阅读说明：本技术 一种多脉波整流电路以及充电装置 (Multi-pulse-wave rectifying circuit and charging device ) 是由 刘卫平 张维 顾师达 于 2021-07-27 设计创作，主要内容包括：本申请提供了一种多脉波整流电路以及充电装置,该多脉波整流电路设于交流电网与用电设备之间,包括第一变压单元和第二变压单元；其中该第一变压单元包括第一移相变压器、第一整流桥和第二整流桥,该第一移相变压器包括一个原边绕组、第一副边绕组以及第二副边绕组,第一移相变压器的原边绕组与第二变压单元的输入端串联耦合后的两端与交流电网耦合；第一移相变压器的第一副边绕组与第一整流桥的输入端耦合,第一移相变压器的第二副边绕组与第二整流桥的输入端耦合,第一整流桥的输出端与第二整流桥的输出端串联耦合后的两端与用电设备耦合,且用电设备还耦合第二变压单元的输出端。实施本申请,提高整流效率并可以减小变压器的使用数量。(The application provides a multi-pulse-wave rectifying circuit and a charging device, wherein the multi-pulse-wave rectifying circuit is arranged between an alternating current power grid and electric equipment and comprises a first voltage transformation unit and a second voltage transformation unit; the first transformation unit comprises a first phase-shifting transformer, a first rectifier bridge and a second rectifier bridge, the first phase-shifting transformer comprises a primary winding, a first secondary winding and a second secondary winding, and two ends of the primary winding of the first phase-shifting transformer and two ends of the input end of the second transformation unit after being coupled in series are coupled with an alternating current power grid; the first secondary winding of the first phase-shifting transformer is coupled with the input end of the first rectifier bridge, the second secondary winding of the first phase-shifting transformer is coupled with the input end of the second rectifier bridge, the two ends of the output end of the first rectifier bridge and the output end of the second rectifier bridge after being coupled in series are coupled with electric equipment, and the electric equipment is further coupled with the output end of the second transformation unit. By implementing the method and the device, the rectification efficiency is improved, and the using number of the transformers can be reduced.)

1. A multi-pulse wave rectification circuit is characterized in that the multi-pulse wave rectification circuit is arranged between an alternating current power grid and electric equipment and comprises a first voltage transformation unit and a second voltage transformation unit, wherein the first voltage transformation unit comprises a first phase-shifting transformer, a first rectification bridge and a second rectification bridge, and the first phase-shifting transformer comprises a primary winding, a first secondary winding and a second secondary winding;

the two ends of the primary winding of the first phase-shifting transformer and the input end of the second transformation unit which are coupled in series are coupled with the alternating current power grid;

the first secondary winding of the first phase-shifting transformer is coupled with the input end of the first rectifier bridge, the second secondary winding of the first phase-shifting transformer is coupled with the input end of the second rectifier bridge, the output end of the first rectifier bridge and the output end of the second rectifier bridge are coupled with the electric equipment at two ends after being coupled in series, and the electric equipment is further coupled with the output end of the second voltage transformation unit.

2. The multi-pulse rectification circuit according to claim 1, wherein a phase difference between an output voltage of a first secondary winding of the first phase-shifting transformer and an output voltage of a second secondary winding of the first phase-shifting transformer is determined in accordance with the number of secondary windings included in the first phase-shifting transformer.

3. The multi-pulse rectification circuit according to any one of claims 1 to 2, wherein a phase difference between an output voltage of a first secondary winding of the first phase-shifting transformer and an output voltage of a second secondary winding of the first phase-shifting transformer is pi/(3), where n is the number of secondary windings included in the first phase-shifting transformer.

4. The multi-pulse rectifier circuit of claim 3, wherein n is an integer greater than 2; the first secondary winding of the first phase-shifting transformer and the second secondary winding of the first phase-shifting transformer are any two secondary windings of n secondary windings included in the first phase-shifting transformer.

5. The multi-pulse rectification circuit according to any one of claims 2-4, wherein the second transforming unit comprises a second phase-shifting transformer, a third rectification bridge and a fourth rectification bridge, the second phase-shifting transformer comprises a primary winding, a first secondary winding and a second secondary winding; wherein the content of the first and second substances,

the two ends of the primary winding of the second phase-shifting transformer and the primary winding of the first phase-shifting transformer after being coupled in series are coupled with the alternating current power grid;

and a first secondary winding of the second phase-shifting transformer is coupled with the input end of the third rectifier bridge, a second secondary winding of the second phase-shifting transformer is coupled with the input end of the fourth rectifier bridge, and the two ends of the output end of the third rectifier bridge and the output end of the fourth rectifier bridge after being coupled in series are coupled with the electric equipment.

6. The multi-pulse rectification circuit according to claim 5, wherein a phase difference between an output voltage of the first secondary winding of the second phase-shifting transformer and an output voltage of the first secondary winding of the first phase-shifting transformer is a first angle, and a phase difference between an output voltage of the second secondary winding of the second phase-shifting transformer and an output voltage of the second secondary winding of the first phase-shifting transformer is also the first angle.

7. The multi-pulse rectification circuit according to claim 6, wherein the first angle is determined according to the number of secondary windings included in the first phase-shift transformer, the number of secondary windings included in the second phase-shift transformer, and the number of voltage transformation units included in the multi-pulse rectification circuit.

