Six-switching-tube gain broadening type LLC resonant converter topological structure based on coupling inductor and control method of six-switching-tube gain broadening type LLC resonant converter topological structure
Through the topology of the six-switch tube gain widening LLC resonant converter based on coupled inductor, two working mode switching and modular coupling inductor are adopted, the problems of large switching losses and switching tube losses in the process of high frequency and miniaturization of DC/DC converters are solved, and high-efficiency energy transfer and voltage gain range are achieved.
Patent Information
- Application Number
- CN202510599409.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-11
- Publication Date
- 2025-07-08
AI Technical Summary
In the high frequency and miniaturization process, existing DC/DC converters have problems such as increasing switching losses and increasing secondary diode reverse recovery losses. In the high frequency and miniaturization process, common resonant converter topology has a large switching losses in switch tubes in wide input voltage and wide gain occasions.
The six-switch tube gain widening LLC resonant converter topology based on coupled inductor is adopted. Through switching between two working modes, the converter voltage gain range is widened, and the modulated coupling inductor is used to narrow the modulation frequency range.
It improves the energy transfer efficiency of the converter, reduces switching losses, expands the voltage gain range of the converter, and adapts to wide input voltage and load changes.
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Figure CN120281190A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of converters, in particular to a six-switch gain-boosted LLC resonant converter topology based on a coupled inductor and a control method therefor. Background Art
[0002] In recent years, with the development of technology, the control frequency of DC converters has tended to be high-frequency, which has also greatly promoted the miniaturization of passive components such as transformers, inductors, and capacitors in DC / DC converters. However, the development trends of high-frequency and miniaturization will also bring many disadvantages at the same time: as the switching frequency increases, the switching losses of the converter under hard-switching technology increase; the reverse recovery losses of the secondary diodes increase. To solve the above problems, researchers have introduced soft-switching technology on the basis of active DC converters.
[0003] In DC / DC topologies, resonant converters are beneficial to the realization of soft-switching due to the resonance characteristics of their own passive components, so resonant converters have received more and more attention. After years of development of technology, a series of resonant converter topologies have been proposed. The most common resonant converter topologies are mainly the following: 1. Series Resonant Converter (SRC); 2. Parallel Resonant Converter (PRC); 3. LCC Resonant Converter; 4. LLC Resonant Converter.
[0004] When the operating frequency of the Series Resonant Converter (SRC) is greater than the resonant frequency, the switching tubes of the SRC can achieve ZVS; when the operating frequency of the SRC is less than the resonant frequency, the switching tubes of the SRC cannot achieve ZVS. Therefore, the operating frequency of the SRC should be greater than the resonant frequency. The problems of the SRC are: when the converter is in a light load condition, it is difficult to control the converter to output a stable voltage; when the converter is in a high input condition, the high circulating energy in the resonant cavity will cause the switching losses to increase sharply.
[0005] Similarly, when the operating frequency of the Parallel Resonant Converter (PRC) is greater than the resonant frequency of the resonant cavity, ZVS can be achieved. The problems of the PRC are: when the converter load is close to the no-load condition, its input impedance increases and the circulating energy increases, resulting in a sharp increase in switching losses; when the converter is in a high input condition, there will be both high circulating energy and high turn-off current in the resonant cavity.
[0006] The LCC resonant converter is actually a combination of SRC and PRC. Similar to the above, when the operating frequency is greater than the resonant frequency of the resonant cavity, the converter can achieve ZVS. Compared with the SRC topology, when the LCC is under light load, the control frequency adjustment range of the converter is larger; compared with the PRC topology, under high-voltage input, the circulating energy and turn-off current of the resonant circuit are smaller. The problems it has are: it is not suitable for occasions with wide input voltage, and when the converter requires wide gain, the switching loss of the switching tube is large. Summary of the Invention
[0007] In view of this, the purpose of the present invention is to provide a six-switch gain-boosting LLC resonant converter topology structure based on a coupled inductor and its control method to improve the energy transfer efficiency of the converter.
