WO2024051317A1

WO2024051317A1 - Three-phase-interleaving extended-range efficient-isolation bidirectional converter

Info

Publication number: WO2024051317A1
Application number: PCT/CN2023/104672
Authority: WO
Inventors: 向小路; 李俊敏
Original assignee: 深圳深源技术能源有限公司
Priority date: 2022-09-09
Filing date: 2023-06-30
Publication date: 2024-03-14
Also published as: CN115580150A

Abstract

Disclosed in the present application is a three-phase-interleaving extended-range efficient-isolation bidirectional converter, comprising a three-phase bridge type switching circuit, a resonant cavity, three transformers and a three-phase bridge type rectifying circuit. The resonant cavity comprises three resonant circuits, and each resonant circuit comprises a first capacitor, a second capacitor, a third capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor is connected to one end of the second inductor, one end of the first capacitor and one end of the third capacitor, and the other ends of the first inductor and the first capacitor are respectively connected to one end of the third inductor and one end of the second capacitor. Said end of the third inductor is connected to the midpoint of a bridge arm in the three-phase bridge type switching circuit, and the other ends of the second inductor and the third capacitor are respectively connected to the other ends of the third inductor and the second capacitor and are connected to a primary winding of a transformer. In the three resonant circuits, the ends of the second capacitors connected to the first capacitors are connected to each other to form a Y-shaped connection. Secondary windings of the three transformers are respectively connected to the midpoints of the three bridge arms of the three-phase bridge type rectifying circuit.

Description

A three-phase interleaved wide-range high-efficiency isolated bidirectional converter

This application is based on the Chinese patent application with application number 202211104680.2 and a filing date of September 9, 2022, and claims its priority. The entire content of the application is hereby incorporated into this application as a whole.

Technical field

This application relates to the field of power conversion technology, and more specifically to a three-phase interleaved wide-range high-efficiency isolated bidirectional converter.

Background technique

DC-DC bidirectional converter is a DC/DC converter that can adjust the two-way transmission of energy according to needs. It is mainly used in energy storage systems, vehicle power systems, feedback charging and discharging systems, hybrid energy electric vehicles and other occasions. As the industry continues to With the development, the power continues to increase from kilowatt level to tens of kilowatt level, and topologies that can achieve high power, wide range, forward and reverse symmetric bidirectional, and high efficiency have become the general trend.

In the traditional LLC resonant bidirectional converter, ZVS conduction of the primary side switch tube and ZCS conduction of the rectifier side diode can be achieved regardless of forward and reverse operation. However, when the energy flows in the reverse direction, its circuit characteristics no longer It is the LLC resonance characteristic and degenerates into the LC resonance characteristic. The maximum voltage gain of the LC resonance becomes 1, which greatly reduces the voltage gain during reverse operation and cannot achieve normal output in the reverse direction, making it impossible to achieve complete symmetry in both forward and reverse directions; In order to achieve completely symmetrical bidirectional energy flow, the industry uses DAB or adds a one-level topology circuit based on LLC to make up for the lack of LLC reverse gain capability and basically achieve completely symmetrical bidirectionality. However, the DAB hard switch and LLC two-level topology architecture, will bring about the problem of low efficiency, especially for higher power bidirectional DC-DC. Due to the inherent problems of DAB or two-stage topology, as the power continues to increase, the heat and ripple of high-power bidirectional DC-DC will become increasingly large. It is difficult to handle and will eventually become a bottleneck.

Application content

The technical problem to be solved by this application is to provide a three-phase interleaved wide-range high-efficiency isolated bidirectional converter that can reduce ripple while achieving wide range, completely symmetrical forward and reverse gains and high efficiency.

In order to solve the above technical problems, this application provides a three-phase interleaved wide range high-efficiency isolated bidirectional converter, including a three-phase bridge switching circuit, a resonant cavity, three transformers and a three-phase bridge rectifier circuit. The three-phase bridge One side of the switching circuit and the three-phase bridge rectifier circuit serves as the first connection side and the second connection side of the three-phase interleaved wide-range high-efficiency isolation bidirectional converter respectively. The resonant cavity includes three resonant circuits, and the three resonant circuits The circuits are respectively connected between the midpoints of the three bridge arms of the three-phase bridge switch circuit and the primary windings of the three transformers, where,

The resonant circuit includes a first capacitor, a second capacitor, a third capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor is connected to one end of the second inductor, the first capacitor and the third capacitor. , the other ends of the first inductor and the first capacitor are respectively connected to one end of the third inductor and the second capacitor, and the one end of the third inductor is connected to the midpoint of a bridge arm in the three-phase bridge switch circuit, and the third The other ends of the second inductor and the third capacitor are respectively connected to the other ends of the third inductor and the second capacitor, and connected to the primary winding of a transformer, and the ends of the second capacitor and the first capacitor in the three resonant circuits are connected to each other respectively. The connections form a Y-shaped connection. The same-named ends of the three transformer secondary windings correspond to the midpoints of the three bridge arms connected to the three-phase bridge rectifier circuit. The different-named ends of the three transformer secondary windings are connected to each other to form a Y-shaped connection. .