8. The multi-pulse rectification circuit according to claim 7, wherein the first angle is pi/(3), wherein the number of secondary windings included in the second phase-shifting transformer and the number of secondary windings included in the first phase-shifting transformer are both n, and m is the number of voltage transformation units included in the multi-pulse rectification circuit.

9. The multi-pulse rectification circuit according to claim 8, wherein the phase angles of the output voltages of the respective secondary windings included in the first phase-shifting transformer are-25 °, 5 °, and 15 °, respectively, and the phase angles of the output voltages of the respective secondary windings included in the second phase-shifting transformer are-15 °, 5 °, and 25 °, respectively.

10. A charging device comprising the multi-pulse rectifier circuit and the DC/DC converter according to any one of claims 1 to 9; wherein the content of the first and second substances,

the multi-pulse wave rectifying circuit is used for rectifying alternating current into first direct current and transmitting the first direct current to the DC/DC converter; the DC/DC converter is used for converting the voltage of the first direct current to obtain a second direct current and transmitting the second direct current to electric equipment.

11. The charging apparatus of claim 10, wherein the powered device comprises at least one electric vehicle;

the charging device also comprises a power distribution cabinet, and the power distribution cabinet is arranged between the multi-pulse wave rectifying circuit and the DC/DC converter; the power distribution cabinet is used for controlling the output power of the multi-pulse rectification circuit to the at least one electric automobile.

Technical Field

The application relates to the technical field of power supply, in particular to a multi-pulse rectification circuit and a charging device.

Background

With the development of power electronic technology, more and more electric devices are connected to an alternating current power grid, and the electric devices can cause certain harmonic pollution to the alternating current power grid and influence the power supply quality of the alternating current power grid.

In order to reduce the harmonic pollution of the electric equipment to the alternating current power grid, the national power grid respectively stipulates the harmonic distortion rate (THD) limit values of different electric equipment accessed to the alternating current power grid. In order to meet the THD limit requirements specified by the national grid, in a location such as a high voltage dc charging station, multi-pulse rectification is generally performed by using a phase-shifting transformer and a rectifier bridge as shown in fig. 1. As shown in fig. 1, in the prior art, output ends of all rectifier bridges are connected in series and then connected to an electric device, so that output voltages of the rectifier bridges connected in series are superposed through voltage drops of all rectifier bridges, and the number of pulse waves needs to be increased by increasing the number of phase-shifting transformers.

Disclosure of Invention

The application provides a many pulse wave rectifier circuit and charging device can improve rectification efficiency to can reduce the use quantity of transformer.

In a first aspect, an embodiment of the present application provides a multi-pulse rectification circuit, where the multi-pulse rectification circuit is disposed between an ac power grid and an electric device, and the multi-pulse rectification circuit includes a first voltage transformation unit and a second voltage transformation unit, where the first voltage transformation unit includes a first phase-shifting transformer, a first rectification bridge, and a second rectification bridge, and the first phase-shifting transformer includes a primary winding, a first secondary winding, and a second secondary winding. In a specific implementation, two ends of a primary winding of the first phase-shifting transformer and an input end of the second transformation unit which are coupled in series are coupled with the alternating-current power grid; the first secondary winding of the first phase-shifting transformer is coupled with the input end of the first rectifier bridge, the second secondary winding of the first phase-shifting transformer is coupled with the input end of the second rectifier bridge, the two ends of the output end of the first rectifier bridge and the output end of the second rectifier bridge after being coupled in series are coupled with the electric equipment, and the electric equipment is further coupled with the output end of the second transformation unit. This application embodiment is through dividing into two at least vary voltage units with many pulse wave rectifier circuits, and the connected mode between the output of vary voltage unit has been changed, the output of each rectifier bridge in the first vary voltage unit is established ties promptly, but connect in parallel between the output of each vary voltage unit, make the electric current that each vary voltage unit output to consumer only pass through the diode of rectifier bridge in the first vary voltage unit or only pass through second vary voltage unit, but not all rectifier bridges in the many pulse wave rectifier circuits, the voltage loss of the unit output to consumer of varying voltage has been reduced, rectification efficiency has been improved. And the primary winding of the first phase-shifting transformer is coupled with the input end of the second transformation unit in series, and the currents in the series branches are equal everywhere, so that the input ends of the multi-pulse-wave rectification circuit can equalize the current, and the loss between the input ends of the multi-pulse-wave rectification circuit can be reduced. In addition, in the embodiment of the present application, the first transforming unit may increase the number of pulses by only increasing the number of the secondary windings of the first phase-shifting transformer, so as to achieve the effect of increasing the rectification of the phase-shifting transformer in the prior art, that is, a plurality of secondary windings may share one primary winding, and at this time, the embodiment of the present application is also specifically presented as a transformer, and the number of transformers is reduced.

With reference to the first aspect, in a first possible implementation manner, a phase difference between an output voltage of the first secondary winding of the first phase-shifting transformer and an output voltage of the second secondary winding of the first phase-shifting transformer is determined according to the number of secondary windings included in the first phase-shifting transformer.

With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner, a phase difference between an output voltage of the first secondary winding of the first phase-shifting transformer and an output voltage of the second secondary winding of the first phase-shifting transformer is specifically pi/(3), where n is the number of secondary windings included in the first phase-shifting transformer.

