A wide range bidirectional soft switching voltage balancing circuit

Abstract

The present invention relates to a wide-range bidirectional soft-switching voltage-equalizing circuit, comprising: a transformer, first and second LLC resonant modules, a switch switching module, a first energy storage module, a second energy storage module, a first voltage-equalizing module, and a second voltage-equalizing module. The second LLC resonant module comprises a second resonant capacitor, a second resonant inductor, and a full-bridge rectifier unit; when the first and second ends of the switch switching module are connected, the third and fourth ends are connected, and the second and third ends are disconnected, the first energy storage module and the second energy storage module are connected in parallel; when the first and second ends of the switch switching module are disconnected, the third and fourth ends are disconnected, and the second and third ends are connected, the first energy storage module and the second energy storage module are connected in series. Soft switching can be realized on both sides of the circuit, and a wide range of voltage output can be realized at the same time, and only conventional devices need to be used, which has low cost, high conversion efficiency and power density.

Description

Technical Field

[0001] The present invention relates to the field of bidirectional power supply, and more specifically to a wide range bidirectional soft switch voltage balancing circuit. Background Art

[0002] Bidirectional power supplies are increasingly used in new energy systems, electric vehicle systems, outdoor power supplies, integrated charging and discharging machines, home storage systems, and other fields. Soft-switching resonant circuits are often used in the field of bidirectional power supplies because of their high efficiency and easy bidirectional conversion. However, due to the limited gain output of the soft-switching resonant circuit itself, it is difficult to adapt to a wide range of applications, especially those with a gain range greater than 2 times.

[0003] The prior art has proposed an implementation scheme of using fully-controlled switching devices to connect the output voltage in series to increase the output voltage. However, this requires significant changes to the bidirectional resonant circuit and requires the use of fully-controlled switching devices, which is not only costly and has low conversion efficiency but also has high requirements on the devices. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a wide-range bidirectional soft-switch voltage equalizing circuit that can achieve high-voltage wide-range output using conventional devices and has low cost, high conversion efficiency and power density in response to the above-mentioned defects of the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is: construct a wide range bidirectional soft switch voltage balancing circuit, including: a transformer, a first LLC resonance module arranged on the first side of the transformer, and a second LLC resonance module arranged on the second side of the transformer; the second LLC resonance module includes a second LC resonance unit and a full-bridge rectifier unit;

[0006] The wide range bidirectional soft switch voltage balancing circuit further comprises a switch switching module, a first energy storage module, a second energy storage module, a first voltage balancing module and a second voltage balancing module arranged on the second side of the transformer;

[0007] The first end of the second LC resonance unit is connected to the first end of the second side of the transformer, the second end is connected to the first end of the full-bridge rectifier unit, the third end is connected to the second end of the second side of the transformer, and the fourth end is connected to the second end of the full-bridge rectifier unit; the first energy storage module is connected between the third end and the fourth end of the full-bridge rectifier unit, and the second energy storage module is connected between the fifth end and the sixth end of the full-bridge rectifier unit;

[0008] The first end of the first voltage balancing module is connected to the third end of the full-bridge rectifier unit, the second end is connected to the fourth end of the full-bridge rectifier unit, and the third end is connected to the second end of the full-bridge rectifier unit; the first end of the second voltage balancing module is connected to the fifth end of the full-bridge rectifier unit, the second end is connected to the sixth end of the full-bridge rectifier unit, and the third end is connected to the first end of the full-bridge rectifier unit;

[0009] The first end of the switch switching module is connected to the third end of the full-bridge rectifier unit, the second end is connected to the fifth end of the full-bridge rectifier unit, the third end is connected to the fourth end of the full-bridge rectifier unit, and the fourth end is connected to the sixth end of the full-bridge rectifier unit; when the first end and the second end of the switch switching module are connected, the third end and the fourth end are connected, and the second end and the third end are disconnected, the first energy storage module and the second energy storage module are connected in parallel; when the first end and the second end of the switch switching module are disconnected, the third end and the fourth end are disconnected, and the second end and the third end are connected, the first energy storage module and the second energy storage module are connected in series;

[0010] When the direction of the wide-range bidirectional soft-switching voltage balancing circuit is from the first side of the transformer to the second side of the transformer, the first LLC resonant module realizes soft switching, and when the direction of the wide-range bidirectional soft-switching voltage balancing circuit is from the second side of the transformer to the first side of the transformer, the full-bridge rectifier unit realizes soft switching.

[0011] In the wide-range bidirectional soft switch voltage balancing circuit of the present invention, the switch switching module includes a first switch, a second switch and a third switch, the first switch is connected between the first end and the second end of the switch switching module, the second switch is connected between the third end and the fourth end of the switch switching module, and the third switch is connected between the second end and the third end of the switch switching module;

[0012] The first switch, the second switch and the third switch respectively include switch tubes or relay switches;

[0013] The first switch and the second switch are synchronized, and the first switch and the second switch are interlocked with the third switch.

[0014] In the wide-range bidirectional soft switch voltage balancing circuit described in the present invention, the switch switching module includes a double-pole switch, a double-pole switch controller, a single-pole switch and a single-pole switch controller;

[0015] The first moving contact of the double-pole switch is connected to the first end of the switch switching module, the second moving contact is connected to the fourth end of the switch switching module, the first static contact is connected to the second end of the switch switching module, and the second static contact is connected to the third end of the switch switching module; the double-pole switch controller controls the first moving contact and the second moving contact to simultaneously connect to the first static contact and the second static contact respectively or to disconnect from the first static contact and the second static contact;

[0016] The moving contact of the single-pole switch is connected to the third end of the switch switching module, and the static contact is connected to the second end of the switch switching module, and the single-pole switch controller controls the moving contact to connect with or disconnect from the static contact;

[0017] The double-pole switch and the single-pole switch are interlocked;

[0018] The double-pole switch includes a double-pole double-throw switch and a double-pole single-throw switch, and the single-pole switch includes a single-pole double-throw switch and a single-pole single-throw switch.

[0019] In the wide-range bidirectional soft switch voltage balancing circuit of the present invention, the switch switching module includes a first single-pole double-throw switch, a first switch controller, a second single-pole double-throw switch and a second switch controller;

[0020] The moving contact of the first single-pole double-throw switch is connected to the second end of the switch switching module, the normally open contact is connected to the first end of the switch switching module, and the normally closed contact is connected to the third end of the switch switching module; the moving contact of the second single-pole double-throw switch is also connected to the third end of the switch switching module, the normally closed contact is connected to the second end of the switch switching module, and the normally open contact is connected to the fourth end of the switch switching module;

[0021] The first switch controller and the second switch controller synchronously control the moving contact of the first single-pole double-throw switch and the moving contact of the second single-pole double-throw switch to connect to their corresponding normally open contacts or normally closed contacts.

[0022] In the wide-range bidirectional soft switch voltage-sharing circuit of the present invention, the switch switching module includes a double-pole double-throw switch and a switch controller;

[0023] The first moving contact of the double-pole double-throw switch is connected to the second end of the switch switching module, the second moving contact is connected to the third end of the switch switching module, the first normally open contact is connected to the first end of the switch switching module, the second normally open contact is connected to the fourth end of the switch switching module, the first normally closed contact is connected to the third end of the switch switching module, and the second normally closed contact is connected to the second end of the switch switching module;

[0024] The switch controller controls the first moving contact and the second moving contact of the double-pole double-throw switch to connect to their corresponding normally open contacts or normally closed contacts.

