Semiconductor device

Abstract

In a direct water-cooled semiconductor device in which a surface of a base plate on the opposite side to a semiconductor element mounting surface is cooled by a refrigerant, a semiconductor device is provided in which flow path resistance of the refrigerant can be reduced and deformation of a sealing portion due to refrigerant pressure can be suppressed. A direct water-cooling semiconductor device in which a surface of a base plate on the opposite side from a semiconductor element mounting surface is cooled by a refrigerant, the semiconductor device being provided with: a base plate; a semiconductor module mounted on a first surface of the substrate; and needle-shaped fins and plate-shaped fins attached to a second surface of the base plate on the opposite side to the first surface, the length of the plate-shaped fins from the second surface being shorter than the length of the needle-shaped fins from the second surface.

Description

Technical Field

[0001] The present invention relates to the structure of semiconductor devices, and more particularly to a technique effective for applying to a power semiconductor module in which a plurality of power semiconductor elements are modularized. Background Art

[0002] As a control device for a driving motor of a railway vehicle, there is a device (converter) that converts the trolley wire voltage from alternating current to direct current or a device (inverter) that converts from direct current to alternating current using power semiconductor elements. Since the power semiconductor elements generate heat due to conversion losses, it is necessary to appropriately cool the power semiconductor elements to reduce the temperature rise. This cooling method is selected according to the load such as high-speed vehicle operation and commuter vehicle operation. In high-speed vehicles with a large load, a water cooling device that can efficiently cool may sometimes be used.

[0003] In the water cooling technology of a power semiconductor module equipped with a plurality of power semiconductor elements, conventionally, a radiator with heat dissipation fins is installed on the power semiconductor module via, for example, a thermal grease. The heat dissipation fins are generally cooled by being immersed in a cooling water flow path, which is an indirect water cooling method. However, compared with metal, the thermal conductivity of the thermal grease is low, so the thermal resistance becomes large, which hinders the suppression of temperature rise.

[0004] In contrast, a power semiconductor module using a direct water cooling method in which heat is transferred from the power semiconductor element to the cooling water without using thermal grease is known in order to ensure higher cooling capacity.

[0005] In this direct water cooling type power semiconductor module, a power semiconductor element is mounted via an insulating layer on one surface of a base plate, and heat dissipation fins are provided on the other surface. The direct water cooling type power semiconductor module is constructed to be fixed to a water channel forming body using bolts, screws, etc., and the opening of the water channel forming body is covered and blocked by the heat dissipation fin forming surface of the base plate. It is easy to directly cool the heat dissipation fin forming surface with cooling water, and has the advantage of being able to efficiently dissipate the heat generated by the power semiconductor element.

[0006] On the other hand, in order to increase the output of a high withstand voltage inverter such as a railway with a high system voltage, multi-parallel use of power semiconductor modules becomes important. Multi-parallel use of power semiconductor modules has the effect of reducing the current load of each power semiconductor module and suppressing the temperature rise of the power semiconductor element.

[0007] As the background art in this technical field, there is a technology such as the advantageous document 1. In Patent Document 1, the following is disclosed: "The cooling structure of a power semiconductor element includes a chip 31 mounted on a mounting surface, a cooling water passage 26 formed opposite to the mounting surface and through which cooling water for cooling the chip 31 flows, and fins 41 provided in the cooling water passage 26. The fins 41 have a flat fin portion 42 and a corrugated fin portion 43 disposed in different intervals on the path of the cooling water passage 26. The flat fin portion 42 is formed from a surface extending along the path of the cooling water passage 26 in the flow direction of the cooling water. The corrugated fin portion 43 has a surface extending along the path of the cooling water passage 26 in a direction crossing the flow direction of the cooling water. The corrugated fin portion 43 is provided in such a manner that the heat transfer coefficient with respect to the cooling water is larger than that of the flat fin portion 42." (Paragraph

[0007] etc. of Patent Document 1)

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-201181 Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] In the case of using the structure of the above Patent Document 1, since the flow path is separated by a plurality of flat fin portions 42 and corrugated fin portions 43, the flow path resistance becomes large, and the pressure loss of the entire flow path tends to become large.

[0013] In addition, in the structure of Patent Document 1, when the housing and the heat dissipation plate on the path of water-cooling heat dissipation of the heat generated by the power semiconductor element are thinned in order to reduce the thermal resistance, the deformation caused by the cooling water pressure loss of the housing and the heat dissipation plate becomes large. Therefore, when sealing for preventing leakage of the refrigerant for water cooling is performed by screw connection, the deformation is likely to become large in the sealing portion far from the screw connection portion, and there are problems such as the need to prevent water leakage.

[0014] Therefore, an object of the present invention is to provide a semiconductor device that can reduce the flow path resistance of the refrigerant and can suppress the deformation of the sealing portion caused by the refrigerant pressure in a semiconductor device using a direct water-cooling method in which the surface of the base plate on the side opposite to the semiconductor element mounting surface is cooled by the refrigerant.

[0015] Means for Solving the Problems

[0016] In order to solve the above problems, the present invention is a semiconductor device using a direct water cooling method in which a refrigerant cools the surface of a base plate on the side opposite to the surface on which semiconductor elements are mounted, and is characterized by comprising: a base plate; a semiconductor module mounted on a first surface of the base plate; and needle fins and plate fins mounted on a second surface of the base plate opposite to the first surface, wherein the length of the plate fins from the second surface is shorter than the length of the needle fins from the second surface.

[0017] Effects of the Invention

[0018] According to the present invention, in a semiconductor device using a direct water cooling method in which a refrigerant cools the surface of a base plate on the side opposite to the surface on which semiconductor elements are mounted, it is possible to provide a semiconductor device that reduces the flow path resistance of the refrigerant and suppresses deformation of the sealing portion caused by the refrigerant pressure.