The further technical solution is: the three-phase bridge switch circuit includes six switch tubes, and each two switch tubes are connected in series to form a bridge arm. After the three bridge arms are connected in parallel, its two ends serve as a three-phase interleaved wide-range high-efficiency isolation bidirectional conversion. the first connection side of the device.

The further technical solution is: the three-phase bridge rectifier circuit includes six switch tubes, and each two switch tubes are connected in series to form a bridge arm. After the three bridge arms are connected in parallel, their two ends serve as a three-phase interleaved wide range high-efficiency isolation bidirectional conversion. the second connection side of the device.

The further technical solution is: the switching tube is selected from MOSFET, IGBT tube, GaN tube or SiC power tube.

Its further technical solution is: the three-phase interleaved wide-range high-efficiency isolated bidirectional converter also includes a first filter capacitor and a second filter capacitor, and both ends of the first filter capacitor are connected to the three-phase interleaved wide-range high-efficiency isolated bidirectional converter. The first connection side of the second filter capacitor is connected to the second connection side.

In order to solve the above technical problems, this application also provides a three-phase interleaved wide range high-efficiency isolated bidirectional converter, including a three-phase bridge switching circuit, a resonant cavity, three transformers and a three-phase bridge rectifier circuit. The three-phase bridge One side of the switch circuit and the three-phase bridge rectifier circuit serves as the first connection side and the second connection side of the three-phase interleaved wide-range high-efficiency isolated bidirectional converter respectively. The resonant cavity includes three resonant circuits, and the three resonant circuits are The resonant circuits are respectively connected to the midpoints of the three bridge arms of the three-phase bridge switch circuit and between the three primary windings of the transformer, where,

The resonant circuit includes a first capacitor, a second capacitor, a third capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor is connected to one end of the second inductor, the first capacitor and the third capacitor. , the other ends of the first inductor and the first capacitor are respectively connected to one end of the third inductor and the second capacitor, and the one end of the second capacitor is connected to the midpoint of a bridge arm in the three-phase bridge switch circuit, and the third The other ends of the second inductor and the third capacitor are respectively connected to the other ends of the third inductor and the second capacitor, and connected to the primary winding of a transformer, and one end of the third inductor and the first inductor in the three resonant circuits are connected to each other respectively. The connections form a Y-shaped connection. The same-named ends of the three transformer secondary windings correspond to the midpoints of the three bridge arms connected to the three-phase bridge rectifier circuit. The different-named ends of the three transformer secondary windings are connected to each other to form a Y-shaped connection. .

The resonant circuit includes a first capacitor, a second capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor and the second inductor is connected to one end of the first capacitor and the second capacitor. The other end of an inductor is connected to one end of the third inductor and to the midpoint of a bridge arm in the three-phase bridge switch circuit, the other ends of the second inductor and the second capacitor are connected to the primary winding of a transformer, and The other end of the second inductor is connected to the other end of the third inductor. The other ends of the first capacitors in the three resonant circuits are connected to each other to form a Y-shaped connection. The same ends of the three transformer secondary windings are connected to three corresponding ends. The midpoints of the three bridge arms of the phase bridge rectifier circuit and the opposite ends of the three transformer secondary windings are connected to each other to form a Y-shaped connection.

The resonant circuit includes a first capacitor, a second capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor is connected to the first capacitor and one end of the third inductor. One end of the second inductor The other end of the third inductor is connected to one end of the second capacitor. The other end of the first capacitor is connected to the midpoint of one bridge arm in the three-phase bridge switch circuit. The other end of the second inductor is connected to the second capacitor. The primary winding of a transformer, and the other end of the second inductor is connected to the other end of the first inductor, and the identical ends of the secondary windings of the three transformers are respectively connected to the midpoints of the three bridge arms of the three-phase bridge rectifier circuit, The opposite ends of the primary windings and secondary windings of the three transformers are connected to each other to form a Y-shaped connection.

