Bidirectional wireless power transmission system and wide-range soft switching control method

Abstract

A bidirectional wireless power transmission system and a wide range soft switch control method belong to the field of bidirectional wireless power transmission technology. The present invention addresses the problem of large switching loss in bidirectional wireless power transmission systems. The system includes a DC input voltage U DC , inverter circuit, first auxiliary network, input electrolytic capacitor C O1 , transmitter compensation network, coupling mechanism, receiver compensation network, rectifier circuit, second auxiliary network, output electrolytic capacitor C O2 and charging voltage U BAT ; At DC input voltage U DC An input electrolytic capacitor C is set in parallel between the inverter circuit O1 and the first auxiliary network; the inverter circuit is connected to the coupling mechanism via the transmitter compensation network, and the coupling mechanism is then connected to the rectifier circuit via the receiver compensation network; in the rectifier circuit and the charging voltage U BAT The second auxiliary network is set in parallel between the output electrolytic capacitor C O2 The present invention can realize wide range soft switching control.

Description

Technical Field

[0001] The present invention relates to a bidirectional wireless power transmission system and a wide-range soft switch control method, belonging to the technical field of bidirectional wireless power transmission. Background Art

[0002] In recent years, with the growing demand for wireless charging of electronic devices, bidirectional wireless power transmission technology has gradually entered the public eye. In areas such as electric vehicles, industrial robots, smart furniture, and the Internet of Things, bidirectional wireless power transmission technology can effectively enable device charging and energy recovery, achieving a two-way flow of energy. Compared to unidirectional wireless power transmission technology, bidirectional wireless power transmission can dynamically adjust the direction and amount of energy transmission based on load demand and power supply conditions. In a multi-load system, when the power demand of some loads suddenly changes, the system can promptly obtain energy from other power sources or energy storage units, avoiding large voltage fluctuations caused by the inability of a single power supply to respond in a timely manner and ensuring voltage stability at the load end. Furthermore, because bidirectional wireless power transmission systems allow for more flexible control of energy transmission, they can better control the current and voltage waveforms during power regulation, effectively reducing harmonic content and improving power quality.

[0003] Bidirectional wireless power transmission technology is currently widely used in smart microgrids and implantable medical devices. For example, smart microgrid applications typically include a variety of distributed energy sources and energy storage devices, as well as different types of loads. Bidirectional wireless power transmission technology can achieve flexible energy interaction between distributed energy sources and energy storage devices, energy storage devices and loads, and loads and loads, optimize energy distribution and utilization efficiency within the microgrid, improve the stability and reliability of the microgrid, and support smooth switching between isolated and grid-connected operation modes. In implantable medical devices, such as pacemakers, bidirectional wireless power transmission technology can not only achieve external wireless charging of the implanted device, but also transmit information such as physiological data collected by the implanted device back to the external device via a wireless energy transmission link, realizing two-way transmission of energy and data, reducing the need for additional communication lines and interfaces, reducing the risk of infection, and improving the safety and reliability of the device.

[0004] For bidirectional wireless power transmission systems, power losses are primarily concentrated in the coupling coil and power converter. However, bidirectional wireless power transmission typically operates at a relatively high system frequency and in resonant mode, resulting in switching losses in high-frequency switching devices contributing significantly to the system's total losses. Therefore, reducing switching losses in bidirectional wireless power transmission systems is an important approach to improving system efficiency.

[0005] There are three main technical means to improve switching losses. The first is a dual phase-shift modulation strategy, which changes the transmission power by adjusting the internal phase-shift angle of the primary and secondary full-bridges. At the same time, bilateral modulation can reduce current stress, but the soft switching range of this method is limited. The second is a triple phase-shift modulation strategy, which adds the freedom of the external phase-shift angle between the primary and secondary voltages on the basis of dual phase shift, thereby achieving a wide range of zero-voltage turn-on of the system. However, when the system transmission power decreases, the external phase-shift angle continues to increase, resulting in increased conduction losses. The third is a control method based on adjustable elements, which adjusts the inductance (capacitance) by adding an adjustable inductor (capacitor) at the input end. While changing the output power, it makes the system inductive to achieve zero-voltage turn-on. However, this solution has a complex structure and high cost.

[0006] To address these issues, an article titled "Pulse Density Modulated ZVS Full-Bridge Converters for Wireless Power Transfer Systems" in Volume 34, Issue 1 of IEEE Transactions on Power Electronics discloses a soft-switching control method for a bidirectional wireless power transfer system based on an LC series resonant circuit. This method improves the soft-switching range of the bidirectional wireless power transfer system, but still has the following shortcomings: 1) The total loss of the LC series resonant circuit is greater than the improved switching loss, significantly affecting the overall system efficiency; 2) The resonant current in the auxiliary network is uncontrollable, complicating the commutation process; 3) The soft-switching range of the switch tube is not within the full charging range, and the main switch tube still has turn-off losses; and 4) The implementation of soft switching is susceptible to changes in compensation parameter values.

[0007] Therefore, the soft switching stability of bidirectional wireless power transfer systems needs to be improved urgently. Summary of the Invention

[0008] In order to solve the problem of large switching loss in a bidirectional wireless power transmission system, the present invention provides a bidirectional wireless power transmission system and a wide-range soft switching control method.

[0009] A bidirectional wireless power transmission system of the present invention includes a DC input voltage U DC , inverter circuit, first auxiliary network, input electrolytic capacitor C O1 , transmitter compensation network, coupling mechanism, receiver compensation network, rectifier circuit, second auxiliary network, output electrolytic capacitor C O2 and charging voltage U BAT ;

[0010] At the DC input voltage U DCAn input electrolytic capacitor C is set in parallel between the inverter circuit O1 and the first auxiliary network; the inverter circuit is connected to the coupling mechanism via the transmitter compensation network, and the coupling mechanism is then connected to the rectifier circuit via the receiver compensation network; in the rectifier circuit and the charging voltage U BAT The second auxiliary network is set in parallel between the output electrolytic capacitor C O2 ;