[0019] Thereby, it is possible to suppress deformation of the sealing portion caused by the refrigerant pressure due to pressure loss, improve the water pressure resistance, and improve the reliability of the semiconductor device. In addition, since the water pressure resistance is improved, the thickness of the base plate can be reduced, and the cooling efficiency of the semiconductor elements can be improved.

[0020] The above-described problems, structures, and effects other than those will become clear from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a circuit diagram of a main power conversion device of a railway vehicle including the power semiconductor module of Embodiment 1 of the present invention.

[0022] Figure 2 is Figure 1 a circuit diagram of the converter 4.

[0023] Figure 3 is Figure 1 a circuit diagram of the inverter 5.

[0024] Figure 4 is Figure 1 a cooling system diagram of the main power conversion device 10.

[0025] Figure 5 is Figure 4 an external view of the power unit 53.

[0026] Figure 6 is Figure 5 a circuit diagram of the power semiconductor module 100.

[0027] Figure 7 is Figure 5 an external view of the power semiconductor module 100.

[0028] Figure 8A is Figure 7 a side view in the B-B direction of

[0029] Figure 8B is Figure 7 a side view in the C-C direction of

[0030] Figure 9 is Figure 5 an exploded view of the power semiconductor module 100 of

[0031] Figure 10 a top view of the base plate of the power semiconductor module according to Embodiment 1 of the present invention, as observed from the water channel forming body side.

[0032] Figure 11 is Figure 5 an exploded perspective view of the power unit 53 of

[0033] Figure 12 is a diagram showing Figure 5 the flow direction of the cooling water in the water channel forming body 70 of the power unit 53 of

[0034] Figure 13 is Figure 5 a sectional view taken along the A-A direction of

[0035] Figure 14 a top view of the base plate of the power semiconductor module according to Embodiment 2 of the present invention, as observed from the water channel forming body side.

[0036] Figure 15 is a side view of the power semiconductor module according to Embodiment 3 of the present invention.

[0037] Figure 16 is a top view of the base plate of the power semiconductor module according to Embodiment 4 of the present invention, as observed from the water channel forming body side.

[0038] Figure 17 is a top view of the base plate of the power semiconductor module according to Embodiment 5 of the present invention, as observed from the water channel forming body side.

[0039] Figure 18 is a top view of the base plate of the power semiconductor module according to Embodiment 6 of the present invention, as observed from the water channel forming body side.

[0040] Figure 19 is a sectional view of the power unit according to Embodiments 7 and 8 of the present invention.

[0041] Figure 20 is a top view of the base plate of the power semiconductor module according to Embodiment 9 of the present invention, as observed from the water channel forming body side.

[0042] Figure 21This is a top view of the base plate of the power semiconductor module according to Embodiment 10 of the present invention, as observed from the side of the water passage forming body. Detailed Description of the Invention

[0043] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each drawing, the same reference numerals are assigned to the same structures, and detailed descriptions of overlapping parts are omitted.

[0044] Embodiment 1

[0045] Refer to Figures 1 to 13 to describe the power semiconductor module according to Embodiment 1 of the present invention.

[0046] Figure 1 This is a circuit diagram of the main power conversion device 10 of a railway vehicle equipped with the power semiconductor module of this embodiment. The power semiconductor module of this embodiment is an example in which the present invention is applied to a power semiconductor module using a direct water cooling method mounted on a power conversion device.

[0047] As Figure 1 shown, the AC power supplied from the trolley wire 1 is converted into DC power by the converter 4 which is a rectifier circuit. After being rectified by the converter 4 constituting the main power conversion device 10, the DC power smoothed by the smoothing capacitor 3 is applied to the inverter 5 and inversely converted into AC power of a desired voltage and frequency. After the inverse conversion, the three-phase AC power output by the inverter 5 is output to the AC motor 6 to drive the AC motor 6 at a desired rotational speed.

[0048] Figure 2 This is a circuit diagram of the converter 4 constituting the main power conversion device 10. As Figure 2 shown, the converter 4 converts the AC power from the trolley wire 1 into DC power. The input AC power is supplied to the AC wiring 40r, 40s of the converter 4, and is rectified using the upper switching elements 31 and rectifying elements 33, and the lower switching elements 32 and rectifying elements 34 provided in each phase.

[0049] In this embodiment, IGBT (Insulated Gate Bipolar Transistor) is used as the switching element and a diode is used as the rectifying element, but it is not limited thereto, and other types of elements can also be applied. The switching elements 31, 32 of the converter 4 are driven by the drive signal 210 from the control circuit 200.

[0050] Figure 3 This is a circuit diagram of the inverter 5 constituting the main power conversion device 10. As Figure 3As shown, the inverter 5 converts the DC power smoothed by the smoothing capacitor 3 into three-phase AC power. The DC power converted by the converter 4 is converted into three-phase AC power using the upper switching element 31 and rectifying element 33, and the lower switching element 32 and rectifying element 34 provided for each phase, and output to the AC power lines 40u, 40v, and 40w. The switching elements 31 and 32 of the inverter 5 are driven by the drive signal 211 from the control circuit 201.

[0051] In the converter 4 and the inverter 5, the power semiconductor modules carrying the switching elements 31, 32 and the rectifying elements 33, 34 generate heat during this power conversion operation, and the temperature rises. To suppress this temperature rise, a cooling device is installed on the power semiconductor module for cooling.

