Bus capacitor structure of inverter

Abstract

The utility model discloses a bus capacitor structure of an inverter. The structure comprises a bus capacitor plate, a bracket, a filter circuit and an impedance element, a plurality of bus capacitors are arranged on the bus capacitor plate, the bus capacitor plate is fixed on a power plate of the inverter through a bracket, so that a gap is formed between the bus capacitor plate and the power plate, and an inverter circuit and a switching circuit of the inverter are arranged on the power plate; the filter circuits are respectively arranged on the inverter circuit and the switch circuit on the power board, and the filter circuits are connected in series with the corresponding impedance elements. The problem that an inverter cannot pass an electromagnetic compatibility test due to the fact that an inverter bus capacitor frame plate in the prior art is prone to resonance is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inverters, in particular to a bus capacitor structure of an inverter. BACKGROUND

[0002] In the related art, the internal space of an inverter is limited, and the switching devices in the direct-current switching circuit and the inverter circuit, including IGBT (Insulated Gate Bipolar Transistor), MOSFET (Metal Oxide Semiconductor Field Effect Transistor), diode, etc., generate a large amount of heat. These switching devices need to be in close contact with the bottom of the shell for heat dissipation. Therefore, the bus capacitor can only be selected in the form of a bus capacitor rack plate.

[0003] However, in the prior art, the bus capacitor rack plate introduces additional parasitic inductance, which can cause the bus capacitor filtering effect to deteriorate. In addition, after the rack plate, the components on the bus capacitor-support-power plate can cause resonance, such as filter capacitors, resulting in very high resonance peaks in the conduction waveform of the direct current and alternating current ports of the inverter in the EMC (Electro Magnetic Compatibility) test, causing the product EMC test to fail.

[0004] Therefore, the bus capacitor rack plate of the inverter in the related art is prone to resonance, which can cause the inverter to fail the electromagnetic compatibility test. CONTENT OF THE UTILITY MODEL

[0005] The main purpose of the present application is to provide a bus capacitor structure of an inverter to solve the problem that the bus capacitor rack plate of the inverter in the related art is prone to resonance, which can cause the inverter to fail the electromagnetic compatibility test.

[0006] According to one aspect of the present application, a bus capacitor structure of an inverter is provided, including a bus capacitor plate, a support, a filter circuit, and an impedance element. The bus capacitor plate is provided with a plurality of bus capacitors, and the bus capacitor plate is fixed on the power plate of the inverter through the support, so that there is a gap between the bus capacitor plate and the power plate. The power plate is provided with an inverter circuit and a switching circuit of the inverter. The filter circuit is arranged on the inverter circuit and the switching circuit on the power plate respectively, and the filter circuit is connected in series with the corresponding impedance element.

[0007] As an optional embodiment, the plurality of bus capacitors are arranged on the bus capacitor board in the form of a capacitor group, the capacitor group comprising a plurality of bus capacitors; an input end of the capacitor group is connected to an output end of the switching circuit, and an output end of the capacitor group is connected to an input end of the inverter circuit; an input end of the switching circuit is connected to an output end of a direct-current filter circuit, an input end of the direct-current filter circuit is connected to an input end of the inverter, and the input end of the inverter is connected to a direct-current power supply; an output end of the inverter circuit is connected to an input end of an alternating-current filter circuit, and an output end of the alternating-current filter circuit is connected to an output end of the inverter, and the output end of the inverter is connected to an alternating-current power supply.

[0008] As an optional embodiment, the filter circuit is a filter capacitor; the input end of the inverter circuit is provided with a first filter capacitor; and the output end of the switching circuit is provided with a second filter capacitor.

[0009] As an optional embodiment, the first filter capacitor and the second filter capacitor are both arranged on the power board; the distance between the input end of the inverter circuit and the first filter capacitor on the power board is not more than a preset distance; and the distance between the output end of the switching circuit and the second filter capacitor on the power board is not more than a preset distance.

[0010] As an optional embodiment, the first filter capacitor and the second filter capacitor are both connected in series with corresponding damping elements.

[0011] As an optional embodiment, the number of the first filter capacitors is proportional to the number of bridge arms of the inverter circuit, and each of the first filter capacitors is connected in series with a corresponding damping element.

[0012] As an optional embodiment, the number of the first filter capacitors is the same as the number of bridge arms of the inverter circuit; and when the number of bridge arms of the inverter circuit is two, the number of the first filter capacitors is two.