[0011] The first auxiliary network is supplied with a DC input voltage U DC The circuit structure of the inverter circuit side and the second auxiliary network are connected by the charging voltage U BAT The circuit structure of the rectifier circuit side is the same as that of the rectifier circuit side; the first auxiliary network includes a switch tube S A1 , switch tube S A2 、Inductor L A , capacitor C A1 , capacitor C A2 , diode D A1 and diode D A2 , using the switch tube S A1 and switch tube S A2 For inductance L A , capacitor C A1 and capacitor C A2 The resonant state is controlled to provide the necessary conditions for realizing full range soft switching of the inverter switch tube. A1 and diode D A2 Realize the energy feedback function; the second auxiliary network includes the switch tube S B1 , switch tube S B2 、Inductor L B , capacitor C B1 , capacitor C B2 , diode D B1 and diode D B2 , using the switch tube S B1 and switch tube S B2 For inductance L B , capacitor C B1 and capacitor C B2 The resonant state is controlled to provide the necessary conditions for achieving full range soft switching of the rectifier switch tube. B1 and diode D B2 Realize energy feedback function;

[0012] The first auxiliary network also includes a switch tube S A3 ;

[0013] DC input voltage U DC The positive terminal of the input electrolytic capacitor C O1 One end, DC input voltage U DCThe negative terminal of the input electrolytic capacitor C O1 The other end; DC input voltage U DC The cathode of the diode D is connected A1 The anode and capacitor C A1 One end of the diode D A1 The cathode of the diode D is connected A2 The anode and capacitor C A2 One end of the diode D A2 The cathode connection inductance L A One end of the inductor L A The other end of the capacitor C A1 The other end and capacitor C A2 the other end;

[0014] Diode D A2 The cathode of the switch tube S is connected A2 The source of the switch tube S A2 The drain of the switch tube S A1 The drain of the switch tube S A1 The source of the switch tube S A3 The source of the switch tube S A3 The drain connection inductance L A the other end.

[0015] According to the bidirectional wireless power transmission system of the present invention, the inverter circuit includes a switch tube MOSFETS1, a switch tube MOSFETS2, a switch tube MOSFETS3 and a switch tube MOSFETS4, and the drain of the switch tube MOSFETS1 is connected to the switch tube S A3 The source of the switch tube MOSFETS1 is connected to the drain of the switch tube MOSFETS2, and the source of the switch tube MOSFETS2 is connected to the DC input voltage U DC The source of the switching tube MOSFETS2 is connected to the source of the switching tube MOSFETS4, the drain of the switching tube MOSFETS4 is connected to the source of the switching tube MOSFETS3, and the drain of the switching tube MOSFETS3 is connected to the drain of the switching tube MOSFETS1.

[0016] According to the bidirectional wireless power transmission system of the present invention, the transmitter compensation network includes a transmitter side compensation inductor L P1 , transmitter side compensation capacitor C P1 and the transmitter side compensation capacitor C P ;

[0017] The source of the switch tube MOSFETS1 is connected to the emitter side compensation inductor L P1 One end of the transmitter side compensation inductor L P1 The other end is connected to the transmitter side compensation capacitor C P1One end of the transmitter side compensation capacitor C P1 The other end is connected to the drain of the switch tube MOSFETS4; the transmitter side compensation inductor L P1 The other end is connected to the transmitter side compensation capacitor C P One end of the transmitter side compensation capacitor C P The other end is used to connect an input connection end of the coupling mechanism, the transmitter side compensation capacitor C P1 The other end is used to connect to another input connection end of the coupling mechanism.

[0018] According to the bidirectional wireless power transmission system of the present invention, the coupling mechanism includes a transmitting side and a receiving side, and the transmitting side includes a transmitting coil L P , the receiving side includes a receiving coil L S ;

[0019] Transmitting coil L P The same-name end is connected to the transmitter side compensation capacitor C P The other end of the transmitting coil L P The opposite end is connected to the drain of the switch tube MOSFETS4;

[0020] Receiving coil L S The same-name terminal is used as a connection terminal of the receiving compensation network, and the receiving coil L S The opposite end of the terminal serves as the other connection end of the receiving end compensation network.

[0021] According to the bidirectional wireless power transmission system of the present invention, the receiving side compensation capacitor C of the receiving end compensation network S , receiving side compensation inductor L S1 and the receiving side compensation capacitor C S1 ;

[0022] Receiving coil L S The same-name end is connected to the receiving side compensation capacitor C S One end of the receiving side compensation capacitor C S The other end is connected to the receiving side compensation capacitor C S1 One end of the receiving side compensation capacitor C S1 The other end is connected to the receiving coil L S The opposite end of the receiving side compensation capacitor C S The other end is connected to the receiving side compensation inductor L S1 One end of the receiving side, the compensation inductor L S1 The other end is used as a connection end of the rectifier circuit, and the receiving side compensation capacitor C S1 The other end serves as the other connection end of the rectifier circuit.

[0023] According to the bidirectional wireless power transmission system of the present invention, the rectifier circuit includes switch tubes MOSFETS5, MOSFETS6, MOSFETS7 and MOSFETS8, and the receiving side compensation inductor L S1 The other end is connected to the source of the switch tube MOSFETS5, the drain of the switch tube MOSFETS5 is connected to the drain of the switch tube MOSFETS7, and the source of the switch tube MOSFETS7 is connected to the receiving side compensation capacitor C S1 The other end is connected to the drain of the switching tube MOSFETS8, the source of the switching tube MOSFETS8 is connected to the source of the switching tube MOSFETS6, and the drain of the switching tube MOSFETS6 is connected to the source of the switching tube MOSFETS5.

[0024] According to the bidirectional wireless power transmission system of the present invention, the second auxiliary network further includes a switch tube S B3 ;

[0025] Switching tube S B1 The source of the switch tube MOSFETS7 is connected to the drain of the switch tube S B3 The source of the switch tube S B1 The drain of the switch tube S B2 The drain of the switch tube S B2 The source connection inductor L B One end of the inductor L B The other end is connected to the switch tube S B3 The drain and capacitor C B1 One end of the capacitor C B1 The other end is connected to the source of the switch tube MOSFETS8;

[0026] Switching tube S B2 The source of the diode D B2 The cathode of diode D B2 The anode connection capacitance C B2 One end and diode D B1 The cathode of the capacitor C B2 The other end of the inductor L B The other end of the diode D B1 The anode is connected to the source of the switching tube MOSFETS8;

[0027] Switching tube S B1 The drain of the output electrolytic capacitor C O2 One end and charging voltage U BAT The positive electrode of the output electrolytic capacitor C O2 The other end is connected to the source of the switch tube MOSFETS8 and the charging voltage U BAT of the negative electrode.