[0008] To achieve the above purpose, the present invention adopts the following technical solution: A six-switch gain-boosting LLC resonant converter topology structure based on a coupled inductor, including a first port and a second port; the first port serves as the power supply end, and the second port correspondingly serves as the load end; it also includes a first switching loop and a second switching loop. The first switching loop includes switching tubes S1, S2, S3, S4, S5, and S6; the second switching loop includes diodes Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, and an output voltage stabilizing capacitor C0; an inductor L is provided in the first port r1 and inductor L r2 The inductor L r1 and inductor L r2 are mutually coupled to form a pair of coupled inductors. Two resonant capacitors, namely resonant capacitor C r1 and resonant capacitor C r2 , are provided in the first port. It also includes a transformer T1 and a transformer T2. The exciting inductances of the transformer T1 and the transformer T2 are respectively exciting inductance L m1 and exciting inductance L m2 .
[0009] In a preferred embodiment, the switching tubes S1, S2, and S3 are connected in series as the first group of switching tubes, and the switching tubes S4, S5, and S6 are connected in series as the second group of switching tubes. The first group of switching tubes and the second group of switching tubes are connected in parallel as a pair of bridge arms; the sources of the switching tubes S1 and S4 are connected together and connected to the positive pole of the DC source. The drains of the switching tubes S1 and S4 are respectively connected to the sources of the switching tubes S2 and S5. The drains of the switching tubes S2 and S5 are respectively connected to the sources of the switching tubes S3 and S6. The drains of the switching tubes S3 and S6 are connected together and connected to the negative pole of the DC source.
[0010] In a preferred embodiment, the excitation inductor L m1 is connected in parallel with the transformer T1, and the excitation inductor L m2 is connected in parallel with the transformer T2; the drain of the switching transistor S1 is connected to one end of the resonant capacitor C r1 , the other end of the resonant capacitor C r1 is connected to the excitation inductor L m1 and the transformer T1, the other end of the excitation inductor L m1 and the transformer T1 is then connected to the resonant inductor L r1 , the other end of the resonant inductor L r1 is then connected to the source of the switching transistor S5; the drain of the switching transistor S2 is connected to one end of the resonant inductor L r2 , the other end of the resonant inductor L r2 is connected to the excitation inductor L m2 and the transformer T2, the other end of the excitation inductor L m2 and the transformer T2 is then connected to the resonant capacitor C r2 , the other end of the resonant capacitor C r2 is then connected to the source of the switching transistor S6.
[0011] In a preferred embodiment, the diodes Q1, Q2, Q3 and Q4 are the first group of diodes, and the diodes Q5, Q6, Q7, Q8 are the second group of diodes; wherein, the input ends of the diodes Q1 and Q2 are respectively connected to the output ends of the diodes Q3 and Q4, the input ends of the diodes Q3 and Q4 are respectively connected to the output ends of the diodes Q5 and Q6, the input ends of the diodes Q5 and Q6 are respectively connected to the output ends of the diodes Q7 and Q8, the output ends of the diodes Q1 and Q2 are connected together and connected to one end of the filter capacitor C1, the other end of the filter capacitor C1 is connected to the input ends of the diodes Q3 and Q4, at the same time, the input ends of the diodes Q3 and Q4 are connected to one end of the filter capacitor C2, the input ends of the diodes Q7 and Q8 are connected together and connected to the other end of the filter capacitor C2, both ends of the filter capacitor C1 and the filter capacitor C2 are then connected in parallel with the voltage stabilizing capacitor C0, both ends of the voltage stabilizing capacitor C0 are then connected in parallel with the load, at the same time, the input end of the diode Q1 and the output end of the diode Q4 are connected to the secondary side of the transformer T1, the input end of the diode Q5 and the output end of the diode Q8 are connected to the secondary side of the transformer T2, so that the input end and the output end form a whole.
