Soft switching high-frequency resonant conversion circuit

Abstract

The invention discloses a soft switching high-frequency resonant conversion circuit. Comprising a direct-current power supply, an inductor module, a switching tube module, a diode module, a resonant capacitor and an output filter capacitor, the specific connection relation is that the power supply module is connected with the inductor module through the switch tube module; the inductance module is connected with the output filtering module through the diode module; the resonant capacitor module is connected with the switch tube module and the inductor module. By adopting the non-bridge topological structure, the short circuit problem caused by simultaneous conduction of the switch tubes in the upper and lower bridge arm structures is avoided, so that dead time does not need to be set, the control logic is remarkably simplified, and the high-frequency bridge circuit is particularly suitable for being applied in a high-frequency scene.

Description

Technical Field

[0001] The present invention belongs to the field of power electronic power conversion, and more specifically, relates to a soft-switching high-frequency resonant conversion circuit. Background Art

[0002] High-frequency design is an effective way to improve the power density of power electronic converters. To overcome the increased switching losses associated with high-frequency operation, soft-switching techniques are often employed simultaneously. Among various soft-switching techniques, resonant soft switching is the most common. However, existing resonant converter circuits are generally based on half-bridge or full-bridge structures, such as series resonant circuits, parallel resonant circuits, series-parallel resonant circuits, and LLC resonant circuits. To prevent simultaneous conduction of the upper and lower switches in a half-bridge or full-bridge resonant circuit, a dead-time is added to the control signals of the upper and lower switches. For applications with very high switching frequencies, a dead-time that is too long can severely impact converter performance, while a dead-time that is too short can create the risk of shoot-through. Overall, while existing soft-switching techniques help reduce switching losses in power electronic converters, the dead-time setting still restricts the development of higher-frequency converters.

[0003] The prior art invention patent with publication number CN114865923B proposes a series-parallel ultra-high frequency DC conversion device, including a series-parallel ultra-high frequency DC converter and a co-phase driver. The series-parallel ultra-high frequency DC converter is equipped with two fully-controlled switches. The co-phase driver is used to collect the DC output voltage and generate two co-phase drive signals to control the synchronous on and off of the two fully-controlled switches. The first end of the co-phase driver is used as an output end to generate a drive control signal, which is connected to the first end of the series-parallel ultra-high frequency DC converter, indicating that the control signal of the co-phase driver is used to control the normal operation of the series-parallel ultra-high frequency DC converter. The second end of the co-phase driver is used as an input end to collect the DC output voltage, which is connected to the second end of the series-parallel ultra-high frequency DC converter, indicating that the co-phase driver collects the DC output voltage of the series-parallel ultra-high frequency DC converter. As an ultra-high frequency DC conversion device with a "bridge" or "half-bridge" structure, this solution still has a potential dead zone setting problem. Summary of the Invention

[0004] In order to overcome the problem in the prior art that the resonant conversion circuit is affected by the dead zone setting and is difficult to meet high-frequency applications, the present invention provides a soft-switching high-frequency resonant conversion circuit.

[0005] The primary purpose of the present invention is to solve the above technical problems, and the technical solutions of the present invention are as follows:

[0006] The first aspect of the present invention provides a soft-switching high-frequency resonant conversion circuit, comprising: a DC power supply, an inductor module, a switch tube module, a diode module, a resonant capacitor, and an output filter capacitor;

[0007] The switch tube module includes a first switch tube module and a second switch tube module. The first switch tube module includes a first fully-controlled switch, a first parallel diode, and a first parallel capacitor. The second switch tube module includes a second fully-controlled switch, a second parallel diode, and a second parallel capacitor. The first end of the first switch tube module and the first end of the second switch tube module are both connected to the first end of the DC power supply.