[0028] The present invention also provides a wide-range soft switching control method for a bidirectional wireless power transmission system, which is used to control the switching of the bidirectional wireless power transmission system, comprising:

[0029] The soft switching commutation principle of the charging mode and the discharging mode of the bidirectional wireless power transmission system is the same; the soft switching control of the charging mode in one switching cycle includes nine soft switching commutation modes:

[0030] Mode 1 [0~t0]: Make the switch S A1 On, DC input voltage U DC Through the switch tube S A1 and the switch MOSFETS1 to supply energy to the first auxiliary network until the capacitor C A1 Voltage u across both ends CA1 and capacitor C A2 Voltage u across both ends CA2 The value of U DC , reaching the moment t0; at the moment t0, the switch tube S A1 Turn off and make the switch tube S A3 conduction;

[0031] Mode 2 [t0~t1]: At time t0, the capacitor C A1 and capacitor C A2 For switch tube S A1 Voltage u across both ends SA1 The rising rate of the switch tube S A1 Achieve zero voltage shutdown; at this time, the switch tube S A3 Voltage u across both ends SA3 is zero, the switch tube S A3 Achieve zero voltage turn-on; then, the capacitor C A1 and capacitor C A2 Start discharging, capacitor C A1 Voltage u across both ends CA1 and capacitor C A2 Voltage u across both ends CA2 It decreases linearly to zero and reaches time t1;

[0032] Mode 3 [t1~t2]: At t1, the DC bus voltage has dropped to zero, and the switch tubes MOSFETS1, MOSFETS2 and MOSFETS4 perform zero-loss switching. S 3 is in the off state until the switching is completed and reaches time t2; the duration of [t1~t2] is not less than the dead zone working time of the system;

[0033] Mode 4 [t2~t3]: At time t2, the switch tube S A2 conduction, inductance L A Limit switch tube SA2 The current i during conduction SA2 , so that the switch tube S A2 Achieve zero current conduction; inductor L A The voltage across the two ends u LA For U DC , flows through the inductor L A The current i LA Increase linearly until the current i LA rises to a value equal to the current flowing through the transmitter-side compensation inductor L P1 The current I0 reaches the moment t3;

[0034] Mode 5 [t3~t4]: At time t3, the inductor L A and capacitor C A1 Resonance, in charging state, flowing through inductor L A The current i LA and capacitor C A1 Voltage u across both ends CA1 increases nonlinearly until the capacitance C A1 Voltage u across both ends CA1 Rise to U DC , reaching time t4;

[0035] Mode 6 [t4~t5]: At time t4, the inductor L A and capacitor C A1 Resonance ends; inductance L A , switch tube S A1 The body diode and switch tube S A2 and switch tube S A3 A circulation loop is formed, reaching time t5;

[0036] Mode 7 [t5~t6]: At t5, the switch S A2 Turn off; capacitor C A2 Limits the switch S A2 The voltage change rate at both ends of the switch at the time of shutdown makes the switch tube S A2 Achieve zero voltage shutdown; inductor L A and capacitor C A2 Resonance, inductance L A Release electrical energy, capacitor C A2 In charging mode, current flows through the inductor L A The current i LA Nonlinearity decreases, capacitance C A2 Voltage u across both ends CA2 The nonlinearity increases until the switch tube S A2 The voltage across the two ends is equal to U DC , reaching time t6;

[0037] Mode 8 [t6~t7]: At time t6, the inductor LA and capacitor C A2 Resonance ends, inductor L A The voltage across the terminals remains at U DC , inductance L A Release electrical energy and flow through inductor L A The current i LA Linearly decreasing, current flows through the inductor L at time t6 A The current i LA Greater than the current flowing through the transmitter side compensation inductor L P1 The current I0 begins to flow through the switch tube S A1 until the current flows through the inductor L A The current i LA Linearly decreases to equal the current flowing through the transmitter side compensation inductor L P1 The current I0 of the switch tube S A1 The body diode freewheeling ends and reaches the moment t7;

[0038] Mode 9 [t7~t8]: At t7, the inductor L A The voltage across the two ends remains U DC , flows through the inductor L A The current i LA It continues to decrease linearly until it reaches zero, and at time t8, a switching cycle ends.

[0039] Beneficial effects of the present invention: The present invention improves the bidirectional wireless power transmission system with the help of an active auxiliary network, and can improve the soft switching stability of the system through commutation control.

[0040] The present invention implements wide-range soft switching of a bidirectional wireless power transmission system based on an active auxiliary network. This completely eliminates switching losses of the main switch during wireless charging and discharging, and the soft switching operates over the full load range. The auxiliary switch tubes in the active auxiliary network lack parallel auxiliary resonant capacitors, thus avoiding potential adverse effects on switch safety caused by sudden discharge of the parallel resonant capacitors with surges. During a DC bus voltage drop, the system relies solely on energy transfer between the resonant capacitors, rather than a resonant state. Therefore, during a DC bus voltage drop, only the current of the compensation inductor flows through the active auxiliary circuit, reducing losses in the auxiliary circuit and significantly improving the efficiency of the bidirectional wireless power transmission system, particularly under light load conditions.

[0041] The system of the present invention can realize soft switching under light load conditions, is not affected by changes in compensation parameters, and can achieve wide-range soft switching control. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a circuit topology diagram of the bidirectional wireless power transmission system of the present invention;PS is the transmitting coil L P and receiving coil L S The mutual inductance between CB1 is the capacitance C B1 Voltage across both ends, u CB2 is the capacitance C B2 Voltage across both ends, i LB is the current flowing through the inductor L B Point A is the connection point between the switch MOSFETS1 and the switch MOSFETS2, point B is the connection point between the switch MOSFETS3 and the switch MOSFETS4, point C is the connection point between the switch MOSFETS5 and the switch MOSFETS6, and point D is the connection point between the switch MOSFETS7 and the switch MOSFETS8.