With reference to the second possible implementation manner of the first aspect, in a third possible implementation manner, n is an integer greater than 2; the first secondary winding of the first phase-shifting transformer and the second secondary winding of the first phase-shifting transformer are any two secondary windings among the n secondary windings included in the first phase-shifting transformer. In other words, the first transforming unit in the embodiment of the present application may include a plurality of secondary windings, and the phase difference between the output voltages of two adjacent secondary windings having a connection relationship is pi/(3).

With reference to any one of the foregoing possible implementation manners of the first aspect, in a fourth possible implementation manner, the second transforming unit includes a second phase-shifting transformer, a third rectifier bridge, and a fourth rectifier bridge, where the second phase-shifting transformer includes a primary winding, a first secondary winding, and a second secondary winding; wherein, two ends of the primary winding of the second phase-shifting transformer after being coupled with the primary winding of the first phase-shifting transformer in series are coupled with the AC power grid; the first secondary winding of the second phase-shifting transformer is coupled with the input end of the third rectifier bridge, the second secondary winding of the second phase-shifting transformer is coupled with the input end of the fourth rectifier bridge, and the two ends of the output end of the third rectifier bridge, which are coupled in series with the output end of the fourth rectifier bridge, are coupled with the electric equipment.

With reference to the fourth possible implementation manner of the first aspect, in a fifth possible implementation manner, a phase difference between an output voltage of the first secondary winding of the second phase-shifting transformer and an output voltage of the first secondary winding of the first phase-shifting transformer is a first angle, and a phase difference between an output voltage of the second secondary winding of the second phase-shifting transformer and an output voltage of the second secondary winding of the first phase-shifting transformer is also the first angle. In other words, a phase difference between the output voltage of the first secondary winding of the second phase-shifting transformer and the output voltage of the first secondary winding of the first phase-shifting transformer is equal to a phase difference between the output voltage of the second secondary winding of the second phase-shifting transformer and the output voltage of the second secondary winding of the first phase-shifting transformer.

With reference to the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner, the first angle is determined according to the number of secondary windings included in the first phase-shifting transformer, the number of secondary windings included in the second phase-shifting transformer, and the number of transforming units included in the multi-pulse rectification circuit.

With reference to the sixth possible implementation manner of the first aspect, in a seventh possible implementation manner, the first angle is pi/(3), where the number of secondary windings included in the second phase-shifting transformer and the number of secondary windings included in the first phase-shifting transformer are both n, and m is the number of voltage transformation units included in the multi-pulse rectification circuit.

With reference to the sixth possible implementation manner of the first aspect, in an eighth possible implementation manner, the phase angles of the output voltages of the secondary windings included in the first phase-shifting transformer are-25 °, 5 °, and 15 °, respectively, and the phase angles of the output voltages of the secondary windings included in the second phase-shifting transformer are-15 °, 5 °, and 25 °, respectively. In the embodiment of the present application, the phase angles of the secondary windings included in the first phase-shifting transformer and the phase angles of the secondary windings included in the second phase-shifting transformer are opposite numbers, and at this time, the first phase-shifting transformer and the second phase-shifting transformer can be considered to be symmetrical, that is, the windings of the first phase-shifting transformer and the second phase-shifting transformer can be the same, the processing technology can be the same, and the production is facilitated.

In a second aspect, embodiments of the present application provide a charging apparatus, which includes a multi-pulse rectification circuit and a DC/DC converter as in combination with the first aspect or in combination with any one of the possible implementations of the first aspect. The multi-pulse rectification circuit can rectify the alternating current into a first direct current and transmit the first direct current to the DC/DC converter; the DC/DC converter may convert a voltage of the first direct current to obtain a second direct current, and transmit the second direct current to an electric device.

With reference to the first possible implementation manner of the second aspect, in a first possible implementation manner, the electrical device includes at least one electric vehicle, the charging apparatus may further include a power distribution cabinet, the power distribution cabinet is disposed between the multi-pulse rectification circuit and the DC/DC converter, and the power distribution cabinet may control output power of the multi-pulse rectification circuit to the at least one electric vehicle.

It should be understood that the implementations and advantages of the various aspects described above in this application may be referenced to one another.

Drawings

FIG. 1 is a block diagram of a multi-pulse rectifier circuit in the prior art;

fig. 2A is a block diagram of a charging device according to an embodiment of the present disclosure;

fig. 2B is a system architecture diagram of a charging device for an electric vehicle according to an embodiment of the present disclosure;

fig. 3 is a block diagram of a multi-pulse rectifier circuit according to an embodiment of the present disclosure;

fig. 4 is a block diagram of another structure of a multi-pulse rectifier circuit according to an embodiment of the present disclosure;

fig. 5 is a block diagram of another structure of a multi-pulse rectifier circuit according to an embodiment of the present disclosure;

fig. 6 is a block diagram of another structure of a multi-pulse rectifier circuit according to an embodiment of the present disclosure;

fig. 7 is a block diagram of another structure of a multi-pulse rectifier circuit according to an embodiment of the present application;

fig. 8A is a schematic waveform diagram of a three-phase input voltage and a three-phase output voltage provided by an embodiment of the present application;

fig. 8B is a schematic waveform diagram of a three-phase input current and a three-phase output current provided by the embodiment of the present application;

fig. 9 is a simulation diagram of fast fourier transform analysis provided in the embodiment of the present application.

Detailed Description

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, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The following describes embodiments of the present application in further detail with reference to the accompanying drawings.