Compared with the existing technology, each circuit in the three-phase interleaved wide-range high-efficiency isolated bidirectional converter of the present application adopts three-phase interleaved technology to reduce ripples, and the equivalent circuit of the resonant circuit is even when the energy flows forward and reverse. It is a multi-component resonant circuit, which realizes soft switching when working in forward and reverse directions, and the loss is small, which solves the problem that the traditional LLC resonant circuit cannot work with the same performance in the reverse direction. That is, the three-phase interleaved wide range high-efficiency isolated bidirectional converter of the present application can perform energy reverse operation. The voltage can be boosted when flowing in the forward direction, which can effectively increase the input and output voltage range of the converter and achieve a wide voltage range output. At the same time, the gain is the same when the energy flows forward and reverse. Moreover, the structural design of the resonant circuit of this application, when using switching frequency modulation control, A wide voltage range output can be achieved without wide-band control, that is, the switching control frequency can be compressed and narrowed to improve efficiency.

Description of the drawings

Figure 1 is a circuit schematic diagram of the first embodiment of the three-phase interleaved wide-range high-efficiency isolated bidirectional converter of the present application.

Figure 2 is a circuit schematic diagram of the second embodiment of the three-phase interleaved wide-range high-efficiency isolated bidirectional converter of the present application.

Figure 3 is a circuit schematic diagram of the third embodiment of the three-phase interleaved wide-range high-efficiency isolated bidirectional converter of the present application.

Figure 4 is a circuit schematic diagram of the fourth embodiment of the three-phase interleaved wide-range high-efficiency isolated bidirectional converter of the present application.

Implementation

In order to enable those of ordinary skill in the art to more clearly understand the purpose, technical solutions and advantages of the present application, the present application will be further elaborated below in conjunction with the accompanying drawings and examples.

Referring to FIG. 1 , FIG. 1 is a circuit schematic diagram of a first embodiment of a three-phase interleaved wide-range high-efficiency isolated bidirectional converter 10 of the present application. In the embodiment shown in the drawings, the three-phase interleaved wide-range high-efficiency isolated bidirectional converter 10 includes a three-phase bridge switching circuit 100, a resonant cavity 200, three transformers and a three-phase bridge rectifier circuit 300. One side of the three-phase bridge switching circuit 100 and the three-phase bridge rectifier circuit 300 serves as the first connection side and the second connection side of the converter 10 respectively to connect the power supply or the load. The resonant cavity 200 includes three resonators. circuit, the three resonant circuits are respectively connected between the midpoints of the three bridge arms of the three-phase bridge switch circuit 100 and the three primary windings of the transformer. Wherein, the resonant circuit includes a first capacitor, a second capacitor, a third capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor is connected to the second inductor, the first capacitor and the third capacitor. One end of the first inductor and the first capacitor is connected to one end of the third inductor and the second capacitor respectively, and the one end of the third inductor is connected to the midpoint of one bridge arm in the three-phase bridge switch circuit 100, The other ends of the second inductor and the third capacitor are respectively connected to the other ends of the third inductor and the second capacitor, and connected to the primary winding of a transformer, and the second capacitor is connected to the first capacitor in the three resonant circuits. One end is connected to each other to form a Y-shaped connection, the same-named ends of the three transformer secondary windings are respectively connected to the midpoints of the three bridge arms of the three-phase bridge rectifier circuit 300, and the different-named ends of the three transformer secondary windings are respectively connected to each other. Form a Y-shaped connection. Preferably, the first inductor and the second inductor in the resonant circuit have the same inductance, and the first capacitor and the third capacitor have the same capacitance. Understandably, a Y-shaped connection is used in the resonant circuit. The total current flowing into the midpoint of the Y-shaped connection is equal to the total current flowing out of the midpoint of the Y-shaped connection. That is, the sum of the currents of the three resonant circuits is "0", so any At all times, the current of one resonant circuit is the sum of the currents of the other two resonant circuits. Even if the resonant parameters of each resonant circuit have a certain tolerance during the entire switching cycle, the deviation of their current effective values is also very small. This ensures the current balance between the three resonant circuits and prevents excessive current in one resonant circuit from causing damage or overheating of components in the circuit.