[0043] Figures 2 to 10 This is an equivalent circuit diagram of nine modes of the soft switching commutation process in one switching cycle in the charging mode of the wide-range soft switching control method of the bidirectional wireless power transmission system of the present invention; Figure 2 is the equivalent circuit diagram of commutation process mode 1; Figure 3 is the equivalent circuit diagram of commutation process mode 2; Figure 4 is the equivalent circuit diagram of commutation process mode three; Figure 5 is the equivalent circuit diagram of commutation process mode four; Figure 6 is the equivalent circuit diagram of commutation process mode five; Figure 7 is the equivalent circuit diagram of commutation process mode six; Figure 8 is the equivalent circuit diagram of commutation process mode seven; Figure 9 is the equivalent circuit diagram of commutation process mode eight; Figure 10 The equivalent circuit diagram of the commutation process mode nine; U AB is the voltage between points AB;

[0044] Figure 11 This is a characteristic working waveform diagram of nine key components of the working mode in one switching cycle of the wide range soft switching control method of the bidirectional wireless power transmission system of the present invention; gS1 Indicates the driving voltage of the switch tube MOSFETS1, u gS2 Indicates the driving voltage of the switch tube MOSFETS2, u gSA1 Indicates the switch tube S A1 The driving voltage, u gSA2 Indicates the switch tube S A2 The driving voltage, u gSA3 Indicates the switch tube S A3 The driving voltage, u DA1 Represents diode D A1 Voltage across both ends, i DA2Indicates that the current flowing through diode D A2 The current, u DA2 Represents diode D A Voltage across both ends 2, u SA2 Indicates the switch tube S A2 Voltage across both ends, i SA1 Indicates that the current flowing through the switch tube S A1 The current, u SA1 Indicates the switch tube S A1 Voltage across both ends, i SA3 Indicates that the current flowing through the switch tube S A3 Current;

[0045] Figure 12 In the wide range soft switch control method of the bidirectional wireless power transmission system of the present invention, u SA1 and i SA1 The simulation waveform diagram of

[0046] Figure 13 In the wide range soft switch control method of the bidirectional wireless power transmission system of the present invention, u SA2 and flows through the switch tube S A2 The current i SA2 The simulation waveform diagram of

[0047] Figure 14 In the wide range soft switch control method of the bidirectional wireless power transmission system of the present invention, the switch tube S A3 Voltage u across both ends SA3 and i SA3 The simulation waveform diagram of

[0048] Figure 15 In the wide range soft switch control method of the bidirectional wireless power transmission system of the present invention, u CA1 、u CA2 and i LA . DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0050] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0051] The present invention will be further described below with reference to the accompanying drawings, but is not intended to limit the present invention.

[0052] Specific implementation method 1. Combination Figure 1 As shown, the present invention provides a bidirectional wireless power transmission system, including a DC input voltage U DC , inverter circuit, first auxiliary network, input electrolytic capacitor C O1 , transmitter compensation network, coupling mechanism, receiver compensation network, rectifier circuit, second auxiliary network, output electrolytic capacitor C O2 and charging voltage U BAT ;

[0053] At the DC input voltage U DC An input electrolytic capacitor C is set in parallel between the inverter circuit O1 and the first auxiliary network; the inverter circuit is connected to the coupling mechanism via the transmitter compensation network, and the coupling mechanism is then connected to the rectifier circuit via the receiver compensation network; in the rectifier circuit and the charging voltage U BAT The second auxiliary network is set in parallel between the output electrolytic capacitor C O2 ;

[0054] The first auxiliary network is supplied with a DC input voltage U DC The circuit structure of the inverter circuit side and the second auxiliary network are connected by the charging voltage U BAT The circuit structure of the rectifier circuit side is the same as that of the rectifier circuit side; the first auxiliary network includes a switch tube S A1 , switch tube S A2 、Inductor L A , capacitor C A1 , capacitor C A2 , diode D A1 and diode D A2 , using the switch tube S A1 and switch tube S A2 For inductance L A , capacitor C A1 and capacitor C A2 The resonant state is controlled to provide the necessary conditions for realizing full range soft switching of the inverter switch tube. A1 and diode D A2 Realize the energy feedback function; the second auxiliary network includes the switch tube S B1 , switch tube S B2 、Inductor L B , capacitor C B1 , capacitor C B2 , diode D B1 and diode D B2 , using the switch tube S B1 and switch tube S B2 For inductance L B , capacitor C B1 and capacitor CB2 The resonant state is controlled to provide the necessary conditions for achieving full range soft switching of the rectifier switch tube. B1 and diode D B2 Realize energy feedback function.

[0055] Furthermore, the first auxiliary network further includes a switch tube S A3 ;

[0056] DC input voltage U DC The positive terminal of the input electrolytic capacitor C O1 One end, DC input voltage U DC The negative terminal of the input electrolytic capacitor C O1 The other end; DC input voltage U DC The cathode of the diode D is connected A1 The anode and capacitor C A1 One end of the diode D A1 The cathode of the diode D is connected A2 The anode and capacitor C A2 One end of the diode D A2 The cathode connection inductance L A One end of the inductor L A The other end of the capacitor C A1 The other end and capacitor C A2 the other end;

[0057] Diode D A2 The cathode of the switch tube S is connected A2 The source of the switch tube S A2 The drain of the switch tube S A1 The drain of the switch tube S A1 The source of the switch tube S A3 The source of the switch tube S A3 The drain connection inductance L A the other end.

[0058] This embodiment is based on an active auxiliary network, and the soft switch can operate within the full load range, especially under light load conditions, which significantly improves the efficiency of the bidirectional wireless power transmission system.

[0059] The inverter circuit includes a switch tube MOSFETS1, a switch tube MOSFETS2, a switch tube MOSFETS3 and a switch tube MOSFETS4. The switch tube MOSFETS1 and the switch tube MOSFETS2 form the first bridge arm of the inverter circuit, and the switch tube MOSFETS3 and the switch tube MOSFETS4 form the second bridge arm of the inverter circuit. The drain of the switch tube MOSFETS1 is connected to the switch tube S A3The source of the switch tube MOSFETS1 is connected to the drain of the switch tube MOSFETS2, and the source of the switch tube MOSFETS2 is connected to the DC input voltage U DC The source of the switching tube MOSFETS2 is connected to the source of the switching tube MOSFETS4, the drain of the switching tube MOSFETS4 is connected to the source of the switching tube MOSFETS3, and the drain of the switching tube MOSFETS3 is connected to the drain of the switching tube MOSFETS1.