Referring to fig. 2A, fig. 2A is a block diagram of a charging device according to an embodiment of the present disclosure. As shown in fig. 2A, the charging device 21 is provided between an ac power source (e.g., an ac power grid) and the electric equipment. The charging device 21 may include a multi-pulse rectification circuit 211 and a DC/DC converter 212. The input end of the multi-pulse wave rectifying circuit 211 is coupled to an alternating current power supply (for example, an alternating current power grid), the output end of the multi-pulse wave rectifying circuit 211 is coupled to the input end of the DC/DC converter 212, and the output end of the DC/DC converter 212 is coupled to the electric equipment.

It is noted that, as used herein, the term "coupled" means directly or indirectly connected. For example, a and B are coupled, and may be directly connected, or indirectly connected through one or more other electrical components, for example, a and C are directly connected, and C and B are directly connected, so that a and B are connected through C.

The multi-pulse rectification circuit 211 can rectify the alternating current to obtain a first direct current, and can transmit the first direct current to the DC/DC converter 212. The DC/DC converter 212 may convert the voltage of the first direct current to obtain a second direct current, and may transmit the second direct current to an electric device.

For example, the electric device may be a terminal, an inverter, an electric vehicle, or the like.

Illustratively, the DC/DC converter 212 may be, for example, a BUCK converter, which may step down the first direct current to obtain a second direct current, i.e., the second direct current may be smaller than the first direct current. The DC/DC converter 212 may be, for example, a BOOST converter, which may BOOST the first direct current to obtain a second direct current, i.e., the second direct current may be greater than the first direct current. Optionally, the DC/DC converter 212 may also be, for example, a BUCK-BOOST converter, which may BOOST or BUCK the first direct current to obtain a second direct current, i.e., the second direct current may be greater than or less than the first direct current. Alternatively, the DC/DC converter 212 may be built into the charging post of the charging station, in particular in the form of a printed circuit board PCB.

In some possible embodiments, referring to fig. 2B, fig. 2B is a block diagram of a system architecture of a charging device for an electric vehicle according to an embodiment of the present disclosure. As shown in fig. 2B, taking an example that the electric device includes at least one electric vehicle, in order to be applicable to an application scenario where a charging station charges a plurality of electric vehicles at the same time, the charging apparatus provided in the embodiment of the present application may further include a power distribution cabinet 22, where the power distribution cabinet 22 may be disposed between the multi-pulse rectification circuit and the DC/DC converter (e.g., the DC/DC converter 2121 and the DC/DC converter 2122) to control the output power of the multi-pulse rectification circuit to the at least one electric vehicle. In some possible embodiments, a controller is provided in the distribution cabinet 22, and the controller can monitor the insertion state of the charging pile (i.e. the connection condition of the electric vehicles with the respective DC/DC converters) and the remaining capacity of each electric vehicle connected with the DC/DC converters. For example, the controller may control the power distribution cabinet 22 to provide all the power output by the multi-pulse rectification circuit to the electric vehicle 1 if it is not detected that the other DC/DC converter (e.g., the DC/DC converter 2122) is connected to the electric vehicle 2 at this time. If the controller detects that the electric vehicle 2 is connected to the DC/DC converter 2122 during charging of the electric vehicle 1, and the remaining power of the electric vehicle 2 is 30%, that is, it is determined that the electric vehicle 2 needs to be charged, at this time, the controller may control the power distribution cabinet 22 to equally distribute the power output by the multi-pulse rectification circuit to the DC/DC converter 2121 and the DC/DC converter 2122. As a further alternative, the controller may prioritize the DC/DC converters, e.g., DC/DC converter 2121 takes priority over DC/DC converter 2122, when the DC/DC converter 2121 is connected to the electric vehicle 1, and the controller detects that the DC/DC converter 2122 is connected to the electric vehicle 2, the controller may control the power distribution cabinet 22 to perform gradient power transmission on the electric vehicle corresponding to each DC/DC converter according to the priority of each DC/DC converter, for example, the priority of the DC/DC converter 2121 is higher than that of the DC/DC converter 2122, the power output by the multi-pulse rectification circuit is 100W, and the controller may control the power distribution cabinet 22 to transmit 75W of power to the electric vehicle 1 corresponding to the DC/DC converter 2121 and transmit 25W of power to the electric vehicle 2 corresponding to the DC/DC converter 2122. It can be understood that the power distribution cabinet is only exemplarily described herein, but not exhaustive, and it should be understood that the power distribution cabinet may also have other implementation manners, and specifically refer to the implementation of the power distribution cabinet in the prior art, which is not described herein in detail.

The following describes a specific structure of a multi-pulse rectifier circuit according to an embodiment of the present application with reference to the drawings.

Referring to fig. 3, fig. 3 is a block diagram of a multi-pulse rectifier circuit according to an embodiment of the present disclosure. As shown in fig. 3, the multi-pulse wave rectification circuit 32 is disposed between the ac power grid and the electric equipment, that is, the input end of the multi-pulse wave rectification circuit 32 is coupled to the ac power grid, and the output end of the multi-pulse wave rectification circuit 32 is coupled to the electric equipment.

It should be noted that, for simplicity, the three oblique lines on the connection line represent that the connection line actually represents three wires to transmit three-phase voltages and three-phase currents.