[0013] As an optional embodiment, the filter capacitor is a thin-film capacitor; and the damping element is a magnetic bead.

[0014] As an optional embodiment, the support is a plurality of electrically conductive metal columns, the plurality of metal columns comprising a first metal column and a second metal column; the first metal column is connected to the input end of the inverter circuit and the output end of the capacitor group; and the second metal column is connected to the output end of the switching circuit and the input end of the capacitor group.

[0015] According to another aspect of the present application, an inverter is provided, comprising a power board, an inverter circuit and a switching circuit arranged on the power board, and the bus capacitor structure according to any one of the above.

[0016] In the application, the bus capacitor plate is fixed on the power plate of the inverter through the support, so that there is a gap between the bus capacitor on the bus capacitor plate and the power plate, which further reduces the volume and saves the space of the inverter without heating the bus capacitor. The inverter circuit and the switching circuit of the inverter are arranged on the power plate, and the inverter circuit and the switching circuit on the power plate are both provided with a filter circuit, which can reduce the high-frequency loop impedance and avoid the resonance of the bus capacitor-support-power plate, thereby avoiding the problem that the electromagnetic compatibility test fails. BRIEF DESCRIPTION OF DRAWINGS

[0017] The drawings described herein are used to provide further understanding of the application, and form a part of the application. The illustrative embodiments of the application and their descriptions serve to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0018] Figure 1 It is a schematic diagram of the bus capacitor structure of the inverter disclosed in the application;

[0019] Figure 2 It is a schematic diagram of the bus capacitor and the circuits of the inverter disclosed in the application;

[0020] Figure 3 It is a schematic diagram of the equivalent circuit of the bus capacitor, the support and the inverter circuit disclosed in the application;

[0021] Figure 4 It is a schematic diagram of the input impedance principle circuit disclosed in the application;

[0022] Figure 5 It is a schematic diagram of the input impedance of the inverter circuit and the frequency relationship disclosed in the application;

[0023] Figure 6 It is a schematic diagram of the conducted test result of the inverter disclosed in the application;

[0024] Figure 7 It is a schematic diagram of the input impedance of the inverter circuit and the frequency relationship before and after the series magnetic beads disclosed in the application;

[0025] Figure 8 It is a schematic diagram of the conducted test result of the inverter after the series magnetic beads disclosed in the application. DETAILED DESCRIPTION

[0026] It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict. The application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0027] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0028] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the present application unless otherwise specifically stated. It is to be understood that the actual dimensions of the various parts shown in the drawings are not necessarily to scale. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as if the techniques, methods, and apparatus were discussed in detail. In all examples shown and discussed herein, any specific values are to be interpreted as illustrative only and not as limiting. Thus, other examples of example embodiments can have different values. It is noted that like numbers and letters on the figures identify like parts throughout the disclosure, and thus, once one part is defined in one figure, it is not necessary to discuss it further in connection with other figures.

[0029] In the related art, the bus capacitor bracket plate introduces additional parasitic inductance, which causes the bus capacitor filtering effect to be poor. In addition, after the bracket plate, the bus capacitor-metal column-power plate components will cause resonance, resulting in very high resonance peaks in the conductive waveform of the DC and AC ports of the inverter in the EMC test, causing the product EMC test to fail.

[0030] In order to solve the problem that the bus capacitor bracket of the inverter in the related art is prone to resonance, which causes the inverter to fail in electromagnetic compatibility test, the embodiment provides a bus capacitor structure of an inverter, Figure 1 FIG. 1 is a schematic diagram of a bus capacitor structure of an inverter disclosed by the present application, Figure 2 FIG. 2 is a schematic diagram of a bus capacitor and various circuits of an inverter disclosed by the present application, as Figures 1 to 2 As shown in the figure, the bus capacitor structure includes a bus capacitor plate, a bracket, and a filter circuit.

[0031] A plurality of bus capacitors are arranged on the bus capacitor plate, and the bus capacitor plate is fixed on the power plate of the inverter through the bracket, so that there is a gap between the bus capacitor plate and the power plate, wherein the power plate is provided with an inverter circuit and a switching circuit of the inverter; the filter circuit is arranged on the inverter circuit and the switching circuit on the power plate, respectively.

[0032] The bus capacitor plate is fixed on the power plate of the inverter through the support, so that the bus capacitor on the bus capacitor plate has a gap with the power plate, and the volume of the power plate is further reduced, and the space of the inverter is saved.

