CN214544143U

CN214544143U - Power unit and three-level power converter

Info

Publication number: CN214544143U
Application number: CN202120666763.5U
Authority: CN
Inventors: 吴红杰; 包宝军; 韩腾; 周红; 汤周顺
Original assignee: Vertiv Tech Co Ltd
Current assignee: Weidi new energy Co.,Ltd.
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2021-10-29
Anticipated expiration: 2031-03-31

Abstract

A power unit and a three-level power converter comprise a direct-current laminated busbar, an alternating-current output copper bar, a first connecting busbar, a second connecting busbar, a first switching device module, a second switching device module and a third switching device module. The first end of the first switching device module is connected with the anode of the direct current laminated busbar, the second end of the first switching device module is connected with the neutral point of the direct current laminated busbar, and the third end of the first switching device module is connected with the first connecting busbar. The first end of the second switching device module is connected with the first connecting busbar, the second end of the second switching device module is connected with the second connecting busbar, and the third end of the second switching device module is connected with the alternating current output copper bar. The first end of the third switching device module is connected with the neutral point of the direct current laminated busbar, the second end of the third switching device module is connected with the negative electrode of the direct current laminated busbar, and the third end of the third switching device module is connected with the second connecting busbar. The first, second and third switching device modules are sequentially horizontally arranged in a straight line shape to optimize current sharing and heat dissipation, reduce the area of a radiator and the number of driving boards, simplify module design and reduce cost.

Description

Power unit and three-level power converter

Technical Field

The present invention relates to the field of power converters, and more particularly, to a power unit and a three-level power converter including the same.

Background

Frequency converters are widely used in industrial fields and are being developed in the direction of high voltage, large current, high power density, high reliability and low cost. In the field of high-voltage frequency conversion, the power conversion part of the frequency converter is limited by the performance of a semiconductor device, and a diode clamping three-level topological structure is generally adopted for power conversion. Fig. 1 shows a circuit diagram of a one-phase circuit in a typical three-level topology. As shown in fig. 1, T1, T2, T3 and T4 are controllable semiconductor switching devices, D1-D6 are freewheeling diodes, the controllable semiconductor switching devices T5-T6 corresponding to D5 and D6 are not shown, T1-T6 and the corresponding freewheeling diodes D1-D6 respectively form switching device modules M1, M2 and M3, and each of the switching device modules M1, M2 and M3 includes two controllable semiconductor switching devices connected in series.

In prior art three-level power converters, the switching device modules M1, M2, and M3 are typically distributed in a wye. The distribution mode has the defects of poor flow equalization performance and uneven heat dissipation among bridge arms, large area of a required radiator, high cost, large quantity of required driving plates and complex layout.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a power unit and a three-level power converter, aiming at the above-mentioned defects in the prior art, by arranging the switch device modules in a straight line shape, the current sharing and heat dissipation are optimized by connecting the switch devices in parallel, the area of the heat sink and the number of the driving boards are reduced, and thus, the module design is simplified and the cost is reduced.

The technical scheme adopted by the invention for solving the technical problems is as follows: a power unit is constructed, which comprises a direct current laminated busbar, an alternating current output copper bar, a first connecting busbar, a second connecting busbar, a first switching device module, a second switching device module and a third switching device module, the first end of the first switch device module is connected with the anode of the direct current laminated busbar, the second end is connected with the neutral point of the direct current laminated busbar, the third end is connected with the first connecting busbar, the first end of the second switching device module is connected with the first connecting bus bar, the second end of the second switching device module is connected with the second connecting bus bar, the third end of the second switching device module is connected with the alternating current output copper bar, the first end of the third switching device module is connected with the neutral point of the direct current laminated busbar, the second end of the third switching device module is connected with the negative electrode of the direct current laminated busbar, the third end of the third switching device module is connected with the second connecting busbar, the first switching device module, the second switching device module and the third switching device module are sequentially and horizontally arranged in a straight line shape.

In the power unit according to the present invention, the first switching device module and the third switching device module have the same layout and are opposite to the layout of the second switching device module.

In the power unit of the invention, the first switching device module comprises at least two parallel first IGBT modules, the second switching device module comprises at least two parallel second IGBT modules, the third switching device module comprises at least two parallel third IGBT modules, and the first IGBT module, the second IGBT module and the third IGBT modules are sequentially and horizontally arranged in a straight line.

