CN114337333A

CN114337333A - Conversion circuit, converter and electronic equipment

Info

Publication number: CN114337333A
Application number: CN202011380821.4A
Authority: CN
Inventors: 张贺军; 闫超; 孟元东; 邹丽霞
Original assignee: Huawei Digital Power Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2022-04-12

Abstract

The application provides a converting circuit, converter and electronic equipment, and the converting circuit includes first electric capacity and second electric capacity, and first electric capacity and second electric capacity are established ties between the high potential end and the low potential end of the direct current port of converting circuit, and the zero line interface connection of converting circuit is between first electric capacity and second electric capacity. The voltage difference of the direct current port of the conversion circuit is small when the conversion circuit processes single-phase electricity and three-phase electricity, and the hardware type selection of the conversion circuit is facilitated according to the voltage standard of the uniform direct current port, so that the obtained conversion circuit has good performance when the conversion circuit processes the single-phase electricity and the three-phase electricity.

Description

Conversion circuit, converter and electronic equipment

Technical Field

The application relates to the technical field of new energy vehicles, in particular to a conversion circuit, a converter and electronic equipment.

Background

An ac-dc converter is a common electronic device, and the ac-dc converter can convert received ac power into dc power, and is therefore commonly used in new energy vehicles, household appliances and other electronic devices powered by ac power.

At present, the common alternating current in the commercial power mainly comprises single-phase electricity and three-phase electricity. Generally, in China, single-phase electricity can be transmitted through a zero line and a live line. The single-phase power fluctuates in a periodic sine wave manner between +/-311V, the peak value of the voltage is 311V, and the effective value of the voltage is 220V. The three-phase electricity can be transmitted through the phase line A, the phase line B and the phase line C, and each phase line can independently transmit single-phase electricity. That is, the three-phase electricity includes three single-phase electricity of the same frequency and amplitude, which is generally represented by a-phase electricity, B-phase electricity, and C-phase electricity. Wherein, the phase difference among the phase A electricity, the phase B electricity and the phase C electricity is 120 degrees respectively. For example, at some point in time phase a is 0 °, phase B is 120 °, and phase C is 240 ° (-120 °). Generally, in the commercial power in China, each phase of three-phase power fluctuates periodically in a sine wave manner within +/-311V, the peak value of a phase voltage is 311V, and the effective value of the phase voltage is 220V. In three-phase power, the voltage between any two phases of power is called line voltage, and in Chinese commercial power, the peak value of the line voltage is 539V, and the effective value of the line voltage is 381V.

Because the single-phase electricity and the three-phase electricity are common alternating currents in the commercial power, the alternating current-direct current converter which can realize the compatibility of the single-phase electricity and the three-phase electricity has wide application prospect. However, when the current ac-dc converter processes single-phase electricity and three-phase electricity, the difference of the output dc voltage is large, so that the performance of the ac-dc converter after the single-phase electricity and the three-phase electricity are compatible is not ideal.

Disclosure of Invention

In view of the above, the present application provides a conversion circuit, a converter and an electronic device, which are used for realizing single-phase and three-phase compatible ac-dc conversion and dc-ac conversion.

In a first aspect, an embodiment of the present application provides a conversion circuit, which mainly includes: the bridge type switching circuit comprises a first interface, a second interface, a third interface, a zero line interface, a first bidirectional switch, a bridge type switching circuit, a first capacitor and a second capacitor, wherein the bridge type switching circuit comprises three bridge arms. When single-phase electricity is processed, the first interface can be connected with a live wire, and when three-phase electricity is processed, the first interface can be connected with a first phase wire. The first phase line may be any one of three phase lines for transmitting three-phase power. The second interface can be connected with a second phase line, and the second phase line can be any one of three phase lines for transmitting three-phase electricity except the first phase line. The third interface may be connected to a third phase line, and the third phase line may be a phase line other than the first phase line and the second phase line among three phase lines transmitting three-phase power. The neutral wire interface may be connected to a neutral wire.

The first interface is connected with a first bridge arm of the bridge type conversion circuit, the first end of the first bidirectional switch is connected with a second bridge arm of the bridge type conversion circuit, the second end of the first bidirectional switch is connected with the first interface, and the third end of the first bidirectional switch is connected with the second interface. The first bidirectional switch can conduct the connection between the second bridge arm and the first interface when processing single-phase power, and conduct the connection between the second bridge arm and the second interface when processing three-phase power.

The bridge conversion circuit may convert single-phase or three-phase electricity into direct current and output the direct current from a direct current port of the conversion circuit, or receive the direct current through the direct current port and convert the direct current into single-phase or three-phase electricity. One end of the first capacitor is connected with the high potential end of the direct current port, the other end of the first capacitor is connected with one end of the second capacitor, the other end of the second capacitor is connected with the low potential end of the direct current port, and the zero line interface is connected between the first capacitor and the second capacitor.

By adopting the conversion circuit provided by the embodiment of the application, when three-phase electricity is processed, the minimum voltage of the direct current port can be the peak value of line voltage. For three-phase power in Chinese commercial power, considering the influence of power grid fluctuation factors, the peak value of the line voltage can be assumed to be 649V. Since the converter circuit has a boosting function, the switching tube and the inductor in the converter circuit are generally required to be selected according to the minimum voltage of 800V at the dc port.

When processing single-phase electricity, the minimum voltage of the dc port may be the peak voltage of the single-phase electricity. For single-phase electricity in the commercial power in china, the peak value of the single-phase voltage can be assumed to be 265V in consideration of the influence of the power grid fluctuation factor. In the embodiment of the application, the first capacitor and the second capacitor are connected in series between the high potential end and the low potential end of the direct current port, and the zero line interface is connected between the first capacitor and the second capacitor, so that the voltage of the other end of the first capacitor connected with the zero line interface and the voltage of the one end of the second capacitor connected with the zero line interface are 0V. When single-phase electricity is converted, the voltage of the first capacitor can reach the peak value 265V of the single-phase electricity voltage, the voltage of the second capacitor can also reach the peak value 265V of the single-phase electricity voltage, and therefore the voltage of the direct current port can reach 730V. That is to say, for single-phase power in the commercial power in china, the embodiment of the present application may select the switching tube and the inductor in the conversion circuit according to the minimum voltage of the dc port of 730V.

Therefore, when the conversion circuit provided by the embodiment of the application processes single-phase electricity and three-phase electricity, the hardware design standards are relatively close, so that the hardware of the conversion circuit is favorably selected by adopting a unified design standard, and the conversion circuit obtained according to the design standard can have better performance when processing single-phase electricity and three-phase electricity.

Generally, the conversion circuit also has a boosting function. Illustratively, the conversion circuit may further include a first inductor, a second inductor, and a third inductor. The first inductor is connected between the first interface and the first bridge arm, the second inductor is connected between the first end of the first bidirectional switch and the second bridge arm, and the third inductor is connected between the third interface and the third bridge arm.

The first inductor, the second inductor and the third inductor can enable the conversion circuit to have a boosting function. Meanwhile, the first inductor, the second inductor and the third inductor can also prevent the first interface, the second interface, the third interface and the PN interface of the conversion circuit from being short-circuited with the direct-current port, so that the conversion circuit is protected. The first inductor, the second inductor and the third inductor can also filter the current in the conversion circuit, so that the loss of the conversion circuit is reduced.

In order to protect the first capacitor and the second capacitor, in a possible implementation manner, the conversion circuit further includes a second bidirectional switch, a first end of the second bidirectional switch is connected to one end of the third inductor, which is far away from the third bridge arm, a second end of the second bidirectional switch is connected to the third interface, and a third end of the second bidirectional switch is connected to the neutral line interface. The second bidirectional switch can conduct connection between the third inductor and the zero line interface when single-phase power is processed, and conduct connection between the third interface and the zero line interface when three-phase power is processed.

In particular, the second bidirectional switch conducts the connection between the third inductance and the neutral interface when processing single-phase power. In this case, the voltages of the first capacitor and the second capacitor can be adjusted through the third bridge arm and the third inductor, so that the voltage of any one of the first capacitor and the second capacitor is prevented from being too large, and the safety of the first capacitor and the second capacitor can be protected.

In order to protect the first capacitor and the second capacitor, in another possible implementation manner, the switching circuit may further include a third bidirectional switch, a first end of the third bidirectional switch is connected to one end of the third inductor, which is far away from the third bridge arm, a second end of the third bidirectional switch is connected to the first end of the first bidirectional switch, and a third end of the third bidirectional switch is connected to the third interface. The third bidirectional switch may conduct a connection between the first terminal of the first bidirectional switch and the third inductor when processing single-phase power, and conduct a connection between the third interface and the third inductor when processing three-phase power. By adopting the implementation mode, when single-phase electricity is processed, the first inductor, the second inductor and the third inductor can transmit the single-phase electricity in parallel, so that the single-phase electricity processing device can be suitable for the high-power single-phase electricity condition.

In this case, the bridge conversion circuit may further include a fourth bridge arm, the conversion circuit may further include a fourth inductor, one end of the fourth inductor is connected to the fourth bridge arm, and the other end of the fourth inductor is connected between the first capacitor and the second capacitor. The voltages of the first capacitor and the second capacitor can be adjusted through the fourth bridge arm and the fourth bridge arm, so that the voltage of any one of the first capacitor and the second capacitor is prevented from being overlarge, and the safety of the first capacitor and the second capacitor can be protected.

In order to enlarge the adjustable range of the voltage of the direct current port when the conversion circuit processes three-phase electricity, the conversion circuit further comprises a third switch, the third switch is connected between the zero line interface and the first capacitor, and the third switch is used for being switched on when single-phase electricity is processed and being switched off when the three-phase electricity is processed.

