Wireless power transmission device and control method

Abstract

The present application provides a wireless power transmission device and a control method. The wireless power transmission device includes a transmitting unit including an inverter circuit, a first compensation circuit and a transmitting coil; the receiving unit includes a receiving coil, a second compensation circuit and a rectifier circuit. The power adjustment unit is used to adjust the output signal of the wireless power transmission device. The control unit is used to obtain the voltage and current phase difference, the detection signal and the power detection value of the wireless power transmission device of the transmitting unit; control the operating frequency of the inverter circuit according to the voltage and current phase difference and the preset phase difference, so that the voltage and current phase difference is equal to the predetermined phase difference, and generate a power derating signal according to the detection signal, and control the power adjustment unit to adjust the output signal according to the power derating signal, the power detection value and the power given signal. The present application reduces the current or voltage of the transmitting unit by reducing the output signal of the device, thereby improving the efficiency of wireless power transmission, thereby reducing the heating of the device and ensuring the continuous operation of the device.

Description

Technical Field

[0001] The present application relates to the technical field of wireless power transmission, and in particular to a wireless power transmission device and a control method. Background Art

[0002] Currently, the most common wireless power transmission technology is electromagnetic induction technology, which uses magnetic fields to transmit energy between power supply devices and power consumption devices without the need for wires to connect the two.

[0003] A common wireless power transmission device includes a transmitting unit and a receiving unit. The transmitting unit includes a transmitting coil and an inverter circuit, and the receiving unit includes a receiving coil and a rectifier circuit. Among them, the transmitting coil and the receiving coil constitute a loosely coupled transformer. The coupling coefficient of the loosely coupled transformer is low, resulting in a large reactive power circulation, which in turn increases its loss. In particular, when the distance between the transmitting coil and the receiving coil increases or there is an offset between the transmitting coil and the receiving coil, the loss of the loosely coupled transformer further increases, the transmission efficiency of the wireless power transmission device is significantly reduced, and the thermal stress increases. The load of the wireless power transmission device is an energy storage device, such as a battery, etc. This energy storage device is different from a conventional electrical load and often allows the wireless power transmission device to reduce the output power under non-rated operating conditions (such as non-rated operating temperature) to reduce thermal stress.

[0004] In order to improve the transmission efficiency and thermal stress problem of the wireless power transmission device, a compensation method is often used to couple a compensation circuit between the transmitting coil and the inverter circuit, and to couple a compensation circuit between the receiving coil and the rectifier circuit to reduce the reactive power during power transmission, thereby reducing the loss of the loosely coupled transformer. However, it is difficult to reduce the current of the transmitting unit by reducing the output power using the compensation method, so that the wireless power transmission device has a thermal stress problem when it works beyond the rated operating temperature range, thereby causing damage to the wireless power transmission device or triggering the over-temperature protection to stop the wireless power transmission device from operating.

[0005] Therefore, how to develop a wireless power transmission device that can overcome the above-mentioned defects is currently an urgent need. Summary of the invention

[0006] The present application provides a wireless power transmission device and a control method, aiming to provide a wireless power transmission device capable of reducing the voltage or current of a transmitting unit by reducing an output signal.

[0007] In a first aspect, the present application provides a wireless power transmission device, comprising:

[0008] The transmitting unit comprises an inverter circuit, a first compensation circuit and a transmitting coil; the first compensation circuit is coupled between the inverter circuit and the transmitting coil;

[0009] The receiving unit comprises a receiving coil, a second compensation circuit and a rectifier circuit; the second compensation circuit is coupled between the receiving coil and the rectifier circuit;

[0010] a power regulating unit, used for regulating the output signal of the wireless power transmission device; and

[0011] A control unit is coupled to the inverter circuit and the power regulating unit respectively, and is used to obtain the voltage and current phase difference of the transmitting unit, the detection signal and the power detection value of the wireless power transmission device; control the operating frequency of the inverter circuit according to the voltage and current phase difference and the preset phase difference, so that the voltage and current phase difference is equal to the preset phase difference, and generate a power derating signal according to the detection signal, and control the power regulating unit to adjust the output signal according to the power derating signal, the power detection value and the power given signal.

[0012] Optionally, the first compensation circuit, the transmitting coil, the receiving coil and the second compensation circuit form a resonant network;

[0013] The resonant network includes a first resonant frequency point and a second resonant frequency point, wherein the second resonant frequency point is greater than the first resonant frequency point;

[0014] The operating frequency is greater than the second resonant frequency point, the operating frequency is equal to the second resonant frequency point, or the operating frequency is less than the second resonant frequency point and greater than the first resonant frequency point.

[0015] Optionally, the wireless power transmission device further includes: a phase detection unit;

[0016] The phase detection unit is coupled to the transmitting unit and the control unit, and is used for acquiring the voltage phase signal and the current phase signal of the transmitting unit, and calculating the voltage-current phase difference according to the voltage phase signal and the current phase signal.

[0017] Optionally, the phase detection unit includes: a voltage phase detection unit, a current phase detection unit and a phase difference calculation unit;

[0018] The voltage phase detection unit is coupled to the output end of the inverter circuit and is used to detect the voltage phase signal of the transmitting unit;

[0019] The current phase detection unit is coupled between the inverter circuit and the first compensation circuit, or between the first compensation circuit and the transmitting coil, and is used to detect the current phase signal of the transmitting unit;

[0020] The phase difference calculation unit is used to obtain a voltage phase signal and a current phase signal, and calculate a voltage-current phase difference according to the voltage phase signal and the current phase signal.

[0021] Optionally, the control unit is specifically used for:

[0022] When the detection signal reaches a preset value, a power derating signal is generated, a power adjustment signal is provided according to the power derating signal and the power given signal, and the power adjustment unit is controlled to reduce the output signal according to the power adjustment signal and the power detection value, thereby reducing the current of the transmitting unit or reducing the voltage of the transmitting unit.

[0023] Optionally, the detection signal is a temperature signal, and the preset value is a preset temperature value;

[0024] The control unit is used to generate a power derating signal when the temperature signal reaches a preset temperature value.

[0025] Optionally, the detection signal is a duration signal, and the preset value is a preset duration signal;

[0026] The control unit is used for generating a power reduction signal when the duration signal reaches a preset duration signal.

[0027] Optionally, it also includes: a temperature detection unit;

[0028] The temperature detection unit is coupled to the control unit, and is used to detect the ambient temperature or the temperature of the components of the wireless power transmission device, and provide a temperature signal.

[0029] Optionally, it also includes: an output power detection unit;

[0030] The output power detection unit is coupled to the output end of the wireless power transmission device and the control unit, and is used for detecting the output power of the wireless power transmission device and providing a power detection value.

[0031] Optionally, it further includes: an output current detection unit and an output voltage detection unit;

[0032] The output current detection unit is coupled to the output end of the wireless power transmission device and the control unit, and is used to detect the output current of the wireless power transmission device and provide a current detection value;

[0033] The output voltage detection unit is coupled to the output terminal of the wireless power transmission device and the control unit, and is used to detect the output voltage of the wireless power transmission device and provide a voltage detection value;

[0034] The control unit is used to obtain a current detection value and a voltage detection value, and obtain a power detection value according to the current detection value and the voltage detection value.

[0035] Optionally, the output signal includes one or more of output current, output voltage, or output power.

[0036] Optionally, the power regulation unit includes any one of a buck circuit, a boost circuit, or a buck-boost circuit.

[0037] Optionally, the power regulating unit is electrically coupled between the input terminal of the wireless power transmission device and the transmitting unit; or,

[0038] The power regulating unit is electrically coupled between the receiving unit and the output end of the wireless power transmission device.

[0039] Optionally, the transmitting unit further includes a transmitting end transformer;

[0040] The transmitter transformer is coupled between the inverter circuit and the first compensation circuit; or,

[0041] The transmitting-end transformer is coupled between the first compensation circuit and the transmitting coil.

