A three-level inverter structure

Abstract

The present invention relates to the field of industrial automation technology, and specifically to a three-level inverter structure, comprising a plurality of module combinations and a DC capacitor assembly, wherein the module combination comprises three IGBT modules, the IGBT modules are provided with three wiring terminals, wherein two of the IGBT modules are arranged side by side, another IGBT module is vertically arranged on the remaining two IGBT modules, and the three IGBT modules are connected in parallel with a laminated copper busbar through the wiring terminals, and the laminated copper busbar is connected with a laminated busbar; the plurality of module combinations are connected with an integrated laminated busbar through the laminated busbar, the integrated laminated busbar is connected with a DC capacitor assembly, and two IGBT modules arranged side by side are connected with an absorption capacitor assembly through the wiring terminals; the present invention improves the utilization rate of the capacitor capacity, the parasitic inductance of the line, the reduction of the current loop and other aspects, effectively reduces the voltage stress of the module, and makes the inverter run more stably.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial automation, and in particular to a three-level frequency converter structure. Background Art

[0002] The three-level inverter is a special industrial product, different from the common two-level products on the market. Its circuit structure is complex and uses many modules. This causes a large amount of parasitic inductance in the electrical circuit. Since the IGBT, the core device of the inverter, works in a high-frequency switching state, voltage spikes are generated on the module under the combined effect. If the influence of parasitic parameters is not considered during design, the product will be difficult to operate stably.

[0003] The module layout structure used in the prior art has the characteristics of large current loop current and long distance between modules and capacitors. Other forms of single-phase grouped capacitor layouts affect the output of capacitor capacity and DC energy, resulting in low bus voltage and heating of the copper bar connecting the groups under voltage.

[0004] The usual way to deal with this problem is to use laminated busbars or integrated modules to reduce parasitic parameters, but this method has limited practical effect and is very costly. Summary of the invention

[0005] The object of the present invention is to provide a three-level inverter structure to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a three-level inverter structure, comprising a plurality of module combinations and a DC capacitor assembly, wherein the module combination comprises three IGBT modules, the IGBT modules are provided with three wiring terminals, wherein two of the IGBT modules (1) are arranged side by side in the longitudinal direction, another IGBT module (1) is arranged transversely above the other two IGBT modules (1), the three IGBT modules are connected in parallel with a laminated copper busbar through the wiring terminals, and the laminated copper busbar is connected with a laminated busbar; the plurality of module combinations are connected with an integrated laminated busbar through the laminated busbar, the integrated laminated busbar is connected with the DC capacitor assembly, and the two IGBT modules arranged side by side are connected with an absorption capacitor assembly through the wiring terminals.

[0007] Preferably, the three connection terminals of the IGBT module are respectively an OUT terminal, a negative terminal and a positive terminal.

[0008] Preferably, the DC capacitor assembly comprises a plurality of DC capacitors, and the plurality of DC capacitors are arranged side by side and connected in parallel with an integrated laminated busbar.

[0009] Preferably, the absorption capacitor assembly includes a plurality of absorption capacitors, and the plurality of absorption capacitors are connected in parallel to the IGBT module via a positive terminal and a negative terminal.

[0010] Preferably, the laminated copper busbar comprises a positive copper busbar and a negative copper busbar, an insulating layer is provided between the positive copper busbar and the negative copper busbar, the positive copper busbar connects the positive terminal of one IGBT module and the OUT terminal of another IGBT module, and the negative copper busbar connects the negative terminal of one IGBT module and the OUT terminal of another IGBT module.

[0011] Preferably, an OUT terminal of an IGBT module laterally arranged above in each group of the module combinations is connected to an output copper busbar.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The IGBT module layout mode of the present invention, the IGBT module connection copper bus lamination processing, the copper bus current forward and reverse overlapping design, and the single-phase module combination unit connected to the DC support capacitor nearby are different from the traditional circuit structure, and effectively avoid the problem of low bus voltage in the prior art and voltage heating of the copper bus connecting the groups, and improve the capacitor capacity utilization, line parasitic inductance, and reduction of current loops. The module voltage stress is effectively reduced, and the inverter operation is more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 It is a structural schematic diagram of the present invention;

[0016] Figure 2 The structure of the prior art is shown in FIG. Figure 1 ;

[0017] Figure 3 The structure of the prior art is shown in FIG. Figure 2 ;

[0018] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0019] 1 IGBT module, 2 terminal blocks, 3 laminated copper busbars, 4 laminated busbars, 5 integrated laminated busbars, 6 DC capacitors, 7 absorption capacitors, 8 output copper busbars, 9 connecting copper busbars. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See also Figure 1 The present invention provides a technical solution: a three-level inverter structure, comprising a plurality of module assemblies and a DC capacitor assembly, wherein the module assembly comprises three IGBT modules 1, the IGBT modules 1 are provided with three wiring terminals 2, wherein two of the IGBT modules (1) are arranged side by side in the longitudinal direction, and another IGBT module (1) is arranged transversely above the other two IGBT modules (1), the three IGBT modules 1 are connected in parallel with a laminated copper bus 3 through the wiring terminals 2, and the laminated copper bus 3 is connected with a laminated busbar 4; the plurality of module assemblies are connected with an integrated laminated busbar 5 through the laminated busbar 4, the integrated laminated busbar 5 is connected with the DC capacitor assembly, and the two IGBT modules 1 arranged side by side are connected with an absorption capacitor assembly through the wiring terminals 2.

