can be a type II phase detector with a charge pump. The signal SYNC, representing the extracted phase information, can be provided to the ramp generation module 706. The generated ramp signal and the reference voltage signal V ref The signals are provided to the PWM generator 708. The PWM generator 708 is configured to generate control signals PWM5 and PWM6 (e.g., PWM signals correspondingly for transistors Q5 and Q6, or transistors S7 and S8, respectively) for transistors Q5 and Q6 (e.g., transistors S7 and S8, respectively). VA The exemplary PWM generator 708 and the optional ramp generator 706 can be referred to as modulators (e.g., Modulators). VA In some embodiments, the modulator can be configured to modulate the input current I. 3d The presence of high-current harmonics in the circuit ensures the operational stability of the active rectifier. An exemplary modulator can facilitate zero-voltage switching (ZVS). An exemplary modulator can achieve constant voltage operation as described above.

[0086] Figure 8 It is a collection of various signal graphs that vary over time in a wireless power system 600, including an exemplary active rectifier 602. Figures 9A to 9K The diagram illustrates the time-varying current (dashed line) and / or voltage in an exemplary active rectifier. For the following discussion, note that T0 is the switching period, and the phase shift between signals ZCD and SYNC can be determined as follows:

[0087] t1-t0=0.5·V F ·T0

[0088] Where VF is the normalized voltage of the low-pass filter of the PLL and its range is [0, 1]. (Reference) Figure 8 and Figures 9A to 9K In various embodiments, rectifier 206 or 602 may be configured according to the following method.

[0089] At time t0 A new cycle begins. The PLL is locked and the system operates at steady state (200, 600). The ramp for MOSFET Q5 control is reset to zero.

[0090] RAMP1(t=t0)=0

[0091] MOSFET Q5 and diode D2 are ON; and

[0092] Diode D1 and MOSFET Q6 are OFF.

[0093] At time t1 :I 3d Zero-crossing detection occurs. The output of the zero-crossing detector (ZCD) changes its state.

[0094] RAMP1(t=t1)=0.25-V F / 2

[0095] With the buffer capacitor C sn6 Discharge, V acd The voltage drops to zero (0).

[0096] MOSFET Q5 is ON; and

[0097] Diodes D1 and D2 and MOSFET Q6 are OFF.

[0098] At time t2 : Buffer capacitor C sn6 After discharge, the body diode of MOSFET Q6 is turned on.

[0099] The body diodes of MOSFET Q5 and MOSFET Q6 are ON; and

[0100] Diodes D1 and D2 are OFF.

[0101] At time t3 The control variable V is vacated by the controller (e.g., controller 302). ref Generate the PWM5 turn-off sequence. The effective duty cycle (Deff) of the MOSFET is related to V. ref Related:

[0102] V ref =0.25+D eff / 2

[0103] The effective duty cycle does not include the MOSFET's "synchronous rectification" operation (where the current through the MOSFET is negative and the MOSFET is ON). This is related to the buffer capacitor C. sn5 Charging, voltage V acd Begin its transformation to V LOAD .

[0104] The body diode of MOSFET Q6 is ON; and

[0105] MOSFET Q5, diode D1, and diode D2 are OFF.

[0106] At time t4 With the buffer capacitor C sn5 Charged to voltage V LOAD Diode D1 is turned on.

[0107] The body diodes of diode D1 and MOSFET Q6 are ON; and

[0108] MOSFET Q5 and diode D2 are OFF.

[0109] At time t5 PWM6 turn-on sequence. It is generated from the time sequence t1, with a turn-on delay T. del = t5-t1, this delay is determined empirically (the goal is to maintain ZVS on the MOSFET during transients).

[0110] At time t6 t6 - t0 = T0 / 2. The ramp for MOSFET Q6 control is reset to zero.

[0111] RAMP2(t=t4)=0

[0112] At time t7 :I 3d Zero-crossing detection occurs. The output of the zero-crossing detector changes its state.

[0113] RAMP2(t=t5)=0.25-V F / 2

[0114] With the buffer capacitor C sn5 Discharge, voltage V acd Reduce to zero.

[0115] MOSFET Q6 is ON; and

[0116] Diodes D1 and D2 and MOSFET Q6 are OFF.

[0117] At time t8 : Buffer capacitor C sn5 After being discharged, the body diode of MOSFET Q5 is turned on.