[0060] The inverter circuit's switches are not connected to parallel resonant capacitors. This design eliminates the potential adverse effects of sudden discharge surges from the parallel resonant capacitors on the safety of the switches. In other words, the absence of parallel resonant capacitors in the switches further improves their safety, ensuring the long-term, safe operation of the wireless charging system in complex industrial environments.

[0061] The transmitter compensation network includes the transmitter side compensation inductor L P1 , transmitter side compensation capacitor C P1 and the transmitter side compensation capacitor C P ;

[0062] The source of the switch tube MOSFETS1 is connected to the emitter side compensation inductor L P1 One end of the transmitter side compensation inductor L P1 The other end is connected to the transmitter side compensation capacitor C P1 One end of the transmitter side compensation capacitor C P1 The other end is connected to the drain of the switch tube MOSFETS4; the transmitter side compensation inductor L P1 The other end is connected to the transmitter side compensation capacitor C P One end of the transmitter side compensation capacitor C P The other end is used to connect an input connection end of the coupling mechanism, the transmitter side compensation capacitor C P1 The other end is used to connect to another input connection end of the coupling mechanism.

[0063] The coupling mechanism includes a transmitting side and a receiving side, and the transmitting side includes a transmitting coil L P , the receiving side includes a receiving coil L S ;

[0064] Transmitting coil L P The same-name end is connected to the transmitter side compensation capacitor C P The other end of the transmitting coil L P The opposite end is connected to the drain of the switch tube MOSFETS4;

[0065] Receiving coil L S The same-name terminal is used as a connection terminal of the receiving compensation network, and the receiving coil L SThe opposite end of the terminal serves as the other connection end of the receiving end compensation network.

[0066] Receiver compensation network Receiver side compensation capacitor C S , receiving side compensation inductor L S1 and the receiving side compensation capacitor C S1 ;

[0067] Receiving coil L S The same-name end is connected to the receiving side compensation capacitor C S One end of the receiving side compensation capacitor C S The other end is connected to the receiving side compensation capacitor C S1 One end of the receiving side compensation capacitor C S1 The other end is connected to the receiving coil L S The opposite end of the receiving side compensation capacitor C S The other end is connected to the receiving side compensation inductor L S1 One end of the receiving side, the compensation inductor L S1 The other end is used as a connection end of the rectifier circuit, and the receiving side compensation capacitor C S1 The other end serves as the other connection end of the rectifier circuit.

[0068] The rectifier circuit includes switch tubes MOSFETS5, MOSFETS6, MOSFETS7 and MOSFETS8. The switch tubes MOSFETS5 and MOSFETS6 form a first bridge arm of the rectifier circuit, and the switch tubes MOSFETS7 and MOSFETS8 form a second bridge arm of the rectifier circuit. The receiving side compensation inductor L S1 The other end is connected to the source of the switch tube MOSFETS5, the drain of the switch tube MOSFETS5 is connected to the drain of the switch tube MOSFETS7, and the source of the switch tube MOSFETS7 is connected to the receiving side compensation capacitor C S1 The other end is connected to the drain of the switching tube MOSFETS8, the source of the switching tube MOSFETS8 is connected to the source of the switching tube MOSFETS6, and the drain of the switching tube MOSFETS6 is connected to the source of the switching tube MOSFETS5.

[0069] The second auxiliary network also includes a switch tube S B3 ;

[0070] Switching tube S B1 The source of the switch tube MOSFETS7 is connected to the drain of the switch tube S B3 The source of the switch tube S B1 The drain of the switch tube S B2 The drain of the switch tube S B2 The source connection inductor L B One end of the inductor LB The other end is connected to the switch tube S B3 The drain and capacitor C B1 One end of the capacitor C B1 The other end is connected to the source of the switch tube MOSFETS8;

[0071] Switching tube S B2 The source of the diode D B2 The cathode of diode D B2 The anode connection capacitance C B2 One end and diode D B1 The cathode of the capacitor C B2 The other end of the inductor L B The other end of the diode D B1 The anode is connected to the source of the switching tube MOSFETS8;

[0072] Switching tube S B1 The drain of the output electrolytic capacitor C O2 One end and charging voltage U BAT The positive electrode of the output electrolytic capacitor C O2 The other end is connected to the source of the switch tube MOSFETS8 and the charging voltage U BAT of the negative electrode.

[0073] The bidirectional wireless power transmission system described in this embodiment can achieve efficient charging and discharging in the full load range.

[0074] In this embodiment, the diode D A1 (D B1 )、Capacitor C A1 (C B1 )、Capacitor C A2 (C B2 ) and the switch tube S A3 (S B3 ) is designed to be connected in parallel with the bridge arm, with the help of capacitor C A1 (C B1 ) and capacitor C A2 (C B2 ) discharge, so that the DC bus voltage drops to zero.

[0075] By DC input voltage U DC (U BAT )、Switching tube S A2 (S B2 )、Inductor L A (L B )、Switching tube S A3 (S B3 ) and the circuit formed by the bridge arm is to make the DC input voltage U DC(U BAT ) has enough energy stored to L A (L B ) among.

[0076] By DC input voltage U DC (U BAT )、Switching tube S A2 (S B2 )、Inductor L A (L B ) and capacitor C A1 (C B1 ) is to pass the inductor L A (L B ) and capacitor C A1 (C B1 ) causes the DC bus voltage to rise from zero.

[0077] By the inductor L A (L B )、Capacitor C A2 (C B2 ) and diode D A2 (D B2 ) is to utilize the inductance L A and capacitor C A2 (C B2 ) between the resonance, the inductor L A (L B ) is transferred to capacitor C A2 (C B2 ).

[0078] By DC input voltage U DC (U BAT )、Switching tube S A1 (S B1 )、Switching tube S A3 (S B3 )、Inductor L A (L B )、Diode D A2 (D B2 ) and diode D A1 (D B1 ) is to connect the inductor L A (L B ) is fed back to the DC input voltage U DC (U BAT ).