[0022] The three connection terminals 2 of the IGBT module 1 are respectively an OUT terminal, a negative terminal and a positive terminal.

[0023] The DC capacitor assembly includes a plurality of DC capacitors 6 , which are arranged side by side and connected in parallel to the integrated laminated busbar 5 .

[0024] The absorption capacitor assembly includes a plurality of absorption capacitors 7 , and the plurality of absorption capacitors 7 are connected in parallel to the IGBT module 1 via a positive terminal and a negative terminal.

[0025] Among them, the laminated copper busbar 3 includes a positive copper busbar and a negative copper busbar, an insulating layer is provided between the positive copper busbar and the negative copper busbar, the positive copper busbar connects the positive terminal of one IGBT module 1 and the OUT terminal of another IGBT module 1, and the negative copper busbar connects the negative terminal of one IGBT module 1 and the OUT terminal of another IGBT module 1.

[0026] The OUT terminal of an IGBT module 1 disposed laterally above each module assembly is connected to an output copper bus 8 .

[0027] See also Figure 1 and Figure 2 or Figure 1 and Figure 3 The modules and their layout schemes currently used in other products have long current paths and loops, while the module layout method of the present invention has a short current path and no current loops.

[0028] The module connection copper bar of the present invention is specially laminated, while the copper bar 9 of the prior art is not processed. The laminated copper bar has no current loop, and the voltage peak is lower when the IGBT works at high frequency.

[0029] A plurality of absorption capacitors 7 are installed on the module of the present invention. In the existing technical solution, one absorption capacitor 7 is installed for each module. A greater number of absorption capacitors 7 provides a better peak absorption effect.

[0030] Each phase module combination of the present invention is connected to the integrated laminated busbar 5. A connection different from the existing method is adopted, which effectively improves the distance between the IGBT module 1 and the DC capacitor 6 and reduces the inductance value of the connecting copper busbar.

[0031] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0032] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0033] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made based on the content of this specification. This specification selects and describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can better understand and use the present invention. The present invention is limited by the claims and their full scope and equivalents.

Claims

1. A three-level inverter structure, comprising a plurality of module assemblies and a DC capacitor assembly, wherein the module assembly comprises three IGBT modules (1), the IGBT modules (1) are provided with three connection terminals (2), and characterized in that: Two of the IGBT modules (1) are arranged side by side in the longitudinal direction, another IGBT module (1) is arranged transversely above the other two IGBT modules (1), the three IGBT modules (1) are connected in parallel with a laminated copper busbar (3) via a wiring terminal (2), and the laminated copper busbar (3) is connected to a laminated busbar (4); a plurality of groups of the module combinations are connected to an integrated laminated busbar (5) via a laminated busbar (4), and the integrated laminated busbar (5) is connected to a DC capacitor component, two IGBT modules (1) arranged side by side are connected to an absorption capacitor component via a wiring terminal (2), and an OUT terminal of an IGBT module (1) arranged transversely above each group of the module combinations is connected to an output copper busbar (8).

2. A three-level inverter structure according to claim 1, characterized in that: The three connection terminals (2) of the IGBT module (1) are respectively an OUT terminal, a negative terminal and a positive terminal.

3. A three-level inverter structure according to claim 2, characterized in that: The DC capacitor assembly comprises a plurality of DC capacitors (6), wherein the plurality of DC capacitors (6) are arranged side by side and connected in parallel to an integrated laminated busbar (5).

4. A three-level inverter structure according to claim 2, characterized in that: The absorption capacitor assembly comprises a plurality of absorption capacitors (7), and the plurality of absorption capacitors (7) are connected in parallel to the IGBT module (1) via a positive terminal and a negative terminal.

5. A three-level inverter structure according to claim 2, characterized in that: The laminated copper bar (3) comprises a positive copper bar and a negative copper bar, an insulating layer is provided between the positive copper bar and the negative copper bar, the positive copper bar connects the positive terminal of one IGBT module (1) and the OUT terminal of another IGBT module (1), and the negative copper bar connects the negative terminal of one IGBT module (1) and the OUT terminal of another IGBT module (1).

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