[0118] The body diodes of MOSFET Q6 and MOSFET Q5 are ON; and

[0119] Diodes D1 and D2 are OFF.

[0120] At time t9 The control variable V is vacated by the controller (e.g., controller 302). ref The generated PWM6 shutdown sequence. This is due to the buffer capacitor C. sn6 Charging, voltage V acd Begin its transition to -V LOAD .

[0121] The body diode of MOSFET Q5 is ON; and

[0122] MOSFET Q6, diode D1, and diode D2 are OFF.

[0123] At time t10 With the buffer capacitor C sn6 Charged to voltage V LOAD Diode D2 is switched on.

[0124] The body diodes of diodes D2 and Q5 are ON; and

[0125] MOSFET Q6 and diode D1 are OFF.

[0126] At time t11 PWM5 turn-on sequence. It is generated from sequence t6 and has a turn-on delay T. del =t9-t6.

[0127] At time t12 Same as time t0.

[0128] At time t13 Same as time t1.

[0129] At time t14 Same as time t2.

[0130] At time t15 Same as time t3.

[0131] At time t16 Same as time t4.

[0132] At time t17 Same as time t4.

[0133] Figure 10 This is a flowchart of an exemplary method for active rectification in a wireless power system (e.g., system 200 or 600). In step 1002, the method includes determining a reference value for the current entering a rectifier of a wireless power receiver, wherein the reference value is based on load requirements. In step 1004, the method includes determining a change in the value of the current entering the rectifier based on the reference value. In step 1006, the method includes transmitting a signal representing the change in the value of the current to a wireless power transmitter. In step 1008, the method determines a new value of the current after transmitting the signal. In step 1010, if the new value is within a predetermined range of the value change, at least one transistor in the rectifier is driven with a PWM signal based on the new value.

[0134] Hardware and software implementation methods

[0135] In some examples, some or all of the processes described above can be executed on one or more centralized computing devices. In some examples, some types of processing occur on one device while other types of processing occur on another device. In some examples, some or all of the data described above can be stored in data storage devices hosted on one or more centralized computing devices, or via cloud-based storage. In some examples, some data is stored in one location while other data is stored in another. In some examples, quantum computing can be used. In some examples, functional programming languages ​​can be used. In some examples, electronic storage, such as flash memory, can be used.

[0136] Figure 11 This is a block diagram of an example computer system 1100 that can be used to implement the techniques described in this document. General-purpose computers, network setups, mobile devices, or other electronic systems may also include at least a portion of system 1100. System 1100 includes a processor 1110, memory 1120, storage device 1130, and input / output device 1140. Each of components 1110, 1120, 1130, and 1140 may be interconnected, for example, using system bus 1150. Processor 1110 is capable of processing instructions for execution within system 1110. In some implementations, processor 1110 is a single-threaded processor. In some implementations, processor 1110 is a multi-threaded processor. Processor 1110 is capable of processing instructions stored in memory 1120 or on storage device 1130.

[0137] Memory 1120 stores information in system 1100. In some implementations, memory 1120 is a non-transitory computer-readable medium. In some implementations, memory 1120 is a volatile memory cell. In some implementations, memory 1120 is a non-volatile memory cell.

[0138] Storage device 1130 provides mass storage for system 1100. In some implementations, storage device 1130 is a non-transitory computer-readable medium. In various implementations, storage device 1130 may include, for example, a hard disk drive, an optical disk drive, a solid-state drive, a flash drive, or some other mass storage device. For example, the storage device may store long-term data (e.g., database data, file system data, etc.). Input / output device 1140 provides input / output operations for system 1100. In some implementations, input / output device 1140 may include one or more of the following: a network interface device (e.g., an Ethernet card), a serial communication device (e.g., an RS-232 port), and / or a wireless interface device (e.g., an 802.11 card, a 3G wireless modem, or a 4G wireless demodulator). In some implementations, input / output device may include a driver device configured to receive input data and send output data to other input / output devices, such as a keyboard, printer, and display device 1160. In some examples, mobile computing devices, mobile communication devices, and other devices may be used.