[0025] In the wide-range bidirectional soft-switch voltage balancing circuit described in the present invention, the first voltage balancing module includes a first diode, a second diode, a first voltage balancing inductor and a first voltage balancing capacitor, the cathode of the first diode is connected to the first end of the switch switching module and the third end of the full-bridge rectifier unit, and the anode is connected to the cathode of the second diode, the anode of the second diode is connected to the third end of the switch switching module and the fourth end of the full-bridge rectifier unit, and the cathode of the first diode is also connected to the second end of the full-bridge rectifier unit via the first voltage balancing inductor and the first voltage balancing capacitor in sequence.

[0026] In the wide-range bidirectional soft-switch balancing circuit described in the present invention, the second balancing module includes a third diode, a fourth diode, a second balancing inductor and a second balancing capacitor, the cathode of the third diode is connected to the second end of the switch switching module and the fifth end of the full-bridge rectifier unit, and the anode is connected to the cathode of the fourth diode, the anode of the fourth diode is connected to the fourth end of the switch switching module and the sixth end of the full-bridge rectifier unit, and the cathode of the third diode is also connected to the first end of the full-bridge rectifier unit via the second balancing inductor and the second balancing capacitor in sequence.

[0027] In the wide-range bidirectional soft-switch voltage balancing circuit described in the present invention, the full-bridge rectifier unit includes a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube, and the control ends of the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube respectively receive control signals, the first end of the fifth switch tube is connected to the first end of the full-bridge rectifier unit and the second end of the sixth switch tube, the second end of the fifth switch tube is connected to the third end of the full-bridge rectifier unit, the first end of the sixth switch tube is connected to the fourth end of the full-bridge rectifier unit, the first end of the seventh switch tube is connected to the second end of the full-bridge rectifier unit and the second end of the eighth switch tube, the second end of the seventh switch tube is connected to the fifth end of the full-bridge rectifier unit, and the first end of the eighth switch tube is connected to the sixth end of the full-bridge rectifier unit.

[0028] The wide-range bidirectional soft-switch voltage balancing circuit of the present invention further includes a filter capacitor connected between the third terminal and the sixth terminal of the full-bridge rectifier unit.

[0029] In the wide-range bidirectional soft-switching voltage-sharing circuit of the present invention, the second LC resonance unit includes a second resonance inductor and a second resonance capacitor;

[0030] The first end of the second resonant inductor is connected to the first end of the second side of the transformer, and the second end is connected to the first end of the full-bridge rectifier unit; the first end of the second resonant capacitor is connected to the second end of the second side of the transformer, and the second end is connected to the second end of the full-bridge rectifier unit; or

[0031] The second resonant inductor and the second resonant capacitor are connected in series between the first end of the second side of the transformer and the first end of the full-bridge rectifier unit; or

[0032] The second resonant inductor and the second resonant capacitor are connected in series between the second end of the second side of the transformer and the second end of the full-bridge rectifier unit; or

[0033] The first end of the second resonant capacitor is connected to the first end of the second side of the transformer, and the second end is connected to the first end of the full-bridge rectifier unit. The first end of the second resonant inductor is connected to the second end of the second side of the transformer, and the second end is connected to the second end of the full-bridge rectifier unit.

[0034] In the wide-range bidirectional soft-switching voltage balancing circuit described in the present invention, the first LLC resonant module includes a full-bridge LLC module or a half-bridge LLC module.

[0035] The wide-range bidirectional soft-switch voltage-equalizing circuit of the present invention can realize soft switching regardless of whether the voltage conversion is from the first side to the second side or from the second side to the first side, and can also realize a wide range of voltage output, and the entire circuit only needs to use conventional devices, so the cost is low, the conversion efficiency and power density are high. Furthermore, various types of switch devices can be used to implement the switch switching module, so the requirements of various application scenarios can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0037] Figure 1 It is a principle block diagram of a preferred embodiment of a wide range bidirectional soft switch voltage balancing circuit of the present invention;

[0038] Figure 2 is a circuit diagram of a preferred embodiment of a wide range bidirectional soft switch voltage balancing circuit of the present invention;

[0039] Figure 3 yes Figure 2 The first equivalent circuit diagram of the wide range bidirectional soft switching voltage balancing circuit shown;

[0040] Figure 4 yes Figure 2 The second equivalent circuit diagram of the wide range bidirectional soft switching voltage balancing circuit shown;

[0041] Figures 5A-5EDifferent construction modes of switch modules are shown;

[0042] Figure 6 is a circuit diagram of another preferred embodiment of a wide range bidirectional soft switch voltage balancing circuit of the present invention;

[0043] Figure 7 It is a circuit diagram of another preferred embodiment of a wide range bidirectional soft switch voltage equalizing circuit of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] Figure 1 1 is a principle block diagram of a preferred embodiment of a wide range bidirectional soft switch voltage balancing circuit of the present invention. Figure 1 As shown, the wide range bidirectional soft switch voltage balancing circuit includes: a transformer T1, a first LLC resonance module 100 arranged on the first side of the transformer T1, and a second LLC resonance module arranged on the second side of the transformer T1. The second LLC resonance module includes a second LC resonance unit 320 and a full-bridge rectifier unit 310. Figure 1 As shown, the wide range bidirectional soft switch voltage balancing circuit further includes a switch switching module 400, a first energy storage module 510, a second energy storage module 520, a first voltage balancing module 610 and a second voltage balancing module 620 arranged on the second side of the transformer T1.

[0046] like Figure 1As shown, the first end of the second LC resonance unit 320 is connected to the first end of the second side of the transformer T1, the second end is connected to the first end of the full-bridge rectifier unit 310, the third end is connected to the second end of the second side of the transformer T1, and the fourth end is connected to the second end of the full-bridge rectifier unit 310; the first energy storage module 510 is connected between the third end and the fourth end of the full-bridge rectifier unit 310, and the second energy storage module 520 is connected between the fifth end and the sixth end of the full-bridge rectifier unit 310. The first end of the first voltage balancing module 610 is connected to the third end of the full-bridge rectifier unit 310, the second end is connected to the fourth end of the full-bridge rectifier unit 310, and the third end is connected to the second end of the full-bridge rectifier unit 310; the first end of the second voltage balancing module 620 is connected to the fifth end of the full-bridge rectifier unit 310, the second end is connected to the sixth end of the full-bridge rectifier unit 310, and the third end is connected to the first end of the full-bridge rectifier unit 310. The first end of the switch switching module 400 is connected to the third end of the full-bridge rectifier unit 310, the second end is connected to the fifth end of the full-bridge rectifier unit 310, the third end is connected to the fourth end of the full-bridge rectifier unit 310, and the fourth end is connected to the sixth end of the full-bridge rectifier unit 310.