In the power unit, the first IGBT module includes a first IGBT, a first freewheeling diode, a second IGBT, and a second freewheeling diode, the first IGBT and the second IGBT are connected in series, the first freewheeling diode and the second freewheeling diode are respectively connected in parallel with the first IGBT and the second IGBT, a P pole of the first IGBT and a P pole of the second IGBT are connected to an anode of the dc laminated busbar, an N pole of the first IGBT and the second IGBT is connected to a neutral point of the dc laminated busbar, and an output end of the first IGBT and the second IGBT is connected to the first connecting busbar.

In the power unit, the second IGBT module includes a third IGBT, a third freewheeling diode, a fourth IGBT, and a fourth freewheeling diode, the third IGBT and the fourth IGBT are connected in series, the third freewheeling diode and the fourth freewheeling diode are respectively connected in parallel with the third IGBT and the fourth IGBT, the P-poles of the third IGBT and the fourth IGBT are connected to the first connecting busbar, the N-poles of the third IGBT and the fourth IGBT are connected to the second connecting busbar, and the output end of the third IGBT and the fourth IGBT is connected to the ac output copper bar.

In the power unit, the third IGBT module includes a fifth IGBT, a fifth freewheeling diode, a sixth IGBT, and a sixth freewheeling diode, the fifth IGBT and the sixth IGBT are connected in series, the fifth freewheeling diode and the sixth freewheeling diode are respectively connected in parallel with the fifth IGBT and the sixth IGBT, a P pole of the fifth IGBT and a P pole of the sixth IGBT are connected to a neutral point of the dc laminated busbar, an N pole of the fifth IGBT and the sixth IGBT is connected to a negative pole of the dc laminated busbar, and an output end of the fifth IGBT and the sixth IGBT is connected to the second connection busbar.

In the power unit of the present invention, the power unit further includes an anode dc capacitor respectively disposed between the anode of the dc laminated busbar and the second end of each of the first switching device module, the second switching device module, and the third switching device module; and/or

And the negative direct-current capacitors are respectively arranged between the negative electrode of the direct-current laminated busbar and the second ends of the first switching device module, the second switching device module and the third switching device module.

The power unit further comprises an IGBT drive board, wherein the IGBT drive board is arranged above or below the first IGBT module, the second IGBT module and the third IGBT module which are sequentially and horizontally arranged in a straight line and is respectively connected with the first IGBT module, the second IGBT module and the third IGBT module through drive output ports of the IGBT drive board.

The power unit further comprises a cooling suction fan which is arranged in the center of one side, close to the output ends of the first IGBT module and the third IGBT module, of the first IGBT module, the second IGBT module and the third IGBT module which are sequentially arranged in a horizontal line.

In order to solve the technical problem, the invention adopts another technical scheme that a three-level power converter is constructed, and comprises a plurality of power units which are connected in parallel, wherein the power units are arranged in the power units.

According to the power unit and the three-level power converter, the switch device modules are arranged in a straight line shape, so that current sharing and heat dissipation are optimized through parallel connection of the switch devices, the area of a heat radiator and the number of driving boards are reduced, the module design is simplified, and the cost is reduced.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 shows a circuit diagram of a one-phase circuit in a typical diode-clamped three-level topology;

FIG. 2 is a functional block diagram of a preferred embodiment of the power cell of the present invention;

FIG. 3 is a functional block diagram of yet another preferred embodiment of the power cell of the present invention;

fig. 4 shows the positional relationship of the dc capacitance and the IGBT module according to the preferred embodiment of the present invention;

FIG. 5 is a functional block diagram of yet another preferred embodiment of the power cell of the present invention;

fig. 6 is a functional block diagram of a preferred embodiment of the three-level power converter of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention relates to a power unit and a three-level power converter. The power unit comprises a direct current laminated busbar, an alternating current output copper bar, a first connecting busbar, a second connecting busbar, a first switching device module, a second switching device module and a third switching device module, the first end of the first switch device module is connected with the anode of the direct current laminated busbar, the second end is connected with the neutral point of the direct current laminated busbar, the third end is connected with the first connecting busbar, the first end of the second switching device module is connected with the first connecting bus bar, the second end of the second switching device module is connected with the second connecting bus bar, the third end of the second switching device module is connected with the alternating current output copper bar, the first end of the third switching device module is connected with the neutral point of the direct current laminated busbar, the second end of the third switching device module is connected with the negative electrode of the direct current laminated busbar, the third end of the third switching device module is connected with the second connecting busbar, the first switching device module, the second switching device module and the third switching device module are sequentially and horizontally arranged in a straight line shape. According to the invention, the switch device modules are arranged in a straight line shape, so that the current sharing and heat dissipation are optimized through the parallel connection of the switch devices, the area of a heat radiator and the number of driving boards are reduced, the module design is simplified and the cost is reduced.