In some possible embodiments, the multi-pulse rectification circuit 32 includes a first transforming unit 321 and a second transforming unit 322. The first transforming unit 321 includes a first phase shifting transformer 3210, a first rectifier bridge 3211, and a second rectifier bridge 3212. The first phase-shifting transformer 3210 may include a primary winding T1, a first secondary winding T₁₁And a second secondary winding t₁₂。

Two ends of a primary winding T1 of the first phase-shifting transformer 3210 and the input end of the second transformation unit 322 after being coupled in series are coupled with an alternating current grid, and a first secondary winding T of the first phase-shifting transformer 3210₁₁A second secondary winding t of the first phase-shifting transformer 3210 coupled to an input terminal of the first rectifier bridge 3211₁₂The output end of the first rectifier bridge 3211 is coupled to the output end of the second rectifier bridge 3212, and both ends of the output end of the first rectifier bridge 3211 and the output end of the second rectifier bridge 3212 after being coupled in series are coupled to an electrical device, and the electrical device is further coupled to the output end of the second transforming unit 322.

It can be understood that the rectifier bridge related in the embodiment of the present application may be a diode full-bridge rectifier or a diode half-bridge rectifier in the prior art, and specific implementation may refer to the prior art, which is not described herein.

In the embodiment of the present application, the output terminal of the first transforming unit and the output terminal of the second transforming unit in the multi-pulse rectification circuit are connected in parallel to the electrical equipment, and compared with the prior art in which the output terminals of all the rectification bridges are coupled in series to the electrical equipment, the embodiment of the present application divides the multi-pulse rectification circuit into at least two transforming units and changes the connection manner between the output terminals of the transforming units, namely, the output ends of all the rectifier bridges in the first voltage transformation unit are connected in series, but the output ends of all the voltage transformation units are connected in parallel, so that the current output by each transformation unit to the electric equipment only passes through the diode of the rectifier bridge in the first transformation unit or only passes through the second transformation unit, instead of all rectifier bridges in the multi-pulse rectifier circuit, the voltage loss of the voltage transformation unit output to the electric equipment is reduced, and the rectification efficiency is improved. And the primary winding of the first phase-shifting transformer is coupled with the input end of the second transformation unit in series, and the currents in the series branches are equal everywhere, so that the input ends of the multi-pulse-wave rectification circuit can be equalized, and the loss between the input ends of the multi-pulse-wave rectification circuit can be further reduced. In addition, in the embodiment of the present application, the first transforming unit may increase the number of pulses by only increasing the number of the secondary windings of the first phase-shifting transformer, so as to achieve the effect of increasing the rectification of the phase-shifting transformer in the prior art, that is, a plurality of secondary windings may share one primary winding, and at this time, the embodiment of the present application is also specifically presented as a transformer, and the number of transformers is reduced.

In some possible embodiments, the second transforming unit 322 may be a power factor correction circuit in the prior art. Optionally, the second transforming unit may further have a topology similar to that of the first transforming unit 321, for example, see fig. 4, and fig. 4 is a further structural block diagram of the multi-pulse rectification circuit provided in the embodiment of the present application. As shown in fig. 4, the second transforming unit 322 comprises a second phase-shifting transformer 3220, a third rectifying bridge 3221 and a fourth rectifying bridge 3222, wherein the second phase-shifting transformer 3220 comprises a primary winding T2, a first secondary winding T₂₁And a second secondary winding t₂₂. The input end of the second transforming unit 322 is the primary winding T2 of the second phase-shifting transformer 3220, that is, the coupling between the two ends of the primary winding T1 of the first phase-shifting transformer and the input end of the second transforming unit 322 after being coupled in series and the ac power grid is specifically realized as follows: the primary winding T2 of the second phase-shifting transformer 3220 is coupled in series with the primary winding T1 of the first phase-shifting transformer 3210, and both ends of the coupled primary winding are coupled to the ac power grid. First secondary winding t of second phase-shifting transformer 3220₂₁A second secondary winding t of a second phase-shifting transformer 3220 coupled to an input of a third rectifier bridge 3221₂₂Coupled to an input of a fourth rectifier bridge 3222. The output end of the second voltage transformation unit 322 is the two ends of the third rectifier bridge 3221 and the fourth rectifier bridge 3222 coupled in series, that is, the output end of the second voltage transformation unit 322 coupled by the electrical device is specifically implemented as follows: two ends and use ends of the output end of the third rectifying bridge 3221 and the output end of the fourth rectifying bridge 3222 which are coupled in seriesThe electrical devices are coupled.

Optionally, in some possible implementations, referring to fig. 5, fig. 5 is a block diagram of another structure of the multi-pulse rectifier circuit provided in the embodiment of the present application. As shown in fig. 5, the first transforming unit in the embodiment of the present application may include a first phase-shifting transformer and n rectifying bridges, and the second transforming unit may include a second phase-shifting transformer and k rectifying bridges. The first phase-shifting transformer comprises a primary winding T1 and n secondary windings, wherein n is an integer greater than 2; the second phase shifting transformer may include a primary winding T2 and k secondary windings, where k is an integer greater than 1.