[0052] Figure 4 It is a cooling system diagram of the cooling device 20 for cooling the converter 4 and the inverter 5. The cooling system of the cooling device 20 in this embodiment removes the heat generated by the power semiconductor module 100 through the circulating cooling water, so that the main power conversion device 10 operates stably. It is advisable to use a refrigerant such as water or an ethylene glycol aqueous solution for the cooling water, but other liquids can also be used.

[0053] In this embodiment, a structure is shown in which the power unit 53 composed of four parallel-connected power semiconductor modules 100 is cooled in three parallel connections. The number of parallel-connected power semiconductor modules 100 or the number of parallel-connected power units 53 can also be changed according to the rated output. In addition, parallel or series connections can be set arbitrarily.

[0054] As Figure 4 shown, the low-temperature cooling water 51 (liquid refrigerant) ejected from the pump 50 is distributed to each power unit 53 through the low-temperature side distribution pipe 52. The distributed low-temperature cooling water 51 removes the heat generated by the power semiconductor module 100 on each power unit 53 and becomes the high-temperature cooling water 54 with a rising water temperature. After the high-temperature cooling water 54 is discharged from the power unit 53, it is collected by the high-temperature side distribution pipe 55 and transported to the radiator 56.

[0055] Through the heat exchange between the high-temperature cooling water 54 in the radiator 56 and the cooling air 58 introduced by the fan 57, it becomes the low-temperature cooling water 51 with a decreasing water temperature. The volume change of the cooling water due to the temperature change in the cooling system is absorbed by the expansion tank 59. The low-temperature cooling water 51 discharged from the radiator 56 is transported by the pump 50 and circulated in the cooling system.

[0056] Figure 5 It is an external view of the power unit 53. As Figure 5 shown, the power unit 53 is composed of four parallel-connected power semiconductor modules 100 and a water channel forming body 70.

[0057] Figure 6 is the circuit diagram of the power semiconductor module 100 used in this embodiment. As Figure 6 shown, the power semiconductor module 100 includes switching elements 31, 32 and rectifying elements 33, 34 mounted on an insulating substrate. Between each power semiconductor element, they are connected in a way that forms Figure 2 , Figure 3 the branch 35 shown. In addition, a positive DC terminal 110p, a negative DC terminal 110n, an AC terminal 110ac, and a gate terminal 110g for controlling the on and off of the switching element are mounted on the insulating substrate.

[0058] Figure 7 is the external view of the power semiconductor module 100 used in this embodiment. As Figure 7 shown, the external contour of the power semiconductor module 100 is composed of a base plate (substrate plate) 130 that dissipates the heat of the internal power semiconductor element 101 (the symbol 101 described later Figure 9 ) to the cooling water, and a case 113 that protects the power semiconductor element 101 and the insulating substrate 102 (the symbol 102 described later Figure 9 ).

[0059] As Figure 9 described later, the power semiconductor module 100 includes a plurality of power semiconductor elements 101, an insulating substrate 102, and a single base plate 130. The power semiconductor module 100 mounts the power semiconductor element 101 on one surface of the insulating substrate 102, and the other surface of the insulating substrate 102 is joined to the surface of the base plate 130. The other surface of the base plate 130 constitutes the bottom surface of the power semiconductor module 100, and has a structure that directly contacts the low-temperature cooling water 51 (liquid refrigerant) for cooling.

[0060] Since the base plate 130 has the function of dissipating the heat of the power semiconductor element 101 to the cooling water, the thermal conductivity of the material is greater than 100 W / mK. For example, copper (Cu), aluminum (Al), AlSiC, MgSiC, etc. are considered.

[0061] The base plate 130 is provided with fixing through holes 114 for fixing to the water channel forming body 70.

[0062] The case 113 is formed of a resin material such as polyphenylene sulfide resin. A positive DC terminal 110p and a negative DC terminal 110n are provided on one side of the power semiconductor module 100, and an AC terminal 110ac is provided on the side opposite to the side where the DC terminals 110p, 110n are arranged. In addition to the high-voltage system terminals (DC terminals 110p, 110n and AC terminal 110ac), low-voltage system terminals (gate terminal 110g and low-voltage system electrode 111) are also provided.

[0063] Figure 8A and Figure 8B is a side view of the power semiconductor module 100, Figure 8A is Figure 7 a side view in the B - B direction of Figure 8B indicating a side view in the C - C direction.

[0064] As Figure 8A and Figure 8B shown, on the surface where the base plate 130 abuts against the water channel forming body 70 (the surface having the sealing portion 135), a plurality of (for example, a total of about 100 or more) minute columnar needle - shaped fins (heat dissipation fins) 131 as protrusions are prominently provided. In addition, there are two flat fins (plate - shaped fins) 132 extending in the long - side direction so as to sandwich the area of the needle - shaped fins 131.

[0065] The height (length) of the flat fin 132 from the base plate 130 is lower (shorter) than the height (length) of the needle - shaped fin 131 from the base plate 130. In addition, the height of the flat fin 132 from the base plate 130 is uniform.

[0066] Figure 9 is an exploded view of the power semiconductor module 100, shown as Figure 8B an exploded view of Figure 9 As shown, the insulating substrate 102 on which the power semiconductor element 101 is mounted is joined to the base plate 130 via a bonding material (not shown).

[0067] Figure 10 is a top view of the base plate 130 of the power semiconductor module 100 as viewed from the water channel forming body 70 side, that is, a top view of the heat dissipation fin forming surface of the base plate 130.

[0068] On the base plate 130, a plurality of columnar needle - shaped fins 131 and a pair of flat fins 132 extending in the long - side direction of the power semiconductor module 100 are formed. In addition, there is a sealing portion 135 shown by a dotted line. This dotted - line portion is contacted by an O - ring (reference numeral 73 of Figure 11 described later) to prevent leakage of cooling water. In addition, the area of the needle - shaped fins 131 is sandwiched by the main surfaces of the flat fins 132.