[0008] The inductor module includes a first inductor, a second inductor, and a coupled inductor. The coupled inductor includes a first winding and a second winding, and the two windings have the same number of turns and are wound on the same magnetic core. The first end of the first inductor is connected to the second end of the first switching tube module and the first end of the resonant capacitor. The first end of the second inductor is connected to the second end of the second switching tube module and the second end of the resonant capacitor. The first end of the first winding and the second end of the second winding of the coupled inductor are connected to the second end of the DC power supply and the first end of the output filter capacitor.

[0009] The diode module includes a first rectifier diode and a second rectifier diode, wherein the first end of the first rectifier diode is connected to the second end of the first inductor and the second end of the first winding of the coupled inductor at the same time, the first end of the second rectifier diode is connected to the second end of the second inductor and the first end of the second winding of the coupled inductor at the same time, and the second end of the first rectifier diode and the second end of the second rectifier diode are connected to the second end of the output filter capacitor at the same time;

[0010] The first end and the second end of the output filter capacitor serve as the first output end and the second output end of the soft-switching high-frequency resonant conversion circuit, respectively, and are connected to the two ends of the load, respectively;

[0011] The soft-switching high-frequency resonant conversion circuit controls energy transfer by turning on and off the first fully-controlled switch and the second fully-controlled switch, thereby adjusting the output voltage.

[0012] Preferably, both the first switch tube module and the second switch tube module are NMOS transistors;

[0013] When the first end and the second end of the DC power supply correspond to the negative electrode and the positive electrode of the DC power supply respectively, the first end and the second end of the first switching tube module and the second switching tube module correspond to the source and the drain of the NMOS transistor respectively, and the first end and the second end of the first rectifier diode and the second rectifier diode are the cathode and the anode respectively;

[0014] When the first end and the second end of the DC power supply correspond to the positive electrode and the negative electrode of the DC power supply respectively, the first end and the second end of the first switching tube module and the second switching tube module correspond to the drain and the source of the NMOS transistor respectively, and the first end and the second end of the first rectifier diode and the second rectifier diode are the anode and the cathode respectively.

[0015] Optionally, both the first switch tube module and the second switch tube module are PMOS transistors;

[0016] When the first end and the second end of the DC power supply correspond to the negative electrode and the positive electrode of the DC power supply respectively, the first end and the second end of the first switching tube module and the second switching tube module correspond to the drain and the source of the PMOS transistor respectively, and the first end and the second end of the first rectifier diode and the second rectifier diode are the cathode and the anode respectively;

[0017] When the first end and the second end of the DC power supply correspond to the positive electrode and the negative electrode of the DC power supply respectively, the first end and the second end of the first switching tube module and the second switching tube module correspond to the source and the drain of the PMOS transistor respectively, and the first end and the second end of the first rectifier diode and the second rectifier diode are the anode and the cathode respectively.

[0018] Furthermore, in the switch tube module, the first fully-controlled switch and the second fully-controlled switch are alternately turned on, and the on-duty ratio of both is 0.5.

[0019] Furthermore, the first inductor and the second inductor have the same inductance value.

[0020] Furthermore, the first parallel capacitor and the second parallel capacitor have the same capacitance value.

[0021] Furthermore, the resonant frequency of the conversion circuit is determined by the inductance values of the first inductor and the second inductor, the capacitance values of the first parallel capacitor and the second parallel capacitor, and the capacitance value of the resonant capacitor.

[0022] Furthermore, the switching frequencies of the first fully-controlled switch and the second fully-controlled switch are lower than the resonant frequency.