Specifically, in this embodiment, the resonant cavity 200 includes a first resonant circuit, a second resonant circuit and a third resonant circuit, and the three transformers include a first transformer T1, a second transformer T2 and a third transformer T3. The first resonant circuit includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a first inductor L1, a second inductor L2 and a third inductor L3. The second resonant circuit includes a first capacitor C4, a second capacitor C4 and a third inductor L3. C5, the third capacitor C6, the first inductor L4, the second inductor L5 and the third inductor L6. The third resonant circuit includes the first capacitor C7, the second capacitor C8, the third capacitor C9, the first inductor L7 and the third inductor L6. The second inductor L8 and the third inductor L9. In the embodiment shown in the drawing, the third inductor L3, the third inductor L6 and the third inductor L9 respectively correspond to the three inductors connected to the three-phase bridge switch circuit 100. At the midpoint of the bridge arm, the second capacitor C2, the second capacitor C5 and the second capacitor C8 are respectively connected to each other to form a Y-shaped connection, and the second inductor L2, the second inductor L5 and the second inductor L8 are respectively connected to the first transformer T1, The same terminals of the primary windings of the second transformer T2 and the third transformer T3; and the third capacitor C3, the third capacitor C6 and the third capacitor C9 are respectively connected to the terminals of the primary windings of the first transformer T1, the second transformer T2 and the third transformer T3. Alien name.

In this embodiment, when energy flows in the forward direction, that is, when energy flows from the first connection side to the second connection side, the first connection side of the three-phase interleaved wide-range high-efficiency isolation bidirectional converter 10 serves as the DC input end and can be connected externally. The second connection side of the power supply serves as the DC output end and can be connected to an external load; when the energy flows in the reverse direction, that is, when the energy flows from the second connection side to the first connection side, the three-phase interleaved wide range high-efficiency isolation bidirectional converter The second connection side of 10 serves as the DC input end, and the first connection side serves as the DC output end. The three-phase interleaved wide-range high-efficiency isolated bidirectional converter 10 of the present application has a simple structure. When the energy flows in the forward and reverse directions, the equivalent circuit of the resonant circuit is a multi-element resonant circuit. Soft switching can be achieved in both forward and reverse operation, and the loss is small. It solves the problem of insufficient reverse gain of the traditional LLC resonant circuit, that is, the voltage can be boosted when energy flows from the second connection side to the first connection side, which can effectively increase the input and output voltage range of the converter 10 and achieve a wide voltage range input and output. , can be applied to high-power circuits; and compared with the switching frequency of the three-phase interleaved bidirectional converter in the prior art, which requires wide-band control to achieve a wide range of voltage input and output, the three-phase interleaved wide-range high-efficiency isolated bidirectional converter of this application 10 Because the resonant frequency of the redesigned resonant circuit is smaller, wide-voltage range output can be achieved without wide-band control when using switching frequency modulation control, that is, the switching control frequency can be compressed and narrowed to improve efficiency.

In some embodiments, the three-phase bridge switch circuit 100 includes a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, a fifth switch Q5, and a sixth switch. Tube Q6 has a total of six switching tubes, and each two switching tubes are connected in series to form a bridge arm. After the three bridge arms are connected in parallel, its two ends serve as the first connection side of the three-phase interleaved wide range high-efficiency isolation bidirectional converter 10, wherein, the The midpoint of the bridge arm formed by the series connection of the first switching tube Q1 and the second switching tube Q2 is connected to the first resonant circuit. The midpoint of the bridge arm formed by the series connection of the third switching tube Q3 and the fourth switching tube Q4 is connected with the second resonant circuit. The resonant circuit is connected, and the midpoint of the bridge arm formed by the series connection of the fifth switching tube Q5 and the sixth switching tube Q6 is connected to the third resonant circuit. In this embodiment, the PFM method is used to control the operation of the switching tube, that is, a constant duty cycle is used to constant the on and off times of the switching tube, and then the square wave frequency is modulated to achieve adjustment. Three methods in the existing technology The switching frequency of the interleaved bidirectional converter requires wide-bandwidth control to achieve a wide range of voltage input and output. That is, when 40v needs to be boosted to 400v, the switching frequency needs to be at full load. The frequency is as high as 200KHZ at full load and as high as 250KHZ at no load. However, the switching frequency control range of the three-phase interleaved wide-range high-efficiency isolated bidirectional converter 10 of this application is relatively small. When the boost gain is the same, the switching frequency is only 160KHZ at full load, and the efficiency is high.

