Power conversion device

Abstract

This application provides a power conversion device, which includes an AC input terminal, an AC output terminal, a first filter inductor, and an AC / AC circuit. The first filter inductor includes a first inductor winding, a second inductor winding, a third inductor winding, and a first inductor core. The first, second, and third inductor windings are all wound on the first inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device, the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device, and the second ends of the first and second inductor windings are respectively connected to the input terminal of the AC / AC circuit. The first end of the third inductor winding is connected to the first output terminal of the power conversion device, and the second ends of the second and third inductor windings are respectively connected to the output terminal of the AC / AC circuit. Using this application can reduce the circuit cost of the power conversion device.

Description

Technical Field

[0001] This application relates to the field of power supply technology, and in particular to a power conversion device. Background Technology

[0002] AC / AC power supplies, such as uninterruptible power supplies (UPS) and frequency converters, are equipped with input filters and output filters on their AC input and output sides, respectively. These filters filter high-frequency noise from the internal switching circuits, ensuring that the output AC power meets national and industry grid connection standards. Specifically, the input filter reduces electromagnetic interference from the power grid to below required limits, while the output filter ensures that the noise level at the AC / AC power supply output meets the requirements for normal operation of the AC load.

[0003] Currently, both the input and output filters in AC / AC power supplies use filter inductors for filtering. For an example, please refer to [link to example]. Figure 1 The diagram shows the structure of a single-phase input, single-phase output AC / AC power supply. Figure 1 As shown, the AC / AC power supply includes an input filter (i.e., input filter inductor Lin), an output filter (i.e., output filter inductor Lout), and an AC / AC circuit. The input filter inductor Lin includes inductor windings Lin1 and Lin2, and a first magnetic core; both inductor windings Lin1 and Lin2 are wound on the first magnetic core. The output filter inductor Lout includes inductor windings Lout1 and Lout2, and a second magnetic core; both inductor windings Lout1 and Lout2 are wound on the second magnetic core.

[0004] Obviously, the input filter and output filter are two physically separate units, which results in more circuit components and a larger volume for the input and output filters, thus leading to higher circuit costs for AC / AC power supplies. Summary of the Invention

[0005] This application provides a power conversion device that can effectively reduce the circuit cost of power conversion devices.

[0006] In a first aspect, this application provides a power conversion device, which includes an AC input terminal, an AC output terminal, a first filter inductor, and an AC / AC circuit. The first filter inductor includes a first inductor winding, a second inductor winding, a third inductor winding, and a first inductor core. The AC input terminal of the power conversion device includes a first input terminal and a second input terminal, and the AC output terminal of the power conversion device includes a first output terminal and a second output terminal. The first, second, and third inductor windings are all wound on the first inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device, the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device, and the second ends of the first and second inductor windings are respectively connected to the input terminal of the AC / AC circuit. The first end of the third inductor winding is connected to the first output terminal of the power conversion device, and the second ends of the second and third inductor windings are respectively connected to the output terminal of the AC / AC circuit. As can be understood from the circuit structure of the power conversion device in this embodiment, the first filter inductor not only realizes the functions of the input filter inductor Lin and the output filter inductor Lout of the single-phase input and single-phase output AC / AC power supply in the prior art, but also reduces one inductor winding and one inductor core compared to the input filter inductor Lin and the output filter inductor Lout of the single-phase input and single-phase output AC / AC power supply in the prior art, thereby reducing the circuit cost of the power conversion device.

[0007] In conjunction with the first aspect, in a first possible implementation, the power conversion device further includes a second filter inductor, which comprises a fourth inductor winding, a fifth inductor winding, a sixth inductor winding, and a second inductor core. The fourth, fifth, and sixth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device via the fourth inductor winding; the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device via the fifth inductor winding; and the first end of the third inductor winding is connected to the first output terminal of the power conversion device via the sixth inductor winding. As can be understood from the circuit structure of the power conversion device in this embodiment, the first and second filter inductors not only achieve the functions of the two-stage filter inductors at the input and output of a single-phase input, single-phase output AC / AC power supply in the prior art, but also reduce the number of inductor windings and inductor cores by two compared to the two-stage filter inductors at the input and output of a single-phase input, single-phase output AC / AC power supply in the prior art, thereby reducing the circuit cost of the power conversion device.

[0008] In conjunction with the first aspect, in a second possible implementation, the power conversion device further includes a second filter inductor, which comprises a fourth inductor winding, a fifth inductor winding, a sixth inductor winding, a seventh inductor winding, and a second inductor core. The fourth, fifth, sixth, and seventh inductor windings are all wound on the second inductor core. A first end of the first inductor winding is connected to a first input terminal of the power conversion device via the fourth inductor winding. A first end of the second inductor winding is connected to a second input terminal of the power conversion device via the fifth inductor winding, and a first end of the second inductor winding is connected to a second output terminal of the power conversion device via the sixth inductor winding. A first end of the third inductor winding is connected to the first output terminal of the power conversion device via the seventh inductor winding. As can be understood from the circuit structure of the power conversion device in this embodiment, the first and second filter inductors not only achieve the functions of the two-stage filter inductors at the input and output ends of a single-phase input, single-phase output AC / AC power supply in the prior art, but also reduce the number of inductor windings and two inductor cores compared to the two-stage filter inductors at the input and output ends of a single-phase input, single-phase output AC / AC power supply in the prior art, thereby reducing the circuit cost of the power conversion device. Furthermore, besides adopting a circuit structure where the input and output filter inductors share a single inductor winding and a single inductor core, the second filter inductor can also adopt a circuit structure where the input and output filter inductors share a single inductor core. The diverse structures of the second filter inductor result in a variety of power conversion device structures and high flexibility.

[0009] In conjunction with the first aspect, in a third possible implementation, the power conversion device further includes a second filter inductor, which comprises a fourth inductor winding, a fifth inductor winding, and a second inductor core. Both the fourth and fifth inductor windings are wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device via the fourth inductor winding, and the first end of the second inductor winding is connected to the second input terminal of the power conversion device via the fifth inductor winding; alternatively, the first end of the second inductor winding is connected to the second output terminal of the power conversion device via the fourth inductor winding, and the first end of the third inductor winding is connected to the first output terminal of the power conversion device via the fifth inductor winding. It is understood that the power conversion device in this embodiment is applicable to single-phase input and single-phase output applications, where the input terminal is a single-stage inductor filter and the output terminal is a two-stage inductor filter, or vice versa, demonstrating strong applicability.

[0010] In a fourth possible embodiment, combining any of the first to third possible implementations of the first aspect, the input terminal of the AC / AC circuit includes a first input terminal and a common terminal, and the output terminal of the AC / AC circuit includes a first output terminal and a common terminal. Specifically, the second end of the first inductor winding is connected to the first input terminal of the AC / AC circuit, the second end of the second inductor winding is connected to the common terminal of the AC / AC circuit, and the second end of the third inductor winding is connected to the first output terminal of the AC / AC circuit. It is understood that the AC / AC circuit in this embodiment can be any single-phase input, single-phase output AC / AC circuit, suitable for power conversion devices with single-phase input and single-phase output.

[0011] In conjunction with the fourth possible implementation of the first aspect, in the fifth possible implementation, the AC / AC circuit includes a first phase bridge arm, a second phase bridge arm, a third phase bridge arm, a first bus capacitor, a first inductor, and a second inductor. The first phase bridge arm, the second phase bridge arm, the third phase bridge arm, and the first bus capacitor are connected in parallel. The midpoint of the first phase bridge arm is connected to the first input terminal of the AC / AC circuit through the first inductor; the midpoint of the second phase bridge arm is connected to the common terminal of the AC / AC circuit; and the midpoint of the third phase bridge arm is connected to the first output terminal of the AC / AC circuit.

[0012] In conjunction with the fourth possible implementation of the first aspect, in the sixth possible implementation, the AC / AC circuit includes a first phase bridge arm, a second phase bridge arm, a first bus capacitor, a second bus capacitor, a first inductor, a second inductor, a first switch, a second switch, a third switch, and a fourth switch. The first and second bus capacitors are connected in series and then in parallel to the two ends of the first phase bridge arm. The first and second phase bridge arms are connected in parallel, and the series connection point of the first and second bus capacitors is connected to the common terminal of the AC / AC circuit. The first and second switches are connected in reverse series between the common terminal of the AC / AC circuit and the midpoint of the first phase bridge arm. The third and fourth switches are also connected in reverse series between the common terminal of the AC / AC circuit and the midpoint of the second phase bridge arm. The midpoint of the first phase bridge arm is connected to the first input terminal of the AC / AC circuit through the first inductor, and the midpoint of the second phase bridge arm is connected to the first output terminal of the AC / AC circuit through the second inductor. It is understood that, in addition to the three-bridge-arm converter circuit in the previous embodiment, the AC / AC circuit provided in this application can also adopt the circuit structure of the AC / AC circuit provided in this embodiment. The AC / AC circuit has a variety of structures, which makes the power conversion device have a variety of structures and high flexibility.

[0013] In conjunction with the first aspect, in the seventh possible implementation, the first filter inductor further includes a fourth inductor winding and a fifth inductor winding, and the AC output terminal of the power conversion device further includes a third output terminal and a fourth output terminal. Both the fourth and fifth inductor windings are wound on the first inductor core. The first end of the fourth inductor winding is connected to the third output terminal of the power conversion device, the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device, and the second ends of the fourth and fifth inductor windings are respectively connected to the output terminals of the AC / AC circuit. It is understood that, based on the circuit structure of the power conversion device in this embodiment, the first filter inductor not only performs the functions of the input filter inductor and output filter inductor in a single-phase input, three-phase output AC / AC power supply in the prior art, but also, compared to the input filter inductor and output filter inductor in a single-phase input, three-phase output AC / AC power supply in the prior art, the first filter inductor reduces one inductor winding and one inductor core, thereby reducing the circuit cost of the power conversion device.

[0014] In conjunction with the seventh possible implementation of the first aspect, in the eighth possible implementation, the power conversion device further includes a second filter inductor, which comprises a sixth inductor winding, a seventh inductor winding, an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, and a second inductor core. The sixth, seventh, eighth, ninth, and tenth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device via the sixth inductor winding; the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device via the seventh inductor winding; the first end of the third inductor winding is connected to the first output terminal of the power conversion device via the eighth inductor winding; the first end of the fourth inductor winding is connected to the third output terminal of the power conversion device via the ninth inductor winding; and the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device via the tenth inductor winding. It is understandable that, based on the circuit structure of the power conversion device in this embodiment, the first and second filter inductors reduce two inductor windings and two inductor cores compared to the two-stage filter inductors at the input and output of a single-phase input, three-phase output AC / AC power supply in the prior art, thereby reducing the circuit cost of the power conversion device.

[0015] In conjunction with the seventh possible implementation of the first aspect, in the ninth possible implementation, the power conversion device further includes a second filter inductor, which comprises a sixth inductor winding, a seventh inductor winding, an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, an eleventh inductor winding, and a second inductor core. The sixth, seventh, eighth, ninth, tenth, and eleventh inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the sixth inductor winding; the first end of the second inductor winding is connected to the second input terminal of the power conversion device through the seventh inductor winding; and the first end of the second inductor winding is connected to the second output terminal of the power conversion device through the eighth inductor winding. The first end of the third inductor winding is connected to the first output terminal of the power conversion device through the ninth inductor winding; the first end of the fourth inductor winding is connected to the third output terminal of the power conversion device through the tenth inductor winding; and the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device through the eleventh inductor winding. As can be understood from the circuit structure of the power conversion device in this embodiment, compared to the two-stage input and two-stage output filter inductors of a single-phase input, three-phase output AC / AC power supply in the prior art, the first and second filter inductors reduce one inductor winding and two inductor cores, thereby reducing the circuit cost of the power conversion device. Furthermore, besides adopting a circuit structure where the input and output filter inductors share a single inductor winding and core, the second filter inductor can also adopt a circuit structure where both the input and output filter inductors share a single inductor core. This versatility in structure allows for diverse power conversion device structures and high flexibility.

[0016] In a tenth possible embodiment, combining any of the seventh to ninth possible embodiments of the first aspect, the input terminal of the AC / AC circuit includes a first input terminal and a common terminal, and the output terminal of the AC / AC circuit includes a first output terminal, a second output terminal, a third output terminal, and a common terminal. Specifically, the second end of the first inductor winding is connected to the first input terminal of the AC / AC circuit, and the second end of the second inductor winding is connected to the common terminal of the AC / AC circuit. The second end of the third inductor winding is connected to the first output terminal of the AC / AC circuit, the second end of the fourth inductor winding is connected to the second output terminal of the AC / AC circuit, and the second end of the fifth inductor winding is connected to the third output terminal of the AC / AC circuit. It is understood that the AC / AC circuit in this embodiment can be any AC / AC circuit with single-phase input and three-phase output, suitable for power conversion devices with single-phase input and three-phase output.

[0017] In conjunction with the tenth possible implementation of the first aspect, in the eleventh possible implementation, the AC / AC circuit includes a first phase bridge arm, a second phase bridge arm, a third phase bridge arm, a fourth phase bridge arm, a first bus capacitor, a second bus capacitor, a first inductor, a second inductor, a third inductor, and a fourth inductor. The first, second, third, and fourth phase bridge arms are connected in parallel. The first and second bus capacitors are connected in series and then in parallel across the two ends of the first phase bridge arm, with their connection point connected to a common terminal. The midpoint of the first phase bridge arm is connected to the first input terminal of the AC / AC circuit via the first inductor. The midpoint of the second phase bridge arm is connected to the first output terminal of the AC / AC circuit via the second inductor; the midpoint of the third phase bridge arm is connected to the second output terminal of the AC / AC circuit via the third inductor; and the midpoint of the fourth phase bridge arm is connected to the third output terminal of the AC / AC circuit via the fourth inductor.

[0018] In conjunction with the first aspect, in the twelfth possible embodiment, the first filter inductor further includes a fourth inductor winding and a fifth inductor winding, and the AC input terminal of the power conversion device further includes a third input terminal and a fourth input terminal. Both the fourth and fifth inductor windings are wound on the first inductor core. The first end of the fourth inductor winding is connected to the third input terminal of the power conversion device, the first end of the fifth inductor winding is connected to the fourth input terminal of the power conversion device, and the second ends of the fourth and fifth inductor windings are respectively connected to the input terminals of the AC / AC circuit. It is understood that, based on the circuit structure of the power conversion device in this embodiment, the first filter inductor not only performs the functions of the input filter inductor and output filter inductor in a three-phase input, single-phase output AC / AC power supply in the prior art, but also, compared to the input filter inductor and output filter inductor in a three-phase input, single-phase output AC / AC power supply in the prior art, the first filter inductor reduces one inductor winding and one inductor core, thereby reducing the circuit cost of the power conversion device.

[0019] In conjunction with the twelfth possible implementation of the first aspect, in the thirteenth possible implementation, the power conversion device further includes a second filter inductor, which comprises a sixth inductor winding, a seventh inductor winding, an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, and a second inductor core. The sixth, seventh, eighth, ninth, and tenth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device via the sixth inductor winding; the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device via the seventh inductor winding; the first end of the third inductor winding is connected to the first output terminal of the power conversion device via the eighth inductor winding; the first end of the fourth inductor winding is connected to the third input terminal of the power conversion device via the ninth inductor winding; and the first end of the fifth inductor winding is connected to the fourth input terminal of the power conversion device via the tenth inductor winding. It is understandable that, based on the circuit structure of the power conversion device in this embodiment, the first and second filter inductors reduce two inductor windings and two inductor cores compared to the two-stage filter inductors at the input and output of a three-phase input, single-phase output AC / AC power supply in the prior art, thereby reducing the circuit cost of the power conversion device.

[0020] In conjunction with the twelfth possible implementation of the first aspect, in the fourteenth possible implementation, the power conversion device further includes a second filter inductor, which comprises a sixth inductor winding, a seventh inductor winding, an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, an eleventh inductor winding, and a second inductor core. The sixth, seventh, eighth, ninth, and tenth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the sixth inductor winding; the first end of the second inductor winding is connected to the second input terminal of the power conversion device through the seventh inductor winding; the first end of the second inductor winding is connected to the second output terminal of the power conversion device through the eighth inductor winding; the first end of the third inductor winding is connected to the first output terminal of the power conversion device through the ninth inductor winding; the first end of the fourth inductor winding is connected to the third input terminal of the power conversion device through the tenth inductor winding; and the first end of the fifth inductor winding is connected to the fourth input terminal of the power conversion device through the eleventh inductor winding. As can be understood from the circuit structure of the power conversion device in this embodiment, compared to the two-stage input and two-stage output filter inductors of a three-phase input, single-phase output AC / AC power supply in the prior art, the first and second filter inductors reduce one inductor winding and two inductor cores, thereby reducing the circuit cost of the power conversion device. Furthermore, besides adopting a circuit structure where the input and output filter inductors share a single inductor winding and core, the second filter inductor can also adopt a circuit structure where both the input and output filter inductors share a single inductor core. This versatility in structure allows for diverse power conversion device structures and high flexibility.

[0021] In conjunction with any one of the twelfth to fourteenth possible embodiments of the first aspect, in the fifteenth possible embodiment, the input terminals of the AC / AC circuit include a first input terminal, a second input terminal, a third input terminal, and a common terminal, and the output terminals of the AC / AC circuit include a first output terminal and a common terminal. Specifically, the second end of the first inductor winding is connected to the first input terminal of the AC / AC circuit, the second end of the fourth inductor winding is connected to the second input terminal of the AC / AC circuit, and the second end of the fifth inductor winding is connected to the third input terminal of the AC / AC circuit. The second end of the second inductor winding is connected to the common terminal of the AC / AC circuit, and the second end of the third inductor winding is connected to the first output terminal of the AC / AC circuit. It is understood that the AC / AC circuit in this embodiment can be any AC / AC circuit with three-phase input and single-phase output, suitable for power conversion devices with three-phase input and single-phase output.

[0022] In conjunction with the fifteenth possible implementation of the first aspect, in the sixteenth possible implementation, the AC / AC circuit includes a first phase bridge arm, a second phase bridge arm, a third phase bridge arm, a fourth phase bridge arm, a first bus capacitor, a second bus capacitor, a first inductor, a second inductor, a third inductor, and a fourth inductor. The first, second, third, and fourth phase bridge arms are connected in parallel. The first and second bus capacitors are connected in series and then in parallel across the two ends of the first phase bridge arm, with the series connection point of the first and second bus capacitors connected to a common terminal. The midpoint of the first phase bridge arm is connected to the first input terminal of the AC / AC circuit through the first inductor; the midpoint of the second phase bridge arm is connected to the second input terminal of the AC / AC circuit through the second inductor; and the midpoint of the third phase bridge arm is connected to the third input terminal of the AC / AC circuit through the third inductor. The midpoint of the fourth phase bridge arm is connected to the first output terminal of the AC / AC circuit through the fourth inductor.

[0023] In conjunction with the first aspect, in the seventeenth possible implementation, the first filter inductor further includes a fourth inductor winding, a fifth inductor winding, a sixth inductor winding, and a seventh inductor winding; the AC input terminal of the power conversion device further includes a third input terminal and a fourth input terminal; and the AC output terminal of the power conversion device further includes a third output terminal and a fourth output terminal. The fourth, fifth, sixth, and seventh inductor windings are all wound on the first inductor core. The first end of the fourth inductor winding is connected to the third output terminal of the power conversion device, the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device, and the second ends of the fourth and fifth inductor windings are respectively connected to the output terminals of the AC / AC circuit. The first end of the sixth inductor winding is connected to the third input terminal of the power conversion device, the first end of the seventh inductor winding is connected to the fourth input terminal of the power conversion device, and the second ends of the sixth and seventh inductor windings are respectively connected to the input terminals of the AC / AC circuit. As can be understood from the circuit structure of the power conversion device in this embodiment, the first filter inductor can not only realize the functions of the input filter inductor and output filter inductor in the existing three-phase input and three-phase output AC / AC power supply, but also, compared with the input filter inductor and output filter inductor in the existing three-phase input and three-phase output AC / AC power supply, the first filter inductor reduces one inductor winding and one inductor core, thereby reducing the circuit cost of the power conversion device.

[0024] In conjunction with the seventeenth possible implementation of the first aspect, in the eighteenth possible implementation, the power conversion device further includes a second filter inductor, which comprises an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, an eleventh inductor winding, a twelfth inductor winding, a thirteenth inductor winding, a fourteenth inductor winding, and a second inductor core. The eighth, ninth, tenth, eleventh, twelfth, thirteenth, and fourteenth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the eighth inductor winding; the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device through the ninth inductor winding; and the first end of the third inductor winding is connected to the first output terminal of the power conversion device through the tenth inductor winding. The first end of the fourth inductor winding is connected to the third output terminal of the power conversion device through the eleventh inductor winding, and the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device through the twelfth inductor winding. The first end of the sixth inductor winding is connected to the third input terminal of the power conversion device through the thirteenth inductor winding, and the first end of the seventh inductor winding is connected to the fourth input terminal of the power conversion device through the fourteenth inductor winding. It can be understood that, based on the circuit structure of the power conversion device in this embodiment, compared to the two-stage filter inductors at the input and output of a three-phase input, three-phase output AC / AC power supply in the prior art, the first and second filter inductors reduce two inductor windings and two inductor cores, thereby reducing the circuit cost of the power conversion device.

