Power conversion device

Abstract

Provided is a power conversion device. The embodiment of the utility model relates to a power conversion device using a forced air cooling mode. The utility model provides a power conversion device, which can enable a semiconductor element on a downwind side not to be influenced by heat of a semiconductor element on an upwind side so as to improve cooling efficiency, prevent temperature difference between the semiconductor elements on the upwind side and the downwind side, and restrain performance reduction of peripheral elements. In a power conversion device having a semiconductor element and a heat sink for cooling the semiconductor element, the heat sink has a heat receiving plate on which the semiconductor element is disposed, and a first fin group and a second fin group vertically provided on one surface of the heat receiving plate on which the semiconductor element is disposed. The height of the fins of the first fin group is lower than the height of the fins of the second fin group.

Description

[0001] This application is based on Japanese Patent Application 2024-011694, filed on January 30, 2024, and claims priority to that application. The entire contents of that application are incorporated herein by reference. Technical Field

[0002] The embodiments of this utility model relate to a power conversion device using forced air cooling. Background Technology

[0003] Generally, power conversion devices for elevators consist of semiconductor elements, coolers for cooling the semiconductor elements, and other electrical components. Here, the semiconductor elements of the power conversion device are equipped with heat sinks for cooling. It is important to efficiently dissipate the heat from the semiconductor elements into these heat sinks and then exhaust it to the outside air via a cooling fan.

[0004] As coolers, they can be broadly categorized into forced circulation liquid cooling using pumps, forced air cooling using cooling fans or blowers, and natural air cooling using only radiators. When selecting these cooling methods, considerations are made based on cooling performance, cost reduction, noise reduction, energy saving, and maintenance-free operation. However, when the load on semiconductor components increases to a certain level, natural air cooling becomes insufficient. Therefore, forced air cooling is mostly chosen for power conversion systems used in elevators. In particular, in forced air cooling systems for power conversion systems employing multiple semiconductor components, these components are arranged to transfer their heat to a radiator, and then the heat is dissipated using airflow generated by a cooling fan (FAN). Utility Model Content

[0005] However, in power conversion devices with a large number of semiconductor elements, the semiconductor elements on the downwind side are affected by the heat of the semiconductor elements on the upwind side. Therefore, under the same load on the semiconductor elements, the temperature of the semiconductor elements rises more as you move downwind. Furthermore, there is a temperature difference between the semiconductor elements on the upwind and downwind sides. The semiconductor elements with greater temperature rise are more susceptible to damage (reduced reliability).

[0006] The present invention is proposed in view of the above circumstances, and its objective is to provide a power conversion device that can reduce the thermal impact of heat from the semiconductor element on the downwind side to the semiconductor element on the upwind side, improve cooling efficiency, and prevent temperature differences from easily occurring between the semiconductor elements on the upwind and downwind sides, thereby preventing damage to the semiconductor elements due to temperature rise.

[0007] To address the aforementioned problems, one embodiment of the power conversion device includes a semiconductor element and a heat sink for cooling the semiconductor element. The heat sink has a heat-receiving plate in contact with the semiconductor element, and a first fin group and a second fin group erected on one side of the heat-receiving plate in contact with the semiconductor element. Here, the height of the fins in the first fin group is lower than the height of the fins in the second fin group. Therefore, the height of the fins on the leeward side is higher than that on the upwind side, resulting in higher cooling performance and the ability to supply fresh air to the leeward side. This reduces the temperature difference between the semiconductor elements on the upwind and leeward sides, and reduces ventilation resistance by lowering the height of the fins on the upwind side. Thus, when multiple semiconductor elements are arranged and configured along the airflow direction, the temperature difference between the semiconductor elements on the upwind and leeward sides can be reduced, thereby preventing heat concentration and avoiding damage to the semiconductor elements due to temperature rise caused by concentrated heat, thus improving the reliability of the semiconductor elements. Attached Figure Description

[0008] Figure 1 This is a schematic perspective view of the cooling section (radiator) of a power conversion device used as a comparative example.

[0009] Figure 2 This is a perspective view of the power conversion device as described in the first embodiment.

[0010] Figure 3 This is a perspective view of the power conversion device according to the second embodiment.