In the embodiment shown in the drawings, the three-phase bridge rectifier circuit 300 includes a seventh switching tube Q7, an eighth switching tube Q8, a ninth switching tube Q9, a tenth switching tube Q10, and an eleventh switching tube Q11. and the twelfth switching tube Q12 and six switching tubes. Each two switching tubes are connected in series to form a bridge arm. After the three bridge arms are connected in parallel, their two ends serve as the second connection side of the three-phase interleaved wide range high-efficiency isolation bidirectional converter 10. Among them, the midpoint of the bridge arm formed by the series connection of the seventh switching tube Q7 and the eighth switching tube Q8 is connected to the secondary winding of the first transformer T1, and the ninth switching tube Q9 and the tenth switching tube Q10 are connected in series. The midpoint of the bridge arm is connected to the secondary winding of the second transformer T2, and the midpoint of the bridge arm composed of the eleventh switching transistor Q11 and the twelfth switching transistor Q12 connected in series is connected to the secondary winding of the third transformer T3. Based on this design, when energy flows in the forward direction, the three-phase bridge rectifier circuit 300 can rectify the voltage waveform periodically output by the transformer to generate the operating voltage required by the load. Preferably, the switch tube can be a MOSFET, IGBT tube, GaN tube, SiC power tube or other controllable power switch tube to achieve better circuit performance. In some other embodiments, on each switch tube A diode can also be connected in parallel.

Further, the three-phase interleaved wide-range high-efficiency isolated bidirectional converter 10 also includes a first filter capacitor C10 and a second filter capacitor C11. Both ends of the first filter capacitor C10 are connected to the three-phase interleaved wide-range high-efficiency isolated bidirectional converter. The first connection side of the converter 10, and both ends of the second filter capacitor C11 are connected to the second connection side of the three-phase interleaved wide range high-efficiency isolation bidirectional converter 10.

It can be understood that in this embodiment, when energy is transmitted in the forward direction, by controlling the first switching tube Q1, the second switching tube Q2, the third switching tube Q3, the fourth switching tube Q4, the fifth switching tube Q5 and the sixth switching tube Q5. The switching frequency of the switch tube Q6 is used to realize the wide range voltage output of the three-phase interleaved wide range high-efficiency isolation bidirectional converter 10, and the two switch tubes on each bridge arm are complementary to conduct, which can realize soft switching of the circuit; reverse energy transmission When , the equivalent circuit of the resonant circuit is also a multi-element resonant circuit. Therefore, by controlling the seventh switching tube Q7, the eighth switching tube Q8, the ninth switching tube Q9, the tenth switching tube Q10, the eleventh switching tube Q11 and The switching frequency of the twelfth switch Q12 can achieve the same wide range voltage output as during forward transmission, and the two switch tubes on each bridge arm are complementary to conduct, realizing soft switching of the circuit.

The three-phase interleaved wide-range high-efficiency isolated bidirectional converter 10 of this application adopts three-phase interleaved technology. The conduction phase differences between Q1 and Q2, Q3 and Q4, Q5 and Q6 are all 180 degrees. The conduction timing of Q1, Q3 and Q5 is The difference is 120 degrees from each other; therefore, the conduction timings of Q2, Q4, and Q6 are also 120 degrees different from each other, and the three-phase input and output currents are 120 degrees different from each other. The input and output current fluctuations of the three-phase circuit are complementary, making the input and output current ripples smaller, thus Achieve better circuit performance. At any time, at least one and at most two of Q1, Q3, and Q5 will be turned on. Similarly, at least one and at most two of Q2, Q4, and Q6 will be turned on, and the number of turned-on switch tubes is always equal to three. Taking one of the three resonant circuits as an example, when Q1, Q4 and Q6 are turned on, the resonant DC voltage is transmitted to the first transformer T1 through the first switch Q1. At the same time, the current value of the first resonant circuit increases and is stored. Yes, at the same time, the seventh switching tube Q7 is turned on, and the second filter capacitor C11 realizes rectification and filtering of the output voltage of the first transformer T1 to output a stable voltage and control the output current; when Q2, Q3 and Q5 are turned on , the resonant DC reverse voltage is transmitted to the first transformer T1 through the second switching tube Q2. At the same time, the reverse current value of the first resonant circuit increases, supplying power to the first transformer T1, and the eighth switching tube Q8 is turned on to realize the power supply to the first transformer T1. The output voltage of a transformer T1 is rectified and filtered to output a stable voltage and control the output current. In the same way, the working principles of the other two resonant circuits are consistent with this circuit.

