Active Rectification Control in Wireless Power Systems

Abstract

Active rectification methods and systems for a rectifier of a wireless power system are described herein. An exemplary method may include detecting one or more zero crossings of a current at an input of the rectifier by a zero crossing detector; and determining a first delay time based on at least one wireless power system parameter and the zero crossings. The method may include generating first and second control signals for first and second switches of the rectifier based on the first delay time, respectively; inserting a first dead time between the first control signal and the second control signal; and providing the first and second control signals to the first and second switches, respectively.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application number 202080073256.9, application date August 26, 2020, and invention name “Active Rectification Control in Wireless Power Systems”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 891,959, filed on August 26, 2019, entitled “CONTROL OF ACTIVE RECTIFIER SWITCHES IN WIRELESS POWER SYSTEMS,” the entire contents of which are incorporated herein by reference. Technical Field

[0004] The following disclosure relates to active rectification methods and systems in wireless power systems, and more particularly, to control of active rectification methods and systems in wireless power receivers. Background Art

[0005] Wireless power systems are configured to transmit power to a load (e.g., a battery of an electrical device) without mechanical contact between the transmitter and the receiver. Wireless power receivers of such systems generally include a rectifier to convert oscillating energy into DC for delivery to a load (e.g., a battery) coupled to the receiver. It may be beneficial for the rectifier to operate at high efficiency. Summary of the invention

[0006] An active rectification control method for a wireless power system is disclosed herein.

[0007] In one aspect, the disclosure features an active rectification method for a rectifier of a wireless power system. The method may include detecting one or more zero crossings of a current at an input of the rectifier by a zero crossing detector; and determining a first delay time based on at least one wireless power system parameter and the zero crossings. The method may further include generating first and second control signals for first and second switches of the rectifier based on the first delay time, respectively; inserting a first dead time between the first control signal and the second control signal; and providing the first and second control signals to the first and second switches, respectively.

[0008] Various embodiments of the active rectification method may include one or more of the following features. The method may include: determining a second delay time based on a wireless power system parameter and a zero crossing; generating third and fourth control signals for third and fourth switches of the rectifier based on the second delay time, respectively; inserting a second dead time between the third control signal and the fourth control signal; and providing the third and fourth control signals to the third and fourth rectifier switches, respectively. The third and fourth switches may be coupled to the first and second switches in a full-bridge configuration. The rectifier may be part of a wireless power receiver. The rectifier may be part of a wireless power transmitter.

[0009] The rectifier may include two diodes coupled to first and second switches in a full-bridge rectifier configuration. The first and second switches may be low-side switches of the rectifier. The first and second switches may be coupled to a first rectifier input, and the two diodes may be coupled to a second rectifier input. The first delay time may be determined by a delay block operably coupled to a zero crossing detector. The zero crossing may include a first zero crossing corresponding to a current rise and a second zero crossing corresponding to a current fall. The value of at least one wireless power system parameter may be based on at least one of: (i) an impedance of the rectifier; (ii) a power level transmitted to a load coupled to the wireless power system; or (iii) a coil current of a wireless power receiver including the rectifier.

[0010] In another aspect, the disclosure features an active rectification system for a wireless power system. The system may include: a first switch and a second switch coupled between an oscillating current source and a battery of the wireless power system; and a control system coupled to each of the first switch and the second switch. The control system may be configured to: detect one or more zero crossings of the oscillating current at an input of the rectifier; and determine a first delay time based on at least one wireless power system parameter and the zero crossings. The control system may be further configured to: generate first and second control signals for the first and second switches of the rectifier based on the first delay time, respectively; insert a first dead time between the first control signal and the second control signal; and provide the first and second control signals to the first and second switches, respectively.

[0011] Various embodiments of the active rectification system may include one or more of the following features. The system may include a third switch and a fourth switch coupled between an oscillating current source and a battery of a wireless power system. The control system may be further configured to: determine a second delay time based on a wireless power system parameter and a zero crossing; and generate third and fourth control signals for third and fourth switches of the rectifier based on the second delay time, respectively. The control system may be further configured to insert a second dead time between the third control signal and the fourth control signal; and provide the third and fourth control signals to the third and fourth rectifier switches, respectively. The third and fourth switches may be coupled to the first and second switches in a full-bridge configuration.

[0012] The rectifier may be part of a wireless power receiver. The rectifier may be part of a wireless power transmitter. The rectifier may include two diodes coupled to first and second switches in a full-bridge rectifier configuration. The first and second switches may be low-side switches of the rectifier. The value of at least one wireless power system parameter may be based on at least one of: (i) an impedance of the rectifier; (ii) a power level transmitted to a battery coupled to the wireless power system; or (iii) a coil current of a wireless power receiver including the rectifier.

[0013] In another aspect, the present disclosure features an active rectification method for a wireless power system. The method may include: detecting one or more zero crossings of a current at an input of a rectifier by a zero crossing detector; generating a phase locked loop (PLL) signal based on a rising zero crossing and a falling zero crossing; determining a first delay time based on at least one wireless power system parameter and the zero crossing; generating first and second control signals for first and second switches of the rectifier based on the first delay time and the PLL signal, respectively; inserting a first dead time between the first control signal and the second control signal; and providing the first and second control signals to the first and second switches, respectively.

[0014] In another aspect, the present disclosure features an active rectification method for a wireless power system. The method may include: receiving and / or filtering a current at an input of a rectifier; detecting one or more zero crossings of the current at the input of the rectifier by a zero crossing detector; determining a first delay time based on at least one wireless power system parameter and the zero crossings; generating first and second control signals for first and second switches of the rectifier based on the first delay time, respectively; inserting a first dead time between the first control signal and the second control signal; and providing the first and second control signals to the first and second switches, respectively.

[0015] In another aspect, the present disclosure features an active rectification method for a wireless power system. The method may include: detecting one or more zero crossings of a current at an input of a rectifier by a zero crossing detector; generating a phase locked loop (PLL) signal based on rising zero crossings and falling zero crossings; determining a first voltage signal based on one or more wireless power system parameters; generating first and second control signals for first and second switches of the rectifier based on the PLL signal and the first voltage signal, respectively; inserting a first dead time between the first control signal and the second control signal; and providing the first and second control signals to the first and second switches, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a block diagram of an exemplary wireless power system.

[0017] Figure 2A is a schematic diagram of an exemplary wireless power system employing active rectification.

[0018] Figures 2B to 2C is a schematic diagram of an exemplary wireless power receiver employing active rectification.

[0019] Figure 3A is a schematic diagram of an exemplary wireless power system employing active rectification.

[0020] Figure 3B is a diagram of an exemplary workflow for determining control signals for rectifier switches based on input current.

[0021] Figure 3C is a set of graphs illustrating various signals in generating a control signal that varies over time.

[0022] Figure 3D is a flow chart of an exemplary method for rectifier switch control in a wireless power system.

[0023] Figure 4A is a diagram of an exemplary workflow for determining control signals for rectifier switches based on input current.

[0024] Figure 4B is a set of graphs illustrating various signals in generating a control signal that varies over time.

[0025] Figure 4C is a flow chart of an exemplary method for rectifier switch control in a wireless power system.

[0026] Figure 5A is a diagram of an exemplary workflow for generating control signals for rectifier switches based on input current.

[0027] Figure 5Bis a set of graphs illustrating various signals in generating a control signal that varies over time.

[0028] Figure 5C is a flow chart of an exemplary method for rectifier switch control in a wireless power system.

[0029] Fig. 6A is a diagram of an exemplary workflow for determining a control signal for a rectifier switch based on an input current and an input voltage.

[0030] Figure 6B-6C is a set of graphs illustrating various signals in generating a control signal that varies over time.

[0031] Fig.6D is a flow chart of an exemplary method for rectifier switch control in a wireless power system.

[0032] Figure 7 is a schematic diagram of an exemplary bidirectional wireless power transfer system.

[0033] Figure 8 is a flow chart of an exemplary bidirectional control process.

[0034] Fig. 9 is a schematic diagram of an exemplary inverter-rectifier and a timing diagram illustrating the operation of the inverter-rectifier in an inverter operating mode.

[0035] Fig.10 is a schematic diagram of an exemplary inverter-rectifier and a timing diagram illustrating the operation of the inverter-rectifier in a rectifier operating mode.

[0036] Fig.11 is a block diagram of an example computer system that can be used to implement the active rectification systems and methods described herein. DETAILED DESCRIPTION

[0037] Exemplary embodiments of active rectification systems and methods in wireless power systems are disclosed herein. Specifically, active rectification can be used in a wireless power receiver. Active rectification employs actively controlled switches that are coupled to form a rectifier. The switch may include a transistor (e.g., FET, MOSFET, BJT, IGBT, etc.). In an exemplary wireless power system, an active rectifier may be used to convert an oscillating current (AC) received at a wireless power receiver into a direct current (DC), which may be used to ultimately transfer energy to a load, as further described below. Details of an illustrative embodiment are discussed below.

[0038] Wireless Power System Overview

[0039] Figure 11 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 104, a power source (e.g., AC mains, battery, etc.) provides power to an inverter 108. Additional components may include a power factor correction (PFC) circuit 106 before the inverter stage 108. Inverter 108 drives a transmitter resonator coil and a capacitive component 112 ("resonator") via an impedance matching network 110 (including fixed and / or tunable network components). Transmitter resonator 112 generates an oscillating magnetic field, which induces a voltage and / or current in a receiver resonator 114. Received energy is provided to a rectifier 118 via an impedance matching network 116 (including fixed and / or tunable network components). Ultimately, the rectified power is provided to a load 120 (e.g., one or more batteries of an electric or hybrid vehicle). In some embodiments, the battery voltage level may affect various parameters (e.g., impedance) of wireless power system 100. Thus, the battery voltage level may be received, determined, or measured to be provided as an input to other portions of the wireless power system 100. For example, typical battery voltage ranges for electric vehicles include 200-280V, 200-350V, 200-420V, and the like.