[0042] Optionally, the receiving unit further includes: a receiving-end transformer;

[0043] The receiving-end transformer is coupled between the receiving coil and the second compensation circuit; or,

[0044] The receiving-end transformer is coupled between the second compensation circuit and the rectifying circuit.

[0045] In a second aspect, the present application provides a control method for a wireless power transmission device, the method being applied to the wireless power transmission device involved in the first aspect and the optional solution; the method comprising:

[0046] Get the detection signal;

[0047] Obtaining the voltage and current phase difference of the transmitting unit;

[0048] Get the power detection value;

[0049] The operating frequency of the inverter circuit is controlled according to the voltage-current phase difference and the preset phase difference, so that the voltage-current phase difference is equal to the preset phase difference, a power derating signal is generated according to the detection signal, and the power regulating unit is controlled to adjust the output signal of the wireless power transmission device according to the power derating signal, the power detection value and the power given signal.

[0050] Optionally, obtaining a voltage and current phase difference signal of the transmitting unit specifically includes:

[0051] Acquire a voltage phase signal of a transmitting unit;

[0052] Acquire the current phase signal of the transmitting unit;

[0053] The voltage and current phase difference is calculated based on the voltage phase signal and the current phase signal.

[0054] Optionally, generating a power reduction signal according to the detection signal, and controlling a power adjustment unit to adjust an output signal of the wireless power transmission device according to the power reduction signal, the power detection value and the power given signal, specifically includes:

[0055] When the detection signal reaches a preset value, a power derating signal is generated, a power adjustment signal is provided according to the power derating signal and the power given signal, and the power adjustment unit is controlled to reduce the output signal according to the power adjustment signal and the power detection value, thereby reducing the current of the transmitting unit or reducing the voltage of the transmitting unit.

[0056] Optionally, the detection signal is a temperature signal, and the preset value is a preset temperature value;

[0057] When the temperature signal reaches a preset temperature value, a power derating signal is generated.

[0058] Optionally, obtaining a power detection value includes:

[0059] Get the current detection value;

[0060] Get the voltage detection value;

[0061] The power detection value is calculated based on the current detection value and the voltage detection value.

[0062] The present application provides a wireless power transmission device and a control method, which controls the operating frequency of an inverter circuit by means of a voltage-current phase difference and a predetermined phase difference so that the voltage-current phase difference of a transmitting unit is equal to the predetermined phase difference, and controls a power adjustment unit to adjust an output signal by means of a detection signal, a power detection value and a power given signal, so that the wireless power transmission device operates under a condition of reducing the output power, thereby reducing the voltage or current of the transmitting unit, reducing the heat generation of the wireless power transmission device, and ensuring the continuous operation of the wireless power transmission device. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 A schematic diagram of a circuit structure of a wireless power transmission device provided by an embodiment;

[0064] Figure 2 for Figure 1 A schematic diagram of a compensation fundamental wave equivalent circuit of the wireless power transmission device shown;

[0065] Figure 3 A schematic diagram of the circuit structure of another wireless power transmission device provided by an embodiment;

[0066] Figure 4 for Figure 3 A schematic diagram of a compensation fundamental wave equivalent circuit of the wireless power transmission device shown;

[0067] Figure 5 A schematic diagram of a circuit structure of another wireless power transmission device provided in an embodiment of the present application;

[0068] Figure 6 A schematic diagram of the relationship between phase and frequency provided in an embodiment of the present application;

[0069] Figure 7 A schematic diagram of a wireless power transmission device provided by another embodiment of the present application;

[0070] Figure 8 A schematic diagram of a phase detection unit provided in an embodiment of the present application;

[0071] Fig. 9 A schematic diagram of the circuit structure of a wireless power transmission device provided in another embodiment of the present application;

[0072] Fig.10 A schematic diagram of the effect of a wireless power transmission device provided by another embodiment of the present application;

[0073] Fig.11 A schematic diagram of the effect of a wireless power transmission device provided by another embodiment of the present application;

[0074] Fig.12 A schematic diagram of the circuit structure of a wireless power transmission device provided in another embodiment of the present application;

[0075] Fig.13 A schematic diagram of the circuit structure of a wireless power transmission device provided in another embodiment of the present application;

[0076] Fig.14 A schematic diagram of the circuit structure of a wireless power transmission device provided in another embodiment of the present application;

[0077] Fig.15 A schematic diagram of the circuit structure of a wireless power transmission device provided in another embodiment of the present application;

[0078] Fig.16 A schematic diagram of the circuit structure of a wireless power transmission device provided in another embodiment of the present application;

[0079] Fig.17 A schematic diagram of the circuit structure of a wireless power transmission device provided in another embodiment of the present application;

[0080] Fig.18 A schematic diagram of the circuit structure of a wireless power transmission device provided in another embodiment of the present application;

[0081] Fig.19 A schematic flow chart of a control method for a wireless power transmission device provided in another embodiment of the present application. DETAILED DESCRIPTION

[0082] In order to make the purpose, technical solution and advantages of this application clearer, the technical solution in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0083] like Figure 1 As shown, the wireless power transmission device includes a transmitting unit 1 and a receiving unit 2, wherein the transmitting unit 1 includes an inverter circuit 11, a first compensation circuit 12 and a transmitting coil L p The first compensation circuit 12 is coupled to the inverter circuit 11 and the transmitting coil L p The receiving unit 2 includes a receiving coil L s , a second compensation circuit 22 and a rectifier circuit 23, wherein the second compensation circuit 22 is coupled to the receiving coil L s and the rectifier circuit 23. In this embodiment, the first compensation circuit 12 and the second compensation circuit 22 are both series compensation circuits. Specifically, the first compensation circuit 12 includes a capacitor C1, and the second compensation circuit includes a capacitor C2. The capacitor C1 is coupled in series to the inverter circuit 11 and the transmitting coil L. p The capacitor C2 is connected in series to the receiving coil L s and the rectifier circuit 23. By adopting the fundamental wave equivalent, the following can be obtained: Figure 2 The compensation fundamental wave equivalent circuit is shown. When the wireless power transmission device works on the compensation transmitting coil L p At the resonant frequency of the self-inductance, the capacitor C1 completely compensates for the self-inductance, and the current I1 of the transmitting unit 1 can be calculated as:

[0084]

[0085] Wherein, U2 represents the voltage value of the output voltage of the wireless power transmission device, ω represents the current angular frequency of the transmitting unit 1, and M represents the transmitting coil L p and receiving coil L s The value of the mutual inductance between them.

[0086] Figure 3 and Figure 1 Most of the circuit structures in the wireless power transmission devices shown are the same, and the same circuit structures will not be repeated here. Figure 3 and Figure 1 The first compensation circuit and the second compensation circuit in the wireless power transmission device shown in FIG. Figure 3As shown, the first compensation circuit 32 and the second compensation circuit 42 in the wireless power transmission device are both inductor capacitor capacitor (LCC) compensation circuits. Specifically, the first compensation circuit 32 includes an inductor L1, a capacitor C p1 and capacitor C s1 , one end of the inductor L1 and the capacitor C p1 One end and capacitor C s1 The other end of the inductor L1 is coupled to an output end of the inverter circuit 31, and the capacitor C p1 The other end is electrically coupled to the other output end of the inverter circuit 31 and the transmitting coil L p One end of the capacitor C s1 The other end is electrically coupled to the transmitting coil L p The other end; the second compensation circuit 42 includes an inductor L2, a capacitor C p2 and capacitor C s2 , one end of the inductor L2 and the capacitor C p2 One end and capacitor C s2 The other end of the inductor L2 is coupled to an input end of the rectifier circuit 33, and the capacitor C p2 The other end is electrically coupled to the receiving coil L s and the other input end of the rectifier circuit 43, the capacitor C s2 The other end is electrically coupled to the receiving coil L s The other end of the baseband. After using the fundamental wave equivalent, we can get Figure 4 The compensation fundamental wave equivalent circuit shown in FIG. 1 shows that when the working point of the wireless power transmission device satisfies the following equations (2) to (5), the current I1 of the transmitting unit 1 can be calculated as follows:

[0087]

[0088]

[0089]

[0090]

[0091]

[0092] Where, L1 represents the inductance value of the compensation inductor, C p1 Indicates the capacitance value of the compensation capacitor, C s1 represents the capacitance value of the compensation capacitor, L2 represents the inductance value of the compensation inductor, C p2 Indicates the capacitance value of the compensation capacitor, C s2 represents the capacitance value of the compensation capacitor, ω represents the current angular frequency of the transmitting unit 1, and M is the transmitting coil Lp and receiving coil L s U1 represents the inductance value of the mutual inductance between them, and U2 represents the voltage value of the input voltage of the rectifier circuit.