[0047] In a preferred embodiment of the present invention, the first LLC resonance module 100 may be in the form of a variety of resonance circuits, for example, a full-bridge LLC module or a half-bridge LLC module. The transformer T1 may be a single transformer or may include multiple series transformers. The second LLC resonance module is preferably a full-bridge LLC module, which includes a second LC resonance unit 320 composed of a resonant capacitor and a resonant inductor and a full-bridge rectifier unit 310. The resonant capacitor and the resonant inductor in the second LC resonance unit 320 may be connected in series, in parallel, or in various other ways, as long as they can achieve the resonance function.

[0048] For example, in Figure 1In the preferred embodiment shown, the second LC resonance unit includes a resonance capacitor Cr2 and a resonance inductor Lr2, the first end of the resonance inductor Lr2 is connected to the first end of the second side of the transformer T1, and the second end is connected to the first end of the full-bridge rectifier unit 310, the first end of the resonance capacitor Cr2 is connected to the second end of the second side of the transformer T1, and the second end is connected to the second end of the full-bridge rectifier unit 310. For another example, in a preferred embodiment of the present invention, the second LC resonance unit includes a second resonance inductor and a second resonance capacitor, and the second resonance inductor and the second resonance capacitor are connected in series between the first end of the second side of the transformer T1 and the first end of the full-bridge rectifier unit 310. For another example, in a preferred embodiment of the present invention, the second LC resonance unit includes a second resonance inductor and a second resonance capacitor, and the second resonance inductor and the second resonance capacitor are connected in series between the second end of the second side of the transformer T1 and the second end of the full-bridge rectifier unit 310. For another example, in a preferred embodiment of the present invention, the second LC resonance unit includes a second resonance inductor and a second resonance capacitor, the first end of the second resonance capacitor is connected to the first end of the second side of the transformer T1, and the second end is connected to the first end of the full-bridge rectifier unit 310, the first end of the second resonance inductor is connected to the second end of the second side of the transformer T1, and the second end is connected to the second end of the full-bridge rectifier unit 310. Of course, the second LC resonance unit 320 may also include multiple resonance capacitors and multiple resonance inductors, which all fall within the protection scope of the present invention.

[0049] The full-bridge rectifier unit 310 can be composed of a switch tube rectifier bridge. The first energy storage module 510 and the second energy storage module 520 preferably include at least one energy storage capacitor respectively. The first voltage equalizing module 610 and the second voltage equalizing module 620 can be composed of two series diodes and an LC unit connected to the voltage dividing point of the series diodes. The switch switching module 400 can be composed of a switch tube, a relay switch, or a combination thereof. It should be further explained that the resonant inductor Lr2 in the present invention includes not only the actually set inductance, but also the converted inductance. These all fall within the scope of protection of the present invention. In addition, in the present invention, a wide range means that its output voltage range can be the voltage on the resonant capacitor Co1 or Co2, or the sum of the voltages on the resonant capacitor Co1 or Co2.

[0050] When the first and second ends of the switch module 400 are disconnected, the third and fourth ends are disconnected, and the second and third ends are connected, the first energy storage module 510 and the second energy storage module 520 are connected in series, and a wide range LLC expansion and voltage balancing circuit is formed.

[0051] At this time, when the direction of the wide-range bidirectional soft-switching voltage-equalizing circuit is from the first side of the transformer T1 to the second side of the transformer T1, the transformer T1 and the switch tube of the first LLC resonant module 100 form a full-bridge switch circuit. The resonant unit of the first LLC resonant module 100 and the excitation inductance of the first side of the transformer T1 form an LLC resonant circuit. Therefore, the first side of the transformer can be regarded as a full-bridge LLC resonant circuit, and the switch tube of the first LLC resonant module 100 can easily achieve zero voltage switching (ZVS), that is, soft switching. At this time, on the second side of the transformer T1, the full-bridge rectifier unit 310 and the resonant capacitor Cr2 form a voltage-doubling half-wave rectifier circuit. The full-bridge rectifier unit 310 supplies power to the output through the resonant capacitor Cr2 and the output voltage-doubling capacitor and performs half-wave rectification.

[0052] When the direction of the wide-range bidirectional soft-switching voltage-equalizing circuit is from the second side of the transformer T1 to the first side of the transformer T1, the full-bridge rectifier unit 310 on the second side and the transformer T1 form a resonant circuit. The resonant inductor Lr2 and the excitation inductor on the second side of the transformer T1 form an LLC resonant circuit. At the same time, the resonant inductor shares the role of 1 / 2 of the output voltage Vo, so that the transformer T1 and the full-bridge rectifier unit 310 only bear 1 / 2Vo of the output voltage stress. Therefore, an LLC resonant circuit can also be formed on the second side of the transformer T1, and the switch tube of the full-bridge rectifier unit 310 can easily achieve zero voltage switching (ZVS), that is, soft switching. The switch tube of the first LLC resonant module 100 on the first side of the transformer T1 constitutes a bridge full-wave rectifier circuit.

[0053] The first end of the first voltage equalizing module 610 is connected to the third end of the full-bridge rectifier unit 310, the second end is connected to the fourth end of the full-bridge rectifier unit 310, and the third end is connected to the second end of the full-bridge rectifier unit 310. The first end of the second voltage equalizing module 620 is connected to the fifth end of the full-bridge rectifier unit 310, and the second end is connected to the sixth end of the full-bridge rectifier unit 310. In this way, the bias caused by the switch tube on the lagging bridge arm of the full-bridge rectifier unit 310 due to inconsistent delay time during driving, or differences in the turn-on delay time of the switch tube itself, or the influence of stray parameters in the circuit can be avoided, thereby making the voltage difference between the two energy storage modules controllable.

[0054] This design uses a half-wave rectification method with 2 times the voltage rectification in the forward direction (from the first side to the second side), and transmits 1 / 2 times the voltage to the transformer in the reverse direction. The voltage equalization module ensures that the voltage difference between the energy storage modules is very small, thereby ensuring that the full-bridge rectifier unit can operate at an output voltage of 1 / 2Vo. Therefore, a switch tube with a rated voltage of 1 / 2Vo_max can be selected. Since the ZVS zero-voltage soft opening of the switch tube is achieved in both the forward and reverse directions, the switching loss can be reduced, the switching efficiency can be improved, the heat dissipation requirement can be reduced, and the size of the module can be reduced.

[0055] When the first and second ends of the switch switching module 400 are conductive, the third and fourth ends are conductive, and the second and third ends are disconnected, the first energy storage module 510 and the second energy storage module 520 are connected in parallel, and a full-wave rectification LLC circuit is formed.

[0056] At this time, when the direction of the wide-range bidirectional soft-switching voltage-sharing circuit is from the first side of the transformer T1 to the second side of the transformer T1, the transformer T1 and the switch tube of the first LLC resonant module 100 form a full-bridge switch circuit. The resonance unit of the first LLC resonant module 100 and the excitation inductance of the first side of the transformer T1 form an LLC resonant circuit. Therefore, the first side of the transformer can be regarded as a full-bridge LLC resonant circuit, and the switch tube of the first LLC resonant module 100 can easily achieve zero voltage switching (ZVS), that is, soft switching. At this time, on the second side of the transformer T1, the full-bridge rectifier unit 310 constitutes a bridge full-wave rectifier circuit.

