Power Semiconductor Device

Abstract

The power semiconductor device (100) includes a housing (1) having an air passage (10), a heat sink (2) held in the housing (1) with a plurality of fins (21) arranged in the air passage (10), and a plurality of power modules (3). An uneven surface (20a) is formed on the other surface of the heat sink base (20). The power modules (3) have uneven portions (30a) that fit into the uneven surface (20a) of the heat sink base (20), and the uneven portions (30a) are fitted into the uneven surface (20a) of the heat sink base (20), and are provided at intervals along the traveling direction of the air flow (A). One of the power modules (3) adjacent to each other in the traveling direction of the air flow (A) is offset from the other adjacent power module (3) in a direction perpendicular to the traveling direction of the air flow (A).

Description

[Technical field]

[0001] The present disclosure relates to a power semiconductor device having a heat sink and a power module mounted thereon. [Background technology]

[0002] Conventionally, a power semiconductor device equipped with a heat sink and a power module is known. For example, a power semiconductor device disclosed in Patent Document 1 includes a base, a heat sink having a plurality of fins arranged in parallel at intervals on one surface of the base, and a plurality of power semiconductor modules arranged on the other surface of the base. The power semiconductor device described in Patent Document 1 reduces a temperature rise of the power semiconductor module by blowing cooling air along the row of fins of the heat sink. The plurality of power semiconductor modules are arranged in an oblique line with respect to the flow direction of the cooling air so that the power semiconductor module on the downwind side is not affected by the heat generated by the power semiconductor module on the upwind side. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-66123 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the power semiconductor device disclosed in Patent Document 1, a plurality of power semiconductor modules are aligned diagonally with respect to the flow direction of the cooling air, and therefore, taking into consideration the area of ​​the base on which the power semiconductor modules are mounted, it is difficult to arrange the power semiconductor modules with sufficient spacing between them, and there is a risk that the power semiconductor module on the downwind side will be affected by the heat generated by the power semiconductor module on the upwind side.

[0005] The present disclosure has been made in view of the above, and has an object to obtain a power semiconductor device in which a power semiconductor module on the downwind side is less susceptible to the effects of heat generated by a power semiconductor module on the upwind side. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object, the power semiconductor device according to the present disclosure comprises a housing having an air passage formed with an inlet and an outlet for an air flow facing each other, a flat heat sink base, and a heat sink having a plurality of flat fins arranged in parallel at intervals on one surface of the heat sink base, the heat sink being held in the housing with the plurality of fins arranged in the air passage, and a plurality of power modules provided on the other surface of the heat sink base. An uneven surface is formed on the other surface of the heat sink base. The power modules have uneven portions that fit into the uneven surface of the heat sink base, and the uneven portions are fitted into the uneven surface of the heat sink base and are provided at intervals along the traveling direction of the air flow, and one of the power modules adjacent to each other in the traveling direction of the air flow has a height difference with respect to the other adjacent power module. Within the area where the uneven surface of the heat sink base is formed They are offset in a direction perpendicular to the airflow direction. Effect of the Invention