Referring to Figure 2, Figure 2 is a circuit schematic diagram of the second embodiment of the three-phase interleaved wide range high-efficiency isolated bidirectional converter 10 of the present application. The difference between this embodiment and the first embodiment lies in the resonant circuit and the inverter circuit in the resonant cavity 200. As well as the specific connections of the transformer are different, the rest of the circuit structure is the same or similar. In this embodiment, the midpoint of the bridge arm formed by the series connection of the first switch Q1 and the second switch Q2 is connected to the second capacitor C2 in the first resonant circuit, and the third switch Q3 and the fourth switch The midpoint of the bridge arm formed by the series connection of the tube Q4 is connected to the second capacitor C5 in the second resonant circuit. The midpoint of the bridge arm formed by the series connection of the fifth switching tube Q5 and the sixth switching tube Q6 is connected with the third capacitor C5 in the third resonant circuit. The two capacitors C8 are connected, the third inductor L3, the third inductor L6 and the third inductor L9 are respectively connected to each other to form a Y-shaped connection, the third capacitor C3, the third capacitor C6 and the third capacitor C9 are respectively connected to the first transformer T1 , the same terminals of the primary windings of the second transformer T2 and the third transformer T3; and the second inductor L2, the second inductor L5 and the second inductor L8 are respectively connected to the primary windings of the first transformer T1, the second transformer T2 and the third transformer T3. The opposite name.

Referring to Figure 3, Figure 3 is a circuit schematic diagram of the third embodiment of the three-phase interleaved wide range high-efficiency isolated bidirectional converter 10 of the present application. The difference between this embodiment and the first embodiment lies in the specific structure of the resonant circuit in the resonant cavity 200. , the rest of the circuit structures are the same or similar. In this embodiment, the resonant circuit includes a first capacitor, a second capacitor, a first inductor, a second inductor and a third inductor. One ends of the first inductor and the second inductor are connected to the first capacitor and the second capacitor. One end of the first inductor is connected to one end of the third inductor and connected to the midpoint of a bridge arm in the three-phase bridge switch circuit. The other ends of the second inductor and the second capacitor are connected to a transformer. The primary winding, and the other end of the second inductor is connected to the other end of the third inductor, and the other ends of the first capacitors in the three resonant circuits are connected to each other to form a Y-shaped connection.

As can be seen from the figure, specifically, the resonant cavity 200 includes a first resonant circuit, a second resonant circuit and a third resonant circuit. The first resonant circuit includes a first capacitor C1, a second capacitor C2, a first inductor L1, the second inductor L2 and the third inductor L3. The second resonant circuit includes a first capacitor C3, a second capacitor C4, a first inductor L4, a second inductor L5 and a third inductor L6. The third resonant circuit includes a A capacitor C5, a second capacitor C6, a first inductor L7, a second inductor L8 and a third inductor L9. In the embodiment shown in the drawing, the third inductor L3, the third inductor L6 and the third inductor L9 One end of the third inductor L3, the third inductor L6 and the third inductor L9 respectively connects to the midpoint of the three bridge arms of the three-phase bridge switch circuit 100, and the other ends of the third inductor L3, the third inductor L6 and the third inductor L9 respectively connect to the first transformer T1, The same terminals of the primary windings of the second transformer T2 and the third transformer T3, the second capacitor C2, the second capacitor C4 and the second capacitor C6 are respectively connected to the same terminals of the primary windings of the first transformer T1, the second transformer T2 and the third transformer T3. terminal, the first capacitor C1, the first capacitor C3 and the first capacitor C5 are respectively connected to each other to form a Y-shaped connection. This embodiment can also effectively increase the input and output voltage range of the converter 10 to achieve a wide voltage range input and output, and when using switching frequency modulation control, a wide voltage range output can be achieved without wide frequency control, that is, the switching control frequency can be compressed and narrowed. ,Improve efficiency.

Referring to Figure 4, Figure 4 is a circuit schematic diagram of the fourth embodiment of the three-phase interleaved wide range high-efficiency isolated bidirectional converter 10 of the present application. The difference between this embodiment and the first embodiment lies in the specific structure of the resonant circuit in the resonant cavity 200. , the rest of the circuit structures are the same or similar. In this embodiment, the resonant circuit includes a first capacitor, a second capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor is connected to one end of the first capacitor and the third inductor. One end of the second inductor is connected to the other end of the third inductor and one end of the second capacitor, the other end of the first capacitor is connected to the midpoint of a bridge arm in the three-phase bridge switch circuit, the second inductor and the second The other end of the capacitor is connected to the primary winding of a transformer, and the other end of the second inductor is connected to the other end of the first inductor.

