阅读说明：本技术 单相固态变压器的拓扑结构 (Topological structure of single-phase solid-state transformer ) 是由 王辉 徐铭 粟梅 孙尧 谭凯元 冯江华 陈涛 梁玉 于 2019-11-25 设计创作，主要内容包括：本发明提供了一种单相固态变压器的拓扑结构，包括：交流电源，所述交流电源的正极端与第一电感的第一端电连接；第一H桥电路，所述第一H桥电路的第一端与所述第一电感的第二端电连接；双向DC?DC变换器，所述双向DC?DC变换器的第一端与所述第一H桥电路的第三端电连接；双向buck电路，所述双向buck电路的第一端与所述双向DC?DC变换器的第一端电连接；第二H桥电路，所述第二H桥电路的第一端与所述双向buck电路的第一端电连接。本发明的单相固态变压器的拓扑结构，无中间储能环节，可以减小整个系统的体积，所述第一H桥电路和所述第二H桥电路开关都工作在工频切换状态，减小了开关损耗，并且可以实现功率双向流动。(The invention provides a topological structure of a single-phase solid-state transformer, which comprises: the positive end of the alternating current power supply is electrically connected with the first end of the first inductor; a first end of the first H-bridge circuit is electrically connected with a second end of the first inductor; a first terminal of the bidirectional DC-DC converter is electrically connected with a third terminal of the first H-bridge circuit; a bidirectional buck circuit, a first end of the bidirectional buck circuit being electrically connected to a first end of the bidirectional DC-DC converter; and the first end of the second H-bridge circuit is electrically connected with the first end of the bidirectional buck circuit. The topological structure of the single-phase solid-state transformer has no intermediate energy storage link, the size of the whole system can be reduced, the first H-bridge circuit and the second H-bridge circuit switch work in a power frequency switching state, the switching loss is reduced, and the bidirectional flow of power can be realized.)

1. A topology of a single-phase solid-state transformer, comprising:

the positive end of the alternating current power supply is electrically connected with the first end of the first inductor;

a first end of the first H-bridge circuit is electrically connected with a second end of the first inductor, and a second end of the first H-bridge circuit is electrically connected with a negative electrode end of the alternating current power supply;

a bidirectional DC-DC converter, a first terminal of the bidirectional DC-DC converter being electrically connected with a third terminal of the first H-bridge circuit, a second terminal of the bidirectional DC-DC converter being electrically connected with a fourth terminal of the first H-bridge circuit;

a first end of the bidirectional buck circuit is electrically connected with the first end of the bidirectional DC-DC converter, and a second end of the bidirectional buck circuit is electrically connected with the second end of the bidirectional DC-DC converter;

and the first end of the second H-bridge circuit is electrically connected with the first end of the bidirectional buck circuit, and the second end of the second H-bridge circuit is electrically connected with the second end of the bidirectional buck circuit.

2. The topology of a single-phase solid-state transformer of claim 1, wherein the first H-bridge circuit comprises:

the emitter of the first switch tube is electrically connected with the second end of the first inductor;

a collector of the second switching tube is electrically connected with an emitter of the first switching tube;

a collector electrode of the third switching tube is electrically connected with the collector electrode of the first switching tube;

and the collector electrode of the fourth switching tube is respectively electrically connected with the emitter electrode of the third switching tube and the negative end of the alternating current power supply, and the emitter electrode of the fourth switching tube is electrically connected with the emitter electrode of the second switching tube.

3. The topology of a single-phase solid-state transformer of claim 1, wherein the bidirectional DC-DC converter comprises:

the first end of the primary linear bus capacitor module is electrically connected with the collector of the third switch tube, and the second end of the primary linear bus capacitor module is electrically connected with the emitter of the fourth switch tube;

a first half-bridge circuit, a first end of which is electrically connected with a first end of the primary linear bus capacitor module, and a second end of which is electrically connected with a second end of the primary linear bus capacitor module;

a first end of the LC resonance circuit is electrically connected with a third end of the primary side linear bus capacitor module, and a second end of the LC resonance circuit is electrically connected with a third end of the first half-bridge circuit;

a first end of the high-frequency transformer is electrically connected with a third end of the LC resonance circuit;

and a third H-bridge circuit, wherein the first end of the third H-bridge circuit is electrically connected with the second end of the high-frequency transformer.