Specifically, when the single-phase power is processed, the third switch is turned on, and the conversion circuit can be connected to the zero line to form a circuit. If the third switch remains on while processing the three-phase power, the minimum value of the voltage at the dc port becomes twice the peak value of the phase voltage, for example, 730V. And after the third switch is turned off, the minimum value of the voltage of the direct current port is the peak value of the line voltage, such as 649V. Therefore, when the third switch is turned off during processing of three-phase power, the minimum value of the voltage of the direct current port can be reduced, and the range of the voltage of the direct current port can be expanded.

In order to protect the conversion circuit, in one possible implementation, the conversion circuit further includes a fourth switch, a fifth switch, and a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode. One end of the fourth switch is connected with the cathode of the first diode, the cathode of the second diode and the cathode of the third diode respectively, and the other end of the fourth switch is connected with the high-potential end of the direct-current port. The anode of the first diode is connected with the cathode of the fourth diode, the anode of the second diode is connected with the cathode of the fifth diode, and the anode of the third diode is connected with the cathode of the sixth diode. One end of the fifth switch is connected with the anode of the fourth diode, the anode of the fifth diode and the anode of the sixth diode respectively, and the other end of the fourth switch is connected with the low-potential end of the direct-current port. The fourth switch and the fifth switch can be switched on when single-phase power or three-phase power is converted into direct current, and can be switched off when the direct current is converted into the single-phase power or the three-phase power.

By adopting the implementation mode, the fourth switch and the fifth switch are switched on when the single-phase power or the three-phase power is converted into the direct current, and the overlarge voltage can be released through the diode when the effective value of the voltage of the single-phase power or the three-phase power is suddenly changed (suddenly increased), so that the overlarge voltage can be prevented from passing through the bridge type conversion circuit, and the safety of the conversion circuit is protected. When the direct current is converted into single-phase power or three-phase power, the fourth switch and the fifth switch are disconnected, so that the first diode to the sixth diode are suspended, and the direct current-alternating current conversion process cannot be influenced.

The bridge conversion circuit in the embodiment of the application can be a rectifying circuit or an inverter circuit. Illustratively, the first bridge arm comprises a first switching tube and a second switching tube which are connected in series, the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series, and the third bridge arm comprises a fifth switching tube and a sixth switching tube which are connected in series. The first electrode of the first switching tube, the first electrode of the third switching tube and the first electrode of the fifth switching tube are connected with the high-potential end of the direct-current port. The second electrode of the first switching tube is connected with the first electrode of the second switching tube, the second electrode of the third switching tube is connected with the first electrode of the fourth switching tube, and the second electrode of the fifth switching tube is connected with the first electrode of the sixth switching tube. And the second electrode of the fourth switching tube, the second electrode of the fifth switching tube and the second electrode of the sixth switching tube are connected with the low-potential end of the direct-current port.

In a second aspect, embodiments of the present application provide a converter, which mainly includes a conversion circuit and a controller. The conversion circuit may be the conversion circuit provided in any one of the first aspect, and the technical effects of the corresponding solutions in the second aspect may refer to the technical effects that can be obtained by the corresponding solutions in the first aspect, and repeated parts are not described in detail.

Illustratively, the conversion circuit includes a first interface, a second interface, a third interface, a neutral line interface, a first bidirectional switch, a bridge conversion circuit, a first capacitor, and a second capacitor, and the bridge conversion circuit includes three bridge arms. The first interface is connected with a first bridge arm of the bridge type conversion circuit, and the first interface can be connected with a live wire or a first phase wire. The first end of the first bidirectional switch is connected with the second bridge arm of the bridge type conversion circuit, the second end of the first bidirectional switch is connected with the first interface, the third end of the first bidirectional switch is connected with the second interface, and the second interface can be connected with the second phase line; and the third interface is connected with a third bridge arm of the conversion circuit and is used for connecting a third phase line. One end of the first capacitor is connected with the high potential end of the direct current port, the other end of the first capacitor is connected with one end of the second capacitor, the other end of the second capacitor is connected with the low potential end of the direct current port, the zero line interface is connected between the first capacitor and the second capacitor, and the zero line interface can be connected with a zero line.

In this case, the controller may control the first bidirectional switch to turn on the connection between the second bridge arm and the first interface when processing single-phase power; when three-phase electricity is processed, the first bidirectional switch is controlled to conduct connection between the second bridge arm and the second interface; and the controller can also control the bridge type conversion circuit to convert the single-phase power or the three-phase power into direct current and output the direct current from the direct current port of the conversion circuit, or receive the direct current through the direct current port and convert the direct current into the single-phase power or the three-phase power.

The conversion circuit generally has a boosting function, and specifically, the conversion circuit may further include a first inductor, a second inductor, and a third inductor; the first inductor is connected between the first interface and the first bridge arm, the second inductor is connected between the first bidirectional switch and the second bridge arm, and the third inductor is connected between the third interface and the third bridge arm.

In order to protect the first capacitor and the second capacitor, in a possible implementation manner, the conversion circuit may further include a second bidirectional switch, a first end of the second bidirectional switch is connected to one end of the third inductor, which is far away from the third bridge arm, a second end of the second bidirectional switch is connected to the third interface, and a third end of the second bidirectional switch is connected to the neutral line interface.

In this case, the controller may further control the second bidirectional switch to conduct the connection between the third inductor and the zero line interface when processing the single-phase power; and when the three-phase power is processed, the second bidirectional switch is controlled to conduct the connection between the third interface and the zero line interface. After the second bidirectional switch is controlled to conduct the connection between the third inductor and the zero line interface, the controller can adjust the voltage of the first capacitor and the second capacitor through the third inductor and the third bridge arm, and the voltage of any one of the first capacitor and the second capacitor is prevented from being too large, so that the safety of the first capacitor and the second capacitor can be protected.

Specifically, the converter provided by the embodiment of the present application may further include a detection circuit, and the detection circuit may detect the voltage of the first capacitor and the voltage of the second capacitor. The controller may obtain the voltage of the first capacitor and the voltage of the second capacitor through the detection circuit. And when the voltage of the first capacitor is greater than that of the second capacitor, controlling the third bridge arm to reduce the voltage of the first capacitor and increase the voltage of the second capacitor. When the voltage of the first capacitor is smaller than the voltage of the second capacitor, the controller can also control the third bridge arm to increase the voltage of the first capacitor and decrease the voltage of the second capacitor.

Illustratively, the third bridge arm includes a fifth switching tube and a sixth switching tube, a first electrode of the fifth switching tube is connected to the high-potential end of the dc port, a second electrode of the fifth switching tube is connected to the third inductor and the first electrode of the sixth switching tube, respectively, and a second electrode of the sixth switching tube is connected to the low-potential end of the dc port;

in this case, when the voltage of the first capacitor is greater than the voltage of the second capacitor, the controller may turn on the fifth switching tube and turn off the sixth switching tube, so that the third inductor is charged and the voltage of the first capacitor is reduced. And then the controller disconnects the fifth switching tube and conducts the sixth switching tube so as to discharge the third inductor and increase the voltage of the second capacitor. The controller may repeatedly turn on and off the fifth switching tube and the sixth switching tube for one or more cycles to gradually approach the voltage of the first capacitor to the voltage of the second capacitor until the voltage of the first capacitor is equal to the voltage of the second capacitor.

When the voltage of the first capacitor is less than the voltage of the second capacitor, the controller may turn on the sixth switching tube and turn off the fifth switching tube, so that the third inductor is charged and the voltage of the second capacitor is reduced. And then the controller disconnects the sixth switching tube and switches on the fifth switching tube so as to discharge the third inductor and increase the voltage of the first capacitor. The controller may repeatedly turn on and off the fifth switching tube and the sixth switching tube for one or more cycles to gradually approach the voltage of the first capacitor to the voltage of the second capacitor until the voltage of the first capacitor is equal to the voltage of the second capacitor.

In order to protect the first capacitor and the second capacitor, in another possible implementation manner, the conversion circuit may further include a third bidirectional switch, a first end of the third bidirectional switch is connected to one end of the third inductor, which is far away from the third bridge arm, a second end of the third bidirectional switch is connected to the first end of the first bidirectional switch, and a third end of the third bidirectional switch is connected to the third interface.

The controller may turn on the connection between the first terminal of the first bidirectional switch and the third inductor when processing the single-phase power; the connection between the third interface and the third inductance is switched on when processing the three-phase power.

In this case, the bridge conversion circuit further includes a fourth bridge arm, the conversion circuit further includes a fourth inductor, one end of the fourth inductor is connected to the fourth bridge arm, and the other end of the fourth inductor is connected between the first capacitor and the second capacitor. The converter may further include a detection circuit that may detect a voltage of the first capacitor, and a voltage of the second capacitor. The controller can also acquire the voltage of the first capacitor and the voltage of the second capacitor through the detection circuit. When the voltage of the first capacitor is larger than that of the second capacitor, controlling the fourth bridge arm and the fourth inductor to reduce the voltage of the first capacitor and increase the voltage of the second capacitor; and when the voltage of the first capacitor is smaller than that of the second capacitor, controlling the fourth bridge arm and the fourth inductor to increase the voltage of the first capacitor and reduce the voltage of the second capacitor.

For example, the fourth bridge arm may include a seventh switching tube and an eighth switching tube, a first electrode of the seventh switching tube is connected to the high potential end of the dc port, a second electrode of the seventh switching tube is connected to the fourth inductor and the first electrode of the eighth switching tube, respectively, and a second electrode of the eighth switching tube is connected to the low potential end of the dc port.

