JPH06315265A - Cooling structure of power converter - Google Patents

Abstract

PURPOSE:To suppress temperature rise variation among smiconductor elements fitted to a vertically long heat radiating fin by uniformly cooling the semiconductor elements. CONSTITUTION:This structure comprises an elongated heat radiator with fins 3, fitted with a plurality of semiconductor elements 4; an elongated air duct 7 defined partly by the finned side of the heat radiator; and a fan 5 for introducing air into the duct 7 from one side. The radiator is made in an inclined state so that the air passing cross-sectional area of the duct 7 can become smaller toward one end from the other end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for a power converter in which a plurality of semiconductor elements are attached to a vertically long heat dissipation fin.

[0002]

2. Description of the Related Art There is a power converter in which a plurality of power semiconductor elements are attached to a single heat dissipation fin to reduce the size thereof. As this type of power converter, there is a cooling structure shown in FIG. In FIG. 2, (a) is a front view with the door opened, (b)
Is a sectional view taken along the line A-A, and (c) is a sectional view taken along the line BB. This power converter is housed in a space closed by a box 1 and a door 2. The heat dissipation fin 3 has a flat shape on one surface and a fin for heat dissipation on the other surface, and has a vertically long shape. The semiconductor elements 4a to 4e of the insulated power module are attached to the flat surface of the heat dissipation fin 3. Further, the fin side of the heat dissipation fin 3 is used as a part of the inner wall, and the wind tunnel 7 is provided between the box body 1 and the partition wall 6.
Is formed, and the cooling fan 5 blows air from below.

Further, when the pressure loss in the wind tunnel becomes large, the amount of air by the cooling fan 5 decreases and the heat radiation effect decreases, so a small gap is provided between the fin of the heat radiation fin 3 and the box body 1.

[0004]

However, in such a conventional cooling structure, it is customary to dispose the heat dissipation fins 3 vertically so that the upper semiconductor element is arranged to dissipate heat from the lower semiconductor element. Under the influence of the influence, the temperature rise of the semiconductor element increases as it goes upward as shown by the characteristic A of FIG. However, the power loss of the elements is assumed to be equal. In this case, the rated capacity of the power converter must be determined by the temperature rise θ _A of the uppermost semiconductor element 4e.

Further, in order to reduce the above-mentioned difference in temperature rise, a ventilation guide 8 is provided at an appropriate position in the wind tunnel, and FIG.
As shown in (b), the wind W passing through the gap that does not contribute to cooling is guided toward the heat dissipation fin 3 from the middle. In this case, the temperature rise of each element depends on the characteristic B of FIG.
As shown in, the position of the element that changes and the maximum temperature rise changes. In this figure, the maximum temperature rise of the semiconductor element 4c is θ _B
Is an example. However, in this case as well, there was variation in the temperature rise between the elements, and it was not possible to efficiently energize all the elements.

The present invention has been made in order to solve the above problems, and an object of the present invention is to cool a plurality of semiconductor elements mounted on a vertically long heat dissipation fin in a well-balanced manner to eliminate variations in temperature rise. It is to provide a cooling structure for a power converter.

[0007]

In order to achieve the above-mentioned object, the present invention provides a vertically elongated heat radiation fin to which a plurality of semiconductor elements are attached, and the fin side of the heat radiation fin as a part of an inner wall of a box body. And a fan that sends wind from one side into the wind tunnel, and the longitudinal direction of the heat dissipation fin is inclined so that the ventilation cross-sectional area of the wind tunnel becomes smaller from one side to the other side. Then install.

[0008]

With the above structure, the wind blown from one side of the wind tunnel by the fan is dispersed and blown into the inclined heat radiation fins, and only a part of the wind contributes to cooling to one of the heat radiation fins. As the air flow cross-sectional area becomes smaller toward the other side of the wind tunnel, other winds also gradually contribute to cooling, and the temperature of the other semiconductor element is suppressed from being affected by heat radiation of one semiconductor element, and all semiconductors Makes the temperature rise of the element uniform.

[0009]

FIG. 1 shows an embodiment of the present invention. In FIG. 1, (a) is a front view in which a door is opened, (b) is an AA sectional view, (c) is a BB sectional view, and (d) is a CC sectional view. This power converter is housed in a space closed by a box 1 and a door 2. The heat dissipation fin 3 has a flat shape on one surface and a fin for heat dissipation on the other surface, and has a vertically long shape. The semiconductor elements 4a to 4e of the insulated power module are attached to the flat surface of the heat dissipation fin 3. Further, a wind tunnel 7 is formed between the box body 1 and the partition wall 6 with the fin side of the heat dissipation fin 3 as a part of the inner wall, and the air is blown from below by the cooling fan 5.

In this case, as shown in FIG. 1 (b), the wind tunnel 7
The cross-sectional area of the air flow is the air outlet (the upper part of the box 1 in the figure)
The heat radiation fins 3 are attached so as to be inclined in the longitudinal direction so that the heat radiation fins 3 become gradually narrower. Therefore, the cross-sectional area of ventilation is wide as shown in the CC sectional view of FIG. 1 (d), and narrow as shown in the BB sectional view of FIG. 1 (c). .

With the above structure, the air blown into the wind tunnel by the cooling fan 5 is dispersed and blown into the inclined heat radiation fins 3 as shown in FIG. Only W ₁ contributes to cooling, and the other winds W _{2 to} W ₄ gradually contribute to cooling toward the upper part. As a result, the temperature rise of the upper semiconductor element is suppressed by the heat radiation of the lower semiconductor element, as shown in FIG.
As indicated by the characteristic C in (1), the temperature can be uniformly increased, and the maximum temperature increase θ _C can be reduced. Therefore, all the semiconductor elements can be efficiently energized, and the rated capacity of the power conversion device can be increased. Further, a snubber circuit component (capacitor, resistor, etc.) 9 for suppressing a surge voltage is attached to each semiconductor element 4, but since the heat dissipation fin 3 is inclined, FIG.
As shown in (a), the upper snubber article is not affected by the heat radiation of all the lower snubber articles and becomes high temperature, and the reliability is improved.

[0012]

According to the present invention, a plurality of semiconductor elements mounted on a vertically long heat dissipation fin are cooled in a well-balanced manner,
It is possible to provide a cooling structure for a power conversion device that can eliminate variations in temperature rise, can efficiently energize each semiconductor element, and can increase the rated capacity.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment according to the present invention.

FIG. 2 is a configuration diagram of a conventional power conversion device.

3A and 3B are views for explaining the operation of the present invention and the conventional apparatus, FIG. 3A is the present invention, FIG. 3B is an operational view of the conventional apparatus, and FIG.
Is the temperature characteristic diagram of both

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Box body 2 ... Door 3 ... Heat radiation fin 4 ... Semiconductor element 5 ... Cooling fan 6 ... Partition wall 7 ... Wind tunnel 9 ... Snubber circuit article

Claims (2)

[Claims] 1. A vertically long heat dissipation fin to which a plurality of semiconductor elements are attached, a vertically long wind tunnel provided in the box body with the fin side of the heat dissipation fin as a part of an inner wall, and a wind from one side in the wind tunnel. And a fan for feeding the heat radiation fins, and the cooling structure of the power conversion device is installed such that the longitudinal direction of the heat dissipation fins is inclined so that the ventilation cross-sectional area of the wind tunnel decreases from one side to the other side. 2. The cooling structure for a power conversion device according to claim 1, wherein the wind tunnel is configured such that a part of the heat dissipation fin and a part of the box body are formed as inner walls. Construction.