Fig. 2 is a schematic block diagram of a preferred embodiment of the power cell of the present invention. As shown in fig. 2, the power unit includes a dc laminated busbar, an AC output busbar AC, a first connecting busbar 4, a second connecting busbar 5, a first switching device module 10, a second switching device module 20, and a third switching device module 30. As shown in fig. 2, a first terminal P of the first switching device module 10 is connected to the positive electrode 1 of the dc laminated busbar, a second terminal N is connected to the neutral point 2 of the dc laminated busbar, and a third terminal OUT is connected to the first connecting busbar 4. The first end P of the second switching device module 20 is connected to the first connecting busbar 4, the second end N is connected to the second connecting busbar 5, and the third end OUT is connected to the AC output copper bar AC. The first end P of the third switching device module 30 is connected to the neutral point 2 of the dc laminated busbar, the second end N is connected to the negative electrode 3 of the dc laminated busbar, and the third end OUT is connected to the second connecting busbar 5. As shown in fig. 2, the first switching device module 10, the second switching device module 20, and the third switching device module 30 are sequentially arranged horizontally in a line, and the first switching device module 10 and the third switching device module 30 have the same layout and are opposite to the layout of the second switching device module 20.

In a preferred embodiment of the present invention, the first, second and third

switching device modules

10, 20 and 30 may include at least one IGBT module or MOS transistor module, respectively. Each IGBT module or MOS tube module comprises at least two IGBT or MOS tubes and a diode connected with the IGBT or MOS tubes in parallel. Each IGBT module or MOS tube module can adopt a 62mm packaging mode or an Econodeal packaging mode. In another preferred embodiment of the present invention, the first switching device module 10, the third switching device module 30, and the second switching device module 20 may have the same layout. As known to those skilled in the art, the power unit may further include components such as a dc capacitor, a heat sink, a driving adapter board, a driving board, an insulating member, and the like.

According to the power unit, the switch device modules are arranged in a straight line shape, so that current sharing and heat dissipation are optimized through parallel connection of the switch devices, the area of a heat radiator and the number of driving boards are reduced, the module design is simplified, and the cost is reduced.

Fig. 3 is a schematic block diagram of yet another preferred embodiment of the power cell of the present invention. As shown in fig. 3, the power unit includes a dc laminated busbar, an AC output busbar AC, a first connecting busbar 4, a second connecting busbar 5, a first switching device module, a second switching device module, and a third switching device module. In the preferred embodiment, the first switching device module 10 includes at least two parallel first IGBT modules M1, the second switching device module includes at least two parallel second IGBT modules M2, and the third switching device module 30 includes at least two parallel third IGBT modules M3.

In the preferred embodiment shown in fig. 3, the first IGBT module M1 may include a first IGBT T1, a first freewheel diode D1, a second IGBT, and a second freewheel diode D5, the first IGBT T1 and the second IGBT being connected in series, and the first freewheel diode D1 and the second freewheel diode D5 being connected in parallel with the first IGBT T1 and the second IGBT, respectively, as shown in fig. 1. The P poles of the first IGBT T1 and the second IGBT are connected with the positive pole 1 of the direct current laminated busbar, the N poles of the first IGBT T1 and the second IGBT are connected with the neutral point of the direct current laminated busbar, and the output end of the first IGBT T1 and the second IGBT is connected with the first connecting busbar 4. The second IGBT module M2 includes a third IGBT T2, a third freewheeling diode D2, a fourth IGBT T3, and a fourth freewheeling diode D3. The third IGBT T2 and the fourth IGBT T3 are connected in series, and the third freewheel diode D2 and the fourth freewheel diode D3 are connected in parallel with the third IGBT T2 and the fourth IGBT T3, respectively. The P poles of the third IGBT T2 and the fourth IGBT T3 are connected with the first connecting busbar 4, the N pole is connected with the second connecting busbar 5, and the output end is connected with the alternating current output copper bar AC. The third IGBT module M3 includes a fifth IGBT T4, a fifth freewheeling diode D4, a sixth IGBT and a sixth freewheeling diode D6, the fifth IGBT T4 and the sixth IGBT are connected in series, the fifth freewheeling diode D5 and the sixth freewheeling diode D6 are respectively connected in parallel with the fifth IGBT and the sixth IGBT, the P-pole of the fifth IGBT and the sixth IGBT is connected to the neutral point of the dc laminated busbar, the N-pole of the fifth IGBT and the sixth IGBT is connected to the negative electrode 3 of the dc laminated busbar, and the output end of the fifth IGBT and the sixth IGBT is connected to the second connection busbar 5.