[0069] The circular needle - shaped fins 131 may also be formed to protrude from the base plate 130 by forging. In addition, other needle - shaped components may be joined to the base plate 130 by soldering or the like. Similarly, the flat fins 132 may also be formed to protrude from the base plate 130 by forging.

[0070] In addition, it is also possible to use, for example, soldering or the like to join a flat plate made differently from the base plate 130 to the base plate 130.

[0071] Figure 11 is Figure 5 exploded perspective view of the power unit 53. As Figure 11 shown, the power unit 53 is configured by arranging the power semiconductor module 100 via an O-ring 73 in such a manner as to block the opening 75 located on the upper surface of the water channel forming body 70, inserting bolts through the bolt holes 76 for fixing the power semiconductor module, and fixing the power semiconductor module 100 to the water channel forming body 70. In the present embodiment, an O-ring 73 is used as the sealing member, but other seals may also be used. By mounting the O-ring 73 and the power semiconductor module 100 from the upper surface, the O-ring 73 does not shift from the O-ring groove 74 during assembly, improving the assemblability.

[0072] Figure 12 is a view showing the flow direction of the cooling water in the water channel forming body 70. As Figure 12 shown, the low-temperature cooling water 51 flows into the water channel forming body 70 from the low-temperature side cooling water joint 71. The cooling water 60 (liquid refrigerant) in the water channel forming body flows in the space formed by the opening 75, the pin fins 131 of the base plate 130, and the flat fins 132 (the space sandwiched by the covered side walls), directly cooling the base plate 130. The cooling water 60 rises in temperature through heat exchange in the pin fins 131 and the flat fins 132 and becomes the high-temperature cooling water 54 discharged from the high-temperature side cooling water joint 72.

[0073] As Figure 12 shown, the flow paths of the low-temperature side cooling water joint 71 at the inlet and the high-temperature side cooling water joint 72 at the outlet of the water channel forming body 70 are narrow. On the other hand, the width of the inter-module flow path 77 flowing between adjacent power semiconductor modules 100 is approximately the same as the long side of the opening 75.

[0074] In addition, in Figure 11 and Figure 12 the structure shown, the main surface of the flat fin 132 is perpendicular to the flow direction of the cooling water 60 (liquid refrigerant).

[0075] Figure 13 is Figure 5 A - A cross-sectional view of. As Figure 13 shown, the flow path of the cooling water 60 passes under the flat fin 132, then passes through the area of the pin fins 131 and passes under the flat fin 132 again to connect to the inter-module flow path 77, and becomes deeper in the inter-module flow path 77 than in the area of the pin fins 131. As described above, the height of the flat fin 132 from the base plate 130 is lower than that of the pin fins 131.

[0076] The effects of the structure of the present embodiment described above will be described.

[0077] As shown Figure 13 in FIG. [not provided], the effect that the height of the flat fin 132 from the base plate 130 is lower than that of the pin fin 131 will be described.

[0078] The cooling water 60 that enters the power unit 53 through the water passage forming body 70 passes under the flat fin 132 that is lower than the pin fin 131, and will not be subject to a flow path resistance greater than necessary, and the increase in pressure loss can be suppressed to the minimum. In addition, even when passing through the area of the power semiconductor module 100, the cooling water 60 also passes under the flat fin 132 that is lower than the pin fin 131, but the increase in pressure loss can also be suppressed to the minimum.

[0079] As shown Figure 10 in FIG. [not provided], the effect that the flat fin 132 extending in the long side direction of the base plate 130 is located near the sealing portion 135 will be described.

[0080] Due to the pressure loss generated by the cooling water circulation, the base plate 130 is pushed by the cooling water 60, and the base plate 130 deflects to the side opposite to the extending direction of the pin fin 131. Although the threaded connection portions at the four corners (the portions of the fixing through holes 114) do not deform in the base plate 130, the deformation is the largest between the connection portions. If the surrounding sealing portion 135 exceeds the deformation threshold, it is considered that water leakage will occur. Generally, compared with the short side of the base plate 130, the deflection of the long side of the base plate 130 is larger, so water leakage is likely to occur due to a low pressure loss on the long side.

[0081] In this embodiment, by the flat fin 132 being located near the sealing portion 135 on the long side of the base plate 130, the deformation on the long side of the base plate 130 caused by the pressure loss is suppressed, so the water pressure resistance can be improved.

[0082] As described above, according to the power semiconductor module of this embodiment, by arranging the flat fin 132 extending in the long side direction of the base plate 130 near the sealing portion, even if the base plate 130 is thinner than before, the water pressure resistance can be ensured. Therefore, the base plate 130 can be made thinner, the heat dissipation channel of the power semiconductor element can be shortened, and the thermal resistance can be reduced. In addition, the flat fin 132 itself also functions as a fin for heat dissipation, so the heat dissipation performance can also be improved.

[0083] Embodiment 2

[0084] Refer to Figure 14 FIG. [not provided] to describe the power semiconductor module of Embodiment 2 of the present invention. Figure 14 is a top view of the base plate 130 of the power semiconductor module 100 as viewed from the side of the water passage forming body 70, that is, a top view of the heat dissipation fin forming surface of the base plate 130.