[0011] Figure 4 This is a perspective view of the power conversion device as a modified example of the second embodiment.

[0012] Figure 5 This is a perspective view of the power conversion device as described in the third embodiment. Detailed Implementation

[0013] Hereinafter, various embodiments will be described with reference to the accompanying drawings. Furthermore, in the following embodiments, the same reference numerals will be used to denote the same constituent elements, and descriptions will be omitted.

[0014] (Specific issues envisioned for each implementation method)

[0015] First, the cooling section (radiator) of the power conversion device, which is a comparative example and is a prerequisite for this embodiment, will be described. Figure 1 This is a schematic perspective view of the cooling section (radiator) of a power conversion device used as a comparative example.

[0016] exist Figure 1The power conversion device includes: a semiconductor element 200 that rectifies input AC power into DC power and then converts the rectified DC power back into AC power; a heat sink 100 that cools the heat generated by the semiconductor element 200; a heat receiving plate (base plate) 600 that contacts the semiconductor element 200; a pipe structure 500 disposed on one side of the heat sink 100 and connecting the heat sink 100 and the cooling fan 300; and the cooling fan 300 disposed on the downwind side.

[0017] Here, the heat sink 100 has multiple fins, each fin being formed of a material with high heat dissipation performance, such as aluminum. Regarding cooling, cooling air for cooling the heat sink 100 is exhausted from the end of the heat sink 100 by a cooling fan 300 located at one end of the heat sink 100, dissipating heat passing between the multiple fins on the heat sink 100 to the outside, thereby cooling the semiconductor element 200. That is, the heat generated by the multiple semiconductor elements 200 is transferred to the heat sink 100 and dissipated 400 by the airflow generated by the cooling fan 300.

[0018] In recent years, miniaturization of semiconductor components 100 has been a trend in power conversion devices, driven by advancements in semiconductor device miniaturization. However, the heat generated by the semiconductor component 100 itself is not drastically reduced. Therefore, miniaturization of the package leads to further heat concentration, and the temperature rise caused by this concentrated heat becomes a major cause of damage to the semiconductor component 100.

[0019] The embodiments described below provide techniques for solving these problems. According to these techniques, cooling efficiency can be improved by reducing the thermal impact on the leeward semiconductor element from the upwind semiconductor element. This reduces the temperature difference between the upwind and leeward semiconductor elements. Therefore, heat is not concentrated, and damage to the semiconductor element 100 due to concentrated heat is prevented.

[0020] [First Implementation Method]

[0021] Figure 2 The figure shows a first embodiment, and the power conversion device of the first embodiment is described with reference to this figure.

[0022] Figure 2 This is a perspective view of the power conversion device as described in the first embodiment. Figure 2 The power conversion device has the following structure: multiple semiconductor elements 13 are arranged in the direction of airflow, and these semiconductor elements 13 are cooled by a fan 8 and a heat sink 15 having first and second comb-shaped fins 6 and 7.

[0023] In this specification, "upwind side" refers to the side of the radiator 15 furthest from the fan 8 along its length, and "downwind side" refers to the side of the radiator 15 closest to the fan 8 along its length. That is, referring to the accompanying drawings, the airflow from the fan 8 flows from the left to the right along the length of the radiator 15.

[0024] like Figure 2 As shown, the power conversion device includes: a semiconductor element 13, which rectifies the input AC power into DC power and then converts the rectified DC power back into AC power; a heat sink 15, which cools the heat generated by the semiconductor element 13; a heat receiving plate (base plate) 12, which has a first surface in contact with the semiconductor element 13; a leak-proof pipe structure 10, which is installed on the heat sink 15 to prevent air entering the heat sink 15 from leaking out of the heat sink 15 outlet; and a cooling fan 8, which is installed at one end of the heat sink 15. Furthermore, the heat sink 15 includes the heat receiving plate 12 in contact with the semiconductor element 13, a first comb-shaped fin (first fin group) 6, and a second comb-shaped fin (second fin group) 7, wherein the height of the fins of the first comb-shaped fin 6 is lower than the height of the fins of the second comb-shaped fin 7. Here, the first and second comb-shaped fins 6 and 7 are respectively composed of multiple fins erected on one surface of the heat receiving plate 12 in contact with the semiconductor element 13, forming the first and second fin groups. Furthermore, the end of the first comb-shaped fin 6, which is lower in height on the upwind side, is provided with a flow divider 9 to separate the wind entering the first comb-shaped fin 6 from the wind that does not pass through the first comb-shaped fin 6.