As can be seen from the figure, specifically, the resonant cavity 200 includes a first resonant circuit, a second resonant circuit and a third resonant circuit. The first resonant circuit includes a first capacitor C1, a second capacitor C2, a first inductor L1, the second inductor L2 and the third inductor L3. The second resonant circuit includes a first capacitor C3, a second capacitor C4, a first inductor L4, a second inductor L5 and a third inductor L6. The third resonant circuit includes a A capacitor C5, a second capacitor C6, a first inductor L7, a second inductor L8 and a third inductor L9. In the embodiment shown in the drawing, the first capacitor C1, the first capacitor C3 and the first capacitor C5 The second capacitor C2, the second capacitor C4, and the second capacitor C6 are respectively connected to the midpoints of the three bridge arms of the three-phase bridge switch circuit 100, and the second capacitor C2, the second capacitor C4, and the second capacitor C6 are respectively connected to the first transformer T1, the second transformer T2, and the second transformer T2. The same-name terminal of the primary winding of the third transformer T3, the second inductor L2, the second inductor L5 and the second inductor L8 are respectively connected to the different-name terminals of the primary windings of the first transformer T1, the second transformer T2 and the third transformer T3, And the opposite ends of the primary winding and the secondary winding of the first transformer T1, the second transformer T2 and the third transformer T3 are respectively connected to each other to form a Y-shaped connection.

In summary, each circuit in the three-phase interleaved wide-range high-efficiency isolated bidirectional converter of the present application adopts three-phase interleaved technology to reduce ripples, and the equivalent circuit of the resonant circuit in the forward and reverse flow of energy is multi-element. The resonant circuit realizes soft switching during forward and reverse operation, and the loss is small, which solves the problem that the traditional LLC resonant circuit cannot work with the same performance in the reverse direction, that is, the three-phase interleaved wide range high-efficiency isolation bidirectional converter of the present application flows in the reverse direction of energy. The voltage can be boosted at any time, which can effectively increase the input and output voltage range of the converter and achieve a wide voltage range output. At the same time, the gain is the same when the energy flows forward and reverse. Moreover, the structural design of the resonant circuit of this application does not require switching frequency modulation control. Broadband control can achieve wide voltage range output, that is, the switching control frequency can be compressed and narrowed to improve efficiency.

The above descriptions are only preferred embodiments of the present application and are not intended to limit the present application in any form. Those skilled in the art can make various equivalent changes and improvements on the basis of the above embodiments. Any equivalent changes or modifications made within the scope of the claims shall fall within the protection scope of this application.

Claims

A three-phase interleaved wide-range high-efficiency isolated bidirectional converter, characterized in that: the three-phase interleaved wide-range high-efficiency isolated bidirectional converter includes a three-phase bridge switching circuit, a resonant cavity, three transformers and a three-phase bridge rectifier circuit , one side of the three-phase bridge switching circuit and the three-phase bridge rectifier circuit respectively serve as the first connection side and the second connection side of the three-phase interleaved wide-range high-efficiency isolation bidirectional converter, and the resonant cavity includes three resonators. circuit, the three resonant circuits are respectively connected between the midpoints of the three bridge arms of the three-phase bridge switch circuit and the three primary windings of the transformer, wherein,

The resonant circuit includes a first capacitor, a second capacitor, a third capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor is connected to one end of the second inductor, the first capacitor and the third capacitor. , the other ends of the first inductor and the first capacitor are respectively connected to one end of the third inductor and the second capacitor, and the one end of the third inductor is connected to the midpoint of a bridge arm in the three-phase bridge switch circuit, and the third The other ends of the second inductor and the third capacitor are respectively connected to the other ends of the third inductor and the second capacitor, and connected to the primary winding of a transformer, and the ends of the second capacitor and the first capacitor in the three resonant circuits are connected to each other respectively. The connections form a Y-shaped connection. The same-named ends of the three transformer secondary windings correspond to the midpoints of the three bridge arms connected to the three-phase bridge rectifier circuit. The different-named ends of the three transformer secondary windings are connected to each other to form a Y-shaped connection. .
The three-phase interleaved wide-range high-efficiency isolation bidirectional converter according to claim 1, characterized in that: the three-phase bridge switch circuit includes six switch tubes, and each two switch tubes are connected in series to form a bridge arm, and three bridges After the arms are connected in parallel, their two ends serve as the first connection side of the three-phase interleaved wide-range high-efficiency isolation bidirectional converter.
The three-phase interleaved wide-range high-efficiency isolated bidirectional converter according to claim 1, characterized in that: the three-phase bridge rectifier circuit includes six switching tubes, and each two switching tubes are connected in series to form a bridge arm, and three bridges After the arms are connected in parallel, their two ends serve as the second connection side of the three-phase interleaved wide-range high-efficiency isolation bidirectional converter.
The three-phase interleaved wide-range high-efficiency isolation bidirectional converter according to claim 2 or 3, characterized in that: the switching tube is selected from MOSFET, IGBT tube, GaN tube or SiC power tube.
The three-phase interleaved wide-range high-efficiency isolated bidirectional converter according to claim 1, characterized in that: the three-phase interleaved wide-range high-efficiency isolated bidirectional converter further includes a first filter capacitor and a second filter capacitor, and the first Both ends of the filter capacitor are connected to the first connection side of the three-phase interleaved wide range high-efficiency isolation bidirectional converter, and both ends of the second filter capacitor are connected to the second connection side.
A three-phase interleaved wide-range high-efficiency isolated bidirectional converter, characterized in that: the three-phase interleaved wide-range high-efficiency isolated bidirectional converter includes a three-phase bridge switching circuit, a resonant cavity, three transformers and a three-phase bridge rectifier circuit , one side of the three-phase bridge switching circuit and the three-phase bridge rectifier circuit respectively serve as the first connection side and the second connection side of the three-phase interleaved wide-range high-efficiency isolation bidirectional converter, and the resonant cavity includes three resonators. circuit, the three resonant circuits are respectively connected between the midpoints of the three bridge arms of the three-phase bridge switch circuit and the three primary windings of the transformer, wherein,