[0040] In some embodiments, one or more components of the transmitter 102 may be coupled to a 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 the receiver 104. In some embodiments, one or more components of the transmitter 102 may be coupled to one or more sensors 124 (e.g., current sensor, voltage sensor, power sensor, temperature sensor, fault sensor, etc.). The controller 122 and the sensors 124 may be operably coupled to a control portion of the transmitter 102 based on feedback signals from the sensors 124 and / or the sensors 128.

[0041] In some embodiments, one or more components of the receiver 104 may be coupled to a controller 126, 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 the transmitter 102. In some embodiments, one or more components of the transmitter 104 may be coupled to one or more sensors 128 (e.g., current sensors, voltage sensors, power sensors, temperature sensors, fault sensors, etc.). The controller 126 and the sensors 128 may be operably coupled to a control portion of the transmitter 102 based on feedback signals from the sensors 128 and / or the sensors 124.

[0042] Examples of wireless power systems can be found in U.S. Patent Application Publication No. 2010 / 0141042, entitled “Wireless energy transfer systems,” published on June 10, 2010, and U.S. Patent Application Publication No. 2012 / 0112535, entitled “Wireless energy transfer for vehicles,” published on May 10, 2012, both of which are incorporated herein by reference in their entirety.

[0043] The exemplary systems and methods disclosed herein may be described with respect to vehicle applications, but may also be applied to any system or device powered by electricity, such as robots, industrial machines, electrical equipment, consumer electronic devices, etc. The high-power wireless power transmitter may be configured to transmit wireless power in applications such as powering and / or charging batteries for vehicles, industrial machines, robots, or electronic devices that rely on high power. For purposes of illustration, the following disclosure focuses on wireless power transmission for vehicles. However, it should be understood that any one or more of the embodiments described herein may be applied to other applications where wireless power may be utilized.

[0044] As used herein, the term "capacitor" or its symbol may refer to one or more electrical components having capacitance (e.g., measured in farads) and / or capacitive reactance (e.g., measured in ohms). For example, a capacitor may refer to one or more capacitors (e.g., in a "bank" of capacitors), which may be on the order of tens, hundreds, etc. of discrete capacitors. Two or more capacitors may be coupled in series or in parallel to achieve a desired capacitance and / or desired capacitive reactance. It should be noted that herein, capacitive reactance may be expressed as a negative value. However, one skilled in the art will recognize that in some conventions, capacitive reactance may also be expressed as a positive value.

[0045] As used herein, the term "inductor" or its symbol may refer to one or more electrical components having inductance (e.g., in Henrys) and / or inductive reactance (e.g., in Ohms). For example, an inductor may refer to one or more discrete inductors or coils. Two or more inductors may be coupled in series or in parallel to achieve a desired inductance and / or a desired inductive reactance. It should be noted that herein, inductive reactance may be expressed as a positive value.

[0046] Although the present disclosure (including the figures) may provide exemplary values ​​for various electrical components, it should be understood that the values ​​of the components may be customized for a particular application. For example, the values ​​of the various electrical components may depend on whether the wireless power transmitter is used to transmit power to charge a vehicle battery (on the order of several kilowatts) or a cell phone battery (typically less than 5 watts).

[0047] Active Rectification in Wireless Power Receivers

[0048] In some embodiments, active rectification may enable a greater degree of control over the power transfer to the output of receiver 104 and / or load 120. In some embodiments, active rectification may enable a more efficient power transfer to the output of receiver 104 and / or load 120. In some embodiments, by employing active rectification in a wireless power receiver, tunable impedance matching components in receiver 104 and / or transmitter 102 may be eliminated. This may have the benefit of reducing the size, weight, and / or cost associated with a wireless power system.

[0049] Figure 2A is a schematic diagram of an exemplary wireless power system 200 utilizing active rectification. The exemplary system 200 includes a wireless power transmitter 202. The exemplary transmitter 202 includes an inverter 206 (e.g., a half-bridge inverter, a full-bridge inverter, etc.) coupled to a filter circuit 207 (which may include, for example, one or more inductive components L3sA, L3sB, one or more capacitive components, etc.). The inverter 206 may include two or more switches (e.g., transistors Q1, Q2, Q3, and Q4). The signals Q1, Q2, Q3, Q4 may be controlled via respective control signals PWM1, PWM2, PWM3, PWM4. The filter 207 may be further coupled to a transmission resonator and / or matching circuit 208 (including capacitors C2s, C1sA, C1sB, and an inductor L1s), as described above.

[0050] In the exemplary system 200, the inductor L1s of the circuit 208 can be inductively coupled to the inductor L1d of the receiving resonator and / or matching circuit 210 (including capacitors C1dA, C1dB, C2d and inductor L1d) to wirelessly transmit power from the transmitter 202 to the receiver 204a. It should be noted that the transmitter coil L1s generates an oscillating magnetic field, which can induce an oscillating current at the receiver coil L1d. This current can have a frequency of, for example, 85kHz. In many cases, due to the inverter 206, the current I3d can include harmonics. In some embodiments, the characteristics of the current I3d (e.g., phase, amplitude, shape, harmonic content, etc.) can be further affected by one or more components of the receiver 204a (e.g., shaping, distortion, etc.). For example, the circuits 210 and 212 can include inductive and / or capacitive components that can change the phase or shape of the current I3d. In some cases, distortion of current I3d can create challenges in operating the rectifier switches, as described further below.

[0051] The exemplary receiver 204a may include a filter circuit 212 (including, for example, one or more inductive components L3dA, L3dB, one or more capacitive components, etc.) coupled to the receive resonator and / or matching circuit 210. The filter circuit 212 may be configured to change the characteristics of the current I3d (e.g., reduce distortion).

[0052] The filter circuit 212 can be coupled to a rectifier 214a (e.g., a half-bridge inverter, a full-bridge inverter, etc.), which can include two or more switches (e.g., transistors Q5, Q6, Q7, and Q8). The exemplary rectifier 214a can be directly or indirectly coupled to a load 216 (e.g., a battery). In some embodiments, a current sensor 218 can determine (e.g., measure, sense, etc.) a characteristic of the current I3d. The current sensor 218 can be coupled at the output of the filter 212 and / or the input of the rectifier 214. For example, the current sensor 218 can determine the phase of the current I3d at the input of the rectifier 214. The sensor signal can be provided to a processor and / or controller (e.g., controller 126) for processing. In some embodiments, the processor and / or controller can generate a control signal (e.g., a PWM signal) based on the current sensor 218 signal for controlling one or more switches of the rectifier 214. The processor and / or controller may provide control signals (e.g., PWM5, PWM6, PWM7, PWM8) to one or more switches (e.g., Q5, Q6, Q7, Q8, respectively) of the rectifier 214. In some embodiments, the current sensor 218 may include a zero crossing detector configured to detect the zero crossing of the current I3d, as described in further detail below. The detector signal may be provided to the controller to determine the control signal for the switch.

[0053] In some embodiments, the control signal can cause the rectifier switch to operate in various modes. The modes can include hard switching and / or soft switching (e.g., zero voltage switching). In some embodiments, the rectifier switch can operate in one mode during a first time period and in another mode during a second time period. In some cases, the switch can alternate or switch between the two modes during a given time period.

[0054] The following non-limiting exemplary wireless power system 200 specifications are referenced herein:

[0055] ●The transmitter coil L1s can be placed on a single or multi-layer ferrite.

[0056] • The system 200 is configured to deliver approximately 11.3 kW of power to the load 216 .

[0057] • The receiver coil L1d may have 15 turns or less, 20 turns or less, 25 turns or less, etc. (eg, approximately 16 turns).

[0058] • Matching can be configured for a voltage range Vbus = 300-900V (eg, 640-840V).

[0059] Figure 2B An alternative embodiment of a wireless power receiver 204b is described that includes an active rectifier 214b. The receiver 204b includes the same or similar components described herein for the receiver 204a. However, the rectifier 214b is a full-bridge active rectifier having diodes D5, D6 in a high-side position and switches Q7, Q8 in a low-side position.

[0060] Figure 2C Another alternative embodiment of a wireless power receiver 204c including an active rectifier 214c is described. Receiver 204c includes the same or similar components described herein for receiver 204a. However, rectifier 214c is a full-bridge active rectifier having (i) diodes D6, D8 coupled between input node 220 and the output of rectifier 214c, and (ii) switches Q5, Q7 coupled between input node 222 and the output of rectifier 214c. In an alternative embodiment, the active rectifier may be a full-bridge active rectifier having (i) switches Q6, Q8 coupled between input node 220 and the output of rectifier 214c (instead of switches Q5, Q7). Figure 2C (ii) diodes D5, D7 (replacing diodes D6, D8 in the input node 222 and the output of the rectifier) ​​coupled between the input node 222 and the output of the rectifier Figure 2C It should be noted that one or more of the following methods may be used to control the switches of the rectifiers 214a, 214b, or 214c.

[0061] First Exemplary Method - Resistive Input Impedance

[0062] Figure 3A is a schematic diagram of an exemplary wireless power system 300 utilizing active rectification. It should be noted that system 300 may include components of system 200 as discussed above (e.g., rectifier 214a, 214b, or 214c). In some embodiments, system 300 may include: a receiver 303 having one or more capacitors C3dA coupled between inductor L3dA and a first input 301a of rectifier 214a; and one or more capacitors C3dB coupled between L3dB and a second input 301b of rectifier 214a.