[0025] Here, the cooling fan 8 cools the semiconductor element 13 by dissipating heat between multiple fins disposed on the heat sink 15 to the outside. That is, the heat generated by the multiple semiconductor elements 13 is transferred to the heat sink 15, and the heat is dissipated 11 by the airflow generated by the cooling fan 8.

[0026] The heat sink 15 is a heat sink with a comb-shaped structure. On the back side (or second side, hereinafter sometimes referred to as the "base surface") of the heat-receiving plate 12 opposite the first side that contacts the semiconductor element 13, it has multiple plate-shaped fins for heat dissipation. The main surface of each fin is arranged approximately perpendicular to the base surface. Here, each fin is plate-shaped. Figure 2As shown, the first (low-height) and second (high-height) comb-shaped fins (first and second fin groups) 6 and 7 are each composed of multiple plate-shaped fins, which are arranged substantially parallel at predetermined intervals. That is, the multiple fins of each of the first and second comb-shaped fins 6 and 7 are arranged substantially parallel at predetermined intervals in a direction substantially orthogonal to the first base and the second base of the heat-receiving plate 12. Furthermore, the first base and the second base, which serve as the bases for the first and second comb-shaped fins (first and second fin groups) 6 and 7, have the same or substantially the same thickness. However, this invention is not limited to this. The thicknesses of the first base and the second base can be configured to be different.

[0027] like Figure 2 As shown, in the forced air cooling method of this embodiment, a plurality of semiconductor elements 13 are arranged in the direction of airflow, and these semiconductor elements 13 are cooled by a fan 8, a first comb-shaped fin 6 with a low fin height disposed on the upwind side, and a second comb-shaped fin 7 with a high fin height disposed on the downwind side. The heat generated by the semiconductor elements 13 is transferred to the first comb-shaped fin 6 and the second comb-shaped fin 7 through the heat-receiving plate 12, and is dissipated through the first comb-shaped fin 6 and the second comb-shaped fin 7.

[0028] In this embodiment of the radiator 15, the fins are characterized by having different heights on the upper and lower sides, with the fins on the lower side being taller than those on the upper side. Furthermore, since a diverter plate 9 is provided at the end of the lower-height fins on the upper side to separate the airflow entering the fins from the airflow not passing through them, the temperature difference between the components on the upper and lower sides can be reduced. Additionally, the presence of a pipe structure 10 acting as a leak-proof plate prevents airflow entering the radiator 15 from leaking out of the radiator 15 outlet, thus effectively dissipating heat from the air entering the radiator 15.

[0029] The heating plate 12 serves as the base for the first and second comb-shaped fins 6 and 7. The shape of this planar plate is not particularly limited; for example, it can be a round or elliptical shape, or a polygon such as a quadrilateral (rectangle, square), hexagon, or octagon.

[0030] [Effect of the first implementation method]

[0031] Next, the function of the forced air cooling method in the power conversion device of the first embodiment will be explained.

[0032] In a structure where multiple semiconductor elements 13 are arranged along the airflow direction, the semiconductor elements 13 in the lower part are affected by the heat of the semiconductor elements 13 in the upper part. Under the same load on the semiconductor elements 13, the temperature of the semiconductor elements 13 in the lower part increases significantly, creating a temperature difference between the semiconductor elements 13 in the lower and upper parts. In contrast, by employing the structure of the heat sink 15 of the power conversion device of this embodiment, a first (low-height) comb-shaped fin 6 with a low fin height is arranged on the upper side, and a second (high-height) comb-shaped fin 7 with a high fin height is arranged on the lower part. Therefore, the cooling performance of the fins on the lower side is improved compared to the upper side, and fresh air unaffected by the heat from the first comb-shaped fin 6 on the upper side can be supplied to the second comb-shaped fin 7 on the lower side. Thus, the temperature of the semiconductor elements on the lower side can be reduced. Furthermore, a pipe structure 10 is provided as a leak-proof plate, preventing air entering the heat sink 15 from leaking out of the heat sink 15 outlet. This allows for effective heat dissipation 11 from the air entering the heat sink 15.