In a specific implementation, each secondary winding of the first phase-shifting transformer is coupled to an input terminal of a corresponding rectifier bridge, for example, the first secondary winding t of the first phase-shifting transformer₁₁A second secondary winding t of the first phase-shifting transformer coupled to the input of the first rectifier bridge₁₂An nth secondary winding t of the first phase-shifting transformer coupled to the input of the second rectifier bridge_1nCoupled to an input of the nth rectifier bridge. The output ends of the first rectifier bridge and the nth rectifier bridge are sequentially coupled in series, for example, the output end of the first rectifier bridge is connected with the output end of the second rectifier bridge in series, the output end of the second rectifier bridge is connected with the output end of the third rectifier bridge in series, and so on, the output end of the (n-1) th rectifier bridge is connected with the output end of the nth rectifier bridge in series. The phase difference of the output voltages of the two secondary windings correspondingly coupled with the two adjacent rectifier bridges is determined according to the number of the secondary windings included in the first phase-shifting transformer, and can be represented as pi/(3). Taking the example of the first phase-shifting transformer shown in fig. 3 or 4 comprising two secondary windings (i.e. n-2), the first secondary winding t of the first phase-shifting transformer₁₁And the second secondary winding t of the first phase-shifting transformer₁₂The phase difference between the output voltages of (1) is 30 deg..

Similarly, the secondary windings of the second phase-shifting transformer are also coupled to the input of the respective rectifier bridge, for example the first secondary winding t of the second phase-shifting transformer₂₁A kth secondary side of the second phase-shifting transformer coupled to the input terminal of the (n + 1) th rectifier bridgeWinding t_2kCoupled to the input of the (n + k) th rectifier bridge. The output ends of the n +1 th rectifier bridge and the n + k th rectifier bridge are sequentially coupled in series, for example, the output end of the n +1 th rectifier bridge is connected with the output end of the n +2 th rectifier bridge in series, the output end of the n +2 th rectifier bridge is connected with the output end of the n +3 th rectifier bridge in series, and so on, the output end of the n + k-1 th rectifier bridge is connected with the output end of the n + k th rectifier bridge in series. The phase difference of the output voltages of the two secondary windings correspondingly coupled with the two adjacent rectifier bridges is determined according to the number of the secondary windings included in the second phase-shifting transformer, and can be represented as pi/(3). Taking the example of the second phase-shifting transformer shown in fig. 4 comprising two secondary windings (i.e. k 2), the first secondary winding t of the second phase-shifting transformer₂₁And the second secondary winding t of the second phase-shifting transformer₂₂The phase difference between the output voltages of (1) is 30 deg..

The output voltages of the secondary windings of the two phase-shifting transformers have a corresponding relationship. For example, the first secondary winding t of the second phase-shifting transformer₂₁And the first secondary winding t of the first phase-shifting transformer₁₁The phase difference between the output voltages of the first and second phase-shifting transformers is a first angle, and a second secondary winding t of the second phase-shifting transformer₂₂And the second secondary winding t of the first phase-shifting transformer₁₂Is also the first angle. In other words, the first secondary winding t of the second phase-shifting transformer₂₁And the first secondary winding t of the first phase-shifting transformer₁₁Is equal to the second secondary winding t of the second phase-shifting transformer₂₂And the second secondary winding t of the first phase-shifting transformer₁₂The phase difference between the output voltages of (a).

The first angle is determined according to the number of secondary windings of the first phase-shifting transformer, the number of secondary windings of the second phase-shifting transformer and the number of transformation units contained in the multi-pulse rectification circuit.

For example, the number of secondary windings included in the first phase-shifting transformer is equal to the number of secondary windings included in the second phase-shifting transformer, i.e., k ═ n. Then the above mentionedThe first angle may be expressed as: and pi/(3), wherein the number of secondary windings contained in the second phase-shifting transformer and the number of secondary windings contained in the first phase-shifting transformer are both n, and m is the number of transformation units contained in the multi-pulse rectification circuit. Taking the multi-pulse rectification circuit shown in fig. 4 including the first transforming unit and the second transforming unit (i.e., m is 2), and the number of secondary windings included in each phase-shifting transformer is 2 (i.e., n is 2), the first angle is 15 °. In other words, the first secondary winding t of the second phase-shifting transformer₂₁And the first secondary winding t of the first phase-shifting transformer₁₁Is 15 deg., and a second secondary winding t of a second phase shifting transformer₂₂And the second secondary winding t of the first phase-shifting transformer₁₂Is also 15 deg..

For another example, the number of the secondary windings included in the first phase-shifting transformer is different from the number of the secondary windings included in the second phase-shifting transformer, and the description thereof is omitted here.

The embodiments described above in connection with fig. 4 and 5 may be understood as different implementations of the present application, for example, the topology of the second transforming unit may be similar to the topology of the first transforming unit, and each phase shifting transformer may have a plurality of equal or unequal numbers of secondary windings.

Further, in some possible embodiments, the present application may further have a plurality of voltage transformation units. Referring to fig. 6, fig. 6 is a block diagram of another structure of the multi-pulse rectifier circuit according to the embodiment of the present application. As shown in fig. 6, the multi-pulse rectification circuit provided in the embodiment of the present application includes m voltage transformation units. The first transforming unit may include a first phase-shifting transformer and n rectifier bridges, the second transforming unit may include a second phase-shifting transformer and k rectifier bridges, the mth transforming unit may include an mth phase-shifting transformer and r rectifier bridges, and r is a positive integer.