[0063] Figure 3BAn exemplary workflow 302 corresponding to an exemplary method for determining control signals (eg, PWM5, PWM6, PWM7, PWM8) of rectifier switches (eg, Q5, Q6, Q7, Q8, respectively) based on input current I3d is illustrated. Figure 3C is a set of graphs illustrating various signals in generating a control signal that varies over time. Figure 3D An exemplary method 304 is described for determining a control signal for active rectification in a rectifier that presents a resistive impedance to one or more portions of a wireless power system (e.g., transmitter 202, components between Vbus and arrow 305, etc.). For the sake of clarity and simplicity, the present invention is discussed together herein. Figures 3A to 3D .

[0064] refer to Figure 3B , the current I3d may be input to a zero-crossing detector 306 (eg, of a control system 322). Figure 3C (i) provides an exemplary current I3d. In step 308 of the exemplary active rectification method 304, the detector 306 is configured to detect a zero crossing of the input current I3d. Figure 3C (ii), the detector 306 can output a zero crossing detection signal Vzcd indicating a zero crossing of the current signal I3d. For example, the current I3d has a rising zero crossing at time t0 and a falling zero crossing at time t5. The zero crossing information can be used to synchronize the switching pattern of the Q5, Q6, Q7 and / or Q8 switches with the zero crossing of the I3d current, such as in Figure 3C (iii) and Figure 3C Specifically, the rising edge 310a (at time t0) and the falling edge 310b (at time t5) of the signal Vzcd can be used to control the switching signal PWM pdt5 and PWM pdt7 (As in Figure 3C (iii)) and the switching signal PWM pdt6 and PWM pdt8 (As in Figure 3C (v)) for timing.

[0065] The signal with zero-crossing information (e.g., voltage Vzcd) may be provided to a delay block 312 (e.g., of a control system 322). In step 314, the delay block 312 may determine a first delay time T based on a system parameter (e.g., β as further described below). del1 and the second delay time T del2 The exemplary delay block 312 may be configured to provide one or more time delays according to the following relationship:

[0066] Time delay 1: T del1=(270-β) / 360*T period

[0067] Time delay 2: T del2 =(90+β) / 360*T period -T dead

[0068] Where 0≤β≤90°, T period is a single time segment of the input signal I3d, and time T dead is a fixed amount (e.g., on the order of hundreds of nanoseconds) based on the specifications of the transistors and / or gate drivers used. dead The time delays may be sufficient so that a breakdown condition does not occur during the phase lag and one transistor in a pair conducts at a given time. For example, switch Q5 should not be turned on at the same time as its counterpart switch Q7. As described below, these time delays can be used to generate delayed control signals (e.g., PWM pdt5 、PWM pdt6 、PWM pdt7 、PWM pdt8 ). The delayed control signal may be provided to the dead time compensation block 306.

[0069] Depending on the preferred system optimization, the parameter β may be determined by the controller. In some embodiments, the controller may be configured to generate an equivalent impedance of the rectifier 214 and thus select β to achieve said impedance. In some embodiments, the controller may be configured to maintain the impedance of the rectifier despite changes in battery voltage (at the load 216), and thus select β to achieve maintenance. In some embodiments, the controller may be configured to maintain the power provided to the load 216 within a specific range, and thus select β to achieve maintaining power. In some embodiments, β may be selected to maintain a desired coil current on the receiver side (e.g., in L1d).

[0070] In some embodiments, T del1 It can be 0.5 time period (T period ) to 0.75 time period (T period ). In some embodiments, T del2 It can be 0.25 time period (T period ) to 0.5 time period (T period ). Delay time T del1 It can be used for the control signal of switches Q5 and Q7. The delay time Tdel2 can be used for the control switch of switches Q6 and Q8. It should be noted that switches Q5 and Q7 form a soft switching phase leg, while switches Q6 and Q8 form a hard switching phase leg. Figure 3C In the example described in del1is equal to the difference between time t0 and t6, and the delay time T del2 Equal to the difference between t0 and t3.

[0071] In step 316, the control system 322 (eg, the controller 318 and / or the processor 320 coupled to the switch) may respectively determine the delay time T based on the first delay time T. del1 Generate a first “pre-dead time” control signal PWM for the first rectifier switch Q5 and the second rectifier switch Q7 pdt5 and the second pre-dead time" control signal PWM pdt7 For example, the rising edge 310a and the falling edge 310b of the signal Vzcd are used to generate the signal PWM pdt5 and PWM pdt7 corresponding edges 324a, 324b.

[0072] In step 326, the control system 322 may respectively control the del2 Generate a third “pre-dead time” control signal PWM for the third rectifier switch Q6 and the fourth rectifier switch Q8 pdt6 and the fourth "pre-dead time" control signal PWM pdt8 For example, the rising edge 310a and the falling edge 310b of the signal Vzcd are used to generate the signal PWM pdt6 and PWM pdt8 corresponding edges 328a, 328b.

[0073] In step 328, the dead time insertion block 330 may insert the dead time T dead Insert the first pre-dead time control signal PWM pdt5 The second pre-dead time control signal PWM pdt7 By inserting dead time into the signal PWM pdt5 With PWM pdt7 In between, the control system 322 generates control signals PWM5, PWM7 for the corresponding rectifier switches Q5, Q7. Figure 3C In (iv), arrows 332a and 332b indicate the dead time T between the corresponding edges of the signals PWM5 and PWM7. dead (For example, make T dead = t7-t6 and T dead =t12-t11).

[0074] In step 334, the dead time insertion block 330 may insert the dead time T dead Insert the third pre-dead time control signal PWM pdt6 With the fourth pre-dead time control signal PWM pdt8By inserting dead time into the PWM signal pdt6 With PWM pdt8 In between, the control system 322 generates control signals PWM6, PWM8 for the corresponding rectifier switches Q6, Q8. Figure 3C In (vi), arrows 336a and 336b indicate the dead time T between the edges of signals PWM6, PWM8. dead (For example, make T dead = t4-t3 and T dead =t9-t8).

[0075] In step 338, the control system 322 may provide control signals to the respective rectifier switches. In an example of a full-bridge rectifier having four switches (e.g., as in rectifier 214a), a control signal PWM5 is generated for switch Q5; a control signal PWM6 is generated for switch Q6; a control signal PWM7 is generated for switch Q7; and a control signal PWM8 is generated for switch Q8. In another example, for a rectifier having two high-side diodes and two low-side switches Q7 and Q8 (e.g., as in rectifier 214b), only control signals PWM7 and PWM8 are provided to respective switches Q7 and Q8. In yet another example, for rectifier 214c, control signals PWM5 and PWM7 are provided to respective switches Q5 and Q8.

[0076] For an exemplary receiver 303 of system 300 having the specifications provided above and utilizing workflow 302, the value of the filter inductor L3dA in system 300 may be approximately 35 μH. A series compensation capacitor may be used to maintain the same impedance at 85 kHz as a 7 uH inductor.

[0077] Second Exemplary Method—Resistive Input Impedance

[0078] Figure 4A A workflow 400 is illustrated of an exemplary method for generating a control signal for a rectifier switch based on an input current I3d. Figure 4B is a set of graphs illustrating various signals in generating a control signal that varies over time. Figure 4C An exemplary method 402 is described for generating a control signal for a rectifier that presents a resistive impedance to one or more portions of a wireless power system (eg, a transmitter 202, components between Vbus and arrow 305, etc.). Figures 4A to 4C .

[0079] refer to Figure 4A , the current I3d may be provided to a zero crossing detector 406 (eg, of the processor 320). Figure 4B(i) provides an exemplary current I3d. In step 404 of the exemplary method 402, the zero crossing detector 406 can detect the time t of the rising input current signal I3d. 0 The rising zero crossing at the time t of the falling input current signal I3d 5 The zero-crossing detector 406 can output a voltage signal Vzcd having zero-crossing information of the current signal I3d.

[0080] In step 408, a phase delay lock (PLL) block 410 may generate a PLL signal based on the rising zero crossing and falling zero crossing of the current I3d. Block 410 outputs a PLL signal "SYNC", such as Figure 4B (iii) is described, the signal is a signal "synchronized" with the zero-crossing signal Vzcd, so that the signal SYNC is in phase with the signal Vzcd. In some embodiments, the SYNC signal can be a copy of the voltage signal Vzcd. In some embodiments, the SYNC signal can have the same phase and / or frequency as the signal Vzcd, but the magnitude is different from the voltage signal Vzcd. For example, the rising edge of Vzcd corresponds to the rising edge of SYNC at time t0 (indicated by arrow 412a), and the falling edge of Vzcd corresponds to the falling edge of SYNC at time t5 (indicated by arrow 412b).

[0081] In step 413, the delay block 414 may determine a first delay time T based on a system parameter (eg, β as described further below). del1 and the second delay time T del2 The delay block 414 may generate one or more time delays according to the following relationship:

[0082] Time delay 1: T del1 =(270-β) / 360*T period

[0083] Time delay 2: T del2 =(90+β) / 360*T period -T dead

[0084] Where 0≤β≤90°, T period is a single time segment of the input signal I3d, and time T dead is a fixed quantity based on the specifications of the transistor and / or gate driver. dead There may be enough that a breakdown condition does not occur during the phase lag and one transistor in a pair conducts at a given time. For example, switch Q5 is not turned on at the same time as its counterpart switch Q7. The delayed signal may be provided to the dead time compensation block 428.