[0085] As Figure 14 shown, the difference of the power semiconductor module 100 of this embodiment from that of Embodiment 1 ( Figure 10 ) lies in that the flat fins 132 extending in the short side direction of the base plate 130 are arranged on the short side of the area of the pin fins 131. In addition, the direction of the cooling water flow changes from the short side direction to the long side direction of the power semiconductor module 100. In addition, in order to form a power unit, the power semiconductor module 100 is rotated 90 degrees in the arrangement direction so that the short side directions of the power semiconductor modules 100 are adjacent to form a water channel forming body 70. Other structures are the same as those of Embodiment 1 ( Figure 10 ).

[0086] The effects of the structure of this embodiment will be described.

[0087] The effect that the height of the flat fins 132 from the base plate 130 is lower than that of the pin fins 131 will be described.

[0088] Similar to the content described in Embodiment 1 ( Figure 13 ), since the cooling water 60 entering the power unit 53 through the water channel forming body 70 passes under the flat fins 132 which are lower than the pin fins 131, it will not be subject to a flow path resistance greater than necessary, and the increase in pressure loss can be suppressed to the minimum. In addition, when passing through the area of the power semiconductor module 100, although the cooling water 60 also passes under the flat fins 132 which are lower than the pin fins 131, the increase in pressure loss can also be suppressed to the minimum.

[0089] The effect that the flat fins 132 extending in the short side direction of the base plate 130 are located near the sealing portion 135 will be described.

[0090] Due to the pressure loss generated in the cooling water circulation, the flexure of the base plate 130 is larger on the long side of the base plate 130 than on the short side, so the water pressure resistance becomes lower. However, when a constraint for suppressing the deformation of the long side is applied to the power semiconductor module 100, the place where water leakage is likely to occur next becomes the short side of the base plate 130. By strengthening the vicinity of the sealing portion on the short side of the base plate 130 with the flat fins 132 extending in the short side direction, the deformation of the short side of the base plate 130 can be suppressed, so the water pressure resistance can be improved.

[0091] In the power semiconductor module according to this embodiment, by disposing the flat fins 132 extending in the short side direction of the base plate 130 near the sealing portion, even if the base plate 130 is made thinner than before, the water pressure resistance can be ensured. Therefore, the base plate 130 can be made thinner, the channel for heat dissipation of the power semiconductor element can be shortened, and the thermal resistance can be reduced. In addition, since the flat fins 132 themselves also function as fins for heat dissipation, the heat dissipation performance can be improved.

[0092] Embodiment 3

[0093] Refer to Figure 15 , and the power semiconductor module of Embodiment 3 of the present invention will be described. Figure 15 is a side view of the power semiconductor module 100 of this embodiment, corresponding to the side view in the C-C direction of Figure 7 .

[0094] The difference from Embodiment 1( Figure 8B ) is that the height of the flat fins 132 extending in the long side direction of the power semiconductor module 100 is uneven from the base plate 130, and becomes the highest near the midpoint between the connection points of the power semiconductor module 100.

[0095] Regarding the structure in which at least one of the two flat fins 132 has a high midpoint, the other can be a flat fin with a uniform height. Other structures are the same as those in Embodiment 1( Figure 8B ).

[0096] The effects of the structure of this embodiment will be described.

[0097] The influence of the flow of the cooling water 60 caused by the height of the flat fins 132 from the base plate 130 being lower (that is, thinner) than that of the pin fins 131 on the cooling performance is the same as that in Embodiment 1. In addition, the effect that the flat fins 132 extending in the long side direction of the power semiconductor module 100 (base plate 130) are located near the sealing portion is also the same as that in Embodiment 1.

[0098] As Figure 15 shown, the effect that the height of the flat fins 132 is the highest at the center in the long side direction of the power semiconductor module 100 will be described.

[0099] The cooling water 60 entering from the low-temperature side cooling water joint 71 reaches near the center in the long side direction of the power semiconductor module 100. In the region where only the pin fins 131 are present, the cooling water 60 does not only flow short-circuit near the center of the power semiconductor module 100, but rather flows uniformly to some extent, but the flow through the central vicinity is slightly more.

[0100] When the height near the center of the flat fin 132 on the low-temperature side cooling water joint 71 side of the power semiconductor module 100 near the low-temperature side cooling water joint 71 is the highest, the short-circuit flow of the cooling water 60 in the center of the power semiconductor module 100 is suppressed to a certain extent. Accordingly, the flow is divided into left and right and approaches a uniform flow. Therefore, within the power semiconductor module 100, the deviation in the cooling performance of multiple chips becomes smaller.

[0101] As Figure 15 shown, the influence on the water pressure resistance caused by the highest height of the flat fin 132 in the center in the long side direction of the power semiconductor module 100 will be described.

[0102] Since the flat fin 132 with a uniform height is located near the sealing portion in the long side direction and the deflection of the long side of the base plate 130 caused by the pressure loss is suppressed, it has the effect of improving the water pressure resistance. However, as in this embodiment, in the center of the long side where it is most likely to deflect, the flat plate becomes the highest, that is, the thickest. Thus, in the center of the long side, the deflection of the base plate 130 is further suppressed and the water pressure resistance is further improved.

[0103] As Figure 15 shown, the influence on the cooling performance caused by the highest height of the flat fin 132 in the center in the long side direction of the power semiconductor module 100 will be described.

[0104] By disposing the flat fin 132 extending in the long side direction of the power semiconductor module 100 near the sealing portion, even if the base plate 130 is made thinner compared to the past, the water pressure resistance can be ensured. However, by making the flat fin 132 higher (that is, thicker) in the center of the long side where the base plate 130 is likely to deflect, the water pressure resistance can be further improved. Thereby, the base plate 130 can be made thinner further, the heat dissipation path of the power semiconductor element can be shortened, and the thermal resistance can be reduced.