4. The topology of a single-phase solid-state transformer of claim 3, wherein the primary linear bus capacitance module comprises:

a first end of the first thin film capacitor is electrically connected with a collector electrode of the third switching tube;

and a first end of the second thin film capacitor is electrically connected with a second end of the first thin film capacitor, and a second end of the second thin film capacitor is electrically connected with an emitter of the fourth switching tube.

5. The topology of a single-phase solid-state transformer of claim 3, wherein the first half-bridge circuit comprises:

a collector of the fifth switching tube is electrically connected with the first end of the first thin film capacitor;

and the collector of the sixth switching tube is electrically connected with the emitter of the fifth switching tube, and the emitter of the sixth switching tube is electrically connected with the second end of the second film capacitor.

6. The topology of a single-phase solid-state transformer of claim 3, wherein the LC resonant circuit comprises:

a first end of the resonant inductor is electrically connected with the collector electrode of the sixth switching tube;

and the first end of the resonant capacitor is electrically connected with the first end of the second thin film capacitor.

7. The topology of a single-phase solid-state transformer of claim 3, wherein the high-frequency transformer comprises:

the first end of the primary winding is electrically connected with the second end of the resonant inductor, and the second end of the primary winding is electrically connected with the second end of the resonant capacitor;

and a first end of the secondary winding is electrically connected with an emitting electrode of the seventh switching tube, and a second end of the secondary winding is electrically connected with an emitting electrode of the ninth switching tube.

8. The topology of the single-phase solid-state transformer of claim 3, wherein the third H-bridge circuit comprises:

a seventh switching tube;

an eighth switching tube, wherein a collector of the eighth switching tube is electrically connected with an emitter of the seventh switching tube;

a ninth switching tube, wherein a collector electrode of the ninth switching tube is electrically connected with a collector electrode of the seventh switching tube;

a tenth switching tube, wherein a collector of the tenth switching tube is electrically connected with an emitter of the ninth switching tube, and an emitter of the tenth switching tube is electrically connected with an emitter of the eighth switching tube;

and a first end of the third thin film capacitor is electrically connected with the collector of the ninth switching tube, and a second end of the third thin film capacitor is electrically connected with the emitter of the tenth switching tube.

9. The topology of a single-phase solid-state transformer of claim 1, wherein the bidirectional buck circuit comprises:

an eleventh switch tube, wherein a collector of the eleventh switch tube is electrically connected to the first end of the third film capacitor;

a twelfth switching tube, wherein a collector of the twelfth switching tube is electrically connected with an emitter of the eleventh switching tube;

a first end of the second inductor is electrically connected with a collector of the twelfth switching tube;

and a first end of the first capacitor is electrically connected with a second end of the second inductor, and a second end of the first capacitor is electrically connected with an emitter of the twelfth switching tube.

10. The topology of a single-phase solid-state transformer of claim 1, wherein the second H-bridge circuit comprises:

a thirteenth switching tube, wherein a collector of the thirteenth switching tube is electrically connected to the second end of the second inductor;

a fourteenth switching tube, a collector of which is electrically connected with an emitter of the thirteenth switching tube;

a fifteenth switching tube, wherein a collector electrode of the fifteenth switching tube is electrically connected with a collector electrode of the fourteenth switching tube;

a sixteenth switching tube, wherein a collector of the sixteenth switching tube is electrically connected with an emitter of the fifteenth switching tube, and an emitter of the sixteenth switching tube is electrically connected with an emitter of the fourteenth switching tube;

a first end of the third inductor is electrically connected with a collector electrode of the fourteenth switching tube;

a first end of the second capacitor is electrically connected with a second end of the third inductor, and a second end of the second capacitor is electrically connected with a collector electrode of the sixteenth switching tube;

and a first end of the first load is electrically connected with a first end of the second capacitor, and a second end of the first load is electrically connected with a second end of the second capacitor.