[0139] In some implementations, at least a portion of the methods described above can be implemented by instructions that, upon execution, cause one or more processing devices to perform the processes and functions described above. Such instructions may include, for example, interpreted instructions (such as script instructions), executable code, or other instructions stored on a non-transitory computer-readable medium. Storage device 1130 can be implemented in a distributed manner via a network (such as a server cluster or a widely distributed collection of servers), or it may be implemented in a single computing device.

[0140] Although already Figure 11 While an example processing system has been described herein, embodiments of the subject matter, functional operation, and processes described herein may be implemented in other types of digital electronic circuit systems, in tangibly embodied computer software or firmware, in computer hardware (including the structures disclosed herein and their structural equivalents), or in one or more combinations thereof. Embodiments of the subject matter described herein may be implemented as one or more computer programs, i.e., one or more computer program instruction modules encoded on a tangible, non-volatile program carrier for execution by or control of a data processing apparatus. Alternatively or additionally, the program instructions may be encoded on artificially generated propagated signals, such as machine-generated electrical, optical, or electromagnetic signals, which are generated to encode information for transmission to a suitable receiver device for execution by the data processing apparatus. The computer storage medium may be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or a combination of one or more thereof.

[0141] The term "system" can encompass all kinds of devices, apparatuses, and machines used for processing data, including, for example, programmable processors, computers, or multiple processors or computers. A processing system may include a dedicated logic circuit system, such as a FPGA (Field-Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit). In addition to hardware, a processing system may also include code that creates the execution environment for the computer program in question, such as code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of these.

[0142] Computer programs (also referred to or described as programs, software, software applications, modules, software modules, scripts, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages; and they can be deployed in any form, including as standalone programs or as modules, components, subroutines, or other units suitable for use in a computing environment. A computer program may, but does not necessarily, correspond to a file in a file system. A program may be stored as a part of a file containing other programs or data (e.g., one or more scripts stored in a markup language document), a single file dedicated to the program in question, or multiple coordinating files (e.g., files storing portions of one or more modules, subroutines, or code). Computer programs can be deployed to execute on a single computer or on multiple computers located at a single site or distributed across multiple sites and interconnected via a communication network.

[0143] The processes and logic flows described in this specification can be executed by one or more programmable computers, which execute one or more computer programs to perform functions by manipulating input data and generating output. The processes and logic flows can also be executed by a dedicated logic circuit system, and the device can be implemented as a dedicated logic circuit system, such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit).

[0144] A computer suitable for executing computer programs may include, for example, a general-purpose microprocessor or a special-purpose microprocessor or both, or any other type of central processing unit. Typically, the central processing unit receives instructions and data from read-only memory or random access memory or both. A computer typically includes a central processing unit for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include, or be operatively coupled to, receiving data from or transferring data to one or more mass storage devices (e.g., magnetic disks, magneto-optical disks, or optical disks) for storing data. However, a computer does not necessarily need to have such devices.

[0145] Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, such as semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and memory may be supplemented by or integrated into a dedicated logic circuit system.

[0146] Embodiments of the subject matter described in this specification can be implemented in a computing system that includes back-end components (e.g., as a data server), or middleware components (e.g., an application server), or front-end components (e.g., a client computer having a graphical user interface or a web browser through which a user can interact with an implementation of the subject matter described in this specification), or any combination of one or more such back-end components, middleware components, or front-end components. Components of the system can be interconnected via any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include local area networks (“LANs”) and wide area networks (“WANs”), such as the Internet.

[0147] A computing system may include clients and servers. Clients and servers are typically geographically separated and usually interact through a communication network. The client-server relationship arises from computer programs running on the respective computers and having a client-server relationship with each other.

[0148] While this specification contains numerous specific implementation details, these should not be construed as limiting the scope of possible claims, but rather as descriptions of features of particular embodiments. Certain features described in the context of individual embodiments in this specification may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. Moreover, although features may be described above as functioning in certain combinations and even initially claimed in this way, in some cases one or more features may be removed from the claimed combination, and the claimed combination may involve sub-combinations or variations thereof.

[0149] Similarly, although the operations are described in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order shown or sequentially, or that all illustrated operations be performed to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous. Moreover, the separation of the various system components in the embodiments described above should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated into a single software product or packaged into multiple software products.