[0007] The power semiconductor device according to the present disclosure has an advantage that the power semiconductor module on the downwind side is less susceptible to the influence of heat generated by the power semiconductor module on the upwind side. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view showing a power semiconductor device according to a first embodiment; [Diagram 2] Cross-sectional view taken along the line II-II in FIG. [Diagram 3] Cross-sectional view taken along the line III-III in FIG. [Figure 4] FIG. 1 is a plan view showing a power semiconductor device according to a first comparative example; [Diagram 5] Cross-sectional view taken along the arrows VV in Figure 4 [Figure 6] FIG. 1 is a contour diagram showing the temperature distribution of air flowing from the inlet to the outlet in the power semiconductor device of Comparative Example 1. [Figure 7] FIG. 1 is a contour diagram showing a temperature distribution of air flowing from an inlet to an outlet in a power semiconductor device according to a first embodiment; [Figure 8] FIG. 11 is a plan view showing a power semiconductor device according to a second comparative example. [Figure 9] IX-IX cross-sectional view shown in FIG. [Figure 10] Cross-sectional view taken along the arrow XX in FIG. [Figure 11] FIG. 1 is a plan view showing a first modification of the uneven surface of the power semiconductor device according to the first embodiment; [Figure 12] FIG. 1 is a plan view showing a second modified example of the concave-convex surface of the power semiconductor device according to the first embodiment; [Figure 13] FIG. 1 is a plan view showing a third modified example of the uneven surface of the power semiconductor device according to the first embodiment; [Figure 14] FIG. 11 is a plan view showing a power semiconductor device according to a second embodiment; [Figure 15] Cross-sectional view taken along the line XV-XV in FIG. [Figure 16] XVI-XVI cross-sectional view shown in FIG. 14 [Figure 17] FIG. 11 is a plan view showing a mounting plate of a power semiconductor device according to a second embodiment; [Figure 18] FIG. 11 is a plan view showing a power semiconductor device according to a third embodiment. [Figure 19] 19 is a cross-sectional view taken along the line XIX-XIX in FIG. [Figure 20] FIG. 11 is a plan view showing a mounting plate of a power semiconductor device according to a third embodiment; [Figure 21] FIG. 13 is a plan view showing a modification of the power semiconductor device according to the third embodiment; [Figure 22] FIG. 13 is a plan view showing a mounting plate of a modified example of the power semiconductor device according to the third embodiment; [Diagram 23] FIG. 13 is a vertical cross-sectional view showing a schematic diagram of a power semiconductor device according to a fourth embodiment. [Figure 24]FIG. 13 is a vertical cross-sectional view showing a first modified example of the power semiconductor device according to the fourth embodiment; [Diagram 25] FIG. 13 is a vertical cross-sectional view showing a schematic diagram of a second modified example of the power semiconductor device according to the fourth embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, power semiconductor devices according to embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] Embodiment 1 Fig. 1 is a plan view of a power semiconductor device according to a first embodiment. The white arrows in Fig. 1 indicate the direction of travel of air flow A. Fig. 2 is a cross-sectional view taken along the line II-II in Fig. 1. Fig. 3 is a cross-sectional view taken along the line III-III in Fig. 1. Note that some hatching has been omitted from the cross-sectional views in order to make it easier to see the components of the power module 3.

[0011] As shown in FIGS. 1 to 3, a power semiconductor device 100 according to the first embodiment includes a housing 1, a heat sink 2, a plurality of power modules 3, and a cooling fan 4. The housing 1 includes a heat sink 2, a plurality of power modules 3, and a cooling fan 4. The power semiconductor device 100 includes a housing 1, a heat sink 2, a plurality of power modules 3, and a cooling fan 4.

[0012] As shown in FIG. 1 to FIG. 3, the housing 1 forms an air passage 10 in which the inlet 10a and the outlet 10b of the air flow A face each other, and holds a heat sink-integrated power module in which a heat sink 2 and a plurality of power modules 3 are integrated. The housing 1 is formed into a concave shape with a bottom surface portion 11 and a pair of side surfaces 12. The housing 1 has both ends extending along the traveling direction of the air flow A open, with one open end being the inlet 10a of the air flow A and the other open end being the outlet 10b of the air flow A. The air passage 10 is a space surrounded by the bottom surface portion 11 and the pair of side surfaces 12. In the example shown in FIG. 1, the traveling direction of the air flow A is from the inlet 10a to the outlet 10b, but is not limited thereto. The outlet 10b may be the inlet, the inlet 10a in which the cooling fan 4 is arranged is the outlet, and the air flow may be the opposite direction from the outlet 10b to the inlet 10a.

[0013] The housing 1 is made of plated steel sheet. Plated steel sheet is a material that has enough rigidity to hold the heat sink integrated power module and can realize a thinner and lighter body. The housing 1 may be made of a material other than plated steel sheet.

[0014] The heat sink 2 is integrated with a plurality of power modules 3 and dissipates heat generated by the power modules 3. As shown in Fig. 2 and Fig. 3, the heat sink 2 has a flat heat sink base 20 and a plurality of flat fins 21 arranged in parallel at intervals on one surface of the heat sink base 20. As an example, the heat sink 2 is a crimped heat sink in which the heat sink base 20 and the fins 21 are integrated by "crimping". The heat sink 2 is held in the housing 1 with the plurality of fins 21 arranged in the air passage 10.

[0015] The heat sink base 20 has a rectangular shape, for example. The heat sink base 20 is made of a metal material with relatively high thermal conductivity so that heat generated by the power module 3 can be efficiently transferred to the fins 21. The heat sink base 20 is made of a metal material that is resistant to corrosion, such as aluminum or an aluminum alloy, for example. The heat sink base 20 is manufactured by a processing method such as cutting, die casting, forging, or extrusion.

