Power conversion device

Abstract

To provide a power conversion device with reduced inductance.SOLUTION: A power conversion device includes: a plurality of smoothing capacitors configured to smooth a DC voltage; a first bus bar member including a first positive electrode bus bar and a first negative electrode bus bar connected to the plurality of smoothing capacitors and a first insulating material provided between the first positive electrode bus bar and the first negative electrode bus bar; a plurality of semiconductor devices configured to convert a DC voltage to an AC voltage; and a second bus bar member having a second positive electrode bus bar and a second negative electrode bus bar connected to the plurality of semiconductor devices and a second insulating material provided between the second positive electrode bus bar and the second negative electrode bus bar. The first bus bar member is formed by stacking the first positive electrode bus bar and the first negative electrode bus bar, and has a first connection unit for connecting to the second bus bar member. The second bus bar member is formed by stacking the second positive electrode bus bar and the second negative electrode bus bar, and has a second connection unit connected to the first connection unit. The first connection unit has a projection unit projecting toward the second connection unit.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a power conversion device. [Background technology]

[0002] In the field of inverter development, the use of SiC (Silicon Carbide) for switching elements has become mainstream. This increases the switching frequency and surge voltage, which increases the possibility of the switching elements being damaged and generates noise. Therefore, it is necessary to reduce the inductance in inverters. For example, Patent Document 1 listed below discloses a configuration for reducing inductance in which bus bars connected to DC capacitors are stacked and directly connected to a power module. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6824840 Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the configuration described in Patent Document 1, an object of the present invention is to provide a power conversion device that further reduces inductance. [Means for solving the problem]

[0005] The power conversion device 100 includes a first bus bar member having a plurality of smoothing capacitors that smooth a DC voltage, a first positive bus bar and a first negative bus bar connected to the plurality of smoothing capacitors, and a first insulating material provided between the first positive bus bar and the first negative bus bar; and a second bus bar member having a plurality of semiconductor devices that convert the DC voltage into an AC voltage, a second positive bus bar and a second negative bus bar connected to the plurality of semiconductor devices, and a second insulating material provided between the second positive bus bar and the second negative bus bar, wherein the first bus bar member is formed by stacking the first positive bus bar and the first negative bus bar and has a first connection portion for connecting to the second bus bar member, and the second bus bar member is formed by stacking the second positive bus bar and the second negative bus bar and has a second connection portion connected to the first connection portion, and the first connection portion has a protrusion that protrudes toward the second connection portion. [Effects of the Invention]

[0006] A power conversion device that achieves reduced inductance can be provided. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is an overall perspective view illustrating a configuration of a power conversion device according to an embodiment of the present invention; [Figure 2] Enlarged front view of Figure 1A [Figure 3] B-B' cross section of Figure 2 [Figure 4] 10A and 10B are diagrams illustrating third and fourth connection portions according to an embodiment of the present invention. [Figure 5] FIG. 4 is a structural diagram illustrating a connecting portion according to one embodiment of the present invention (a cross-sectional view taken along the line CC′ in FIG. 4). [Figure 6] 1A and 1B are perspective and D-view diagrams of a gate bus bar according to an embodiment of the present invention; [Figure 7] 1 is a structural diagram of a molded bus bar from the perspective of a gate bus bar according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and some omissions and simplifications have been made as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0010] (One embodiment and overall configuration) (Figs. 1 to 4) The power conversion device 100 includes a semiconductor device 1, a smoothing capacitor 2, a molded bus bar 3, and a gate bus bar 4. The molded bus bar 3 (first bus bar member) has a first relay portion 10 formed between the plurality of smoothing capacitors 2. Similarly, the gate bus bar 4 (second bus bar member) has a second relay portion 10a formed between the plurality of semiconductor devices 1. The first relay portion 10 and the second relay portion 10a are fastened to each other by a fastening member (not shown), thereby electrically connecting them.

[0011] The plurality of smoothing capacitors 2 smoothes the DC voltage input from a battery (not shown) to the semiconductor device 1. The plurality of semiconductor devices 1 convert the smoothed DC voltage into an AC voltage and output it to a motor (not shown).

[0012] The first relay portion 10 and the second relay portion 10a each have a U-shaped cross section. The molded bus bar 3 is a laminated bus bar formed by stacking a first positive bus bar 3a and a first negative bus bar 3b, and is electrically connected to the smoothing capacitor 2. A molded bus bar insulating material 30 (first insulating material) is provided between the first positive bus bar 3a and the first negative bus bar 3b. The gate bus bar 4 is a laminated bus bar formed by stacking a second positive bus bar 4a and a second negative bus bar 4b, and is electrically connected to the semiconductor device 1. A gate bus bar insulating material 40 (second insulating material) is provided between the second positive bus bar 4a and the second negative bus bar 4b.