Technical Field

The invention relates to the technical field of electronic power, in particular to a topological structure of a single-phase solid-state transformer.

Background

The traditional power frequency transformer is not only large in size, but also single in function, along with the rapid development of a smart grid and the grid connection of various distributed energy sources, the function of the traditional power frequency transformer can not meet the requirements of a modern power system, the power electronic transformer, also called as a solid-state transformer, a smart transformer or a flexible transformer, is a novel transformer for realizing the voltage transformation and energy transfer of the power system through a power electronic technology, and has the advantages of small size, light weight, high controllability of primary and secondary side voltage, current and power, a circuit breaker function and no need of a traditional transformer relay protection device.

The existing power electronic transformer has various topological structures, generally including a rectifier stage, an isolation stage and an inverter stage, wherein the isolation stage may adopt an LC resonant converter structure, and in order to adjust output voltage, switching frequency needs to be adjusted, which may affect the implementation of soft switching.

Disclosure of Invention

The invention provides a topological structure of a single-phase solid-state transformer, and aims to solve the problems of large volume and single function of the traditional transformer.

To achieve the above object, an embodiment of the present invention provides a topology of a single-phase solid-state transformer, including:

the positive end of the alternating current power supply is electrically connected with the first end of the first inductor;

a first end of the first H-bridge circuit is electrically connected with a second end of the first inductor, and a second end of the first H-bridge circuit is electrically connected with a negative electrode end of the alternating current power supply;

a bidirectional DC-DC converter, a first terminal of the bidirectional DC-DC converter being electrically connected with a third terminal of the first H-bridge circuit, a second terminal of the bidirectional DC-DC converter being electrically connected with a fourth terminal of the first H-bridge circuit;

a first end of the bidirectional buck circuit is electrically connected with the first end of the bidirectional DC-DC converter, and a second end of the bidirectional buck circuit is electrically connected with the second end of the bidirectional DC-DC converter;

and the first end of the second H-bridge circuit is electrically connected with the first end of the bidirectional buck circuit, and the second end of the second H-bridge circuit is electrically connected with the second end of the bidirectional buck circuit.

Wherein the first H-bridge circuit comprises:

the emitter of the first switch tube is electrically connected with the second end of the first inductor;

a collector of the second switching tube is electrically connected with an emitter of the first switching tube;

a collector electrode of the third switching tube is electrically connected with the collector electrode of the first switching tube;

and the collector electrode of the fourth switching tube is respectively electrically connected with the emitter electrode of the third switching tube and the negative end of the alternating current power supply, and the emitter electrode of the fourth switching tube is electrically connected with the emitter electrode of the second switching tube.

Wherein the bidirectional DC-DC converter includes:

the first end of the primary linear bus capacitor module is electrically connected with the collector of the third switch tube, and the second end of the primary linear bus capacitor module is electrically connected with the emitter of the fourth switch tube;

a first half-bridge circuit, a first end of which is electrically connected with a first end of the primary linear bus capacitor module, and a second end of which is electrically connected with a second end of the primary linear bus capacitor module;

a first end of the LC resonance circuit is electrically connected with a third end of the primary side linear bus capacitor module, and a second end of the LC resonance circuit is electrically connected with a third end of the first half-bridge circuit;

a first end of the high-frequency transformer is electrically connected with a third end of the LC resonance circuit;

and a third H-bridge circuit, wherein the first end of the third H-bridge circuit is electrically connected with the second end of the high-frequency transformer.

Wherein, former limit straight line bus capacitor module includes:

a first end of the first thin film capacitor is electrically connected with a collector electrode of the third switching tube;

and a first end of the second thin film capacitor is electrically connected with a second end of the first thin film capacitor, and a second end of the second thin film capacitor is electrically connected with an emitter of the fourth switching tube.