[0033] The inverter circuit and the switching circuit of the inverter are arranged on the power plate, and the inverter circuit and the switching circuit on the power plate are both provided with filter circuits, so that the high-frequency loop impedance can be reduced, and the resonance of the bus capacitor-support-power plate is avoided, so that the problem of failing to pass the electromagnetic compatibility test is avoided.

[0034] As shown in Figure 1 , a plurality of bus capacitors are arranged on the bus capacitor plate, and the bus capacitor plate is fixed on the power plate through the support, and the power plate has a certain gap with the bus capacitor plate. The gap needs to ensure that it does not affect the work of the components on the power plate, and to a certain extent, it avoids affecting the heat dissipation performance.

[0035] Through the way of dividing the board and supporting, the space of the bus capacitor on the power plate can be reduced, the volume of the power plate can be further reduced, and the space occupation of the inverter can be reduced.

[0036] As shown in Figure 2 , the switching circuit and the inverter circuit on the power plate are both provided with filter capacitors, which is to improve the high-frequency performance of the EMC test. If the switching circuit and the inverter circuit on the power plate do not have filter capacitors, resonance will not occur, but the high-frequency performance of the EMC test will be poor, and the electrical stress of the MOS tube of the inverter circuit will be a problem.

[0037] Figure 2 In the middle, the switching circuit and the inverter circuit are both provided with filter capacitors, such as C2, C3 and C5. The filter capacitors C2, C3 and C5 of the bus capacitor-support-power plate will resonate with each other. In order to avoid the resonance of the three, the filter capacitors C2, C3 and C5 are all connected in series with magnetic beads, such as FB1, FB2 and FB3 in the figure. The magnetic beads here are a specific embodiment of the above-mentioned impedance element.

[0038] As an optional embodiment, a plurality of bus capacitors are arranged on the bus capacitor plate in the form of a capacitor group, the capacitor group includes a plurality of bus capacitors; the input end of the capacitor group is connected with the output end of the switching circuit, and the output end of the capacitor group is connected with the input end of the inverter circuit; the input end of the switching circuit is connected with the output end of the direct-current filter circuit, the input end of the direct-current filter circuit is connected with the input end of the inverter, and the input end of the inverter is connected with a direct-current power supply; the output end of the inverter circuit is connected with the input end of the alternating-current filter circuit, the output end of the alternating-current filter circuit is connected with the output end of the inverter, and the output end of the inverter is connected with an alternating-current power supply.

[0039] In the inverter, multiple bus capacitors are connected in series and parallel to form a capacitor bank, which can be equivalent to a capacitor. Figure 2 C4 in.

[0040] like Figure 2 As shown, the input of the capacitor bank is connected to the output of the switching circuit, and the output of the capacitor bank is connected to the input of the inverter circuit. The input of the switching circuit is connected to the output of the DC filter circuit, which is connected to the input of the inverter, which is connected to a DC power supply (DC). The output of the inverter circuit is connected to the input of the AC filter circuit, which is connected to the output of the inverter, which is connected to an AC power supply (AC).

[0041] Since the above-mentioned switching circuit is connected to a DC power supply, it is a DC switching circuit, and the DC switching circuit can be a DC boost circuit. Figure 2 The structure of the circuit is the same as that of the boost circuit in the prior art, including C1, L1, Q5 and a diode.

[0042] As an optional embodiment, the filter circuit is a filter capacitor; the input end of the inverter circuit is provided with a first filter capacitor; the output end of the switch circuit is provided with a second filter capacitor.

[0043] The filter circuit is mainly used on the power board to improve the high-frequency performance of the EMC test and to avoid the electrical stress generated by the MOS tube of the inverter circuit. It can be a filter or a general filter circuit. In this embodiment, the filter circuit is a filter capacitor, such as Figure 2 As shown, the filter capacitors may be C2, C3 and C5.

[0044] The input end of the inverter circuit is provided with first filter capacitors C3 and C5, and the output end of the switch circuit is provided with a second filter capacitor C2.

[0045] As an optional embodiment, the first filter capacitor and the second filter capacitor are both arranged on the power board; the distance between the input end of the inverter circuit and the first filter capacitor on the power board does not exceed a preset distance; the distance between the output end of the switching circuit and the second filter capacitor on the power board does not exceed a preset distance.