[0085] Depending on the preferred system optimization, parameter β may be determined by the controller. In some embodiments, the controller may be configured to produce an equivalent impedance of rectifier 214, and thus β is selected to achieve said impedance. In some embodiments, the controller may be configured to maintain the impedance of the rectifier despite changes in battery voltage (at load 216), and thus β is selected to achieve maintenance. In some embodiments, the controller may be configured to maintain the power provided to load 216 within a certain range, and thus β is selected to achieve maintained power. For Figure 4B In the example provided in , the parameter β is chosen to be 47 degrees.

[0086] In some embodiments, T del1 It can be 0.5 time period (T period ) to 0.75 time period (T period ). In some embodiments, T del2 It can be 0.25 time period (T period ) to 0.5 time period (T period ). Delay time T del1 Can be used as control signal for switches Q5 and Q7. Delay time T del2 A control switch can be used for switches Q6 and Q8. Note that switches Q5 and Q7 form a soft-switched phase leg, while switches Q6 and Q8 form a hard-switched phase leg. Figure 4B In the example described in del1 is equal to the difference between time t0 and t6, and the delay time T del2 Equal to the difference between t0 and t3.

[0087] In step 416, the delay block 414 may respectively determine the delay time based on the PLL signal SYNC and the first delay time T del1 Generate a "pre-dead time" first control signal PWM for the first rectifier switch Q5 and the second rectifier switch Q7 respectively pdt5 and the second control signal PWM of the "pre-dead time" pdt7 For example, the rising edge 420a and the falling edge 420b of the signal SYNC are used to generate the signal PWM pdt5 and PWM pdt7 edges 420a, 420b.

[0088] In step 422, the delay block 414 may respectively determine the delay time based on the PLL signal SYNC and the second delay time T del2 Generate a "pre-dead time" third control signal PWM for the third rectifier switch Q6 and the fourth rectifier switch Q8 respectively pdt6 and the fourth control signal PWM of the "pre-dead time" pdt8For example, the rising edge 412a and the falling edge 412b of the signal SYNC are used to generate the signal PWM pdt6 and PWM pdt8 edges 424a, 424b.

[0089] In step 426, the dead time compensation block 428 may respectively dead Insert "pre-dead time" first control signal PWM pdt5 The second control signal PWM with "pre-dead time" pdt7 Between. Figure 4B The dead time insertion is illustrated in (v). By inserting the dead time between time t6 and time t7, the control system 322 generates control signals PWM5, PWM7 for the respective rectifier switches Q5, Q7. Figure 4B In (v), arrows 430a, 430b indicate the dead time T between the corresponding edges of signals PWM5, PWM7. dead (For example, make T dead = t7-t6 and T dead =t11-t12).

[0090] In step 432, block 428 may respectively set the dead time T dead Insert a "pre-dead time" third control signal PWM pdt6 The fourth control signal PWM with the "pre-dead time" pdt8 Between. Figure 4B The dead time insertion is described in (vii). By inserting the dead time between times t3 and t4, the control system generates control signals PWM6, PWM8 for the respective rectifier switches Q6, Q8. Figure 4B In (vii), arrows 434a, 434b indicate the dead time T between the respective edges of signals PWM6, PWM8. dead (For example, make T dead = t4-t3 and T dead =t9-t8).

[0091] In step 434, the control system 322 may provide control signals (e.g., PWM5, PWM6, PWM7, and PWM8) to the respective rectifier switches (e.g., Q5, Q6, Q7, and Q8, respectively). In an example of a full-bridge rectifier having four switches (e.g., as in rectifier 214a), a control signal PWM5 is generated for switch Q5; a control signal PWM6 is generated for switch Q6; a control signal PWM7 is generated for switch Q7; and a control signal PWM8 is generated for switch Q8. In another example, for a rectifier having two high-side diodes and two low-side switches Q7 and Q8 (e.g., as in rectifier 214b), only control signals PWM7 and PWM8 are provided to respective switches Q7 and Q8. In yet another example, for rectifier 214c, control signals PWM5 and PWM7 are provided to respective switches Q5 and Q8.

[0092] For the exemplary receiver 204 of the system 200 having the specifications provided above, the value of the filter inductors L3sA, L3sB in the method 402 may be approximately 14 μH. It should be noted that the value of the filter inductors L3sA, L3sB of the method 402 is approximately five times smaller than the value of the filter inductors L3sA, L3sB of the method 304. This may result in a reduced footprint (e.g., cost, volume, etc.) and / or cost for a system employing the method 402.

[0093] Third Exemplary Method - Capacitive Input Impedance

[0094] Figure 5A A workflow 500 corresponding to an exemplary method for generating a control signal for a rectifier switch based on an input current I3d is illustrated. Figure 5B is a set of graphs illustrating various signals in generating a control signal that varies over time. Figure 5C An exemplary active rectification method 502 is described in a rectifier that presents a capacitive impedance to one or more portions of a wireless power system (eg, transmitter 202, components between Vbus and arrow 305, etc.). Figures 5A to 5C .

[0095] In step 504, the sensor 506 may receive an input current I3d. In some embodiments, the sensor 506 may include a filter (e.g., a bandpass filter, a low-pass filter, a high-pass filter, etc.). In a preferred embodiment, the exemplary sensor 506 includes a bandpass filter characterized by the following transfer function:

[0096]

[0097] where ω 0 =2* π / T period and Qf is the quality factor of the filter. Filtering of the current I3d can stabilize the modulator and thereby achieve a stable output control (PWM) signal. The filtered current signal I3dmf is then provided to the zero crossing detector 508.

[0098] In step 510, the zero crossing detector 508 may detect the rising zero crossing of the filtered current signal I3dmf and the falling zero crossing of the filtered current signal I3dmf. The detector 508 may generate an output signal ZCD (eg, voltage Vzcd and / or current Izcd) having zero crossing information. Figure 5B As illustrated in (iii), edge 512a of signal ZCD corresponds to a rising zero crossing of signal I3dmf (at time t0) and edge 512b of signal ZCD corresponds to a falling zero crossing of signal I3dmf (at time t4).

[0099] In step 514, the delay block 516 may determine the delay time T based on system parameters (eg, β as described further below). del1 The delay block 516 may generate one or more time delays according to the following relationship:

[0100] Time delay: T del1 =(270-β) / 360*T period

[0101] Where 0≤β≤90°, T period is a single time period of the input signal ZCD, and time T dead is a fixed quantity based on the specifications of the transistor and / or gate driver. dead There can be enough that no breakdown occurs during the phase lag and only one transistor in a pair is conducting at a given time. For example, switch Q5 is not turned on at the same time as its partner switch Q7. The delayed signal can be PWM pdt5 、PWM pdt7 Provided to dead time compensation block 518 .

[0102] Depending on the preferred system optimization, parameter β may be determined by the controller. In some embodiments, the controller may be configured to produce an equivalent impedance of the rectifier 214, and thus β is selected to achieve said impedance. In some embodiments, the controller may be configured to maintain the impedance of the rectifier constant despite changes in battery voltage (at the load 216), and thus β is selected to achieve maintenance. In some embodiments, the controller may be configured to maintain the power provided to the load 216 within a certain range, and thus β is selected to achieve maintenance power. Figure 5B In the example provided in , the parameter β is selected to be 75 degrees.

[0103] In step 520, the delay block 516 can be based on the delay time T del1 Generate a "pre-dead time" first control signal PWM for the first rectifier switch Q5 and the second rectifier switch Q7 respectively pdt5 and the second control signal PWM of the "pre-dead time" pdt7 .exist Figure 5B In the example described in del1 = is equal to the difference between time t0 and time t5. For example, the rising edge 512a and the falling edge 512b of the signal ZCD are used to generate the signal PWM pdt5 and PWM pdt7 edges 522a, 522b.

[0104] In step 524, the dead time insertion block 526 may include inserting the dead time T dead Inserted between the "pre-dead time" first control signal and the "pre-dead time" second control signal. By inserting the dead time between time t5 and t6, the control system 322 generates the control signal PWM for the corresponding rectifier switch Q5, Q7 pdt5 and PWM pdt7 Specifically, arrows 528a, 528b indicate Figure 5B The dead time T between the edges of the signals PWM5 and PWM7 in the graph in (v) dead It should be noted that the commutation of the diode half bridge (eg, diodes D6, D8) occurs between times t3 and t7, such that t7-t3=T period / 2.

[0105] In step 530 , the control system 322 may provide control signals PWM5 , PWM7 to respective rectifier switches Q5 , Q7 (eg, of the rectifier 214 c ).

[0106] One advantage is that the exemplary method 502 can achieve the use of smaller inductors at the filter inductors L3sA, L3sB, thereby reducing the physical size of the receiver 204. The exemplary method 502 can also achieve higher efficiency compared to methods that include active control of the four switches (e.g., Q5, Q6, Q7, and Q8) of the rectifier 214.

[0107] Fourth Exemplary Method - Phase Shift Control

[0108] Fig. 6A Description is used to control the input current I3d and the input voltage V AC Workflow 600 of an exemplary method for generating control signals for rectifier switches by relative phase shift between Vacd and Vacd. Figures 6B to 6Cis a set of graphs illustrating control signals varying over time according to the generation of workflow 600 . Fig.6D A method 602 for generating a control signal according to the workflow 600 is described. It should be noted that the control scheme of the method 602 can be implemented in the mixed signal or digital domain. For the sake of clarity and simplicity, the control schemes of the method 602 are discussed together in this article. Figures 6A to 6D .