[0012] The present invention also provides a control method for a six-switch gain-boosted LLC resonant converter topology based on coupled inductors, adopting the six-switch gain-boosted LLC resonant converter topology based on coupled inductors as described above;
[0013] The first circuit state of the first operating mode, i.e., t0 - t1: At the moment t0, the switching transistors S2, S4, and S6 are turned off, and the switching transistors S1, S3, and S5 are turned on with zero voltage; at this time, the input voltages v a1b1 and v a2b2 of the two resonant cavities are both half of the power supply voltage V in / 2. The sum of the output voltages v c1d1 and v c2d2 of the transformer T1 and the transformer T2 is greater than the load voltage V0, and the diodes Q1, Q4, Q6, and Q7 are turned on. The primary side of the circuit transfers energy to the secondary side through the resonant cavities;
[0014] The second circuit state of the first operating mode, i.e., t1 - t2: At the moment t1, the current i Lr1 = i Lm1 , and i Lr2 = i Lm2 . The switching transistors S1, S3, and S5 continue to be turned on, but the current flowing through the transformer becomes 0. The diodes Q1, Q4, Q5, and Q8 are turned off with zero current, and the primary side no longer transfers energy to the secondary side. The load is powered by the output filter capacitor;
[0015] The third circuit state of the first operating mode, i.e., t2 - t3: This time period is the dead time. At the moment t2, S1, S3, and S5 are turned off, and the resonant current charges the parasitic capacitances of S1, S3, and S5 and discharges the parasitic capacitances of S2, S4, and S6. At the moment t3, the switching transistors S2, S4, and S6 are turned on, and this stage ends.
[0016] The present invention also provides a control method for a six-switch gain-boosted LLC resonant converter topology based on a coupled inductor, which adopts the six-switch gain-boosted LLC resonant converter topology based on a coupled inductor described above;
[0017] The first circuit state of the second operating mode, i.e., t0 - t1: At the moment t0, the switching transistors S3 and S4 are turned off, and the switching transistors S1 and S6 are turned on with zero voltage; at this time, the input voltages of the two resonant cavities are both the power supply voltage V in . The sum of the output voltages of the transformer T1 and the transformer T2 is greater than the load voltage V O , and the diodes Q1, Q4, Q5, and Q8 are turned on. The primary side of the circuit transfers energy to the secondary side through the resonant cavities;
[0018] The second circuit state of the second operating mode, i.e., t1 - t2: At the moment t1, the current i Lr1 = i Lm1 , iLr2 = i Lm2 , the switching transistors S1 and S6 are continuously conducting, but the current flowing through the transformer becomes 0, the diodes Q1, Q4, Q5, and Q8 are turned off with zero current, and no energy is transferred from the primary side to the secondary side. The load is powered by the output filter capacitor;
[0019] The third circuit state of the second operating mode, i.e., t2 - t3: This time period is the dead time. At t2, the switching transistors S1 and S6 are turned off with zero voltage, and the resonant current charges the parasitic capacitances of the switching transistors S1 and S6 and discharges the parasitic capacitances of the switching transistors S3 and S4. At t3, the switching transistors S3 and S4 are turned on, and this stage ends.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] 1) The six-switch gain-boosted LLC resonant converter based on a coupled inductor has two operating modes, and the voltage gain range of the converter can be broadened by switching the modes.
[0022] 2) The six-switch gain-boosted LLC resonant converter based on a coupled inductor uses a modifiable coupled inductor, and the inductor value is different in different modes, reducing the modulation frequency range. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 is a schematic diagram of the topology of the six-switch gain-boosted LLC resonant converter based on a coupled inductor according to a preferred embodiment of the present invention;
[0024] Figure 2 is a schematic diagram of the main operating waveforms of the first operating mode of the six-switch gain-boosted LLC resonant converter based on a coupled inductor according to a preferred embodiment of the present invention;
[0025] Figure 3 is a schematic diagram of the circuit state 1 of the first operating mode of the six-switch gain-boosted LLC resonant converter based on a coupled inductor according to a preferred embodiment of the present invention;
[0026] Figure 4 is a schematic diagram of the circuit state 2 of the first operating mode of the six-switch gain-boosted LLC resonant converter based on a coupled inductor according to a preferred embodiment of the present invention;
[0027] Figure 5 is a schematic diagram of the circuit state 3 of the first operating mode of the six-switch gain-boosted LLC resonant converter based on a coupled inductor according to a preferred embodiment of the present invention;
[0028] Figure 6Schematic diagram of the main waveforms of the second operating mode of the six-switch gain-boosted LLC resonant converter based on coupled inductors according to the preferred embodiment of the present invention;
[0029] Figure 7 Schematic diagram of circuit state 1 of the second operating mode of the six-switch gain-boosted LLC resonant converter based on coupled inductors according to the preferred embodiment of the present invention;
[0030] Figure 8 Schematic diagram of circuit state 2 of the second operating mode of the six-switch gain-boosted LLC resonant converter based on coupled inductors according to the preferred embodiment of the present invention;
[0031] Figure 9 Schematic diagram of circuit state 3 of the second operating mode of the six-switch gain-boosted LLC resonant converter based on coupled inductors according to the preferred embodiment of the present invention. Detailed implementation manners
[0032] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.