[0023] Furthermore, the first fully-controlled switch and the second fully-controlled switch are both turned on and off under zero voltage conditions, specifically:

[0024] When the first fully-controlled switch is turned off and the second fully-controlled switch is turned on, the first parallel capacitor, the resonant capacitor, and the first inductor form a resonant branch, so that the voltage of the first parallel capacitor gradually increases from 0 to a certain amplitude and then gradually decreases to 0. Subsequently, the first parallel diode is turned on to carry out freewheeling, so that the voltage of the first parallel capacitor remains at 0 until the first fully-controlled switch is turned on and the second fully-controlled switch is turned off;

[0025] When the second fully-controlled switch is turned off and the first fully-controlled switch is turned on, the second parallel capacitor, the resonant capacitor and the second inductor form a resonant branch, so that the voltage of the second parallel capacitor gradually increases from 0 to a certain amplitude and then gradually decreases to 0. Then the second parallel diode is turned on to continue the current, so that the voltage of the second parallel capacitor remains at 0 until the second fully-controlled switch is turned on and the first fully-controlled switch is turned off.

[0026] Furthermore, by changing the switching frequencies of the first fully-controlled switch and the second fully-controlled switch, the output voltage of the conversion circuit can be changed.

[0027] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0028] The soft-switching high-frequency resonant converter circuit proposed in this invention has the advantages of simple structure, high efficiency, and suitability for high-frequency operation. By adopting a non-bridge topology, it avoids the short-circuit problem caused by the simultaneous conduction of the switches in the upper and lower bridge arms. This eliminates the need for dead time settings, significantly simplifies the control logic, and is particularly suitable for high-frequency applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the purpose and technical solution of the present invention clearer, the present invention provides the following drawings and descriptions:

[0030] Figure 1 A soft-switching high-frequency resonant conversion circuit diagram provided by an embodiment of the present invention;

[0031] Figure 2 Another structural circuit diagram of a soft-switching high-frequency resonant conversion circuit provided by an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of changes in the operating state of a circuit provided by an embodiment of the present invention;

[0033] Figure 4 A simulation model diagram provided for an embodiment of the present invention;

[0034] Figure 5 A diagram of simulation waveform results provided by an embodiment of the present invention;

[0035] Figure 6 This is a simulated waveform diagram of the output voltage under different square wave control signal frequencies provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0038] Example 1:

[0039] The present invention provides a soft-switching high-frequency resonant conversion circuit for converting a DC power supply voltage Vin into a DC output voltage Vo and supplying the same to a load Ro. Figure 1 The figure shows a soft switching high frequency resonant conversion circuit diagram, as shown in Figure 2 Another structure of a soft-switching high-frequency resonant conversion circuit proposed in the present invention is shown.

[0040] The circuit diagram includes: DC power supply Vin, switch tube module, diode module, resonant capacitor Cr and output filter capacitor Co, and the load is represented by Ro;

[0041] The switch tube module includes a first switch tube module S1 and a second switch tube module S2. The first switch tube module S1 includes a first fully-controlled switch, a first parallel diode, and a first parallel capacitor. The second switch tube module S2 includes a second fully-controlled switch, a second parallel diode, and a second parallel capacitor. The first end of the first switch tube module S1 and the first end of the second switch tube module S2 are both connected to the first end of the DC power supply Vin.

[0042] The inductor module includes a first inductor Lr1, a second inductor Lr2, and a coupled inductor. The coupled inductor includes a first winding n1 and a second winding n2, both of which have the same number of turns and are wound on the same magnetic core. The first end of the first inductor Lr1 is connected to the second end of the first switching tube module S1 and the first end of the resonant capacitor Cr. The first end of the second inductor Lr2 is connected to the second end of the second switching tube module S2 and the second end of the resonant capacitor Cr. The first end of the first winding n1 and the second end of the second winding n2 of the coupled inductor are connected to the second end of the DC power supply Vin and the first end of the output filter capacitor Co.

[0043] The diode module includes a first rectifier diode D1 and a second rectifier diode D2, wherein the first end of the first rectifier diode D1 is connected to the second end of the first inductor Lr1 and the second end of the first winding n1 of the coupled inductor, the first end of the second rectifier diode D2 is connected to the second end of the second inductor Lr2 and the first end of the second winding n2 of the coupled inductor, and the second end of the first rectifier diode D1 and the second end of the second rectifier diode D2 are connected to the second end of the output filter capacitor Co.