[0150] Specific embodiments of this subject matter have been described. Other embodiments are within the scope of the following claims. For example, the actions recited in the claims may be performed in a different order, but still achieve the desired result. As an example, the process depicted in the drawings does not necessarily require the specific order or sequence shown to achieve the desired result. In some implementations, multitasking and parallel processing may be advantageous. Additional steps or stages may be provided from the described process, or steps or stages may be eliminated. Thus, other implementations are within the scope of the appended claims.

[0151] the term

[0152] The wording and terminology used in this article are for descriptive purposes and should not be considered limiting.

[0153] The terms "approximately," "approximately equal to," and other similar phrases (e.g., "the value of X is approximately Y" or "X is approximately equal to Y") used in the specification and claims should be understood to mean that one value (X) is within a predetermined range of another value (Y). Unless otherwise stated, the predetermined range may be plus or minus 20%, 10%, 5%, 3%, 1%, 0.1%, or less than 0.1%.

[0154] Unless explicitly stated otherwise, the indefinite articles “a” and “an” as used in the specification and claims shall be understood to mean “at least one”. The phrase “and / or” as used in the specification and claims shall be understood to mean “one or two” of the elements so combined, i.e., elements that exist together in some cases and separately in others. Multiple elements listed using “and / or” shall be interpreted in the same manner, i.e., “one or more” of the elements so combined. In addition to the elements specifically identified by the “and / or” clause, other elements may optionally be present, whether related to or unrelated to those specifically identified elements. Thus, as a non-limiting example, when used in conjunction with open-ended language such as “comprising,” a reference to “A and / or B” may in one embodiment refer only to A (optionally including elements other than B); in another embodiment, only to B (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements), and so on.

[0155] As used in the specification and claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” should be interpreted as inclusive, that is, including at least one, and also including several elements or more than one in a list of elements, as well as (optionally) other unlisted items. Only when the opposite term is explicitly indicated (such as “only one” or “exactly one”) or when used in a claim, the term “consisting of” will refer to the inclusion of several elements or one element in a list of elements. In general, if preceded by an exclusive term (such as “any,” “one of,” “only one,” or “exactly one”), the term “or” as used should only be interpreted as indicating an exclusive alternative (i.e., “one or another but not both”). “Substantially consisting of” as used in the claims should have the general meaning used in the field of patent law.

[0156] As used in the specification and claims, the phrase "at least one" when referring to a list of one or more elements should be understood to mean at least one element selected from any one or more elements in the list, but does not necessarily include at least one of each element specifically listed in the list, and does not exclude any combination of elements in the list. This definition also allows for the optional presence of elements other than those specifically identified in the list of elements referred to by the phrase "at least one," whether related to or unrelated to those specifically identified elements. Thus, as a non-limiting example, in one embodiment, "at least one of A and B" (or equivalently, "at least one of A or B", or equivalently, "at least one of A and / or B") may refer to at least one (optionally, including more than one) A, with no B (and optionally, including elements other than B); in another embodiment, it may refer to at least one (optionally, including more than one) B, with no A (and optionally, including elements other than A); in yet another embodiment, it refers to at least one (optionally, including more than one) A and at least one (optionally, including more than one) B (and optionally, including other elements), etc.

[0157] The use of “includes,” “contains,” “has,” “includes,” “involves,” and their variations is intended to cover the items and additional items listed thereafter.

[0158] The use of serial numbers such as "first," "second," and "third" in claims to modify a claim element itself does not imply any priority, precedence, or order of action of one claim element relative to another claim element, or any temporal order of the actions of the methods of execution. Serial numbers are merely labels used to distinguish one claim element with a specific name from another claim element with the same name (but using serial numbers), thus differentiating the claim elements.