[0033] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.
[0034] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present application; as used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0035] The present invention discloses a topology structure and a control method of a six-switch gain-boosted LLC resonant converter based on coupled inductors, including a main circuit topology and a control method for the circuit. The topology structure of the six-switch gain-boosted LLC resonant converter based on coupled inductors is as Figure 1 shown.
[0036] As shown in the figure, the main circuit of the converter includes a first port, a second port, a pair of mutually coupled resonant inductors, two resonant capacitors, two transformers, and two switching circuits. The first port serves as the power supply terminal, and the second port correspondingly serves as the load terminal. Switch tubes S1, S2, S3, S4, S5, and S6 form the first switching circuit. Diodes Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, and the output voltage stabilizing capacitor C0 form the second switching circuit. L within the first port of the converter r1 and L r2 are mutually coupled to form a pair of coupled inductors. The two resonant capacitors within the first port of the converter are respectively C r1 and C r2 . The exciting inductances of the two transformers T1 and T2 of the converter are respectively L m1 and the exciting inductance L m2 .
[0037] In the connection relationship of each component in the six-switch tube gain-boosted LLC resonant converter topology based on coupled inductors: The input end consists of a DC source, six switch tubes, two resonant capacitors, two exciting inductors, and a pair of mutually coupled resonant inductors. The six switch tubes are divided into two groups with three in series in each group. Among them, switch tubes S1, S2, and S3 are in series in one group, and switch tubes S4, S5, and S6 are in series in the other group. The two groups of switch tubes are then connected in parallel to form a pair of bridge arms. The sources of switch tubes S1 and S4 are connected together and connected to the positive pole of the DC source. The drains of switch tubes S1 and S4 are respectively connected to the sources of switch tubes S2 and S5. The drains of switch tubes S2 and S5 are respectively connected to the sources of switch tubes S3 and S6. The drains of switch tubes S3 and S6 are connected together and connected to the negative pole of the DC source; among them, the exciting inductance L m1 is in parallel with transformer T1, and the exciting inductance L m2 is in parallel with transformer T2; the drain of switch tube S1 is connected to one end of the resonant capacitor C r1 . The other end of the resonant capacitor C r1 is connected to the exciting inductance L m1 and transformer T1. The other ends of the exciting inductance L m1 and transformer T1 are then connected to the resonant inductor L r1 . The other end of the resonant inductor L r1 is then connected to the source of switch tube S5; the drain of switch tube S2 is connected to one end of the resonant inductor L r2 . The other end of the resonant inductor L r2 is connected to the exciting inductance L m2 and transformer T2. The exciting inductance Lm2 and the other end of transformer T2 is further connected to resonant capacitor C r2 in series, and the other end of resonant capacitor C r2 is further connected to the source electrode of switching transistor S6; the above description is the connection manner of each device within the input port of the converter; the output end of the converter is composed of eight diodes, three capacitors and one resistor. The eight diodes are divided into two groups to form two pairs of rectifier bridges. Diode Q1, diode Q2, diode Q3 and diode Q4 are the first group, and diode Q5, diode Q6, diode Q7 and diode Q8 are the second group. Among them, the input ends of diode Q1 and diode Q2 are respectively connected to the output ends of diode Q3 and diode Q4, the input ends of diode Q3 and diode Q4 are respectively connected to the output ends of diode Q5 and diode Q6, the input ends of diode Q5 and diode Q6 are respectively connected to the output ends of diode Q7 and diode Q8. The output ends of diode Q1 and diode Q2 are connected together and connected to one end of filter capacitor C1, the other end of filter capacitor C1 is connected to the input ends of diode Q3 and diode Q4. At the same time, the input ends of diode Q3 and diode Q4 are connected to one end of filter capacitor C2, the input ends of diode Q7 and diode Q8 are connected together and connected to the other end of filter capacitor C2. The two ends of filter capacitor C1 and filter capacitor C2 are further connected in parallel with voltage stabilizing capacitor C0, and a load is further connected in parallel at both ends of voltage stabilizing capacitor C0. At the same time, the input end of diode Q1 and the output end of diode Q4 are connected to the secondary side of transformer T1, and the input end of diode Q5 and the output end of diode Q8 are connected to the secondary side of transformer T2, so that the input end and the output end form an integral body.