[0046] The first filter capacitors C3 and C5, as well as the second filter capacitor C2, are all mounted on the power board. The distance between the input of the inverter circuit and the first filter capacitor on the power board should not exceed a preset distance; the distance between the output of the switching circuit and the second filter capacitor on the power board should not exceed a preset distance. This is to ensure the filtering effect of the filter capacitors; excessive distance will degrade the filtering effect.

[0047] On the other hand, the short distance can also save the area and space of the power board.

[0048] As an optional embodiment, the first filter capacitor and the second filter capacitor are both in series with a damping element.

[0049] After the filter capacitor is set, although it can be filtered, the filter capacitor-metal column-bus capacitor plate three may also resonate, thereby causing the inverter AC conduction and DC conduction to exceed the standard, therefore, in series with a damping element for each filter capacitor, which can effectively avoid the generation of new resonance.

[0050] As an optional embodiment, the number of the first filter capacitors is proportional to the number of bridge arms of the inverter circuit, and each of the first filter capacitors is in series with a corresponding damping element.

[0051] The first filter capacitors on the inverter circuit can be adjusted according to the number of bridge arms of the inverter circuit, and in theory, the more the number of bridge arms, the more the first filter capacitors. The common bridge arm number can be two, three, four. The corresponding first filter capacitors can be set to two, three, four to avoid interference between different bridge arms.

[0052] As an optional embodiment, the number of the first filter capacitors is the same as the number of bridge arms of the inverter circuit, and in the case of two bridge arms of the inverter circuit, the number of the first filter capacitors is two.

[0053] The number of bridge arms of the inverter of the embodiment is two, and the corresponding first filter capacitors are two.

[0054] It should be noted that the second filter capacitor of the switching circuit is usually one.

[0055] As an optional embodiment, the filter capacitor is a film capacitor; and the damping element is a magnetic bead.

[0056] Both the film capacitor and the magnetic bead have the advantages of small size, low cost, and good filtering effect.

[0057] As an optional embodiment, the support is a plurality of conductive metal columns, and the plurality of metal columns include a first metal column and a second metal column; the first metal column is connected with the input end of the inverter circuit and the output end of the capacitor group; and the second metal column is connected with the output end of the switching circuit and the input end of the capacitor group.

[0058] The support adopts a metal column, which can facilitate the circuit connection and signal transmission of the bus capacitor plate and the power plate.

[0059] It should be noted that the embodiment also provides an optional implementation, which will be described in detail below.

[0060] The embodiment provides a bus capacitor structure, in order to reduce the volume, the bus capacitor plate is divided into plates, and the plates are arranged on the power plate through metal columns. Figure 2 The direct-current switch circuit (for example, a boost circuit) and the inverter circuit are arranged on the power plate. Meanwhile, the film capacitors are arranged close to the input of the inverter circuit and the output of the direct-current switch circuit on the power plate. Figure 2 In the embodiment, C2, C3 and C5 are film capacitors, and the typical values are dozens of nF to several uF, so as to reduce the high-frequency loop impedance. The number of the film capacitors can be adjusted according to the actual number of the inverter bridge.

[0061] In order to avoid resonance of the film capacitor, the metal column and the bus capacitor plate, which causes the inverter AC conduction emission and the direct-current conduction emission to exceed the standard, a magnetic bead is connected in series with each film capacitor. Figure 2 In the embodiment, FB1, FB2 and FB3 are magnetic beads.

[0062] The bus capacitor, the film capacitor and the metal column can cause resonance, which causes resonance peaks of the direct-current conduction and the AC conduction. The resonance peaks can cause the volume of the filter circuit on the direct-current side and the AC side to be large, which is not conducive to miniaturization.

[0063] The mechanism of the resonance is described below by taking the inverter circuit as an example, and the resonance of the direct-current conversion circuit is similar.

[0064] In the frequency band (150 kHz-30 MHz) of the EMC conduction emission test, the bus capacitor, the film capacitor and the column of the bus capacitor plate are no longer ideal devices, and have high-frequency parasitic parameters. A simple circuit model considering the high-frequency parasitic parameters of the bus capacitor, the film capacitor and the column is as shown in Figure 3 . Figure 3 The figure is an equivalent circuit of the bus capacitor, the bracket and the inverter circuit disclosed by the application. The principle of defining the input impedance is as shown in Figure 4 . Figure 4 The figure is a schematic diagram of the principle circuit for defining the input impedance disclosed by the application, and is used for analyzing how the resonance of the three is generated and for facilitating the definition of the input impedance Z.