Claims

1. A method for controlling an active rectifier of a wireless power receiver, the active rectifier comprising a first transistor, a second transistor, a first buffer capacitor coupled in parallel to the first transistor, and a second buffer capacitor coupled in parallel to the second transistor, the method comprising: determining a reference value for current to the rectifier, the reference value being based on a load requirement; determining a required value change of a present input current to the rectifier based on the reference value; transmitting a signal indicative of the desired value change of the present input current to a wireless power transmitter; determining a new value of the present input current after transmitting the signal; When the new value is within a predetermined range of the required value change: Detecting phase information associated with the new value of the present input current, wherein detecting phase information associated with the new value comprises: detecting zero-crossing information associated with the new value of the present input current; and Providing the zero-crossing information to a phase-locked loop module, the module comprising an XOR logic gate or a charge pump; generating a PWM signal based on the detected phase information; and Driving at least one of the first transistor or the second transistor with the generated PWM signal, wherein the method further comprises: setting a ramp signal associated with the second transistor to zero; After detecting the first zero-crossing information, discharging the first buffer capacitor, thereby reducing the input voltage of the active rectifier to zero and turning on the body diode of the first transistor; turning off the second transistor so as to charge the second buffer capacitor to a load voltage of the wireless power receiver; turning on the first transistor; setting a ramp signal associated with the first transistor to zero; After detecting the second zero-crossing information, discharging the second buffer capacitor, thereby reducing the input voltage of the active rectifier to zero and turning on the body diode of the second transistor; turning off the first transistor, thereby charging the first buffer capacitor to the load voltage; and turning on the second transistor; and When the new value is not within the predetermined range, another reference value of the current to the rectifier is determined.

2. The method according to claim 1, further comprising: A request is received from a battery management system for at least one of: a voltage from the wireless power receiver, a current from the wireless power receiver, or a power from the wireless power receiver.

3. The method of claim 1 , wherein transmitting the signal indicative of the desired value change of the present input current to the wireless power transmitter causes a change in power transmitted by the wireless power transmitter to the wireless power receiver; and The new value of the present input current is based on the change in transmitted power. The method of claim 3 , wherein the change in transmitted power is to reduce the power. The method of claim 4 , wherein the change in transmitted power is to reduce the power to zero. The method of claim 3 , wherein the change in transmitted power is to increase the power.

7. The method according to claim 1, further comprising: The new value of the present input current is compared to the predetermined range of the required value change.

8. A controller for controlling an active rectifier of a wireless power receiver, the active rectifier comprising a first transistor, a second transistor, a first buffer capacitor coupled in parallel to the first transistor, and a second buffer capacitor coupled in parallel to the second transistor, wherein the controller is coupled to the rectifier and is configured to perform steps comprising: determining a reference value for current to the rectifier, the reference value being based on a load requirement; determining a required value change of a present input current to the rectifier based on the reference value; transmitting a signal indicative of the desired value change of the present input current to a wireless power transmitter; determining a new value of the present input current after transmitting the signal; When the new value is within a predetermined range of the required value change: Detecting phase information associated with the new value of the present input current, wherein detecting phase information associated with the new value comprises: detecting zero-crossing information associated with the new value of the present input current; and providing the zero-crossing information to a phase-locked loop module, the module comprising (i) an XOR logic gate or (ii) a charge pump; generating a PWM signal based on the detected phase information; Driving at least one of the first transistor or the second transistor with the generated PWM signal, wherein the step further comprises: setting a ramp signal associated with the second transistor to zero; After detecting the first zero-crossing information, discharging the first buffer capacitor, thereby reducing the input voltage of the active rectifier to zero and turning on the body diode of the first transistor; turning off the second transistor so as to charge the second buffer capacitor to a load voltage of the wireless power receiver; turning on the first transistor; setting a ramp signal associated with the first transistor to zero; After detecting the second zero-crossing information, discharging the second buffer capacitor, thereby reducing the input voltage of the active rectifier to zero and turning on the body diode of the second transistor; turning off the first transistor, thereby charging the first buffer capacitor to the load voltage; and turning on the second transistor; and When the new value is not within the predetermined range, another reference value of the current to the rectifier is determined.

9. The controller according to claim 8, wherein the steps further comprise: A request is received from a battery management system coupled to an output of the rectifier for at least one of: a voltage from the wireless power receiver, a current from the wireless power receiver, or a power from the wireless power receiver.

10. The controller of claim 8, wherein the signal representing a change in the required value of the present input current is transmitted to the wireless power transmitter, causing a change in the power transmitted by the wireless power transmitter to the wireless power receiver; and The new value of the present input current is based on the change in transmitted power.

11. The controller of claim 10, wherein the change in transmitted power is to reduce the power.

12. The controller of claim 11, wherein the change in transmitted power is to reduce the power to zero.

13. The controller of claim 10, wherein the change in delivered power is to increase the power.

14. The controller according to claim 8, wherein the steps further comprise: The new value of the present input current is compared to the predetermined range of the required value change.

15. The controller of claim 8, wherein the controller is coupled to the at least one transistor in the rectifier.

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