[0093] According to formulas (1) and (6), when the output power of the wireless power transmission device decreases, the current of the transmitting unit does not decrease accordingly, that is, the purpose of reducing the current of the transmitting unit by reducing the output power cannot be achieved. It should be noted that the current of the transmitting unit can be the output current of the inverter circuit.

[0094] To improve Figure 1 and Figure 3 The transmission efficiency and thermal stress issues of the wireless power transmission device shown, Figure 5 The provided wireless power transmission device can realize that the current or voltage of the transmitting unit decreases as the output power decreases.

[0095] like Figure 5 As shown, a wireless power transmission device provided in an embodiment of the present application includes a transmitting unit 10 , a receiving unit 20 , a power regulating unit 30 and a control unit 40 .

[0096] The transmitting unit 10 is used to receive electric energy Vin, where the electric energy can be direct current electric energy. The receiving unit 20 is used to connect to a load 90, where the load can be an energy storage device, such as a battery. The transmitting unit 10 also includes an inverter circuit 101, a first compensation circuit 102 and a transmitting coil 103. The first compensation circuit 102 is coupled between the inverter circuit 101 and the transmitting coil 103. Specifically, the first compensation circuit 102 can be connected in series with the transmitting coil 103 and then connected to the output end of the inverter circuit 101, or the first compensation circuit 102 can also be connected in parallel with the transmitting coil 103 and then connected to the output end of the inverter circuit 101.

[0097] The receiving unit 20 further includes a receiving coil 201, a second compensation circuit 202 and a rectifier circuit 203. The second compensation circuit 202 is coupled between the receiving coil 201 and the rectifier circuit 203. Specifically, the second compensation circuit 202 can be connected in series with the receiving coil 201 and then connected to the input end of the rectifier circuit 203, or the second compensation circuit 202 can be connected in parallel with the receiving coil 201 and then connected to the input end of the rectifier circuit 203.

[0098] in, Figure 5 The transmitting unit 10 and the receiving unit 20 in the Figure 1 The structures of the transmitting unit 1 and the receiving unit 2 may be the same; or Figure 5 The transmitting unit 10 and the receiving unit 20 in the Figure 3 The structures of the transmitting unit 3 and the receiving unit 4 can be the same.

[0099] The inverter circuit 101 may be a half-bridge inverter circuit or a full-bridge inverter circuit. The inverter circuit 101 is used to receive direct current power Vin and convert the direct current power into alternating current power. The first compensation circuit 102 is used to compensate for part of the reactive power of the transmitting coil 103, and the transmitting coil 103 is used to receive the alternating current power output by the inverter circuit 101 and generate an alternating magnetic field.

[0100] The receiving coil 201 is used to sense the alternating magnetic field and convert the alternating magnetic field into AC power. It should be noted that the AC power output by the inverter circuit 101 and the AC power received by the rectifier circuit can be the same or different. The second compensation circuit 202 is used to compensate for the reactive power of the receiving coil 201. The rectifier circuit 203 is used to receive AC power and convert the AC power into DC power. Among them, the rectifier circuit 203 can be a full-wave rectifier circuit or a full-bridge rectifier circuit.

[0101] The power regulating unit 30 is used to regulate the output signal of the wireless power transmission device, wherein the power regulating unit 30 can be any one of a buck circuit, a boost circuit or a buck-boost circuit. In the present embodiment, the power regulating unit 30 is coupled between the rectifier circuit 203 and the output end of the wireless power transmission device, and the output end of the wireless power transmission device is connected to the load 90. The control unit 40 is used to obtain the voltage and current phase difference, the detection signal and the power detection value of the wireless power transmission device of the transmitting unit 10. The operating frequency of the inverter circuit 101 is controlled according to the voltage and current phase difference and the preset phase difference, so that the voltage and current phase difference is equal to the predetermined phase difference. That is, the control unit 40 is used to compare the voltage and current phase difference with the preset phase difference, and generate a control signal of the inverter circuit 101 according to the comparison result of the voltage and current phase difference and the preset phase difference, and the control signal is used to control the operating frequency of the inverter circuit 101 so that the voltage and current phase difference of the transmitting unit 10 is equal to the predetermined phase difference. In the present embodiment, the preset phase difference can be set by the control unit 40 internally, or can be provided by an external circuit.

[0102] The control unit 40 is also used to generate a power reduction signal according to the detection signal, and control the power adjustment unit 30 to adjust the output signal of the wireless power transmission device according to the power reduction signal, the power detection value and the power setting signal. Specifically, the control unit 40 receives the detection signal, and when the detection signal reaches a preset value, the control unit 40 generates a power reduction signal, that is, the power reduction signal is generated only when the detection signal meets the preset condition, wherein the preset value can be set by the control unit 40 internally, or provided by an external circuit. The control unit 40 then generates a power adjustment signal according to the power derating signal and the power given signal, wherein the power given signal is the output power signal of the wireless power transmission device under rated conditions, and the power given signal can be provided by an external circuit, such as a voltage command and a current command provided by a charging protocol, and the power given signal is calculated according to the voltage command and the current command, or the voltage command and the current command are provided by an external battery system, and the power given signal is calculated according to the voltage command and the current command; or it can be set internally by the control unit 40; and compare the power adjustment signal with the power detection value, and generate a control signal according to the comparison result to control the power adjustment unit 30 to adjust the output signal of the wireless power transmission device, wherein the output signal includes one or more of the output voltage, the output current, or the output power. The control unit 40 controls the power adjustment unit 30 to adjust the output signal of the wireless power transmission device, that is, the control unit 40 controls the power adjustment unit 30 to reduce the output voltage and / or the output current to achieve the purpose of reducing the output power.

[0103] In this embodiment, the current of the transmitting unit 10 decreases as the output signal decreases; or the voltage of the transmitting unit 10 decreases as the output signal decreases.

[0104] The wireless power transmission device described in the above embodiment can operate with reduced output power, thereby reducing the current or voltage in the transmitting unit 10, reducing losses, reducing the thermal stress of the wireless power transmission device, and ensuring continuous operation of the wireless power transmission device.

[0105] The detection signal may be a temperature signal, and the preset value may be a preset temperature value. The control unit 40 receives the temperature signal, and generates a power derating signal when the temperature signal reaches the preset temperature value, wherein the preset temperature value may be the rated operating temperature of the wireless power transmission device, or may be the temperature limit value of the internal components of the wireless power transmission device. The control unit 40 then generates a power adjustment signal according to the power derating signal and the power given signal, and then controls the power adjustment unit 30 to reduce the output signal of the wireless power transmission device, such as the output power, according to the power adjustment signal and the power detection value of the wireless power transmission device detected in real time. When the temperature detection signal reaches the preset value, the current of the transmitting unit 10 decreases as the output signal decreases, or the voltage of the transmitting unit 10 decreases as the output signal decreases, so that the heat generated by the wireless power transmission device under the working condition exceeding the preset temperature value is reduced, the heating rate is reduced, the thermal stress of the wireless power transmission device is reduced, and the continuous operation of the wireless power transmission device is ensured.