[0025] In conjunction with the seventeenth possible implementation of the first aspect, in the nineteenth possible implementation, the power conversion device further includes a second filter inductor, which comprises an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, an eleventh inductor winding, a twelfth inductor winding, a thirteenth inductor winding, a fourteenth inductor winding, a fifteenth inductor winding, and a second inductor core. The eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, and fifteenth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the eighth inductor winding; the first end of the second inductor winding is connected to the second input terminal of the power conversion device through the ninth inductor winding; and the first end of the second inductor winding is connected to the second output terminal of the power conversion device through the tenth inductor winding. The first end of the third inductor winding is connected to the first output terminal of the power conversion device through the eleventh inductor winding. The first end of the fourth inductor winding is connected to the third output terminal of the power conversion device through the twelfth inductor winding. The first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device through the thirteenth inductor winding. The first end of the sixth inductor winding is connected to the third input terminal of the power conversion device through the fourteenth inductor winding. The first end of the seventh inductor winding is connected to the fourth input terminal of the power conversion device through the fifteenth inductor winding. It can be understood that, based on the circuit structure of the power conversion device in this embodiment, compared to the two-stage filter inductors at the input and output terminals of a three-phase input, three-phase output AC / AC power supply in the prior art, the first and second filter inductors reduce one inductor winding and two inductor cores, thereby reducing the circuit cost of the power conversion device. In addition to adopting a circuit structure in which the input and output filter inductors share a single inductor winding and a single inductor core, the second filter inductor can also adopt a circuit structure in which the input and output filter inductors share a single inductor core. The diverse structures of the second filter inductor make the power conversion equipment more versatile and flexible.

[0026] In conjunction with any of the seventeenth to nineteenth possible embodiments of the first aspect, in the twentieth possible embodiment, the input terminals of the AC / AC circuit include a first input terminal, a second input terminal, a third input terminal, and a common terminal, and the output terminals of the AC / AC circuit include a first output terminal, a second output terminal, a third output terminal, and a common terminal. Specifically, the second end of the first inductor winding is connected to the first input terminal of the AC / AC circuit, the second end of the sixth inductor winding is connected to the second input terminal of the AC / AC circuit, the second end of the seventh inductor winding is connected to the third input terminal of the AC / AC circuit, and the second end of the second inductor winding is connected to the common terminal of the AC / AC circuit. The second end of the third inductor winding is connected to the first output terminal of the AC / AC circuit, the second end of the fourth inductor winding is connected to the second output terminal of the AC / AC circuit, and the second end of the fifth inductor winding is connected to the third output terminal of the AC / AC circuit. It is understood that the AC / AC circuit in this embodiment can be any three-phase input, three-phase output AC / AC circuit, suitable for three-phase input, three-phase output power conversion devices.

[0027] In conjunction with the twentieth possible implementation of the first aspect, in the twenty-first possible implementation, the AC / AC circuit includes a first phase bridge arm, a second phase bridge arm, a third phase bridge arm, a fourth phase bridge arm, a fifth phase bridge arm, a sixth phase bridge arm, a first bus capacitor, a second bus capacitor, a first inductor, a second inductor, a third inductor, a fourth inductor, a fifth inductor, and a sixth inductor. The first phase bridge arm, second phase bridge arm, third phase bridge arm, fourth phase bridge arm, fifth phase bridge arm, and sixth phase bridge arm are connected in parallel. The first bus capacitor and the second bus capacitor are connected in series and then in parallel across the two ends of the first phase bridge arm; the series connection point of the first bus capacitor and the second bus capacitor is connected to a common terminal. The midpoint of the first phase bridge arm is connected to the first input terminal of the AC / AC circuit through the first inductor; the midpoint of the second phase bridge arm is connected to the second input terminal of the AC / AC circuit through the second inductor; and the midpoint of the third phase bridge arm is connected to the third input terminal of the AC / AC circuit through the third inductor. The midpoint of the fourth phase bridge arm is connected to the first output terminal of the AC / AC circuit through the fourth inductor; the midpoint of the fifth phase bridge arm is connected to the second output terminal of the AC / AC circuit through the fifth inductor; and the midpoint of the sixth phase bridge arm is connected to the third output terminal of the AC / AC circuit through the sixth inductor.

[0028] In conjunction with any of the first to the sixteenth possible embodiments of the first aspect, in the twenty-second possible embodiment, the power conversion device further includes a first filter capacitor. The first filter capacitor is connected between the first input terminal and the first output terminal of the power conversion device, or connected between the second terminal of the first inductor winding and the second terminal of the third inductor winding. It is understood that the first filter capacitor, connected across the connection line where the input terminal of the power conversion device is located and the connection line where the output terminal is located, offers various placement options and high flexibility.

[0029] In conjunction with the second, third, ninth, or fourteenth possible implementations of the first aspect, in the twenty-third possible implementation, the power conversion device further includes a first filter capacitor connected between the second input terminal and the second output terminal of the power conversion device.

[0030] In conjunction with any of the seventeenth to twenty-first possible embodiments of the first aspect, in the twenty-fourth possible embodiment, the power conversion device further includes a first filter capacitor connected between a first input terminal and a first output terminal of the power conversion device, or connected between a third input terminal and a third output terminal of the power conversion device, or connected between a fourth input terminal and a fourth output terminal of the power conversion device, or connected between a second end of a first inductor winding and a second end of a third inductor winding, or connected between a second end of a sixth inductor winding and a second end of a fourth inductor winding, or connected between a second end of a seventh inductor winding and a second end of a fifth inductor winding.

[0031] In conjunction with the nineteenth possible implementation of the first aspect, in the twenty-fifth possible implementation, the power conversion device further includes a first filter capacitor connected between the second input terminal and the second output terminal of the power conversion device.

[0032] In conjunction with any one of the first aspect to the twenty-fifth possible implementation of the first aspect, in the twenty-sixth possible implementation, the power conversion device is an uninterruptible power supply.

[0033] In conjunction with any of the first to twenty-fifth possible embodiments of the first aspect, in the twenty-seventh possible embodiment, the power conversion device is an inverter. The input terminal of the AC / AC circuit is a bidirectional input / output terminal of the AC / AC circuit. The inverter also includes a first DC input terminal and a DC / DC circuit. The AC / AC circuit includes both an AC / DC circuit and a DC / AC circuit. The first DC input terminal of the inverter is used to connect to a photovoltaic string. The AC terminal of the AC / DC circuit serves as a bidirectional input / output terminal of the AC / AC circuit, and the DC terminal of the AC / DC circuit connects to the DC input terminal and the DC output terminal of the DC / AC circuit. The AC output terminal of the DC / AC circuit serves as the output terminal of the AC / AC circuit, and the DC input terminal of the DC / DC circuit connects to the first DC input terminal of the inverter. It is understood that the power conversion device can be an uninterruptible power supply or an inverter, offering diverse product forms and high flexibility. Attached Figure Description

[0034] Figure 1This is a schematic diagram of the structure of an AC / AC power supply provided by existing technology;

[0035] Figure 2 This is a schematic diagram illustrating the application scenario of the power conversion device provided in this application;

[0036] Figure 3a This is a schematic diagram of the power conversion device provided in this application;

[0037] Figure 3b This is another structural schematic diagram of the power conversion device provided in this application;

[0038] Figure 3c This is another structural schematic diagram of the power conversion device provided in this application;

[0039] Figure 4a This is another structural schematic diagram of the power conversion device provided in this application;

[0040] Figure 4b This is another structural schematic diagram of the power conversion device provided in this application;

[0041] Figure 4c This is another structural schematic diagram of the power conversion device provided in this application;

[0042] Figure 4d This is another structural schematic diagram of the power conversion device provided in this application;

[0043] Figure 5a This is another structural schematic diagram of the power conversion device provided in this application;

[0044] Figure 5b This is another structural schematic diagram of the power conversion device provided in this application;

[0045] Figure 5c This is another structural schematic diagram of the power conversion device provided in this application;

[0046] Figure 5d This is another structural schematic diagram of the power conversion device provided in this application;

[0047] Figure 6a This is another structural schematic diagram of the power conversion device provided in this application;

[0048] Figure 6b This is another structural schematic diagram of the power conversion device provided in this application;

[0049] Figure 6c This is another structural schematic diagram of the power conversion device provided in this application;

[0050] Figure 6d This is another structural schematic diagram of the power conversion device provided in this application;

[0051] Figure 7a This is another structural schematic diagram of the power conversion device provided in this application;

[0052] Figure 7b This is another structural schematic diagram of the power conversion device provided in this application;

[0053] Figure 7c This is another structural schematic diagram of the power conversion device provided in this application;

[0054] Figure 7d This is another structural schematic diagram of the power conversion device provided in this application;

[0055] Figure 8 This is another structural schematic diagram of the power conversion device provided in this application. Detailed Implementation

[0056] The power conversion equipment provided in this application is applicable to various fields, including new energy smart microgrids, power transmission and distribution, new energy (such as photovoltaic grid-connected fields and wind power grid-connected fields), photovoltaic power generation, energy storage power generation, and wind power generation. The power conversion equipment provided in this application can be AC / AC power supplies such as UPS, inverters, frequency converters, and fixed-frequency power supplies, suitable for different application scenarios, such as photovoltaic power supply scenarios (including large-scale photovoltaic power plant scenarios, small and medium-sized distributed photovoltaic power plant scenarios, and residential photovoltaic system scenarios), energy storage power supply scenarios (including large-scale energy storage power plant scenarios, small and medium-sized distributed energy storage power plant scenarios, and residential photovoltaic-energy storage power generation system scenarios), and UPS power supply scenarios. The following explanation uses the UPS power supply scenario as an example.

[0057] See Figure 2 , Figure 2 This is a schematic diagram illustrating an application scenario of the power conversion device provided in this application. In a UPS power supply scenario, the power conversion device provided in this application can... Figure 2The UPS shown has its AC input connected to the AC power grid and its AC output connected to AC household appliances. The UPS includes a first filter inductor L1 and an AC / AC circuit. The first filter inductor L1 includes a first inductor winding L11, a second inductor winding L12, a third inductor winding L13, and a first inductor core (not shown). The UPS's AC input includes a first input terminal in1 and a second input terminal in2, and the UPS's output includes a first output terminal out1 and a second output terminal out2. The first inductor winding L11, the second inductor winding L12, and the third inductor winding L13 are all wound on the first inductor core. The first end of the first inductor winding L11 and the first end of the second inductor winding L12 are respectively connected to the first input terminal in1 and the second input terminal in2 of the UPS. The second end of the first inductor winding L11 and the second end of the second inductor winding L12 are respectively connected to the input terminals in11 and in / out of the AC / AC circuit. The first end of the second inductor winding L12 and the first end of the third inductor winding L13 are respectively connected to the second output terminal out2 and the first output terminal out1 of the UPS. The second end of the second inductor winding L12 and the second end of the third inductor winding L13 are respectively connected to the output terminals in / out and out11 of the AC / AC circuit.

[0058] Optionally, the UPS may also include an energy storage unit (such as a battery). When the AC mains no longer outputs AC power, the UPS can use the DC / AC circuit in the AC / AC circuit to invert the DC power output from the energy storage unit into AC power to achieve uninterrupted power supply to AC loads.

[0059] Optionally, the UPS may also include a bypass switch, which can be located between the first input terminal in1 and the first output terminal out1 of the UPS, or between the first input terminal in11 and the first output terminal out11 of the AC / AC circuit. The bypass switch can be a controllable switch such as a relay or a silicon controlled rectifier (SCR). When the AC / AC circuit in the UPS fails, the UPS can control the bypass switch to close, allowing AC power from the mains to be directly output to the AC load, thus improving both the stability and efficiency of the UPS.

[0060] After the UPS starts working, the first inductor winding L11 and the second inductor winding L12 in the first filter inductor L1 filter the AC power input from the AC mains to ensure that the electromagnetic interference (EMI) of the AC power input is below the required limit. The AC power with EMI below the required limit is then output to the input terminal of the AC / AC circuit. The AC / AC circuit first rectifies and then inverts the AC power input to its terminal into AC power that conforms to the operating voltage of the AC load (such as AC household appliances), and outputs it to the second inductor winding L12 and the third inductor winding L13. The second inductor winding L12 and the third inductor winding L13 filter the AC power output from the AC / AC circuit to ensure that the noise level of the AC power output to the AC load meets the requirements for normal operation of the AC load, thereby achieving power supply to the AC load.

[0061] As can be seen from the circuit structure of the UPS described above, the second inductor winding L12 can serve as both an input and output inductor winding. In other words, the second inductor winding L12 is a shared filter inductor winding for both the input and output filter inductors of the UPS. Furthermore, since the first filter inductor only includes the first inductor core, the first filter inductor L1 not only fulfills the functions of the input filter inductor Lin and output filter inductor Lout in a single-phase input, single-phase output AC / AC power supply in the prior art, but also reduces the number of inductor windings and inductor cores compared to the input filter inductor Lin and output filter inductor Lout in a single-phase input, single-phase output AC / AC power supply in the prior art. This reduces the size of the UPS and lowers its circuit cost. The above is merely an example of the application scenarios of the power conversion device provided in this application, and is not exhaustive. This application does not limit the application scenarios.

[0062] The following example uses a power conversion device connected to an AC power grid at its AC input and to an AC load at its AC output. Figures 3a to 8 The working principle of the power conversion device provided in this application is illustrated by example.

[0063] See Figure 3a , Figure 3a This is a structural schematic diagram of the power conversion device provided in this application. For example... Figure 3aAs shown, the AC input terminal of the power conversion device 1 is used to connect to the AC power grid, and the AC output terminal is used to connect to the AC load. The AC input terminal of the power conversion device 1 includes a first input terminal in1 and a second input terminal in2, and the AC output terminal of the power conversion device 1 includes a first output terminal out1 and a second output terminal out2. Specifically, the first input terminal in1 and the second input terminal in2 of the power conversion device 1 are connected to the AC power grid, and the first output terminal out1 and the second output terminal out2 of the power conversion device are connected to the AC load. The power conversion device 1 includes a first filter inductor L1 and an AC / AC circuit 11. The first filter inductor L1 includes a first inductor winding L11, a second inductor winding L12, a third inductor winding L13, and a first inductor core.

[0064] The first inductor winding L11, the second inductor winding L12, and the third inductor winding L13 are all wound on the first inductor core. The first ends of the first and second inductor windings are respectively connected to the first input terminal in1 and the second input terminal in2 of the power conversion device 1. The second ends of the first inductor winding L11 and the second inductor winding L12 are respectively connected to the input terminals of the AC / AC circuit 11. Specifically, the input terminals of the AC / AC circuit 11 include a first input terminal in11 and a common terminal in / out. The second ends of the first inductor winding L11 and the second inductor winding L12 are respectively connected to the first input terminal in11 and the common terminal in / out of the AC / AC circuit 11.

[0065] The first ends of the second inductor winding L12 and the third inductor winding L13 are respectively connected to the second output terminal out2 and the first output terminal out1 of the power conversion device 1. The second ends of the second inductor winding L12 and the third inductor winding L13 are respectively connected to the output terminals of the AC / AC circuit 11. Specifically, the output terminals of the AC / AC circuit 11 include the first output terminal out11 and a common terminal in / out. The second ends of the second inductor winding L12 and the third inductor winding L13 are respectively connected to the common terminal in / out and the first output terminal out11 of the AC / AC circuit 11.

[0066] based on Figure 3aAs shown in the circuit structure and energy flow of the power conversion device 1, when AC power from the AC grid is input into the power conversion device 1, the first inductor winding L11 and the second inductor winding L12 can filter the AC power input from the AC grid to reduce electromagnetic interference. Then, the AC power output from the AC / AC circuit 11 is filtered by the second inductor winding L12 and the third inductor winding L3 to obtain AC power that meets the normal operating noise requirements of the AC load. Clearly, the first filtering inductor L1 can achieve the functions of the input filtering inductor Lin and the output filtering inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art.

[0067] In this embodiment, the first filter inductor L1 not only performs the functions of the input filter inductor Lin and the output filter inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art, but also reduces one inductor winding and one inductor core compared to the input filter inductor Lin and the output filter inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art. This reduces the size of the power conversion device 1 and lowers the circuit cost of the power conversion device 1.

[0068] See Figure 3b , Figure 3b This is another structural schematic diagram of the power conversion device provided in this application. For example... Figure 3bAs shown, the power conversion device 1 includes a first filter inductor L1, a first filter capacitor C1, and an AC / AC circuit 11. The AC / AC circuit 11 includes a first phase bridge arm 111, a second phase bridge arm 112, a third phase bridge arm 113, a first bus capacitor Cbus1, a first inductor Lin1, and a second inductor Lout1. The first phase bridge arm 111, the second phase bridge arm 112, the third phase bridge arm 113, and the first bus capacitor Cbus1 are connected in parallel. Specifically, switching transistors Q11 and Q12 are connected in series to form the first phase bridge arm 111, switching transistors Q21 and Q22 are connected in series to form the second phase bridge arm 112, and switching transistors Q31 and Q32 are connected in series to form the third phase bridge arm 113. The midpoint a1 of the first phase bridge arm 111, i.e., the connection point of the series connection between switching transistors Q11 and Q12, is connected to the first input terminal in11 of the AC / AC circuit 11 through the first inductor Lin1. The midpoint a2 of the second phase bridge arm 112, i.e., the series connection of switching transistors Q21 and Q22, is connected to the common terminal in / out of the AC / AC circuit 11. The midpoint a3 of the third phase bridge arm 113, i.e., the series connection of switching transistors Q31 and Q32, is connected to the first output terminal out11 of the AC / AC circuit 11. The switching transistors in the above three-phase bridge arms can be diodes, metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), or gallium nitride (GaN) transistors, etc., and this application does not impose any restrictions on this. In addition, the first input terminal in1 of the power conversion device 1 is connected to any one of the three-phase AC terminals of the AC power grid, and the second input terminal in2 of the power conversion device 1 is connected to the neutral terminal of the AC power grid.

[0069] The first filter capacitor C1 is connected between the first input terminal in1 and the first output terminal out1 of the power conversion device 1. When the capacitance value of the first filter capacitor C1 is equal to the sum of the capacitance values ​​of the input filter capacitor Cin and the output filter capacitor Cout in the prior art, the first filter capacitor C1 can replace the input filter capacitor Cin and the output filter capacitor Cout in the prior art, making the positions of the filter capacitors in the power conversion device 1 more concentrated, which is beneficial to the miniaturization design of the power conversion device 1. Optionally, the first filter capacitor C1 can also be located between the opposite-named terminals of the first inductor winding L11 and the third inductor winding L13. The positions of the first filter capacitor C1 in the power conversion device 1 are diverse, thus making the structure of the power conversion device 1 diverse and highly flexible.

[0070] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 further includes a second filter capacitor C2 and a third filter capacitor C3. The second filter capacitor C2 is located between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13, and the third filter capacitor C3 is located between the second output terminal out of the power conversion device 1 and the grounding line PE. Optionally, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the first input terminal in1 of the power conversion device 1 and the grounding line PE; a filter capacitor located between the first output terminal out1 of the power conversion device 1 and the grounding line PE; a filter capacitor located between the opposite-named terminal of the first inductor winding L11 and the grounding line PE; a filter capacitor located between the opposite-named terminal of the second inductor winding L12 and the grounding line PE; and a filter capacitor located between the opposite-named terminal of the third inductor winding L13 and the grounding line PE.

[0071] After the power conversion device 1 starts working, the energy from the AC grid is input into the power conversion device 1 through the first input terminal in1 and the second input terminal in2. It flows through the first inductor winding L11 and the second inductor winding L12, and then flows into the AC / AC circuit 11 through the first input terminal in11 and the common terminal in / out. The energy is then rectified by the first phase bridge arm 111 and the second phase bridge arm 112 in the AC / AC circuit 11. Clearly, the first inductor winding L11 and the second inductor winding L12 can filter the AC power input from the AC grid, thereby reducing electromagnetic interference from the AC power input and interference from the AC / AC circuit 11 to the AC grid. Furthermore, the energy stored in the first bus capacitor Cbus1 after rectification by the first phase bridge arm 111 and the second phase bridge arm 112 is inverted by the second phase bridge arm 112 and the third phase bridge arm 113, and output from the first output terminal out11 and the common terminal in / out of the AC / AC circuit 11. It then flows through the third inductor winding L13 and the second inductor winding L12, and finally into the AC load through the first output terminal out1 and the second output terminal out2 of the power conversion device 1. Clearly, the second inductor winding L12 and the third inductor winding L13 can filter the AC power output from the AC / AC circuit 11, obtaining AC power that meets the normal operating noise requirements of the AC load. Therefore, it can be concluded that the first filter inductor L1 can perform the functions of the input filter inductor Lin and the output filter inductor Lou in a single-phase input, single-phase output AC / AC power supply in the prior art.

[0072] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current value of the branch containing the second inductor winding L12 (i.e., the circuit between node J1 and the midpoint a2 of the second phase bridge arm 112) is I1-I2. Similarly, based on the circuit structure and current flow direction of the single-phase input and single-phase output AC / AC power supply in the prior art, the current value of the branch containing the inductor winding Lin2 (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) in the prior art is I1. Obviously, the current flowing through the branch where the second inductor winding L12 is located in the power conversion device 1 provided in this application is significantly lower than the current flowing through the branch where the inductor winding Lin2 is located in the prior art. Therefore, the second inductor winding L12 in the power conversion device 1 can use thinner copper wire or cable, and the connecting line between node J1 and the midpoint a2 of the second phase bridge arm 112 can be made of thinner cable, thereby greatly reducing the circuit cost of the power conversion device 1.