[0109] refer to Fig. 6A , the current I3d can be input to a zero-crossing detector 604 (e.g., of the control system 322). Figure 6B (v) provides an exemplary current I3d. In step 606, the detector 604 is configured to detect the zero crossing of the input current I3d. Figure 6B (i), the detector 604 may output a zero-crossing detection signal Vzcd indicating a zero-crossing of the current signal I3d. As described herein for other methods, the zero-crossing information may be used to synchronize the switching pattern of switches Q5, Q6, Q7, and / or Q8 with the current zero-crossing.

[0110] In step 608, a phase delay lock (PLL) block 610 may generate a PLL signal based on the rising zero crossing and falling zero crossing of the current I3d. Block 610 outputs a PLL signal "SYNC", such as Figure 6B (iii) is described, the signal is a signal "synchronized" with the zero-crossing signal Vzcd, so that the signal SYNC is in phase with the signal Vzcd. In some embodiments, the frequency of the SYNC signal can be at least twice the frequency of the voltage signal Vzcd. In some embodiments, the SYNC signal can have a magnitude different from that of the voltage signal Vzcd. For example, the rising edge of Vzcd corresponds to the falling edge of SYNC (indicated by arrow 612a), and the falling edge of Vzcd corresponds to the rising edge of SYNC (indicated by arrow 612b), so that one period of the signal Vzcd corresponds to two periods of the signal SYNC.

[0111] In step 614, a ramp generation block 616 (eg, of the control system 322) may generate at least one ramp signal Vramp based on the output PLL signal. The ramp signal Vramp is used to generate a PWM signal with the aid of Vdc1 and Vdc2 defined by the following relationship:

[0112]

[0113]

[0114] where parameter β is chosen to control the resistive impedance of the rectifier and is chosen based on the desired system optimization (as described above), and parameter is chosen to control the capacitive impedance of the rectifier. Figures 6B to 6C In the example provided in , for the exemplary system 200 configured to deliver 8.3 kW to the battery 216 , the parameter β=70 and the parameter

[0115] In step 618, the PWM generator 620 (eg, of the control 622) may generate a pre-dead time PWM signal PWM for switches Q5, Q6, Q7, Q8 based on the signals Vdc1 and Vdc2. pdt5 、PWM pdt6 、PWM pdt7 、PWM pdt8 In some embodiments, a control system (eg, a modulator of system 322 ) may modulate signals Vdc1 and Vdc2 to form a control signal (eg, a pre-dead-time PWM signal).

[0116] The frequency of the pre-dead time PWM signal is divided in the divider block 622. In some embodiments, the frequency is divided by a factor of 2. In some embodiments, the frequency is divided by a factor greater than 2 (eg, 2.5, 3, 4, etc.).

[0117] In step 624, the dead time compensation block 626 can calculate the dead time T dead Insert the pre-dead time first control signal PWM pdt5 The second control signal PWM with the pre-dead time pdt7 By inserting the dead time, the control system 322 generates control signals PWM5, PWM7 for the corresponding rectifier switches Q5, Q7.

[0118] In step 628, block 626 may calculate the dead time T dead Insert the pre-dead time third control signal PWM pdt6 The fourth control signal PWM with the "pre-dead time" pdt8 By inserting the dead time, the control system generates control signals PWM6, PWM8 for the corresponding rectifier switches Q6, Q8.

[0119] In step 630, the control system 322 may provide control signals (e.g., PWM5, PWM6, PWM7, and PWM8) to the respective rectifier switches (e.g., Q5, Q6, Q7, and Q8, respectively). In an example of a full-bridge rectifier having four switches (e.g., as in rectifier 214a), a control signal PWM5 is generated for switch Q5; a control signal PWM6 is generated for switch Q6; a control signal PWM7 is generated for switch Q7; and a control signal PWM8 is generated for switch Q8. In another example, for a rectifier having two high-side diodes and two low-side switches Q7 and Q8 (e.g., as in rectifier 214b), only control signals PWM7 and PWM8 are provided to respective switches Q7 and Q8. In yet another example, for rectifier 214c, control signals PWM5 and PWM7 are provided to respective switches Q5 and Q8.

[0120] Application in bidirectional wireless power transmission

[0121] In various embodiments, the active rectification systems and methods described herein can be used in a bidirectional wireless power system. For example, the wireless power system can be configured so that wireless power is transmitted from a transmitter to a receiver (also referred to as "unidirectional"). In some cases, the wireless power system can be configured so that wireless power is transmitted from a first device to a second device (e.g., from a transmitter to a receiver) and / or from a second device to a first device (e.g., from a receiver to a transmitter). Examples of bidirectional wireless power systems and methods can be found in U.S. Publication No. 2019 / 0006836, entitled "Protection and control of wireless power systems," published on January 3, 2019, and U.S. Publication No. 2020 / 0094696, entitled "Wireless power transmission in electric vehicles," published on March 26, 2020.

[0122] Figure 7A schematic diagram of an exemplary two-way wireless power system 700 is shown. The schematic diagram depicts a transmitter (Tx) side wireless power device 700a and a receiver (Rx) side wireless power device 700b. As described above, for situations similar to a one-way wireless power system (e.g., system 200 or 300), the Tx side wireless power device 700a is typically operated as a wireless power transmitter. When used in the context of a wireless power device coupled to an electric vehicle or other mobile vehicle, the Tx side device 700a may also be referred to as a ground assembly (GA) or a GA side device. However, as discussed below, in a two-way system, the Tx side typically refers to a wireless power device coupled to or configured to be coupled to a fixed power source or load such as a power grid, an AC generator, etc. In addition, the Tx side system is typically capable of handling higher power, voltage, or current transients than the Rx side wireless power device 700b. On the other hand, for situations similar to a one-way wireless power transfer system (e.g., system 200 or 300), the Rx side wireless power device 700b is typically operated as a wireless power receiver. However, as discussed below, in a two-way system, the Rx side generally refers to a wireless power device that is coupled to or configured to be coupled to a mobile (e.g., typically more limited) power source or load, such as a battery or battery-powered device (e.g., a computing device or an electric vehicle). When used in the context of a wireless power device coupled to an electric vehicle or other mobile vehicle, the Rx-side wireless power device 700b may also be referred to as a vehicle assembly (VA) or a VA-side device.

[0123] In the exemplary bidirectional system 700, both the Tx side device 700a and the Rx side device 700b include an inverter-rectifier 702. The inverter-rectifier 702 may include a bridge configuration of a switching element and / or a diode. For example, the inverter-rectifier 702 may include an active switching element such as a MOSFET, which allows the inverter-rectifier 702 to operate as an inverter or rectifier in a bidirectional system. As discussed in more detail below, the operating mode (also referred to herein as "operating characteristic") of the inverter-rectifier 702 may be controlled based on the mode of the PWM control signal supplied to the switching element. In some embodiments, the inverter-rectifier 702 may operate according to one or more active rectification methods (e.g., methods 304, 402, 502, and / or 602) described herein.

[0124] The system 700 is capable of powering a load (e.g., a battery of a vehicle) by transmitting power in a first direction (e.g., a normal power flow direction from the transmitter 700a to the receiver 700b), while disconnecting the power input to the transmitter 700a. Alternatively, the system 700 can provide power in a second direction (e.g., a reverse power flow direction), such as supplying power from a battery of an electric vehicle coupled to the Rx-side device 700b to a power grid coupled to the Tx-side device 700a. As another example, the bidirectional system 700 can be used to power a home from a battery in an electric vehicle parked in a garage during a power outage.

[0125] Where a single component including a resistor, inductor, and capacitor is shown, a component group including components in series and / or parallel may be utilized. Where a tunable component is shown, a fixed component may be included in series and / or parallel with the tunable component. In some embodiments, controllers 122a and 122b may be combined in a single controller 720. Likewise, in some embodiments, controllers 126a and 126b may be combined in a single controller 740.

[0126] In some embodiments, controllers 720 and 740 include a bidirectional manager. The bidirectional manager coordinates the configuration of different hardware and software components of the wireless power device (e.g., 700a or 700b) according to the direction of power flow as indicated by the operating characteristics assigned to the device. For example, the operating characteristics of INV indicate that the inverter-rectifier is operating as an inverter, and therefore the wireless power device 700a / 700b is operating as a transmitter. Similarly, for example, the operating characteristics of REC indicate that the inverter-rectifier is operating as a rectifier, and therefore the wireless power device 700a / 700b is operating as a receiver. The bidirectional manager also coordinates the transition from one direction of power flow to the opposite direction of power flow. For example, the bidirectional manager of the Rx side device 700b can communicate with the bidirectional manager of the Rx side device 700a via a wireless communication link 750 (e.g., a Wi-Fi link) to coordinate power reversal. The bidirectional manager can be implemented as a separate controller within each device 700a / 700b or in software.

[0127] More specifically, the various hardware and software components of the system may have different operating set points, modes, and / or operating ranges depending on the power flow direction, and thus the operating characteristics of the wireless power device 700a / 700b. The various operating set points, modes, and / or operating ranges may be stored in memory or in hardware. Each component of the system (e.g., inverter-rectifier 702, tunable matching network (TMN) 703, and other components) including various controllers, filters, communication systems, and / or protection systems may exhibit different "operating characteristics" depending on the power flow direction.