[0106] Among them, the detection signal can be a duration signal, and the preset value can be a preset duration signal. The control unit 40 is used to generate a power derating signal when the duration signal reaches the preset duration signal, wherein the preset duration signal is the rated working duration of the wireless power transmission device. The control unit 40 then generates a power adjustment signal based on the power derating signal and the power given signal, and then controls the power adjustment unit 30 to reduce the output power signal of the wireless power transmission device based on the power adjustment signal and the power detection value of the wireless power transmission device detected in real time. When the duration signal reaches the preset value, the current of the transmitting unit 10 decreases as the output signal decreases, or the voltage of the transmitting unit 10 decreases as the output signal decreases, so that the heat generation of the wireless power transmission device under the working condition exceeding the preset temperature value is reduced, and the heating rate is reduced, so that the wireless power transmission device can work normally under the condition exceeding the preset duration signal, reduce the thermal stress of the wireless power transmission device, and ensure the continuous operation of the wireless power transmission device.

[0107] refer to Figure 5 The wireless power transmission device provided in this embodiment includes a transmitting unit 10, a receiving unit 20, a power regulating unit 30 and a control unit 40.

[0108] The transmitting unit 10 further includes an inverter circuit 101, a first compensation circuit 102 and a transmitting coil 103. The first compensation circuit 102 is coupled between the inverter circuit 101 and the transmitting coil 102. The receiving unit 20 further includes a receiving coil 201, a second compensation circuit 202 and a rectifier circuit 203. The second compensation circuit 202 is coupled between the receiving coil 201 and the rectifier circuit 203.

[0109] The first compensation circuit 102, the transmitting coil 103, the receiving coil 201 and the second compensation circuit 202 form a resonant network. In this embodiment, the parameters of the resonant network are designed by a bifurcation frequency compensation method, so that the resonant network has a frequency bifurcation phenomenon.

[0110] The above-mentioned bifurcation phenomenon is a concept of nonlinear dynamic system. For the soft switching system, in short, it is a phenomenon that the resonant frequency point where the phase of its input impedance is zero appears non-unique due to the change of system parameters, where the phase of the input impedance is zero, that is, the input port of the inverter circuit 101 of the transmitting unit 10 is equivalent to pure resistance, that is, the input impedance of the inverter circuit 101 is pure resistance.

[0111] Combination Figure 5 and Figure 6 In this embodiment, when the input impedance phase is 0, the resonant network includes three resonant frequency points, namely the first resonant frequency point (natural resonant frequency point), the second resonant frequency point (high bifurcation frequency point) and the third resonant frequency point (low bifurcation frequency point), wherein the second resonant frequency point is greater than the first resonant frequency point and greater than the third resonant frequency point. The control unit 40 controls the operating frequency of the inverter circuit 101 to be near the second resonant frequency point, so that the voltage and current phase difference of the transmitting unit is equal to the preset phase difference. Specifically, the operating frequency can be greater than the second resonant frequency point, or the operating frequency is equal to the second resonant frequency point, or the operating frequency point can be less than the second resonant frequency point and greater than the first resonant frequency point, thereby achieving a smaller current or voltage of the transmitting unit 10. This embodiment can reduce the voltage or current of the transmitting unit 10 as the output signal decreases, thereby reducing the thermal stress of the transmitting unit 10.

[0112] When the resonant network operates near the high bifurcation resonant frequency point, that is, when the switching frequency of the inverter circuit 101 is near the high bifurcation resonant frequency point, the first compensation circuit 102 cannot completely compensate the self-inductance of the transmitting coil 103, so that it presents a certain impedance, but the input impedance of the inverter circuit 101 presents pure resistance, so that the current or voltage of the transmitting unit 10 decreases as the output signal of the wireless power transmission device decreases, thereby reducing the thermal stress of the wireless power transmission device.

[0113] Combine the following Figure 2 , Figure 5 and Figure 6 The bifurcation frequency compensation method of the resonant network is described. The first compensation circuit 102 is a capacitor C1, and the second compensation capacitor 202 is a capacitor C2.

[0114] The key to the parameter design of the bifurcation frequency compensation is that the capacitors C1 and C2 do not completely compensate the self-inductances L1 and L2 of the transmitting coil 103 and the receiving coil 201, but make the capacitors C1 and C2 and the self-inductances L1 and L2 of the transmitting coil 103 and the receiving coil 201 present a certain impedance, but the input port of the inverter circuit 101 is still equivalent to pure resistance, that is, the phase angle of the voltage and current of the transmitting unit 10 is 0, that is, the input impedance of the inverter circuit 101 is pure resistance, and the imaginary part of the input impedance satisfies the following formula:

[0115]

[0116] Among them, U1 represents the voltage value of the output voltage of the inverter circuit 101, I1 represents the current value of the current of the transmitting unit 10, that is, the output current of the inverter circuit 101, and Im represents the imaginary part.

[0117] To simplify the analysis, a resonant network with symmetry between the primary and secondary sides is used as an example, that is, the self-inductance L1 of the transmitting coil 103 and the self-inductance L2 of the receiving coil 201 are equal in value, and the capacitance C1 and the capacitance C2 are equal in value. Figure 2 It can be seen from the schematic diagram of the compensation fundamental wave equivalent circuit that the output voltage U1 of the inverter circuit 101 and the current I1 of the transmitting unit 10 satisfy the following formula:

[0118]

[0119] The impedance formed by the capacitor C1 and the self-inductance L1 of the transmitting coil 103 satisfies the following formula:

[0120]

[0121] The input voltage U2 of the rectifier circuit 203 and the current I2 of the receiving unit 20 satisfy the following formula:

[0122]

[0123]

[0124] According to formulas (7)-(11), the operating frequency at which the input impedance of the inverter circuit 101 is purely resistive satisfies the following formula:

[0125]

[0126] in, is the output voltage vector of the inverter circuit, is the current vector of the transmitting unit 10, Z1 is the impedance value of the equivalent series impedance of the capacitor C1 and the self-inductance L1, ω is the angular frequency of resonance, M represents the inductance value of the mutual inductance between the transmitting coil 103 and the receiving coil 201, C1 is the capacitance value of the capacitor, L1 is the inductance value of the self-inductance of the transmitting coil 103, is the input voltage vector of the rectifier circuit, is the output current vector of the receiving unit 20, R L is the equivalent load resistance value.

[0127] According to formula (12), by designing different distances between the transmitting coil 103 and the receiving coil 201 and different loads coupled to the rectifier circuit 203, when When , the resonant network can have three resonant frequency points, namely the third resonant frequency point (low bifurcation frequency point), the first resonant frequency point (natural resonant frequency point) and the second resonant frequency point (high bifurcation frequency point), wherein the second resonant frequency point is greater than the first resonant frequency point, and the first resonant frequency point is greater than the third resonant frequency point, such as Figure 6 As shown. The control unit 40 controls the operating frequency (i.e., switching frequency) of the inverter circuit 101 to be near the high bifurcation frequency point, that is, the operating frequency is greater than the second resonant frequency point, the operating frequency is equal to the second resonant frequency point, or the operating frequency is less than the second resonant frequency point and greater than the first resonant frequency point, so that the voltage and current phase difference is equal to the preset phase difference. At this time, the operating frequency of the inverter circuit 101 is near the high bifurcation frequency point, so that the capacitors C1 and C2 and the self-inductances L1 and L2 of the transmitting coil 103 and the receiving coil 201 present a certain impedance, rather than an equivalent short circuit, and the current I1 of the transmitting coil 103 satisfies the following formula:

[0128]

[0129] in, represents the input voltage vector of the rectifier circuit, represents the output current vector of the receiving unit 20, Z2 is the impedance value of the equivalent series impedance of the capacitor C2 and the self-inductance L2, and Z2 and The calculation formula is as follows:

[0130]

[0131]

[0132] When the output voltage of the wireless power transmission device is fixed, by reducing the output power, that is, increasing R L , reducing the output current can reduce the current I1 of the emission unit 10, thereby reducing the thermal stress of the emission unit 10.