[0057] When the direction of the wide-range bidirectional soft-switching voltage-equalizing circuit is from the second side of the transformer T1 to the first side of the transformer T1, the full-bridge rectifier unit 310 on the second side and the transformer T1 form a resonant circuit. The resonant inductor Lr2 and the excitation inductor on the second side of the transformer T1 form an LLC resonant circuit. Therefore, it is also easy to form an LLC resonant circuit on the second side of the transformer T1, and the switch tube of the full-bridge rectifier unit 310 can easily achieve zero voltage switching (ZVS), that is, soft switching. At this time, on the first side of the transformer T1, the switch tube of the first LLC resonant module 100 can also form a bridge full-wave rectifier circuit.

[0058] Therefore, such a design, whether in forward or reverse direction, realizes the ZVS zero-voltage soft turn-on of the switch tube, which can reduce switching losses, improve switching efficiency, reduce heat dissipation requirements, and reduce the size of the module.

[0059] Figure 2 1 is a circuit diagram of a preferred embodiment of a wide range bidirectional soft switch voltage equalizing circuit of the present invention. Figure 1-2It can be seen that the wide range bidirectional soft switch voltage balancing circuit includes: a transformer T1, a first LLC resonant module 100 arranged on the first side of the transformer T1, and a second LLC resonant module arranged on the second side of the transformer T1, a switch switching module 400 arranged on the second side of the transformer T1, a first energy storage module 510, a second energy storage module 520, a first voltage balancing module 610 and a second voltage balancing module 620.

[0060] like Figure 2 As shown, the first LLC resonant module 100 includes a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, a resonant inductor Lr1, a resonant capacitor Cr1 and an energy storage capacitor Cin. The first LLC resonant module 100 is connected to the first side of the transformer T1, the excitation inductor of the transformer T1 is Lm, the excitation inductor of the first side (PRI side) is Lm1, and the excitation inductor of the second side (SEC side) is Lm2. The switch tube Q1, the switch tube Q2, the switch tube Q3, and the switch tube Q4 constitute a switch tube bridge circuit, and are respectively connected to the two ends of the first side of the transformer T1 through the resonant inductor Lr1 and the resonant capacitor Cr1. The control ends of the switch tube Q1, the switch tube Q2, the switch tube Q3, and the switch tube Q4 receive control signals respectively, and the control signals of the switch tube Q1 and the switch tube Q4 are the same, and the control signals of the switch tube Q2 and the switch tube Q3 are the same, that is, they are opened and closed at the same time.

[0061] The second LLC resonant module includes a resonant capacitor Cr2, a resonant inductor Lr2 and a full-bridge rectifier unit 310. The full-bridge rectifier unit 310 includes a full-bridge LLC module composed of a switch tube Q5, a switch tube Q6, a switch tube Q7 and a switch tube Q8. The resonant capacitor Cr2 is also used as a boost capacitor for voltage doubling rectification. The first energy storage module 510 and the second energy storage module 520 include energy storage capacitors Co1 and Co2, respectively. The first voltage equalizing module 610 includes a diode D1, a diode D2, a voltage equalizing inductor Lj1 and a voltage equalizing capacitor Cj1. The second voltage equalizing module 620 includes a diode D3, a diode D4, a voltage equalizing inductor Lj2 and a voltage equalizing capacitor Cj2. Figure 2 In the preferred embodiment shown, the switch switching module 400 includes a switch K1, a switch K2 and a switch K3. In this preferred embodiment, the switch K1, the switch K2 and the switch K3 respectively include a switch tube or a relay switch, which can be constructed using any suitable switch module as long as it can be controlled to be turned on or off.

[0062] like Figure 2As shown, the first end of the resonant inductor Lr2 is connected to the first end of the second side of the transformer T1, and the second end is connected to the first end of the switch tube Q5 and the second end of the switch tube Q6 (i.e., the first end of the full-bridge rectifier unit 310). The first end of the resonant capacitor Cr2 is connected to the second end of the second side of the transformer T1, and the second end is connected to the first end of the switch tube Q7 and the second end of the switch tube Q8 (i.e., the second end of the full-bridge rectifier unit 310). One end of the energy storage capacitor Co1 is connected to the second end of the switch tube Q5 (i.e., the third end of the full-bridge rectifier unit), and the other end is connected to the first end of the switch tube Q6 (i.e., the fourth end of the full-bridge rectifier unit). One end of the energy storage capacitor Co2 is connected to the second end of the switch tube Q7 (i.e., the fifth end of the full-bridge rectifier unit), and the other end is connected to the first end of the switch tube Q8 (i.e., the sixth end of the full-bridge rectifier unit). The control ends of the switch tubes Q5, Q6, Q7 and Q8 receive control signals respectively, and the control signals of the switch tubes Q5 and Q8 are the same, and the control signals of the switch tubes Q6 and Q7 are the same, that is, they are turned on and off at the same time.

[0063] The first end A of the switch switching module 400 is connected to the third end of the full-bridge rectifier unit 310, the second end B is connected to the fifth end of the full-bridge rectifier unit 310, the third end C is connected to the fourth end of the full-bridge rectifier unit 310, and the fourth end D is connected to the sixth end of the full-bridge rectifier unit 310. The switch K1 is connected between the first end A and the second end B of the switch switching module 400, the switch K2 is connected between the third end C and the fourth end D of the switch switching module 400, and the switch K3 is connected between the second end B and the third end C of the switch switching module 400. The switch K1 is synchronized with the switch K2, and the switch K1 and the switch K2 are interlocked with the switch K3.

[0064] like Figure 2 As shown, the cathode of the diode D1 is connected to the first end A of the switch switching module 400 and the third end of the full-bridge rectifier unit 310, and the anode is connected to the cathode of the diode D2. The anode of the diode D2 is connected to the third end C of the switch switching module 400 and the fourth end of the full-bridge rectifier unit 310. The cathode of the diode D1 is also connected to the second end of the full-bridge rectifier unit 310 via the voltage-sharing inductor Lj1 and the voltage-sharing capacitor Cj1 in sequence. The cathode of the diode D3 is connected to the second end B of the switch switching module 400 and the fifth end of the full-bridge rectifier unit 310, and the anode is connected to the cathode of the diode D4. The anode of the diode D4 is connected to the fourth end D of the switch switching module 400 and the sixth end of the full-bridge rectifier unit 310. The cathode of the diode D3 is also connected to the first end of the full-bridge rectifier unit 310 via the voltage-sharing inductor Lj2 and the voltage-sharing capacitor Cj2 in sequence.

[0065] exist Figure 2 In the preferred embodiment shown, a filter capacitor Co is further included, and the filter capacitor is connected between the third terminal and the sixth terminal of the full-bridge rectifier unit 310 to play a role in filtering and noise reduction. The third terminal and the sixth terminal of the full-bridge rectifier unit 310 are the voltage output terminals Vo+ and Vo-.

[0066] Figure 3 yes Figure 2 The first equivalent circuit diagram of the wide range bidirectional soft switching voltage equalizing circuit is shown. Figure 4 yes Figure 2 The second equivalent circuit diagram of the wide range bidirectional soft switch voltage equalizing circuit is shown in FIG. Figure 2-4 The principles of the preferred embodiments of the present invention are further described as follows.