In the first transformation unit, the first phase-shifting transformer includes a primary winding T1 and n secondary windings. In a specific implementation, the first secondary winding t of the first phase-shifting transformer₁₁A second secondary winding t of the first phase-shifting transformer coupled to the input of the first rectifier bridge₁₂An nth secondary winding t of the first phase-shifting transformer coupled to the input of the second rectifier bridge_1nCoupled to an input of the nth rectifier bridge. The output ends of the first rectifier bridge and the nth rectifier bridge are sequentially coupled in series, for example, the output end of the first rectifier bridge is connected with the output end of the second rectifier bridge in series, the output end of the second rectifier bridge is connected with the output end of the third rectifier bridge in series, and so on, the output end of the (n-1) th rectifier bridge is connected with the output end of the nth rectifier bridge in series. And both ends of each rectifier bridge in the first voltage transformation unit after being coupled in series are coupled with the electric equipment.

Similarly, in the second transforming unit, the second phase-shifting transformer may include one primary winding T2 and k secondary windings. In a specific implementation, the first secondary winding t of the second phase-shifting transformer₂₁A kth secondary winding t of the second phase-shifting transformer coupled to the input terminal of the (n + 1) th rectifier bridge_2kCoupled to the input of the (n + k) th rectifier bridge. The output ends of the n +1 th rectifier bridge and the n + k th rectifier bridge are sequentially coupled in series, for example, the output end of the n +1 th rectifier bridge is connected with the output end of the n +2 th rectifier bridge in series, the output end of the n +2 th rectifier bridge is connected with the output end of the n +3 th rectifier bridge in series, and so on, the output end of the n + k-1 th rectifier bridge is connected with the output end of the n + k th rectifier bridge in series. And both ends of each rectifier bridge in the second voltage transformation unit after being coupled in series are coupled with the electric equipment.

By analogy, in the mth transformation unit, the mth phase-shifting transformer may include one primary winding Tm and r secondary windings. In specific implementation, the first secondary winding t of the mth phase-shifting transformer_m1And the input end of the (i + 1) th rectifier bridge is coupled, wherein i is the number of the rectifier bridges included in the first voltage transformation unit to the (m-1) th voltage transformation unit plus 1. The r secondary winding t of the second phase-shifting transformer_mrCoupled to the input of the (i + r) th rectifier bridge. The output ends of the ith rectifier bridge and the (i + r) th rectifier bridge are sequentially coupled in series, for example, the output end of the ith rectifier bridge is connected with the output end of the (i + 1) th rectifier bridge in series, the output end of the (i + 2) th rectifier bridge is connected with the output end of the (i + 3) th rectifier bridge in series, and so on, and theThe output end of the i + r-1 rectifier bridge is connected with the output end of the i + r rectifier bridge in series. And both ends of each rectifier bridge in the mth voltage transformation unit after being coupled in series are coupled with the electric equipment.

It is understood that the phase difference of the output voltages of the secondary windings included in the respective phase-shifting transformers in the respective transforming units is related to the number of the secondary windings included in the respective phase-shifting transformers. For example, the phase difference of the output voltages of the secondary windings of the first phase-shifting transformer in the first transformation unit is pi/(3 n); the phase difference of the output voltage of each secondary winding of the second phase-shifting transformer in the second transformation unit is pi/(3 k); the phase difference of the output voltages of the secondary windings of the mth phase-shifting transformer in the mth transformation unit is pi/(3 r).

And the secondary windings contained in two adjacent phase-shifting transformers with the series connection relationship between the primary windings have corresponding relationship. It is assumed that the number of secondary windings included in each phase-shifting transformer is equal, i.e., n-k-r. The first secondary winding t of the first phase-shifting transformer₁₁And the output voltage of the first secondary winding t of the second phase-shifting transformer₂₁The phase difference between the output voltages of (2) is pi/(3 nm); nth secondary winding t of first phase-shifting transformer_1nAnd the kth secondary winding t of the second phase-shifting transformer_2kIs also pi/(3 nm). In the same way, the first secondary winding t of the mth phase-shifting transformer_m1And the first secondary winding t of the m-1 th phase-shifting transformer_(m-1)1Is also pi/(3 nm), and the mth secondary winding t of the mth phase-shifting transformer_mrAnd the output voltage of the (m-1) th secondary winding t of the phase-shifting transformer_(m-1)rIs also pi/(3 nm).

It is understood that the embodiment described above with reference to fig. 6 is still another possible implementation manner of the present application, and compared to the embodiment described above with reference to fig. 3 to 5, the embodiment of the present application may be configured with a plurality of transforming units, that is, the multi-pulse rectification circuit may include more than 2 transforming units, although the number of pulses may be increased by increasing the number of secondary windings of the phase-shifting transformer, when too many secondary windings are provided in one phase-shifting transformer, the volume of the phase-shifting transformer may be too large, and the loss caused thereby is also large, so the embodiment of the present application provides another possible implementation manner, and besides the number of secondary windings of the phase-shifting transformer may be increased, the number of transforming units may also be increased to increase the number of pulses.

In the research and practice process, the inventor of the present application finds that, in order to meet the national standard, the current THD is less than 4%, the multi-pulse wave rectification circuit may include two voltage transformation units and six rectification bridges as shown in fig. 7, each voltage transformation unit includes three secondary windings, and each rectification bridge outputs two pulse waves, that is, six pulse waves, of three-phase current in one period. Six secondary windings can achieve 36-pulse rectification. If 36-pulse rectification is realized according to the prior art as shown in fig. 1, 6 phase-shifting transformers need to be arranged, but only two phase-shifting transformers need to be arranged in the embodiment of the present application, so that the embodiment of the present application can achieve a good rectification effect by using a small number of phase-shifting transformers, and has high rectification efficiency.