[0133] In this embodiment, during the operation of the wireless power transmission device, the control unit 40 obtains the voltage-current phase difference of the transmitting unit 10, and controls the operating frequency of the inverter circuit 101 to be greater than the second resonant frequency point according to the voltage-current phase difference and the preset phase difference, or controls the operating frequency to be equal to the second resonant frequency point, or controls the operating frequency to be less than the second resonant frequency point and greater than the first resonant frequency point, so that the voltage-current phase difference is equal to the preset phase difference, thereby enabling the current or voltage of the transmitting coil 103 to decrease as the output signal of the wireless power transmission device decreases. The purpose of reducing the heat generated by the device is achieved by reducing the output signal of the wireless power transmission device.

[0134] The control unit 40 generates a power derating signal according to the detection signal, and controls the power regulating unit 30 to regulate the output signal of the wireless power transmission device according to the power derating signal, the power detection value and the power given signal, so that the wireless power transmission device reduces the output power operation, thereby reducing the current or voltage of the transmitting unit 10, reducing the loss, and improving the efficiency and thermal stress problem of the device.

[0135] like Figure 7 As shown, a wireless power transmission device provided in another embodiment of the present application includes a transmitting unit 10, a receiving unit 20, a power adjustment unit 30, a phase detection unit 60, an output power detection unit 70 and a control unit 40.

[0136] The transmitting unit 10 includes: an inverter circuit 101, a transmitter transformer 104, a first compensation circuit 102, and a transmitting coil 103. In this embodiment, the transmitter transformer 104 is coupled between the inverter circuit 101 and the first compensation circuit 102, and the first compensation circuit 102 is coupled to the transmitting coil 103. In other embodiments, the first compensation circuit 102 is coupled between the inverter circuit 101 and the transmitter transformer 104, and the transmitter transformer 104 is coupled to the transmitting coil 103.

[0137] The receiving unit 20 includes: a receiving coil 201, a second compensation circuit 202, a receiving-end transformer 204, and a rectifier circuit 203. In this embodiment, the second compensation circuit 202 is coupled between the receiving coil 201 and the receiving-end transformer 204, and the receiving-end transformer 204 is coupled to the rectifier circuit 203. In other embodiments, the receiving-end transformer 204 is coupled between the receiving coil 201 and the second compensation circuit 202, and the second compensation circuit 202 is coupled to the rectifier circuit 203. The rectifier circuit 203 is coupled to the load 90.

[0138] It should be noted that the transmitting unit 10 may include a transmitting end transformer 104, while the receiving unit 20 may not include a receiving end transformer 204; or, the transmitting unit 10 may not include a transmitting end transformer 104, while the receiving unit 20 may include a receiving end transformer 204. Adding a transmitting end transformer 104 to the transmitting unit 10 or adding a receiving end transformer to the receiving unit 20 depends on the needs. As for the connection relationship between the transmitting end transformer 104 or the receiving end transformer 204 and other circuits, please refer to the above content.

[0139] The power regulating unit 30 is coupled between the input terminal of the wireless power transmission device and the transmitting unit 10 to receive the electric energy Vin.

[0140] The control unit 40 is used to obtain the voltage and current phase difference, the detection signal and the power detection value of the wireless power transmission device of the transmitting unit 10. The operating frequency of the inverter circuit 101 is controlled according to the voltage and current phase difference and the preset phase difference, so that the voltage and current phase difference is equal to the preset phase difference, wherein the operating frequency is near the second resonant frequency point. That is, the control unit 40 is used to compare the voltage and current phase difference with the preset phase difference, and generate a control signal of the inverter circuit 101 according to the comparison result of the voltage and current phase difference and the preset phase difference, and the control signal is used to control the operating frequency of the inverter circuit 101 so that the voltage and current phase difference of the transmitting unit 10 is equal to the preset phase difference.

[0141] The control unit 40 is also used to generate a power reduction signal according to the detection signal, and control the power adjustment unit 30 to adjust the output signal of the wireless power transmission device according to the power reduction signal, the power detection value and the power setting signal. Specifically, the control unit 40 receives the detection signal, and when the detection signal reaches a preset value, the control unit 40 generates a power reduction signal, that is, the power reduction signal is generated only when the detection signal meets the preset condition, wherein the preset value can be set by the control unit 40 internally, or provided by an external circuit. The control unit 40 then generates a power regulation signal according to the power derating signal and the power given signal, wherein the power given signal is the output power signal of the wireless power transmission device under rated conditions, and the power given signal can be provided by an external circuit, such as a voltage DC and current instruction provided by a charging protocol, and the power given signal is calculated according to the voltage instruction and the current instruction, or the voltage instruction and the current instruction are provided by an external battery system, and the power given signal is calculated according to the voltage instruction and the current instruction; or it can be set internally by the control unit 40; and compare the power regulation signal with the power detection value, and generate a control signal according to the comparison result to control the power regulation unit 30 to adjust the output signal of the wireless power transmission device, wherein the output signal includes one or more of the output voltage, the output current, or the output power.

[0142] In this embodiment, the current of the transmitting unit 10 decreases as the output signal decreases; or the voltage of the transmitting unit 10 decreases as the output signal decreases.

[0143] The wireless power transmission device described in the above embodiment can operate with reduced output power, thereby reducing the current or voltage in the transmitting unit 10, reducing losses, reducing the thermal stress of the wireless power transmission device, and ensuring continuous operation of the wireless power transmission device.

[0144] The phase detection unit 60 is coupled to the transmitting unit 10 and the control unit 40 , and is used to obtain the voltage phase signal and the current phase signal of the transmitting unit 10 , and calculate and obtain the voltage-current phase difference according to the voltage phase signal and the current phase signal.

[0145] Combination Figure 7 and Figure 8 The phase detection unit 60 also includes a voltage phase detection unit 61, a current phase detection unit 62 and a phase difference calculation unit 63. The voltage phase detection unit 61 is coupled to the output end of the inverter circuit 101, and is used to detect the voltage phase signal of the transmitting unit 10, that is, the voltage phase signal output by the inverter circuit 101. The current phase detection unit 62 is coupled between the first compensation circuit 102 and the inverter circuit 101, or between the first compensation circuit 102 and the transmitting coil 103, and is used to detect the current phase signal of the transmitting unit 10. The phase difference calculation unit 63 is coupled to the voltage phase detection unit 61 and the current phase detection unit 62, respectively, and is used to obtain the voltage phase signal and the current phase signal, and calculate the voltage and current phase difference according to the voltage phase signal and the current phase signal.

[0146] It should be noted that the phase detection unit 60 may include a voltage phase detection unit and a current detection unit. The voltage detection unit is coupled to the output end of the inverter circuit 101, and is used to detect the voltage phase signal of the transmitting unit; the current detection unit is coupled between the first compensation circuit and the inverter circuit, or between the first compensation circuit and the transmitting coil, and is used to detect the current phase signal of the transmitting unit; the control unit 40 obtains the voltage phase signal and the current phase signal, and generates a voltage-current phase difference according to the voltage phase signal and the current phase signal.

[0147] In the wireless power transmission device provided in the embodiment of the present application, the voltage and current phase difference of the transmitting unit is calculated in real time by the phase detection unit, so that the control unit controls the operating frequency of the inverter circuit so that the voltage and current phase difference is equal to the predetermined phase difference. According to the power given signal and the detected output power of the receiving unit, the wireless power transmission device is operated at a lower output power, and the current in the transmitting coil is reduced, so as to reduce the heat generated by the wireless power transmission device.