[0079] Switching tube S A1 (S B1 ) and the switch tube S A2 (S B2) are designed to trigger the reduction and increase of the DC bus voltage respectively.

[0080] Switching tube S A3 (S B3 ) is to ensure that the capacitor C A1 (C B1 ) will not be directly connected in parallel with the bridge arm. Otherwise, the control interference may cause the bridge arm to be in a direct-through state, so that the capacitor C A1 (C B1 ) Sudden discharge generates surge current, which will damage the switching tube in the inverter circuit or rectifier circuit.

[0081] The bidirectional wireless power transmission system relies solely on energy transfer between resonant capacitors during DC bus voltage drops, rather than in a resonant state. Therefore, during this period, only the input current of the transmitter or receiver flows through the auxiliary network. This helps reduce losses in the auxiliary network, particularly under light load conditions, and effectively improves efficiency.

[0082] Specific implementation method 2: Figures 1 to 11 As shown, the present invention also provides a wide range soft switching control method for a bidirectional wireless power transmission system, which is used to control the switching of the bidirectional wireless power transmission system described in the first embodiment, including:

[0083] The soft switching commutation principle of the charging mode and the discharging mode of the bidirectional wireless power transmission system is the same; the soft switching control of the charging mode in one switching cycle includes nine soft switching commutation modes:

[0084] Mode 1 [0~t0]: Make the switch S A1 On, DC input voltage U DC Through the switch tube S A1 and the switch MOSFETS1 to supply energy to the first auxiliary network until the capacitor C A1 Voltage u across both ends CA1 and capacitor C A2 Voltage u across both ends CA2 The value of U DC , reaching the moment t0; at the moment t0, the switch tube S A1 Turn off and make the switch tube S A3 conduction;

[0085] Mode 2 [t0~t1]: At time t0, the capacitor C A1 and capacitor C A2 For switch tube S A1 Voltage u across both ends SA1 The rising rate of the switch tube S A1 Achieve zero voltage shutdown; at this time, the switch tube S A3 Voltage u across both endsSA3 is zero until the switch tube S A3 Turn on, switch tube S A3 Achieve zero voltage turn-on; then, the capacitor C A1 and capacitor C A2 Start discharging, capacitor C A1 Voltage u across both ends CA1 and capacitor C A2 Voltage u across both ends CA2 It decreases linearly to zero and reaches time t1;

[0086] Mode 3 [t1~t2]: At t1, the DC bus voltage has dropped to zero, and the switch tubes MOSFETS1, MOSFETS2 and MOSFETS4 perform zero-loss switching. S 3 is in the off state until the switching is completed and reaches time t2; the duration of [t1~t2] is not less than the dead zone working time of the system;

[0087] Mode 4 [t2~t3]: At time t2, the switch tube S A2 conduction, inductance L A Limit switch tube S A2 The current i during conduction SA2 , so that the switch tube S A2 Achieve zero current conduction; inductor L A The voltage across the two ends u LA For U DC , flows through the inductor L A The current i LA Increase linearly until the current i LA rises to a value equal to the current flowing through the transmitter-side compensation inductor L P1 The current I0 reaches the moment t3;

[0088] Mode 5 [t3~t4]: At time t3, the inductor L A and capacitor C A1 Resonance, in charging state, flowing through inductor L A The current i LA and capacitor C A1 Voltage u across both ends CA1 increases nonlinearly until the capacitance C A1 Voltage u across both ends CA1 Rise to U DC , reaching time t4;

[0089] Mode 6 [t4~t5]: At time t4, the inductor L A and capacitor C A1 Resonance ends; inductance L A , switch tube S A1 The body diode and switch tube SA2 and switch tube S A3 A circulation loop is formed, reaching time t5;

[0090] Mode 7 [t5~t6]: At t5, the switch S A2 Turn off; capacitor C A2 Limits the switch S A2 The voltage change rate at both ends of the switch at the time of shutdown makes the switch tube S A2 Achieve zero voltage shutdown; inductor L A and capacitor C A2 Resonance, inductance L A Release electrical energy, capacitor C A2 In charging mode, current flows through the inductor L A The current i LA Nonlinearity decreases, capacitance C A2 Voltage u across both ends CA2 The nonlinearity increases until the switch tube S A2 The voltage across the two ends is equal to U DC , reaching time t6;

[0091] Mode 8 [t6~t7]: At time t6, the inductor L A and capacitor C A2 Resonance ends, inductor L A The voltage across the terminals remains at U DC , inductance L A Release electrical energy and flow through inductor L A The current i LA Linearly decreasing, current flows through the inductor L at time t6 A The current i LA Greater than the current flowing through the transmitter side compensation inductor L P1 The current I0 begins to flow through the switch tube S A1 until the current flows through the inductor L A The current i LA Linearly decreases to equal the current flowing through the transmitter side compensation inductor L P1 The current I0 of the switch tube S A1 The body diode freewheeling ends and reaches the moment t7;

[0092] Mode 9 [t7~t8]: At t7, the inductor L A The voltage across the two ends remains U DC , flows through the inductor L A The current i LA It continues to decrease linearly until it reaches zero, and at time t8, a switching cycle ends.

[0093] In this embodiment, the duty cycle of the switches in the auxiliary network and the associated delay time can be set to constant values. Therefore, there is no need to detect the instantaneous value of the transmitter or receiver input current to adjust the associated delay time in real time. This eliminates interference that may be caused by transmitter or receiver current detection, significantly improving the reliability of the bidirectional wireless power transmission system.