[0044] The first end and the second end of the output filter capacitor Co serve as the first output end and the second output end of the soft-switching high-frequency resonant conversion circuit, respectively, and are connected to the two ends of the load, respectively;

[0045] The soft-switching high-frequency resonant conversion circuit controls energy transfer by turning on and off the first fully-controlled switch and the second fully-controlled switch, thereby adjusting the output voltage.

[0046] More specifically, if the first switch tube module S1 and the second switch tube module S2 are both NMOS transistors or both PMOS transistors, then:

[0047] like Figure 1 As shown, when the first and second ends of the DC power supply Vin correspond to the negative and positive electrodes of the DC power supply Vin, respectively: when S1 and S2 are both NMOS transistors, the first and second ends of the first switch tube module S1 and the second switch tube module S2 correspond to the source and drain of the NMOS transistor, respectively, and the first and second ends of the first rectifier diode D1 and the second rectifier diode D2 are the cathode and the anode, respectively; when S1 and S2 are both PMOS transistors, the first and second ends of the first switch tube module S1 and the second switch tube module S2 correspond to the drain and source of the NMOS transistor, respectively, and the first and second ends of the first rectifier diode D1 and the second rectifier diode D2 are the cathode and the anode, respectively;

[0048] like Figure 2 As shown, when the first end and the second end of the DC power supply Vin correspond to the positive and negative electrodes of the DC power supply Vin, respectively: when S1 and S2 are both NMOS transistors, the first end and the second end of the first switch tube module S1 and the second switch tube module S2 correspond to the drain and source of the NMOS transistor, respectively, and the first end and the second end of the first rectifier diode D1 and the second rectifier diode D2 are the anode and the cathode, respectively; when S1 and S2 are both PMOS transistors, the first end and the second end of the first switch tube module S1 and the second switch tube module S2 correspond to the source and the drain of the NMOS transistor, respectively, and the first end and the second end of the first rectifier diode D1 and the second rectifier diode D2 are the anode and the cathode, respectively.

[0049] More specifically, in the switch tube module, the first fully-controlled switch and the second fully-controlled switch are alternately turned on, and the on-duty ratio of both is 0.5.

[0050] More specifically, the first inductor Lr1 and the second inductor Lr2 have the same inductance value, that is, Lr1 = Lr2 = Lr.

[0051] More specifically, the first parallel capacitor and the second parallel capacitor have the same capacitance value, both Cp.

[0052] More specifically, the resonant frequency f of the conversion circuit r It is determined by the inductance values of the first inductor Lr1 and the second inductor Lr2, the capacitance values of the first parallel capacitor and the second parallel capacitor, and the capacitance value of the resonant capacitor Cr, that is,

[0053] More specifically, the switching frequencies f of the first fully-controlled switch and the second fully-controlled switch are S Below the resonant frequency f r , that is, f S <f r .

[0054] The change of the operating state of the present invention is as follows Figure 3 As shown in the figure, when the switch tube S1 is turned on and S2 is turned off, the resonant capacitor Cr and the parallel capacitor of S2 are connected in parallel and charged by the current iL2 of the inductor Lr2, so that their voltages increase from 0, so S2 is turned off at zero voltage; the current of the inductor Lr1 flows through the first winding n1 of the coupled inductor and induces the same current in the second winding n2, that is, i n2 =i n1 =i L1 ; Current i of inductor Lr2 L2 The sum of the current of the second winding of the coupled inductor i L2 +i n2 =i L2 +i L1 =i o , supplies power to the output capacitor Co and the load through the second rectifier diode D2; the current i of the inductor Lr1 L1 Rapidly drops to 0 and increases in the reverse direction; when the current i L1 The current i increases in the reverse direction to a value greater than the inductor Lr2. L2 After that, the current difference i L1 -i L2 The first rectifier diode D1 supplies power to the output capacitor Co and the load; the current i L2 Gradually decreases to 0 and then increases in the opposite direction. The parallel capacitance of the resonant capacitor Cr and S2 begins to discharge, causing their voltage to gradually decrease. When the voltage of the parallel capacitance of the resonant capacitor Cr and S2 drops to 0, the parallel diode of the switch tube S2 turns on and continues the current, so that the voltage of Cr and S2 remains at 0 until the switch tube S2 turns on and S1 turns off. Therefore, S2 is turned on at zero voltage.