[0033] [Effects of the First Embodiment]

[0034] According to the power conversion device of this embodiment described above, since the fins on the leeward side are taller than those on the upwind side, their cooling performance is superior, allowing fresh air to be supplied to the leeward side. Therefore, the temperature difference between the semiconductor elements on the upwind and leeward sides can be reduced, and by lowering the height of the fins on the upwind side, ventilation resistance can be reduced. Thus, when multiple semiconductor elements are arranged in a configuration along the airflow direction, the temperature difference between the semiconductor elements on the upwind and leeward sides can be reduced, thereby preventing heat concentration and avoiding damage to the semiconductor elements due to temperature rise caused by concentrated heat, thus improving the reliability of the semiconductor elements.

[0035] Furthermore, while this embodiment describes the heat dissipation fins as having a comb-shaped structure, the present invention is not limited to this. For example, the heat dissipation fins can be a pin-fin structure where each fin is pin-shaped, or they can have other shapes. That is, as long as the fan air can be exhausted from the upper airflow side to the lower airflow side of the radiator, the fin structure can be arbitrary. When the structure of multiple fins is a pin-fin structure, each pin-fin extends in a direction perpendicular to the base surface. The multiple pin-fins are arranged at intervals along a first direction along the base surface and a second direction perpendicular to the first direction. The multiple pin-fins can be arranged in an alternating staggered pattern (chrysanthemum pattern) in the first direction, and the pin-fins can also be arranged according to a prescribed rule. This structure can also achieve the same effect as this embodiment.

[0036] [Second Implementation]

[0037] Figure 3This is a perspective view of the power conversion device according to the second embodiment. This embodiment differs from the first embodiment in that it includes two heat sinks arranged opposite each other with the airflow direction as the center. That is, in this embodiment, the fin height of the heat sink 15 is... Figure 2 Unlike the upwind and downwind sides, the radiator 15, with its fins on the downwind side being taller than those on the upwind side, is arranged relative to each other with the airflow direction as the center. This structure increases the area of ​​the heat-receiving portion of the radiator 15, thereby increasing the number of coolable semiconductor elements 15. Furthermore, in this embodiment, a turbulence-promoting plate 6, which promotes airflow turbulence, is provided on a portion of the step between the lower first comb-shaped fin 6 on the upwind side and the higher second comb-shaped fin 7 on the downwind side.

[0038] The forced air cooling method of the power conversion device in this embodiment is the same as that in the first embodiment. Multiple semiconductor elements 13 are arranged in the direction of airflow, and these semiconductor elements 13 are cooled by a fan 8, a first comb-shaped fin 6 with a low fin height arranged opposite to the upwind side, and a second comb-shaped fin 7 with a high fin height arranged opposite to the downwind side. Heat generated by the semiconductor elements 13 is transferred through a heat-receiving plate 12 to the first comb-shaped fin 6 and the second comb-shaped fin 7, and dissipated via the first comb-shaped fin 6 and the second comb-shaped fin 7. Here, a diverter plate 9 is provided at the end of the first comb-shaped fin 6 to separate the airflow entering the first comb-shaped fin 6 from the airflow not passing through the first comb-shaped fin 6, and a pipe structure 10 is provided to prevent the airflow entering the radiator 15 from leaking outside the outlet of the radiator 15.

[0039] [The Role of the Second Embodiment]

[0040] Next, the function of the forced air cooling method in the power conversion device of the second embodiment will be explained.

[0041] In the power conversion device of this embodiment, since the first comb-shaped fins 6 and the second comb-shaped fins 7 are respectively arranged opposite to each other, the area of ​​the heat-receiving part can be doubled. In addition, by arranging the first comb-shaped fins 6 with a low fin height on the upwind side and the second comb-shaped fins 7 with a high fin height on the downwind side, the downwind side can have higher fin cooling performance than the upwind side. Furthermore, since a splitter plate 9 is provided at the end of the first comb-shaped fins 6 to separate the air entering the first comb-shaped fins 6 from the air that does not pass through the first comb-shaped fins 6, fresh air that is not affected by the heat from the first comb-shaped fins 6 on the upwind side can be supplied to the second comb-shaped fins 7 on the downwind side, thereby reducing the temperature of the semiconductor element 13 on the downwind side.