[0094] Simulation verification: The following simulation model is built by software for verification and analysis. The main simulation parameters selected are shown in Table 1:

[0095] Table 1 Main simulation parameters

[0096] parameter Numerical parameter Numerical <![CDATA[DC input voltage U DC > 100V <![CDATA[Receiving-side compensation inductor L S1 > 22.8µH <![CDATA[System operating frequency f S > 100kHz <![CDATA[Receiving-side compensation capacitor C S1 > 154.0nF <![CDATA[Transmitting coil L P > 37.0µH <![CDATA[Receiving-side compensation capacitor C S > 210.8nF <![CDATA[Receiving coil L S > 39.4µH <![CDATA[Inductor L A (Inductor L B )]]> 2µH <![CDATA[Mutual inductance M between the transmitting coil and the receiving coil PS > 12.75µH <![CDATA[Capacitor C A1 (Capacitor C B1 )]]> 15nF <![CDATA[Emitter-side compensation inductor L P1 > 21.4µH <![CDATA[Capacitor C A2 (Capacitor C B2 )]]> 22nF

[0097] from Figure 12 It can be found that the switch tube S A1 Achieved zero voltage turn-on and zero voltage turn-off. Figure 13 It can be found that the switch tube S A2 The zero current turn-on and zero voltage turn-off are realized. Figure 14 It can be seen that the switch tube S A3 Zero switching loss is achieved. Figure 15 It can be seen that u CA1 、u CA2 and i LA The variation trend of is basically consistent with the theoretical analysis, which verifies the effect of the present invention.

[0098] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in conjunction with other described embodiments.

Claims

1. A two-way wireless power transmission system, characterized in that: Including DC input voltage U DC , inverter circuit, first auxiliary network, input electrolytic capacitor C O1 , transmitter compensation network, coupling mechanism, receiver compensation network, rectifier circuit, second auxiliary network, output electrolytic capacitor C O2 and charging voltage U BAT ; At the DC input voltage U DC An input electrolytic capacitor C is set in parallel between the inverter circuit O1 and the first auxiliary network; the inverter circuit is connected to the coupling mechanism via the transmitter compensation network, and the coupling mechanism is then connected to the rectifier circuit via the receiver compensation network; in the rectifier circuit and the charging voltage U BAT The second auxiliary network is set in parallel between the output electrolytic capacitor C O2 ; The first auxiliary network is supplied with a DC input voltage U DC The circuit structure of the inverter circuit side and the second auxiliary network are connected by the charging voltage U BAT The circuit structure of the rectifier circuit side is the same as that of the rectifier circuit side; the first auxiliary network includes a switch tube S A1 , switch tube S A2 、Inductor L A , capacitor C A1 , capacitor C A2 , diode D A1 and diode D A2 , using the switch tube S A1 and switch tube S A2 For inductance L A , capacitor C A1 and capacitor C A2 The resonant state is controlled to provide the necessary conditions for realizing full range soft switching of the inverter switch tube. A1 and diode D A2 Realize the energy feedback function; the second auxiliary network includes the switch tube S B1 , switch tube S B2 、Inductor L B , capacitor C B1 , capacitor C B2 , diode D B1 and diode D B2 , using the switch tube S B1 and switch tube S B2 For inductance L B , capacitor C B1 and capacitor C B2 The resonant state is controlled to provide the necessary conditions for achieving full range soft switching of the rectifier switch tube. B1 and diode D B2 Realize energy feedback function; The first auxiliary network also includes a switch tube S A3 ; DC input voltage U DC The positive terminal of the input electrolytic capacitor C O1 One end, DC input voltage U DC The negative terminal of the input electrolytic capacitor C O1 The other end; DC input voltage U DC The cathode of the diode D is connected A1 The anode and capacitor C A1 One end of the diode D A1 The cathode of the diode D is connected A2 The anode and capacitor C A2 One end of the diode D A2 The cathode connection inductance L A One end of the inductor L A The other end of the capacitor C A1 The other end and capacitor C A2 the other end; Diode D A2 The cathode of the switch tube S is connected A2 The source of the switch tube S A2 The drain of the switch tube S A1 The drain of the switch tube S A1 The source of the switch tube S A3 The source of the switch tube S A3 The drain connection inductance L A the other end.

2. The two-way wireless power transmission system according to claim 1, characterized in that: The inverter circuit includes switch tubes MOSFETS1, MOSFETS2, MOSFETS3 and MOSFETS4. The drain of switch tube MOSFETS1 is connected to the drain of switch tube S A3 The source of the switch tube MOSFETS1 is connected to the drain of the switch tube MOSFETS2, and the source of the switch tube MOSFETS2 is connected to the DC input voltage U DC The source of the switching tube MOSFETS2 is connected to the source of the switching tube MOSFETS4, the drain of the switching tube MOSFETS4 is connected to the source of the switching tube MOSFETS3, and the drain of the switching tube MOSFETS3 is connected to the drain of the switching tube MOSFETS1.

3. The two-way wireless power transmission system according to claim 2, characterized in that: The transmitter compensation network includes the transmitter side compensation inductor L P1 , transmitter side compensation capacitor C P1 and the transmitter side compensation capacitor C P ; The source of the switch tube MOSFETS1 is connected to the emitter side compensation inductor L P1 One end of the transmitter side compensation inductor L P1 The other end is connected to the transmitter side compensation capacitor C P1 One end of the transmitter side compensation capacitor C P1 The other end is connected to the drain of the switch tube MOSFETS4; Transmitter side compensation inductor L P1 The other end is connected to the transmitter side compensation capacitor C P One end of the transmitter side compensation capacitor C P The other end is used to connect an input connection end of the coupling mechanism, the transmitter side compensation capacitor C P1 The other end is used to connect to another input connection end of the coupling mechanism.

4. The two-way wireless power transmission system according to claim 3, characterized in that: The coupling mechanism includes a transmitting side and a receiving side, and the transmitting side includes a transmitting coil L P , the receiving side includes a receiving coil L S ; Transmitting coil L P The same-name end is connected to the transmitter side compensation capacitor C P The other end of the transmitting coil L P The opposite end is connected to the drain of the switch tube MOSFETS4; Receiving coil L S The same-name terminal is used as a connection terminal of the receiving compensation network, and the receiving coil L S The opposite end of the terminal serves as the other connection end of the receiving end compensation network.

5. The two-way wireless power transmission system according to claim 4, characterized in that: Receiver compensation network Receiver side compensation capacitor C S , receiving side compensation inductor L S1 and the receiving side compensation capacitor C S1 ; Receiving coil L S The same-name end is connected to the receiving side compensation capacitor C S One end of the receiving side compensation capacitor C S The other end is connected to the receiving side compensation capacitor C S1 One end of the receiving side compensation capacitor C S1 The other end is connected to the receiving coil L S The opposite end of the receiving side compensation capacitor C S The other end is connected to the receiving side compensation inductor L S1 One end of the receiving side, the compensation inductor L S1 The other end is used as a connection end of the rectifier circuit, and the receiving side compensation capacitor C S1 The other end serves as the other connection end of the rectifier circuit.