When the voltage of the first capacitor is greater than the voltage of the second capacitor, the controller may turn on the seventh switching tube and turn off the eighth switching tube, so that the fourth inductor is charged and the voltage of the first capacitor is reduced. And then the controller turns off the seventh switch tube and turns on the eighth switch tube to discharge the fourth inductor and increase the voltage of the second capacitor.

When the voltage of the first capacitor is lower than the voltage of the second capacitor, the controller may turn on the eighth switching tube and turn off the seventh switching tube, so that the fourth inductor is charged and the voltage of the second capacitor is reduced. And then the controller turns off the eighth switching tube and turns on the seventh switching tube to discharge the fourth inductor and increase the voltage of the first capacitor.

In order to enlarge the adjustable range of the voltage of the direct current port of the conversion circuit when processing three-phase electricity, the conversion circuit can also comprise a third switch, and the third switch is connected between the zero line interface and the first capacitor. The controller may also turn on the third switch when processing single-phase power and turn off the third switch when processing three-phase power.

In order to protect the conversion circuit, in one possible implementation, the conversion circuit may further include a fourth switch, a fifth switch, and a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode. One end of the fourth switch is connected with the cathode of the first diode, the cathode of the second diode and the cathode of the third diode respectively, and the other end of the fourth switch is connected with the high-potential end of the direct-current port; the anode of the first diode is connected with the cathode of the fourth diode, the anode of the second diode is connected with the cathode of the fifth diode, and the anode of the third diode is connected with the cathode of the sixth diode; one end of the fifth switch is connected with the anode of the fourth diode, the anode of the fifth diode and the anode of the sixth diode respectively, and the other end of the fourth switch is connected with the low-potential end of the direct-current port.

In this case, the controller may further turn on the fourth switch and the fifth switch when the single-phase or three-phase power is converted into the direct current; the fourth switch and the fifth switch are turned off when the direct current is converted into single-phase power or three-phase power.

In a third aspect, an embodiment of the present application provides an electronic device, which mainly includes the converter provided in any one of the second aspects. For example, the electronic device may be a new energy vehicle, a smart vehicle, a networked vehicle, or the like, the converter may be an onboard charger, and the conversion circuit may be a power factor correction circuit in the onboard charger.

These and other aspects of the present application will be more readily apparent from the following description of the embodiments.

Drawings

FIG. 1a is a schematic voltage swing of a single phase power;

FIG. 1b is a schematic diagram of voltage fluctuations for a three-phase power;

FIG. 2 is a schematic diagram of a single three-phase compatible AC converter;

FIG. 3 is a schematic diagram of a single three-phase compatible switching circuit;

FIG. 4a is a schematic diagram of an equivalent circuit structure of the converter circuit when processing single-phase power;

FIGS. 4b to 4e are schematic diagrams of the switching states of the conversion circuit when processing single-phase power;

FIG. 5a is a schematic diagram of an equivalent circuit configuration of the inverter circuit when processing three-phase power;

5 b-5 g are schematic diagrams of the switching states of the conversion circuit when processing three-phase power;

fig. 6 is a schematic structural diagram of a converter according to an embodiment of the present application;

fig. 7a is a schematic structural diagram of a first conversion circuit according to an embodiment of the present disclosure;

fig. 7b is a schematic diagram of a second conversion circuit structure according to an embodiment of the present disclosure;

fig. 7c is a schematic structural diagram of a third conversion circuit according to an embodiment of the present application;

fig. 8 is a schematic diagram of an equivalent circuit structure of a conversion circuit when processing single-phase power according to an embodiment of the present application;

fig. 9a and 9b are schematic diagrams of switching states of the conversion circuit provided by the embodiment of the present application when processing single-phase power;

fig. 10 is a schematic diagram of an equivalent circuit structure of a conversion circuit when processing three-phase power according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of a fourth conversion circuit according to an embodiment of the present application;

fig. 12a and 12b are schematic diagrams of switching states of a conversion circuit provided in an embodiment of the present application when the voltages of the first capacitor and the second capacitor are adjusted;

fig. 13a and 13b are schematic diagrams of switching states of a conversion circuit provided in an embodiment of the present application when the voltages of the first capacitor and the second capacitor are adjusted;

fig. 14 is a schematic structural diagram of a fourth conversion circuit according to an embodiment of the present application;

fig. 15a and 15b are schematic diagrams of switching states of the conversion circuit when the voltage of the first capacitor and the voltage of the second capacitor are adjusted according to the embodiment of the present application;

fig. 16a and 16b are schematic diagrams of switching states of the conversion circuit when the voltage of the first capacitor and the voltage of the second capacitor are adjusted according to the embodiment of the present application;

fig. 17 is a schematic structural diagram of a fifth conversion circuit according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more clear, the present application will be further described in detail with reference to the accompanying drawings. The particular methods of operation in the method embodiments may also be applied to apparatus embodiments or system embodiments. It is to be noted that "at least one" in the description of the present application means one or more, where a plurality means two or more. In view of this, the "plurality" may also be understood as "at least two" in the embodiments of the present invention. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" generally indicates that the preceding and following related objects are in an "or" relationship, unless otherwise specified. In addition, it is to be understood that the terms first, second, etc. in the description of the present application are used for distinguishing between the descriptions and not necessarily for describing a sequential or chronological order.

It is to be noted that "connected" in the embodiments of the present application may be understood as an electrical connection, and the connection of two electrical components may be a direct or indirect connection between the two electrical components. For example, a and B may be connected directly, or a and B may be connected indirectly through one or more other electrical elements, for example, a and B may be connected, or a and C may be connected directly, or C and B may be connected directly, and a and B are connected through C.

It should be noted that the switch tube and the switch in the embodiment of the present application may be one or more of various types of switch tubes such as a relay, a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), a Bipolar Junction Transistor (BJT), an Insulated Gate Bipolar Transistor (IGBT), etc., which are not listed in the embodiment of the present application. Each of the switching tubes may include a first electrode, a second electrode, and a control electrode, wherein the control electrode is used for controlling the switching tubes to be turned on or off. When the switching tube is switched on, current can be transmitted between the first electrode and the second electrode of the switching tube, and when the switching tube is switched off, current cannot be transmitted between the first electrode and the second electrode of the switching tube. Taking the MOSFET as an example, the control electrode of the switching tube is a gate, the first electrode of the switching tube may be a source of the switching tube, and the second electrode may be a drain of the switching tube, or the first electrode may be a drain of the switching tube, and the second electrode may be a source of the switching tube.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

The ac-dc converter can convert ac power into dc power, and is often used in electronic devices powered by ac power, such as new energy vehicles, home appliances, and industrial production lines. The dc-ac converter converts dc power into ac power, and is often used as a grid-connected device of a power generation system, and converts dc power generated by the power generation system into ac power through the dc-ac converter, so that the ac power can be transmitted through an ac power grid. For example, in photovoltaic, hydraulic, wind power generation systems, dc-ac converters are often used.

For convenience of description, the embodiments of the present application will be described below with reference to an ac converter. It should be noted that the ac converter may be an ac-dc converter, a dc-ac converter, or a converter having both ac-dc conversion and dc-ac conversion, and the present embodiment is not limited thereto.

At present, the common alternating current in the commercial power mainly comprises single-phase electricity and three-phase electricity. Fig. 1a shows an exemplary voltage waveform diagram of a single-phase power, and as shown in fig. 1a, the voltage of the single-phase power fluctuates in a periodic sine wave, and in china, the fluctuation amplitude of the single-phase power is generally ± 311V, and the fluctuation frequency is 50 Hz. That is, the peak value of the single-phase power is 311V, and the effective voltage of the single-phase power is

Fig. 1b shows an exemplary voltage waveform diagram of a three-phase power. As shown in fig. 1B, the three-phase power mainly includes three single-phase powers with offset phases, i.e., an a-phase power, a B-phase power, and a C-phase power as shown in fig. 1B. Each single-phase power wave is a periodic sine wave with the same amplitude (mostly +/-311V in China) and the same frequency (mostly 50Hz in China). In three-phase power, each phase of power is 120 ° out of phase with the other two. For example, at a certain time, the phase of the a-phase power is 0, the phase of the B-phase power is 120 °, and the phase of the C-phase power is 240 ° (i.e., -120 °).

Because single-phase electricity and three-phase electricity are the commonly used alternating current in the commercial power, therefore, can realize that single three-phase compatible exchanges converter has extensive application prospect. Figure 2 schematically shows a single three-phase compatible ac converter architecture,

as shown in fig. 2, the ac converter 20 mainly includes a conversion circuit 21 and a controller 22. Specifically, the method comprises the following steps:

conversion circuit 21

The conversion circuit 21 may receive the input voltage Vi, perform voltage conversion on the input voltage Vi, and output an output voltage Vo. When the converter circuit 21 performs ac-dc conversion, the input voltage Vi is an ac voltage, and when the converter circuit 21 performs dc-ac conversion, the input voltage Vi is a dc voltage and the output voltage Vi is an ac voltage. The conversion circuit 21 includes a dc port, and in the ac-dc conversion process, the dc port of the conversion circuit 21 may output a dc voltage, and in the dc-ac conversion process, the dc port of the conversion circuit 21 may receive the dc voltage.

Fig. 3 is a schematic diagram of a single three-phase compatible converting circuit 21. As shown in fig. 3, the conversion circuit 21 mainly includes an interface PA, an interface PB, an interface PC, and an interface PN, where the interface PA can transmit a-phase power, the interface PB can transmit B-phase power, the interface PC can transmit C-phase power, and the interface PN can be connected to a zero line to form a current loop.