In a specific implementation, two ends of the primary winding T1 of the first phase-shifting transformer and the primary winding T2 of the second phase-shifting transformer after being coupled in series are coupled with an alternating current grid. Three secondary windings of the first phase-shifting transformer are respectively coupled with the input ends of the rectifier bridges corresponding to the three secondary windings of the first phase-shifting transformer, and two ends of the three rectifiers corresponding to the three secondary windings of the first phase-shifting transformer after being sequentially coupled in series are coupled with electric equipment. Similarly, the three secondary windings of the second phase-shifting transformer are respectively coupled with the input ends of the rectifier bridges corresponding to the three secondary windings of the second phase-shifting transformer, and the two ends of the three rectifiers corresponding to the three secondary windings of the second phase-shifting transformer, which are sequentially coupled in series, are also coupled with the electric equipment.

At this time, according to pi/(3 n), n is the number of secondary windings included in the phase-shifting transformer, the first secondary winding t of the first phase-shifting transformer can be obtained₁₁And the second secondary winding t of the first phase-shifting transformer₁₂Has a phase difference of 20Second secondary winding t of first phase-shifting transformer₁₂And the third secondary winding t of the first phase-shifting transformer₁₃Is also 20 deg.. Similarly, the first secondary winding t of the second phase-shifting transformer₂₁And the second secondary winding t of the second phase-shifting transformer₂₂Is 20 deg., and a second secondary winding t of a second phase shifting transformer₂₂And the output voltage of the second phase-shifting transformer and the third secondary winding t of the second phase-shifting transformer₂₃The phase difference between the output voltages of (1) is 20 deg..

One secondary winding in the first phase-shifting transformer corresponds to one secondary winding in the second phase-shifting transformer, and the first secondary winding t of the first phase-shifting transformer can be obtained according to the number of the transformation units contained in the multi-pulse rectification circuit, wherein pi/(3 nm) and m are the number of the transformation units contained in the multi-pulse rectification circuit₁₁And the output voltage of the first secondary winding t of the second phase-shifting transformer₂₁Has a phase difference of 10 DEG between the output voltages, and a second secondary winding t of the first phase-shifting transformer₁₂And the second secondary winding t of the second phase-shifting transformer₂₂Is also 10 deg., the third secondary winding t of the first phase-shifting transformer₁₃And the output voltage of the second phase-shifting transformer and the third secondary winding t of the second phase-shifting transformer₂₃Is also 10 deg..

In some possible embodiments, to facilitate the production of the phase-shifting transformer, a first secondary winding t is included in the first phase-shifting transformer₁₁Has a phase angle of-25 DEG, and a second secondary winding t included in the first phase-shifting transformer₁₂Has a phase angle of-5 DEG, and a third secondary winding t included in the first phase-shifting transformer₁₃The phase angle of the output voltage of (2) is 15 deg.. First secondary winding t of second phase-shifting transformer₂₁Has a phase angle of 25 DEG, and a second secondary winding t of a second phase-shifting transformer₂₂Has a phase angle of 5 DEG, and a third secondary winding t of the second phase-shifting transformer₂₃The phase angle of the output voltage of (a) is-15 deg.. In general, each secondary winding of the first phase-shifting transformerThe phase angles of the groups are-25 deg. -5 deg. and 15 deg., respectively, and the phase angles corresponding to the output voltages of the respective secondary windings included in the second phase-shifting transformer are-15 deg. -5 deg. and 25 deg., respectively. It can be seen that the phase angles of the secondary windings included in the first phase-shifting transformer and the phase angles of the secondary windings included in the second phase-shifting transformer are opposite numbers, and at this time, the first phase-shifting transformer and the second phase-shifting transformer are considered to be symmetrical, that is, the windings of the first phase-shifting transformer and the second phase-shifting transformer can be the same, the processing technology can be the same, and the production is facilitated.

In order to illustrate the effect of reducing the harmonic content in the embodiment of the present application, the inventor of the present application performs simulation analysis on a multi-pulse rectifier circuit with 10kV three-phase voltage input, 800V dc output, and 800kW load, and specific simulation effects can be seen in fig. 8A to fig. 9. First, waveforms of the three-phase input voltage and the three-phase output voltage of the multi-pulse rectification circuit can be obtained by the controller as shown in fig. 8A, and waveforms of the three-phase input current and the three-phase output current of the multi-pulse rectification circuit can be further obtained by the controller as shown in fig. 8B. The harmonic content is understood to be a harmonic component of the output signal more than the input signal, and the harmonic component in the present application may be, for example, a harmonic component of the three-phase output voltage more than the three-phase input voltage in fig. 8A, or a harmonic component of the three-phase output current more than the three-phase input current in fig. 8B. In a specific implementation, a fast fourier transform FFT analysis may be performed on fig. 8A or fig. 8B to obtain an FFT analysis simulation diagram as shown in fig. 9. As can be obtained from fig. 9, at a frequency of 50Hz, the THD of the multi-pulse rectification circuit provided by the present application is 2.94%, that is, the current THD required by the national standard is less than 4%, which can meet the requirement of actual production.

It should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The above-described embodiments are merely illustrative, for example, the division of the unit is only a logical functional division, and there may be other division ways in actual implementation, such as: multiple units or components may be combined, or may be integrated into another system.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.