[0065] Figure 3 In the embodiment, LC4 and RC4 are the parasitic inductance and the parasitic resistance of the bus capacitor, L4 and L5 are the parasitic inductance of the column, and LC3, RC3, LC5 and RC5 are the parasitic inductance and the parasitic resistance of the inverter film capacitors C3 and C5. Figure 3The dotted line with the middle arrow is the propagation path of the noise generated by the switch tubes Q1 and Q3. For the convenience of analysis, the high-frequency parasitic parameters of the inverter inductance, the magnetic beads of the film capacitor string, the DC conversion circuit and other devices are not included in the circuit. In addition, in the actual PCB layout, C3 is arranged close to Q1 and Q3, and C5 is placed close to Q2 and Q4, so the influence of C5 is also ignored when analyzing the propagation path of the noise generated by Q1 and Q3.

[0066] The impedance Z at the input side of the inverter circuit can be equivalent to the bus capacitor in series with the column, and then in parallel with the inverter film capacitor. The smaller the input side impedance, the better the filtering effect. The larger the input side impedance, the worse the filtering effect.

[0067] As shown in Figure 4 , according to the design example, the value of 4 is taken as 2000uF, C the value of 3 is taken as 150nF, L C4 the value of 5 is taken as 25nH, R C4 the value of 4 is taken as 20mΩ, L 4 L the value of 5 is taken as 25nH, C 3 is taken as 150nF, L C3 the value of 4 is taken as 14nH, R C3 the value of 4 is taken as 50mΩ. The relationship between the input impedance Z and the frequency can be plotted as shown in Figure 5 , Figure 5 is a schematic diagram of the input impedance of the inverter circuit disclosed in the present application and the frequency relationship.

[0068] It can be seen that the circuit has two resonance points near 1.48M and 3M, and the resonance point of 1.48M is a maximum value. This shows that the filtering circuit composed of the bus capacitor + metal column + inverter film capacitor has the worst filtering effect at 1.48M. When conducting the test, a resonance peak will appear at this frequency, resulting in a failed test. The inverter film capacitor is the film capacitor of the inverter circuit, which is equivalent to the second filtering capacitor described above. The film capacitor is a short name for the film capacitor.

[0069] Figure 6 is a schematic diagram of the conduction test results of the inverter disclosed in the present application, as shown in Figure 6 , the conduction test results of the inverter can be seen, and the level maximum values of the peak curve PK and the average value curve AV at 1.48M are all higher than the corresponding limit lines, which will result in a failed test, which is basically consistent with the analysis above Figure 5 .

[0070] It should be noted that, Figure 6The peak curve PK in the figure is the industry test standard, the general quasi-peak value QP is lower than the peak value PK, and the quasi-peak curve scanning time is longer, and the peak curve PK scanning time is shorter. Therefore, the general initial scanning will scan the peak curve PK and the average value curve AV.

[0071] If the peak curve PK exceeds the quasi-peak limit value QP, the quasi-peak QP in the frequency band will be scanned. If the quasi-peak QP in the frequency band is lower than the quasi-peak limit value limit: QP, it is also considered to pass the test. This step is also called final scanning.

[0072] Because the magnetic beads themselves have a certain impedance, when the film capacitor string is inserted into the magnetic beads, the strength of the resonance can be relieved.

[0073] Figure 7 The input impedance and frequency relationship diagram of the inverter circuit before and after the series magnetic beads disclosed in the application is shown in Figure 7 The impedance curve before the magnetic beads are inserted and the impedance curve after the magnetic beads are inserted can be seen, and the resonance point frequency point is shifted forward and the amplitude attenuation is obvious after the magnetic beads are inserted, proving that the low-frequency filtering effect is obviously improved.

[0074] Figure 8 The conduction test result diagram of the inverter after the series magnetic beads disclosed in the application is shown in Figure 8 The peak curve PK and the average value curve AV are both normal fluctuations and will not exceed the corresponding limit line. Compared with Figure 6 The resonance point frequency point is shifted forward and the amplitude attenuation is obvious after the magnetic beads are inserted, proving that the low-frequency filtering effect is obviously improved.

[0075] The embodiment reduces the power plate area through the electrolytic capacitor rack, thereby realizing the overall volume reduction of the inverter. The resonance caused by the film capacitor-metal column-bus capacitor plate is relieved by the series magnetic beads of the power plate film capacitor, and the resonance peak caused by the direct current conduction and alternating current conduction test of the inverter is avoided.