Wherein the first half-bridge circuit comprises:

a collector of the fifth switching tube is electrically connected with the first end of the first thin film capacitor;

and the collector of the sixth switching tube is electrically connected with the emitter of the fifth switching tube, and the emitter of the sixth switching tube is electrically connected with the second end of the second film capacitor.

Wherein the LC resonance circuit comprises:

a first end of the resonant inductor is electrically connected with the collector electrode of the sixth switching tube;

and the first end of the resonant capacitor is electrically connected with the first end of the second thin film capacitor.

Wherein the high frequency transformer includes:

the first end of the primary winding is electrically connected with the second end of the resonant inductor, and the second end of the primary winding is electrically connected with the second end of the resonant capacitor;

and a first end of the secondary winding is electrically connected with an emitting electrode of the seventh switching tube, and a second end of the secondary winding is electrically connected with an emitting electrode of the ninth switching tube.

Wherein the third H-bridge circuit comprises:

a seventh switching tube;

an eighth switching tube, wherein a collector of the eighth switching tube is electrically connected with an emitter of the seventh switching tube;

a ninth switching tube, wherein a collector electrode of the ninth switching tube is electrically connected with a collector electrode of the seventh switching tube;

a tenth switching tube, wherein a collector of the tenth switching tube is electrically connected with an emitter of the ninth switching tube, and an emitter of the tenth switching tube is electrically connected with an emitter of the eighth switching tube;

and a first end of the third thin film capacitor is electrically connected with the collector of the ninth switching tube, and a second end of the third thin film capacitor is electrically connected with the emitter of the tenth switching tube.

Wherein, two-way buck circuit includes:

an eleventh switch tube, wherein a collector of the eleventh switch tube is electrically connected to the first end of the third film capacitor;

a twelfth switching tube, wherein a collector of the twelfth switching tube is electrically connected with an emitter of the eleventh switching tube;

a first end of the second inductor is electrically connected with a collector of the twelfth switching tube;

and a first end of the first capacitor is electrically connected with a second end of the second inductor, and a second end of the first capacitor is electrically connected with an emitter of the twelfth switching tube.

Wherein the second H-bridge circuit comprises:

a thirteenth switching tube, wherein a collector of the thirteenth switching tube is electrically connected to the second end of the second inductor;

a fourteenth switching tube, a collector of which is electrically connected with an emitter of the thirteenth switching tube;

a fifteenth switching tube, wherein a collector electrode of the fifteenth switching tube is electrically connected with a collector electrode of the fourteenth switching tube;

a sixteenth switching tube, wherein a collector of the sixteenth switching tube is electrically connected with an emitter of the fifteenth switching tube, and an emitter of the sixteenth switching tube is electrically connected with an emitter of the fourteenth switching tube;

a first end of the third inductor is electrically connected with a collector electrode of the fourteenth switching tube;

a first end of the second capacitor is electrically connected with a second end of the third inductor, and a second end of the second capacitor is electrically connected with a collector electrode of the sixteenth switching tube;

and a first end of the first load is electrically connected with a first end of the second capacitor, and a second end of the first load is electrically connected with a second end of the second capacitor.

The scheme of the invention has the following beneficial effects:

the single-phase solid-state transformer topological structure provided by the embodiment of the invention has no intermediate energy storage link, and the direct-current bus capacitor adopts the thin-film capacitor with a small capacitance value, so that the volume of the whole system can be reduced, the reliability of the system can be improved, and the amplitude adjustment of output voltage and the bidirectional flow of power can be realized.

Drawings

FIG. 1 is a schematic circuit diagram illustrating an embodiment of the present invention;

FIG. 2 shows the input voltage and output voltage waveforms of the bidirectional buck circuit according to the present invention;

FIG. 3 illustrates input voltage and output voltage waveforms according to the present invention;

fig. 4 shows waveforms of input current and output current according to the present invention.