[0016] On the other surface of the heat sink base 20, in one region where the multiple power modules 3 are provided, an uneven surface 20a is formed in which recesses and protrusions extend along the traveling direction of the air flow A. The one region where the multiple power modules 3 are provided is, for example, the entire surface of the other surface of the heat sink base 20.

[0017] With the multiple fins 21 housed inside the concave housing 1, the heat sink base 20 has its outer periphery placed on the upper end surface of the side surface portion 12 and is fixed to the side surface portion 12 with a joining member (not shown) such as a screw. Note that the side surface portion 12 is provided with a screw hole (not shown) for screwing in the screw or the like. Also, the heat sink base 20 is provided with a screw hole or a through hole (not shown) at a position corresponding to the screw hole provided in the side surface portion 12.

[0018] The fins 21 are heat dissipation components made of rectangular thin plates. The fins 21 are made of a metal material with relatively high thermal conductivity so as to dissipate heat generated by the power module 3. As an example, the fins 21 are made of a metal material that is resistant to corrosion, such as aluminum or an aluminum alloy. By using a rolled material of a metal material such as aluminum for the fins 21, it is possible to achieve both workability and heat dissipation properties of the fins 21.

[0019] Each of the multiple fins 21 is inserted into a fin insertion groove (not shown) formed on one surface of the heat sink base 20 and is fixed to the heat sink base 20 by crimping. When the heat sink 2 is a crimped heat sink, there is no processing restriction on the aspect ratio in die casting and extrusion, so the fins 21 can be freely designed and the heat dissipation capacity can be improved. However, the heat sink 2 is not limited to a crimped heat sink and may be one manufactured by other processing methods. For example, the heat sink 2 may be manufactured by integrally manufacturing the fins 21 and the heat sink base 20 by extrusion or die casting. In addition, in a heat sink-integrated power module, a heat sink 2 manufactured by cutting or forging may be used.

[0020] The power module 3 is a power semiconductor module and is a resin mold type. As shown in Fig. 1, a plurality of power modules 3 are provided at intervals along the traveling direction of the air flow A. In the power semiconductor device 100 shown in Fig. 1, six power modules 3 arranged in two columns and three rows are mounted as an example. Note that the number of power modules 3 is not limited to six as shown in the figure, and it is sufficient that there are two or more power modules arranged at intervals along the traveling direction of the air flow A.

[0021] 1, in the power semiconductor device 100 according to the first embodiment, one of the power modules 3 adjacent to each other in the traveling direction of the air flow A is offset from the other adjacent power module 3 in the direction X perpendicular to the traveling direction of the air flow A. Specifically, of the three power modules 3 provided along the traveling direction of the air flow A, the middle power module 3 is offset from the windwardest power module 3 and the leewardest power module 3 in the direction X perpendicular to the traveling direction of the air flow A.

[0022] As shown in Figures 1 to 3, the power module 3 includes a fin base 30, an insulating material 31, a metal conductor 32, a semiconductor element 33, a bonding material 34, a wiring wire 35, a control terminal 36, a main terminal 37, and a sealing material 38.

[0023] The fin base 30 is a rectangular flat plate smaller than the heat sink base 20, and is a connection part for connecting the power module 3 to the heat sink 2. The fin base 30 is made of a metal material with relatively high thermal conductivity so that heat generated by the power module 3 can be efficiently transferred to the heat sink 2. As an example, the fin base 30 is made of a metal material that is resistant to corrosion, such as aluminum or an aluminum alloy. The fin base 30 is produced by a processing method such as cutting, die casting, forging, or extrusion.

[0024] The fin base 30 has an uneven portion 30a formed on one surface facing the heat sink base 20, which fits into the uneven surface 20a of the heat sink base 20. The power module 3 is integrated with the heat sink 2 by fitting the uneven portion 30a of the fin base 30 and the uneven surface 20a of the heat sink base 20 by press processing. The power module 3 is installed by freely changing the arrangement within the range of the area where the uneven surface 20a is formed. In addition, the power module 3 is a greaseless power module in which no thermally conductive grease is used between the power module 3 and the heat sink 2. The greaseless power module can improve the heat dissipation performance of the heat generated in the power module 3 compared to a power module using thermally conductive grease, so it is suitable for use in a power semiconductor device with a large power capacity. In addition, in the power semiconductor device 100, when replacing the power module 3, since no thermally conductive grease is used, there is no need to remove and relocate the thermally conductive grease, and productivity and maintainability are good.