[0055] When the switch S2 is turned on and S1 is turned off, the resonant capacitor Cr is connected in parallel with the parallel capacitor of S1 and is connected together by the current i of the inductor Lr1. L1 Charging makes their voltage increase from 0, so S1 is zero voltage off; the current of inductor Lr2 flows through the second winding n2 of the coupled inductor and induces the same current in the first winding n1, that is, in1 =i n2 =i L2 ; Current i of inductor Lr1 L1 The sum of the current of the first winding of the coupled inductor i L1 +i n1 =i L1 +i L2 =i o The first rectifier diode D1 supplies power to the output capacitor Co and the load; the current i L2 Rapidly drops to 0 and increases in the opposite direction; when the current i L2 The reverse current i increases to a value greater than the inductor Lr1. L1 After that, the current difference i L2 -i L1 The second rectifier diode D2 supplies power to the output capacitor Co and the load; the current i L1 Gradually decreases to 0 and then increases in the opposite direction. The parallel capacitance of the resonant capacitor Cr and S1 begins to discharge, causing their voltage to gradually decrease. When the voltage of the parallel capacitance of the resonant capacitor Cr and S1 drops to 0, the parallel diode of the switch tube S1 turns on to continue the current, so that the voltage of Cr and S1 remains at 0 until the switch tube S1 turns on and S2 turns off. Therefore, S1 is turned on at zero voltage.

[0056] In summary, the first fully-controlled switch S1 and the second fully-controlled switch S2 are both turned on and off under zero voltage conditions, specifically:

[0057] When the first fully-controlled switch S1 is turned off and the second fully-controlled switch S2 is turned on, the first parallel capacitor, the resonant capacitor Cr, and the first inductor Lr1 form a resonant branch, causing the voltage of the first parallel capacitor to gradually increase from 0 to a certain amplitude and then gradually decrease to 0. Subsequently, the first parallel diode is turned on to carry out freewheeling, so that the voltage of the first parallel capacitor remains at 0 until the first fully-controlled switch S1 is turned on and the second fully-controlled switch S2 is turned off. Therefore, S1 is turned on and off under zero voltage conditions;

[0058] When the second fully-controlled switch S2 is turned off and the first fully-controlled switch S1 is turned on, the second parallel capacitor, the resonant capacitor Cr, and the second inductor Lr2 form a resonant branch, so that the voltage of the second parallel capacitor gradually increases from 0 to a certain amplitude and then gradually decreases to 0. Subsequently, the second parallel diode is turned on to provide freewheeling current, so that the voltage of the second parallel capacitor remains at 0 until the second fully-controlled switch S2 is turned on and the first fully-controlled switch S1 is turned off. Therefore, S2 is turned on and off under zero voltage conditions.

[0059] More specifically, by changing the switching frequency f of the first fully-controlled switch S1 and the second fully-controlled switch S2 S, the output voltage Vo of the conversion circuit can be changed to adapt to the changes in the load Ro or the input voltage Vin of the power module, thereby achieving stable control of the output voltage,

[0060] When the switches S1 and S2 operate alternately at high frequency, the inductors Lr1 and Lr2, the resonant capacitor Cr, and the parallel capacitance of the switches S1 and S2 together form a resonant network. On the one hand, this provides zero-voltage switching conditions for the switches S1 and S2. On the other hand, it provides energy to the output capacitor Co and the load through the coupled inductor and rectifier diodes D1 and D2, so that stable DC power is obtained at both ends of the load.