[0073] In this embodiment, the first filter inductor L1 not only performs the functions of the input filter inductor Lin and the output filter inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art, but also, compared to the input filter inductor Lin and the output filter inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art, the first filter inductor L1 reduces one inductor winding and one inductor core, thereby reducing the size of the power conversion device 1 and lowering its circuit cost. Furthermore, since the second inductor winding L12 is a shared inductor winding for both input and output inductor filtering, and the current flowing through the shared inductor winding is significantly lower than the current flowing through the corresponding inductor winding Lin2 in the prior art, the circuit cost of the second inductor winding L12 and its corresponding connecting wires can be effectively reduced, thereby further reducing the circuit cost of the power conversion device 1. Furthermore, since the second inductor winding L2 is a common inductor winding, the second input terminal in2 of the power conversion device 1 is connected to the second output terminal out2. This allows the third filter capacitor C3 to be equivalent to the filter capacitors Cin3 and Cout3 of a single-phase input, single-phase output AC / AC power supply in the prior art. As a result, the power conversion device 1 can reduce the number of filter capacitors by one compared to a single-phase input, single-phase output AC / AC power supply in the prior art, thereby further reducing the circuit cost of the power conversion device 1.

[0074] See Figure 3c , Figure 3c This is another structural schematic diagram of the power conversion device provided in this application. For example... Figure 3c As shown, with Figure 3b Compared to the power conversion device 1 shown, Figure 3c The AC / AC circuit 11 shown is Figure 3b The AC / AC circuit 11 shown is different. Specifically, the AC / AC circuit 11 includes a first phase bridge arm 111, a second phase bridge arm 112, a first bus capacitor Cbus1, a second bus capacitor Cbus2, a first inductor Lin1, a second inductor Lout1, a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4. The types of switches in the AC / AC circuit 11 can be diodes, MOSFETs, IGBTs, or GaN transistors, etc., and this application does not limit this. For example, the following description uses a diode as the switch in the first phase bridge arm 111 and IGBTs as the other switches in the AC / AC circuit 11 besides the switch in the first phase bridge arm 111. The first phase bridge arm 111 and the second phase bridge arm 112 are connected in parallel. Specifically, the first diode D1 and the second diode D2 are connected in series to form the first phase bridge arm 111, and the fifth switch Q5 and the sixth switch Q6 are connected in series to form the second phase bridge arm 112. The cathode of the first diode D1 is connected to the collector of the fifth switch Q5, and the anode of the first diode D1 is connected to the cathode of the second diode D2. The emitter of the fifth switch Q5 is connected to the collector of the sixth switch Q6, and the emitter of the sixth switch Q6 is connected to the anode of the second diode D2. The first bus capacitor Cbus1 and the second bus capacitor Cbus2 are connected in series and then in parallel across the two ends of the first phase bridge arm 111, i.e., the cathode of the first diode D1 and the anode of the second diode D2. The series connection of the first bus capacitor Cbus1 and the second bus capacitor Cbus2 is connected to the common terminal in / out of the AC / AC circuit 11. The first switch Q1 and the second switch Q2 are connected in reverse series between the common terminal in / out of the AC / AC circuit 11 and the midpoint a1 of the first phase bridge arm 111. Specifically, the collector of the first switch Q1 is connected to the midpoint a1 of the first phase bridge arm 111, the emitter of the first switch Q1 is connected to the emitter of the second switch Q2, and the collector of the second switch Q2 is connected to the common terminal in / out of the AC / AC circuit 11. The third switch Q3 and the fourth switch Q4 are connected in reverse series between the common terminal in / out of the AC / AC circuit 11 and the midpoint a2 of the second phase bridge arm 112. Specifically, the collector of the third switch Q3 is connected to the common terminal in / out of the AC / AC circuit 11, the emitter of the third switch Q3 is connected to the emitter of the fourth switch Q4, and the collector of the fourth switch Q4 is connected to the midpoint a2 of the second phase bridge arm 112. The midpoint a1 of the first phase bridge arm 111 is connected to the first input terminal in11 of the AC / AC circuit 11 through the first inductor Lin1, and the midpoint a2 of the second phase bridge arm 112 is connected to the first output terminal out11 of the AC / AC circuit 11 through the second inductor Lout1.

[0075] Here, for the other circuit components in the power conversion device 1 besides the AC / AC circuit 11 and their connection relationships, as well as the energy flow direction of the power conversion device 1, please refer to [link to relevant documentation]. Figure 3b The description of the corresponding part in the power conversion device 1 shown is not repeated here. Assuming the input current and output current of the power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in the power conversion device 1, the current value of the branch containing the second inductor winding L12 (i.e., the circuit between node J1 and node J2) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing single-phase input, single-phase output AC / AC power supply, the current value of the branch containing the inductor winding Lin2 corresponding to the second inductor winding L12 (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current flowing through the branch where the second inductor winding L12 is located in the power conversion device 1 provided in this application is significantly lower than the current flowing through the branch where the inductor winding Lin2 is located in the prior art. Therefore, the second inductor winding L12 in the power conversion device 1 can use a thinner copper wire or cable than the inductor winding Lin2, and the connecting wire between node J1 and node J2 can be a thinner cable than the connecting wire of the branch where the inductor winding Lin2 is located, thereby greatly reducing the circuit cost of the power conversion device 1.

[0076] In this embodiment, the first filter inductor L1 not only performs the functions of the input filter inductor Lin and the output filter inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art, but also, compared to the input filter inductor Lin and the output filter inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art, the first filter inductor L1 reduces one inductor winding and one inductor core, thereby reducing the size of the power conversion device 1 and lowering its circuit cost. Furthermore, since the second inductor winding L12 is a shared inductor winding for both input and output inductor filtering, and the current flowing through the shared inductor winding is significantly lower than the current flowing through the corresponding inductor winding Lin2 in the prior art, the circuit cost of the second inductor winding L12 and its corresponding connecting wires can be effectively reduced, thereby further reducing the circuit cost of the power conversion device 1. Furthermore, since the second inductor winding L2 is a common inductor winding, the second input terminal in2 of the power conversion device 1 is connected to the second output terminal out2. This allows the third filter capacitor C3 to be equivalent to the filter capacitors Cin3 and Cout3 in the prior art. Therefore, compared to the single-phase input, single-phase output AC / AC power supplies in the prior art, the power conversion device 1 can reduce one filter capacitor, further reducing the circuit cost of the power conversion device 1. Finally, the AC / AC circuit 11 has diverse circuit structures, resulting in diverse structures and high flexibility for the power conversion device 1.

[0077] It should be noted that in this application, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through C. This application does not impose any restrictions on this.

[0078] See Figure 4a , Figure 4a This is another structural schematic diagram of the power conversion device provided in this application. (And...) Figure 3a Compared to the power conversion device 1 shown, Figure 4a The power conversion device 1 shown also includes a second filter inductor L2. Specifically, as... Figure 4a As shown, the second filter inductor L2 includes a fourth inductor winding L14, a fifth inductor winding L15, a sixth inductor winding L16, and a second inductor core.

[0079] In this power conversion device, the fourth inductor winding L14, the fifth inductor winding L15, and the sixth inductor winding L16 are all wound on the second inductor core. The first end (i.e., the same-name end) of the first inductor winding L11 is connected to the first input terminal in1 of the power conversion device 1 via the fourth inductor winding L14. Specifically, the same-name end of the first inductor winding L11 is connected to the opposite-name end of the fourth inductor winding L14, and the same-name end of the fourth inductor winding L4 is connected to the first input terminal in1 of the power conversion device 1. The first end of the second inductor winding L12 is connected to the second input terminal in2 and the second output terminal out2 of the power conversion device 1 via the fifth inductor winding L15. The first end of the third inductor winding L13 is connected to the first output terminal out1 of the power conversion device via the sixth inductor winding L16. In this application, the first end of each inductor winding can be a same-name end, and correspondingly, the second ends of all inductor windings are opposite-name ends. For details regarding the specific connections between the inductor windings of the first filter inductor L1 and the AC / AC circuit 11, as well as the circuit elements included in the AC / AC circuit 11 and their specific connections, please refer to [link to relevant documentation]. Figure 3b and Figure 3c The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0080] Optionally, the first filter capacitor C1 can also be located between the opposite-named terminals of the first inductor winding L11 and the third inductor winding L13. It is understood that when the capacitance value of the first filter capacitor C1 is equal to the sum of the capacitance values ​​of the input filter capacitor Cin2 and the output filter capacitor Cout2 in the prior art, the first filter capacitor can replace the input filter capacitor Cin2 and the output filter capacitor Cout2 in the prior art, making the filter capacitors in the power conversion device 1 more concentrated, which is beneficial to the miniaturization design of the power conversion device 1. Optionally, the first filter capacitor C1 can also be located between the same-named terminals of the first inductor winding L11 and the third inductor winding L13. It is understood that the various positions of the first filter capacitor C1 in the power conversion device 1 result in diverse structures and high flexibility for the power conversion device 1.

[0081] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13; a filter capacitor located between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13; a filter capacitor located between the first input terminal in1 of the power conversion device 1 and the ground wire PE; a filter capacitor located between the first output terminal out1 of the power conversion device 1 and the ground wire PE; and a filter capacitor located between the second input terminal in2 of the power conversion device 1 and the ground wire PE. The filter capacitor between the grounding wire PE, the filter capacitor between the opposite terminal of the first inductor winding L11 and the grounding wire PE, the filter capacitor between the opposite terminal of the second inductor winding L12 and the grounding wire PE, the filter capacitor between the opposite terminal of the third inductor winding L13 and the grounding wire PE, the filter capacitor between the same terminal of the first inductor winding L11 and the grounding wire PE, the filter capacitor between the same terminal of the second inductor winding L12 and the grounding wire PE, and the filter capacitor between the same terminal of the third inductor winding L13 and the grounding wire PE.

[0082] based on Figure 4a As can be seen from the circuit structure of the power conversion device 1 shown, Figure 4aThe power conversion device 1 shown is suitable for single-phase input and single-phase output applications, where both the input and output terminals are two-stage inductor filters. After the power conversion device 1 operates, energy from the AC grid enters the device from its first input terminal in1 and second input terminal in2, flows through the fourth inductor winding L14, the first inductor winding L11, the fifth inductor winding L15, and the second inductor winding L12, and then flows into the AC / AC circuit 11 from its first input terminal in11 and the common terminal in / out. Clearly, the first inductor winding L11, the second inductor winding L12, the fourth inductor winding L14, and the fifth inductor winding L15 can filter the AC power input from the AC grid, thereby better reducing electromagnetic interference and suppressing switching ripple on the input side of the AC / AC circuit 11, preventing switching noise from interfering with grid-side equipment. Furthermore, the energy converted by the AC / AC circuit 11 flows out from the first output terminal out11 and the common terminal in / out of the AC / AC circuit 11, and flows into the AC load after passing through the third inductor winding L13, the sixth inductor winding L16, the second inductor winding L12, and the fifth inductor winding L15. Clearly, the second inductor winding L12, the third inductor winding L13, the fifth inductor winding L15, and the sixth inductor winding L16 can filter the AC output of the AC / AC circuit, obtaining AC power that meets the normal operating noise requirements of the AC load and has lower noise. Therefore, the first filter inductor L1 and the second filter inductor L2 can achieve the function of two-stage inductor filtering at the input end (i.e., two input filter inductors) and two-stage inductor filtering at the output end (i.e., two output filter inductors) of a single-phase input, single-phase output AC / AC power supply in the prior art. For example, a single-phase input, single-phase output AC / AC power supply with two-stage inductor filtering at both the input and output ends is... Figure 1 An input filter inductor is added between the input terminal of the AC / AC power supply and the input filter inductor, and... Figure 1 The AC / AC power supply shown is an AC / AC power supply with an added output filter inductor between the output terminal and the output filter inductor.

[0083] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current value of the branch containing the fifth inductor winding L15 and the second inductor winding L12 (i.e., the circuit between node J1 and the common terminal in / out of AC / AC circuit 11) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing AC / AC power supply with two-stage inductor filtering at both the input and output ends, and a single-phase input and single-phase output, it can be known that the current value of the branch corresponding to the two inductor windings L15 and L12 (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current values ​​of the branches containing the second inductor winding L12 and the fifth inductor winding L15 in the power conversion device 1 provided in this application are significantly lower than the current values ​​of the corresponding branches containing the two inductor windings in the prior art. Therefore, the second inductor winding L12 and the fifth inductor winding L15 in the power conversion device 1 can both use thinner copper wires or cables, and the connection lines between node J1 and the common terminals in / out of the AC / AC circuit can both use thinner cables, thereby significantly reducing the circuit cost of the power conversion device 1.

[0084] In this embodiment, the first filter inductor L1 and the second filter inductor L2 not only achieve the functions of the two-stage filter inductors at the input and output ends of a single-phase input, single-phase output AC / AC power supply in the prior art, but also, compared to the two-stage filter inductors at the input and output ends of a single-phase input, single-phase output AC / AC power supply in the prior art, the first filter inductor L1 and the second filter inductor L2 reduce two inductor windings and two inductor cores, thereby reducing the size of the power conversion device 1 and lowering its circuit cost. Furthermore, since the second inductor winding L12 and the fifth inductor winding L15 are both shared inductor windings for input and output inductor filtering, and the current flowing through the shared inductor winding is significantly lower than the current flowing through the corresponding two inductor windings in the prior art, the circuit cost of the second inductor winding L12 and the fifth inductor winding L15 and their corresponding connecting lines can be effectively reduced, thereby further reducing the circuit cost of the power conversion device 1.

[0085] See Figure 4b , Figure 4b This is another structural schematic diagram of the power conversion device provided in this application. For example... Figure 4b As shown, with Figure 4a Compared to the power conversion device 1 shown, Figure 4b The second filter inductor L2 shown is Figure 4aThe second filter inductor L2 shown is different. Specifically, the second filter inductor L2 includes a fourth inductor winding L14, a fifth inductor winding L15, a sixth inductor winding L16, a seventh inductor winding L17, and a second inductor core. The fourth inductor winding L14, the fifth inductor winding L15, the sixth inductor winding L16, and the seventh inductor winding L17 are all wound on the second inductor core. The first end of the first inductor winding L11 is connected to the first input terminal in1 of the power conversion device 1 through the fourth inductor winding L14. The first end of the second inductor winding L12 is connected to the second input terminal in2 of the power conversion device 1 through the fifth inductor winding L15, and the first end of the second inductor winding L12 is connected to the second output terminal out2 of the power conversion device 1 through the sixth inductor winding L16. The first end of the third inductor winding L13 is connected to the first output terminal out1 of the power conversion device 1 through the seventh inductor winding L17. In this application, the first end of the inductor winding can be a terminal with the same name, and the corresponding second end of the inductor winding is a terminal with a different name.

[0086] here, Figure 4b For the circuit components and their connections in the power conversion device 1 shown, excluding the second filter inductor L2, please refer to [link to relevant documentation]. Figure 4a The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0087] Optionally, the power conversion device 1 also includes a first filter capacitor C1. For example, the first filter capacitor C1 is located between the second input terminal in2 and the second output terminal out2 of the power conversion device 1. It is understood that when the capacitance value of the first filter capacitor C1 is equal to the sum of the capacitance values ​​of the input filter capacitor Cin3 and the output filter capacitor Cout3 in the prior art, the first filter capacitor C1 can replace the input filter capacitor Cin3 and the output filter capacitor Cout3 in the prior art, making the filter capacitors in the power conversion device 1 more concentrated, which is beneficial for the miniaturization design of the power conversion device 1. Optionally, the first filter capacitor C1 can also be located between the first input terminal in1 and the first output terminal out1 of the power conversion device 1, or between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13, or between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13. It is understood that the diverse locations of the first filter capacitor C1 in the power conversion device 1 result in diverse structures and high flexibility for the power conversion device 1.

[0088] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13; a filter capacitor located between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13; a filter capacitor located between the first input terminal in1 of the power conversion device 1 and the grounding wire PE; a filter capacitor located between the first output terminal out1 of the power conversion device 1 and the grounding wire PE; a filter capacitor located between the second input terminal in2 of the power conversion device 1 and the grounding wire PE; and a filter capacitor located between the first input terminal in1 and the grounding wire PE. The filter capacitor between the second output terminal out2 of the power conversion device 1 and the grounding line PE, the filter capacitor between the opposite terminal of the first inductor winding L11 and the grounding line PE, the filter capacitor between the opposite terminal of the second inductor winding L12 and the grounding line PE, the filter capacitor between the opposite terminal of the third inductor winding L13 and the grounding line PE, the filter capacitor between the same terminal of the first inductor winding L11 and the grounding line PE, the filter capacitor between the same terminal of the second inductor winding L12 and the grounding line PE, and the filter capacitor between the same terminal of the third inductor winding L13 and the grounding line PE.

[0089] based on Figure 4b As can be seen from the circuit structure of the power conversion device 1 shown, Figure 4bThe power conversion device 1 shown is also suitable for single-phase input and single-phase output applications, where both the input and output terminals use two-stage inductor filtering. After the power conversion device 1 operates, energy from the AC grid enters the device from its first input terminal in1 and second input terminal in2, flows through the fourth inductor winding L14, the first inductor winding L11, the fifth inductor winding L15, and the second inductor winding L12, and then flows into the AC / AC circuit 11 from its first input terminal in11 and the common terminal in / out. Clearly, the first inductor winding L11, the second inductor winding L12, the fourth inductor winding L14, and the fifth inductor winding L15 can filter the AC power input from the AC grid, thereby better reducing electromagnetic interference and suppressing switching ripple on the input side of the AC / AC circuit 11, preventing switching noise from interfering with the grid-side equipment. Furthermore, the energy converted by the AC / AC circuit 11 flows out from the first output terminal out11 and the common terminal in / out of the AC / AC circuit 11, and flows into the AC load after passing through the third inductor winding L13, the seventh inductor winding L17, the second inductor winding L12, and the sixth inductor winding L16. Clearly, the second inductor winding L12, the third inductor winding L13, the sixth inductor winding L16, and the seventh inductor winding L17 can filter the AC power output from the AC / AC circuit 11, obtaining AC power that meets the normal operating noise requirements of the AC load and has lower noise. Therefore, the first filter inductor L1 and the second filter inductor L2 can achieve the function of two-stage inductor filtering at the input and two-stage inductor filtering at the output of a single-phase input, single-phase output AC / AC power supply in the prior art.

[0090] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current value of the branch where the second inductor winding L12 is located (i.e., the circuit between node J3 and the common terminal in / out of AC / AC circuit 11) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing AC / AC power supply with two-stage inductor filtering at both the input and output ends, and a single-phase input and single-phase output, it can be known that the current value of the branch where the inductor winding Lin2 corresponding to the second inductor winding L12 is located (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current value of the branch where the second inductor winding L12 is located in the power conversion device 1 provided in this application is significantly lower than the current value of the branch where the corresponding inductor winding Lin2 is located in the prior art. Therefore, the second inductor winding L12 in the power conversion device 1 can use thinner copper wire or cable, and the connection line between node J3 and the common terminal in / out of AC / AC circuit 11 can use thinner cable, thereby greatly reducing the circuit cost of the power conversion device 1.

[0091] In this embodiment, the first filter inductor L1 and the second filter inductor L2 not only achieve the functions of the two-stage filter inductors at the input and output ends of a single-phase input, single-phase output AC / AC power supply in the prior art, but also, compared to the two-stage filter inductors at the input and output ends of a single-phase input, single-phase output AC / AC power supply in the prior art, the first filter inductor L1 and the second filter inductor L2 reduce one inductor winding and two inductor cores, thereby reducing the size of the power conversion device 1 and lowering its circuit cost. Furthermore, since the second inductor winding L12 is a shared inductor winding for both input and output inductor filtering, and the current flowing through the shared inductor winding is significantly lower than the current flowing through the corresponding inductor winding Lin2 in the prior art, the circuit cost of the second inductor winding L12 and its corresponding connecting wires can be effectively reduced, thereby further reducing the circuit cost of the power conversion device 1. Furthermore, in addition to the structure of three inductor windings and one inductor core, the second filter inductor L2 can also be structured with four inductor windings and one inductor core, thus making the circuit structure of the power conversion device 1 diverse and highly flexible.

[0092] See Figure 4c , Figure 4c This is another structural schematic diagram of the power conversion device provided in this application. For example... Figure 4c As shown, with Figure 4a Compared to the power conversion device 1 shown, Figure 4c The second filter inductor L2 shown is Figure 4a The second filter inductor L2 shown is different. Specifically, the second filter inductor L2 includes a fourth inductor winding L14, a fifth inductor winding L15, and a second inductor core. Both the fourth inductor winding L14 and the fifth inductor winding L15 are wound on the second inductor core. The first end of the first inductor winding L11 is connected to the first input terminal in1 of the power conversion device 1 through the fourth inductor winding L14. The first end of the second inductor winding L12 is connected to the second input terminal in2 of the power conversion device 1 through the fifth inductor winding L15. In this application, the first ends of the inductor windings can be terminals with the same name, and correspondingly, the second ends of the inductor windings are all terminals with different names.

