Capacitor Cooling Structure and Power Conversion Device

Abstract

To reduce a size and cost of a device having a smoothing capacitor by efficiently cooling the smoothing capacitor without requiring an additional component.SOLUTION: A cell unit 1 includes: a case 10 to which cooling air C is supplied and in which a plurality of smoothing capacitors 3 of a high-voltage inverter board 2 are erected side by side in a flow direction of the cooling air C; and an insulation sheet 6 that is provided in an opening 11 of the case 10 so as to face one end of the plurality of smoothing capacitors 3 to insulate among conductors P, PN, and N connecting the plurality of smoothing capacitors 3 and a semiconductor component 4 of the high-voltage inverter board 2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cooling structure for a smoothing capacitor applied to a power conversion device such as a high-voltage inverter unit.

Background Art

[0002] A capacitor bank including a plurality of smoothing capacitors applied to a high-voltage inverter unit cools the smoothing capacitors by supplying cooling air to the plurality of smoothing capacitors arranged upwind of a heat sink (Patent Document 1). Further, a guide member for guiding the cooling air flowing in the vicinity of the inner surface of the capacitor bank corresponding to the space between the adjacent smoothing capacitors along the flow direction of the cooling air is provided on the inner surface of the capacitor bank. Thereby, the cooling air is evenly supplied to the plurality of smoothing capacitors, and uniform cooling of the plurality of smoothing capacitors becomes possible.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A conventional capacitor cooling structure such as that of Patent Document 1 requires at least a guide member as an additional part, leading to an increase in cost.

[0005] In view of the above circumstances, an object of the present invention is to efficiently cool a smoothing capacitor without requiring additional parts, and to reduce the size and cost of a device including the smoothing capacitor.

Means for Solving the Problems

[0006] Therefore, one aspect of the present invention is a capacitor cooling structure having a case in which cooling air is supplied and a plurality of smoothing capacitors of a power conversion device are erected side by side in the flow direction of the cooling air, and an insulating sheet provided at an opening of the case facing one end side of the plurality of smoothing capacitors for insulating between conductors connecting the smoothing capacitors and semiconductor components of the power conversion device.

[0007] One aspect of the present invention is that in the capacitor cooling structure, intake holes for the cooling air are formed in a part of the insulating sheet on the leeward side of the cooling air.

[0008] One aspect of the present invention is that in the capacitor cooling structure, the smoothing capacitor on the leeward side of the cooling air is arranged at a position obliquely in the flow direction of the cooling air from the smoothing capacitor on the windward side of the cooling air.

[0009] One aspect of the present invention is a power conversion device having the above capacitor cooling structure.

Advantages of the Invention

[0010] According to the present invention as described above, the smoothing capacitor can be efficiently cooled without requiring additional parts, so that the size reduction and cost reduction of the device equipped with the smoothing capacitor can be achieved.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Best Mode for Carrying Out the Invention

[0012] Embodiments of the present invention will be described below with reference to the drawings.

[0013] [Embodiment 1] A cell unit 1, which is an aspect of the capacitor cooling structure of the present invention shown in FIG. 1, is provided in a high-voltage inverter board 2 of FIG. 2, which is an aspect of a power conversion device.

[0014] The high-voltage inverter board 2 is formed by stacking a plurality of cell units 1 each equipped with a single-phase inverter in series and in multiple layers in the height direction of the high-voltage inverter board 2. An intake port 21 for cooling air C is provided in the front portion 20 of the high-voltage inverter board 2. Further, an exhaust fan 23 for discharging the cooling air C supplied for cooling the cell unit 1 is installed in the ceiling portion 22 of the high-voltage inverter board 2. And a duct 24 to which the cooling air C discharged from each individual cell unit 1 is supplied is secured on the rear side (downstream side) of the cell unit 1 within the high-voltage inverter board 2.

[0015] The cell unit 1 has a case 10 in which cooling air C is supplied and a plurality of smoothing capacitors 3 of the single-phase inverter are erected side by side in the flow direction of the cooling air C. A semiconductor component 4 composed of a power semiconductor element of the single-phase inverter is arranged at a position behind the smoothing capacitor 3 on the most downstream side of the cooling air C within the case 10. In particular, the semiconductor component 4 is arranged on a heat sink 5 arranged at the position on the rear side.

[0016] Also, an insulating sheet 6 that insulates between conductors P, PN, and N connecting the smoothing capacitor 3 and the semiconductor component 4 is disposed in the opening 11 of the case 10 facing one end side (upper end side) of the smoothing capacitor 3. The conductor PN connects the smoothing capacitors 3 in two parallel rows and three series rows, for example, as shown in FIG. 1. The conductor P connects the P - pole side of the smoothing capacitor 3 that is in parallel on the most upstream side of the cooling air C among the two - parallel - three - series smoothing capacitors 3 to the P - pole side of the semiconductor component 4. The conductor N connects the N - pole side of the smoothing capacitor 3 that is in parallel on the most downstream side of the cooling air C among the two - parallel - three - series smoothing capacitors 3 to the N - pole side of the semiconductor component 4.

[0017] The operation and effect of Embodiment 1 will be described with reference to FIGS. 1 to 3.