In some scenarios, the conversion circuit 21 may further include an inductor LA, an inductor LB, an inductor LC, and an inductor LN, where the four inductors are connected to the four interfaces in a one-to-one correspondence. Specifically, one end of inductor LA is connected to interface PA, one end of inductor LB is connected to interface PB, one end of inductor LC is connected to interface PC, and one end of inductor LN is connected to interface PN. The inductor LA, the inductor LB, the inductor LC and the inductor LN can prevent the ac side and the dc port of the converter circuit 21 from being short-circuited, and can also filter the current transmitted by the converter circuit 21.

The conversion circuit 21 further includes a bridge conversion circuit mainly including three bridge arms. Specifically, the first arm of the bridge type switching circuit includes a switching tube S11 and a switching tube S12 connected in series, and the second electrode of the switching tube S11 is connected to the first electrode of the switching tube S12. The second bridge arm comprises a switching tube S21 and a switching tube S22 which are connected in series, and the second electrode of the switching tube S21 is connected with the first electrode of the switching tube S22. The third bridge arm comprises a switching tube S31 and a switching tube S32 which are connected in series, and the second electrode of the switching tube S31 is connected with the first electrode of the switching tube S32. The switching tube S11, the switching tube S21 and the switching tube S31 are connected at first electrodes thereof, and the switching tube S12, the switching tube S22 and the switching tube S32 are connected at second electrodes thereof.

Generally, the conversion circuit 21 may further include a capacitor Ca. One end of the capacitor Ca is connected to the high potential end of the dc port, and the other end of the capacitor Ca is connected to the low potential end of the dc port. The capacitor Ca may filter the output voltage Vo during the ac-dc conversion, and may filter the input voltage Vi during the dc-ac conversion.

Three bridge arms of the bridge type conversion circuit are respectively connected with the inductor LA, the inductor LB and the inductor LC in a one-to-one corresponding mode. Specifically, the other end of the inductor LA is connected to the second electrode of the switching tube S11, the other end of the inductor LB is connected to the second electrode of the switching tube S21, and the other end of the inductor LC is connected to the second electrode of the switching tube S31.

To be compatible with single-phase and three-phase power, the conversion circuit 21 may further include a switch Ka and a switch Kb. The first electrode of the switch Ka is connected with the interface PA, and the second electrode of the switch Ka is connected with the interface PB. A first electrode of the switch Kb is connected to one end of the inductor Lc close to the bridge conversion circuit, and a second electrode of the switch Kb is connected to the other end of the inductor LN far from the interface PN.

Next, based on the conversion circuit shown in fig. 3, the conversion process between single-phase power and three-phase power will be further described by taking an example of ac-dc conversion.

Single phase electrical conversion

When single-phase electric conversion is performed, the switch Ka and the switch Kb are turned on. At this time, the interface PA may be connected to the live wire, the interface PN may be connected to the zero line, the interface PB and the interface PC do not participate in current transmission, and the conversion circuit 21 may be equivalent to the circuit structure shown in fig. 4 a.

The interface PA and the interface PN may receive single-phase power, where the voltage of the interface PN is 0, and the voltage of the interface PA may be equivalent to the voltage of the single-phase power. The voltage variation of the single phase electricity can be as shown in fig. 1 a. Each cycle of the sine wave may be divided into a positive half cycle (a period of time in which the voltage is greater than 0) and a negative half cycle (a period of time in which the voltage is less than 0). Specifically, the method comprises the following steps:

1. during the positive half period, the states of the respective switching tubes in the switching circuit 21 can be as shown in fig. 4b, the switching tube S11, the switching tube S21 and the switching tube S32 are turned on, and the switching tube S31, the switching tube S12 and the switching tube S22 are turned off. The current is input from the interface PA, is transmitted in parallel through the inductor LA and the switch tube S11, and the inductor LB and the switch tube S21, and is output from the high potential end (+) of the direct current port. The returned current is input from the low potential end (-) of the direct current port, transmitted through the switch tube S32 and the inductor LN, and then output from the interface PN.

In this phase, the inductance LA and the inductance LB may prevent the ac side and the dc port of the converter circuit 21 from being short-circuited. In some scenarios, the inductor LA and the inductor LB may also be used for boosting. That is, before the switching transistors of the bridge converter circuit are set to the state shown in fig. 4b in the positive half cycle, the switching transistors of the bridge converter circuit may be set to the state shown in fig. 4c, that is, the switching transistor S11, the switching transistor S21 and the switching transistor S31 are turned off, and the switching transistor S12, the switching transistor S22 and the switching transistor S32 are turned on.

As shown in fig. 4c, current is input from the interface PA, transmitted in parallel through the inductor LA and the switch tube S12, and the inductor LB and the switch tube S22, and then transmitted through the switch tube S32 and the inductor LN, and then output from the interface PN. At this time, the inductance LA and the inductance LB charge. Then, by setting the state of each switching tube as shown in fig. 4b, the inductor LA and the inductor LB can be discharged, so that the voltage of the dc port is increased to achieve boosting. The voltage of the direct current port can be adjusted by adjusting the charging time and the discharging time of the inductor LA and the inductor LB.

2. In the negative half period, the states of the switching tubes in the bridge converting circuit can be as shown in 4d, the switching tube S31, the switching tube S12 and the switching tube S22 are turned on, and the switching tube S32, the switching tube S11 and the switching tube S21 are turned off. The current is input from the interface PN, is output from the high potential end (+) of the direct current port after being transmitted by the inductor LN and the switch tube S31, and the backflow current is input from the low potential end (-) of the direct current port, is output from the interface PA after being transmitted in parallel by the switch tube S12, the inductor LA, the switch tube S22 and the inductor LB.

In this phase, the inductance LA and the inductance LB may prevent the ac side and the dc port of the converter circuit 21 from being short-circuited. In some scenarios, the inductor LA and the inductor LB may also be used for boosting. That is, in the negative half cycle, before the switching tubes of the bridge converting circuit are set to the state shown in fig. 4d, the switching tubes of the switching circuit may be set to the state shown in fig. 4e, that is, the switching tube S12, the switching tube S22 and the switching tube S32 are turned off, and the switching tube S11, the switching tube S21 and the switching tube S31 are turned on.

As shown in fig. 4e, the current is input from the interface PN, transmitted through the inductor LN and the switch tube S31, and then transmitted in parallel through the switch tube S11 and the inductor LA, and the switch tube S21 and the inductor LB, respectively, and then output from the interface PA. At this time, the inductance LA and the inductance LB charge. Then, the state of each switching tube is set as shown in fig. 4d, so that the inductor LA and the inductor LB can be discharged, the voltage of the dc port can be increased, and the voltage boosting can be realized. The voltage of the direct current port can be adjusted by adjusting the charging time and the discharging time of the inductor LA and the inductor LB.

In summary, in the process of ac-dc converting single-phase power, current is always output from the high potential terminal (+) of the dc port and input from the low potential terminal (-) of the dc port, that is, the potential of the high potential terminal (+) of the dc port is greater than the potential of the low potential terminal (-) of the dc port. And the low voltage difference between the high potential end (+) of the direct current port and the low potential end (-) of the direct current port is the output voltage Vo of the conversion circuit, therefore, the output voltage Vo can keep a positive value, namely, the output voltage Vo is the direct current voltage, thereby realizing the alternating current-direct current conversion.

Three-phase power conversion

When the three-phase power conversion is performed, the switch Ka and the switch Kb are turned off. At this time, interface PA may be connected to phase line a, interface PB may be connected to phase line B, interface PC may be connected to phase line C, and interface PN does not transmit current. The phase line A is used for transmitting phase electricity A, the phase line B is used for transmitting phase electricity B, and the phase line C is used for transmitting phase line C. The conversion circuit 21 may be equivalent to the circuit configuration shown in fig. 5 a.

The voltage variation of the three-phase power can be divided into 6 time periods (time periods t1 to t6) in each cycle of the sine wave as shown in fig. 1b, and the maximum phase voltage or the minimum phase voltage in any two time periods are different from each other. Specifically, the method comprises the following steps:

1. during time period t1, the phase voltage of the a-phase electricity is the largest and the phase voltage of the B-phase electricity is the smallest.

In this stage, the state of each switch tube can be as shown in fig. 5b, switch tube S11 and switch tube S22 are turned on, and switch tube S12, switch tube S21, switch tube S31 and switch tube S32 are turned off. The current is input from the interface PA, passes through the inductor LA and the switching tube S11, and is output from the high potential end (+) of the direct current port. The return circuit is input from the low potential terminal (-) of the dc port, passes through the switching tube S22 and the inductor LB, and is output from the interface PB.

2. During time period t2, the phase voltage of the a-phase electricity is the largest and the phase voltage of the C-phase electricity is the smallest.

In this stage, the state of each switch tube can be as shown in fig. 5c, switch tube S11 and switch tube S32 are turned on, and switch tube S12, switch tube S21, switch tube S31 and switch tube S22 are turned off. The current is input from the interface PA, passes through the inductor LA and the switching tube S11, and is output from the high potential end (+) of the direct current port. The return current circuit is input from the low potential terminal (-) of the dc port, passes through the switching tube S32 and the inductor LC, and is output from the interface PC.

3. During time period t3, the phase voltage of the B-phase electricity is the largest and the phase voltage of the C-phase electricity is the smallest.