[0061] Like traditional resonant converters (LLC, LCC, series resonance, etc.), the output voltage can be adjusted by changing the switching frequency of the switches S1 and S2 in the proposed conversion circuit, thereby maintaining the output voltage stable when the load or input voltage changes.

[0062] In the simulation software PSIM, the following Figure 4 In the simulation model shown in the figure, in this embodiment, the resonant capacitor Cr is 0.1nF, the parallel capacitors of the switch tubes are all 0.1nF, the resonant inductor L1 = L2 = 0.4uH, the coupled inductor turns ratio is 1:1, the output filter capacitor Co is 1uF, and the load Ro is 10Ω.

[0063] When the square wave control signal frequency is 10MHz, the simulation waveform results are as follows: Figure 5 As shown. It can be seen that the switch S1 is directly controlled by the square wave control signal. Before S1 is turned on, its voltage V S1 After S1 turns off, its voltage gradually increases from 0, so S1 operates in a zero-voltage switching state. S2 is directly controlled by the inverse of the square-wave control signal, with no dead zone between it and S1's control signal. S2 also operates in a zero-voltage switching state. The output voltage Vo is stable at 71.6V, and the high-frequency ripple amplitude is less than 0.1V.

[0064] In addition, if Figure 6 Figure 2 shows the simulated waveforms of the output voltage Vo when the square wave control signal frequency is 8 MHz, 10 MHz, and 12 MHz. It can be seen that the output voltage Vo can be controlled by changing the frequency of the square wave control signal.

[0065] The soft-switching high-frequency resonant converter circuit proposed in this invention has the advantages of simple structure, high efficiency, and suitability for high-frequency operation. By adopting a non-bridge topology, it avoids the short-circuit problem caused by the simultaneous conduction of the switches in the upper and lower bridge arms. This eliminates the need for dead time settings, significantly simplifies the control logic, and is particularly suitable for high-frequency applications.

[0066] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A soft-switching high-frequency resonant conversion circuit, characterized in that: include: DC power supply, inductor module, switch tube module, diode module, resonant capacitor and output filter capacitor; The switch tube module includes a first switch tube module and a second switch tube module. The first switch tube module includes a first fully-controlled switch, a first parallel diode, and a first parallel capacitor. The second switch tube module includes a second fully-controlled switch, a second parallel diode, and a second parallel capacitor. The first end of the first switch tube module and the first end of the second switch tube module are both connected to the first end of the DC power supply. The inductor module includes a first inductor, a second inductor, and a coupled inductor. The coupled inductor includes a first winding and a second winding, and the two windings have the same number of turns and are wound on the same magnetic core. The first end of the first inductor is connected to the second end of the first switching tube module and the first end of the resonant capacitor. The first end of the second inductor is connected to the second end of the second switching tube module and the second end of the resonant capacitor. The first end of the first winding and the second end of the second winding of the coupled inductor are connected to the second end of the DC power supply and the first end of the output filter capacitor. The diode module includes a first rectifier diode and a second rectifier diode, wherein the first end of the first rectifier diode is connected to the second end of the first inductor and the second end of the first winding of the coupled inductor at the same time, the first end of the second rectifier diode is connected to the second end of the second inductor and the first end of the second winding of the coupled inductor at the same time, and the second end of the first rectifier diode and the second end of the second rectifier diode are connected to the second end of the output filter capacitor at the same time; The first end and the second end of the output filter capacitor serve as the first output end and the second output end of the soft-switching high-frequency resonant conversion circuit, respectively, and are connected to the two ends of the load, respectively; The soft-switching high-frequency resonant conversion circuit controls energy transfer by turning on and off the first fully-controlled switch and the second fully-controlled switch, thereby adjusting the output voltage.