[0105] Embodiment 4

[0106] Refer to Figure 16 , and the power semiconductor module of Embodiment 4 of the present invention will be described. Figure 16 is a top view of the base plate 130 of the power semiconductor module 100 as observed from the side of the water channel forming body 70, that is, a top view of the heat dissipation fin forming surface of the base plate 130.

[0107] The different aspect from Embodiment 1 ( Figure 10 ) is that among the two plate-like fins 132 extending in the long side direction of the base plate 130, one is not a flat plate but is bent (has a buckling portion).

[0108] In addition, the height of the plate-shaped fin 132 from the base plate 130 is uniform. Additionally, although an example is shown in which the bent plate-shaped fin 132 is composed of a straight portion and a bent portion, it may also have a structure including a curve. Other structures are the same as those in Embodiment 1 ( Figure 10 )

[0109] The effects of the structure of this embodiment will be described.

[0110] The influence of the flow of the cooling water 60 caused by the fact that the height of the plate-shaped fin 132 from the base plate 130 is lower (i.e., thinner) than that of the needle-shaped fin 131 on the cooling performance is the same as that in Embodiment 1. Additionally, the effect that the plate-shaped fin 132 extending in the longitudinal direction of the base plate 130 is located near the sealing portion 135 is also the same as that in Embodiment 1.

[0111] The effect of bending the plate-shaped fin 132 extending in the longitudinal direction of the base plate 130 will be described.

[0112] Although a flat fin having a uniform width in the direction along the short side of the base plate 130 and linearly extending in the longitudinal direction also has the effect of suppressing the deformation of the base plate 130 at the center in the longitudinal direction, by bending the plate-shaped fin 132 into a zigzag shape, the effective width in the direction along the short side of the base plate 130 increases, and compared with Embodiment 1 ( Figure 10 )

[0113] the effect of suppressing the deformation of the base plate 130 at the center in the longitudinal direction increases. That is, the effect of improving the water pressure resistance increases.

[0114] Embodiment 5

[0115] Refer to Figure 17 to describe the power semiconductor module of Embodiment 5 of the present invention. Figure 17 is a top view of the base plate 130 of the power semiconductor module 100 as viewed from the side of the water channel forming body 70, that is, a top view of the heat dissipation fin forming surface of the base plate 130.

[0116] The differences from Embodiment 1 ( Figure 10 ) and Embodiment 2 ( Figure 14 ) are as follows. There are both two flat fins 132 extending in the longitudinal direction of the base plate 130 and two flat fins 132 extending in the short side direction of the base plate 130. Additionally, the flat fins 132 are not connected to each other. Other structures are the same as those in Embodiment 1 ( Figure 10 ) and Embodiment 2 ( Figure 14 )

[0117] The effects of the structure of this embodiment will be described.

[0118] The influence on the flow of the cooling water 60 caused by the fact that the flat fins 132 extending in the long side direction of the base plate 130 are lower (i.e., thinner) than the needle fins 131 from the base plate 130 is the same as that in Embodiment 1. In addition, the influence of the flow of the cooling water 60 caused by the fact that the flat fins 132 extending in the short side direction of the base plate 130 are lower (i.e., thinner) than the needle fins 131 from the base plate 130 on the cooling performance is the same as that in Embodiment 2.

[0119] In this embodiment, it is also possible to increase the water pressure resistance on the long side by having the flat fins 132 extending in the long side direction of the base plate 130 near the sealing portion 135. In addition, it is possible to increase the water pressure resistance on the short side by having the flat fins 132 extending in the short side direction of the base plate 130 near the sealing portion 135.

[0120] Since the water pressure resistance on both the long side and the short side of the base plate 130 is increased, the base plate 130 can be made thinner, the heat dissipation path of the power semiconductor element can be shortened, and the thermal resistance can be reduced.

[0121] Embodiment 6

[0122] Refer to Figure 18 , and the power semiconductor module of Embodiment 6 of the present invention will be described. Figure 18 It is a plan view of the base plate 130 of the power semiconductor module 100 as viewed from the side of the water channel forming body 70, that is, a plan view of the heat dissipation fin forming surface of the base plate 130.

[0123] The different aspects from Embodiment 5 ( Figure 17 ) are as follows. There are two flat fins 132 extending in the long side direction of the base plate 130 and two flat fins 132 extending in the short side direction of the base plate 130, and the flat fins 132 are connected to each other. That is, the flat fins 132 are arranged so as to surround the area of the needle fins 131. Other structures are the same as those in Embodiment 5 ( Figure 17 ).

[0124] The effects of the structure of this embodiment will be described.

[0125] The influence on the flow of the cooling water 60 caused by the fact that the flat fins 132 extending in the long side direction of the base plate 130 are lower (i.e., thinner) than the needle fins 131 from the base plate 130 is the same as that in Embodiment 1. In addition, the influence of the flow of the cooling water 60 caused by the fact that the flat fins 132 extending in the short side direction of the base plate 130 are lower (i.e., thinner) than the needle fins 131 from the base plate 130 on the cooling performance is the same as that in Embodiment 2.

[0126] In this embodiment, the flat fins 132 extending in the long side direction of the base plate 130 are located near the sealing portion 135, so that the water pressure resistance on the long side can be improved. In addition, the flat fins 132 extending in the short side direction of the base plate 130 are located near the sealing portion 135, so that the water pressure resistance on the short side can be improved. Further, by connecting the flat fins 132 extending in the long side direction and the short side direction to each other, the rigidity of the base plate 130 is further improved, and the water pressure resistance becomes further higher.

[0127] The water pressure resistance on both the long side and the short side of the base plate 130 is further improved compared with that in Embodiment 5. Therefore, the base plate 130 can be made thinner, the channel for heat dissipation of the power semiconductor element can be shortened, and the thermal resistance can be reduced.