[0025] The materials of the heat sink base 20, the fins 21, and the fin base 30 are not limited to the aluminum-based materials described above, and may be other materials. That is, the combination of materials of the heat sink base 20, the fins 21, and the fin base 30 may be a combination of materials different from the above. For example, by making the fins 21 out of a copper-based plate component having a higher thermal conductivity than an aluminum-based material, the heat dissipation capability of the fins 21 is further improved compared to when the fins 21 are plate components made of an aluminum-based material.

[0026] The insulating material 31 is an insulating sheet having heat dissipation properties. The insulating material 31 is fixed to the other surface of the fin base 30. The insulating material 31 insulates the components of the power module 3 sealed by the sealing material 38 from the heat sink base 20, and dissipates heat generated by the semiconductor element 33 to the heat sink base 20. The insulating material 31 has heat dissipation properties equal to or greater than those of the sealing material 38.

[0027] The metal conductor 32 is a substrate on which a semiconductor element 33 is mounted, and dissipates heat generated by the semiconductor element 33 to the insulating material 31 .

[0028] The semiconductor element 33 is a semiconductor element for power control. Examples of the semiconductor element 33 are a rectifier diode, a power transistor, a thyristor, and an IGBT (Insulated Gate Bipolar Transistor). The semiconductor element 33 is exemplified by an element formed of silicon (Si) or an element formed of a wide band gap semiconductor having a larger band gap than silicon. Examples of wide band gap semiconductors are silicon carbide (SiC), gallium nitride-based materials, and diamond. The semiconductor element 33 using a wide band gap semiconductor has a high allowable current density and a low power loss, so that the power module 3 can be made smaller, and thus the heat sink 2 and the power semiconductor device 100 can be made smaller.

[0029] The bonding material 34 is, for example, solder, and bonds the metal conductor 32 and the semiconductor element 33. The semiconductor element 33 is die-bonded to the metal conductor 32 by using the bonding material 34. Note that the bonding material 34 is not limited to solder, and may have another configuration.

[0030] The wiring wires 35 electrically connect the semiconductor elements 33 to each other. The wiring wires 35 also electrically connect the semiconductor elements 33 to the main terminals 37.

[0031] The control terminal 36 and the main terminal 37 are connected to the semiconductor element 33 to supply power to the semiconductor element 33 or to transmit signals between the semiconductor element 33 and an external device.

[0032] The sealing material 38 is formed of a thermosetting resin such as epoxy, and ensures insulation between components of the power module 3. The sealing material 38 is a transfer mold formed by transfer molding, for example. However, the sealing material 38 is not limited to a thermosetting resin. Furthermore, the molding method of the sealing material 38 is not limited to transfer molding.

[0033] The cooling fan 4 generates an air flow A that flows from the inlet 10a to the outlet 10b of the housing 1. The cooling fan 4 is provided at the inlet 10a of the housing 1. The means for attaching the cooling fan 4 to the housing 1 may be a fan attachment structure provided at a part of the housing 1 to attach the cooling fan 4, or an attachment member separate from the housing 1 may be provided at the inlet 10a to attach the cooling fan 4.

[0034] Fig. 4 is a plan view showing the power semiconductor device of Comparative Example 1. Fig. 5 is a cross-sectional view taken along the line VV shown in Fig. 4. Fig. 6 is a contour diagram showing the temperature distribution of air flowing from the inlet to the outlet in the power semiconductor device of Comparative Example 1.

[0035] 4 and 5, a plurality of power modules 3 are provided at intervals along the direction of travel of the air flow A. As an example, the power modules 3 are arranged in 2 columns and 3 rows, and are aligned along the direction of travel of the air flow A. In this case, as shown in FIG. 6, the temperature of the air flowing between the fins 21 of the heat sink 2 from the upwind side to the downwind side increases continuously. That is, the semiconductor element 33 of the downwind side power module 3 is affected by the heat generated by the semiconductor element 33 of the upwind side power module 3, and the temperature of the downwind side power module 3 increases due to thermal interference.

[0036] 1, in the power semiconductor device 100 according to the first embodiment, one of the power modules 3 adjacent to each other in the traveling direction of the air flow A is offset from the other adjacent power module 3 in the direction X perpendicular to the traveling direction of the air flow A. Specifically, of the three power modules 3 provided along the traveling direction of the air flow A, the middle power module 3 is offset from the windwardest power module 3 and the leewardest power module 3 in the direction X perpendicular to the traveling direction of the air flow A.