In this stage, the state of each switch tube can be as shown in fig. 5d, switch tube S21 and switch tube S32 are turned on, and switch tube S11, switch tube S12, switch tube S22 and switch tube S32 are turned off. The current is input from the interface PB, passes through the inductor LB and the switching tube S21, and is output from the high potential terminal (+) of the dc port. The return current circuit is input from the low potential terminal (-) of the dc port, passes through the switching tube S32 and the inductor LC, and is output from the interface PC.

4. During time period t4, the phase voltage of the B-phase electricity is the largest and the phase voltage of the a-phase electricity is the smallest.

In this stage, the state of each switch tube can be as shown in fig. 5e, switch tube S12 and switch tube S21 are turned on, and switch tube S11, switch tube S22, switch tube S31 and switch tube S32 are turned off. The current is input from the interface PB, passes through the inductor LB and the switching tube S21, and is output from the high potential terminal (+) of the dc port. The return circuit is input from the low potential terminal (-) of the dc port, passes through the switch tube S12 and the inductor LA, and is output from the interface PA.

5. During time period t5, the phase voltage of the C-phase electricity is maximum and the phase voltage of the a-phase electricity is minimum.

In this stage, the state of each switch tube can be as shown in fig. 5f, switch tube S12 and switch tube S31 are turned on, and switch tube S11, switch tube S21, switch tube S22 and switch tube S32 are turned off. The current is input from the interface PC, passes through the inductor LC and the switching tube S31, and is output from the high potential end (+) of the direct current port. The return circuit is input from the low potential terminal (-) of the dc port, passes through the switch tube S12 and the inductor LA, and is output from the interface PA.

6. During time period t6, the phase voltage of the C-phase electricity is the largest and the phase voltage of the B-phase electricity is the smallest.

In this stage, the state of each switch tube can be as shown in fig. 5g, switch tube S31 and switch tube S22 are turned on, and switch tube S12, switch tube S12, switch tube S21 and switch tube S32 are turned off. The current is input from the interface PC, passes through the inductor LC and the switching tube S31, and is output from the high potential end (+) of the direct current port. The return circuit is input from the low potential terminal (-) of the dc port, passes through the switching tube S22 and the inductor LB, and is output from the interface PB.

It can be understood that, in the above 6 time periods, at least two of the inductor LA, the inductor LB, and the inductor LC may be charged first, and then set to the switching states shown in fig. 5b to 5g, so as to discharge the inductor, thereby implementing the voltage boosting. The specific boosting principle is similar to that of single-phase power, and details thereof are omitted.

In summary, in the process of ac-dc converting three-phase power, current is always output from the high potential terminal (+) of the dc port and input from the low potential terminal (-) of the dc port, that is, the potential of the high potential terminal (+) of the dc port is greater than the potential of the low potential terminal (-) of the dc port. Therefore, the output voltage Vo can be kept positive, i.e., the output voltage Vo is a dc voltage, thereby realizing ac-dc conversion.

Controller 22

The controller 22 can be connected to the control electrode of the switch Ka, the control electrode of the switch Kb in the switching circuit 21, and the control electrodes of the respective switching tubes in the bridge switching circuit. The controller 22 can provide the same or different control signals for the switches and the switching tubes, so as to control the on and off of the switches and the switching tubes in the converting circuit 21, respectively, so that the converting circuit 21 can implement the above voltage conversion.

For example, the controller 12 may be a logic circuit capable of generating a control signal, for example, the controller 12 may be an Electronic Control Unit (ECU), a general-purpose Central Processing Unit (CPU), a general-purpose processor, a Digital Signal Processing (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a microcontroller (microcontroller unit, MCU), or other programmable logic device, transistor logic device, hardware component, or any combination thereof.

Although the conversion circuit 21 shown in fig. 3 can realize both ac-dc conversion of single-phase power and ac-dc conversion of three-phase power, the problem of large difference in voltage between dc ports in different scenarios is faced during specific design. The voltage at the dc port is also often referred to as the bus voltage. It is to be understood that the voltage at the dc port may be an input voltage (dc-ac conversion process) or an output voltage (ac-dc conversion process), and the embodiment of the present application is not limited thereto.

Specifically, when the converter circuit 21 processes single-phase electricity, although the effective value of the single-phase electricity is 220V, the effective value of the single-phase electricity may reach 265V due to grid fluctuations and the like. At this time, the dc port voltage of the conversion circuit 21 can be reached

When the converter circuit 21 is designed, the dc port voltage applied to the converter circuit 21 should be not less than 375V, and considering that the converter circuit 21 has a boosting function, 375V can be understood as the minimum voltage of the dc port, so the converter circuit 21 is usually designed according to the voltage of the dc port being as low as 400V. For example, the switching tube, the inductor LA, the inductor LB, and the inductor LC in the bridge converter circuit are selected according to the voltage at the dc port of 400V.

It should be noted that the conversion circuit 21 processes single-phase electricity, and may be understood that the conversion circuit 21 converts the single-phase electricity into direct current, or may be understood that the conversion circuit 21 converts the direct current into the single-phase electricity. Similarly, the converting circuit 21 processes three-phase power, which may be understood as the converting circuit 21 converting three-phase power into direct current, or may be understood as the converting circuit 21 converting direct current into three-phase power. And will not be described in detail later.

When the conversion circuit 21 processes three-phase electricity, the effective value of the line voltage between the three phase lines can be reached

The three-phase line is three lines for respectively transmitting A-phase electricity, B-phase electricity and C-phase electricity. The line voltage is the voltage between any two phase lines. When the effective value of the line voltage is 459V, the peak value of the line voltage is 649V (459 x V2 is 649V), that is, the voltage of the dc port may reach 649V. When designing the converter circuit 21, the dc port voltage applied to the converter circuit 21 should be not less than 649V, and generally, considering that the converter circuit 21 has a boosting function, 649V can be understood as the minimum voltage of the dc port, and the converter circuit 21 can be designed according to the minimum voltage of the dc port being 800V. For example, the switching tube, the inductor LA, the inductor LB, and the inductor LC in the bridge converter circuit are selected according to the voltage at the dc port of 800V.

As can be seen, the design criteria of the inverter circuit 21 handling single-phase power and the inverter circuit 21 handling three-phase power are different. When the conversion circuit 21 needs to realize compatibility between single-phase electricity and three-phase electricity, if the conversion circuit 21 is designed according to a dc port voltage of 800V, the switching tube loss and the inductance-magnetic loss in the conversion circuit 21 are large when the conversion circuit 21 processes the single-phase electricity. If the converter circuit 21 is designed according to the dc port voltage of 400V, the converter circuit 21 may damage the switching tube of the converter circuit 21 due to excessive overshoot current in the process of processing three-phase power.

In summary, the current single-phase and three-phase compatible converter circuit still has the problem of large voltage difference of the dc port, which is not favorable for further improving the performance of the converter circuit. In view of this, embodiments of the present application provide a conversion circuit and a converter, which can reduce the voltage difference of the dc port of the conversion circuit when processing three-phase power and single-phase power respectively, and thus are beneficial to improving the performance of the conversion circuit.

As shown in fig. 6, the converter 60 mainly includes a conversion circuit 61 and a controller 62. The specific implementation of the controller 62 is similar to that of the controller 22, and the detailed description thereof is omitted. The conversion circuit 61 can realize both ac-dc conversion and dc-ac conversion.

Illustratively, as shown in fig. 7a, the conversion circuit 61 mainly includes an interface PA, an interface PB, an interface PC, an interface PN, a bidirectional switch K1, a bridge conversion circuit 611, a dc capacitor C1, and a dc capacitor C2. The bridge circuit 611 includes three bridge arms, and the specific structure is similar to that described above, which is not described herein again.

When single-phase electricity is processed, the interface PA can be connected with a live wire, and the interface PN can be connected with a zero line. When processing three-phase electricity, interface PA can connect A looks line, and interface PB can connect B looks line, and interface PC can connect C looks line. The A-phase line can transmit A-phase electricity, the B-phase line can transmit B-phase electricity, and the C-phase line can transmit C-phase electricity.

As shown in fig. 7a, the interface PA is connected to the first leg of the bridge switching circuit 611. The first end of the bidirectional switch K1 is connected to the second leg of the bridge switching circuit 611, the second end of the bidirectional switch K1 is connected to the interface PA, and the second end of the bidirectional switch K1 is connected to the interface PB.

A capacitor C1 and a capacitor C2 are connected in series between a high potential terminal (+) and a low potential terminal (-) of the dc port of the conversion circuit 61, wherein one end of the capacitor C1 is connected to the high potential terminal (+) of the dc port, the other end of the capacitor C1 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the low potential terminal (+) of the dc port. The interface PN is connected between the capacitor C1 and the capacitor C2.

Similar to the conversion circuit 21, in one possible implementation, as shown in fig. 7b, the conversion circuit 61 may further include an inductor LA, an inductor LB, and an inductor LC. One end of the inductor LA is connected to the interface PA, and the other end of the inductor LA is connected to the first bridge arm in the bridge conversion circuit 611. One end of the inductor LB is connected to the first end of the bi-directional switch K1, and the other end of the inductor LB is connected to the second leg of the bridge switching circuit 611. One end of the inductor LC is connected to the interface PC, and the other end of the inductor LC is connected to the third leg of the bridge switching circuit 611.

By providing the inductance LA, the inductance LB, and the inductance LC, the conversion circuit 611 can be prevented from being short-circuited, so that the conversion circuit 611 can be protected. In some scenarios, the inductor LA, the inductor LB, and the inductor LC may also be used to implement boosting, and detailed implementation is not described again.