[ description of reference ]

1-an alternating current power supply; 2-a first inductance; 3-a first H-bridge circuit; 4-a bidirectional DC-DC converter; 5-a bidirectional buck circuit; 6-a second H-bridge circuit; 7-a first switching tube; 8-a second switching tube; 9-a third switching tube; 10-a fourth switching tube; 11-a first thin film capacitor; 12-a second thin film capacitor; 13-a fifth switching tube; 14-a sixth switching tube; 15-resonant inductance; 16-a resonant capacitance; 17-a primary winding; 18-secondary winding; 19-seventh switching tube; 20-eighth switching tube; 21-ninth switching tube; 22-tenth switching tube; 23-a third thin film capacitor; 24-eleventh switching tube; 25-a twelfth switching tube; 26-a second inductance; 27-a first capacitance; 28-thirteenth switching tube; 29-a fourteenth switching tube; 30-a fifteenth switching tube; 31-sixteenth switching tube; 32-a third inductance; 33-a second capacitance; 34-first load.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

The invention provides a topological structure of a single-phase solid-state transformer, aiming at the problems of large volume and single function of the existing transformer.

As shown in fig. 1 to 4, an embodiment of the present invention provides a topology of a single-phase solid-state transformer, including: the positive end of the alternating current power supply 1 is electrically connected with the first end of the first inductor 2; a first H-bridge circuit 3, a first end of the first H-bridge circuit 3 being electrically connected to a second end of the first inductor 2, a second end of the first H-bridge circuit 3 being electrically connected to a negative terminal of the ac power supply 1; a bidirectional DC-DC converter 4, a first terminal of the bidirectional DC-DC converter 4 being electrically connected to the third terminal of the first H-bridge circuit 3, a second terminal of the bidirectional DC-DC converter 4 being electrically connected to the fourth terminal of the first H-bridge circuit 3; a bidirectional buck circuit 5, wherein a first end of the bidirectional buck circuit 5 is electrically connected with a first end of the bidirectional DC-DC converter 4, and a second end of the bidirectional buck circuit 5 is electrically connected with a second end of the bidirectional DC-DC converter 4; and a second H-bridge circuit 6, wherein a first end of the second H-bridge circuit 6 is electrically connected with a first end of the bidirectional buck circuit 5, and a second end of the second H-bridge circuit 6 is electrically connected with a second end of the bidirectional buck circuit 5.

In the topology structure of the single-phase solid-state transformer according to the above embodiment of the present invention, when the power of the first H-bridge circuit 3 is reversely transmitted: the first H-bridge circuit 3 works in an inverter state, current flows through an IGBT, and a pulsating direct current is converted into a sinusoidal alternating current, and the control method of the first H-bridge circuit 3 is as follows: sampling an input voltage, and conducting the first switch tube 7 and the fourth switch tube 10 when the sampled input voltage is positive; when the sampled input voltage is negative, the second switching tube 8 and the third switching tube 9 are conducted to convert the input sine alternating current into sine half-wave direct current, and when the power is transmitted in the forward direction, the bidirectional DC-DC converter 4: the switching tube of the first half-bridge of the bidirectional DC-DC converter 4 acts at high frequency, the sine half-wave direct current of the primary side direct current bus is converted into high-frequency alternating current with sine envelope curve, the high-frequency alternating current is coupled to the secondary side through the high-frequency transformer, the switching tube in the third H-bridge circuit does not act, and the high-frequency alternating current is converted into sine half-wave direct current through the body diode or the anti-parallel diode of the switching tube without controlled rectification. When the power is transmitted reversely: the switch in the third H-bridge circuit of the bidirectional DC-DC converter 4 operates at a high frequency, and converts a half-wave sine DC of a secondary DC bus into a high-frequency ac whose envelope is sine, and the high-frequency ac is coupled to the primary side by the high-frequency transformer, the switching tube in the first half-bridge does not operate, and the high-frequency ac is converted into a half-wave sine DC by the uncontrolled rectification of the body diode or the anti-parallel diode of the switching tube, and the bidirectional buck circuit 5 performs the double closed-loop feedback control, which specifically comprises: the sampled output voltage is compared with a reference voltage determined according to an input voltage angle obtained by a phase-locked loop to obtain a voltage error signal, then the output quantity of the voltage error signal passing through a voltage outer ring regulator is used as a current reference value of a current inner ring and is compared with the sampled output current to obtain a current error signal, the current error signal is added with the output voltage through the output quantity of the current inner ring regulator and then is divided by a secondary side direct current bus voltage to obtain a modulation signal, the modulation signal is compared with a triangular carrier to obtain a driving signal of the single-phase inverter, and the second H-bridge circuit 6 is used for performing reverse power transmission: the second H-bridge circuit 6 works in a rectifier state, current flows through a diode, an IGBT switching tube operates at power frequency, and an input sinusoidal alternating current is converted into a pulsating direct current, and the control method of the second H-bridge circuit 6 comprises the following steps: sampling the input voltage, and turning on the thirteenth switch tube 28 and the sixteenth switch tube 31 when the sampled input voltage is positive; when the sampled input voltage is negative, the fourteenth switching tube 29 and the fifteenth switching tube 30 are turned on, and the sine half-wave direct current is converted into sine alternating current.