[0148] The output power detection unit 70 is coupled to the output end of the wireless power transmission device and the control unit 40, and is used to detect the output power of the wireless power transmission device and provide a power detection value. In this embodiment, the wireless power transmission device may include an output current detection unit and an output voltage detection unit; the output current detection unit is coupled to the output end of the wireless power transmission device and the control unit 40, and is used to detect the output current and provide a current detection value; the transmission voltage detection unit is coupled to the output end of the wireless power transmission device and the control unit 40, and is used to detect the output voltage and provide a voltage detection value; the control unit 40 obtains the current detection value and the voltage detection value, and obtains the power detection value according to the current detection value and the voltage detection value.

[0149] The following is a detailed circuit diagram of the wireless power transmission device. Fig. 9 As shown, the wireless power transmission device includes a transmitting unit 10 , a receiving unit 20 , a power adjustment unit 30 , a phase detection unit 60 , a temperature detection unit 50 , an output power detection unit 70 and a control unit 40 .

[0150] The transmitting unit 10 includes an inverter circuit 101 , a first compensation circuit 102 , and a transmitting coil 103 . In this embodiment, the first compensation circuit 102 is coupled between the inverter circuit 101 and the transmitting coil 103 .

[0151] The receiving unit 20 includes: a receiving coil 201 , a second compensation circuit 202 , a receiving-end transformer 204 , and a rectifier circuit 203 . In this embodiment, the second compensation circuit 202 is coupled between the receiving coil 201 and the rectifier circuit 203 .

[0152] The power regulating unit 30 is coupled between the input power source 80 and the inverter circuit 101 , wherein the input power source 80 may be a DC power source Vin. The control unit 40 is coupled to the power regulating unit 30 and the inverter circuit 101 , respectively.

[0153] Specifically, the power regulation unit 30 is a step-down circuit, which includes a switch Q, a diode D, an inductor L and a bus capacitor C. Bus The first end of the switch Q is connected to one end of the DC power supply Vin, the second end of the switch Q is connected to one end of the inductor L and one end of the diode D respectively, and the bus capacitor C Bus The two ends of the switch Q are connected to the other end of the inductor L and the other end of the diode D respectively. The other end of the diode D is connected to the other end of the DC power supply Vin. The control end of the switch Q is connected to the control unit 40. The inverter circuit 101 is a full-bridge inverter circuit. The input end of the full-bridge inverter circuit is connected to the bus capacitor C Bus The first compensation circuit 102 is a capacitor C1 , which is connected in series between the output end of the full-bridge inverter circuit and the transmitting coil 103 .

[0154] The rectifier circuit 203 of the receiving unit 20 is a full-bridge rectifier circuit. The second compensation circuit 202 is a capacitor C2, which is connected in series to the receiving coil 201 and the input end of the full-bridge rectifier circuit, and the output end of the full-bridge rectifier circuit is connected to the load Bat.

[0155] The temperature detection unit 50 is coupled to the control unit 40 , and is used to detect the ambient temperature or the temperature of components in the wireless power transmission device, and provide a temperature signal.

[0156] The phase detection unit 60 is coupled to the output end of the full-bridge inverter circuit and the control unit 40 to provide a voltage-current phase difference.

[0157] The output power detection unit 70 is coupled to the output terminal of the wireless power transmission device and the control unit 40 to provide a power detection value.

[0158] The control unit 40 is used to receive the voltage-current phase difference provided by the phase detection unit 60. The operating frequency of the inverter circuit 101 is controlled according to the voltage-current phase difference and the preset phase difference, so that the voltage-current phase difference is equal to the preset phase difference. That is, the control unit 40 is used to compare the voltage-current phase difference with the preset phase difference, and generate a control signal of the inverter circuit 101 according to the comparison result of the voltage-current phase difference and the preset phase difference, and the control signal is used to control the operating frequency of the inverter circuit 101 so that the voltage-current phase difference of the transmitting unit 10 is equal to the preset phase difference.

[0159] The control unit 40 is also used to receive the temperature detection signal provided by the temperature detection unit 50, and compare the temperature signal with a preset temperature value. When the temperature signal reaches the preset temperature value, a power reduction signal is generated, wherein the preset temperature value may be the rated operating temperature of the wireless power transmission device, or may be the temperature limit value of the internal components of the wireless power transmission device. The operation of the switch Q of the power adjustment unit 30 is controlled according to the power reduction signal, the power detection value and the power setting signal to adjust the output signal of the wireless power transmission device.

[0160] In this embodiment, the current of the transmitting unit 10 decreases as the output signal decreases; or the voltage of the transmitting unit 10 decreases as the output signal decreases.

[0161] The wireless power transmission device described in the above embodiment can operate with reduced output power, thereby reducing the current or voltage in the transmitting unit 10, reducing losses, reducing the thermal stress of the wireless power transmission device, and ensuring continuous operation of the wireless power transmission device.

[0162] When Fig. 9 When the preset phase difference of the wireless power transmission device shown in FIG. 1 is taken as a typical value of 15 degrees, the following can be obtained: Fig.10 and11 The effect shown. Fig.10 As shown, the horizontal axis is the air gap distance when the transmitting coil and the receiving coil are facing each other, and the larger the value, the larger the air gap distance. The vertical axis is the per-unit value of the current of the transmitting unit 10 (based on the maximum current of the transmitting unit). 100% Load@RV means the current of the transmitting unit when the load is full load and the output voltage is the typical value of the voltage. 50% Load@RV means the current of the transmitting unit when the load is half load and the output voltage is the typical value of the voltage. 100% Load@HV means the current of the transmitting unit when the load is full load and the output voltage is the maximum voltage. 50% Load@HV means the current of the transmitting unit when the load is half load and the output voltage is the maximum voltage. 100% Load@LV means the current of the transmitting unit when the load is full load and the output voltage is the minimum voltage. 50% Load@LV means the current of the transmitting unit when the load is half load and the output voltage is the minimum voltage. As shown Fig.11 As shown, IpHL / IpFL@HV represents the ratio of the current of the transmitter unit when the output voltage is the maximum voltage and the load is half-loaded to the current of the transmitter unit when the output voltage is the maximum voltage and the load is full-loaded. IpHL / IpFL@LV represents the ratio of the current of the transmitter unit when the output voltage is the minimum voltage and the load is half-loaded to the current of the transmitter unit when the output voltage is the minimum voltage and the load is full-loaded. IpHL / IpFL@RV represents the ratio of the current of the transmitter unit when the output voltage is the typical voltage and the load is half-loaded to the current of the transmitter unit when the output voltage is the typical voltage and the load is full-loaded.

[0163] Depend on Fig.10 and Fig.11 It can be seen that under different air gap distances and different output voltage conditions, the current of the transmitting unit 10 can be reduced when the output power decreases, and when the output power is reduced by 50%, the current of the transmitting unit 10 can also be reduced to about 50%, and the loss of the transmitting coil 103 is reduced by about 75%.

[0164] Fig.12 The wireless power transmission device shown is Fig. 9 Most of the circuit structures of the wireless power devices shown are the same, and the acquisition and control methods of the detection signals are also the same, and the same contents will not be repeated here. Fig.12 and Fig. 9 The difference is that: Fig. 9 The transmitter unit 10 of the wireless power device shown in the figure adds a transmitter transformer 104. The transmitter transformer 104 is coupled between the full-bridge inverter circuit and the capacitor C1. The transmitter transformer 104 can play a role in pre-boosting or reducing the voltage, so that the turns ratio of the loosely coupled transformer formed by the transmitting coil 103 and the receiving coil 201 can be closer or even the same, so as to optimize the performance of the loosely coupled transformer and simplify the design.