Next, without considering the boost voltage, the application scenarios of single-phase power and three-phase power will be described:

scene one: processing single-phase electricity

When processing single-phase power, the controller 62 may control the bi-directional switch K1 to connect the interface PA to the second leg of the bridge conversion circuit 611. In this case, the conversion circuit 61 may be equivalent to the circuit configuration shown in fig. 8.

Taking the ac-dc conversion process as an example, the interface PA and the interface PN may receive single-phase power. The voltage variation of the single phase electricity can be as shown in fig. 1 a. Each cycle of the sine wave may be divided into a positive half cycle (a period of time in which the voltage is greater than 0) and a negative half cycle (a period of time in which the voltage is less than 0). Specifically, the method comprises the following steps:

1. during the positive half period, the states of the switches in the bridge converting circuit can be as shown in fig. 9a, the switch S11 and the switch S21 are turned on, and the switch S12 and the switch S22 are turned off. The switch tube S31 and the switch tube S32 may be either on or off.

The current is input from the interface PA, transmitted by the switch tube S11 and the switch tube S21, and output from the high potential end (+) of the direct current port. The returned current is transmitted from the low potential end of the capacitor C1 to the interface PN and then is output. In the process, since the other end of the capacitor C1 is connected to the interface PN and one end of the capacitor C1 is connected to the high potential end (+) of the dc port, the voltage Vc1 across the capacitor C1 can reach the peak Vmax of the single-phase power.

It should be noted that in the embodiment of the present invention, the current only passes through two switching tubes (S11 and S21), and compared with the converting circuit 21, the current in the embodiment of the present invention does not need to pass through the switching tube S32. That is, the inverter circuit 21 operates in a full-bridge mode when processing the electrical phase power, whereas the inverter circuit 61 provided by the present application operates in a half-bridge mode. The switching circuit 61 provided in the embodiment of the present application is also advantageous to reduce loss because current passes through one switching tube less.

2. In the negative half period, the state of each switch tube in the bridge converting circuit can be as shown in fig. 9b, switch tube S12 and switch tube S22 are conductive, and switch tube S11 and switch tube S21 are disconnected. The switch tube S31 and the switch tube S32 may be either on or off.

The current is input from the interface PN and transmitted to the high potential terminal of the capacitor C2. The returned current is output from the low potential end of the capacitor C2, and is transmitted to the inductor LA and the inductor LB through the switch tube S12 and the switch tube 22, respectively, and then is output from the interface PA.

In the process, one end of the capacitor C2 is connected with the interface PN, and the other end of the capacitor C2 is connected with the low potential end (-) of the dc port, so that the voltage Vc2 across the capacitor C2 can reach the peak Vmax of single-phase power.

Similar to the positive half cycle, the switching circuit 61 also operates in the half-bridge mode during the negative half cycle, thereby also contributing to the reduction of losses.

Through the above process, single-phase electricity can be converted into direct current. The process of converting direct current into single-phase current is similar to the above process principle, and is not described again.

Since the voltage of the capacitor C1 and the voltage of the capacitor C2 both reach Vmax, the voltage of the dc port can reach 2Vmax when processing single-phase power. Assuming that the peak value Vmax of the single-phase power is 375V (effective value 265V), the voltage of the dc port may reach 730V when the conversion circuit 61 processes the single-phase power.

Scene two: treating three-phase electricity

When processing three-phase power, the controller 62 may control the bidirectional switch K1 to connect the second leg of the bridge conversion circuit 611 to the interface PB. In this case, the conversion circuit 61 may be equivalent to the circuit configuration shown in fig. 10. The processing procedure of the three-phase power by the conversion circuit 61 is similar to that of the conversion circuit 21, and is not described in detail.

As before, when the converter circuit 61 processes three-phase power, the voltage of the dc port may reach 649V, so the converter circuit 61 is generally designed to 800V. When the conversion circuit 61 provided in the embodiment of the present application processes single-phase power, the voltage at the dc port is twice as high as the voltage at the dc port of the conversion circuit 21, which may reach 730V. That is, when the converter circuit 61 processes single-phase power, the minimum voltage on the dc side is 730V. In the design standard of the switching circuit 61 in the single-phase electric field scene, the voltage on the dc side should be greater than 730V. Therefore, when the conversion circuit 61 processes single-phase electricity and three-phase electricity, the minimum voltage of the direct current port is closer, so that the conversion circuit 61 can be designed according to the uniform voltage (800V) of the direct current port, and the performance of the conversion circuit 61 is further improved while single-phase and three-phase compatibility is realized.

It should be noted that designing the conversion circuit 61 with a uniform voltage (800V) of the dc port in the embodiment of the present application does not mean that the conversion circuit 61 has a uniform voltage of the dc port when processing single-phase power and three-phase power. The voltage at the dc port of the conversion circuit 61 may be of a magnitude that depends on the actual application requirements of the circuit to which the dc port is connected.

For example, the converter 60 may be an On Board Charger (OBC). The conversion circuit 61 may be used as a PFC circuit in the OBC, and the conversion circuit 61 may receive the ac power, perform ac-dc conversion, and output the dc power through the dc port. The DC port of the conversion circuit 61 may be connected to a conversion circuit 63, and the conversion circuit 63 may be a Direct Current-Direct Current (DC-DC). The voltage at the dc port of the converting circuit 61, i.e. the magnitude of the output voltage of the converting circuit 61, should be adapted to the operating voltage range of the converting circuit 63.

Moreover, since the voltage of the dc port is closer when the conversion circuit 61 processes single-phase power and three-phase power in the embodiment of the present application, it is also advantageous to simplify the design of the conversion circuit 63 connected to the conversion circuit 61.

In one possible implementation, as shown in fig. 11, the conversion circuit 61 may further include a switch K3. One end of the switch K3 is connected with the interface PN, and the other end of the switch K3 is connected between the capacitor C1 and the capacitor C2. The controller 62 may also open the switch K3 when processing three-phase power.

Specifically, if the interface PN is connected to the capacitor C1 and the capacitor C2, the voltage Vc1 of the capacitor C1 may reach the peak value of the phase voltage in the three-phase power, that is, 375V. Similarly, the voltage Vc2 of the voltage Vc2 of the capacitor C2 may reach 375V. Therefore, the voltage of the dc port can reach 730V.

If the PN is disconnected from the capacitor C1 and the capacitor C2, the voltage at the DC port is greater than or equal to the peak value of the line voltage. As before, the peak of the line voltage may reach 649V, so after the switch tube K3 is turned off, the voltage of the dc port may be reduced to 649V. Therefore, when three-phase power is processed, the switch K3 disconnects the interface PN from the capacitor C1 and the capacitor C2, which is beneficial to reducing the minimum voltage of the dc port (by 15%), and is further beneficial to increasing the regulation range of the output voltage of the conversion circuit 61.

When the converter 60 is an OBC, the conversion circuit 63 is often used to perform dc-dc step-down conversion. The lower the voltage at the dc port of the converter circuit 61, the lower the input voltage of the converter circuit 63, which is advantageous for reducing the transformation ratio (input voltage/output voltage) of the converter circuit 63, thereby improving the efficiency of the converter circuit 63 and outputting a lower voltage from the converter circuit 63.

As described above, the converter circuit 61 provided in the embodiment of the present application increases the minimum voltage of the dc port when processing single-phase power. It is understood that the capacitor C1 and the capacitor C2 tend to have some difference in electrical properties due to process limitations and the like. In the case of a fixed voltage at the dc port, there is a risk that one of the capacitors will have too high a voltage and the other capacitor will have too low a voltage, which may cause damage to the capacitors.

In view of this, when the controller 62 processes single-phase power, the voltages of the capacitor C1 and the capacitor C2 can be dynamically adjusted by controlling the on and off of the switch tube S31 and the switch tube S32, so that the voltages of the capacitor C1 and the capacitor C2 are kept equal. It should be noted that the process of the controller 62 adjusting the voltages of the capacitor C1 and the capacitor C2 and the process of the controller 62 processing single-phase electricity are independent of each other, and may be performed simultaneously or in time-sharing manner, which is not limited in this embodiment of the application.

For example, as shown in fig. 6, the converter 60 may further include a detection circuit 64, the detection circuit 64 is connected to the dc port of the conversion circuit 61, and may respectively detect a voltage Vc1 across the capacitor C1 and a voltage Vc2 across the capacitor C2. The converter 60 may determine whether it is necessary to start or stop adjusting the voltage Vc1 and the voltage Vc2 according to the detected voltage Vc1 and the voltage Vc 2.

In one possible implementation, as shown in fig. 7c, the conversion circuit 61 may further include a bidirectional switch K2. The first end of the bidirectional switch K2 is connected to the third leg of the bridge switching circuit 611, the second end of the bidirectional switch K2 is connected to the interface PC, and the second end of the bidirectional switch K2 is connected to the interface PN. When processing single-phase power, the controller 62 may control the connection between the bidirectional switch K2 conduction inductor LC and the interface PN, and when processing three-phase power, the controller 62 may control the connection between the bidirectional switch K2 conduction inductor LC and the interface PC.

Illustratively, as shown in fig. 8, the inductor LC is connected to the interface PN when processing single-phase power, so that the controller 52 can adjust the voltage Vc1 of the capacitor C1 and the voltage Vc2 of the capacitor C2 through the inductor LC, the switch tube S31 and the switch tube S32. Specifically, the method comprises the following steps:

when Vc1> Vc2, as shown in fig. 12a, the controller 62 may turn on the switch tube S31, turn off the switch tube S32, and output the current from the high potential end of the capacitor C1, and charge the inductor LC after the current is transmitted through the switch tube S31, during which the capacitor C1 discharges continuously and the voltage Vc1 decreases gradually.