[0038] By adjusting the working state of the switching transistors, the converter has two working modes. In the first working mode, the working waveform of the converter is as shown in Figure 2 , and in the second working mode, the working waveform of the converter is as shown in Figure 2 . The two working modes are described in detail as follows:
[0039] Working mode one, circuit state 1 [t0 - t1]: Corresponding to Figure 3 , at time t0, switching transistors S2, S4 and S6 are turned off, and switching transistors S1, S3 and S5 are turned on with zero voltage. At this time, the input voltages v a1b1 , v a2b2 of the two resonant cavities are both half of the power supply voltage V in / 2. The sum of the output voltages v c1d1 , v c2d2 of the two transformers is greater than the load voltage V0. Diodes Q1, Q4, Q6 and Q7 are turned on, and energy is transferred from the primary side of the circuit to the secondary side through the resonant cavity.
[0040] Working mode 1 circuit state 2 [t1-t2]: corresponding Figure 4 At time t1, the current i Lr1 =i Lm1 ,i Lr2 =i Lm2 , switch tube S1, switch tube S3 and switch tube S5 are continuously turned on, but the current flowing through the transformer becomes 0, diode Q1, diode Q4, diode Q5 and diode Q8 are turned off with zero current, the primary side no longer transfers energy to the secondary side, and the load is powered by the output filter capacitor.
[0041] Working mode 1 circuit state 3 [t2-t3]: corresponding Figure 5 , this time period is the dead time. At time t2, the switch tubes S1, S3 and S5 are turned off, and the resonant current charges the parasitic capacitance of the switch tubes S1, S3 and S5, and discharges the parasitic capacitance of the switch tubes S2, S4 and S6. At time t3, the switch tubes S2, S4 and S6 are turned on, and this stage ends.
[0042] The above is the working process of the converter in the positive half cycle in the first working mode. Through the above analysis, it can be seen that the primary side of transformer T1 and transformer T2 is equivalent to being connected in series to V in This modulation method can control the transformer primary voltage amplitude to V in / 2, by changing the switching frequency of the primary switch tube, different voltage values can be output on the secondary side of the transformer. The working process in the negative half cycle is similar to the above process and will not be repeated here.
[0043] The working waveform of the converter in the positive half cycle of the second working mode is as follows: Figure 6 As shown, each working mode is described in detail as follows:
[0044] In the second working mode, the switch tube S2 and the switch tube S5 remain normally open, and the switch tube S2 and the switch tube S5 are not described again in the following analysis.
[0045] Working mode 2 circuit state 1[t0-t1]: corresponding Figure 7 At time t0, switch tubes S3 and S4 are turned off, and switch tubes S1 and S6 are turned on with zero voltage. At this time, the input voltages of the two resonant cavities are Both are power supply voltage V in , the two transformer output voltages The sum is greater than the load voltage V O , diode Q1, diode Q4, diode Q5 and diode Q8 are turned on, and the primary side of the circuit transfers energy to the secondary side through the resonant cavity.
[0046] Working mode 2 circuit state 2[t1-t2]: correspondingFigure 8 At time t1, the current is i Lr1 = i Lm1 , i Lr2 = i Lm2 , the switching transistors S1 and S6 are continuously conducting, but the current flowing through the transformer becomes 0. The diodes Q1, Q4, Q5, and Q8 turn off with zero current. The primary side no longer transfers energy to the secondary side, and the load is powered by the output filter capacitor.
[0047] Circuit state 3 [t2 - t3] of operating mode 2: Corresponding to Figure 9 , this time period is the dead time. At time t2, the switching transistors S1 and S6 turn off with zero voltage. The resonant current charges the parasitic capacitors of the switching transistors S1 and S6 and discharges the parasitic capacitors of the switching transistors S3 and S4. At time t3, the switching transistors S3 and S4 are turned on, and this stage ends.