[0042] [Effects of the Second Implementation]

[0043] The power conversion device according to this embodiment, as described above, has the same effects as the power conversion device of the first embodiment. Furthermore, compared to the power conversion device of the first embodiment, the power conversion device of this embodiment can increase the area of ​​the heated portion of the heat sink 15 and increase the number of cooled semiconductor elements 13. Therefore, when cooling the same number of semiconductor elements 13, the planar area of ​​the semiconductor elements 13 can be halved. Furthermore, compared to the power conversion device of the first embodiment, since a turbulence-promoting plate 14 that promotes airflow is provided on a portion of the step between the first comb-shaped fin 6 on the upwind side and the second comb-shaped fin 7 on the downwind side, the airflow entering the second comb-shaped fin 7 on the downwind side can be turbulentized, improving the cooling efficiency of the fins. Thus, when multiple semiconductor elements 13 are arranged along the airflow direction, by eliminating the problem of temperature differences between the semiconductor elements on the upwind and downwind sides, damage to the semiconductor elements 13 caused by temperature rise due to heat can be prevented, thereby improving the reliability of the semiconductor elements.

[0044] Furthermore, while this embodiment describes the heat dissipation fins as having a comb-shaped structure, the present invention is not limited to this. That is, as long as the fan air can be exhausted from the upper airflow side of the heatsink to the lower airflow side, the fin structure can be arbitrary. For example, as... Figure 4 As shown, the heat dissipation fins can be pin fin structures or other shapes. When the multiple fins are pin fin structures, each pin fin extends along a direction perpendicular to the base surface. The multiple pin fins are spaced apart in a first direction along the base surface and a second direction perpendicular to the first direction. The multiple pin fins can be arranged in an alternating staggered pattern (like a houndstooth pattern) in the first direction, and the pin fins can also be arranged according to a predetermined rule. In this structure, the same effect as in this embodiment can be obtained.

[0045] [Third Implementation Method]

[0046] Figure 5 This is a perspective view of the power conversion device according to the third embodiment. Figure 3 Compared to the power conversion device of this embodiment, Figure 5 The difference in the power conversion device is that a heat pipe 17 is provided on the heat receiving plate 12 of the radiator 15. At this time, the heat pipe 17 is arranged so that the direction of the airflow flowing in the radiator 15 is the length direction of the heat pipe 17.

[0047] The forced air cooling method of the power conversion device in this embodiment is the same as that in the power conversion device of the above embodiment. Multiple semiconductor elements 13 are arranged in the direction of airflow. These semiconductor elements 13 are cooled by a fan 8, a first comb-shaped fin 6 with a low fin height arranged opposite to the windward side, a second comb-shaped fin 7 with a high fin height arranged opposite to the leeward side, and heat pipes 17 provided on the heat-receiving plate 12. The heat generated by the semiconductor elements 13 is transferred to the first comb-shaped fin 6 and the second comb-shaped fin 7 through the heat-receiving plate 12 and the heat pipes 17 provided on the heat-receiving plate 12, and is dissipated through the first comb-shaped fin 6 and the second comb-shaped fin 7. Here, a flow divider 9 is provided at the end of the first comb-shaped fin 6 to separate the airflow entering the first comb-shaped fin 6 from the airflow not passing through the first comb-shaped fin 6. A turbulence-promoting plate 14 is provided on a portion of the step between the first comb-shaped fin 6 on the windward side and the second comb-shaped fin 7 on the leeward side to promote turbulence in the airflow. In addition, the duct structure 10 is configured in such a way that the air entering the radiator 15 will not leak outside the outlet of the radiator 15. The heat pipe 17 is embedded in the heat-receiving plate 12, and the direction of the air flowing in the radiator 15 is the length direction of the heat pipe 17.

[0048] [The role of the third implementation method]

[0049] Next, the function of the forced air cooling method in the power conversion device of the third embodiment will be explained.