Wherein the first H-bridge circuit 3 includes: a first switch tube 7, an emitter of the first switch tube 7 being electrically connected to the second end of the first inductor 2; a second switch tube 8, wherein the collector of the second switch tube 8 is electrically connected with the emitter of the first switch tube 7; a third switching tube 9, wherein a collector electrode of the third switching tube 9 is electrically connected with a collector electrode of the first switching tube 7; and a collector of the fourth switching tube 10 is electrically connected with an emitter of the third switching tube 9 and a negative end of the alternating current power supply 1, respectively, and an emitter of the fourth switching tube 10 is electrically connected with an emitter of the second switching tube 8.

In the topology structure of the single-phase solid-state transformer according to the above embodiment of the present invention, when power is being transmitted: the first H-bridge circuit 3 works in a rectifier state, current flows through a diode, an IGBT power frequency acts to convert input sine alternating current into pulsating direct current, and a switching tube is an IGBT or MOSFET with an anti-parallel freewheeling diode or other switching devices with the same function.

Wherein the bidirectional DC-DC converter 4 includes: a first end of the primary linear bus capacitor module is electrically connected with a collector of the third switch tube 9, and a second end of the primary linear bus capacitor module is electrically connected with an emitter of the fourth switch tube 10; a first half-bridge circuit, a first end of which is electrically connected with a first end of the primary linear bus capacitor module, and a second end of which is electrically connected with a second end of the primary linear bus capacitor module; a first end of the LC resonance circuit is electrically connected with a third end of the primary side linear bus capacitor module, and a second end of the LC resonance circuit is electrically connected with a third end of the first half-bridge circuit; a first end of the high-frequency transformer is electrically connected with a third end of the LC resonance circuit; and a third H-bridge circuit, wherein the first end of the third H-bridge circuit is electrically connected with the second end of the high-frequency transformer.

Wherein, former limit straight line bus capacitor module includes: a first thin film capacitor 11, wherein a first end of the first thin film capacitor 11 is electrically connected with a collector electrode of the third switching tube 9; a first end of the second thin film capacitor 12 is electrically connected to a second end of the first thin film capacitor 11, and a second end of the second thin film capacitor 12 is electrically connected to an emitter of the fourth switching tube 10.

Wherein the first half-bridge circuit comprises: a fifth switching tube 13, wherein a collector of the fifth switching tube 13 is electrically connected to the first end of the first thin film capacitor 11; a sixth switching tube 14, a collector of the sixth switching tube 14 is electrically connected to the emitter of the fifth switching tube 13, and an emitter of the sixth switching tube 14 is electrically connected to the second end of the second thin film capacitor 12.

Wherein the LC resonance circuit comprises: a resonant inductor 15, wherein a first end of the resonant inductor 15 is electrically connected to the collector of the sixth switching tube 14; a resonant capacitor 16, a first end of the resonant capacitor 16 being electrically connected to a first end of the second thin film capacitor 12.