[0037] 7 is a contour diagram showing the temperature distribution of air flowing from the inlet to the outlet in the power semiconductor device according to the first embodiment. As shown in FIG. 7, the power semiconductor device 100 according to the first embodiment can reduce cumulative thermal interference, so that the semiconductor element 33 of the power module 3 on the downwind side is less affected by heat generated from the semiconductor element 33 of the power module 3 on the upwind side, and low-temperature air can be sent to the downwind side. Therefore, the power semiconductor device 100 according to the first embodiment can effectively suppress the temperature rise of the power module 3.

[0038] Fig. 8 is a plan view showing a power semiconductor device of Comparative Example 2. Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8. Fig. 10 is a cross-sectional view taken along line XX in Fig. 8.

[0039] In the power semiconductor device 100B of Comparative Example 2 shown in Figs. 8 to 10, a plurality of uneven surfaces 20a, in which recesses and protrusions extend along the traveling direction of the air flow A, are formed for each power module 3 on the other surface of the heat sink base 20. The power module 3 has a fin base 30 on which uneven portions 30a that fit into the uneven surface 20a of the heat sink base 20 are formed. In the power semiconductor device 100B, the position of the power module 3 to be installed on the heat sink base 20 is determined at the design stage of the uneven surface 20a, so if it becomes necessary to change the arrangement of the power module 3 after the design, it is necessary to fabricate a new heat sink base 20.

[0040] 1, in the power semiconductor device 100 according to the first embodiment, an uneven surface 20a is formed on the other surface of the heat sink base 20. The power module 3 has a fin base 30 on which an uneven portion 30a that fits into the uneven surface 20a of the heat sink base 20 is formed. That is, in the power semiconductor device 100 according to the first embodiment, the power module 3 can be freely arranged within the region in which the uneven surface 20a of the heat sink base 20 is formed, so that the degree of freedom in design is high and the productivity of the heat sink integrated power module can be increased.

[0041] FIG. 11 is a plan view showing a first modified example of the uneven surface of the power semiconductor device according to the first embodiment. FIG. 12 is a plan view showing a second modified example of the uneven surface of the power semiconductor device according to the first embodiment. FIG. 13 is a plan view showing a third modified example of the uneven surface of the power semiconductor device according to the first embodiment. The uneven surface 20a of the heat sink base 20 is not limited to a configuration in which the recesses and protrusions extend along the direction of travel of the air flow A as shown in FIG. 1. As shown in FIG. 11, the uneven surface 20a may be configured so that the recesses and protrusions extend along a direction intersecting the direction of travel of the air flow A, such as a direction perpendicular to the direction of travel of the air flow A. In addition, the recesses and protrusions are not limited to the configuration in which they are continuously formed as shown in FIG. 1, and may be configured to be intermittently formed along the extending direction as shown in FIG. 12. In addition, as shown in FIG. 13, the uneven surface 20a may be configured so that dot-shaped protrusions are aligned, or may have other configurations. In short, the uneven surface 20a may have a configuration in which the uneven portion 30a of the power module 3 fits, and the shapes of the recesses and protrusions, the orientations of the recesses and protrusions, and the ranges in which the recesses and protrusions are formed are appropriately changed according to the configuration of the power semiconductor device 100. In this case, the uneven portion 30a of the power module 3 is formed in accordance with the configuration of the uneven surface 20a.

[0042] Embodiment 2 Next, a power semiconductor device 101 according to a second embodiment will be described. Fig. 14 is a plan view showing the power semiconductor device according to the second embodiment. Fig. 15 is a cross-sectional view taken along line XV-XV in Fig. 14. Fig. 16 is a cross-sectional view taken along line XVI-XVI in Fig. 14. Fig. 17 is a plan view showing a mounting plate of the power semiconductor device according to the second embodiment. Note that some hatching has been omitted from the cross-sectional view in order to make it easier to see the components of the power module 3.