After the inductor LC is charged for a period of time, the switching tube S31 is opened. As shown in fig. 12b, the inductor LC is discharged, and the current is output from the end of the LC close to the interface PN and transmitted to the high potential end of the capacitor C2, so as to charge the capacitor C2, and the voltage Vc2 is gradually increased.

The controller 62 may turn on and off the switching tubes S31 and S32 repeatedly over one or more cycles to gradually approach the voltages Vc1 and Vc2 until Vc1 becomes Vc 2.

When Vc1< Vc2, as shown in fig. 13a, the controller 62 may turn on the switch tube S32, turn off the switch tube S31, and output the current from the high potential end of the capacitor C2, and return the current to the low potential end of the capacitor C2 after the current is transmitted through the inductor LC and the switch tube S31. In the process, the inductor LC is charged, the capacitor C2 is continuously discharged, and the Vc2 is gradually reduced.

After the inductor LC is charged for a certain time, the switch tube S32 is turned off, and the switch tube S31 is turned on. As shown in fig. 13b, the inductor LC is discharged, and the current is output from the end of the inductor LC connected to the third leg, and is transmitted to the high potential end of the capacitor C1 through the switching tube S31, so as to charge the capacitor C1, and the voltage Vc1 is gradually increased.

The controller 62 may turn on and off the switch tube S31 and the switch tube S32 repeatedly for one or more cycles to gradually approach the voltages Vc1 and Vc2 until the voltage Vc1 becomes equal to the voltage Vc 2.

In another possible implementation, as shown in fig. 14, the conversion circuit 61 may further include a bidirectional switch K6. The first end of the bidirectional switch K6 is connected with one end of the inductor LC far away from the third bridge arm, the second end of the bidirectional switch K6 is connected with the first end of the bidirectional switch K1, and the third end of the bidirectional switch K6 is connected with the interface PC. When processing single-phase power, the controller 62 may control the bidirectional switch K6 to turn on the connection between the first end of the bidirectional switch K1 and the inductor LC, and control the bidirectional switch K1 to turn on the connection between the interface PA and the inductor LB, that is, paths between the interface PA and the inductor LA, the inductor LB, and the inductor LC may all be turned on (as shown in fig. 15 a), and the inductor LA, the inductor LB, and the inductor LC may transmit the single-phase power received by the interface PA in parallel. Thus, this implementation is advantageous for the converter circuit 61 to be suitable for single-phase power at higher powers.

In order to maintain the regulation capability of the voltage Vc1 and the voltage Vc2, as shown in fig. 14, the bridge conversion circuit 611 may further include a fourth bridge arm, and the fourth bridge arm may include a switch tube S41 and a switch tube S42. The conversion circuit 61 may further include an inductor LN, one end of which is connected to the fourth leg, and the other end of which is connected between the capacitor C1 and the capacitor C2. The controller 62 can adjust the voltages across the capacitor C1 and the capacitor C2 by controlling the fourth leg and the inductor LN.

Specifically, as shown in fig. 14, in the fourth arm, the first electrode of the switching tube S41 is connected to the high potential terminal (+) of the dc port, the second electrode of the switching tube S41 is connected to the first electrode of the switching tube S42, and the second electrode of the switching tube S42 is connected to the low potential terminal (-) of the dc port. One end of inductor LN is connected to the first pole of switching tube S41.

When Vc1> Vc2, as shown in fig. 15a, the controller 62 may turn on the switch tube S41, turn off the switch tube S42, and output the current from the high potential end of the capacitor C1, and charge the inductor LN after the current is transmitted through the switch tube S41, during which the capacitor C1 discharges continuously and the voltage Vc1 decreases gradually.

After the inductor LN charges for a certain time, the switching tube S41 is opened. As shown in fig. 15b, the inductor LN is discharged, and current is output from the end of LN close to the capacitor C2 and transmitted to the high potential end of the capacitor C2, thereby charging the capacitor C2 and gradually increasing the voltage Vc 2.

The controller 62 may turn on and off the switching tubes S41 and S42 repeatedly over one or more cycles to gradually approach the voltages Vc1 and Vc2 until Vc1 becomes Vc 2.

When Vc1< Vc2, as shown in fig. 16a, the controller 62 may turn on the switch tube S42, turn off the switch tube S41, and output the current from the high potential end of the capacitor C2, and return the current to the low potential end of the capacitor C2 after the current is transmitted through the inductor LN and the switch tube S42. In the process, the inductor LN charges, the capacitor C2 continuously discharges, and the Vc2 gradually decreases.

After the inductor LN charges for a period of time, the switch tube S42 is turned off, and the switch tube S41 is turned on. As shown in fig. 16b, the inductor LN discharges, and the current is output from the end of the inductor LN connected to the fourth leg, and is transmitted to the high potential end of the capacitor C1 through the switching tube S41, so as to charge the capacitor C1, and the voltage Vc1 gradually increases.

The controller 62 may turn on and off the switch tube S41 and the switch tube S42 repeatedly for one or more cycles to gradually approach the voltages Vc1 and Vc2 until the voltage Vc1 becomes equal to the voltage Vc 2.

As described above, the converter 60 provided in the embodiment of the present application can implement both dc-ac conversion and ac-dc conversion. In one possible implementation, as shown in fig. 17, the conversion circuit 61 further includes a switch tube K4 and a switch tube K5, and diodes D1 to D6. One end of the switching tube K4 is connected to the cathodes of the diodes D1 to D3, respectively, and the other end of the switching tube K4 is connected to the high potential end (+) of the dc port. The anode of the diode D1 is connected to the cathode of the diode D4, the anode of the diode D2 is connected to the cathode of the diode D5, and the anode of the diode D3 is connected to the cathode of the diode D6. The anodes of the diodes D4 to D6 are connected to one end of the switching tube K5, and the other end of the switching tube K5 is connected to the low potential terminal (-) of the dc port.

The cathode of the diode D4 is further connected to the other end of the inductor LA, the cathode of the diode D5 is further connected to the other end of the inductor LB, and the cathode of the diode D6 is further connected to the other end of the inductor LC.

When the converter 60 performs ac-dc conversion, the controller 62 may turn on the switch transistor K4 and the switch transistor K5. The diode D1 and the diode D6 can prevent the converter circuit 61 from being damaged by sudden changes in the effective value of the voltage of the received alternating current. For example, at a certain time, the effective value of the line voltage of the three-phase power is 380V, and the output voltage of the dc port is 537V. Thereafter, the effective value of the line voltage of the three-phase power is abruptly increased to 459V, the peak value of which is as high as 649V. For the input voltage of the positive half cycle, the diode D1, the diode D2, and the diode D3 may be conductive, thereby directly outputting the excessively high input voltage. For the input voltage of the negative half cycle, the diode D4, the diode D5, and the diode D6 may be conductive, thereby directly outputting the excessively high input voltage. Therefore, the conversion circuit 61 can be protected by providing the switch K4, the switch K5, and the diodes D1 to D6.

When the converter 60 performs dc-ac conversion, the controller 62 may open the switch K4 and the switch K5. In this case, the diodes D1 to D6 are floating, and thus do not affect the conversion process of the converter 60.

Based on the same technical concept, embodiments of the present application further provide an electronic device, which includes the converter provided in any of the foregoing embodiments. Illustratively, the electronic device may be a smart car, a new energy car, an internet connection car, or the like.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A conversion circuit, comprising: the bridge type switching circuit comprises a first interface, a second interface, a third interface, a zero line interface, a first bidirectional switch, a bridge type switching circuit, a first capacitor and a second capacitor, wherein the bridge type switching circuit comprises three bridge arms;

the first interface is connected with a first bridge arm of the bridge type conversion circuit, and the first interface is used for connecting a live wire or a first phase wire;

the first end of the first bidirectional switch is connected with the second bridge arm of the bridge type conversion circuit, the second end of the first bidirectional switch is connected with the first interface, the third end of the first bidirectional switch is connected with the second interface, the second interface is used for connecting a second phase line, the first bidirectional switch is used for conducting the connection between the second bridge arm and the first interface when processing single-phase power, and conducting the connection between the second bridge arm and the second interface when processing three-phase power;

the third interface is connected with a third bridge arm of the conversion circuit and is used for connecting a third phase line;

the bridge type conversion circuit is used for converting single-phase power or three-phase power into direct current and outputting the direct current from a direct current port of the conversion circuit, or receiving the direct current through the direct current port and converting the direct current into the single-phase power or the three-phase power;

one end of the first capacitor is connected with the high potential end of the direct current port, the other end of the first capacitor is connected with one end of the second capacitor, the other end of the second capacitor is connected with the low potential end of the direct current port, the zero line interface is connected between the first capacitor and the second capacitor, and the zero line interface is used for connecting a zero line.

2. The conversion circuit of claim 1, further comprising a first inductor, a second inductor, and a third inductor;

the first inductor is connected between the first interface and the first bridge arm, the second inductor is connected between the first end of the first bidirectional switch and the second bridge arm, and the third inductor is connected between the third interface and the third bridge arm.

3. The converter circuit according to claim 2, further comprising a second bidirectional switch, wherein a first end of the second bidirectional switch is connected to an end of the third inductor remote from the third leg, a second end of the second bidirectional switch is connected to the third interface, and a third end of the second bidirectional switch is connected to the neutral interface;

and the second bidirectional switch is used for conducting the connection between the third inductor and the zero line interface when processing single-phase power and conducting the connection between the third interface and the zero line interface when processing three-phase power.