Wherein the high frequency transformer includes: a primary winding 17, wherein a first end of the primary winding 17 is electrically connected to a second end of the resonant inductor 15, and a second end of the primary winding 17 is electrically connected to a second end of the resonant capacitor 16; and a secondary winding 18, wherein a first end of the secondary winding 18 is electrically connected with the emitter electrode of the seventh switching tube 19, and a second end of the secondary winding 18 is electrically connected with the emitter electrode of the ninth switching tube 21.

Wherein the third H-bridge circuit comprises: a seventh switching tube 19; an eighth switching tube 20, a collector of the eighth switching tube 20 being electrically connected to an emitter of the seventh switching tube 19; a ninth switching tube 21, wherein a collector electrode of the ninth switching tube 21 is electrically connected to a collector electrode of the seventh switching tube 19; a tenth switching tube 22, wherein a collector of the tenth switching tube 22 is electrically connected to an emitter of the ninth switching tube 21, and an emitter of the tenth switching tube 22 is electrically connected to an emitter of the eighth switching tube 20; a third thin film capacitor 23, wherein a first end of the third thin film capacitor 23 is electrically connected to the collector of the ninth switch tube 21, and a second end of the third thin film capacitor 23 is electrically connected to the emitter of the tenth switch tube 22.

In the topology structure of the single-phase solid-state transformer according to the above embodiment of the present invention, the bidirectional DC-DC converter 4 is an LC series resonant converter, the primary side of the converter adopts a half-bridge structure, and the secondary side of the converter adopts a full-bridge structure, so that the voltage reduction function can be realized, the high-frequency transformer can realize electrical isolation of the primary side and the secondary side and adjustment of the voltage amplitude, and the volume of the whole solid-state transformer can be reduced by the high-frequency action of the switching tube of the primary side and the secondary side.

Wherein, the bidirectional buck circuit 5 includes: an eleventh switch tube 24, wherein a collector of the eleventh switch tube 24 is electrically connected to the first end of the third thin film capacitor 23; a twelfth switching tube 25, wherein a collector of the twelfth switching tube 25 is electrically connected to an emitter of the eleventh switching tube 24; a second inductor 26, a first end of the second inductor 26 is electrically connected to the collector of the twelfth switch tube 25; a first capacitor 27, a first end of the first capacitor 27 is electrically connected to the second end of the second inductor 26, and a second end of the first capacitor 27 is electrically connected to the emitter of the twelfth switch tube 25.

In the topology structure of the single-phase solid-state transformer according to the above embodiment of the present invention, the bidirectional buck circuit 5 may adjust the amplitude of the output voltage of the bidirectional DC-DC converter 4.

Wherein the second H-bridge circuit 6 includes: a thirteenth switching tube 28, a collector of the thirteenth switching tube 28 being electrically connected to the second end of the second inductor 26; a fourteenth switching tube 29, a collector of the fourteenth switching tube 29 being electrically connected to an emitter of the thirteenth switching tube 28; a fifteenth switching tube 30, a collector of the fifteenth switching tube 30 being electrically connected to a collector of the fourteenth switching tube 29; a sixteenth switching tube 31, a collector of the sixteenth switching tube 31 is electrically connected to an emitter of the fifteenth switching tube 30, and an emitter of the sixteenth switching tube 31 is electrically connected to an emitter of the fourteenth switching tube 29; a third inductor 32, a first end of the third inductor 32 is electrically connected to the collector of the fourteenth switching tube 29; a second capacitor 33, a first end of the second capacitor 33 is electrically connected to a second end of the third inductor 32, and a second end of the second capacitor 33 is electrically connected to a collector of the sixteenth switching tube 31; a first terminal of the first load 34 is electrically connected to a first terminal of the second capacitor 33, and a second terminal of the first load 34 is electrically connected to a second terminal of the second capacitor 33.

In the topology structure of the single-phase solid-state transformer according to the above embodiment of the present invention, when power is transmitted in the forward direction: the second H-bridge circuit 6 works in an inverter state, and current flows through an IGBT switching tube to convert pulsating direct current into sinusoidal alternating current.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.