[0165] Fig.13 The wireless power transmission device shown is Fig. 9 Most of the circuit structures of the wireless power devices shown are the same, and the collection and control methods of the detection signals are also the same, and the same parts will not be repeated here. Fig.13 and Fig. 9 The difference is that: Fig. 9 A receiving-end transformer 204 is added to the receiving unit 20 of the wireless power device shown. The receiving-end transformer 204 is coupled between the full-bridge rectifier circuit and the capacitor C2. The receiving-end transformer 204 can play a role in pre-boosting or reducing the voltage, so that the turns ratio of the loosely coupled transformer formed by the transmitting coil 103 and the receiving coil 201 can be closer or even the same, so as to optimize the performance of the loosely coupled transformer and simplify the design.

[0166] Fig.14 The wireless power transmission device shown is Fig. 9 Most of the circuit structures of the wireless power devices shown are the same, and the collection and control methods of the detection signals are also the same, and the same parts will not be repeated here. Fig.14 and Fig. 9 The difference is that: Fig. 9 The power regulating unit 30 shown in the figure is moved from the input end of the full-bridge inverter circuit to the output end of the full-bridge rectifier circuit, that is, the first end of the switch Q of the power regulating unit 30 and the other end of the diode D are connected to the output capacitor C of the full-bridge rectifier circuit. B The two ends of the bus capacitor C of the power conditioning unit 30 are connected respectively. Bus Connected in parallel across the load Bat.

[0167] Fig.15 The wireless power transmission device shown is Fig. 9 Most of the circuit structures of the wireless power devices shown are the same, and the collection and control methods of the detection signals are also the same, and the same parts will not be repeated here. Fig.15 and Fig. 9 The difference between the first compensation circuit 102 and the second compensation circuit 202 is that the first compensation circuit 102 includes an inductor L s1 and capacitor C1, the second compensation circuit 202 includes L s2 and capacitor C2, where the inductor L s1 The capacitor C1 is connected in series between the full-bridge inverter circuit and the transmitting coil 103, and the capacitor C1 is connected in parallel between the two ends of the transmitting coil 103; the inductor L s2 The capacitor C2 is connected in series between the full-bridge rectifier circuit and the receiving coil 201 , and is connected in parallel between both ends of the receiving coil 201 .

[0168] Fig.16The wireless power transmission device shown is Fig. 9 Most of the circuit structures of the wireless power devices shown are the same, and the collection and control methods of the detection signals are also the same, and the same parts will not be repeated here. Fig.16 and Fig. 9 The difference between the first compensation circuit 102 and the second compensation circuit 202 is that the first compensation circuit 102 includes an inductor L s1 , capacitor C1 and capacitor C s1 , the second compensation circuit 202 includes L s2 , capacitor C2 and capacitor C s2 , where the inductor L s1 One end of the inductor L is connected to an output end of the full-bridge inverter circuit. s1 The other end of the capacitor is connected to one end of capacitor C1 and capacitor C s1 One end of the capacitor C s1 The other end of the receiving coil 201 is connected to one end of the transmitting coil 103, and the other end of the transmitting coil 103 is connected to the other end of the capacitor C1 and the other output end of the full-bridge inverter circuit; one end of the receiving coil 201 is connected to the capacitor C s2 One end of the capacitor C s2 The other end of the inductor L s2 and one end of capacitor C2, and the inductor L s2 The other end of is connected to an input end of the full-bridge rectifier circuit, and the other end of the receiving coil 201 is connected to the other end of the capacitor C2 and the other input end of the full-bridge rectifier circuit respectively.

[0169] Fig.17 The wireless power transmission device shown is Fig. 9 Most of the circuit structures of the wireless power devices shown are the same, and the collection and control methods of the detection signals are also the same, and the same parts will not be repeated here. Fig.17 and Fig. 9 The difference between the first compensation circuit 102 and the second compensation circuit 202 is that the first compensation circuit 102 includes a capacitor C1, and the second compensation circuit 202 includes a capacitor C2. The capacitor C1 is connected in parallel to both ends of the transmitting coil 103, and the capacitor C2 is connected in parallel to both ends of the receiving coil 201.

[0170] Fig.18 The wireless power transmission device shown is Fig. 9 The circuit structures of the wireless power devices shown are the same, and the control methods are also the same, and the same parts will not be repeated here. Fig.18 and Fig. 9 The difference is that the detection signal is collected differently. Fig.18As shown, the wireless power transmission device includes a duration detection unit 100. The duration detection unit 100 can be a timer in the control unit 40, or it can be an independent timing circuit, which is coupled to the control unit 40 to provide a duration signal, and the duration signal indicates the working duration of the wireless power transmission device. The control unit 40 receives the duration signal and compares the duration signal with a preset duration signal. When the duration signal reaches the preset duration signal, the power reduction signal is generated.

[0171] like Fig.19 As shown, another embodiment of the present application provides a control method for a wireless power transmission device, and the method is applied to the wireless power transmission device in the above embodiment. The method includes the following steps:

[0172] S801. The control unit obtains a detection signal.

[0173] The detection signal may be the temperature of components inside the device or the temperature of the environment in which the device is located. The detection signal may also be a duration signal of the working duration of the device.

[0174] S808. The control unit obtains the voltage and current phase difference of the transmitting unit.

[0175] The voltage-current phase difference of the transmitting unit can be obtained in the following manner: a voltage phase signal of the transmitting unit and a current phase signal of the transmitting unit are obtained, and the voltage-current phase difference is calculated according to the voltage phase signal and the current phase signal.

[0176] S803: The control unit obtains a power detection value.

[0177] The power detection value can be obtained by directly collecting the output power of the output end of the device through the sensor. The power detection value can also be obtained by calculation. Specifically, the power detection value is obtained by calculating the following method: obtaining the current detection value and the voltage detection value. The power detection value is calculated based on the current detection value and the voltage detection value.

[0178] S804, the control unit controls the operating frequency of the inverter circuit according to the voltage-current phase difference signal and the preset phase difference signal, so that the voltage-current phase difference is equal to the preset phase difference signal, generates a derating signal according to the detection signal, and controls the power regulating unit to regulate the output signal of the wireless power transmission device according to the derating signal, the power detection value and the power given signal.

[0179] Among them, the controller controls the operating frequency of the inverter circuit according to the voltage-current phase difference and the preset phase difference, wherein the operating frequency is the frequency corresponding to the preset phase difference, so that the operating frequency of the inverter circuit is greater than the second resonant frequency point, the operating frequency is equal to the second resonant frequency point, or the operating frequency is less than the second resonant frequency point and greater than the first resonant frequency point, so that the voltage-current phase difference of the transmitting unit is equal to the preset phase difference signal.

[0180] Generate a derating signal according to the detection signal, and control the power adjustment unit to adjust the output signal of the wireless power transmission device according to the derating signal, the power detection value and the power given signal, specifically including:

[0181] When the detection signal reaches a preset value, a power reduction signal is generated. After the power reduction signal is obtained, a power adjustment signal is provided according to the power reduction signal and the power given signal. According to the power adjustment signal and the power detection value, the power adjustment unit is controlled to reduce the output signal, thereby reducing the current of the transmitting unit or reducing the voltage of the transmitting unit. The heat generated by the wireless power transmission device is reduced, and the heating rate is reduced, so that the wireless power transmission device can work under conditions beyond the rated working conditions.

[0182] As a specific implementation, the detection signal is a temperature signal, and the preset value is a preset temperature value. The control unit generates a power derating signal when the temperature signal reaches the preset temperature value. The preset temperature value may be the rated operating temperature of the wireless power transmission device, or may be the limiting temperature of the internal components of the device. Then, the output signal of the control device is controlled according to the power derating signal and other information, so that the wireless power transmission device can operate at a temperature exceeding the preset temperature.

[0183] As another specific implementation of the control unit, the detection signal is a duration signal, and the preset value is a preset duration signal. The control unit is used to generate a derating signal when the duration signal reaches the preset duration signal. The preset duration signal is the rated working duration of the wireless power transmission device. Then, according to the derating signal and other information, the output signal of the control device is controlled, so that the wireless power transmission device can work beyond the preset duration.