[0013] In the molded bus bar 3, the first relay portion 10 has a first connection portion 5 formed by the first positive bus bar 3a or the first negative bus bar 3b. In the gate bus bar 4, the second relay portion 10a has a second connection portion 6 formed by the second positive bus bar 4a or the second negative bus bar 4b. The first connection portion 5 and the second connection portion 6 each have a connection portion through-hole 21. The first connection portion 5 has a protrusion 5a that protrudes toward the second connection portion 6. Note that FIG. 3 illustrates an example in which the protrusion 5a is formed by the first positive bus bar 3a.

[0014] The first relay section 10 also has a third connection section 8. The third connection section 8 is bent from the first connection section 5 and faces the smoothing capacitor 2. The second relay section 10a also has a fourth connection section 9. The fourth connection section 9 is bent from the second connection section 6 and faces the semiconductor device 1.

[0015] The connection portion through-holes 21 of the first connection portion 5 and the connection portion through-holes 21 of the second connection portion 6 overlap with each other, and a fastening member (not shown) is inserted into the overlapping connection portion through-holes 21 to fasten the first relay portion 10 and the second relay portion 10a to each other. As a result, the first connection portion 5 and the second connection portion 6 are electrically connected to each other, and the molded bus bar 3 and the gate bus bar 4 are electrically connected and fastened to each other.

[0016] By fastening the protrusion 5a of the first connection portion 5 and the second connection portion 6 to each other, a connecting portion 20 is formed in which a portion of the first positive bus bar 3a and a portion of the first negative bus bar are stacked along the extension direction of the first connection portion 5. The structure of the connecting portion 20 will be described later.

[0017] (Figure 5) A plurality of coupling portions 20 are formed along the extension direction of the first connection portion 5, and are portions where at least a portion of the first positive bus bar 3a and at least a portion of the first negative bus bar 3b are stacked one on top of the other with the molded bus bar insulating material 30 interposed therebetween. In addition, fastening portions 22 are provided between the plurality of coupling portions 20, respectively, to fasten the molded bus bar 3, which is the first bus bar member, and the gate bus bar 4, which is the second bus bar member, to each other. Each fastening portion 22 has a connection portion through-hole 21.

[0018] In the present invention, the formation of the connecting portion 20 increases the stacking range of the first positive bus bar 3a and the second positive bus bar 4a compared to the conventional case. Furthermore, the formation of the space 3c between the fastening portion 22 and the third connection portion 8 allows the first positive bus bar current 11 and the first negative bus bar current 12 to flow between the third connection portion 8 and the first connection portion 5, and the connecting portion 20 forms a limited current path in which the first positive bus bar current 11 and the first negative bus bar current 12 flow in opposite directions and overlap. This increases the density of the currents and increases the coupling coefficient between the positive bus bar and the negative bus bar, thereby improving the inductance reduction effect compared to the conventional case.

[0019] (Fig. 6, Fig. 7) In the gate bus bar 4, the gate bus bar insulating material 40 is formed so as to surround the second connection portion 6. In the molded bus bar 3, the molded bus bar insulating material 30, which is the first insulating material, is formed so as to surround the periphery of the protrusion 5a of the first connection portion 5.

[0020] By doing so, the area of ​​the second negative electrode bus bar 4b formed around the second connection portion 6 that connects to the protrusion 5a can be increased compared to conventional cases while ensuring insulation, thereby reducing self-inductance.

[0021] As described above, the present invention can increase the area in which the positive and negative bus bars are stacked, even in a structure in which the number of locations where the bus bars can be stacked is limited, such as in the relay sections 10 and 10a, which have a configuration that can be connected to multiple semiconductor devices 1 arranged separately and in which the connection area between the molded bus bar 3 and the gate bus bar 4 is small. This increases mutual inductance and reduces inductance. Furthermore, increasing the area in which the bus bars are stacked contributes to the realization of a more compact power conversion device 100 and a larger current capacity.

[0022] According to the embodiment of the present invention described above, the following advantageous effects are achieved.