[0128] The bidirectional manager of the wireless power device can assign appropriate characteristics based on the expected direction of power flow through the entire wireless power system 700 at system startup and / or during power flow conversion. For example, upon receiving a command to switch from one operating mode of the system to another operating mode (e.g., by connecting to any or all controllers, on either or both sides of the system, or outside the system, such as an operator interface and / or user interface on a network, grid, or mobile device), the bidirectional manager can assign corresponding operating characteristics to various component controllers (e.g., 122a, 122b, 126a, and 126b). Each controller can use the assigned operating characteristics to identify and load appropriate operating procedures or software code to control the associated components of the wireless power transfer device 700a / 700b. For example, when the inverter-rectifier controller is assigned the operating characteristics of the inverter (e.g., INV), the controller will load software code to generate a PWM control signal pattern to operate the inverter-rectifier switching elements to generate an AC output signal from a DC input signal. On the other hand, when the inverter-rectifier controller is assigned the operating characteristics of a rectifier (eg, REC), the controller will load software code to generate a PWM control signal pattern to operate the inverter-rectifier switching elements to rectify the AC input signal into a DC output signal.

[0129] In addition, the bidirectional manager can provide power requirements, power flow direction, select appropriate software code blocks and assign characteristics to sub-controllers or other controllers. The bidirectional manager can determine recoverable or unrecoverable errors, depending on the system side where the controller is located and the operating characteristics adopted by the controller for the system components. Operating characteristics can be assigned based on the expected power flow direction, such as vehicle-to-grid (V2G) power flow or grid-to-vehicle (G2V) power flow. In addition, the bidirectional manager can determine the recovery time and / or mode of these errors, and / or clear the errors when they are recovered, so no user intervention is required. The bidirectional manager can communicate with the user, the controller on the other side of the system (e.g., the bidirectional manager on the other side of the system).

[0130] The bidirectional manager may receive notifications of errors from components of the wireless power system and may distribute error messages to other components of the wireless power system directly through the bidirectional manager or upon a callback request from the component.

[0131] The bidirectional manager may receive communications from components of the wireless power system (e.g., from components from the other side of the system via Wi-Fi). The bidirectional manager may satisfy component callback requests for messages related to the component, or may dispatch messages to related components. The bidirectional manager may control (including dynamically) the permissions of components of the wireless power system to receive and send error and communication messages. The bidirectional manager may be responsible for controlling the components of the wireless power system during the transition phase, including handling any error conduction caused by the change in power transfer direction (V2G and G2V transition). For example, the bidirectional manager may supervise the shut-down of power, confirm that the power has been fully or partially shut down, and sequence the components of the system to turn on (while assigning characteristics to the components).

[0132] As an example, a bidirectional manager on a transmitter controller receives a command to turn on power from idle, the bidirectional manager can assign G2V features to various controllers and hardware in the system. Upon receiving a communication to change the direction of power transfer, the bidirectional manager communicates between the transmitter and the receiver to change the direction of power transfer. The bidirectional manager can be responsible for handling any errors generated by the change in power transfer direction, including during power down in the first direction and power up in the second direction. When the error is cleared, the bidirectional manager can assign the feature to the controller, for example, by selecting a subset of instructions from a non-transitory computer readable medium, or causing the controller to select a subset of instructions.

[0133] In some embodiments, each controller of the system (eg, a dedicated inverter-rectifier processor, or a dedicated TMN processor, or a dedicated transmitter or receiver processor) may include a bidirectional manager. The bidirectional manager may operate as a top-level manager.

[0134] In general, distributing features to components / controllers can support modular, non-redundant parts, code, and memory, and enable faster real-time switching from G2V (grid-to-vehicle power flow) to V2G (vehicle-to-grid power flow) and from V2G to G2V.

[0135] Figure 8A flow chart depicting an exemplary bidirectional control process 800 that may be performed according to an embodiment of the present disclosure. The example process 800 may be implemented, for example, by an example wireless power system disclosed herein. For example, the process 800 may be performed between a bidirectional manager of a transmitter wireless power device 700a and a bidirectional manager of a receiver wireless power device 700b. The process 800 shows a primary side operation 802 and an auxiliary side 804 operation that are divided. Generally speaking, the primary side operation 802 is performed by the receiver wireless power device 700b, while the auxiliary side operation 704 is performed by the Tx side wireless power device 700a. For example, the receiver (or device side) wireless power device 700b may typically be coupled to a smaller capacity or more limited power source or load. Implementing the receiver wireless power device 700b as a primary device may provide more precise control of the bidirectional control process 800 to prevent exceeding possible lower operating limits of the Rx side system or its load / source. In some examples, the example process 800 may be provided by one or more computer executable programs executed using one or more computing devices, processors, or microcontrollers. For example, the example process 800 or portions thereof may be provided by one or more programs executed by control circuitry of the wireless power devices 700a, 700b.

[0136] The primary device initiates a power flow conversion within the wireless power system. The initiation may be prompted by a user input, or in some embodiments by an automatic power conversion determination prompt performed by the primary device (806). For example, the primary device may determine the shifted power flow based on various criteria, including but not limited to the charge state of the battery, the time of day, and the availability and / or demand of grid power. For example, the Rx-side wireless power device 700b may be configured to initiate a power flow reversal process when the connected battery is above a threshold charge level and a grid power loss occurs. As another example, the Rx-side wireless power device 700b may be configured to initiate a power flow reversal process when the connected battery is above a threshold charge level and during a preset time of day. For example, the Rx-side wireless power device 700b may be configured to reverse the power flow in order to provide supplemental power to the home during peak load periods of the power grid (e.g., high demand periods and / or high energy price periods, such as at night). In some embodiments, the secondary device may determine when to initiate the power flow conversion, but will perform an additional step of requesting the initiation of the power flow conversion from the primary device.

[0137] The primary device sends an instruction to the secondary device to reverse the direction of power flow (808). In response to the instruction, the secondary device reconfigures to operate in the power flow direction opposite to its current operation (810). For example, if the secondary device is operating as a transmitter, the secondary device will be reconfigured to operate as a receiver. If the secondary device is operating as a receiver, the secondary device will be reconfigured to operate as a transmitter. For example, the bidirectional manager of the secondary device can coordinate the operation of the controller within the secondary device to shut down the power flow in the current direction by, for example, ensuring the operation of the inverter-rectifier, shifting the switch to disconnect the load / power source (as appropriate), switching the bypass switch to dissipate the residual current within the secondary device, or a combination thereof.

[0138] The auxiliary device assigns new operating characteristics according to the new power flow direction (812). For example, the bidirectional manager of the auxiliary device assigns the new operating characteristics to the corresponding controllers within the auxiliary device according to the new power flow direction. The bidirectional power manager can assign the new operating characteristics by switching a flag bit (e.g., TMN_SIDE discussed in more detail below) to indicate operation as a transmitter / inverter or operation as a receiver / rectifier.

[0139] In response to the new operating characteristic assignment, various auxiliary device controllers can reconfigure their respective operations. For example, a controller can load a control algorithm (e.g., a software code block) to perform operations according to the new power flow direction. For example, a TMN controller can reset the TMN and load control code to generate appropriate TMN control signals to operate according to the new power flow direction. The TMN may need to adjust set points (e.g., impedance values, impedance adjustment steps, and / or protection schemes) to accommodate power transfer in the new direction or to prepare for power ramping in the new direction, or both. For example, power flow in V2G mode may typically be lower than power flow in G2V mode, for example due to asymmetry between the GA and VA side resonator coils and / or discharge constraints on the battery. Therefore, the TMN and / or inverter-rectifier set points may be different for operation in V2G mode versus G2V mode.

[0140] The auxiliary device (e.g., an inverter controller of the auxiliary device) may control the inverter-rectifier operation according to the new operating characteristics (814). For example, the inverter-rectifier controller may load an appropriate algorithm to generate PWM control signals to operate as an inverter when the auxiliary device is a transmitter and to operate as a rectifier when the auxiliary device is a receiver. Fig. 9 and 10 Specific inverter and rectifier operations are described in more detail.

[0141] The auxiliary device sends a reply indicating the status of its reconfiguration to the primary device (816). When the auxiliary device indicates that its reconfiguration is still in progress or is paused, the primary device waits and / or resends the instruction 808. By the primary device waiting for confirmation that the auxiliary device has completed updating its operating characteristics, the process 800 can provide safer and more robust operation. For example, it can prevent power flow from starting or reversing in the event that the characteristics assigned to the auxiliary device or the primary device do not match. When the auxiliary device indicates that its reconfiguration is complete, the primary device reconfigures to operate in the power flow direction opposite to its current operation (818). For example, if the primary device is operating as a transmitter, the primary device will reconfigure to operate as a receiver. If the primary device is operating as a receiver, the primary device will reconfigure to operate as a transmitter. For example, the bidirectional manager of the primary device can coordinate the operation of the controller within the auxiliary device to shut down the power flow in the current direction by, for example, ensuring the operation of the inverter-rectifier, shifting the switch to disconnect the load / power source (as appropriate), switching the bypass switch to dissipate the residual current within the auxiliary device, or a combination thereof.

[0142] The primary device assigns new operating characteristics according to the new power flow direction (820). For example, the bidirectional manager of the primary device assigns the new operating characteristics to the corresponding controllers within the primary device according to the new power flow direction. The bidirectional (power) manager may assign the new operating characteristics by switching a flag bit (e.g., TMN_SIDE discussed in more detail below) to indicate operation as a transmitter / inverter or operation as a receiver / rectifier.

[0143] In response to the new operating characteristic assignment, the various major device controllers may reconfigure their respective operations. For example, the controllers may load control algorithms (e.g., software code blocks) to perform operations according to the new power flow direction. For example, the TMN controller may reset the TMN and load control code to generate appropriate TMN control signals to operate according to the new power flow direction. The TMN may need to adjust set points (e.g., impedance values ​​and / or protection schemes) to accommodate power transfer in the new direction or to prepare for power ramp-up in the new direction, or both.