6. The two-way wireless power transmission system according to claim 5, characterized in that: The rectifier circuit includes switch tubes MOSFETS5, MOSFETS6, MOSFETS7 and MOSFETS8, and the receiving side compensation inductor L S1 The other end is connected to the source of the switch tube MOSFETS5, the drain of the switch tube MOSFETS5 is connected to the drain of the switch tube MOSFETS7, and the source of the switch tube MOSFETS7 is connected to the receiving side compensation capacitor C S1 The other end is connected to the drain of the switching tube MOSFETS8, the source of the switching tube MOSFETS8 is connected to the source of the switching tube MOSFETS6, and the drain of the switching tube MOSFETS6 is connected to the source of the switching tube MOSFETS5.

7. The two-way wireless power transmission system according to claim 6, characterized in that: The second auxiliary network also includes a switch tube S B3 ; Switching tube S B1 The source of the switch tube MOSFETS7 is connected to the drain of the switch tube S B3 The source of the switch tube S B1 The drain of the switch tube S B2 The drain of the switch tube S B2 The source connection inductor L B One end of the inductor L B The other end is connected to the switch tube S B3 The drain and capacitor C B1 One end of the capacitor C B1 The other end is connected to the source of the switch tube MOSFETS8; Switching tube S B2 The source of the diode D B2 The cathode of diode D B2 The anode connection capacitance C B2 One end and diode D B1 The cathode of the capacitor C B2 The other end of the inductor L B The other end of the diode D B1 The anode is connected to the source of the switching tube MOSFETS8; Switching tube S B1 The drain of the output electrolytic capacitor C O2 One end and charging voltage U BAT The positive electrode of the output electrolytic capacitor C O2 The other end is connected to the source of the switch tube MOSFETS8 and the charging voltage U BAT of the negative electrode.

8. A wide range soft switching control method for a bidirectional wireless power transmission system, used for performing switching control on the bidirectional wireless power transmission system according to claim 7, characterized in that: include: The soft switching commutation principle of the charging mode and the discharging mode of the bidirectional wireless power transmission system is the same; the soft switching control of the charging mode in one switching cycle includes nine soft switching commutation modes: Mode 1 [0~t0]: Make the switch S A1 On, DC input voltage U DC Through the switch tube S A1 and the switch MOSFETS1 to supply energy to the first auxiliary network until the capacitor C A1 Voltage u across both ends CA1 and capacitor C A2 Voltage u across both ends CA2 The value of U DC , reaching the moment t0; at the moment t0, the switch tube S A1 Turn off and make the switch tube S A3 conduction; Mode 2 [t0~t1]: At time t0, the capacitor C A1 and capacitor C A2 For switch tube S A1 Voltage u across both ends SA1 The rising rate of the switch tube S A1 Achieve zero voltage shutdown; at this time, the switch tube S A3 Voltage u across both ends SA3 is zero, the switch tube S A3 Achieve zero voltage turn-on; then, the capacitor C A1 and capacitor C A2 Start discharging, capacitor C A1 Voltage u across both ends CA1 and capacitor C A2 Voltage u across both ends CA2 It decreases linearly to zero and reaches time t1; Mode 3 [t1-t2]: At time t1, the DC bus voltage has dropped to zero, and the switch tubes MOSFETS1, MOSFETS2, and MOSFETS4 perform zero-loss switching. The switch tube MOSFETS3 is in the off state until the switching is completed at time t2. The duration of [t1-t2] is not less than the dead-band working time of the system. Mode 4 [t2~t3]: At time t2, the switch tube S A2 conduction, inductance L A Limit switch tube S A2 The current i during conduction SA2 , so that the switch tube S A2 Achieve zero current conduction; inductor L A The voltage across the two ends u LA For U DC , flows through the inductor L A The current i LA Increase linearly until the current i LA rises to a value equal to the current flowing through the transmitter-side compensation inductor L P1 The current I0 reaches the moment t3; Mode 5 [t3~t4]: At time t3, the inductor L A and capacitor C A1 Resonance, in charging state, flowing through inductor L A The current i LA and capacitor C A1 Voltage u across both ends CA1 increases nonlinearly until the capacitance C A1 Voltage u across both ends CA1 Rise to U DC , reaching time t4; Mode 6 [t4~t5]: At time t4, the inductor L A and capacitor C A1 Resonance ends; inductance L A , switch tube S A1 The body diode and switch tube S A2 and switch tube S A3 A circulation loop is formed, reaching time t5; Mode 7 [t5~t6]: At t5, the switch S A2 Turn off; capacitor C A2 Limits the switch S A2 The voltage change rate at both ends of the switch at the time of shutdown makes the switch tube S A2 Achieve zero voltage shutdown; inductor L A and capacitor C A2 Resonance, inductance L A Release electrical energy, capacitor C A2 In charging mode, current flows through the inductor L A The current i LA Nonlinearity decreases, capacitance C A2 Voltage u across both ends CA2 The nonlinearity increases until the switch tube S A2 The voltage across the two ends is equal to U DC , reaching time t6; Mode 8 [t6~t7]: At time t6, the inductor L A and capacitor C A2 Resonance ends, inductor L A The voltage across the terminals remains at U DC , inductance L A Release electrical energy and flow through inductor L A The current i LA Linearly decreasing, current flows through the inductor L at time t6 A The current i LA Greater than the current flowing through the transmitter side compensation inductor L P1 The current I0 begins to flow through the switch tube S A1 until the current flows through the inductor L A The current i LA Linearly decreases to equal the current flowing through the transmitter side compensation inductor L P1 The current I0, the switch tube S A1 The body diode freewheeling ends and reaches the moment t7; Mode 9 [t7~t8]: At t7, the inductor L A The voltage across the two ends remains U DC , flows through the inductor L A The current i LA It continues to decrease linearly until it reaches zero, and at time t8, a switching cycle ends.

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