[0067] When switches K1 and K2 are opened and switch K3 is closed, the equivalent circuit is as follows: Figure 3 shown.

[0068] If the circuit direction is from the PRI side to the SEC side, the PRI side is composed of switch tubes Q1, Q2, Q3, Q4 and transformer T1 to form a full-bridge switch circuit. Switch tubes Q1 and Q4 are turned on at the same time, and switch tubes Q2 and Q3 are turned on at the same time. Switch tubes Q1 & Q4 and switch tubes Q2 & Q3 form an interlocking control to avoid direct conduction. The resonant inductor Lr1, the PRI side excitation inductor Lm1 of transformer T1, and the resonant capacitor Cr1 form an LLC resonant circuit. Therefore, the circuit on the PRI side can be regarded as a full-bridge LLC resonant circuit, and the switch tubes Q1, Q2, Q3, and Q4 can easily achieve zero voltage switching (ZVS). At this time, the SEC side is composed of switch tubes Q5, Q6, Q7, Q8 and resonant capacitor Cr2 to form a voltage doubling half-wave rectifier circuit. The switch tubes Q5 and Q8 are turned on at the same time, and the switch tubes Q6 and Q7 are turned on at the same time. The switch tubes Q5 & Q8 form an interlocking control with the switch tubes Q6 & Q7 to avoid direct conduction. The switch tubes Q5 and Q8 are output half-wave rectification, and the resonant capacitor Cr2 is used as the output voltage doubling capacitor to supply power to the output; the switch tubes Q6 and Q7 are used to store energy for the resonant capacitor Cr2 for half-wave rectification. That is, in half a cycle, the switch tubes Q6 and Q7 are turned on, and the transformer T1 charges the resonant capacitor Cr2 with one times the voltage. In the other half cycle, the voltage of the transformer T1 is added to the voltage of the resonant capacitor Cr2 to form a double voltage. After the double voltage is rectified by the switch tubes Q5 and Q8, a double voltage output is formed.

[0069] If the circuit direction is from the SEC side to the PRI side, the SEC side is composed of switch tubes Q5, Q6, Q7, Q8 and transformer T1 to form a resonant circuit. Switch tubes Q5 and Q8 are turned on at the same time, and switch tubes Q6 and Q7 are turned on at the same time. Switch tubes Q5 & Q8 form an interlocking control with switch tubes Q6 & Q7 to avoid direct conduction. The resonant inductor Lr2, the excitation inductor Lm2 on the SEC side of transformer T1 (which can be converted by the excitation inductor Lm1 on the PRI side of transformer T1 through the transformation ratio), and the resonant capacitor Cr2 form an LLC resonant circuit. At the same time, the resonant capacitor Cr2 also plays a role in sharing 1 / 2 of the output voltage Vo, so that the transformer and switch tubes Q5, Q6, Q7, and Q8 only bear 1 / 2Vo of the output voltage stress. Therefore, the SEC side can also form an LLC resonant circuit, and the switch tubes Q5, Q6, Q7, and Q8 can easily achieve zero voltage switching (ZVS). At this time, the PRI side is composed of switch tubes Q1, Q2, Q3, and Q4 to form a bridge full-wave rectifier circuit. Switch tubes Q1 and Q4 are turned on at the same time, and switch tubes Q2 and Q3 are turned on at the same time. Switch tubes Q1 & Q4 form an interlocking control with switch tubes Q2 & Q3 to avoid direct conduction.

[0070] At this time, the equalizing inductor Lj1, the equalizing capacitor Cj1, the equalizing inductor Lj2, and the equalizing capacitor Cj2 in the first equalizing module 610 and the second equalizing module 620 respectively form the equalizing circuit of the energy storage capacitor Co1 and the energy storage capacitor Co2. Due to the inconsistency of the delay time of the switch tube Q6 and the switch tube Q7 when driving, or the difference in the opening delay time of the switch tube Q6 and the switch tube Q7 themselves, or the influence of stray parameters in the circuit, a current will be generated at the connection midpoint of the switch tube Q6 and the switch tube Q7 and the connection midpoint of the energy storage capacitor Co1 and the energy storage capacitor Co2, and this current will cause the voltage on the energy storage capacitor Co1 and the energy storage capacitor Co2 to be biased. In severe cases, the energy storage capacitor Co1 or the energy storage capacitor Co2 will fail due to exceeding the rated voltage due to excessive bias. In this circuit, the voltage-equalizing inductor Lj1, the voltage-equalizing capacitor Cj1, the voltage-equalizing inductor Lj2, and the voltage-equalizing capacitor Cj2 are designed to convert the uneven voltage energy on the energy storage capacitor Co1 and the energy storage capacitor Co2 to each other to achieve the purpose of voltage equalization, thereby ensuring that the voltage difference between the energy storage capacitor Co1 and the energy storage capacitor Co2 is within a controllable range.

[0071] like Figure 3As shown in the figure, the circuit adopts a half-wave rectification method of 2 times voltage rectification in the forward direction, and 1 / 2 times voltage is transmitted to transformer T1 in the reverse direction, and the voltage equalization circuit ensures that the voltage difference between energy storage capacitor Co1 and energy storage capacitor Co2 is very small, thereby ensuring that switch tubes Q5, Q6, Q7, and Q8 can operate at an output voltage of 1 / 2Vo. Therefore, a switch tube with a rated voltage of 1 / 2Vo_max can be selected. Since the switch tube ZVS zero voltage soft opening is achieved in both the forward and reverse directions, the switching loss can be reduced, the switching efficiency can be improved, the heat dissipation requirement can be reduced, and the size of the module can be reduced.

[0072] When switches K1 and K2 are closed and switch K3 is open, the equivalent circuit is as follows: Figure 4 shown.

[0073] like Figure 4 As shown, this is a standard bidirectional CLLLC circuit, and the switch tubes Q5, Q6, Q7, and Q8 form a full-wave rectification.

[0074] If the circuit direction is from the PRI side to the SEC side, the PRI side is composed of switch tubes Q1, Q2, Q3, Q4 and transformer T1 to form a full-bridge switch circuit. Switch tubes Q1 and Q4 are turned on at the same time, and switch tubes Q2 and Q3 are turned on at the same time. Switch tubes Q1 & Q4 and switch tubes Q2 & Q3 form an interlocking control to avoid direct conduction. The resonant inductor Lr1, the PRI side excitation inductor Lm1 of transformer T1, and the resonant capacitor Cr1 form an LLC resonant circuit. Therefore, the PRI can be regarded as a full-bridge LLC resonant circuit, and the switch tubes Q1, Q2, Q3, and Q4 can easily achieve zero voltage switching (ZVS). At this time, the SEC side is composed of switch tubes Q5, Q6, Q7, and Q8 to form a bridge full-wave rectifier circuit. The switch tubes Q5 and Q8 are turned on at the same time, the switch tubes Q6 and Q7 are turned on at the same time, and the switch tubes Q5 & Q8 form an interlocking control with the switch tubes Q6 & Q7 to avoid direct conduction.