[0050] In the power conversion device of this embodiment, by arranging the first comb-shaped fins 6 and the second comb-shaped fins 7 opposite to each other, the area of ​​the heat-receiving part can be doubled. Furthermore, by arranging the first comb-shaped fins 6 with a lower fin height on the upwind side and the second comb-shaped fins 7 with a higher fin height on the downwind side, the fin cooling performance on the downwind side can be improved compared to the upwind side. Moreover, since a flow divider 9 is provided at the end of the first comb-shaped fins 6 to separate the airflow entering the first comb-shaped fins 6 from the airflow not passing through the first comb-shaped fins 6, fresh air unaffected by the heat from the first comb-shaped fins 6 on the downwind side can be supplied to the second comb-shaped fins 7, thereby reducing the temperature of the semiconductor element on the downwind side. Additionally, since a turbulence-promoting plate 14 is provided on a portion of the step between the first comb-shaped fins 6 and the second comb-shaped fins 7 to promote airflow turbulence, the airflow entering the second comb-shaped fins 7 on the downwind side can be turbulentized, improving the fin cooling efficiency. Furthermore, since the heat pipe 17 is arranged on the heat plate 12 in a direction that is the length direction of the heat pipe 17, the heat plate 12 can be homogenized.

[0051] [Effects of the Third Implementation]

[0052] According to the power conversion device of this embodiment described above, the same effects as those of the power conversion device of the second embodiment can be obtained. Furthermore, compared to the second embodiment, by embedding heat pipes 17 in the heating plate 12 in a manner that the direction of the airflow in the heat sink 15 is the longitudinal direction, the heating plate 12 can be homogenized, reducing the temperature difference between the semiconductor elements 13 on the upper and lower sides. Thus, when multiple semiconductor elements 13 are arranged in a configuration along the airflow direction, by eliminating the problem of temperature difference between the semiconductor elements 13 on the upper and lower sides, damage to the semiconductor elements caused by heat-induced temperature rise can be prevented, thereby improving the reliability of the semiconductor elements.

[0053] While several embodiments of this utility model have been described, these embodiments are presented by way of example and are not intended to limit the scope of the utility model. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the design. These embodiments or variations thereof are included in the scope or spirit of the utility model, and are included in the scope of the utility model and its equivalents as set forth in the claims.

Claims

1. A power conversion device comprising a semiconductor element and a heat sink for cooling the semiconductor element, characterized in that, The heat sink has a heat-receiving plate in contact with the semiconductor element, and a first fin group and a second fin group erected on one side of the heat-receiving plate in contact with the semiconductor element. The height of the fins in the first fin group is lower than the height of the fins in the second fin group.

2. The power conversion device as described in claim 1, characterized in that, The first fin group is configured to be positioned further upwind than the second fin group.

3. The power conversion device as described in claim 1, characterized in that, At the end of the first fin group, a diverter is also provided to separate the airflow entering the fins of the first fin group from the airflow that does not pass through the fins of the first fin group.

4. The power conversion device as described in claim 1, characterized in that, It is also equipped with a duct structure to prevent the air entering the radiator from leaking out of the radiator outlet.

5. The power conversion device as described in claim 1, characterized in that, The first fin group and the second fin group extend in a direction that is approximately orthogonal to the first base and the second base on which each fin is erected, and the multiple fins are arranged approximately parallel at a predetermined interval.

6. The power conversion device as described in claim 5, characterized in that, The first base and the second base have approximately the same thickness.

7. The power conversion device as described in claim 5, characterized in that, Each fin is plate-shaped or pin-shaped.

8. The power conversion device as described in claim 1, characterized in that, The cooling fan is positioned on the downwind side.

9. The power conversion device as described in claim 1, characterized in that, The heat-receiving plate of the radiator has a heat pipe, which is configured such that the direction of the airflow in the radiator is the length direction of the heat pipe.

10. The power conversion device as claimed in claim 1, characterized in that, It has two radiators, which are arranged opposite each other with the direction of airflow as the center.

11. The power conversion device as described in claim 10, characterized in that, A turbulence-promoting plate that promotes turbulence and facilitates airflow is also provided on a portion of the step between the first fin group and the second fin group.

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