[0018] When the exhaust fan 23 of the high - voltage inverter board 2 operates, as shown in FIG. 3, outside air is supplied into the case 10 as cooling air C through the intake port 21 of the front part 20 and further through the intake port 12 of the case 10. The cooling air C introduced into the case 10 migrates to the duct 24 of the high - voltage inverter board 2 in FIG. 2. In the process of this migration, a plurality of smoothing capacitors 3 in the case 10 are sequentially used for cooling from the upstream - side smoothing capacitor 3. The cooling air C that has passed through the smoothing capacitor 3 is further used for cooling the semiconductor component 4 and the heat sink 5 in FIG. 3, and then is supplied to the duct 24 in FIG. 2 through the exhaust port 13 of the case 10. Then, the cooling air C that has migrated from each cell unit 1 in the high - voltage inverter board 2 merges in the duct 24 and is discharged from the ceiling part 22 of the high - voltage inverter board 2 by the exhaust fan 23.

[0019] According to the cell unit 1, since the insulating sheet 6 that insulates between the conductors P, PN, and N in FIG. 1 faces one end side (upper end side) of the smoothing capacitor 3 and is disposed in the opening 11 of the case 10, one end of the smoothing capacitor 3 is covered by the insulating sheet 6, and a wind tunnel that functions as a cooling guide is formed. Therefore, the wind speed of the cooling air C around the smoothing capacitor 3 is increased, and the cooling effect of the smoothing capacitor 3 is enhanced compared with the case without the cooling guide. Also, since the heat sink 5 of the semiconductor component 4 is disposed on the downstream side of the smoothing capacitor 3, the semiconductor component 4 can be cooled.

[0020] According to the above cell unit 1, an insulating sheet 6 is provided to cover the plurality of one - end sides of the plurality of smoothing capacitors 3 so that the cooling air C does not escape from the one - end sides of the plurality of smoothing capacitors 3, thereby obtaining a cooling effect for the plurality of smoothing capacitors 3. In particular, since the insulating sheet 6 that insulates between the conductors P, PN, and N also functions as a cooling guide for the smoothing capacitor 3, the smoothing capacitor 3 can be efficiently cooled without requiring additional components. Therefore, the size reduction and cost reduction of the device equipped with the smoothing capacitor 3 can be achieved.

[0021] [Embodiment 2] In the cell unit 1 of Embodiment 2 illustrated in FIG. 4, in the insulating sheet 6, an intake hole 61 for the cooling air C is formed at a site on the leeward side of the cooling air C. The intake hole 61 is particularly formed at a site on the leeward side and near the inner surface of the case 10 in the insulating sheet 6.

[0022] Inside the case 10, due to the heat generation of the smoothing capacitor 3 on the windward side of the cooling air C, the ambient temperature around the smoothing capacitor 3 increases as the cooling air C goes leeward, and the cooling effect of the smoothing capacitor 3 may decrease. In contrast, according to Embodiment 2, since the cooling air C is introduced from the intake hole 61, the cooling air C from the smoothing capacitor 3 on the windward side and the cooling air C from the outside (outside air) of the cell unit 1 are mixed, and the ambient temperature of the smoothing capacitor 3 on the leeward side can be reduced. Thereby, the decrease in the cooling effect of the smoothing capacitor 3 on the leeward side is alleviated, and a uniform cooling effect for the smoothing capacitors 3 on the windward side and the leeward side in the case 10 can be obtained.

[0023] Therefore, according to the cell unit 1 of Embodiment 2, since the ambient temperature of the smoothing capacitor 3 on the leeward side can be reduced, in addition to the effect of Embodiment 1, the cooling effect of the smoothing capacitor 3 on the leeward side is improved.

[0024] [Embodiment 3] In the cell unit 1 illustrated in FIG. 5, the smoothing capacitor 3 on the leeward side of the cooling air C is arranged at a position obliquely in the flow direction of the cooling air C from the smoothing capacitor 3 on the windward side of the cooling air C.

[0025] According to the cell unit 1 of the above-described Embodiment 3, compared with Embodiment 1, the arrangement space of the smoothing capacitor 3 increases. However, the contact efficiency between the smoothing capacitor 3 on the leeward side of the cooling air C and the cooling air C is increased as compared with Embodiment 1, and the cooling effect is improved. Further, by using the insulating sheet 6 of Embodiment 2 in combination, the cooling effect is further improved.

Explanation of Signs

[0026] 1... cell unit, 10... case, 11... opening, 12... intake port, 13... exhaust port 2... high-voltage inverter board, 20... front part, 21... intake port, 22... ceiling part, 23... exhaust fan, 24... duct 3... smoothing capacitor 4... semiconductor component 5... heat sink 6... insulating sheet, 61... intake hole C... cooling air P, PN, N... conductors

Claims

1. A case in which cooling air sucked by an exhaust fan of a power conversion device is supplied, and a plurality of smoothing capacitors of the power conversion device are erected side by side in the flow direction of the cooling air; An insulating sheet provided at an opening of the case so as to cover one ends of the plurality of smoothing capacitors, and insulating between conductors connecting the smoothing capacitors and semiconductor components of the power conversion device; comprising: In the insulating sheet, in a region outside the center line along the flow direction passing through the center of the upper end of the smoothing capacitor closest to the inner surface of the case on the leeward side of the cooling air and inside the inner surface, an intake hole capable of introducing the cooling air sucked by the exhaust fan is formed. A capacitor cooling structure characterized by the above.

2. The capacitor cooling structure according to claim 1, wherein the smoothing capacitor on the leeward side of the cooling air is arranged at an oblique position in the flow direction of the cooling air from the smoothing capacitor on the windward side of the cooling air.

3. A power conversion device, characterized by having the capacitor cooling structure according to claim 1 or 2.

Images