[0043] As shown in FIGS. 14 to 16, the housing 1 of the power semiconductor device 101 according to the second embodiment has a structure in which a plurality of openings 14a are formed at intervals along the traveling direction of the air flow A on one side forming the air passage 10. Specifically, the housing 1 has a concave-shaped housing 13 formed by a bottom surface portion 11 and a pair of side surfaces 12, and a mounting plate 14 disposed opposite the bottom surface portion 11 and covering the opening surface of the housing 13. The housing 1 is formed into a rectangular tube by the housing 13 and the mounting plate 14. The housing 1 has both ends extending along the traveling direction of the air flow A open, with one open end serving as an inlet 10a for the air flow A blown from the cooling fan 4 and the other open end serving as an outlet 10b for the air flow A. The air passage 10 is a space surrounded by the housing 13 and the mounting plate 14. In the example shown in FIG. 14, the direction of travel of the air flow A is from the inlet 10a to the outlet 10b, but this is not limited to this. The air flow A may travel in the opposite direction from the outlet 10b to the inlet 10a, with the outlet 10b serving as the inlet and the inlet 10a where the cooling fan 4 is located serving as the outlet.

[0044] The housing 13 and the mounting plate 14 are made of plated steel plate. Plated steel plate is a material that has the rigidity to hold the heat sink-integrated power module and can be made thin and lightweight. The housing 13 and the mounting plate 14 may be made of a material other than plated steel plate.

[0045] The mounting plate 14 has its outer periphery placed on the upper end surface of the side surface portion 12, and is fixed to the side surface portion 12 with a connecting member (not shown) such as a screw. The side surface portion 12 is provided with a screw hole (not shown) for screwing in a connecting member such as a screw. The mounting plate 14 is also provided with a screw hole or a through hole (not shown) at a position corresponding to the screw hole provided in the side surface portion 12.

[0046] 17, the mounting plate 14 has three openings 14a of the same shape and size aligned at intervals along the direction of movement of the air flow A. As an example, the openings 14a have a rectangular shape that is long in a direction X perpendicular to the direction of movement of the air flow A when the power semiconductor device 101 is viewed in a plan view.

[0047] As shown in FIG. 14, the heat sink 2 is provided as an individual piece for each opening 14a, and as shown in FIG. 15 and FIG. 16, the fins 21 are fitted through the openings 14a and are supported by the housing 1 in a state in which they are arranged in the air passage 10. The heat sink 2 is formed to match the size and shape of the openings 14a. With the fins 21 fitted through the openings 14a and arranged in the air passage 10, the outer peripheral edge of the heat sink base 20 is placed on the upper surface of the mounting plate 14 and fixed to the mounting plate 14 with a joining member (not shown) such as a screw. The mounting plate 14 is provided with a screw hole (not shown) for screwing in a joining member such as a screw. The heat sink base 20 is also provided with a screw hole or a through hole (not shown) at a position corresponding to the screw hole provided in the mounting plate 14.

[0048] Two power modules 3 arranged side by side are integrated into the individualized heat sink 2. That is, the power semiconductor device 101 according to the second embodiment has a configuration in which the heat sink 2 is partially omitted compared to the configuration of the first embodiment, and therefore the weight of the device can be reduced. Furthermore, in the power semiconductor device 101 according to the second embodiment, when a power module 3 fails, it is only necessary to replace the heat sink 2 on which the failed power module 3 is mounted, and therefore maintainability is improved.

[0049] Also in the power semiconductor device 101 according to the second embodiment, one of the power modules 3 adjacent to each other in the traveling direction of the air flow A is offset from the other adjacent power module 3 in the direction X perpendicular to the traveling direction of the air flow A. Specifically, of the three power modules 3 provided along the traveling direction of the air flow A, the middle power module 3 is offset from the windwardest power module 3 and the leewardest power module 3 in the direction X perpendicular to the traveling direction of the air flow A.

[0050] As a result, the power semiconductor device 101 according to the second embodiment can reduce cumulative thermal interference, so that the semiconductor elements 33 of the power module 3 on the downwind side are less susceptible to the heat generated by the semiconductor elements 33 of the power module 3 on the upwind side, and low-temperature air can be sent to the downwind side. Therefore, the power semiconductor device 101 according to the second embodiment can effectively suppress the temperature rise of the power module 3.

[0051] Furthermore, in the power semiconductor device 101 according to the second embodiment, the power module 3 can be freely positioned within the area in which the uneven surface 20a of the heatsink base 20 is formed, thereby providing a high degree of design freedom and enabling the productivity of the heatsink-integrated power module to be increased.