[0128] Embodiment 7

[0129] Refer to Figure 19 , and the power semiconductor module according to Embodiment 7 of the present invention will be described. Figure 19 is a cross-sectional view of the power unit of this embodiment, corresponding to Figure 13 of Embodiment 1.

[0130] The difference from Embodiment 1 ( Figure 13 ) is that the thickness of the base plate 130 outside the region of the pin fins 131 is thicker than that of the base plate 130 in the region of the pin fins 131. Here, the base plate 130 in the region where the flat fins 132 exist also becomes thicker. In addition, there are two flat fins 132 extending in the long side direction of the base plate 130 and the thick portions of the base plate 130 near the sealing portion. Other structures are the same as those in Embodiment 1 ( Figure 13 ).

[0131] The effects of the structure of this embodiment will be described.

[0132] Since the long side of the base plate 130 is strengthened by the flat fins 132 extending in the long side direction of the base plate 130, the water pressure resistance is improved. However, according to this embodiment, since the base plate 130 is further thickened outside the region of the pin fins 131, the water pressure resistance at the center in the long side direction and the center in the short side direction of the base plate 130 is further improved.

[0133] The water pressure resistance on both the long side and the short side of the base plate 130 is further improved compared with that in Embodiment 1. The base plate 130 can be made thinner, the channel for heat dissipation of the power semiconductor element can be shortened, and the thermal resistance can be reduced.

[0134] Embodiment 8

[0135] Refer to Figure 19 , and the power semiconductor module according to Embodiment 8 of the present invention will be described.Figure 19 is a cross-sectional view of the power unit of this embodiment, corresponding to that of Embodiment 1 Figure 13 .

[0136] The differences from Embodiment 7 are as follows. There are both two flat fins 132 extending in the long side direction of the base plate 130 and two flat fins 132 extending in the short side direction of the base plate 130. In addition, in both the long side direction and the short side direction of the base plate 130, the thickness of the base plate 130 outside the area of the pin fins 131 is thicker than that of the base plate 130 in the area of the pin fins 131. Other structures are the same as those in Embodiment 7.

[0137] The effects of the structure of this embodiment will be described.

[0138] Since the long side and the short side of the base plate 130 are strengthened by the flat fins 132 extending in the long side direction of the base plate 130 and the flat fins 132 extending in the short side direction, the water pressure resistance is improved. However, according to this embodiment, since the base plate 130 becomes thicker outside the area of the pin fins 131, the water pressure resistance at the center in the long side direction and the center in the short side direction of the base plate 130 is further improved.

[0139] Since the water pressure resistance of the long side and the short side of the base plate 130 is higher than that in Embodiment 1 and Embodiment 7, the base plate 130 can be made thinner, the channel for heat dissipation of the power semiconductor element can be shortened, and the thermal resistance can be reduced.

[0140] Embodiment 9

[0141] Refer to Figure 20 , and the power semiconductor module of Embodiment 9 of the present invention will be described. Figure 20 is a top view of the base plate 130 of the power semiconductor module 100 as viewed from the side of the water channel forming body 70, that is, a top view of the heat dissipation fin forming surface of the base plate 130.

[0142] The differences from Embodiment 1( Figure 10 ) are that there is also a flat fin 132 extending in the long side direction at the center of the base plate 130, and the total number of flat fins 132 is three. Other structures are the same as those in Embodiment 1( Figure 10 ).

[0143] The effects of the structure of this embodiment will be described.

[0144] In Embodiment 1( Figure 10)In [description], two flat fins 132 extending in the longitudinal direction of the base plate 130 are arranged in a manner sandwiching the region of the needle-like fin 131. However, in this embodiment, a flat fin 132 is also added at the center of the base plate 130. By adding the flat fin 132 at the central portion of the base plate 130, the flexure of the central portion of the base plate 130 caused by the water pressure due to the pressure loss is reduced, the flexure of the sealing portion is also reduced, and the water pressure resistance at the center of the long side is improved compared to Embodiment 1.

[0145] Since the water pressure resistance on the long side of the base plate 130 is improved, the base plate 130 can be made thinner, the channel for heat dissipation of the power semiconductor element becomes shorter, and thus the thermal resistance can be reduced.

[0146] In addition, compared with Embodiment 1 ( Figure 10 ), there is a concern about the increase in pressure loss caused by the addition of the flat fin 132 at the central portion of the base plate 130. However, since the cooling water 60 passes under the flat fin 132 which is lower than the needle-like fin 131, it does not become a flow path resistance larger than necessary, and the increase in pressure loss can be suppressed to the minimum.

[0147] Embodiment 10

[0148] Refer to Figure 21 to describe the power semiconductor module of Embodiment 10 of the present invention. Figure 21 is a top view of the base plate 130 of the power semiconductor module 100 as viewed from the side of the water channel forming body 70, that is, a top view of the heat dissipation fin forming surface of the base plate 130.

[0149] The difference from Embodiment 1 ( Figure 10 ) lies in the following aspects. The plate-like fin 132 is arranged near the center of the base plate 130 and is a bent component. Other structures are the same as those in Embodiment 1 ( Figure 10 ).

[0150] Explain the effects of the structure of this embodiment.

[0151] In Embodiment 1 ( Figure 10 ), two flat fins 132 extending in the longitudinal direction of the base plate 130 are arranged in a manner sandwiching the region of the needle-like fin 131. However, in this embodiment, one plate-like fin 132 is arranged at the center of the base plate 130. Since the plate-like fin 132 is not straight but bent, it is equivalent to effectively arranging a plate-like fin with a wider width in the short side direction. Thereby, the flexure of the central portion of the base plate 130 caused by the water pressure due to the pressure loss is reduced, the flexure of the sealing portion 135 is also reduced, and thus the water pressure resistance at the center of the long side is improved.