[0023] (1) The power conversion device 100 includes a first bus bar member 3 having a plurality of smoothing capacitors 2 that smooth a DC voltage, a first positive bus bar 3a and a first negative bus bar 3b that are connected to the plurality of smoothing capacitors 2, and a first insulating material 30 that is provided between the first positive bus bar 3a and the first negative bus bar 3b, a plurality of semiconductor devices 1 that convert a DC voltage into an AC voltage, a second positive bus bar 4a and a second negative bus bar 4b that are connected to the plurality of semiconductor devices 1, and an insulating material 30 that is provided between the second positive bus bar 4a and the second negative bus bar 4b. and a second bus bar member 4 having a second insulating material 40 provided between the first bus bar member 3 and the first negative bus bar member 4b, the first bus bar member 3 being formed by stacking a first positive bus bar 3a and a first negative bus bar 3b, and having a first connection portion 5 for connecting to the second bus bar member 4, the second bus bar member 4 being formed by stacking a second positive bus bar 4a and a second negative bus bar 4b, and having a second connection portion 6 connected to the first connection portion 5, the first connection portion 5 having a protrusion 5a protruding toward the second connection portion 6. In this way, it is possible to provide a power conversion device 100 that achieves reduced inductance and miniaturization.

[0024] (2) The first bus bar member 3 has first relay portions 10 formed between the plurality of smoothing capacitors 2, the second bus bar member 4 has second relay portions 10a formed between the plurality of semiconductor devices 1 and connected to the first relay portions 10, the first relay portions 10 have a first connection portion 5 and a third connection portion 8 bent from the first connection portion 5 and facing the smoothing capacitor 2, the second relay portion 10a has a second connection portion 6 and a fourth connection portion 9 bent from the second connection portion 6 and facing the semiconductor device 1, and the first relay portions 10 and the second relay portions 10a each have a U-shaped cross section. In this way, even if the area that can be stacked is limited, it is possible to form a laminated bus bar and reduce inductance.

[0025] (3) At least a portion of the first positive bus bar 3a and at least a portion of the first negative bus bar 3b are stacked on top of each other, and a plurality of coupling portions 20 are formed along the direction in which the first connection portion 5 extends, and fastening portions 22 are provided between the plurality of coupling portions 20 to fasten the first bus bar member 3 and the second bus bar member 4 to each other. This increases the coupling coefficient between the positive bus bar and the negative bus bar, thereby reducing inductance.

[0026] (4) The first insulating material 30 is formed so as to surround the periphery of the protruding portion 5a, thereby reducing the self-inductance.

[0027] The present invention is not limited to the above-described embodiments, and various modifications and combinations of other configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-described embodiments, and includes those in which some of the configurations are omitted. [Explanation of symbols]

[0028] 1. Semiconductor device 2 smoothing capacitors 3 Molded busbar 3a 1st positive bus bar 3b First negative bus bar 3c space 4 Gate bus bar 4a Second positive bus bar 4b Second negative bus bar 5 First connection part 5a Protrusion 6 Second connection part 8 Third connection part 9 Fourth connection part 10 First relay section 10a Second relay section 11 First positive bus bar current 12 First negative bus bar current 20 Connection part 21 Connection through hole 22 Fastening part 30 Molded busbar insulation material 40 Gate bus bar insulation 100 Power conversion device

Claims

1. a plurality of smoothing capacitors for smoothing the DC voltage; a first bus bar member including a first positive bus bar and a first negative bus bar connected to the plurality of smoothing capacitors, and a first insulating material provided between the first positive bus bar and the first negative bus bar; a plurality of semiconductor devices that convert the DC voltage into an AC voltage; a second bus bar member including a second positive bus bar and a second negative bus bar connected to the plurality of semiconductor devices, and a second insulating material provided between the second positive bus bar and the second negative bus bar, the first bus bar member is formed by stacking the first positive bus bar and the first negative bus bar, and has a first connection portion for connecting to the second bus bar member, the second bus bar member is formed by stacking the second positive bus bar and the second negative bus bar, and has a second connection portion connected to the first connection portion, The first connection portion has a protrusion that protrudes toward the second connection portion. Power conversion device.

2. the first bus bar member has a first relay portion formed between the plurality of smoothing capacitors, the second bus bar member has a second relay portion formed between the plurality of semiconductor devices and connected to the first relay portion, the first relay section has the first connection section and a third connection section that is bent from the first connection section and faces the smoothing capacitor, the second relay portion has the second connection portion and a fourth connection portion that is bent from the second connection portion and faces the semiconductor device, The first link portion and the second link portion each have a U-shaped cross section. The power conversion device according to claim 1 .

3. at least a portion of the first positive bus bar and at least a portion of the first negative bus bar are stacked on top of each other, and a plurality of coupling portions are formed along an extending direction of the first connection portion, Fastening portions for fastening the first bus bar member and the second bus bar member to each other are provided between the plurality of connecting portions. The power conversion device according to claim 1 .

4. The first insulating material is formed to surround the periphery of the protrusion. The power conversion device according to claim 1 .

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