4. The converter circuit according to claim 2, further comprising a third bidirectional switch, wherein a first terminal of the third bidirectional switch is connected to a terminal of the third inductor remote from the third leg, a second terminal of the third bidirectional switch is connected to the first terminal of the first bidirectional switch, and a third terminal of the third bidirectional switch is connected to the third interface;

and the third bidirectional switch is used for conducting the connection between the first end of the first bidirectional switch and the third inductor when single-phase electricity is processed, and conducting the connection between the third interface and the third inductor when three-phase electricity is processed.

5. The conversion circuit of claim 4, wherein the bridge conversion circuit further comprises a fourth bridge leg, and wherein the conversion circuit further comprises a fourth inductor, one end of the fourth inductor is connected to the fourth bridge leg, and the other end of the fourth inductor is connected between the first capacitor and the second capacitor.

6. The conversion circuit according to any one of claims 1 to 5, further comprising a third switch connected between the neutral interface and the first capacitor, the third switch being adapted to be turned on when processing single-phase power and turned off when processing three-phase power.

7. The conversion circuit according to any one of claims 1 to 6, further comprising a fourth switch, a fifth switch, and first, second, third, fourth, fifth, and sixth diodes;

one end of the fourth switch is connected with the cathode of the first diode, the cathode of the second diode and the cathode of the third diode respectively, and the other end of the fourth switch is connected with the high-potential end of the direct-current port;

the anode of the first diode is connected with the cathode of the fourth diode, the anode of the second diode is connected with the cathode of the fifth diode, and the anode of the third diode is connected with the cathode of the sixth diode;

one end of the fifth switch is connected with the anode of the fourth diode, the anode of the fifth diode and the anode of the sixth diode respectively, and the other end of the fourth switch is connected with the low-potential end of the direct-current port;

the fourth switch and the fifth switch are both used for being switched on when single-phase power or three-phase power is converted into direct current, and switched off when the direct current is converted into the single-phase power or the three-phase power.

8. The conversion circuit according to any one of claims 1 to 7, wherein the first bridge arm comprises a first switching tube and a second switching tube which are connected in series, the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series, and the third bridge arm comprises a fifth switching tube and a sixth switching tube which are connected in series;

the first electrode of the first switching tube, the first electrode of the third switching tube and the first electrode of the fifth switching tube are connected with the high-potential end of the direct-current port;

the second electrode of the first switching tube is connected with the first electrode of the second switching tube, the second electrode of the third switching tube is connected with the first electrode of the fourth switching tube, and the second electrode of the fifth switching tube is connected with the first electrode of the sixth switching tube;

and the second electrode of the fourth switching tube, the second electrode of the fifth switching tube and the second electrode of the sixth switching tube are connected with the low-potential end of the direct-current port.

9. A converter, comprising: a conversion circuit and a controller;

the conversion circuit comprises a first interface, a second interface, a third interface, a zero line interface, a first bidirectional switch, a bridge type conversion circuit, a first capacitor and a second capacitor, wherein the bridge type conversion circuit comprises three bridge arms;

a first end of the first bidirectional switch is connected with a second bridge arm of the bridge type conversion circuit, a second end of the first bidirectional switch is connected with the first interface, a third end of the first bidirectional switch is connected with the second interface, and the second interface is used for connecting a second phase line;

one end of the first capacitor is connected with the high potential end of the direct current port, the other end of the first capacitor is connected with one end of the second capacitor, the other end of the second capacitor is connected with the low potential end of the direct current port, the zero line interface is connected between the first capacitor and the second capacitor, and the zero line interface is used for connecting a zero line;

the controller is configured to:

when single-phase electricity is processed, the first bidirectional switch is controlled to conduct connection between the second bridge arm and the first interface;

when three-phase electricity is processed, the first bidirectional switch is controlled to conduct connection between the second bridge arm and the second interface;

and controlling the bridge type conversion circuit to convert the single-phase power or the three-phase power into direct current and outputting the direct current from a direct current port of the conversion circuit, or receiving the direct current through the direct current port and converting the direct current into the single-phase power or the three-phase power.

10. The converter of claim 9, wherein the conversion circuit further comprises a first inductor, a second inductor, and a third inductor;

the first inductor is connected between the first interface and the first bridge arm, the second inductor is connected between the first bidirectional switch and the second bridge arm, and the third inductor is connected between the third interface and the third bridge arm.

11. The converter according to claim 10, wherein the conversion circuit further comprises a second bidirectional switch, a first end of the second bidirectional switch is connected to an end of the third inductor remote from the third leg, a second end of the second bidirectional switch is connected to the third interface, and a third end of the second bidirectional switch is connected to the neutral interface;

the controller is further configured to:

when single-phase electricity is processed, the second bidirectional switch is controlled to conduct connection between the third inductor and the zero line interface;

and controlling the second bidirectional switch to conduct the connection between the third interface and the zero line interface when three-phase power is processed.

12. The converter of claim 11, further comprising a detection circuit for detecting a voltage of the first capacitor and a voltage of the second capacitor;

the controller is further configured to:

acquiring the voltage of the first capacitor and the voltage of the second capacitor;

when the voltage of the first capacitor is greater than that of the second capacitor, controlling the third bridge arm and the third inductor to reduce the voltage of the first capacitor and increase the voltage of the second capacitor;

and when the voltage of the first capacitor is smaller than that of the second capacitor, controlling the third bridge arm and the third inductor to increase the voltage of the first capacitor and reduce the voltage of the second capacitor.

13. The converter according to claim 12, wherein the third bridge arm comprises a fifth switching tube and a sixth switching tube, a first electrode of the fifth switching tube is connected to the high potential end of the dc port, a second electrode of the fifth switching tube is connected to the third inductor and the first electrode of the sixth switching tube, respectively, and a second electrode of the sixth switching tube is connected to the low potential end of the dc port;

the controller is specifically configured to:

when the voltage of the first capacitor is greater than the voltage of the second capacitor, the fifth switching tube is switched on, and the sixth switching tube is switched off, so that the third inductor is charged, and the voltage of the first capacitor is reduced;

and disconnecting the fifth switching tube and connecting the sixth switching tube to discharge the third inductor, so that the voltage of the second capacitor is increased.

14. The converter according to claim 13, wherein the controller is specifically configured to:

when the voltage of the first capacitor is smaller than the voltage of the second capacitor, the sixth switching tube is switched on, and the fifth switching tube is switched off, so that the third inductor is charged, and the voltage of the second capacitor is reduced;

and disconnecting the sixth switching tube and connecting the fifth switching tube to discharge the third inductor, so that the voltage of the first capacitor is increased.

15. The converter according to claim 10, wherein the conversion circuit further comprises a third bidirectional switch, a first terminal of the third bidirectional switch is connected to a terminal of the third inductor remote from the third leg, a second terminal of the third bidirectional switch is connected to the first terminal of the first bidirectional switch, and a third terminal of the third bidirectional switch is connected to the third interface;

the controller is configured to:

turning on a connection between a first terminal of the first bidirectional switch and the third inductor when processing single-phase power;

and conducting the connection between the third interface and the third inductor when processing three-phase power.

16. The converter of claim 15, wherein the bridge conversion circuit further comprises a fourth leg, the conversion circuit further comprises a fourth inductor, one end of the fourth inductor is connected to the fourth leg, and the other end of the fourth inductor is connected between the first capacitor and the second capacitor;

the converter further comprises a detection circuit for detecting the voltage of the first capacitor and the voltage of the second capacitor;

the controller is further configured to:

when the voltage of the first capacitor is greater than that of the second capacitor, controlling the fourth bridge arm and the fourth inductor to reduce the voltage of the first capacitor and increase the voltage of the second capacitor;

and when the voltage of the first capacitor is smaller than that of the second capacitor, controlling the fourth bridge arm and the fourth inductor to increase the voltage of the first capacitor and reduce the voltage of the second capacitor.

17. The converter according to claim 16, wherein the fourth bridge arm comprises a seventh switching tube and an eighth switching tube, a first electrode of the seventh switching tube is connected to the high potential end of the dc port, a second electrode of the seventh switching tube is respectively connected to the fourth inductor and the first electrode of the eighth switching tube, and a second electrode of the eighth switching tube is connected to the low potential end of the dc port;

the controller is specifically configured to:

when the voltage of the first capacitor is greater than the voltage of the second capacitor, turning on the seventh switching tube, and turning off the eighth switching tube, so that the fourth inductor is charged, and the voltage of the first capacitor is reduced;

and switching off the seventh switching tube and switching on the eighth switching tube to discharge the fourth inductor, so that the voltage of the second capacitor is increased.

18. The converter according to claim 16 or 17, wherein the controller is specifically configured to:

when the voltage of the first capacitor is smaller than the voltage of the second capacitor, turning on the eighth switching tube, and turning off the seventh switching tube, so that the fourth inductor is charged, and the voltage of the second capacitor is reduced;

and the eighth switching tube is turned off, and the seventh switching tube is turned on, so that the fourth inductor discharges, and the voltage of the first capacitor rises.

19. The converter according to any of claims 9 to 18, wherein the conversion circuit further comprises a third switch connected between the neutral interface and the first capacitor;

the controller is further configured to:

the third switch is turned on when single-phase power is processed and turned off when three-phase power is processed.

20. The converter according to any one of claims 9 to 19, wherein the conversion circuit further comprises a fourth switch, a fifth switch, and a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode;

the controller is further configured to:

turning on the fourth switch and the fifth switch when the single-phase or three-phase power is converted into direct current;

the fourth switch and the fifth switch are turned off when the direct current is converted into single-phase power or three-phase power.

21. An electronic device, characterized in that it comprises a converter according to any one of claims 9 to 20.