[0184] In the temperature control method provided in the embodiment of the present application, the operating frequency of the inverter circuit is controlled so that the voltage-current phase difference of the transmitting unit is equal to the predetermined phase difference, so that the current in the transmitting coil can be controlled by the output signal of the wireless power transmission device, and the output signal of the wireless power transmission device is controlled and adjusted so that the wireless power transmission device can reduce the output power operation, reduce the loss, and reduce the heat generation of the device, thereby enabling the wireless power transmission device to operate beyond the rated operating conditions.

[0185] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A wireless power transmission device, characterized in that: include: A transmitting unit, comprising an inverter circuit, a first compensation circuit and a transmitting coil; The first compensation circuit is coupled between the inverter circuit and the transmitting coil; A receiving unit, comprising a receiving coil, a second compensation circuit and a rectifier circuit; the second compensation circuit is coupled between the receiving coil and the rectifier circuit; A power regulating unit, used for regulating the output signal of the wireless power transmission device; as well as A control unit, coupled to the inverter circuit and the power adjustment unit, respectively, and configured to obtain a voltage-current phase difference, a detection signal, and a power detection value of the wireless power transmission device of the transmitting unit; control an operating frequency of the inverter circuit according to the voltage-current phase difference and a preset phase difference, so that the voltage-current phase difference is equal to the preset phase difference; generate a power derating signal according to the detection signal, and control the power adjustment unit to adjust the output signal according to the power derating signal, the power detection value, and the power setting signal; The first compensation circuit, the transmitting coil, the receiving coil and the second compensation circuit constitute a resonant network; The resonant network includes a first resonant frequency point, a second resonant frequency point and a third resonant frequency point, wherein the second resonant frequency point is greater than the first resonant frequency point, and the first resonant frequency point is greater than the third resonant frequency point; The operating frequency is greater than the second resonant frequency point, the operating frequency is equal to the second resonant frequency point, or the operating frequency is less than the second resonant frequency point and greater than the first resonant frequency point.

2. The wireless power transmission device according to claim 1, characterized in that: The wireless power transmission device further includes: a phase detection unit; The phase detection unit is coupled to the transmitting unit and the control unit, and is used to obtain the voltage phase signal and the current phase signal of the transmitting unit, and calculate the voltage-current phase difference according to the voltage phase signal and the current phase signal.

3. The wireless power transmission device according to claim 2, characterized in that: The phase detection unit includes: a voltage phase detection unit, a current phase detection unit and a phase difference calculation unit; The voltage phase detection unit is coupled to the output end of the inverter circuit, and is used to detect the voltage phase signal of the transmitting unit; The current phase detection unit is coupled between the inverter circuit and the first compensation circuit, or between the first compensation circuit and the transmitting coil, and is used to detect the current phase signal of the transmitting unit; The phase difference calculation unit is used to obtain the voltage phase signal and the current phase signal, and calculate the voltage-current phase difference according to the voltage phase signal and the current phase signal.

4. The wireless power transmission device according to claim 1, characterized in that: The control unit is specifically used for: When the detection signal reaches a preset value, the power derating signal is generated, a power adjustment signal is provided according to the power derating signal and the power given signal, and the power adjustment unit is controlled to reduce the output signal according to the power adjustment signal and the power detection value, thereby reducing the current of the transmitting unit or reducing the voltage of the transmitting unit.

5. The wireless power transmission device according to claim 1, characterized in that: The detection signal is a temperature signal, and the preset value is a preset temperature value; The control unit is used for generating the power derating signal when the temperature signal reaches the preset temperature value.

6. The wireless power transmission device according to claim 1, characterized in that: The detection signal is a duration signal, and the preset value is a preset duration signal; The control unit is used for generating the power reduction signal when the duration signal reaches the preset duration signal.

7. The wireless power transmission device according to claim 5, characterized in that: Also includes: Temperature detection unit; The temperature detection unit is coupled to the control unit, and is used to detect the ambient temperature or the temperature of the components of the wireless power transmission device, and provide the temperature signal.

8. The wireless power transmission device according to claim 1, characterized in that: Also includes: Output power detection unit; The output power detection unit is coupled to the output end of the wireless power transmission device and the control unit, and is used to detect the output power of the wireless power transmission device and provide the power detection value.

9. The wireless power transmission device according to claim 1, characterized in that: Also includes: An output current detection unit and an output voltage detection unit; The output current detection unit is coupled to the output end of the wireless power transmission device and the control unit, and is used to detect the output current of the wireless power transmission device and provide a current detection value; The output voltage detection unit is coupled to the output end of the wireless power transmission device and the control unit, and is used to detect the output voltage of the wireless power transmission device and provide a voltage detection value; The control unit is used to obtain the current detection value and the voltage detection value, and obtain the power detection value according to the current detection value and the voltage detection value.

10. The wireless power transmission device according to claim 1, characterized in that: The output signal includes one or more of output current, output voltage, or output power.

11. The wireless power transmission device according to claim 1, characterized in that: The power regulation unit includes any one of a buck circuit, a boost circuit or a buck-boost circuit.

12. The wireless power transmission device according to claim 1, characterized in that: The power regulating unit is electrically coupled between the input terminal of the wireless power transmission device and the transmitting unit; or, The power regulating unit is electrically coupled between the receiving unit and the output end of the wireless power transmission device.

13. The wireless power transmission device according to claim 1, characterized in that: The transmitting unit also includes a transmitting end transformer; The transmitter transformer is coupled between the inverter circuit and the first compensation circuit; or, The transmitting-end transformer is coupled between the first compensation circuit and the transmitting coil.

14. The wireless power transmission device according to claim 1, characterized in that: The receiving unit further includes: a receiving end transformer; The receiving-end transformer is coupled between the receiving coil and the second compensation circuit; or, The receiving-end transformer is coupled between the second compensation circuit and the rectifier circuit.

15. A control method for a wireless power transmission device, characterized in that: The method is applied to the wireless power transmission device according to any one of claims 1 to 14; the method comprises: Get the detection signal; Obtaining a voltage and current phase difference of the transmitting unit; Get the power detection value; The operating frequency of the inverter circuit is controlled according to the voltage-current phase difference and the preset phase difference, so that the voltage-current phase difference is equal to the preset phase difference, a power derating signal is generated according to the detection signal, and the power regulating unit is controlled to adjust the output signal of the wireless power transmission device according to the power derating signal, the power detection value and the power given signal.

16. The control method of the wireless power transmission device according to claim 15, characterized in that: Obtaining the voltage and current phase difference of the transmitting unit specifically includes: Acquire a voltage phase signal of a transmitting unit; Acquire the current phase signal of the transmitting unit; The voltage-current phase difference is obtained by calculation according to the voltage phase signal and the current phase signal.

17. The control method of the wireless power transmission device according to claim 15, characterized in that: Generating a power reduction signal according to the detection signal, and controlling the power adjustment unit to adjust the output signal of the wireless power transmission device according to the power reduction signal, the power detection value and the power given signal, specifically includes: When the detection signal reaches a preset value, the power derating signal is generated, a power adjustment signal is provided according to the power derating signal and the power given signal, and the power adjustment unit is controlled to reduce the output signal according to the power adjustment signal and the power detection value, thereby reducing the current of the transmitting unit or reducing the voltage of the transmitting unit.

18. The control method of the wireless power transmission device according to claim 17, characterized in that: The detection signal is a temperature signal, and the preset value is a preset temperature value; The power derating signal is generated when the temperature signal reaches the preset temperature value.

19. The control method of the wireless power transmission device according to claim 15, characterized in that: Get the power detection value, including: Get the current detection value; Get the voltage detection value; The power detection value is obtained by calculation according to the current detection value and the voltage detection value.

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