[0093] here, Figure 4c For the circuit components and their connections in the power conversion device 1 shown, excluding the second filter inductor L2, please refer to [link to relevant documentation]. Figure 4a The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0094] Optionally, the power conversion device 1 further includes a first filter capacitor C1. For example, the first filter capacitor C1 is connected between the same-name terminal of the first inductor winding L11 and the same-name terminal of the third inductor winding L13. Optionally, the first filter capacitor C1 may also be located between the first input terminal in1 and the first output terminal out1 of the power conversion device 1, or between the second input terminal in2 and the second output terminal out2 of the power conversion device 1, or between the opposite-name terminal of the first inductor winding L11 and the opposite-name terminal of the third inductor winding L13. It is understood that the location of the first filter capacitor C1 in the power conversion device 1 is diverse, thus making the structure of the power conversion device 1 diverse and highly flexible.

[0095] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the first input terminal in1 and the first output terminal out1 of the power conversion device 1; a filter capacitor located between the second input terminal in2 and the second output terminal out2 of the power conversion device 1; a filter capacitor located between the opposite-named terminals of the first inductor winding L11 and the third inductor winding L13; a filter capacitor located between the first input terminal in1 of the power conversion device 1 and the ground wire PE; and a filter capacitor located between the first output terminal out1 of the power conversion device 1 and the ground wire PE. The filter capacitors are located between the second input terminal in2 of the power conversion device 1 and the grounding line PE, the filter capacitors are located between the second output terminal out2 of the power conversion device 1 and the grounding line PE, the filter capacitors are located between the opposite terminal of the first inductor winding L11 and the grounding line PE, the filter capacitors are located between the opposite terminal of the second inductor winding L12 and the grounding line PE, the filter capacitors are located between the opposite terminal of the third inductor winding L13 and the grounding line PE, the filter capacitors are located between the same terminal of the second inductor winding L12 and the grounding line PE, and the filter capacitors are located between the same terminal of the third inductor winding L13 and the grounding line PE.

[0096] based on Figure 4c As can be seen from the circuit structure of the power conversion device 1 shown, Figure 4cThe power conversion device 1 shown is suitable for applications with single-phase input and single-phase output, a two-stage inductor filter at the input, and a single-stage inductor filter at the output. Furthermore, assuming the input and output currents of the power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in the power conversion device 1, the current flowing through the branch containing the second inductor winding L12 (i.e., the circuit between node J4 and the common terminal in / out of the AC / AC circuit 11) is I1-I2. Similarly, based on the circuit structure and current flow direction of the existing AC / AC power supply with a two-stage inductor filter at the input and a single-stage inductor filter at the output, and a single-phase input and single-phase output, the current flowing through the branch corresponding to the second inductor winding L12 Lin2 (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current value of the branch where the second inductor winding L12 is located in the power conversion device 1 provided in this application is significantly lower than the current value of the branch where the corresponding inductor winding Lin2 is located in the prior art. Therefore, the second inductor winding L12 in the power conversion device 1 can use thinner copper wire or cable, and the connection line between node J4 and the common terminal in / out of AC / AC circuit 11 can also use thinner cable, thereby greatly reducing the circuit cost of the power conversion device 1.

[0097] In this embodiment, the first filter inductor L1 can perform the functions of the input filter inductor Lin and the output filter inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art. Moreover, compared with the input filter inductor Lin and the output filter inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art, the first filter inductor L1 reduces one inductor winding and one inductor core, thereby reducing the size of the power conversion device 1 and the circuit cost of the power conversion device 1. In addition, since the second inductor winding L12 is a common inductor winding for both input and output inductor filtering, and the current flowing through the common inductor winding is significantly lower than the current flowing through the corresponding inductor winding Lin2 in the prior art, the circuit cost of the second inductor winding L12 and its corresponding connecting wires can be effectively reduced, thereby further reducing the circuit cost of the power conversion device 1.

[0098] It should be noted that, Figure 4c The second filter inductor L2 can be located outside the AC input terminal of the power conversion device 1, or it can be located at the AC output terminal of the power conversion device 1. Please refer to [link to relevant documentation] for details. Figure 4d The power conversion device 1 shown is based on... Figure 4d As can be seen from the circuit structure of the power conversion device 1 shown, Figure 4dThe power conversion device 1 shown is suitable for applications with single-phase input and single-phase output, where the input terminal has a single-stage inductor filter and the output terminal has a two-stage inductor filter. Here, Figure 4d Please refer to the circuit structure and energy flow direction of the power conversion device 1 shown. Figure 4c The description of the corresponding part in the power conversion device 1 shown is not repeated here. Furthermore, Figure 4c The power conversion device 1 shown may further include a third filter inductor located at the AC output terminal of the power conversion device 1. This makes the power conversion device 1 suitable for single-phase input and single-phase output applications where both the input and output terminals use two-stage inductor filtering. The specific location of the third filter inductor can be found in [reference needed]. Figure 4d The location of the second filter inductor L2 shown, the circuit structure of the power conversion device 1 including the third filter inductor, and the energy flow direction can all be found in [reference needed]. Figure 4d The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0099] See Figure 5a , Figure 5a This is another structural schematic diagram of the power conversion device provided in this application. For example... Figure 5a As shown, with Figure 3a Compared to the power conversion device 1 shown, the AC output terminals of the power conversion device 1 further include a third output terminal out3 and a fourth output terminal out4, the first filter inductor L1 further includes a fourth inductor winding L14 and a fifth inductor winding L15, and the output terminals of the AC / AC circuit 11 further include a second output terminal out12 and a third output terminal out13. Specifically, the first end of the fourth inductor winding L14 is connected to the third output terminal out3 of the power conversion device 1, and the second end of the fourth inductor winding L14 is connected to the second output terminal out12 of the AC / AC circuit 11. The first end of the fifth inductor winding L15 is connected to the fourth output terminal out4 of the power conversion device 1, and the second end of the fifth inductor winding L15 is connected to the third output terminal out13 of the AC / AC circuit 11. In this application, the first ends of the inductor windings can be terminals with the same name, and correspondingly, the second ends of the inductor windings are all terminals with different names.

[0100] The power conversion device 1 also includes a first filter capacitor C1, a second filter capacitor C2, and a third filter capacitor C3. For a description of the first filter capacitor C1, the second filter capacitor C2, and the third filter capacitor C3, please refer to [link to relevant documentation]. Figure 3b The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0101] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the first input terminal in1 and the grounding line PE of the power conversion device 1; a filter capacitor located between the first output terminal out1 and the grounding line PE of the power conversion device 1; a filter capacitor located between the third output terminal out3 and the grounding line PE of the power conversion device 1; a filter capacitor located between the fourth output terminal out4 and the grounding line PE of the power conversion device 1; a filter capacitor located between the first input terminal in1 and the second input terminal in2 of the power conversion device 1; a filter capacitor located between the first output terminal out1 and the second output terminal out2 of the power conversion device 1; a filter capacitor located between the second output terminal out2 and the third output terminal out3 of the power conversion device 1; a filter capacitor located between the second output terminal out2 and the fourth output terminal out4 of the power conversion device 1; and a filter capacitor located between the opposite terminal of the first inductor winding L11 and the grounding line PE. The filter capacitors located between the opposite terminals of the second inductor winding L12 and the grounding line PE, the filter capacitors located between the opposite terminals of the third inductor winding L13 and the grounding line PE, the filter capacitors located between the opposite terminals of the fourth inductor winding L14 and the grounding line PE, the filter capacitors located between the opposite terminals of the fifth inductor winding L15 and the grounding line PE, the filter capacitors located between the opposite terminals of the first inductor winding L11 and the second inductor winding L12, and the filter capacitors located between the opposite terminals of the third inductor winding L13 and the second inductor winding L12. The filter capacitors are located between the opposite-named terminals of the fourth inductor winding L14 and the second inductor winding L12, the filter capacitors between the opposite-named terminals of the fifth inductor winding L15 and the second inductor winding L12, the filter capacitors between the opposite-named terminals of the third inductor winding L13 and the fourth inductor winding L14, the filter capacitors between the opposite-named terminals of the third inductor winding L13 and the fifth inductor winding L15, and the filter capacitors between the opposite-named terminals of the fourth inductor winding L14 and the fifth inductor winding L15.

[0102] It should be noted that when the capacitance value of the first filter capacitor C1 is the sum of the capacitance values ​​of the filter capacitor located between the first input terminal in1 and the second input terminal in2 of the power conversion device 1, and the filter capacitor located between the first output terminal out1 and the second output terminal out2 of the power conversion device 1, the first filter capacitor C1 can replace the filter capacitor located between the first input terminal in1 and the second input terminal in2 of the power conversion device 1, and the filter capacitor located between the first output terminal out1 and the second output terminal out2 of the power conversion device 1. This reduces the number of filter capacitors in the power conversion device 1, and makes the positions of the filter capacitors in the power conversion device 1 more concentrated, which is beneficial to the miniaturization design of the power conversion device 1.

[0103] Here, AC / AC circuit 11 can be adopted. Figure 5b The AC / AC circuit 11 shown is as follows: Figure 5b As shown, the AC / AC circuit 11 includes a first phase bridge arm 111, a second phase bridge arm 112, a third phase bridge arm 113, a fourth phase bridge arm 114, a first bus capacitor Cbus1, a second bus capacitor Cbus2, a first inductor Lin1, a second inductor Lout1, a third inductor Lout2, and a fourth inductor Lout3. The first phase bridge arm 111, the second phase bridge arm 112, the third phase bridge arm 113, and the fourth phase bridge arm 114 are connected in parallel. Specifically, switching transistors Q11 and Q12 are connected in series to form the first phase bridge arm 111, switching transistors Q21 and Q22 are connected in series to form the second phase bridge arm 112, switching transistors Q31 and Q32 are connected in series to form the third phase bridge arm 113, and switching transistors Q41 and Q42 are connected in series to form the fourth phase bridge arm 114. The first bus capacitor Cbus1 and the second bus capacitor Cbus2 are connected in series and then in parallel across the two ends of the first phase bridge arm 111. The connection point J5 between the first bus capacitor Cbus1 and the second bus capacitor Cbus2 is connected to the common terminal in / out of the AC / AC circuit 11. The midpoint a1 of the first phase bridge arm 111, i.e., the series connection of switching transistors Q11 and Q12, is connected to the first input terminal in11 of the AC / AC circuit 11 through the first inductor Lin1. The midpoint a2 of the second phase bridge arm 112, i.e., the series connection of switching transistors Q21 and Q22, is connected to the first output terminal out11 of the AC / AC circuit 11 through the second inductor Lout1. The midpoint a3 of the third phase bridge arm 113, i.e., the series connection of switching transistors Q31 and Q32, is connected to the second output terminal out12 of the AC / AC circuit 11 through the third inductor Lout2. The midpoint a4 of the fourth phase bridge arm 114, which is the series connection point of switch Q41 and switch Q42, is connected to the third output terminal out13 of AC / AC circuit 11 through the fourth inductor Lout3.

[0104] After the power conversion device 1 starts working, the energy from the AC grid is input into the power conversion device 1 from the first input terminal in1 and the second input terminal in2. It flows through the first inductor winding L11 and the second inductor winding L12, and then flows into the AC / AC circuit 11 from the first input terminal in11 and the common terminal in / out. The energy is then rectified by the first phase bridge arm 111 and the second phase bridge arm 112 in the AC / AC circuit 11. Clearly, the first inductor winding L11 and the second inductor winding L12 can filter the AC power input from the AC grid and filter the grid side of the AC / AC circuit 11, thereby reducing electromagnetic interference from the AC power input from the AC grid and interference from the AC / AC circuit 11 to the power grid. Furthermore, the energy stored in the first bus capacitor Cbus1 and the second bus capacitor Cbus2 after rectification by the first phase bridge arm 111 and the second phase bridge arm 112 is inverted by the second phase bridge arm 112, the third phase bridge arm 113, and the fourth phase bridge arm 114 and output from the first output terminal out11, the second output terminal out12, the third output terminal out13, and the common terminal in / out of the AC / AC circuit 11. This energy then flows into the AC load after passing through the third inductor winding L13, the fourth inductor winding L14, the fifth inductor winding L15, and the second inductor winding L12. Clearly, the second inductor winding L12, the third inductor winding L13, the fourth inductor winding L14, and the fifth inductor winding L15 can filter the AC output from the AC / AC circuit 11, obtaining AC power that meets the normal operating noise requirements of the AC load. Therefore, it can be concluded that the first filter inductor L1 can realize the functions of an input filter inductor with 2 inductor windings and an output filter inductor with 4 inductor windings in a single-phase input and three-phase output AC / AC power supply in the prior art.

[0105] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current value of the branch containing the second inductor winding L12 (i.e., the circuit between node J1 and node J5) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing single-phase input three-phase output AC / AC power supply, the current value of the branch containing the inductor winding Lin2 (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current flowing through the branch where the second inductor winding L12 is located in the power conversion device 1 provided in this application is significantly lower than the current flowing through the branch where the inductor winding Lin2 is located in the prior art. Therefore, the second inductor winding L12 in the power conversion device 1 can use thinner copper wire or cable, and the connecting line between node J1 and node J5 can be made of thinner cable, thereby greatly reducing the circuit cost of the power conversion device 1.

[0106] In this embodiment, the first filter inductor L1 not only performs the functions of the input filter inductor and output filter inductor in a single-phase input, three-phase output AC / AC power supply in the prior art, but also reduces the size of the power conversion device 1 and its circuit cost compared to the input and output filter inductors in a single-phase input, three-phase output AC / AC power supply in the prior art. Furthermore, since the second inductor winding L12 is a shared inductor winding for both input and output inductor filtering, and the current flowing through this shared inductor winding is significantly lower than the current flowing through the corresponding inductor winding Lin2 in the prior art, the circuit cost of the second inductor winding L12 and its corresponding connecting wires can be effectively reduced, thereby further reducing the circuit cost of the power conversion device 1. Furthermore, since the second inductor winding L2 is a common inductor winding, the second input terminal in2 of the power conversion device 1 is connected to the second output terminal out2. As a result, the third filter capacitor C3 can be equivalent to the filter capacitors Cin3 and Cout3 in the prior art. Therefore, compared with the AC / AC power supply in the prior art, the power conversion device 1 can reduce one filter capacitor, thereby further reducing the circuit cost of the power conversion device 1.

[0107] See Figure 5c , Figure 5c This is another structural schematic diagram of the power conversion device provided in this application. (And...) Figure 5a Compared to the power conversion device 1 shown, Figure 5c The power conversion device 1 shown also includes a second filter inductor L2. Specifically, as... Figure 5c As shown, the second filter inductor L2 includes a sixth inductor winding L16, a seventh inductor winding L17, an eighth inductor winding L18, a ninth inductor winding L19, a tenth inductor winding L110, and a second inductor core.

[0108] The sixth inductor winding L16, the seventh inductor winding L17, the eighth inductor winding L18, the ninth inductor winding L19, and the tenth inductor winding L110 are all wound on the second inductor core. The first end of the first inductor winding L11 is connected to the first input terminal in1 of the power conversion device 1 via the sixth inductor winding L16. The first end of the second inductor winding L12 is connected to the second input terminal in2 and the second output terminal out2 of the power conversion device 1 via the seventh inductor winding L17. The first end of the third inductor winding L13 is connected to the first output terminal out1 of the power conversion device via the eighth inductor winding L18. The first end of the fourth inductor winding L14 is connected to the third output terminal out3 of the power conversion device 1 via the ninth inductor winding L19. The first end of the fifth inductor winding L15 is connected to the fourth output terminal out4 of the power conversion device 1 via the tenth inductor winding L110.

[0109] In this application, the first end of the inductor winding can be a same-named end, and correspondingly, the second end of the inductor winding is a different-named end. For the specific connection relationship between each inductor winding in the first filter inductor L1 and the AC / AC circuit 11, as well as the circuit elements included in the AC / AC circuit 11 and their specific connection relationships, please refer to [link to relevant documentation]. Figure 5a and Figure 5b The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0110] Optionally, the first filter capacitor C1 can also be located between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13, or between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13. Understandably, the position of the first filter capacitor C1 in the power conversion device 1 is diverse, thus making the structure of the power conversion device 1 diverse and highly flexible.

[0111] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13; a filter capacitor located between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13; a filter capacitor located between the first input terminal in1 of the power conversion device 1 and the grounding wire PE; a filter capacitor located between the second input terminal in2 of the power conversion device 1 and the grounding wire PE; a filter capacitor located between the first output terminal out1 of the power conversion device 1 and the grounding wire PE; and a filter capacitor located between the second output terminal out2 of the power conversion device 1 and the grounding wire PE. The filter capacitors located between the third output terminal out3 of power conversion device 1 and the grounding wire PE, the filter capacitors located between the fourth output terminal out4 of power conversion device 1 and the grounding wire PE, the filter capacitors located between the first input terminal in1 and the second input terminal in2 of power conversion device 1, the filter capacitors located between the first output terminal out1 and the second output terminal out2 of power conversion device 1, the filter capacitors located between the third output terminal out3 and the second output terminal out2 of power conversion device 1, the filter capacitors located between the fourth output terminal out4 and the second output terminal out2 of power conversion device 1, and the filter capacitors located between the first input terminal in1 and the second input terminal in2 of power conversion device 1. The filter capacitors located between the output terminals out1 and out3, the first output terminal out1 and the fourth output terminal out4 of the power conversion device 1, the third output terminal out3 and the fourth output terminal out4 of the power conversion device 1, the filter capacitors located between the opposite-named terminal of the first inductor winding L11 and the grounding wire PE, the filter capacitors located between the opposite-named terminal of the second inductor winding L12 and the grounding wire PE, the filter capacitors located between the opposite-named terminal of the third inductor winding L13 and the grounding wire PE, the filter capacitors located between the opposite-named terminal of the fourth inductor winding L14 and the grounding wire PE, and the filter capacitors located between the opposite-named terminal of the fifth inductor winding L15 and the grounding wire PE. The filter capacitors are located between the line and the protective earth (PE) terminals; between the opposite terminals of the first inductor winding L11 and the second inductor winding L12; between the opposite terminals of the third inductor winding L13 and the second inductor winding L12; between the opposite terminals of the fourth inductor winding L14 and the second inductor winding L12; between the opposite terminals of the fifth inductor winding L15 and the second inductor winding L12; and between the opposite terminals of the third inductor winding L13 and the fourth inductor winding L14.The filter capacitors located between the opposite-named terminals of the fourth inductor winding L14 and the fifth inductor winding L15, the filter capacitors located between the same-named terminal of the first inductor winding L11 and the grounding line PE, the filter capacitors located between the same-named terminal of the second inductor winding L12 and the grounding line PE, the filter capacitors located between the same-named terminal of the third inductor winding L13 and the grounding line PE, the filter capacitors located between the same-named terminal of the fourth inductor winding L14 and the grounding line PE, the filter capacitors located between the same-named terminal of the fifth inductor winding L15 and the grounding line PE, and the filter capacitors located between the same-named terminals of the first inductor winding L11 and the second inductor winding L12, are listed below. The filter capacitors located between the corresponding terminals of the third inductor winding L13 and the second inductor winding L12, the fourth inductor winding L14 and the second inductor winding L12, the fifth inductor winding L15 and the second inductor winding L12, the third inductor winding L13 and the fourth inductor winding L14, the third inductor winding L13 and the fifth inductor winding L15, and the fourth inductor winding L14 and the fifth inductor winding L15.

[0112] based on Figure 5c As can be seen from the circuit structure of the power conversion device 1 shown, Figure 5c The power conversion device 1 shown is suitable for single-phase input and three-phase output applications, with both the input and output ends using two-stage inductor filtering. Based on the energy flow after the power conversion device 1 is operational, the first inductor winding L11, the second inductor winding L12, the sixth inductor winding L16, and the seventh inductor winding L17 can filter the AC power input from the AC grid, thereby better reducing electromagnetic interference from the AC power input and better suppressing the switching ripple on the input side of the AC / AC circuit 11, preventing switching noise from interfering with grid-side equipment. The second inductor winding L12, the third inductor winding L13, the fourth inductor winding L15, the fifth inductor winding L15, the seventh inductor winding L17, the eighth inductor winding L18, the ninth inductor winding L19, and the tenth inductor winding L110 can filter the AC power output from the AC / AC circuit 11, obtaining AC power that meets the normal operating noise requirements of the AC load and has lower noise levels. Thus, the first filter inductor L1 and the second filter inductor L2 can achieve the functions of two-stage inductor filtering at the input end and two-stage inductor filtering at the output end in the existing single-phase input and three-phase output AC / AC power supply.

[0113] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current value of the branch containing the seventh inductor winding L17 and the second inductor winding L12 (i.e., the circuit between node J6 and the common terminal in / out of AC / AC circuit 11) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing AC / AC power supply with two-stage inductor filtering at both the input and output ends and single-phase input, it can be known that the current value of the branch corresponding to the seven inductor winding L17 and the second inductor winding L12 (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current values ​​of the branches containing the second inductor winding L12 and the seventh inductor winding L17 in the power conversion device 1 provided in this application are significantly lower than the current values ​​of the branches containing the corresponding two inductor windings in the prior art. Therefore, the second inductor winding L12 and the seventh inductor winding L17 in the power conversion device 1 can both use thinner copper wires or cables, and the connection lines between node J6 and the common terminals in / out of the AC / AC circuit can both use thinner cables, thereby significantly reducing the circuit cost of the power conversion device 1.