[0076] The embodiment can also increase the film capacitor value on the power plate, so as to shift the resonance point to below 150 kHz. However, the height and bottom area of the large-capacitance film capacitor will increase a lot, so the power plate area and the rack height must be increased accordingly. The actual product volume will not be reduced much.

[0077] The embodiment can also directly remove the film capacitor: which will cause the inverter tube electric stress to be large; which will make the circuit high-frequency filtering effect worse, and additional filtering circuit needs to be added.

[0078] According to another aspect of the application, an inverter is provided, comprising a power plate, an inverter circuit and a switching circuit arranged on the power plate, and the bus capacitor structure of any one of the above.

[0079] The inverter has all the features of the bus capacitor structure described above, and can correspond to all the technical effects of the bus capacitor structure described above, which will not be repeated here.

[0080] For ease of description, spatial relative terms such as "over", "above", "upper surface", "upper", etc. can be used herein to describe a spatial positional relationship of one device or feature to other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the drawings. For example, if the device in the drawings is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0081] In addition, it should be noted that the use of "first", "second", and the like words to qualify parts is only for the convenience of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated, and therefore cannot be understood as limiting the scope of protection of the present application.

[0082] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A busbar capacitor structure of an inverter, characterized in that: Including busbar capacitor plate, bracket, filter circuit, impedance element; The bus capacitor plate is provided with a plurality of bus capacitors, and the bus capacitor plate is fixed to the power board of the inverter through the bracket, so that there is a gap between the bus capacitor plate and the power board, wherein the inverter circuit and the switching circuit of the inverter are provided on the power board; The filter circuits are respectively arranged on the inverter circuit and the switch circuit on the power board, and the filter circuits are connected in series with corresponding impedance elements.

2. The busbar capacitor structure of the inverter according to claim 1, characterized in that: The plurality of bus capacitors are arranged on the bus capacitor plate in the form of a capacitor group, and the capacitor group includes the plurality of bus capacitors; The input end of the capacitor group is connected to the output end of the switch circuit, and the output end of the capacitor group is connected to the input end of the inverter circuit; The input end of the switching circuit is connected to the output end of the DC filter circuit, the input end of the DC filter circuit is connected to the input end of the inverter, and the input end of the inverter is connected to a DC power supply; The output end of the inverter circuit is connected to the input end of the AC filter circuit, the output end of the AC filter circuit is connected to the output end of the inverter, and the output end of the inverter is connected to an AC power supply.

3. The busbar capacitor structure of the inverter according to claim 2, characterized in that: The filtering circuit is a filtering capacitor; The input end of the inverter circuit is provided with a first filter capacitor; the output end of the switch circuit is provided with a second filter capacitor.

4. The busbar capacitor structure of the inverter according to claim 3, characterized in that: The first filter capacitor and the second filter capacitor are both arranged on the power board; The distance between the input end of the inverter circuit and the first filter capacitor on the power board does not exceed a preset distance; The distance between the output end of the switching circuit and the second filter capacitor on the power board does not exceed a preset distance.

5. The bus capacitor structure of the inverter according to claim 3, characterized in that: The first filter capacitor and the second filter capacitor are both connected in series with corresponding damping elements.

6. The busbar capacitor structure of the inverter according to claim 5, characterized in that: The number of the first filter capacitors is proportional to the number of bridge arms of the inverter circuit, and each of the first filter capacitors is connected in series with a corresponding damping element.

7. The busbar capacitor structure of the inverter according to claim 6, characterized in that: The number of the first filter capacitors is the same as the number of bridge arms of the inverter circuit; When the inverter circuit has two bridge arms, the number of the first filter capacitors is two.

8. The busbar capacitor structure of the inverter according to claim 5, characterized in that: The filter capacitor is a thin film capacitor; The damping element is a magnetic bead.

9. The busbar capacitor structure of the inverter according to any one of claims 2 to 8, characterized in that: The bracket is a plurality of conductive metal pillars, and the plurality of metal pillars include a first metal pillar and a second metal pillar; The first metal column is connected to the input end of the inverter circuit and the output end of the capacitor group; The second metal column is connected to the output end of the switch circuit and the input end of the capacitor group.

10. An inverter, characterized in that: The invention comprises a power board, an inverter circuit and a switch circuit arranged on the power board, and a bus capacitor structure according to any one of claims 1 to 9.

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