[0048] The above is the working process of the positive half - cycle of the converter in the first operating mode. Through the above analysis, it can be seen that the primary sides of the transformers T1 and T2 are equivalent to being connected in parallel across V in Both ends, and this modulation method can control the amplitude of the primary - side voltage of the transformer to be V in . By changing the switching frequency of the primary - side switching transistors, different voltage values can be achieved at the secondary side of the transformer. The working process in the negative half - cycle is similar to the above process and will not be elaborated here.
[0049] Under the conditions of an input voltage of 250V - 450V and an output voltage of 800V, a 1000W converter prototype was built. MOSFETs are used as the switching devices for the two switching circuits. The driving signals of the main circuit are generated by the TI digital signal processor TMS320F280049, and then after isolation and amplification by the driving circuit, the driving voltage is provided for the switching transistors of the main circuit. Under these experimental conditions, the six - switching - transistor gain - broadened LLC resonant converter based on coupled inductors can operate normally in closed - loop under its modulation method. The converter prototype can operate normally under different input voltages and different loads.
[0050] The above - mentioned specific description further details the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above - mentioned is only a specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.
Claims
1. A six-switch gain-boosted LLC resonant converter topology based on coupled inductors, characterized in that, It includes a first port and a second port; the first port serves as the power supply terminal, and the second port correspondingly serves as the load terminal; it further includes a first switching circuit and a second switching circuit. The first switching circuit includes switching transistors S1, S2, S3, S4, S5, and S6; the second switching circuit includes diodes Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, and an output voltage stabilizing capacitor C0; an inductor L is provided in the first port r1 and the inductor L r2 The inductor L r1 and the inductor L r2 are mutually coupled to form a pair of coupled inductors. Two resonant capacitors, namely resonant capacitor C r1 and resonant capacitor C r2 , are provided in the first port. It further includes transformers T1 and T2. The exciting inductances of the transformers T1 and T2 are respectively exciting inductance L m1 and exciting inductance L m2 .
2. A six-switch gain-boosted LLC resonant converter topology based on coupled inductors according to claim 1, characterized in that, The switching transistors S1, S2, and S3 are connected in series to form the first group of switching transistors, and the switching transistors S4, S5, and S6 are connected in series to form the second group of switching transistors. The first group of switching transistors and the second group of switching transistors are connected in parallel to form a pair of bridge arms. The sources of the switching transistors S1 and S4 are connected together and connected to the positive pole of the DC source. The drains of the switching transistors S1 and S4 are respectively connected to the sources of the switching transistors S2 and S5. The drains of the switching transistors S2 and S5 are respectively connected to the sources of the switching transistors S3 and S6. The drains of the switching transistors S3 and S6 are connected together and connected to the negative pole of the DC source.
3. A six-switch gain-boosted LLC resonant converter topology based on a coupled inductor according to claim 1, characterized in that, The exciting inductance L m1 is connected in parallel with the transformer T1, and the exciting inductance L m2 is connected in parallel with the transformer T2; the drain of the switching transistor S1 is connected to one end of the resonant capacitor C r1 , the other end of the resonant capacitor C r1 is connected to the exciting inductance L m1 and the transformer T1. The other end of the exciting inductance L m1 and the transformer T1 is then connected to the resonant inductance L r1 , and the other end of the resonant inductance L r1 is then connected to the source of the switching transistor S5; the drain of the switching transistor S2 is connected to one end of the resonant inductance L r2 , the other end of the resonant inductance L r2 is connected to the exciting inductance L m2 and the transformer T2. The other end of the exciting inductance L m2 and the transformer T2 is then connected to the resonant capacitor C r2 , and the other end of the resonant capacitor C r2 is then connected to the source of the switching transistor S6.