[0114] In this embodiment, compared to the two-stage input and two-stage output filter inductors of a single-phase input, three-phase output AC / AC power supply in the prior art, the first filter inductor L1 and the second filter inductor L2 reduce two inductor windings and two inductor cores, thereby reducing the size of the power conversion device 1 and lowering its circuit cost. Furthermore, since the second inductor winding L12 and the seventh inductor winding L17 are shared inductor windings for both input and output inductor filtering, and the current flowing through the shared inductor winding is significantly lower than that of the corresponding two inductor windings in the prior art, the circuit cost of the second inductor winding L12, the seventh inductor winding L17, and their corresponding connecting wires can be effectively reduced, further lowering the circuit cost of the power conversion device 1.

[0115] See Figure 5d , Figure 5d This is another structural schematic diagram of the power conversion device provided in this application. For example... Figure 5d As shown, with Figure 5c Compared to the power conversion device 1 shown, Figure 5d The second filter inductor L2 shown is Figure 5cThe second filter inductor L2 shown is different. Specifically, the second filter inductor L2 includes a sixth inductor winding L16, a seventh inductor winding L17, an eighth inductor winding L18, a ninth inductor winding L19, a tenth inductor winding L110, an eleventh inductor winding L111, and a second inductor core. The sixth inductor winding L16, the seventh inductor winding L17, the eighth inductor winding L18, the ninth inductor winding L19, the tenth inductor winding L110, and the eleventh inductor winding L111 are all wound on the second inductor core. The first end of the first inductor winding L11 is connected to the first input terminal in1 of the power conversion device 1 through the sixth inductor winding L16. The first end of the second inductor winding L12 is connected to the second input terminal in2 of the power conversion device 1 through the seventh inductor winding L17, and the first end of the second inductor winding L12 is connected to the second output terminal out2 of the power conversion device 1 through the eighth inductor winding L18. The first end of the third inductor winding L13 is connected to the first output terminal out1 of the power conversion device 1 through the ninth inductor winding L19. The first end of the fourth inductor winding L14 is connected to the third output terminal out3 of the AC conversion device 1 through the tenth inductor winding L110. The first end of the fifth inductor winding L15 is connected to the fourth output terminal out4 of the AC conversion device through the eleventh inductor winding L111.

[0116] here, Figure 5d For the circuit components and their connections in the power conversion device 1 shown, excluding the second filter inductor L2, please refer to [link to relevant documentation]. Figure 5c The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0117] The power conversion device 1 also includes a first filter capacitor C1. For example, the first filter capacitor C1 is located between the second input terminal in2 and the second output terminal out2 of the power conversion device 1. Optionally, the first filter capacitor C1 can also be located between the first input terminal in1 and the first output terminal out1 of the power conversion device 1, or between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13, or between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13. It is understood that the location of the first filter capacitor C1 in the power conversion device 1 is diverse, thus making the structure of the power conversion device 1 diverse and highly flexible.

[0118] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13; a filter capacitor located between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13; a filter capacitor located between the first input terminal in1 of the power conversion device 1 and the grounding wire PE; a filter capacitor located between the second input terminal in2 of the power conversion device 1 and the grounding wire PE; a filter capacitor located between the first output terminal out1 of the power conversion device 1 and the grounding wire PE; and a filter capacitor located between the second output terminal out2 of the power conversion device 1 and the grounding wire PE. The filter capacitors are located between the third output terminal out3 of the power conversion device 1 and the grounding line PE, the fourth output terminal out4 of the power conversion device 1 and the grounding line PE, the first input terminal in1 and the second input terminal in2 of the power conversion device 1, the first output terminal out1 and the second output terminal out2 of the power conversion device 1, the third output terminal out3 and the second output terminal out2 of the power conversion device 1, the fourth output terminal out4 and the second output terminal out2 of the power conversion device 1, and the first output terminal in1 and the second input terminal in2 of the power conversion device 1. The filter capacitor between out1 and the third output terminal out3, the filter capacitor between the first output terminal out1 and the fourth output terminal out4 of the power conversion device 1, the filter capacitor between the third output terminal out3 and the fourth output terminal out4 of the power conversion device 1, the filter capacitor between the opposite terminal of the first inductor winding L11 and the grounding wire PE, the filter capacitor between the opposite terminal of the second inductor winding L12 and the grounding wire PE, the filter capacitor between the opposite terminal of the third inductor winding L13 and the grounding wire PE, the filter capacitor between the opposite terminal of the fourth inductor winding L14 and the grounding wire PE, and the filter capacitor between the opposite terminal of the fifth inductor winding L15 and the grounding wire PE. The filter capacitors are located between the PE terminals; between the opposite terminals of the first inductor winding L11 and the second inductor winding L12; between the opposite terminals of the third inductor winding L13 and the second inductor winding L12; between the opposite terminals of the fourth inductor winding L14 and the second inductor winding L12; between the opposite terminals of the fifth inductor winding L15 and the second inductor winding L12; and between the opposite terminals of the third inductor winding L13 and the fourth inductor winding L14.The filter capacitor located between the opposite-named terminal of the fourth inductor winding L14 and the opposite-named terminal of the fifth inductor winding L15; the filter capacitor located between the same-named terminal of the first inductor winding L11 and the ground wire PE; the filter capacitor located between the same-named terminal of the second inductor winding L12 and the ground wire PE; the filter capacitor located between the same-named terminal of the third inductor winding L13 and the ground wire PE; the filter capacitor located between the same-named terminal of the first inductor winding L11 and the same-named terminal of the second inductor winding L12; the filter capacitor located between the same-named terminal of the third inductor winding L13 and the same-named terminal of the second inductor winding L12. The filter capacitors are located between the corresponding terminals of the fourth inductor winding L14 and the second inductor winding L12, the fifth inductor winding L15 and the second inductor winding L12, the third inductor winding L13 and the fourth inductor winding L14, the third inductor winding L13 and the fifth inductor winding L15, and the fourth inductor winding L14 and the fifth inductor winding L15.

[0119] based on Figure 5d As can be seen from the circuit structure of the power conversion device 1 shown, Figure 5d The power conversion device 1 shown is also suitable for single-phase input and three-phase output applications, with both the input and output ends using two-stage inductor filtering. Based on the energy flow after the power conversion device 1 is operational, the first inductor winding L11, the second inductor winding L12, the sixth inductor winding L16, and the seventh inductor winding L17 can filter the AC power input from the AC grid, thereby reducing electromagnetic interference and suppressing switching ripple on the input side of the AC / AC circuit 11, preventing switching noise from interfering with grid-side equipment. The second inductor winding L12, the third inductor winding L13, the fourth inductor winding L14, the fifth inductor winding L15, the eighth inductor winding L18, the ninth inductor winding L19, the tenth inductor winding L110, and the eleventh inductor winding L111 can filter the AC power output from the AC / AC circuit 11, resulting in AC power that meets the normal operating noise requirements of the AC load and has lower noise levels. Thus, the first filter inductor L1 and the second filter inductor L2 can achieve the functions of two-stage inductor filtering at the input end and two-stage inductor filtering at the output end in the existing single-phase input and three-phase output AC / AC power supply.

[0120] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current value of the branch where the second inductor winding L12 is located (i.e., the circuit between node J7 and the common terminal in / out of AC / AC circuit 11) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing AC / AC power supply with two-stage inductor filtering at both the input and output ends and single-phase input, it can be known that the current value of the branch where the inductor winding Lin2 corresponding to the second inductor winding L12 is located (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current value of the branch where the second inductor winding L12 is located in the power conversion device 1 provided in this application is significantly lower than the current value of the branch where the corresponding inductor winding Lin2 is located in the prior art. Therefore, the second inductor winding L12 in the power conversion device 1 can use thinner copper wire or cable, and the connection line between node J6 and the common terminal in / out of AC / AC circuit 11 can use thinner cable, thereby greatly reducing the circuit cost of the power conversion device 1.

[0121] In this embodiment, compared to the two-stage input and two-stage output filter inductors of a single-phase input, three-phase output AC / AC power supply in the prior art, the first filter inductor L1 and the second filter inductor L2 reduce one inductor winding and two inductor cores, thereby reducing the size of the power conversion device 1 and lowering its circuit cost. Furthermore, since the second inductor winding L12 is a shared inductor winding for both input and output inductor filtering, and the current flowing through this shared inductor winding is significantly lower than that of the corresponding inductor winding Lin2 in the prior art, the circuit cost of the second inductor winding L12 and its corresponding connecting wires can be effectively reduced, further lowering the circuit cost of the power conversion device 1.

[0122] See Figure 6a , Figure 6a This is another structural schematic diagram of the power conversion device provided in this application. For example... Figure 6a As shown, with Figure 3aCompared to the power conversion device 1 shown, the AC input terminals of the power conversion device 1 further include a third input terminal in3 and a fourth input terminal in4. The first filter inductor L1 further includes a fourth inductor winding L14 and a fifth inductor winding L15. The input terminals of the AC / AC circuit 11 further include a second input terminal in12 and a third input terminal in13. Specifically, the first end of the fourth inductor winding L14 is connected to the third input terminal in3 of the power conversion device 1, and the second end of the fourth inductor winding L14 is connected to the second input terminal in12 of the AC / AC circuit 11. The first end of the fifth inductor winding L15 is connected to the fourth input terminal in4 of the power conversion device 1, and the second end of the fifth inductor winding L15 is connected to the third input terminal in13 of the AC / AC circuit 11. In this application, the first ends of the inductor windings can be terminals with the same name, and correspondingly, the second ends of the inductor windings are all terminals with different names.

[0123] The power conversion device 1 also includes a first filter capacitor C1, a second filter capacitor C2, and a third filter capacitor C3. For a description of the first filter capacitor C1, the second filter capacitor C2, and the third filter capacitor C3, please refer to [link to relevant documentation]. Figure 3b The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0124] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the first input terminal in1 and the grounding wire PE of the power conversion device 1; a filter capacitor located between the third input terminal in3 and the grounding wire PE of the power conversion device 1; a filter capacitor located between the fourth input terminal in4 and the grounding wire PE of the power conversion device 1; a filter capacitor located between the first output terminal out1 and the grounding wire PE of the power conversion device 1; a filter capacitor located between the first input terminal in1 and the second input terminal in2 of the power conversion device 1; a filter capacitor located between the third input terminal in3 and the second input terminal in2 of the power conversion device 1; a filter capacitor located between the fourth input terminal in4 and the second input terminal in2 of the power conversion device 1; a filter capacitor located between the first input terminal in1 and the third input terminal in3 of the power conversion device 1; a filter capacitor located between the first input terminal in1 and the fourth input terminal in4 of the power conversion device 1; a filter capacitor located between the third input terminal in3 and the fourth input terminal in4 of the power conversion device 1; a filter capacitor located between the third input terminal in3 and the fourth input terminal in4 of the power conversion device 1; a filter capacitor located between the third input terminal in3 and the fourth input terminal in4 of the power conversion device 1; a filter capacitor located between the third input terminal in1 ... The filter capacitors are located between the first output terminal out1 and the second output terminal out2 of the power conversion device 1, the filter capacitor between the opposite terminal of the first inductor winding L11 and the grounding line PE, the filter capacitor between the opposite terminal of the second inductor winding L12 and the grounding line PE, the filter capacitor between the opposite terminal of the third inductor winding L13 and the grounding line PE, the filter capacitor between the opposite terminal of the fourth inductor winding L14 and the grounding line PE, the filter capacitor between the opposite terminal of the fifth inductor winding L15 and the grounding line PE, and the filter capacitor between the opposite terminal of the first inductor winding L11 and the grounding line PE. The filter capacitors located between the opposite terminals of the second inductor winding L12, the fourth inductor winding L14, and the fifth inductor winding L15; the filter capacitors located between the opposite terminals of the first inductor winding L11 and the fourth inductor winding L14; and the fifth inductor winding L15.The filter capacitors located between the opposite-named terminals of the second inductor winding L12 and the third inductor winding L13, the filter capacitors located between the same-named terminal of the first inductor winding L11 and the grounding line PE, the filter capacitors located between the same-named terminal of the second inductor winding L12 and the grounding line PE, the filter capacitors located between the same-named terminal of the third inductor winding L13 and the grounding line PE, the filter capacitors located between the same-named terminal of the fourth inductor winding L14 and the grounding line PE, the filter capacitors located between the same-named terminal of the fifth inductor winding L15 and the grounding line PE, and the filter capacitors located between the same-named terminal of the first inductor winding L11 and the same-named terminal of the second inductor winding L12, are listed below. The filter capacitors located between the corresponding terminals of the second inductor winding L12 and the fourth inductor winding L14, the filter capacitors located between the corresponding terminals of the second inductor winding L12 and the fifth inductor winding L15, the filter capacitors located between the corresponding terminals of the first inductor winding L11 and the fourth inductor winding L14, the filter capacitors located between the corresponding terminals of the fourth inductor winding L14 and the fifth inductor winding L15, the filter capacitors located between the corresponding terminals of the first inductor winding L11 and the fifth inductor winding L15, and the filter capacitors located between the corresponding terminals of the second inductor winding L12 and the third inductor winding L13.

[0125] Here, AC / AC circuit 11 can be adopted. Figure 6b The AC / AC circuit 11 shown is as follows: Figure 6bAs shown, the AC / AC circuit 11 includes a first phase bridge arm 111, a second phase bridge arm 112, a third phase bridge arm 113, a fourth phase bridge arm 114, a first bus capacitor Cbus1, a second bus capacitor Cbus2, a first inductor Lin1, a second inductor Lin2, a third inductor Lin3, and a fourth inductor Lout1. The first phase bridge arm 111, the second phase bridge arm 112, the third phase bridge arm 113, and the fourth phase bridge arm 114 are connected in parallel. Specifically, switching transistors Q11 and Q12 are connected in series to form the first phase bridge arm 111, switching transistors Q21 and Q22 are connected in series to form the second phase bridge arm 112, switching transistors Q31 and Q32 are connected in series to form the third phase bridge arm 113, and switching transistors Q41 and Q42 are connected in series to form the fourth phase bridge arm 114. The first bus capacitor Cbus1 and the second bus capacitor Cbus2 are connected in series and then in parallel across the two ends of the first phase bridge arm 111. The series connection point J5 between the first bus capacitor Cbus1 and the second bus capacitor Cbus2 is connected to the common terminal in / out of the AC / AC circuit 11. The midpoint a1 of the first phase bridge arm 111, i.e., the series connection point of switching transistors Q11 and Q12, is connected to the first input terminal in11 of the AC / AC circuit 11 through the first inductor Lin1. The midpoint a2 of the second phase bridge arm 112, i.e., the series connection point of switching transistors Q21 and Q22, is connected to the second input terminal in12 of the AC / AC circuit 11 through the second inductor Lin2. The midpoint a3 of the third phase bridge arm 113, i.e., the series connection point of switching transistors Q31 and Q32, is connected to the third input terminal in13 of the AC / AC circuit 11 through the third inductor Lin3. The midpoint a4 of the fourth phase bridge arm 114, which is the series connection point of switch Q41 and switch Q42, is connected to the first output terminal out11 of AC / AC circuit 11 through the fourth inductor Lout1.

[0126] After the power conversion device 1 starts working, the three-phase AC energy from the AC grid is input into the power conversion device 1 through the first input terminal in1, the third input terminal in3, and the fourth input terminal in4. It flows through the first inductor winding L11, the fourth inductor winding L14, the fifth inductor winding L15, and the second inductor winding L12, and then flows into the AC / AC circuit 11 through the first input terminal in11, the second input terminal in12, the third input terminal in13, and the common terminal in / out. The energy is then rectified by the first phase bridge arm 111, the second phase bridge arm 112, and the third phase bridge arm 113. Clearly, the first inductor winding L11, the second inductor winding L12, the fourth inductor winding L14, and the fifth inductor winding L15 can filter the AC power input from the AC grid, thereby reducing electromagnetic interference from the AC power input from the AC grid and filtering the AC / AC circuit 11 on the grid side. Furthermore, the energy stored in the first bus capacitor Cbus1 and the second bus capacitor Cbus2 through rectification by the aforementioned bridge arms is inverted by the fourth phase bridge arm 114 and the first phase bridge arm 111, and output from the first output terminal out11 and the common terminal in / out of the AC / AC circuit 11. After passing through the third inductor winding L13 and the second inductor winding L12, it flows into the AC load. Clearly, the second inductor winding L12 and the third inductor winding L13 can filter the AC output from the AC / AC circuit 11, obtaining AC power that meets the normal operating noise requirements of the AC load. Therefore, it can be concluded that the first filter inductor L1 can perform the functions of an input filter inductor with four inductor windings and an output filter inductor with two inductor windings in a three-phase input, single-phase output AC / AC power supply in the prior art.

[0127] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current value of the branch containing the second inductor winding L12 (i.e., the circuit between node J1 and node J5) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing three-phase input single-phase output AC / AC power supply, the current value of the branch containing the inductor winding Lin2 (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current flowing through the branch where the second inductor winding L12 is located in the power conversion device 1 provided in this application is significantly lower than the current flowing through the branch where the inductor winding Lin2 is located in the prior art. Therefore, the second inductor winding L12 in the power conversion device 1 can use thinner copper wire or cable, and the connecting line between node J1 and node J5 can be made of thinner cable, thereby greatly reducing the circuit cost of the power conversion device 1.

[0128] In this embodiment, the first filter inductor L1 not only performs the functions of the input filter inductor and output filter inductor in a three-phase input, single-phase output AC / AC power supply in the prior art, but also reduces the size of the power conversion device 1 and its circuit cost compared to the input and output filter inductors in a three-phase input, single-phase output AC / AC power supply in the prior art. Furthermore, since the second inductor winding L12 is a shared inductor winding for both input and output inductor filtering, and the current flowing through this shared inductor winding is significantly lower than the current flowing through the corresponding inductor winding Lin2 in the prior art, the circuit cost of the second inductor winding L12 and its corresponding connecting wires can be effectively reduced, thereby further reducing the circuit cost of the power conversion device 1. Furthermore, since the second inductor winding L2 is a common inductor winding, the second input terminal in2 of the power conversion device 1 is connected to the second output terminal out2. As a result, the third filter capacitor C3 can be equivalent to the filter capacitors Cin3 and Cout3 in the prior art. Therefore, compared with the AC / AC power supply in the prior art, the power conversion device 1 can reduce one filter capacitor, thereby further reducing the circuit cost of the power conversion device 1.

[0129] See Figure 6c , Figure 6c This is another structural schematic diagram of the power conversion device provided in this application. (And...) Figure 6a Compared to the power conversion device 1 shown, Figure 6c The power conversion device 1 shown also includes a second filter inductor L2. Specifically, as... Figure 6c As shown, the second filter inductor L2 includes a sixth inductor winding L16, a seventh inductor winding L17, an eighth inductor winding L18, a ninth inductor winding L19, a tenth inductor winding L110, and a second inductor core.

[0130] The sixth inductor winding L16, the seventh inductor winding L17, the eighth inductor winding L18, the ninth inductor winding L19, and the tenth inductor winding L110 are all wound on the second inductor core. The first end of the first inductor winding L11 is connected to the first input terminal in1 of the power conversion device 1 via the sixth inductor winding L16. The first end of the second inductor winding L12 is connected to the second input terminal in2 and the second output terminal out2 of the power conversion device 1 via the seventh inductor winding L17. The first end of the third inductor winding L13 is connected to the first output terminal out1 of the power conversion device via the eighth inductor winding L18. The first end of the fourth inductor winding L14 is connected to the third input terminal in3 of the power conversion device 1 via the ninth inductor winding L19. The first end of the fifth inductor winding L15 is connected to the fourth input terminal in4 of the power conversion device 1 via the tenth inductor winding L110.

[0131] In this application, the first end of the inductor winding can be a same-named end, and correspondingly, the second end of the inductor winding is a different-named end. For the specific connection relationship between each inductor winding in the first filter inductor L1 and the AC / AC circuit 11, as well as the circuit elements included in the AC / AC circuit 11 and their specific connection relationships, please refer to [link to relevant documentation]. Figure 6a and Figure 6b The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0132] Optionally, the first filter capacitor C1 can also be located between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13, or between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13. Understandably, the position of the first filter capacitor C1 in the power conversion device 1 is diverse, thus making the structure of the power conversion device 1 diverse and highly flexible.

[0133] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the first input terminal in1 of the power conversion device 1 and the ground wire PE; a filter capacitor located between the second input terminal in2 of the power conversion device 1 and the ground wire PE; a filter capacitor located between the third input terminal in3 of the power conversion device 1 and the ground wire PE; a filter capacitor located between the fourth input terminal in4 of the power conversion device 1 and the ground wire PE; a filter capacitor located between the first output terminal out1 of the power conversion device 1 and the ground wire PE; and other filter capacitors connected to each inductor winding of the first filter inductor L1. For the specific locations of the other filter capacitors connected to each inductor winding of the first filter inductor L1, please refer to [link to relevant documentation]. Figure 5c The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0134] based on Figure 6c As can be seen from the circuit structure of the power conversion device 1 shown, Figure 6cThe power conversion device 1 shown is suitable for applications with three-phase input and single-phase output, and both the input and output ends use two-stage inductor filtering. Based on the energy flow after the power conversion device 1 is working, the first inductor winding L11, the second inductor winding L12, the fourth inductor winding L14, the fifth inductor winding L15, the sixth inductor winding L16, the seventh inductor winding L17, the ninth inductor winding L19, and the tenth inductor winding L110 can filter the AC power input from the AC grid to better reduce electromagnetic interference from the AC power input from the AC grid, and can also better suppress the switching ripple on the input side of the AC / AC circuit 11 to prevent switching noise from interfering with the grid-side equipment. The second inductor winding L12, the third inductor winding L13, the seventh inductor winding L17, and the eighth inductor winding L18 can filter the AC power output from the AC / AC circuit 11 to obtain AC power that meets the normal operating noise requirements of the AC load and has lower noise. Thus, the first filter inductor L1 and the second filter inductor L2 can achieve the functions of two-stage inductor filtering at the input end and two-stage inductor filtering at the output end in the existing three-phase input single-phase output AC / AC power supply.