[0075] If the circuit direction is from the SEC side to the PRI side, this is similar to the conversion from the PRI side to the SEC side. The SEC side is composed of switch tubes Q5, Q6, Q7, Q8 and transformer T1 to form a resonant circuit. Switch tubes Q5 and Q8 are turned on at the same time, and switch tubes Q6 and Q7 are turned on at the same time. Switch tubes Q5 & Q8 form an interlocking control with switch tubes Q6 & Q7 to avoid direct conduction. The resonant inductor Lr2, the SEC side excitation inductor Lm2 of transformer T1 (which can be converted by the PRI side excitation inductor Lm1 of transformer T1 through the transformation ratio), and the resonant capacitor Cr2 form an LLC resonant circuit. Therefore, the SEC side can also form an LLC resonant circuit, and the switch tubes Q5, Q6, Q7, and Q8 can easily achieve zero voltage switching (ZVS). At this time, the PRI side is composed of switch tubes Q1, Q2, Q3, and Q4 to form a bridge full-wave rectifier circuit. The switch tubes Q1 and Q4 are turned on at the same time, the switch tubes Q2 and Q3 are turned on at the same time, and the switch tubes Q1 & Q4 form an interlocking control with the switch tubes Q2 & Q3 to avoid direct conduction.

[0076] Therefore, the above CLLLC circuit realizes ZVS zero-voltage soft turning-on of the switch tube in both forward and reverse directions, which can reduce switching losses, improve switching efficiency, reduce heat dissipation requirements, and reduce the size of the module.

[0077] Therefore, the wide range bidirectional soft switching voltage equalizing circuit implemented in the present invention can achieve soft switching regardless of whether the voltage conversion is from the first side to the second side or from the second side to the first side, and can also achieve a wide range of voltage output at the same time, and the entire circuit only needs to use conventional devices, so the cost is low and the conversion efficiency and power density are high.

[0078] In the present invention, by switching the switch module, without changing the LLC resonance, a boost (from PRI to SEC) and a buck (from SEC to PRI) circuit are introduced, and a voltage equalization circuit is added to fine-tune the unbalanced voltage, thereby doubling the output gain of the circuit, and at the same time, there is no need to increase the rated voltage of the switch tube on the SEC side.

[0079] See also Figure 2 It can be seen from the circuit that the present invention realizes high voltage and wide range output (reverse direction as input) on the basis of the ordinary bidirectional resonant circuit without affecting the resonant soft switch, and uses conventional devices. It truly achieves the integrated design technology of soft switching circuit performance, high conversion efficiency and high power density, and low cost. The application range of the circuit has been widely expanded, greatly enhancing its market competitiveness.

[0080] exist Figure 2In the preferred embodiment shown, the switch switching module 400 includes a switch K1, a switch K2 and a switch K3, and the switch K1, the switch K2 and the switch K3 may include switch tubes or relay switches, which may be constructed using any suitable switch module as long as they can be controlled to be turned on or off, so as to achieve conduction between the first terminal A and the second terminal B of the switch switching module 400, conduction between the third terminal C and the fourth terminal D, and disconnection between the second terminal B and the third terminal C; or achieve disconnection between the first terminal A and the second terminal B of the switch switching module 400, disconnection between the third terminal C and the fourth terminal D, and conduction between the second terminal B and the third terminal C. Figures 5A-5E Different designs of switching modules 400 are shown.

[0081] like Figure 5A As shown, the switch K1, the switch K2 and the switch K3 can be implemented by selecting three different electronic switch tubes, which include thyristors, field effect tubes, etc. In this embodiment, the switch tube K1 and the switch tube K2 are switched synchronously, and the switch tube K1 & the switch tube K2 need to form an interlocking control with the switch tube K3 to avoid the positive and negative power supply from being directly connected. When the switch tube K1 & the switch tube K2 are closed and the switch tube K3 is disconnected, the first end A and the second end B of the switch switching module 400 are connected, the third end C and the fourth end D are connected, and the second end B and the third end C are disconnected, and the energy storage capacitor Co1 is connected in parallel with the energy storage capacitor Co2; when the switch tube K1 & the switch tube K2 are disconnected and the switch tube K3 is closed, the first end A and the second end B of the switch switching module 400 are disconnected, the third end C and the fourth end D are disconnected, and the second end B and the third end C are connected, and the energy storage capacitor Co1 is connected in series with the energy storage capacitor Co2.

[0082] like Figure 5B As shown, the switch K1, the switch K2 and the switch K3 can be implemented by selecting three independent relay switches. In this embodiment, the relay switch K1 and the relay switch K2 are switched synchronously, and the relay switch K1 & relay switch K2 need to form an interlocking control with the relay switch K3 to avoid direct connection between the positive and negative power supplies. When the relay switch K1 & relay switch K2 are closed and the relay switch K3 is disconnected, the first end A and the second end B of the switch switching module 400 are connected, the third end C and the fourth end D are connected, and the second end B and the third end C are disconnected, and the energy storage capacitor Co1 is connected in parallel with the energy storage capacitor Co2; when the relay switch K1 & relay switch K2 are disconnected and the relay switch K3 is closed, the first end A and the second end B of the switch switching module 400 are disconnected, the third end C and the fourth end D are disconnected, and the second end B and the third end C are connected, and the energy storage capacitor Co1 is connected in series with the energy storage capacitor Co2. Figure 5BAs shown, each relay switch may include a switch portion and a coil control portion, and the coil control portion may control the closing and opening of the switch portion.

[0083] like Figure 5C As shown, the switch switching module 400 includes a double-pole switch K1, a double-pole switch controller, a single-pole switch K3, and a single-pole switch controller. The first moving contact of the double-pole switch K1 is connected to the first end A of the switch switching module 400, the second moving contact is connected to the fourth end D of the switch switching module 400, the first static contact is connected to the second end B of the switch switching module 400, and the second static contact is connected to the third end C of the switch switching module 400. The double-pole switch K1 controller controls the first moving contact and the second moving contact to simultaneously connect to the first static contact and the second static contact or disconnect from the first static contact and the second static contact. The moving contact of the single-pole switch K3 is connected to the third end C of the switch switching module 400, and the static contact is connected to the second end B of the switch switching module 400. The single-pole switch controller controls the moving contact to connect to the static contact or disconnect from the static contact. The double-pole switch K1 and the single-pole switch K3 are interlocked; the double-pole switch K1 includes a double-pole double-throw switch and a double-pole single-throw switch, and the single-pole switch K3 includes a single-pole double-throw switch and a single-pole single-throw switch.

[0084] exist Figure 5C In the preferred embodiment shown, the double-pole switch controller and the double-pole switch K1 can be the switch part and the coil control part of a double-pole single-throw (or double-throw) switch, respectively, or can be other structures, as long as they can realize the aforementioned control process. Similarly, the single-pole switch K3 and the single-pole switch controller can also be the switch part and the coil control part of a single-pole single-throw (or double-throw) switch, or can be other structures, as long as they can realize the aforementioned control process.

[0085] The double-pole switch K1 and the single-pole switch K3 form an interlocking control to prevent the positive and negative power supply from being directly connected. When the double-pole switch K1 is closed and the single-pole switch K3 is disconnected, the first end A and the second end B of the switch switching module 400 are connected, the third end C and the fourth end D are connected, and the second end B and the third end C are disconnected, and the energy storage capacitor Co1 and the energy storage capacitor Co2 are connected in parallel; when the double-pole switch K1 is disconnected and the single-pole switch K3 is closed, the first end A and the second end B of the switch switching module 400 are disconnected, the third end C and the fourth end D are disconnected, and the second end B and the third end C are connected, and the energy storage capacitor Co1 and the energy storage capacitor Co2 are connected in series.