The resonant circuit includes a first capacitor, a second capacitor, a third capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor is connected to one end of the second inductor, the first capacitor and the third capacitor. , the other ends of the first inductor and the first capacitor are respectively connected to one end of the third inductor and the second capacitor, and the one end of the second capacitor is connected to the midpoint of a bridge arm in the three-phase bridge switch circuit, and the third The other ends of the second inductor and the third capacitor are respectively connected to the other ends of the third inductor and the second capacitor, and connected to the primary winding of a transformer, and one end of the third inductor and the first inductor in the three resonant circuits are connected to each other respectively. The connections form a Y-shaped connection. The same-named ends of the three transformer secondary windings correspond to the midpoints of the three bridge arms connected to the three-phase bridge rectifier circuit. The different-named ends of the three transformer secondary windings are connected to each other to form a Y-shaped connection. .
A three-phase interleaved wide-range high-efficiency isolated bidirectional converter, characterized in that: the three-phase interleaved wide-range high-efficiency isolated bidirectional converter includes a three-phase bridge switching circuit, a resonant cavity, three transformers and a three-phase bridge rectifier circuit , one side of the three-phase bridge switching circuit and the three-phase bridge rectifier circuit respectively serve as the first connection side and the second connection side of the three-phase interleaved wide-range high-efficiency isolation bidirectional converter, and the resonant cavity includes three resonators. circuit, the three resonant circuits are respectively connected between the midpoints of the three bridge arms of the three-phase bridge switch circuit and the three primary windings of the transformer, wherein,

The resonant circuit includes a first capacitor, a second capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor and the second inductor is connected to one end of the first capacitor and the second capacitor. The other end of an inductor is connected to one end of the third inductor and to the midpoint of a bridge arm in the three-phase bridge switch circuit, the other ends of the second inductor and the second capacitor are connected to the primary winding of a transformer, and The other end of the second inductor is connected to the other end of the third inductor. The other ends of the first capacitors in the three resonant circuits are connected to each other to form a Y-shaped connection. The same ends of the three transformer secondary windings are connected to three corresponding ends. The midpoints of the three bridge arms of the phase bridge rectifier circuit and the opposite ends of the three transformer secondary windings are connected to each other to form a Y-shaped connection.
A three-phase interleaved wide-range high-efficiency isolated bidirectional converter, characterized in that: the three-phase interleaved wide-range high-efficiency isolated bidirectional converter includes a three-phase bridge switching circuit, a resonant cavity, three transformers and a three-phase bridge rectifier circuit , one side of the three-phase bridge switching circuit and the three-phase bridge rectifier circuit respectively serve as the first connection side and the second connection side of the three-phase interleaved wide-range high-efficiency isolation bidirectional converter, and the resonant cavity includes three resonators. circuit, the three resonant circuits are respectively connected between the midpoints of the three bridge arms of the three-phase bridge switch circuit and the three primary windings of the transformer, wherein,

The resonant circuit includes a first capacitor, a second capacitor, a first inductor, a second inductor and a third inductor. One end of the first inductor is connected to the first capacitor and one end of the third inductor. One end of the second inductor The other end of the third inductor is connected to one end of the second capacitor. The other end of the first capacitor is connected to the midpoint of one bridge arm in the three-phase bridge switch circuit. The other end of the second inductor is connected to the second capacitor. The primary winding of a transformer, and the other end of the second inductor is connected to the other end of the first inductor, and the same-named ends of the secondary windings of the three transformers are respectively connected to the midpoints of the three bridge arms of the three-phase bridge rectifier circuit, The opposite ends of the primary windings and secondary windings of the three transformers are connected to each other to form a Y-shaped connection.