[0135] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current flowing through the branch containing the seventh inductor winding L17 and the second inductor winding L12 (i.e., the circuit between node J6 and the common terminal in / out of AC / AC circuit 11) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing AC / AC power supply with two-stage inductor filtering at both the input and output ends and a three-phase input and single-phase output, the current flowing through the branch corresponding to the seventh inductor winding L17 and the second inductor winding L12 (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current values ​​of the branches containing the second inductor winding L12 and the seventh inductor winding L17 in the power conversion device 1 provided in this application are significantly lower than the current values ​​of the branches containing the corresponding two inductor windings in the prior art. Therefore, the second inductor winding L12 and the seventh inductor winding L17 in the power conversion device 1 can both use thinner copper wires or cables, and the connection lines between node J6 and the common terminals in / out of the AC / AC circuit can both use thinner cables, thereby significantly reducing the circuit cost of the power conversion device 1.

[0136] In this embodiment, compared to the two-stage input and two-stage output filter inductors of a three-phase input, single-phase output AC / AC power supply in the prior art, the first filter inductor L1 and the second filter inductor L2 reduce two inductor windings and two inductor cores, thereby reducing the size of the power conversion device 1 and lowering its circuit cost. Furthermore, since the second inductor winding L12 and the seventh inductor winding L17 are shared inductor windings for both input and output inductor filtering, and the current flowing through the shared inductor winding is significantly lower than that of the corresponding two inductor windings in the prior art, the circuit cost of the second inductor winding L12, the seventh inductor winding L17, and their corresponding connecting wires can be effectively reduced, further lowering the circuit cost of the power conversion device 1.

[0137] See Figure 6d , Figure 6d This is another structural schematic diagram of the power conversion device provided in this application. For example... Figure 6d As shown, with Figure 6c Compared to the power conversion device 1 shown, Figure 6d The second filter inductor L2 shown is Figure 6c The second filter inductor L2 shown is different. Specifically, the second filter inductor L2 includes a sixth inductor winding L16, a seventh inductor winding L17, an eighth inductor winding L18, a ninth inductor winding L19, a tenth inductor winding L110, an eleventh inductor winding L111, and a second inductor core. The sixth inductor winding L16, the seventh inductor winding L17, the eighth inductor winding L18, the ninth inductor winding L19, the tenth inductor winding L110, and the eleventh inductor winding L111 are all wound on the second inductor core. The first end of the first inductor winding L11 is connected to the first input terminal in1 of the power conversion device 1 through the sixth inductor winding L16. The first end of the second inductor winding L12 is connected to the second input terminal in2 of the power conversion device 1 through the seventh inductor winding L17, and the first end of the second inductor winding L12 is connected to the second output terminal out2 of the power conversion device 1 through the eighth inductor winding L18. The first end of the third inductor winding L13 is connected to the first output terminal out1 of the power conversion device 1 through the ninth inductor winding L19. The first end of the fourth inductor winding L14 is connected to the third input terminal in3 of the AC conversion device 1 through the tenth inductor winding L110. The first end of the fifth inductor winding L15 is connected to the fourth input terminal in4 of the AC conversion device through the eleventh inductor winding L111.

[0138] here, Figure 6d For the circuit components and their connections in the power conversion device 1 shown, excluding the second filter inductor L2, please refer to [link to relevant documentation]. Figure 6cThe description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0139] The power conversion device 1 also includes a first filter capacitor C1. For example, the first filter capacitor C1 is located between the second input terminal in2 and the second output terminal out2 of the power conversion device 1. Optionally, the first filter capacitor C1 can also be located between the first input terminal in1 and the first output terminal out1 of the power conversion device 1, or between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13, or between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13. It is understood that the location of the first filter capacitor C1 in the power conversion device 1 is diverse, thus making the structure of the power conversion device 1 diverse and highly flexible.

[0140] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the first input terminal in1 and the grounding line PE of the power conversion device 1; a filter capacitor located between the second input terminal in2 and the grounding line PE of the power conversion device 1; a filter capacitor located between the third input terminal in3 and the grounding line PE of the power conversion device 1; a filter capacitor located between the fourth input terminal in4 and the grounding line PE of the power conversion device 1; a filter capacitor located between the first output terminal out1 and the grounding line PE of the power conversion device 1; a filter capacitor located between the second output terminal out2 and the grounding line PE of the power conversion device 1; a filter capacitor located between the first input terminal in1 and the second output terminal out2 of the power conversion device 1; and a filter capacitor located between the first input terminal in1 and the second output terminal out2 of the power conversion device 1. The filter capacitors are located between the input terminals in2 and in3, the third input terminal in3 and the second input terminal in2 of the power conversion device 1, the fourth input terminal in4 and the second input terminal in2 of the power conversion device 1, the first input terminal in1 and the third input terminal in3 of the power conversion device 1, the first input terminal in1 and the fourth input terminal in3 of the power conversion device 1, the third input terminal in3 and the fourth input terminal in3 of the power conversion device 1, the first output terminal out1 and the second output terminal out2 of the power conversion device 1, and other filter capacitors connected to each inductor winding in the first filter inductor L1. For the specific locations of these other filter capacitors connected to each inductor winding in the first filter inductor L1, please refer to [link to relevant documentation]. Figure 5d The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0141] based on Figure 6d As can be seen from the circuit structure of the power conversion device 1 shown, Figure 6d The power conversion device 1 shown is also suitable for three-phase input and single-phase output applications, with both the input and output ends using two-stage inductor filtering. Based on the energy flow after the power conversion device 1 is operational, the first inductor winding L11, the second inductor winding L12, the fourth inductor winding L14, the fifth inductor winding L15, the sixth inductor winding L16, the seventh inductor winding L17, the tenth inductor winding L110, and the eleventh inductor winding L111 can filter the AC power input from the AC grid, thereby better reducing electromagnetic interference from the AC power input and better suppressing the switching ripple on the input side of the AC / AC circuit 11, preventing switching noise from interfering with the grid-side equipment. The second inductor winding L12, the third inductor winding L13, the eighth inductor winding L18, and the ninth inductor winding L19 can filter the AC power output from the AC / AC circuit 11, obtaining AC power that meets the normal operating noise requirements of the AC load and has lower noise levels. Thus, the first filter inductor L1 and the second filter inductor L2 can achieve the functions of two-stage inductor filtering at the input end and two-stage inductor filtering at the output end in the existing three-phase input single-phase output AC / AC power supply.

[0142] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current value of the branch where the second inductor winding L12 is located (i.e., the circuit between node J7 and the common terminal in / out of AC / AC circuit 11) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing AC / AC power supply with two-stage inductor filtering at both the input and output ends and a three-phase input and single-phase output, it can be known that the current value of the branch where the inductor winding Lin2 corresponding to the second inductor winding L12 is located (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current value of the branch where the second inductor winding L12 is located in the power conversion device 1 provided in this application is significantly lower than the current value of the branch where the corresponding inductor winding Lin2 is located in the prior art. Therefore, the second inductor winding L12 in the power conversion device 1 can use thinner copper wire or cable, and the connection line between node J7 and the common terminal in / out of AC / AC circuit 11 can use thinner cable, thereby greatly reducing the circuit cost of the power conversion device 1.

[0143] In this embodiment, compared to the two-stage input and two-stage output filter inductors of a three-phase input, single-phase output AC / AC power supply in the prior art, the first filter inductor L1 and the second filter inductor L2 reduce one inductor winding and two inductor cores, thereby reducing the size of the power conversion device 1 and lowering its circuit cost. Furthermore, since the second inductor winding L12 is a shared inductor winding for both input and output inductor filtering, and the current flowing through this shared inductor winding is significantly lower than that of the corresponding inductor winding Lin2 in the prior art, the circuit cost of the second inductor winding L12 and its corresponding connecting wires can be effectively reduced, further lowering the circuit cost of the power conversion device 1.

[0144] See Figure 7a , Figure 7a This is another structural schematic diagram of the power conversion device provided in this application. For example... Figure 7a As shown, with Figure 5a Compared to the power conversion device 1 shown, the AC input terminals of the power conversion device 1 further include a third input terminal in3 and a fourth input terminal in4. The first filter inductor L1 further includes a sixth inductor winding L16 and a seventh inductor winding L17. The input terminals of the AC / AC circuit 11 further include a second input terminal in12 and a third input terminal in13. Specifically, the first end of the sixth inductor winding L16 is connected to the third input terminal in3 of the power conversion device 1, and the second end of the sixth inductor winding L16 is connected to the second input terminal in12 of the AC / AC circuit 11. The first end of the seventh inductor winding L17 is connected to the fourth input terminal in4 of the power conversion device 1, and the second end of the seventh inductor winding L17 is connected to the third input terminal in13 of the AC / AC circuit 11. In this application, the first ends of the inductor windings can be terminals with the same name, and correspondingly, the second ends of the inductor windings are all terminals with different names.

[0145] The power conversion device 1 further includes a first filter capacitor C1, a second filter capacitor C2, and a third filter capacitor C3. For example, the first filter capacitor C1 is located between the first input terminal in1 and the first output terminal out1 of the power conversion device 1; the second filter capacitor C2 is located between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13; and the third filter capacitor C3 is located between the second input terminal in2 of the power conversion device 1 and the ground wire PE. Optionally, the first filter capacitor C1 may also be located between the third input terminal in3 and the third output terminal out3 of the power conversion device 1, or between the fourth input terminal in4 and the fourth output terminal out4 of the power conversion device 1. Optionally, the second filter capacitor C2 may also be located between the opposite-named terminal of the sixth inductor winding L16 and the opposite-named terminal of the fourth inductor winding L14, or between the opposite-named terminal of the seventh inductor winding L17 and the opposite-named terminal of the fifth inductor winding L15.

[0146] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the first input terminal in1 of the power conversion device 1 and the grounding line PE; a filter capacitor located between the third input terminal in3 of the power conversion device 1 and the grounding line PE; a filter capacitor located between the fourth input terminal in4 of the power conversion device 1 and the grounding line PE; a filter capacitor located between the first output terminal out1 of the power conversion device 1 and the grounding line PE; and a filter capacitor located between the third output terminal out3 of the power conversion device 1 and the grounding line PE. The filter capacitors located between the fourth output terminal out4 of the power conversion device 1 and the ground wire PE; the filter capacitors located between the first input terminal in1 and the second input terminal in2 of the power conversion device 1; the filter capacitors located between the third input terminal in3 and the second input terminal in2 of the power conversion device 1; the filter capacitors located between the fourth input terminal in4 and the second input terminal in2 of the power conversion device 1; the filter capacitors located between the first input terminal in1 and the third input terminal in3 of the power conversion device 1; the filter capacitors located between the first input terminal in1 and the fourth input terminal in4 of the power conversion device 1; the filter capacitors located between the third input terminal in3 and the fourth input terminal in4 of the power conversion device 1; and the filter capacitors located between the first output terminal out4 of the power conversion device 1. The filter capacitor between ut1 and the second output terminal out2; the filter capacitor between the third output terminal out3 and the second output terminal out2 of the power conversion device 1; the filter capacitor between the fourth output terminal out4 and the second output terminal out2 of the power conversion device 1; the filter capacitor between the first output terminal out1 and the third output terminal out3 of the power conversion device 1; the filter capacitor between the first output terminal out1 and the fourth output terminal out4 of the power conversion device 1; the filter capacitor between the third output terminal out3 and the fourth output terminal out4 of the power conversion device 1; the filter capacitor between the opposite-name terminal of the sixth inductor winding L16 and the ground wire PE; and the filter capacitor between the opposite-name terminal of the seventh inductor winding L17. The filter capacitor between the ground wire PE, the filter capacitor between the opposite terminal of the sixth inductor winding L16 and the opposite terminal of the seventh inductor winding L17, the filter capacitor between the opposite terminal of the seventh inductor winding L17 and the opposite terminal of the second inductor winding L12, the filter capacitor between the opposite terminal of the sixth inductor winding L16 and the opposite terminal of the second inductor winding L12, the filter capacitor between the opposite terminal of the seventh inductor winding L17 and the opposite terminal of the first inductor winding L11, the filter capacitor between the opposite terminal of the sixth inductor winding L16 and the opposite terminal of the first inductor winding L11, and other filter capacitors connected to the other inductor windings of the first filter inductor L1 other than the sixth inductor winding L16 and the seventh inductor winding L17.For details on the specific locations of the other filter capacitors connected to the other inductor windings of the first filter inductor L1, excluding the sixth inductor winding L16 and the seventh inductor winding L17, please refer to the following. Figure 5a The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0147] Here, AC / AC circuit 11 can be adopted. Figure 7b The AC / AC circuit 11 shown is as follows: Figure 7b As shown, the AC / AC circuit 11 includes a first phase bridge arm 111, a second phase bridge arm 112, a third phase bridge arm 113, a fourth phase bridge arm 114, a fifth phase bridge arm 115, a sixth phase bridge arm 116, a first bus capacitor Cbus1, a second bus capacitor Cbus2, a first inductor Lin1, a second inductor Lin2, a third inductor Lin3, a fourth inductor Lout1, a fifth inductor Lout2, and a sixth inductor Lout3. The first phase bridge arms 111, 112, 113, 114, 115, and 116 are connected in parallel. Specifically, switching transistors Q51 and Q52 are connected in series to form the fifth phase bridge arm 115, and switching transistors Q61 and Q62 are connected in series to form the sixth phase bridge arm 116. The midpoint a5 of the fifth phase bridge arm 115, i.e., the series connection of switching transistors Q51 and Q52, is connected to the second output terminal out12 of the AC / AC circuit 11 via the fifth inductor Lout2. The midpoint a6 of the sixth phase bridge arm 116, i.e., the series connection of switching transistors Q61 and Q62, is connected to the third output terminal out13 of the AC / AC circuit 11 via the sixth inductor Lout3. For a description of the other circuit elements in the AC / AC circuit 11 besides the fifth phase bridge arm 115 and the sixth phase bridge arm 116, please refer to [link to description]. Figure 6b The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0148] After the power conversion device 1 starts working, the three-phase AC energy from the AC grid is input into the power conversion device 1 through its first input terminal in1, second input terminal in2, third input terminal in3, and fourth input terminal in4. The energy flows through the first inductor winding L11, the second inductor winding L12, the sixth inductor winding L16, and the seventh inductor winding L17, and then flows into the AC / AC circuit 11 through its first input terminal in11, common terminal in / out, second input terminal in12, and third input terminal in13. The energy is then rectified by the first phase bridge arm 111, the second phase bridge arm 112, and the third phase bridge arm 113. Clearly, the first inductor winding L11, the second inductor winding L12, the sixth inductor winding L16, and the seventh inductor winding L17 can filter the AC power input from the AC grid, reducing electromagnetic interference and suppressing switching ripple on the input side of the AC / AC circuit 11, preventing switching noise from interfering with the grid-side equipment. Furthermore, the energy stored in the first bus capacitor Cbus1 and the second bus capacitor Cbus2 through the rectification of the aforementioned bridge arms is inverted by the fourth phase bridge arm 114, the fifth phase bridge arm 115, and the sixth phase bridge arm 116, and then output from the common terminal in / out, the first output terminal out11, the second output terminal out12, and the third output terminal out13 of the AC / AC circuit 11, respectively. This energy then flows into the AC load through the second inductor winding L12, the third inductor winding L13, the fourth inductor winding L14, and the fifth inductor winding L15. Clearly, the second inductor winding L12, the third inductor winding L13, the fourth inductor winding L14, and the fifth inductor winding L15 can filter the AC output from the AC / AC circuit 11, obtaining AC power that meets the normal operating noise requirements of the AC load. Therefore, it can be concluded that the first filter inductor L1 can realize the functions of an input filter inductor with 4 inductor windings and an output filter inductor with 4 inductor windings in a three-phase input and three-phase output AC / AC power supply in the prior art.

[0149] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current value of the branch containing the second inductor winding L12 (i.e., the circuit between node J1 and node J5) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing three-phase input and three-phase output AC / AC power supply, the current value of the branch containing the inductor winding Lin2 (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current flowing through the branch where the second inductor winding L12 is located in the power conversion device 1 provided in this application is significantly lower than the current flowing through the branch where the inductor winding Lin2 is located in the prior art. Therefore, the second inductor winding L12 in the power conversion device 1 can use thinner copper wire or cable, and the connecting line between node J1 and node J5 can be made of thinner cable, thereby greatly reducing the circuit cost of the power conversion device 1.

[0150] In this embodiment, the first filter inductor L1 not only performs the functions of the input and output filter inductors in a three-phase input, three-phase output AC / AC power supply in the prior art, but also reduces the size of the power conversion device 1 and its circuit cost compared to the input and output filter inductors in a three-phase input, three-phase output AC / AC power supply in the prior art. Furthermore, since the second inductor winding L12 is a shared inductor winding for both input and output inductor filtering, and the current flowing through this shared inductor winding is significantly lower than the current flowing through the corresponding inductor winding Lin2 in the prior art, the circuit cost of the second inductor winding L12 and its corresponding connecting wires can be effectively reduced, thereby further reducing the circuit cost of the power conversion device 1. Furthermore, since the second inductor winding L2 is a common inductor winding, the second input terminal in2 of the power conversion device 1 is connected to the second output terminal out2. As a result, the third filter capacitor C3 can be equivalent to the filter capacitors Cin3 and Cout3 in the prior art. Therefore, compared with the AC / AC power supply in the prior art, the power conversion device 1 can reduce one filter capacitor, thereby further reducing the circuit cost of the power conversion device 1.

[0151] See Figure 7c , Figure 7c This is another structural schematic diagram of the power conversion device provided in this application. (And...) Figure 7a Compared to the power conversion device 1 shown, Figure 7c The power conversion device 1 shown also includes a second filter inductor L2. Specifically, as... Figure 7cAs shown, the second filter inductor L2 includes an eighth inductor winding L18, a ninth inductor winding L19, a tenth inductor winding L110, an eleventh inductor winding L111, a twelfth inductor winding L112, a thirteenth inductor winding L113, a fourteenth inductor winding L114, and a second inductor core.

[0152] The eighth inductor winding L18, the ninth inductor winding L19, the tenth inductor winding L110, the eleventh inductor winding L111, the twelfth inductor winding L112, the thirteenth inductor winding L113, and the fourteenth inductor winding L114 are all wound on the second inductor core. The first end of the first inductor winding L11 is connected to the first input terminal in1 of the power conversion device 1 through the eighth inductor winding L18. The first end of the second inductor winding L12 is connected to the second input terminal in2 and the second output terminal out2 of the power conversion device 1 through the ninth inductor winding L19. The first end of the third inductor winding L13 is connected to the first output terminal out1 of the power conversion device 1 through the tenth inductor winding L110. The first end of the fourth inductor winding L14 is connected to the third output terminal out3 of the power conversion device 1 through the eleventh inductor winding L111. The first end of the fifth inductor winding L15 is connected to the fourth output terminal out4 of the power conversion device 1 through the twelfth inductor winding L112. The first end of the sixth inductor winding L16 is connected to the third input terminal in3 of the power conversion device 1 through the thirteenth inductor winding L113, and the first end of the seventh inductor winding L17 is connected to the fourth input terminal in4 of the power conversion device 1 through the fourteenth inductor winding L114.

[0153] In this application, the first end of the inductor winding can be a same-named end, and correspondingly, the second end of the inductor winding is a different-named end. For the specific connection relationship between each inductor winding in the first filter inductor L1 and the AC / AC circuit 11, as well as the circuit elements included in the AC / AC circuit 11 and their specific connection relationships, please refer to [link to relevant documentation]. Figure 7a and Figure 7b The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0154] Optionally, the first filter capacitor C1 may also be located between the third input terminal in3 and the third output terminal out3 of the power conversion device 1, or between the fourth input terminal in4 and the fourth output terminal out4 of the power conversion device 1, or between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13, or between the opposite-named terminal of the sixth inductor winding L16 and the opposite-named terminal of the fourth inductor winding L14, or between the opposite-named terminal of the seventh inductor winding L17 and the opposite-named terminal of the fifth inductor winding L15, or between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13, or between the same-named terminal of the sixth inductor winding L16 and the same-named terminal of the fourth inductor winding L14, or between the same-named terminal of the seventh inductor winding L17 and the same-named terminal of the fifth inductor winding L15. It is understandable that the location of the first filter capacitor C1 in the power conversion device 1 varies, which makes the structure of the power conversion device 1 diverse and highly flexible.