[0144] The primary device (e.g., an inverter controller of the primary device) may control the inverter-rectifier operation according to the new operating characteristics (822). For example, the inverter-rectifier controller may load an appropriate algorithm to generate PWM control signals to operate as an inverter when the auxiliary device is a transmitter and to operate as a rectifier when the auxiliary device is a receiver. In some embodiments, a TMN controller in the primary device may control the TMN according to the new operating characteristics. For example, the TMN controller on the primary device may load an appropriate control algorithm to generate TMN adjustment signals to operate as a load-coupled TMN in a first direction or as a source-coupled TMN in a second direction.

[0145] Fig. 9 1 is a schematic diagram 900 of an exemplary inverter-rectifier 902 and a timing diagram 902 illustrating the operation of the inverter-rectifier in the inverter operating mode. Schematic diagram 1800 shows a phase-shifted full-bridge inverter. The inverter bridge circuit uses active switching elements Q1, Q2, Q3 and Q4, which can be, for example, MOSFETs, transistors, FETs, IGBTs, etc.

[0146] Timing diagram 902 illustrates the drive signal pattern for switches Q1, Q2, Q3, and Q4. The switches are grouped into two legs: Leg A (Q1, Q3) and Leg B (Q2, Q4). The corresponding switch in each leg is alternately turned on and off by a corresponding PWM control signal. The on time and off time of each gate drive signal G1, G2, G3, and G4 are shown. The dead time td shown is when the gate drivers of the same leg are all off. For each drive signal in period Ts, the off time can be greater than the on time.

[0147] The delay time tps between leg A (Q1 and Q3) and leg B (Q2 and Q4) is called the phase shift angle when expressed in degrees, and is a means for adjusting the total power provided by the inverter-rectifier when operating as an inverter. At startup, the output power VAB(t) from the inverter-rectifier terminals VA and VB can have an 11% duty cycle (leg phase shift angle θps = 20 degrees). At maximum power, VAB(t) can be at 100% duty cycle (leg phase θps = 180 degrees). The total power output is controlled by adjusting the delay time tPS between the leg A and leg B PWM signals.

[0148] In some embodiments, the inverter-rectifier 900 can operate according to one or more active rectification methods described herein (e.g., methods 304, 402, 502, and / or 602). Although a full-bridge inverter is shown, in some embodiments, the inverter-rectifier switches can be arranged in a half-bridge configuration. In some embodiments, the inverter-rectifier can implement zero voltage switching operation to ensure that the switch operates when the voltage across it is zero or close to zero.

[0149] Fig.10 is a schematic diagram 1000 of an exemplary inverter-rectifier and a timing diagram 1902 illustrating operation of the inverter-rectifier 702 in a rectifier operating mode. Fig.10 Instructions for using Fig. 9 1902. The gate drive signals (G1, G2, G3, G4) corresponding to the respective switches (Q1, Q2, Q3, Q4) are shown in timing diagram 1902. Although zero current switching operation is shown, zero voltage switching (ZVS) naturally follows operation and can be used in some embodiments. However, the ZVS switch in active rectification mode is not shown in the figure.

[0150] The synchronous rectifier can receive the I3s current (at Figure 7 13d or I3s), and generate the timing of synchronous rectification (zero current switch) as shown in timing diagram 1002. In rectifier mode, inverter-rectifier 702 rectifies the AC input signal into a DC output signal by alternately connecting the corresponding switch pairs (Q1 / Q4 and Q2 / Q3). For example, an inverter-rectifier controller (e.g., inverter / protection and control circuit system) can receive I3d or I3s current and / or phase measurement from a current or phase sensor (e.g., sensor 218). Switches Q1, Q2, Q3 and Q4 can be closed at zero current (or near zero current) of the input of inverter-rectifier 702, and allow a suitable time delay td to pass before operating the next pair of switches (e.g., Q1 and Q4 or Q2 and Q3). This can prevent power loss in the switch. In some embodiments, the time delay can be adjusted by the system as needed.

[0151] In some embodiments, during startup, the inverter-rectifier does not start switching until the measured input power is above a threshold value that ensures continuous conduction of the I3d current. The threshold value may be, for example, between 2kW and 4kW, and / or between 20% and 40% of the target power. During low-power operation below the threshold input power value, the input AC signal may be noisy, which may lead to inaccurate zero-crossing detection and possibly large transients for inaccurate switching. For example, the I3d current used to generate PWM synchronization may be discontinuous and noisy, resulting in inaccurate zero-crossing detection and possibly large transients, or even causing a destructive short circuit of the power stage. Alternatively, when the power is below the threshold, rectification can be performed passively by the body diode conduction of the switch. In such embodiments, the switching operation performed above the threshold input power value can be regarded as an active rectification mode, and the body diode conduction performed below the threshold input power value can be regarded as a passive rectification mode.

[0152] In some embodiments, inverter-rectifier 1000 may operate according to one or more active rectification methods described herein (eg, methods 304 , 402 , 502 , and / or 602 ).

[0153] Hardware and software implementation

[0154] In some instances, some or all of the processing described above may be performed on one or more central computing devices. In some instances, some types of processing occur on one device and other types of processing occur on another device. In some instances, some or all of the data described above may be stored in a data storage device hosted on one or more central computing devices, or stored via a cloud-based storage device. In some instances, some data is stored in one location and other data is stored in another location. In some instances, quantum computing may be used. In some instances, functional programming languages ​​may be used. In some instances, electrical storage such as flash-based memory may be used.

[0155] Fig.111100 is a block diagram of an example computer system 1100 that can be used in the process of implementing the techniques described herein. A general-purpose computer, a network appliance, a mobile device, or other electronic system may also include at least a portion of the system 1100. The system 1100 includes a processor 1110, a memory 1120, a storage device 1130, and an input / output device 1140. Each of the components 1110, 1120, 1130, and 1140 may be interconnected, for example, using a system bus 1150. The processor 1110 is capable of processing instructions for execution within the system 1100. In some embodiments, the processor 1110 is a single-threaded processor. In some embodiments, the processor 1110 is a multi-threaded processor. The processor 1110 is capable of processing instructions stored in the memory 1120 or on the storage device 1130.

[0156] Memory 1120 stores information within system 1100. In some implementations, memory 1120 is a non-transitory computer-readable medium. In some implementations, memory 1120 is a volatile memory unit. In some implementations, memory 1120 is a non-volatile memory unit.

[0157] The storage device 1130 is capable of providing mass storage for the system 1100. In some embodiments, the storage device 1130 is a non-temporary computer-readable medium. In various embodiments, the storage device 1130 may include, for example, a hard disk device, an optical disk device, 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.). The input / output device 1140 provides input / output operations for the system 1100. In some embodiments, the input / output device 1140 may include one or more of 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 modem). In some embodiments, the 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, a printer, and a display device 1160. In some examples, mobile computing devices, mobile communication devices, and other devices may be used.

[0158] In some embodiments, at least a portion of the methods described above may be implemented by instructions that, when executed, cause one or more processing devices to perform the processes and functions described above. These instructions may include, for example, interpreted instructions such as script instructions or executable code or other instructions stored in a non-transitory computer-readable medium. Storage device 1130 may be implemented in a distributed manner over a network such as a server cluster or a group of widely distributed servers, or may be implemented in a single computing device.

[0159] although Fig.11 An example processing system has been described in the specification, but embodiments of the subject matter, functional operations, and processes described in this specification 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 in this specification and their structural equivalents, or in a combination of one or more of them. Embodiments of the subject matter described in this specification may be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a tangible, non-volatile program carrier for execution by a data processing apparatus, or to control the operation of a data processing apparatus. Alternatively or in addition, the program instructions may be encoded on an artificially generated propagated signal, such as a machine-generated electrical, optical, or electromagnetic signal generated to encode information for transmission to a suitable receiver apparatus for execution by a 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 of them.

[0160] The term "system" may encompass all kinds of equipment, devices and machines for processing data, including (by way of example) a programmable processor, a computer or multiple processors or computers. A processing system may include special-purpose logic circuitry, such as an 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 an execution environment for the computer program in question, such as code constituting processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them.

[0161] A computer program (which may also be referred to or described as a program, software, software application, module, software module, script, or code) may be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and may be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program may be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files storing portions of one or more modules, subroutines, or code). A computer program may be deployed to execute on one computer or on multiple computers located at one site or distributed across multiple sites and interconnected by a communication network.

[0162] The processes or logic flows described in this specification may be performed by one or more programmable computers executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by, and the apparatus may be implemented as, special purpose logic circuits, such as FPGAs (field programmable gate arrays) or ASICs (application specific integrated circuits).

[0163] A computer suitable for executing a computer program may include, by way of example, a general or special purpose microprocessor, or both, or any other type of central processing unit. Typically, the central processing unit will receive instructions and data from a read-only memory or a random access memory, or both. A computer typically includes a central processing unit for executing or running instructions, and one or more memory devices for storing instructions and data. In general, a computer will also include or be operatively coupled to receive data from or transfer data to or both of one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks. However, a computer need not have such devices.

[0164] Computer-readable media suitable for storing computer program instructions and data include all forms of nonvolatile memory, media, and storage devices, including, by way of example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[0165] Embodiments of the subject matter described in this specification may be implemented in a computing system that includes a back-end component, such as a data server, or includes a middleware component, such as an application server, or includes a front-end component, such as a client computer with a graphical user interface or a web browser through which a user can interact with the embodiments of the subject matter described in this specification, or any combination of one or more of these back-end, middleware, or front-end components. The components of the system may be interconnected by digital data communication (e.g., a communication network) in any form or medium. Examples of communication networks include local area networks ("LANs") and wide area networks ("WANs"), such as the Internet.