[0152] Since the water pressure resistance on the long side of the base plate 130 is improved, the base plate 130 can be made thinner, the heat dissipation path of the power semiconductor element can be shortened, and the thermal resistance can be reduced.

[0153] In addition, there is a concern about an increase in pressure loss caused by arranging the plate-shaped fin 132 at the center of the base plate 130. However, since the cooling water 60 passes under the plate-shaped fin 132 which is lower than the needle-shaped fin 131, it will not cause a flow path resistance larger than necessary, and the increase in pressure loss can be suppressed to the minimum.

[0154] The above-described embodiments are shown by taking the main power conversion device for railway vehicles as an example, but can also be applied to power conversion devices for automobiles or trucks, power conversion devices for ships or aircraft, industrial power conversion devices used as control devices for motors driving factory equipment, and household power conversion devices used as control devices for motors driving a household solar power generation system or household electrical appliances.

[0155] In addition, the present invention is not limited to the above-described embodiments and includes various modification examples. For example, the above-described embodiments are embodiments described in detail for easy understanding of the present invention and are not limited to having all the structures described. Also, a part of the structure of one embodiment can be replaced with the structure of another embodiment, and also, the structure of another embodiment can be added to the structure of one embodiment. In addition, addition, deletion, or replacement of other structures can be made to a part of the structure of each embodiment.

[0156] Description of reference numerals

[0157] 1— trolley wire, 2— transformer, 3— smoothing capacitor, 4— converter, 5— inverter, 6— AC motor, 10— main power conversion device, 20— cooling device, 31— upper branch switching element, 32— lower branch switching element, 33— upper branch rectifying element, 34— lower branch rectifying element, 35— branch, 40p, 40n— DC wiring, 40r, 40s, 40u, 40v, 40w— AC wiring, 50— pump, 51— low-temperature cooling water (liquid refrigerant), 52— low-temperature side distribution pipe, 53— power unit, 54— high-temperature cooling water, 55— high-temperature side distribution pipe, 56— radiator, 57— fan, 58— cooling air, 59— expansion tank, 60— cooling water (liquid refrigerant) in waterway forming body, 70— waterway forming body, 71— low-temperature side cooling water joint, 72— high-temperature side cooling water joint, 73— O-ring, 74— O-ring groove, 75— opening, 76— bolt hole for fixing power semiconductor module, 77— flow path between adjacent modules, 100— power semiconductor module, 101— power semiconductor element, 102— insulating substrate, 110p— positive DC terminal, 110n— negative DC terminal, 110ac— AC terminal, 110g— gate terminal, 111— weak electric system electrode, 112— threaded hole for fixing gate drive substrate, 113— box body, 114— through hole for fixing power semiconductor module, 130— base plate (substrate plate), 131— pin fin (heat dissipation fin), 132— flat fin (plate-like fin), 135— sealing part, 200— converter control circuit, 201— inverter control circuit, 210— drive signal, 211— drive signal.

Claims

1. A semiconductor device is a direct water-cooling type semiconductor device that cools the surface of a substrate opposite to the surface on which semiconductor elements are mounted using a refrigerant, and is characterized in that Comprising: A base plate; A semiconductor module mounted on the first surface of the above-mentioned base plate; and Pin fins and plate fins mounted on the second surface of the above-mentioned base plate opposite to the above-mentioned first surface, The length of the above-mentioned plate fin from the above-mentioned second surface is shorter than the length of the above-mentioned pin fin from the above-mentioned second surface.

2. The semiconductor device according to claim 1, characterized in that In the above-mentioned second surface, the region where the above-mentioned pin fins are arranged is located in a region sandwiched by at least two of the above-mentioned plate fins.

3. The semiconductor device according to claim 2, characterized in that The region where the above-mentioned pin fins are arranged is located in a region sandwiched by the main surfaces of at least two of the above-mentioned plate fins.

4. The semiconductor device according to claim 2, characterized in that The region where the above-mentioned pin fins are arranged is located in a region sandwiched by two of the above-mentioned plate fins extending in the long side direction of the above-mentioned base plate and two of the above-mentioned plate fins extending in the short side direction of the above-mentioned base plate.

5. The semiconductor device according to claim 4, characterized in that Two of the above-mentioned plate fins extending in the long side direction are connected to two of the above-mentioned plate fins extending in the short side direction, The region where the above-mentioned pin fins are arranged is located in a region surrounded by the connected above-mentioned plate fins.

6. The semiconductor device according to claim 1, characterized in that The above-mentioned plate fins are arranged to extend in at least one of the long side direction and the short side direction of the above-mentioned base plate, The length of the center in the extending direction of the above-mentioned plate fin is longer than the length of the end portion.

7. The semiconductor device according to claim 1, characterized in that The thickness of the base plate outside the region where the above-mentioned pin fins are arranged is thicker than the thickness of the base plate in the region where the above-mentioned pin fins are arranged.

8. The semiconductor device according to claim 1, characterized in that The main surface of the above-mentioned plate fin is perpendicular to the water flow direction of the above-mentioned refrigerant.

9. The semiconductor device according to claim 1, characterized in that The above-mentioned plate fin has a buckling portion.

10. The semiconductor device according to claim 1, characterized in that The above-mentioned base plate has a sealing portion connected to a water channel forming body that becomes the flow path of the above-mentioned refrigerant, and the above-mentioned plate fin is arranged near the above-mentioned sealing portion.

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