[0155] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately increase the filter capacitor. For example, the power conversion device 1 may further include at least one of the following filter capacitors: a filter capacitor located between the third input terminal in3 of the power conversion device 1 and the grounding wire PE; a filter capacitor located between the fourth input terminal in4 of the power conversion device 1 and the grounding wire PE; a filter capacitor located between the first output terminal out1 and the third output terminal out3 of the power conversion device 1; a filter capacitor located between the first output terminal out1 and the fourth output terminal out4 of the power conversion device 1; a filter capacitor located between the third output terminal out3 and the fourth output terminal out4 of the power conversion device 1; a filter capacitor located between the second output terminal out2 and the third output terminal out3 of the power conversion device 1; a filter capacitor located between the second output terminal out2 and the fourth output terminal out4 of the power conversion device 1; a filter capacitor located between the opposite-named terminal of the seventh inductor winding L17 and the opposite-named terminal of the first inductor winding L11; a filter capacitor located between the opposite-named terminal of the sixth inductor winding L16 and the opposite-named terminal of the first inductor winding L11; a filter capacitor located between the opposite-named terminal of the sixth inductor winding L16 and the seventh inductor winding L11; and a filter capacitor located between the opposite-named terminal of the sixth inductor winding L17 and the seventh inductor winding L11. The filter capacitors between the opposite terminals of inductor winding L17, between the opposite terminals of the seventh inductor winding L17 and the second inductor winding L12, between the opposite terminals of the sixth inductor winding L16 and the second inductor winding L12, between the same terminal of the seventh inductor winding L17 and the same terminal of the first inductor winding L11, between the same terminal of the sixth inductor winding L16 and the same terminal of the first inductor winding L11, and between the same terminal of the sixth inductor winding L16 and the seventh inductor winding L12... The filter capacitors between the corresponding terminals of L17, the filter capacitors between the corresponding terminals of the seventh inductor winding L17 and the second inductor winding L12, the filter capacitors between the corresponding terminals of the sixth inductor winding L16 and the second inductor winding L12, and other filter capacitors connected to the input and output terminals other than the third input terminal in3 and the fourth input terminal in4 of the power conversion device 1, and other filter capacitors connected to the other inductor windings of the first filter inductor L1 other than the sixth inductor winding L16 and the seventh inductor winding L17. For the specific locations of the other filter capacitors connected to the input and output terminals other than the third input terminal in3 and the fourth input terminal in4 of the power conversion device 1, and the other filter capacitors connected to the other inductor windings of the first filter inductor L1 other than the sixth inductor winding L16 and the seventh inductor winding L17, please refer to [link to relevant documentation]. Figure 5c The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0156] based on Figure 7cAs can be seen from the circuit structure of the power conversion device 1 shown, Figure 7c The power conversion device 1 shown is suitable for three-phase input and three-phase output applications, with both the input and output ends using two-stage inductor filtering. Based on the energy flow after the power conversion device 1 is in operation, it can be seen that the first inductor winding L11, the second inductor winding L12, the sixth inductor winding L16, the seventh inductor winding L17, the eighth inductor winding L18, the ninth inductor winding L19, the thirteenth inductor winding L113, and the fourteenth inductor winding L114 can filter the AC power input from the AC grid, thereby better reducing the electromagnetic interference of the AC power input from the AC grid. It can also better suppress the switching ripple on the input side of the AC / AC circuit 11, preventing switching noise from interfering with the grid-side equipment. The second inductor winding L12, the third inductor winding L13, the fourth inductor winding L14, the fifth inductor winding L15, the ninth inductor winding L19, the tenth inductor winding L110, the eleventh inductor winding L111, and the twelfth inductor winding L112 can filter the AC output of the AC / AC circuit 11, obtaining AC power that meets the normal operating noise requirements of the AC load and has lower noise. Therefore, the first filter inductor L1 and the second filter inductor L2 can achieve the functions of two-stage inductor filtering at the input and two-stage inductor filtering at the output in a three-phase input, three-phase output AC / AC power supply in the prior art.

[0157] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current flowing through the branch containing the ninth inductor winding L19 and the second inductor winding L12 (i.e., the circuit between node J8 and the common terminal in / out of AC / AC circuit 11) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing AC / AC power supply with two-stage inductor filtering at both the input and output ends, and a three-phase input and three-phase output, the current flowing through the branch corresponding to the ninth inductor winding L19 and the second inductor winding L12 (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current values ​​of the branches containing the ninth inductor winding L19 and the second inductor winding L12 in the power conversion device 1 provided in this application are significantly lower than the current values ​​of the corresponding branches containing the two inductor windings in the prior art. Therefore, the ninth inductor winding L19 and the second inductor winding L12 in the power conversion device 1 can both use thinner copper wires or cables, and the connection lines between node J8 and the common terminals in / out of the AC / AC circuit can both use thinner cables, thereby significantly reducing the circuit cost of the power conversion device 1.

[0158] In this embodiment, compared to the two-stage input and two-stage output filter inductors of a three-phase input, three-phase output AC / AC power supply in the prior art, the first filter inductor L1 and the second filter inductor L2 reduce two inductor windings and two inductor cores, thereby reducing the size of the power conversion device 1 and lowering its circuit cost. Furthermore, since the ninth inductor winding L19 and the second inductor winding L12 are shared inductor windings for both input and output inductor filtering, and the current flowing through the shared inductor winding is significantly lower than that of the corresponding two inductor windings in the prior art, the circuit cost of the ninth inductor winding L19, the second inductor winding L12, and their corresponding connecting wires can be effectively reduced, further lowering the circuit cost of the power conversion device 1.

[0159] See Figure 7d , Figure 7d This is another structural schematic diagram of the power conversion device provided in this application. For example... Figure 7d As shown, with Figure 7c Compared to the power conversion device 1 shown, Figure 7d The second filter inductor L2 shown is Figure 7cThe second filter inductor L2 shown is different. Specifically, the second filter inductor L2 includes an eighth inductor winding L18, a ninth inductor winding L19, a tenth inductor winding L110, an eleventh inductor winding L111, a twelfth inductor winding L112, a thirteenth inductor winding L113, a fourteenth inductor winding L114, a fifteenth inductor winding L115, and a second inductor core. Among them, the eighth inductor winding L18, the ninth inductor winding L19, the tenth inductor winding L110, the eleventh inductor winding L111, the twelfth inductor winding L112, the thirteenth inductor winding L113, the fourteenth inductor winding L114, and the fifteenth inductor winding L115 are all wound on the second inductor core. The first end of the first inductor winding L11 is connected to the first input terminal in1 of the power conversion device 1 via the eighth inductor winding L18. The first end of the second inductor winding L12 is connected to the second input terminal in2 of the power conversion device 1 via the ninth inductor winding L19. The first end of the second inductor winding L12 is connected to the second output terminal out2 of the power conversion device 1 via the tenth inductor winding L110. The first end of the third inductor winding L13 is connected to the first output terminal out1 of the power conversion device 1 via the eleventh inductor winding L111. The first end of the fourth inductor winding L14 is connected to the third output terminal out3 of the power conversion device 1 via the twelfth inductor winding L112. The first end of the fifth inductor winding L15 is connected to the fourth output terminal out4 of the power conversion device 1 via the thirteenth inductor winding L113. The first end of the sixth inductor winding L16 is connected to the third input terminal in3 of the power conversion device 1 through the fourteenth inductor winding L114, and the first end of the seventh inductor winding L15 is connected to the fourth input terminal in4 of the power conversion device 1 through the fifteenth inductor winding L115.

[0160] here, Figure 7d For the circuit components and their connections in the power conversion device 1 shown, excluding the second filter inductor L2, please refer to [link to relevant documentation]. Figure 7c The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0161] The power conversion device 1 also includes a first filter capacitor C1. For example, the first filter capacitor C1 is located between the second input terminal in2 and the second output terminal out2 of the power conversion device 1. Optionally, the first filter capacitor C1 may also be located between the first input terminal in1 and the first output terminal out1 of the power conversion device 1, or between the third input terminal in3 and the third output terminal out3 of the power conversion device 1, or between the fourth input terminal in4 and the fourth output terminal out4 of the power conversion device 1, or between the opposite-named terminal of the first inductor winding L11 and the opposite-named terminal of the third inductor winding L13, or between the opposite-named terminal of the sixth inductor winding L16 and the opposite-named terminal of the fourth inductor winding L14, or between the opposite-named terminal of the seventh inductor winding L17 and the opposite-named terminal of the fifth inductor winding L15, or between the same-named terminal of the first inductor winding L11 and the same-named terminal of the third inductor winding L13, or between the same-named terminal of the sixth inductor winding L16 and the same-named terminal of the fourth inductor winding L14, or between the same-named terminal of the seventh inductor winding L17 and the same-named terminal of the fifth inductor winding L15. It is understandable that the location of the first filter capacitor C1 in the power conversion device 1 varies, which makes the structure of the power conversion device 1 diverse and highly flexible.

[0162] To better achieve the filtering effect on the input and output current of the power conversion device 1, the power conversion device 1 can also appropriately add filter capacitors. For example, the power conversion device 1 can also add at least one of the following filter capacitors: a filter capacitor located between the third input terminal in3 of the power conversion device 1 and the ground wire PE; a filter capacitor located between the fourth input terminal in4 of the power conversion device 1 and the ground wire PE; a filter capacitor located between the third input terminal in3 of the power conversion device 1 and the second input terminal in2; a filter capacitor located between the fourth input terminal in4 of the power conversion device 1 and the second input terminal in2; and a filter capacitor located between the fourth input terminal in4 of the power conversion device 1 and the third input terminal in3. The filter capacitors located between the first input terminal in1 and the third input terminal in3 of the power conversion device 1, the filter capacitors located between the first input terminal in1 and the fourth input terminal in3 of the power conversion device 1, the filter capacitors located between the third input terminal in3 and the fourth input terminal in3 of the power conversion device 1, and other filter capacitors connected to the other input terminals and output terminals of the power conversion device 1 other than the third input terminal in3 and the fourth input terminal in4, and other filter capacitors connected to the other inductor windings of the first filter inductor L1 other than the sixth inductor winding L16 and the seventh inductor winding L17. For the specific locations of the other filter capacitors connected to the other input terminals and output terminals of the power conversion device 1 other than the third input terminal in3 and the fourth input terminal in4, and the other filter capacitors connected to the other inductor windings of the first filter inductor L1 other than the sixth inductor winding L16 and the seventh inductor winding L17, please refer to [link to relevant documentation]. Figure 5d The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0163] based on Figure 7d As can be seen from the circuit structure of the power conversion device 1 shown, Figure 7dThe power conversion device 1 shown is also suitable for three-phase input and three-phase output applications, with both the input and output ends using two-stage inductor filtering. Based on the energy flow after the power conversion device 1 is operational, the first inductor winding L11, the second inductor winding L12, the sixth inductor winding L16, the seventh inductor winding L17, the eighth inductor winding L18, the ninth inductor winding L19, the fourteenth inductor winding L114, and the fifteenth inductor winding L115 can filter the AC power input from the AC grid, thereby better reducing electromagnetic interference from the AC power input from the AC grid. They can also better suppress the switching ripple on the input side of the AC / AC circuit 11, preventing switching noise from interfering with the grid-side equipment. The second inductor winding L12 to the fifth inductor winding L15, and the tenth inductor winding L110 to the thirteenth inductor winding L113 can filter the AC power output from the AC / AC circuit 11, obtaining AC power that meets the normal operating noise requirements of the AC load and has lower noise levels. Thus, the first filter inductor L1 and the second filter inductor L2 can achieve the functions of two-stage inductor filtering at the input end and two-stage inductor filtering at the output end in the existing three-phase input and three-phase output AC / AC power supply.

[0164] Furthermore, assuming the input current and output current of power conversion device 1 are I1 and I2 respectively, based on the energy flow direction in power conversion device 1, the current value of the branch where the second inductor winding L12 is located (i.e., the circuit between node J9 and the common terminal in / out of AC / AC circuit 11) is I1-I2. Similarly, based on the circuit structure and energy flow direction of the existing AC / AC power supply with two-stage inductor filtering at both the input and output ends, and a three-phase input and three-phase output, it can be known that the current value of the branch where the inductor winding Lin2 corresponding to the second inductor winding L12 is located (i.e., the circuit between the input terminal inN of the AC / AC power supply and the common terminal in / out of the AC / AC circuit) is I1. Obviously, the current value of the branch where the second inductor winding L12 is located in the power conversion device 1 provided in this application is significantly lower than the current value of the branch where the corresponding inductor winding Lin2 is located in the prior art. Therefore, the second inductor winding L12 in the power conversion device 1 can use thinner copper wire or cable, and the connection line between node J9 and the common terminal in / out of AC / AC circuit 11 can use thinner cable, thereby greatly reducing the circuit cost of the power conversion device 1.

[0165] In this embodiment, compared to the two-stage input and two-stage output filter inductors of a three-phase input, three-phase output AC / AC power supply in the prior art, the first filter inductor L1 and the second filter inductor L2 reduce one inductor winding and two inductor cores, thereby reducing the size of the power conversion device 1 and lowering its circuit cost. Furthermore, since the second inductor winding L12 is a shared inductor winding for both input and output inductor filtering, and the current flowing through this shared inductor winding is significantly lower than that of the corresponding inductor winding Lin2 in the prior art, the circuit cost of the second inductor winding L12 and its corresponding connecting wires can be effectively reduced, further lowering the circuit cost of the power conversion device 1.

[0166] It should be noted that the number of filter inductors included in the power conversion device 1 in this application can be adjusted according to the filtering requirements in the actual application scenario, and this application does not impose any restrictions on this. Furthermore, this application uses the example of single-stage or two-stage filtering inductors at the input and output ends of the power conversion device 1 as an example. When both the input and output filter inductors in the power conversion device 1 are three-stage or higher filtering, the specific circuit structure and working principle of the filter inductors and capacitors in the power conversion device 1 can be derived from a power conversion device 1 where both the input and output filter inductors are two-stage filtering, and this application will not elaborate further on this. The circuit structure of the AC / AC circuit in this application can be... Figures 3a to 7d In addition to the non-isolated AC / AC circuit topology shown, other non-isolated AC / AC circuit topologies or isolated AC / AC circuit topologies may also be used, and this application does not impose any restrictions on them.

[0167] Furthermore, the first filter inductor L1 in this application can also adopt a circuit structure in which the input and output inductor windings share only a magnetic core. Specifically, when the power conversion device 1 has a single-phase input and single-phase output circuit structure, the first filter inductor L1 includes four inductor windings and a first magnetic core. Two of the four inductor windings are connected between the AC input terminal of the power conversion device 1 and the input terminal of the AC / AC circuit 11, and the other two inductor windings are connected between the AC output terminal of the power conversion device 1 and the output terminal of the AC / AC circuit 11. All four inductor windings are wound on the first magnetic core. Obviously, the power conversion device 1 with the first filter inductor L1 sharing only a magnetic core and having single-phase input and single-phase output, compared with the single-phase input and single-phase output AC / AC power supply in the prior art, can reduce one inductor core, thereby reducing the circuit cost of the power conversion device 1. When the power conversion device 1 has a three-phase input and single-phase output circuit structure, the first filter inductor L1 includes six inductor windings and a first magnetic core. Four of the six inductor windings are connected between the AC input terminal of the power conversion device 1 and the input terminal of the AC / AC circuit 11, while the other two inductor windings are connected between the AC output terminal of the power conversion device 1 and the output terminal of the AC / AC circuit 11. All six inductor windings are wound on the first magnetic core. Clearly, by using a power conversion device 1 with a shared magnetic core and a three-phase input and single-phase output configuration, the first filter inductor L1 reduces the number of inductor cores by one compared to existing three-phase input and single-phase output AC / AC power supplies, thereby lowering the circuit cost of the power conversion device 1. When the power conversion device 1 has a three-phase input and three-phase output circuit structure, the first filter inductor L1 includes eight inductor windings and a first magnetic core. Four of the eight inductor windings are connected between the AC input terminal of the power conversion device 1 and the input terminal of the AC / AC circuit 11, while the other four are connected between the AC output terminal of the power conversion device 1 and the output terminal of the AC / AC circuit 11. All eight inductor windings are wound on the first magnetic core. Clearly, by using a power conversion device 1 with a single-phase input and single-phase output and a shared magnetic core, the first filter inductor L1 reduces the number of inductor cores compared to the existing three-phase input and three-phase output AC / AC power supplies, thereby lowering the circuit cost of the power conversion device 1.

[0168] When the power conversion device 1 provided in this application is a UPS, the UPS may further include a bypass switch. When the UPS has a single-phase input and single-phase output circuit structure, the bypass switch may be located between the same-name terminal of the first inductor winding L11 and the same-name terminal of the third inductor winding L13, or between the opposite-name terminal of the first inductor winding L11 and the opposite-name terminal of the third inductor winding L13. When the UPS has a three-phase input and three-phase output circuit structure (such as...) Figure 7aWhen the power conversion device 1) is shown, the UPS includes three bypass switches: a first bypass switch, a second bypass switch, and a third bypass switch. The first bypass switch is located between the same-name terminal of the first inductor winding L11 and the same-name terminal of the third inductor winding L13, or between the opposite-name terminal of the first inductor winding L11 and the opposite-name terminal of the third inductor winding L13. The second bypass switch is located between the same-name terminal of the fourth inductor winding L14 and the same-name terminal of the sixth inductor winding L16, or between the opposite-name terminal of the fourth inductor winding L14 and the opposite-name terminal of the sixth inductor winding L16. The third bypass switch is located between the same-name terminal of the fifth inductor winding L15 and the same-name terminal of the seventh inductor winding L17, or between the opposite-name terminal of the fifth inductor winding L15 and the opposite-name terminal of the seventh inductor winding L17. Understandably, when the AC / AC circuit in a UPS fails, the UPS can control the bypass switch to close, allowing the AC power input from the AC mains to be directly output to the AC load through the bypass switch, thereby powering the AC load. This not only improves the stability of the UPS during operation but also increases its efficiency.

[0169] Optionally, the UPS may also include an energy storage unit connected across the bus capacitor in the AC / AC circuit 11. For example, when the UPS has a single-phase input and single-phase output circuit structure (such as...), Figure 3b When the power conversion device 1 shown is used, the energy storage unit is connected across the first bus capacitor Cbus1. When the UPS has a single-phase input and three-phase output circuit structure (such as...), Figure 5b When the power conversion device 1 shown is connected, the energy storage unit is connected across the two ends formed by the series connection of the first bus capacitor Cbus1 and the second bus capacitor Cbus2. It can be understood that when the AC power grid no longer outputs AC power, the UPS can use the DC / AC circuit in the AC / AC circuit 11 to invert the DC power output from the energy storage unit into AC power, thereby achieving uninterrupted power supply to the AC load.

[0170] When the power conversion device 1 provided in this application is an inverter Figures 3a to 7d The power conversion device 1 shown has a bidirectional AC input terminal, and correspondingly, at least two of its AC input terminals are also bidirectional. The AC / AC circuit 11 has a bidirectional input terminal, and correspondingly, the common terminal and at least one input terminal of the AC / AC circuit 11 are also bidirectional. Here, a bidirectional input terminal is a terminal that can function as both an input and an output. The power conversion device also includes a DC / DC circuit and a first DC input terminal. The AC / AC circuit 11 includes both AC / DC and DC / AC circuits; please refer to [link to relevant documentation] for details. Figure 8 The power conversion device shown. For example... Figure 8 As shown, with Figure 3a Compared to the power conversion device 1 shown, the power conversion device 1 further includes first DC input terminals inDC1 and inDC2, and a DC / DC circuit 12. The AC / AC circuit 11 includes an AC / DC circuit and a DC / AC circuit. The first DC input terminals inDC1 and inDC2 of the power conversion device 1 are connected to the photovoltaic string. The DC input terminals in31 and in32 of the DC / DC circuit 12 are respectively connected to the first DC input terminals inDC1 and inDC2 of the power conversion device 1. The DC output terminals out31 and out32 of the DC / DC circuit 12 are respectively connected to the DC terminals DC21 and DC22 of the AC / DC circuit. The DC output terminals out31 and out32 of the DC / DC circuit 12 are respectively connected to the DC input terminals inDC21 and inDC22 of the DC / AC circuit. The two AC terminals of the AC / DC circuit serve as the first input terminal in11 and the common terminal in / out of the AC / AC circuit 11, respectively. The two AC output terminals of the DC / AC circuit serve as the common terminal in / out and the first output terminal out11 of the AC / AC circuit 11, respectively. For a description of the first filter inductor L1 in the inverter, please refer to [link to relevant documentation]. Figure 3a The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0171] For example, when the power conversion device 1 has a single-phase input and single-phase output circuit structure and the AC / AC circuit 11 is... Figure 3b When the AC / AC circuit 11 is shown, the AC / DC circuit is... Figure 3b The diagram shows the circuit structure formed by the first inductor Lin1 connected between the midpoint a1 of the first phase bridge arm 111 and the first input terminal in11 of the AC / AC circuit 11, and the first phase bridge arm 111, the first bus capacitor Cbus1, and the second phase bridge arm 112 connected in parallel. The two ends of the first bus capacitor Cbus1 correspond to the DC terminals DC21 and DC22 of the AC / DC circuit, respectively. The DC / AC circuit is... Figure 3b The circuit structure shown consists of the second inductor Lout1 connected between the midpoint a3 of the third phase bridge arm 113 and the first output terminal out11 of the AC / AC circuit 11, and the second phase bridge arm 112 and the third phase bridge arm 113 connected in parallel. The two ends formed by the parallel connection of the second phase bridge arm 112 and the third phase bridge arm 113 correspond to the DC input terminals inDC21 and inDC22 of the DC / AC circuit, respectively.