2. A soft-switching high-frequency resonant conversion circuit according to claim 1, characterized in that: The first switch tube module and the second switch tube module are both NMOS transistors; When the first end and the second end of the DC power supply correspond to the negative electrode and the positive electrode of the DC power supply respectively, the first end and the second end of the first switching tube module and the second switching tube module correspond to the source and the drain of the NMOS transistor respectively, and the first end and the second end of the first rectifier diode and the second rectifier diode are the cathode and the anode respectively; When the first end and the second end of the DC power supply correspond to the positive electrode and the negative electrode of the DC power supply respectively, the first end and the second end of the first switching tube module and the second switching tube module correspond to the drain and the source of the NMOS transistor respectively, and the first end and the second end of the first rectifier diode and the second rectifier diode are the anode and the cathode respectively.

3. The soft-switching high-frequency resonant conversion circuit according to claim 1, characterized in that: The first switch tube module and the second switch tube module are both PMOS transistors; When the first end and the second end of the DC power supply correspond to the negative electrode and the positive electrode of the DC power supply respectively, the first end and the second end of the first switching tube module and the second switching tube module correspond to the drain and the source of the PMOS transistor respectively, and the first end and the second end of the first rectifier diode and the second rectifier diode are the cathode and the anode respectively; When the first end and the second end of the DC power supply correspond to the positive electrode and the negative electrode of the DC power supply respectively, the first end and the second end of the first switching tube module and the second switching tube module correspond to the source and the drain of the PMOS transistor respectively, and the first end and the second end of the first rectifier diode and the second rectifier diode are the anode and the cathode respectively.

4. The soft-switching high-frequency resonant conversion circuit according to claim 1, characterized in that: In the switch tube module, the first fully-controlled switch and the second fully-controlled switch are alternately turned on, and the duty cycle of both is 0.

5.

5. The soft-switching high-frequency resonant conversion circuit according to claim 4, characterized in that: The first inductor and the second inductor have the same inductance value.

6. The soft-switching high-frequency resonant conversion circuit according to claim 5, characterized in that: The first parallel capacitor and the second parallel capacitor have the same capacitance value.

7. The soft-switching high-frequency resonant conversion circuit according to claim 6, characterized in that: The resonant frequency of the conversion circuit is determined by the inductance values of the first inductor and the second inductor, the capacitance values of the first parallel capacitor and the second parallel capacitor, and the capacitance value of the resonant capacitor.

8. The soft-switching high-frequency resonant conversion circuit according to claim 7, characterized in that: The switching frequencies of the first fully-controlled switch and the second fully-controlled switch are lower than the resonant frequency.

9. The soft-switching high-frequency resonant conversion circuit according to claim 7, characterized in that: The first fully-controlled switch and the second fully-controlled switch are both turned on and off under zero voltage conditions, specifically: When the first fully-controlled switch is turned off and the second fully-controlled switch is turned on, the first parallel capacitor, the resonant capacitor, and the first inductor form a resonant branch, so that the voltage of the first parallel capacitor gradually increases from 0 to a certain amplitude and then gradually decreases to 0. Subsequently, the first parallel diode is turned on to carry out freewheeling, so that the voltage of the first parallel capacitor remains at 0 until the first fully-controlled switch is turned on and the second fully-controlled switch is turned off; When the second fully-controlled switch is turned off and the first fully-controlled switch is turned on, the second parallel capacitor, the resonant capacitor and the second inductor form a resonant branch, so that the voltage of the second parallel capacitor gradually increases from 0 to a certain amplitude and then gradually decreases to 0. Then the second parallel diode is turned on to continue the current, so that the voltage of the second parallel capacitor remains at 0 until the second fully-controlled switch is turned on and the first fully-controlled switch is turned off.

10. The soft-switching high-frequency resonant conversion circuit according to claim 9, characterized in that: By changing the switching frequencies of the first fully-controlled switch and the second fully-controlled switch, the output voltage of the conversion circuit can be changed.

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