As shown in fig. 3, two parallel first IGBT modules M1, two parallel second IGBT modules M2, and two parallel third IGBT modules M3 are sequentially horizontally arranged in a line. The P pole and the N pole of the first IGBT module M1 and the third IGBT module M3 face upward, and the output terminal OUT faces downward. The P and N poles of the second IGBT module M2 are down and the output terminal OUT is up. That is, the layouts of the first IGBT module M1 and the second IGBT module M2 are opposite, and the layouts of the first IGBT module M1 and the third IGBT module M3 are the same. Of course, those skilled in the art will appreciate that the arrangement may be reversed, i.e., the P and N poles of the first IGBT module M1 and the third IGBT module M3 are downward, and the output terminal OUT is upward, while the P and N poles of the second IGBT module M2 are upward, and the output terminal OUT is downward.

In a preferred embodiment of the present invention, each IGBT module may have a plurality of IGBTs, and each switching device module may also have a plurality of IGBT modules, thereby implementing power expansion.

Preferably, a dc capacitor may be disposed between the positive electrode 1 of the dc laminated busbar and the N-pole of each IGBT module. A dc capacitor may be provided between the negative electrode 3 of the dc laminated busbar and the N-pole of each IGBT module. All the direct current capacitors together form a bus capacitor. Of course, in the preferred embodiment of the present invention, the relative position of the IGBT module and the capacitor may be up or down, or left or right, for example, as shown in fig. 4. The control signal preferably takes into account the IGBT module settings. The DC side and AC side outputs of the power unit can be arranged in left and right or up and down.

Preferably, a cooling suction fan 50 may be disposed at a central position below (i.e., a side close to output ends of) the first IGBT module, the second IGBT module, and the third IGBT module, which are horizontally arranged in a line in sequence, so as to dissipate heat. Of course, in other preferred embodiments of the present invention, the cooling suction fan 50 may be disposed at other positions, and any suitable air cooling device with a single-sided layout design or water cooling device with a symmetrical layout design may be adopted. For example, the air duct used may blow or suck from the dc capacitor side to the IGBT side, or may blow or suck from the IGBT side to the capacitor side. Or blowing or sucking air from the alternating current side and the direct current side.

Fig. 5 is a schematic block diagram of yet another preferred embodiment of the power cell of the present invention. In the preferred embodiment shown in fig. 5, an IGBT driver board 40 is further shown. As shown in fig. 5, the IGBT driving board 40 is disposed below the first IGBT module M1, the second IGBT module M2, and the third IGBT module M3, which are horizontally arranged in a straight line, and is connected to the first IGBT module M1, the second IGBT module M2, and the third IGBT module M3 through driving output ports thereof, respectively. The IGBT driving board 40 may be disposed directly above or directly below all the IGBT modules, which reduces the length of the driving lines or eliminates the driving lines. According to the scheme, all IGBT modules can be driven by only one IGBT driving board. As can be seen from fig. 1, the IGBT T1 of the IGBT module M1 is physically located above the IGBT T3 of the IGBT module M2, and therefore its corresponding drive output port can be disposed above and to the left of the IGBT drive board 40. The IGBT T2 of the IGBT module M2 and the IGBT T4 of the IGBT module M3 are both below the physical location. And its corresponding drive output port is disposed at the lower right of the IGBT drive board 40. The driving adapter plate of the IGBT module can adopt one adapter plate independently designed for each IGBT, also can adopt one adapter plate designed by taking the IGBT modules M1, M3 and M2 as a group, also can adopt two driving adapter plates designed by being symmetrical in a central point mode or being symmetrical by rotating 180 degrees in a full-power unit mode, and also can adopt the design of one driving adapter plate shared by all IGBTs. Preferably, the IGBT driving board 40 and the driving adapter board may be connected by a wire, may directly use a plug interface, and may also use a flexible board. The drive output port may be provided at any position of the IGBT drive board 40, for example, above, below, left side, or right side.

According to the power unit, the switching device modules are connected in parallel and then form a three-level circuit with other groups, so that the possibility of uneven current is reduced; the switching devices are arranged in a straight line, so that the area of a radiator and the number of driving plates are reduced, the cost is optimized, and the driving plates are designed to enable the module layout to be simple and the driving wires to be simple. In addition, various parallel connection modes (namely, between power units and inside power units) can be adopted, and power expansion is facilitated.

Fig. 6 is a functional block diagram of a preferred embodiment of the three-level power converter of the present invention. As shown in fig. 6, the three-level power converter includes three-phase circuits, i.e., a U-phase circuit, a V-phase circuit, and a W-phase circuit, each of which may include at least one power cell, and preferably a plurality of power cells connected in parallel. A plurality of power units can form a wind energy converter of a grid side power part and a motor side power part in a parallel connection mode to adapt to different power grades. Based on the teachings of the present invention, one skilled in the art can implement various such three-level power converters, and will not be reiterated here.