[0172] When the power conversion device 1 has a single-phase input and three-phase output circuit structure and the AC / AC circuit 11 is Figure 5b When the AC / AC circuit 11 is shown, the AC / DC circuit is... Figure 5bThe circuit structure shown consists of the branch containing the two bus capacitors connected in series, the first phase bridge arm 111 and the second phase bridge arm 112 connected in parallel, the first inductor Lin1 connected between the midpoint a1 of the first phase bridge arm 111 and the first input terminal in11 of the AC / AC circuit 11, and the second inductor Lout1 connected between the midpoint a2 of the second phase bridge arm 112 and the first output terminal out11 of the AC / AC circuit 11. The two ends formed by the series connection of the first bus capacitor Cbus1 and the second bus capacitor Cbus2 correspond to the DC terminals DC21 and DC22 of the AC / DC circuit, respectively. The DC / AC circuit is... Figure 5b The circuit structure shown consists of a third inductor Lout2 connected between the midpoint a3 of the third phase bridge arm 113 and the second output terminal out12 of the AC / AC circuit 11, a fourth inductor Lout3 connected between the midpoint a4 of the fourth phase bridge arm 114 and the third output terminal out13 of the AC / AC circuit 11, and the third phase bridge arm 113 and the fourth phase bridge arm 114 connected in parallel. The two ends formed by the parallel connection of the third phase bridge arm 113 and the fourth phase bridge arm 114 correspond to the DC input terminals inDC21 and inDC22 of the DC / AC circuit, respectively.

[0173] When the power conversion device 1 has a three-phase input and three-phase output circuit structure and the AC / AC circuit 11 is Figure 7b When the AC / AC circuit 11 is shown, the AC / DC circuit is... Figure 7b The circuit structure shown consists of the branch containing the two bus capacitors connected in series, the first phase bridge arm 111, the second phase bridge arm 112, the third phase bridge arm 113, and the fourth phase bridge arm 114 connected in parallel, the first inductor Lin1 connected between the midpoint a1 of the first phase bridge arm 111 and the first input terminal in11 of the AC / AC circuit 11, the second inductor Lin2 connected between the midpoint a2 of the second phase bridge arm 112 and the second input terminal in12 of the AC / AC circuit 11, the third inductor Lin3 connected between the midpoint a3 of the third phase bridge arm 113 and the third input terminal in13 of the AC / AC circuit 11, and the fourth inductor Lout1 connected between the midpoint a4 of the fourth phase bridge arm 114 and the first output terminal out11 of the AC / AC circuit 11. The two ends formed by the series connection of the first bus capacitor Cbus1 and the second bus capacitor Cbus2 correspond to the DC terminals DC21 and DC22 of the AC / DC circuit, respectively. The DC / AC circuit is... Figure 7bThe circuit structure shown consists of the fourth inductor Lout1 connected between the midpoint a4 of the fourth phase bridge arm 114 and the first output terminal out11 of the AC / AC circuit 11; the fifth inductor Lout2 connected between the midpoint a5 of the fifth phase bridge arm 115 and the second output terminal out12 of the AC / AC circuit 11; the sixth inductor Lout3 connected between the midpoint a6 of the sixth phase bridge arm 116 and the third output terminal out13 of the AC / AC circuit 11; and the fourth phase bridge arm 114, the fifth phase bridge arm 115, and the sixth phase bridge arm 116 connected in parallel. The two ends formed by the parallel connection of the fourth phase bridge arm 114, the fifth phase bridge arm 115, and the sixth phase bridge arm 116 correspond to the DC input terminals inDC21 and inDC22 of the DC / AC circuit, respectively.

[0174] After the power conversion device 1 is working, it can convert the energy input from the AC grid and the photovoltaic string and output it to the AC load. Specifically, the energy input from the AC grid flows into the AC load after passing through the first filter inductor L1, the AC / DC circuit, the DC / AC circuit and the first filter inductor L1 in sequence. In addition, the DC power input from the photovoltaic string passes through the DC / DC circuit 12 and the DC / AC circuit in sequence to obtain the inverted AC power. This AC power flows into the AC load after passing through the first filter inductor L1 to realize the power supply to the AC load.

[0175] Optionally, the power conversion device 1 further includes a second DC input terminal for connecting to the energy storage unit. This second DC input terminal is connected to the DC terminal of the AC / DC circuit. When the second DC input terminal of the power conversion device 1 is connected to the energy storage unit, the energy flow direction between the AC input terminal and the second DC input terminal of the power conversion device 1 can be bidirectional. Specifically, when the AC grid provides energy to the energy storage unit, the AC energy output from the AC grid flows through the first filter inductor L1, is rectified by the AC / DC circuit, and then flows into the energy storage unit to supply power to the energy storage unit. When the energy storage unit provides energy to the AC grid, the DC power output from the energy storage unit is inverted by the AC / DC circuit, flows through the first filter inductor L1, and then flows into the AC grid to supply power to the AC grid.

[0176] Here, for the derivation process of the current flow direction of power conversion device 1 and the beneficial effects brought about by the circuit structure of power conversion device 1, please refer to [link to relevant documentation]. Figure 3a The description of the corresponding part in the power conversion device 1 shown is not repeated here.

[0177] In this embodiment, the first filter inductor L1 not only performs the functions of the input filter inductor Lin and the output filter inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art, but also, compared to the input filter inductor Lin and the output filter inductor Lout of a single-phase input, single-phase output AC / AC power supply in the prior art, the first filter inductor L1 reduces one inductor winding and one inductor core, thereby reducing the size of the power conversion device 1 and lowering the circuit cost of the power conversion device 1. Furthermore, when the power conversion device 1 provided in this application is an inverter, it can also be applied to photovoltaic power supply scenarios, demonstrating strong applicability.

[0178] also, Figures 3b to 7d The specific circuit structure of the filter inductor, filter capacitor, and AC / AC circuit 11 in the power conversion device 1 shown, the energy flow of the power conversion device 1, and the beneficial effects brought about by the circuit structure of the power conversion device 1 are also applicable to the inverter, and will not be elaborated here.

[0179] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A power conversion device, characterized in that, The power conversion device includes an AC input terminal, an AC output terminal, a first filter inductor, a first filter capacitor, a second filter capacitor, a third filter capacitor, and an AC / AC circuit. The first filter inductor includes a first inductor winding, a second inductor winding, a third inductor winding, and a first inductor core. The AC input terminal of the power conversion device includes a first input terminal and a second input terminal. The AC output terminal of the power conversion device includes a first output terminal and a second output terminal, wherein: The first inductor winding, the second inductor winding, and the third inductor winding are all wound on the first inductor core; The first end of the first inductor winding is connected to the first input terminal of the power conversion device, the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device, and the second ends of the first inductor winding and the second inductor winding are respectively connected to the input terminal of the AC / AC circuit. The first end of the third inductor winding is connected to the first output terminal of the power conversion device, and the second end of the second inductor winding and the second end of the third inductor winding are respectively connected to the output terminal of the AC / AC circuit. The first filter capacitor is connected between the first input terminal and the first output terminal of the power conversion device, or between the second input terminal and the second output terminal of the power conversion device; The second filter capacitor is connected between the second end of the first inductor winding and the second end of the third inductor winding, and the third filter capacitor is connected between the second output terminal of the power conversion device and the ground wire.

2. The power conversion device according to claim 1, characterized in that, The power conversion device further includes a second filter inductor, which comprises a fourth inductor winding, a fifth inductor winding, a sixth inductor winding, and a second inductor core, wherein: The fourth inductor winding, the fifth inductor winding, and the sixth inductor winding are all wound on the second inductor core; The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the fourth inductor winding; the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device through the fifth inductor winding; and the first end of the third inductor winding is connected to the first output terminal of the power conversion device through the sixth inductor winding.

3. The power conversion device according to claim 1, characterized in that, The power conversion device further includes a second filter inductor, which comprises a fourth inductor winding, a fifth inductor winding, a sixth inductor winding, a seventh inductor winding, and a second inductor core, wherein: The fourth inductor winding, the fifth inductor winding, the sixth inductor winding, and the seventh inductor winding are all wound on the second inductor core; The first end of the first inductor winding is connected to the first input end of the power conversion device through the fourth inductor winding; The first end of the second inductor winding is connected to the second input terminal of the power conversion device through the fifth inductor winding, and the first end of the second inductor winding is connected to the second output terminal of the power conversion device through the sixth inductor winding; The first end of the third inductor winding is connected to the first output end of the power conversion device through the seventh inductor winding.

4. The power conversion device according to any one of claims 1-3, characterized in that, The input terminals of the AC / AC circuit include a first input terminal and a common terminal, and the output terminals of the AC / AC circuit include a first output terminal and the common terminal, wherein: The second end of the first inductor winding is connected to the first input terminal of the AC / AC circuit, the second end of the second inductor winding is connected to the common terminal of the AC / AC circuit, and the second end of the third inductor winding is connected to the first output terminal of the AC / AC circuit.

5. The power conversion device according to claim 1, characterized in that, The first filter inductor further includes a fourth inductor winding and a fifth inductor winding, and the AC output terminal of the power conversion device further includes a third output terminal and a fourth output terminal, wherein: The fourth inductor winding and the fifth inductor winding are both wound on the first inductor core; The first end of the fourth inductor winding is connected to the third output terminal of the power conversion device, the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device, and the second ends of the fourth inductor winding and the fifth inductor winding are respectively connected to the output terminal of the AC / AC circuit.

6. The power conversion device according to claim 5, characterized in that, The power conversion device further includes a second filter inductor, which comprises a sixth inductor winding, a seventh inductor winding, an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, and a second inductor core, wherein: The sixth, seventh, eighth, ninth, and tenth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the sixth inductor winding; the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device through the seventh inductor winding; and the first end of the third inductor winding is connected to the first output terminal of the power conversion device through the eighth inductor winding. The first end of the fourth inductor winding is connected to the third output terminal of the power conversion device through the ninth inductor winding, and the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device through the tenth inductor winding.

7. The power conversion device according to claim 5, characterized in that, The power conversion device further includes a second filter inductor, which comprises a sixth inductor winding, a seventh inductor winding, an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, an eleventh inductor winding, and a second inductor core, wherein: The sixth, seventh, eighth, ninth, tenth, and eleventh inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the sixth inductor winding; the first end of the second inductor winding is connected to the second input terminal of the power conversion device through the seventh inductor winding; and the first end of the second inductor winding is connected to the second output terminal of the power conversion device through the eighth inductor winding. The first end of the third inductor winding is connected to the first output terminal of the power conversion device through the ninth inductor winding, the first end of the fourth inductor winding is connected to the third output terminal of the power conversion device through the tenth inductor winding, and the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device through the eleventh inductor winding.

8. The power conversion device according to any one of claims 5-7, characterized in that, The input terminals of the AC / AC circuit include a first input terminal and a common terminal, and the output terminals of the AC / AC circuit include a first output terminal, a second output terminal, a third output terminal, and the common terminal, wherein: The second end of the first inductor winding is connected to the first input terminal of the AC / AC circuit, and the second end of the second inductor winding is connected to the common terminal of the AC / AC circuit. The second end of the third inductor winding is connected to the first output terminal of the AC / AC circuit, the second end of the fourth inductor winding is connected to the second output terminal of the AC / AC circuit, and the second end of the fifth inductor winding is connected to the third output terminal of the AC / AC circuit.

9. The power conversion device according to claim 1, characterized in that, The first filter inductor further includes a fourth inductor winding and a fifth inductor winding, and the AC input terminal of the power conversion device further includes a third input terminal and a fourth input terminal, wherein: The fourth inductor winding and the fifth inductor winding are both wound on the first inductor core; The first end of the fourth inductor winding is connected to the third input terminal of the power conversion device, the first end of the fifth inductor winding is connected to the fourth input terminal of the power conversion device, and the second ends of the fourth inductor winding and the fifth inductor winding are respectively connected to the input terminal of the AC / AC circuit.

10. The power conversion device according to claim 9, characterized in that, The power conversion device further includes a second filter inductor, which comprises a sixth inductor winding, a seventh inductor winding, an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, and a second inductor core, wherein: The sixth, seventh, eighth, ninth, and tenth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the sixth inductor winding; the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device through the seventh inductor winding; and the first end of the third inductor winding is connected to the first output terminal of the power conversion device through the eighth inductor winding. The first end of the fourth inductor winding is connected to the third input terminal of the power conversion device through the ninth inductor winding, and the first end of the fifth inductor winding is connected to the fourth input terminal of the power conversion device through the tenth inductor winding.

11. The power conversion device according to claim 9, characterized in that, The power conversion device further includes a second filter inductor, which comprises a sixth inductor winding, a seventh inductor winding, an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, an eleventh inductor winding, and a second inductor core, wherein: The sixth, seventh, eighth, ninth, and tenth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the sixth inductor winding; the first end of the second inductor winding is connected to the second input terminal of the power conversion device through the seventh inductor winding; the first end of the second inductor winding is connected to the second output terminal of the power conversion device through the eighth inductor winding; and the first end of the third inductor winding is connected to the first output terminal of the power conversion device through the ninth inductor winding. The first end of the fourth inductor winding is connected to the third input terminal of the power conversion device through the tenth inductor winding, and the first end of the fifth inductor winding is connected to the fourth input terminal of the power conversion device through the eleventh inductor winding.

12. The power conversion device according to any one of claims 9-11, characterized in that, The input terminals of the AC / AC circuit include a first input terminal, a second input terminal, a third input terminal, and a common terminal. The output terminals of the AC / AC circuit include a first output terminal and the common terminal, wherein: The second end of the first inductor winding is connected to the first input terminal of the AC / AC circuit, the second end of the fourth inductor winding is connected to the second input terminal of the AC / AC circuit, and the second end of the fifth inductor winding is connected to the third input terminal of the AC / AC circuit. The second end of the second inductor winding is connected to the common terminal of the AC / AC circuit, and the second end of the third inductor winding is connected to the first output terminal of the AC / AC circuit.

13. The power conversion device according to any one of claims 1-3, 5-7, and 9-11, characterized in that, The power conversion device is an uninterruptible power supply.

14. The power conversion device according to any one of claims 1-3, 5-7, and 9-11, characterized in that, The power conversion device is an inverter. The input terminal of the AC / AC circuit is a bidirectional input / output terminal of the AC / AC circuit. The inverter also includes a first DC input terminal and a DC / DC circuit. The AC / AC circuit includes an AC / DC circuit and a DC / AC circuit, wherein: The first DC input terminal of the inverter is used to connect to the photovoltaic string; The AC terminal of the AC / DC circuit serves as the bidirectional input and output terminal of the AC / DC circuit, and the DC terminal of the AC / DC circuit is connected to the DC input terminal of the DC / AC circuit and the DC output terminal of the DC / DC circuit. The AC output terminal of the DC / AC circuit serves as the output terminal of the AC / AC circuit, and the DC input terminal of the DC / DC circuit is connected to the first DC input terminal of the inverter.

15. A power conversion device, characterized in that, The power conversion device includes an AC input terminal, an AC output terminal, a first filter inductor, a first filter capacitor, a second filter capacitor, a third filter capacitor, and an AC / AC circuit. The first filter inductor includes a first inductor winding, a second inductor winding, a third inductor winding, a fourth inductor winding, a fifth inductor winding, a sixth inductor winding, a seventh inductor winding, and a first inductor core. The AC input terminal of the power conversion device includes a first input terminal, a second input terminal, a third input terminal, and a fourth input terminal. The AC output terminal of the power conversion device includes a first output terminal, a second output terminal, a third output terminal, and a fourth output terminal, wherein: The first inductor winding, the second inductor winding, the third inductor winding, the fourth inductor winding, the fifth inductor winding, the sixth inductor winding, and the seventh inductor winding are all wound on the first inductor core; The first end of the first inductor winding is connected to the first input terminal of the power conversion device, the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device, and the second ends of the first inductor winding and the second inductor winding are respectively connected to the input terminal of the AC / AC circuit. The first end of the third inductor winding is connected to the first output terminal of the power conversion device, and the second end of the second inductor winding and the second end of the third inductor winding are respectively connected to the output terminal of the AC / AC circuit. The first end of the fourth inductor winding is connected to the third output terminal of the power conversion device, the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device, and the second ends of the fourth inductor winding and the second ends of the fifth inductor winding are respectively connected to the output terminal of the AC / AC circuit. The first end of the sixth inductor winding is connected to the third input terminal of the power conversion device, the first end of the seventh inductor winding is connected to the fourth input terminal of the power conversion device, and the second ends of the sixth inductor winding and the second ends of the seventh inductor winding are respectively connected to the input terminal of the AC / AC circuit. The first filter capacitor is connected between the first input terminal and the first output terminal of the power conversion device, or between the third input terminal and the third output terminal of the power conversion device, or between the fourth input terminal and the fourth output terminal of the power conversion device, or between the second input terminal and the second output terminal of the power conversion device; The second filter capacitor is connected between the second end of the first inductor winding and the second end of the third inductor winding, or between the second end of the sixth inductor winding and the second end of the fourth inductor winding, or between the second end of the seventh inductor winding and the second end of the fifth inductor winding; The third filter capacitor is connected between the second output terminal of the power conversion device and the ground wire.

16. The power conversion device according to claim 15, characterized in that, The power conversion device further includes a second filter inductor, which comprises an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, an eleventh inductor winding, a twelfth inductor winding, a thirteenth inductor winding, a fourteenth inductor winding, and a second inductor core, wherein: The eighth, ninth, tenth, eleventh, twelfth, thirteenth, and fourteenth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the eighth inductor winding; the first end of the second inductor winding is connected to the second input terminal and the second output terminal of the power conversion device through the ninth inductor winding; and the first end of the third inductor winding is connected to the first output terminal of the power conversion device through the tenth inductor winding. The first end of the fourth inductor winding is connected to the third output terminal of the power conversion device through the eleventh inductor winding, and the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device through the twelfth inductor winding. The first end of the sixth inductor winding is connected to the third input terminal of the power conversion device through the thirteenth inductor winding, and the first end of the seventh inductor winding is connected to the fourth input terminal of the power conversion device through the fourteenth inductor winding.

17. The power conversion device according to claim 15, characterized in that, The power conversion device further includes a second filter inductor, which comprises an eighth inductor winding, a ninth inductor winding, a tenth inductor winding, an eleventh inductor winding, a twelfth inductor winding, a thirteenth inductor winding, a fourteenth inductor winding, a fifteenth inductor winding, and a second inductor core, wherein: The eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, and fifteenth inductor windings are all wound on the second inductor core. The first end of the first inductor winding is connected to the first input terminal of the power conversion device through the eighth inductor winding; the first end of the second inductor winding is connected to the second input terminal of the power conversion device through the ninth inductor winding; and the first end of the second inductor winding is connected to the second output terminal of the power conversion device through the tenth inductor winding. The first end of the third inductor winding is connected to the first output terminal of the power conversion device through the eleventh inductor winding; the first end of the fourth inductor winding is connected to the third output terminal of the power conversion device through the twelfth inductor winding; and the first end of the fifth inductor winding is connected to the fourth output terminal of the power conversion device through the thirteenth inductor winding. The first end of the sixth inductor winding is connected to the third input terminal of the power conversion device through the fourteenth inductor winding, and the first end of the seventh inductor winding is connected to the fourth input terminal of the power conversion device through the fifteenth inductor winding.

18. The power conversion device according to any one of claims 15-17, characterized in that, The input terminals of the AC / AC circuit include a first input terminal, a second input terminal, a third input terminal, and a common terminal. The output terminals of the AC / AC circuit include a first output terminal, a second output terminal, a third output terminal, and the common terminal, wherein: The second end of the first inductor winding is connected to the first input terminal of the AC / AC circuit, the second end of the sixth inductor winding is connected to the second input terminal of the AC / AC circuit, the second end of the seventh inductor winding is connected to the third input terminal of the AC / AC circuit, and the second end of the second inductor winding is connected to the common terminal of the AC / AC circuit. The second end of the third inductor winding is connected to the first output terminal of the AC / AC circuit, the second end of the fourth inductor winding is connected to the second output terminal of the AC / AC circuit, and the second end of the fifth inductor winding is connected to the third output terminal of the AC / AC circuit.

19. The power conversion device according to any one of claims 15-17, characterized in that, The power conversion device is an uninterruptible power supply.

20. The power conversion device according to any one of claims 15-17, characterized in that, The power conversion device is an inverter. The input terminal of the AC / AC circuit is a bidirectional input / output terminal of the AC / AC circuit. The inverter also includes a first DC input terminal and a DC / DC circuit. The AC / AC circuit includes an AC / DC circuit and a DC / AC circuit, wherein: The first DC input terminal of the inverter is used to connect to the photovoltaic string; The AC terminal of the AC / DC circuit serves as the bidirectional input and output terminal of the AC / DC circuit, and the DC terminal of the AC / DC circuit is connected to the DC input terminal of the DC / AC circuit and the DC output terminal of the DC / DC circuit. The AC output terminal of the DC / AC circuit serves as the output terminal of the AC / AC circuit, and the DC input terminal of the DC / DC circuit is connected to the first DC input terminal of the inverter.

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