[0086] like Figure 5DAs shown, the switch switching module 400 may include a single-pole double-throw switch K1, a first switch controller, a single-pole double-throw switch K2, and a second switch controller. The moving contact of the single-pole double-throw switch K1 is connected to the second end B of the switch switching module 400, the normally open contact is connected to the first end A of the switch switching module 400, and the normally closed contact is connected to the third end C of the switch switching module 400; the moving contact of the single-pole double-throw switch K2 is also connected to the third end C of the switch switching module 400, the normally closed contact is connected to the second end B of the switch switching module 400, and the normally open contact is connected to the fourth end D of the switch switching module 400. The first switch controller and the second switch controller respectively synchronously control the moving contact of the single-pole double-throw switch K1 and the moving contact of the single-pole double-throw switch K2 to connect to their corresponding normally open contacts or normally closed contacts.

[0087] exist Figure 5D In the preferred embodiment shown, the single-pole double-throw switch K1, the first switch controller, the single-pole double-throw switch K2 and the second switch controller are respectively the switch part and the coil control part of the single-pole double-throw switch, and can also be other structures as long as it can realize the aforementioned control process.

[0088] The single-pole double-throw switch K1 and the single-pole double-throw switch K2 are synchronously controlled to avoid direct connection between the positive and negative power supplies. When the single-pole double-throw switch K1 and the single-pole double-throw switch K2 are in action (when the normally open contact is connected), the first end A and the second end B of the switch switching module 400 are connected, the third end C and the fourth end D are connected, and the second end B and the third end C are disconnected, and the energy storage capacitor Co1 and the energy storage capacitor Co2 are connected in parallel; when the single-pole double-throw switch K1 and the single-pole double-throw switch K2 (when the normally closed contact is connected), the first end A and the second end B of the switch switching module 400 are disconnected, the third end C and the fourth end D are disconnected, and the second end B and the third end C are connected, and the energy storage capacitor Co1 and the energy storage capacitor Co2 are connected in series.

[0089] like Figure 5E As shown, the switch switching module 400 may include a double-pole double-throw switch K1 and a switch controller. The first moving contact of the double-pole double-throw switch K1 is connected to the second end of the switch switching module 400, the second moving contact is connected to the third end of the switch switching module 400, the first normally open contact is connected to the first end of the switch switching module 400, the second normally open contact is connected to the fourth end of the switch switching module 400, the first normally closed contact is connected to the third end of the switch switching module 400, and the second normally closed contact is connected to the second end of the switch switching module 400; the switch controller controls the first moving contact and the second moving contact of the double-pole double-throw switch K1 to connect to their corresponding normally open contacts or normally closed contacts.

[0090] exist Figure 5EIn the preferred embodiment shown, the double-pole double-throw switch K1 and the switch controller are respectively the switch part and the coil control part of the double-pole double-throw switch, and may also be other structures as long as they can realize the aforementioned control process.

[0091] When the double-pole double-throw switch K1 is actuated (when the normally open contact is connected), the first terminal A and the second terminal B of the switch switching module 400 are connected, the third terminal C and the fourth terminal D are connected, and the second terminal B and the third terminal C are disconnected, and the energy storage capacitor Co1 and the energy storage capacitor Co2 are connected in parallel; when the double-pole double-throw switch K1 is reset (when the normally closed contact is connected), the first terminal A and the second terminal B of the switch switching module 400 are disconnected, the third terminal C and the fourth terminal D are disconnected, and the second terminal B and the third terminal C are connected, and the energy storage capacitor Co1 and the energy storage capacitor Co2 are connected in series.

[0092] By the above method, the switch switching module 400 is controlled in real time, thereby controlling the connection between the first terminal A, the second terminal B, the third terminal C and the fourth terminal D of the switch switching module 400. Whether the voltage conversion is from the first side to the second side or from the second side to the first side, soft switching can be achieved, and a wide range of voltage output can be achieved at the same time. The circuit switches between full-wave rectification and half-wave voltage doubler rectification. Under the premise that the device using the full-wave rectification is not changed, the gain of the LLC is expanded to 2 times (1 / 2 times in the reverse direction), and the circuit can still work in a resonant soft switching working state. A combination of high efficiency and wide voltage range input / output is achieved. Furthermore, various types of switching devices can be used to implement the switch switching module, so the needs of various application scenarios can be met.

[0093] As mentioned above, in the preferred embodiment of the present invention, the first LLC resonant module 100 may be in the form of various resonant circuits, for example, a full-bridge LLC module or a half-bridge LLC module. Figure 6-7 FIG. 1 is a circuit diagram of another preferred embodiment of a wide range bidirectional soft switch voltage equalizing circuit of the present invention. Figure 6-7 As shown in the figure, the PRI side can use not only full-bridge LLC modules but also half-bridge LLC modules. When the PRI side uses the half-bridge LLC module, the principle is the same as that of the full-bridge LLC module, so it will not be described in detail.

[0094] In a further preferred embodiment of the present invention, it is also possible not to use one of the resonant capacitors Lr1 or Lr2, but to obtain it by conversion. These all fall within the protection scope of the present invention. In this case, the circuit can still work in soft switching.

[0095] Although the present invention is described by specific embodiments, it should be understood by those skilled in the art that various changes and equivalent substitutions may be made to the present invention without departing from the scope of the present invention. In addition, various modifications may be made to the present invention for specific situations or materials without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all implementation methods falling within the scope of the claims of the present invention.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wide range bidirectional soft switch voltage balancing circuit, comprising: A transformer, a first LLC resonant module disposed on a first side of the transformer, and a second LLC resonant module disposed on a second side of the transformer; The second LLC resonance module comprises a second LC resonance unit and a full-bridge rectification unit; characterized in that: The wide range bidirectional soft switch voltage balancing circuit further comprises a switch switching module, a first energy storage module, a second energy storage module, a first voltage balancing module and a second voltage balancing module arranged on the second side of the transformer; The first end of the second LC resonance unit is connected to the first end of the second side of the transformer, the second end is connected to the first end of the full-bridge rectifier unit, the third end is connected to the second end of the second side of the transformer, and the fourth end is connected to the second end of the full-bridge rectifier unit; the first energy storage module is connected between the third end and the fourth end of the full-bridge rectifier unit, and the second energy storage module is connected between the fifth end and the sixth end of the full-bridge rectifier unit; The first end of the first voltage balancing module is connected to the third end of the full-bridge rectifier unit, the second end is connected to the fourth end of the full-bridge rectifier unit, and the third end is connected to the second end of the full-bridge rectifier unit; the first end of the second voltage balancing module is connected to the fifth end of the full-bridge rectifier unit, the second end is connected to the sixth end of the full-bridge rectifier unit, and the third end is connected to the first end of the full-bridge rectifier unit; The first end of the switch switching module is connected to the third end of the full-bridge rectifier unit, the second end is connected to the fifth end of the full-bridge rectifier unit, the third end is connected to the fourth end of the full-bridge rectifier unit, and the fourth end is connected to the sixth end of the full-bridge rectifier unit; when the first end and the second end of the switch switching module are connected, the third end and the fourth end are connected, and the second end and the third end are disconnected, the first energy storage module and the second energy storage module are connected in parallel; when the first end and the second end of the switch switching module are disconnected, the third end and the fourth end are disconnected, and the second end and the third end are connected, the first energy storage module and the second energy storage module are connected in series; When the first energy storage module and the second energy storage module are connected in parallel or the first energy storage module and the second energy storage module are connected in series; when the direction of the wide-range bidirectional soft-switching voltage balancing circuit is from the first side of the transformer to the second side of the transformer, the first LLC resonant module realizes soft switching, and when the direction of the wide-range bidirectional soft-switching voltage balancing circuit is from the second side of the transformer to the first side of the transformer, the full-bridge rectifier unit realizes soft switching.