According to the three-level power converter, the switching device modules are connected in parallel and then form a three-level circuit with other groups, so that the possibility of uneven current is reduced; the switching devices are arranged in a straight line, so that the area of a radiator and the number of driving plates are reduced, the cost is optimized, and the driving plates are designed to enable the module layout to be simple and the driving wires to be simple. In addition, various parallel connection modes (namely, between power units and inside power units) can be adopted, and power expansion is facilitated.

While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A power unit is characterized by comprising a direct current laminated busbar, an alternating current output copper bar, a first connecting busbar, a second connecting busbar, a first switching device module, a second switching device module and a third switching device module, the first end of the first switch device module is connected with the anode of the direct current laminated busbar, the second end is connected with the neutral point of the direct current laminated busbar, the third end is connected with the first connecting busbar, the first end of the second switching device module is connected with the first connecting bus bar, the second end of the second switching device module is connected with the second connecting bus bar, the third end of the second switching device module is connected with the alternating current output copper bar, the first end of the third switching device module is connected with the neutral point of the direct current laminated busbar, the second end of the third switching device module is connected with the negative electrode of the direct current laminated busbar, the third end of the third switching device module is connected with the second connecting busbar, the first switching device module, the second switching device module and the third switching device module are sequentially and horizontally arranged in a straight line shape.

2. The power cell of claim 1, wherein the first switching device module and the third switching device module have the same layout and an opposite layout as the second switching device module.

3. The power unit of claim 2, wherein the first switching device module comprises at least two parallel first IGBT modules, the second switching device module comprises at least two parallel second IGBT modules, and the third switching device module comprises at least two parallel third IGBT modules, and the first IGBT module, the second IGBT module, and the third IGBT modules are horizontally arranged in a straight line in sequence.

4. The power unit according to claim 3, wherein the first IGBT module comprises a first IGBT, a first freewheeling diode, a second IGBT and a second freewheeling diode, the first IGBT and the second IGBT are connected in series, the first freewheeling diode and the second freewheeling diode are respectively connected in parallel with the first IGBT and the second IGBT, the P poles of the first IGBT and the second IGBT are connected with the positive pole of the DC laminated busbar, the N poles of the first IGBT and the second IGBT are connected with the neutral point of the DC laminated busbar, and the output end of the first IGBT is connected with the first connecting busbar.

5. The power unit according to claim 3 or 4, wherein the second IGBT module comprises a third IGBT, a third freewheeling diode, a fourth IGBT and a fourth freewheeling diode, the third IGBT and the fourth IGBT are connected in series, the third freewheeling diode and the fourth freewheeling diode are respectively connected in parallel with the third IGBT and the fourth IGBT, the P poles of the third IGBT and the fourth IGBT are connected with the first connecting busbar, the N poles of the third IGBT and the fourth IGBT are connected with the second connecting busbar, and the output end of the third IGBT and the fourth IGBT is connected with the AC output copper bar.

6. The power unit according to claim 5, wherein the third IGBT module comprises a fifth IGBT, a fifth freewheeling diode, a sixth IGBT and a sixth freewheeling diode, the fifth IGBT and the sixth IGBT are connected in series, the fifth freewheeling diode and the sixth freewheeling diode are respectively connected in parallel with the fifth IGBT and the sixth IGBT, the P poles of the fifth IGBT and the sixth IGBT are connected with the neutral point of the DC laminated busbar, the N poles of the fifth IGBT and the sixth IGBT are connected with the negative pole of the DC laminated busbar, and the output end of the fifth IGBT and the sixth IGBT is connected with the second connecting busbar.

7. The power unit according to claim 3, further comprising a positive dc capacitor respectively disposed between the positive electrode of the dc laminated busbar and the second end of each of the first, second, and third switching device modules; and/or

8. The power unit according to claim 3, further comprising an IGBT drive board disposed above or below the first, second and third IGBT modules arranged in a horizontal row in this order and connected to the first, second and third IGBT modules through their drive output ports, respectively.

9. The power unit according to claim 8, further comprising a cooling suction fan disposed at a central position of one side of the first IGBT module, the second IGBT module, and the third IGBT module, which are horizontally arranged in line in this order, near the output ends of the first IGBT module and the third IGBT module.

10. A three-level power converter comprising a plurality of power cells connected in parallel, said power cells being according to any of claims 1-9.