[0166] A computing system may include clients and servers. Clients and servers are generally remote from each other and typically interact through a communication network. The client-server relationship arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

[0167] Although this specification contains many specific implementation details, these should not be interpreted as limitations on the scope of protection that can be claimed, but rather as descriptions of features that can be specific to a particular embodiment. Certain features described in the context of a separate embodiment in this specification may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented in multiple embodiments separately or in the form of any suitable sub-combination. In addition, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features of the claimed combination may be removed from the combination in some cases, and the claimed combination may be directed to a sub-combination or a variant of the sub-combination.

[0168] Similarly, although operations are depicted in a particular order in the drawings, this should not be understood as requiring that such operations be performed in the particular order shown or in a sequential order, or that all illustrated operations be performed, to achieve the desired results. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of various system components in the above-described embodiments should not be understood as requiring such separation in all embodiments, but it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0169] Specific embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. For example, the actions described in the claims can be performed in a different order and still achieve desirable results. As an example, the processes depicted in the accompanying drawings do not necessarily require the particular order or sequential order shown to achieve desirable results. In certain embodiments, multitasking and parallel processing may be advantageous. Other steps or stages may be provided, or steps or stages may be removed from the described processes. Therefore, other embodiments are within the scope of the following claims.

[0170] the term

[0171] The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0172] The term "substantially", the phrase "substantially equal to" and other similar phrases (e.g., "X has a value of approximately Y" or "X is approximately equal to Y") as 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 indicated, the predetermined range may be plus or minus 20%, 10%, 5%, 3%, 1%, 0.1%, or less than 0.1%.

[0173] The indefinite article "one" as used in the specification and claims shall be understood to mean "at least one" unless explicitly indicated to the contrary. The phrase "and / or" as used in the specification and claims shall be understood to mean "either one or both" of the elements so combined, that is, the elements are present in combination in some cases and separately in other cases. Multiple elements listed with "and / or" should be interpreted in the same way, that is, "one or more" of the elements are so combined. In addition to the elements specifically identified by the "and / or" clause, other elements may optionally be present, whether related or unrelated to those specifically identified. Therefore, as a non-limiting example, a reference to "A and / or B" when used in conjunction with an open language such as "including" may refer to only A (optionally including elements other than B) in one embodiment; in another embodiment, only B (optionally including elements other than A); in yet another embodiment, A and B (optionally including other elements), etc.

[0174] As used in this specification and claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when multiple items are separated in a list, "or" or "and / or" will be interpreted as inclusive, that is, including at least one, but also including more than one and optionally additional unlisted items in multiple elements or lists of elements. Only terms that clearly indicate the opposite, such as "only one of..." or "just one of..." or "consisting of..." when used in the claims will refer to the inclusion of just one element in several elements or lists of elements. In general, when preceded by exclusive terms, such as "any one", "one of...", "only one of...", or "exact one of...", the term "or" used should only be interpreted as indicating exclusive alternative forms (e.g., "one or the other, but not both"). "Substantially consisting of..." when used in the claims should have its ordinary meaning as used in the field of patent law.

[0175] As used in this specification and claims, the phrase "at least one" 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 of elements, but does not necessarily include at least one of each element specifically listed in the list of elements, and does not exclude any combination of elements in the list of elements. This definition also allows that elements other than the elements specifically identified in the list of elements to which the phrase "at least one" refers may optionally be present, whether or not related to those elements specifically identified. 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, without B (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one B, without A (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one A, and at least one B, optionally including more than one B (and optionally including other elements), etc.

[0176] The use of "including," "comprising," "having," "containing," "involving," and variations thereof, is meant to encompass the items listed thereafter as well as additional items.

[0177] The use of ordinal terms such as "first," "second," "third," etc., to modify claim elements in the claims does not by itself imply any priority, precedence, or order of one claim element relative to another claim element, or a temporal order of the acts of performing a method. Ordinal terms are used only as labels to distinguish one claim element having a particular name from another element having the same name (but for the purpose of use of the ordinal terms) to distinguish claim elements.

Claims

1. A method for operating an inverter-rectifier of a bidirectional wireless power system, the method comprising: determining a power flow direction of the bidirectional wireless power system; in response to a determination that the power flow direction is a first power flow direction, controlling the inverter-rectifier to operate in a rectifier mode; generating a zero-crossing signal representing one or more zero-crossings of a current at an input of the inverter-rectifier during the rectifier mode, wherein a rising edge of the zero-crossing signal indicates a zero-crossing corresponding to a rise in the current and a falling edge of the zero-crossing signal indicates a zero-crossing corresponding to a fall in the current; determining a first delay time based on at least one bidirectional wireless power system parameter and the zero-crossing signal during the rectifier mode; During the rectifier mode, generating a first control signal and a second control signal for a first switch and a second switch of the inverter-rectifier based on the first delay time and the rising edge and the falling edge of the zero-crossing signal, respectively; inserting a first dead time between the first control signal and the second control signal during the rectifier mode; as well as During the rectifier mode, the first control signal and the second control signal are provided to the first switch and the second switch, respectively.

2. The method according to claim 1, further comprising: determining a second delay time during the rectifier mode based on the bidirectional wireless power system parameters and the zero-crossing signal; During the rectifier mode, generating a third control signal and a fourth control signal for a third switch and a fourth switch of the inverter-rectifier based on the second delay time and the rising edge and the falling edge of the zero-crossing signal, respectively; inserting a second dead time between the third control signal and the fourth control signal during the rectifier mode; and During the rectifier mode, the third control signal and the fourth control signal are provided to the third switch and the fourth switch, respectively.

3. The method according to claim 2, wherein: The third switch and the fourth switch are coupled to the first switch and the second switch in a full-bridge configuration.

4. The method according to claim 1, wherein: The first switch and the second switch are operated to provide DC power to a voltage bus of the bidirectional wireless power system during the rectifier mode, the voltage bus being configured to provide the received DC power to one of a power source or a load.

5. The method according to claim 1, further comprising: In response to a determination that the power flow direction is a second power flow direction, the inverter-rectifier is controlled to operate in an inverter mode.

6. The method according to claim 5, wherein: The first switch and the second switch are operated to provide AC power to a resonator coil of the bidirectional wireless power system during the inverter mode.

7. The method according to claim 1, wherein: Determining a power flow direction of the two-way wireless power system includes receiving an indication of the power flow direction from a controller of the two-way wireless power system.

8. The method according to claim 1, wherein: Determining a power flow direction of the two-way wireless power system includes receiving an indication of the power flow direction from a wireless power receiver of the two-way wireless power system.

9. An inverter-rectifier for a bidirectional wireless power system, the inverter-rectifier comprising: a first switch and a second switch coupled to a resonator coil of the bidirectional wireless power system; as well as a control system coupled to each of the first switch and the second switch, the control system being configured to: determining a power flow direction of the bidirectional wireless power system; in response to a determination that the power flow direction is a first power flow direction, controlling the inverter-rectifier to operate in a rectifier mode; generating a zero-crossing signal representing one or more zero-crossings of a current at an input of the inverter-rectifier during the rectifier mode, wherein a rising edge of the zero-crossing signal indicates a zero-crossing corresponding to a rise in the current and a falling edge of the zero-crossing signal indicates a zero-crossing corresponding to a fall in the current; determining a first delay time based on at least one bidirectional wireless power system parameter and the zero-crossing signal during the rectifier mode; During the rectifier mode, generating a first control signal and a second control signal for a first switch and a second switch of the inverter-rectifier, respectively, based on the first delay time and the rising edge and the falling edge of the zero-crossing signal; inserting a first dead time between the first control signal and the second control signal during the rectifier mode; as well as During the rectifier mode, the first control signal and the second control signal are provided to the first switch and the second switch, respectively.

10. The inverter-rectifier according to claim 9, wherein: The control system is also configured to: determining a second delay time during the rectifier mode based on the bidirectional wireless power system parameters and the zero-crossing signal; During the rectifier mode, generating a third control signal and a fourth control signal for a third switch and a fourth switch of the inverter-rectifier based on the second delay time and the rising edge and the falling edge of the zero-crossing signal, respectively; inserting a second dead time between the third control signal and the fourth control signal during the rectifier mode; and During the rectifier mode, the third control signal and the fourth control signal are provided to the third switch and the fourth switch, respectively.

11. The inverter-rectifier according to claim 10, wherein: The third switch and the fourth switch are coupled to the first switch and the second switch in a full-bridge configuration.

12. The inverter-rectifier according to claim 9, wherein: The first switch and the second switch are operated to provide DC power to a voltage bus of the bidirectional wireless power system during the rectifier mode, the voltage bus being configured to provide the received DC power to one of a power source or a load.

13. The inverter-rectifier according to claim 9, further comprising: In response to a determination that the power flow direction is a second power flow direction, the inverter-rectifier is controlled to operate in an inverter mode.

14. The inverter-rectifier according to claim 13, wherein: The first switch and the second switch are operated to provide AC power to the resonator coil during the inverter mode.

15. The inverter-rectifier according to claim 9, wherein: Determining a power flow direction of the bidirectional wireless power system includes receiving an indication of the power flow direction from a controller external to the control system of the inverter-rectifier.

16. The inverter-rectifier according to claim 9, wherein: Determining a power flow direction of the two-way wireless power system includes receiving an indication of the power flow direction from a wireless power receiver of the two-way wireless power system.

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