2. The wide range bidirectional soft switch voltage balancing circuit according to claim 1, characterized in that: The switch switching module comprises a first switch, a second switch and a third switch, wherein the first switch is connected between the first end and the second end of the switch switching module, the second switch is connected between the third end and the fourth end of the switch switching module, and the third switch is connected between the second end and the third end of the switch switching module; The first switch, the second switch and the third switch respectively include switch tubes or relay switches; The first switch and the second switch are synchronized, and the first switch and the second switch are interlocked with the third switch.

3. The wide range bidirectional soft switch voltage balancing circuit according to claim 1, characterized in that: The switch switching module includes a double-pole switch, a double-pole switch controller, a single-pole switch and a single-pole switch controller; The first moving contact of the double-pole switch is connected to the first end of the switch switching module, the second moving contact is connected to the fourth end of the switch switching module, the first static contact is connected to the second end of the switch switching module, and the second static contact is connected to the third end of the switch switching module; the double-pole switch controller controls the first moving contact and the second moving contact to simultaneously connect to the first static contact and the second static contact respectively or to disconnect from the first static contact and the second static contact; The moving contact of the single-pole switch is connected to the third end of the switch switching module, and the static contact is connected to the second end of the switch switching module, and the single-pole switch controller controls the moving contact to connect with or disconnect from the static contact; The double-pole switch and the single-pole switch are interlocked; The double-pole switch includes a double-pole double-throw switch and a double-pole single-throw switch, and the single-pole switch includes a single-pole double-throw switch and a single-pole single-throw switch.

4. The wide range bidirectional soft switch voltage balancing circuit according to claim 1, characterized in that: The switch switching module includes a first single-pole double-throw switch, a first switch controller, a second single-pole double-throw switch and a second switch controller; The moving contact of the first single-pole double-throw switch is connected to the second end of the switch switching module, the normally open contact is connected to the first end of the switch switching module, and the normally closed contact is connected to the third end of the switch switching module; the moving contact of the second single-pole double-throw switch is also connected to the third end of the switch switching module, the normally closed contact is connected to the second end of the switch switching module, and the normally open contact is connected to the fourth end of the switch switching module; The first switch controller and the second switch controller synchronously control the moving contact of the first single-pole double-throw switch and the moving contact of the second single-pole double-throw switch to connect to their corresponding normally open contacts or normally closed contacts.

5. The wide range bidirectional soft switch voltage balancing circuit according to claim 1, characterized in that: The switch switching module includes a double-pole double-throw switch and a switch controller; The first moving contact of the double-pole double-throw switch is connected to the second end of the switch switching module, the second moving contact is connected to the third end of the switch switching module, the first normally open contact is connected to the first end of the switch switching module, the second normally open contact is connected to the fourth end of the switch switching module, the first normally closed contact is connected to the third end of the switch switching module, and the second normally closed contact is connected to the second end of the switch switching module; The switch controller controls the first moving contact and the second moving contact of the double-pole double-throw switch to connect to their corresponding normally open contacts or normally closed contacts.

6. The wide range bidirectional soft switch voltage balancing circuit according to any one of claims 1 to 5, characterized in that: The first voltage balancing module includes a first diode, a second diode, a first voltage balancing inductor and a first voltage balancing capacitor. The cathode of the first diode is connected to the first end of the switch switching module and the third end of the full-bridge rectifier unit, and the anode is connected to the cathode of the second diode. The anode of the second diode is connected to the third end of the switch switching module and the fourth end of the full-bridge rectifier unit. The cathode of the first diode is also connected to the second end of the full-bridge rectifier unit via the first voltage balancing inductor and the first voltage balancing capacitor in sequence.

7. The wide range bidirectional soft switch voltage balancing circuit according to claim 6, characterized in that: The second voltage balancing module includes a third diode, a fourth diode, a second voltage balancing inductor and a second voltage balancing capacitor. The cathode of the third diode is connected to the second end of the switch switching module and the fifth end of the full-bridge rectifier unit, and the anode is connected to the cathode of the fourth diode. The anode of the fourth diode is connected to the fourth end of the switch switching module and the sixth end of the full-bridge rectifier unit. The cathode of the third diode is also connected to the first end of the full-bridge rectifier unit via the second voltage balancing inductor and the second voltage balancing capacitor in sequence.

8. The wide range bidirectional soft switch voltage balancing circuit according to claim 7, characterized in that: The full-bridge rectifier unit includes a switch tube Q5, a switch tube Q6, a switch tube Q7 and a switch tube Q8. The control ends of the switch tubes Q5, Q6, Q7 and Q8 receive control signals respectively. The first end of the switch tube Q5 is connected to the first end of the full-bridge rectifier unit and the second end of the switch tube Q6. The second end of the switch tube Q5 is connected to the third end of the full-bridge rectifier unit. The first end of the switch tube Q6 is connected to the fourth end of the full-bridge rectifier unit. The first end of the switch tube Q7 is connected to the second end of the full-bridge rectifier unit and the second end of the switch tube Q8. The second end of the switch tube Q7 is connected to the fifth end of the full-bridge rectifier unit. The first end of the switch tube Q8 is connected to the sixth end of the full-bridge rectifier unit.

9. The wide range bidirectional soft switch voltage balancing circuit according to claim 8, characterized in that: The second LC resonance unit includes a second resonance inductor and a second resonance capacitor; The first end of the second resonant inductor is connected to the first end of the second side of the transformer, and the second end is connected to the first end of the full-bridge rectifier unit; the first end of the second resonant capacitor is connected to the second end of the second side of the transformer, and the second end is connected to the second end of the full-bridge rectifier unit; or The second resonant inductor and the second resonant capacitor are connected in series between the first end of the second side of the transformer and the first end of the full-bridge rectifier unit; or The second resonant inductor and the second resonant capacitor are connected in series between the second end of the second side of the transformer and the second end of the full-bridge rectifier unit; or The first end of the second resonant capacitor is connected to the first end of the second side of the transformer, and the second end is connected to the first end of the full-bridge rectifier unit. The first end of the second resonant inductor is connected to the second end of the second side of the transformer, and the second end is connected to the second end of the full-bridge rectifier unit.

10. The wide range bidirectional soft switch voltage balancing circuit according to claim 8, characterized in that: The first LLC resonant module includes a full-bridge LLC module or a half-bridge LLC module.

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