4. A six-switch gain-boosted LLC resonant converter topology based on coupled inductors according to claim 1, characterized in that, The diodes Q1, Q2, Q3, and Q4 are the first group of diodes, and the diodes Q5, Q6, Q7, and Q8 are the second group of diodes. Among them, the input terminals of the diodes Q1 and Q2 are respectively connected to the output terminals of the diodes Q3 and Q4. The input terminals of the diodes Q3 and Q4 are respectively connected to the output terminals of the diodes Q5 and Q6. The input terminals of the diodes Q5 and Q6 are respectively connected to the output terminals of the diodes Q7 and Q8. The output terminals of the diodes Q1 and Q2 are connected together and connected to one end of the filter capacitor C1. The other end of the filter capacitor C1 is connected to the input terminals of the diodes Q3 and Q4. At the same time, the input terminals of the diodes Q3 and Q4 are connected to one end of the filter capacitor C2. The input terminals of the diodes Q7 and Q8 are connected together and connected to the other end of the filter capacitor C2. The two ends of the filter capacitor C1 and the filter capacitor C2 are then connected in parallel with the voltage stabilizing capacitor C0. The two ends of the voltage stabilizing capacitor C0 are then connected in parallel with the load. At the same time, the input terminal of the diode Q1 and the output terminal of the diode Q4 are connected to the secondary side of the transformer T1. The input terminal of the diode Q5 and the output terminal of the diode Q8 are connected to the secondary side of the transformer T2, so that the input terminal and the output terminal form a whole.
5. A control method for a six-switch gain-boosted LLC resonant converter topology based on coupled inductors, characterized in that, Adopt a six-switch gain-boosted LLC resonant converter topology structure based on coupled inductance described in any one of the above claims 1-4; The first circuit state of the first operating mode, i.e., t0 - t1: At the moment of t0, the switching transistors S2, S4, and S6 are turned off, and the switching transistors S1, S3, and S5 are turned on with zero voltage; at this time, the input voltages v a1b1 and v a2b2 of the two resonant cavities are both half of the power supply voltage V in / 2, and the sum of the output voltages v c1d1 and v c2d2 of the transformer T1 and the transformer T2 is greater than the load voltage V0, and the diodes Q1, Q4, Q6, and Q7 are turned on, and the primary side of the circuit transfers energy to the secondary side through the resonant cavity; The second circuit state of the first operating mode, namely t1 - t2: At time t1, the current i Lr1 = i Lm1 , i Lr2 = i Lm2 , the switching transistors S1, S3, and S5 continue to conduct, but the current flowing through the transformer becomes 0, the diodes Q1, Q4, Q5, and Q8 turn off with zero current, the primary side no longer transfers energy to the secondary side, and the load is powered by the output filter capacitor; The third circuit state of the first operating mode, i.e., t2 - t3: This time period is the dead time. At the moment t2, S1, S3, and S5 are turned off, and the resonant current charges the parasitic capacitors of S1, S3, and S5 and discharges the parasitic capacitors of S2, S4, and S6. At the moment t3, the switching transistors S2, S4, and S6 are turned on, and this stage ends.
6. A control method for a six-switch gain-boosted LLC resonant converter topology based on coupled inductors, characterized in that, Adopt a six-switch gain-boosted LLC resonant converter topology structure based on coupled inductance described in any one of the above claims 1-4; The first circuit state of the second operating mode, i.e., t0 - t1: At the moment of t0, the switching transistors S3 and S4 are turned off, and the switching transistors S1 and S6 are turned on with zero voltage; at this time, the input voltages of the two resonant cavities are both the power supply voltage V in , and the sum of the output voltages of the transformer T1 and the transformer T2 is greater than the load voltage V O , the diodes Q1, Q4, Q5, and Q8 are turned on, and the primary side of the circuit transfers energy to the secondary side through the resonant cavity; The second circuit state of the second operating mode, i.e., t1 - t2: At time t1, current i Lr1 = i Lm1 , i Lr2 = i Lm2 . Switching transistors S1 and S6 conduct continuously, but the current flowing through the transformer becomes 0. Diodes Q1, Q4, Q5, and Q8 turn off with zero current. The primary side no longer transfers energy to the secondary side, and the load is powered by the output filter capacitor. The third circuit state of the second operating mode, i.e., t2 - t3: This time period is the dead time. At the moment t2, the switching transistors S1 and S6 are turned off with zero voltage, and the resonant current charges the parasitic capacitors of the switching transistors S1 and S6 and discharges the parasitic capacitors of the switching transistors S3 and S4. At the moment t3, the switching transistors S3 and S4 are turned on, and this stage ends.