[0052] Incidentally, the housing 13 and the mounting plate 14 are configured to be joined after being formed as separate members, but may be configured to be integrally formed as one member. The number of openings 14a is not limited to three as shown in the figure, and may be two, or four or more. The shape of the openings 14a is not limited to a rectangular shape elongated in the direction X perpendicular to the traveling direction of the air flow A, and may be another shape such as a square, or may be a rectangular shape elongated along the traveling direction of the air flow A. The number of power modules 3 provided in one individualized heat sink 2 is not limited to two as shown in the figure, and may be one, or three or more.

[0053] Embodiment 3 Next, the power semiconductor devices 102 and 102A according to the third embodiment will be described. Fig. 18 is a plan view showing the power semiconductor device according to the third embodiment. Fig. 19 is a cross-sectional view taken along line XIX-XIX shown in Fig. 18. Fig. 20 is a plan view showing a mounting plate of the power semiconductor device according to the third embodiment.

[0054] As shown in Figs. 18 to 20, the housing 1 of the power semiconductor device 102 according to the third embodiment has a structure in which a plurality of openings 14a are formed at intervals along the traveling direction of the air flow A on one side forming the air passage 10. Specifically, the housing 1 has a concave-shaped housing 13 formed by a bottom surface portion 11 and a pair of side surfaces 12, and a mounting plate 14 disposed opposite the bottom surface portion 11 and covering the opening surface of the housing 13. The housing 1 is formed into a rectangular tube by the housing 13 and the mounting plate 14. The housing 1 has both ends extending along the traveling direction of the air flow A open, with the open end serving as an inlet 10a for the air flow A blown from the cooling fan 4 and the other open end serving as an outlet 10b for the air flow A. The air passage 10 is a space surrounded by the housing 13 and the mounting plate 14. In the example shown in FIG. 18, the direction of travel of the air flow A is from the inlet 10a to the outlet 10b, but this is not limited to this. The air flow A may travel in the opposite direction from the outlet 10b to the inlet 10a, with the outlet 10b serving as the inlet and the inlet 10a where the cooling fan 4 is located serving as the outlet.

[0055] The housing 13 and the mounting plate 14 are made of plated steel plate. Plated steel plate is a material that has the rigidity to hold the heat sink 2 integrated with the multiple power modules 3, and can be made thin and lightweight. The housing 13 and the mounting plate 14 may be made of a material other than plated steel plate.

[0056] The mounting plate 14 has its outer periphery placed on the upper end surface of the side surface portion 12, and is fixed to the side surface portion 12 with a connecting member (not shown) such as a screw. The side surface portion 12 is provided with a screw hole (not shown) for screwing in a connecting member such as a screw. The mounting plate 14 is also provided with a screw hole or a through hole (not shown) at a position corresponding to the screw hole provided in the side surface portion 12.

[0057] Further, the mounting plate 14 has a plurality of openings 14a formed at intervals along the traveling direction of the air flow A. The plurality of openings 14a are arranged in a plurality of rows. In the third embodiment, the openings 14a are, for example, arranged in two columns and three rows, and are aligned along the traveling direction of the air flow A. As shown in FIG. 20, the openings 14a are, for example, rectangular in shape that is long in a direction X perpendicular to the traveling direction of the air flow A.

[0058] As shown in FIG. 18, the heat sink 2 is provided as an individual piece for each opening 14a, and as shown in FIG. 19, the fins 21 are fitted through the openings 14a and are supported by the housing 1 in a state in which they are arranged in the air passage 10. The heat sink 2 is formed to match the size and shape of the openings 14a. With the fins 21 fitted through the openings 14a and arranged in the air passage 10, the outer peripheral edge of the heat sink base 20 is placed on the upper surface of the mounting plate 14 and fixed to the mounting plate 14 with a joining member (not shown) such as a screw. The mounting plate 14 is provided with a screw hole (not shown) for screwing in a joining member such as a screw. The heat sink base 20 is also provided with a screw hole or a through hole (not shown) at a position corresponding to the screw hole provided in the mounting plate 14.

[0059] Each of the individual heat sinks 2 is provided integrally with one power module 3. That is, the power semiconductor device 102 according to the third embodiment has a configuration in which the heat sink 2 is partially omitted compared to the configuration of the first embodiment, and therefore the weight of the device can be reduced. Furthermore, in the power semiconductor device 102 according to the third embodiment, when a power module 3 fails, it is only necessary to replace the heat sink 2 on which the failed power module 3 is mounted, and therefore maintainability is improved.

[0060] Also in the power semiconductor device 102 according to the third embodiment, one of the power modules 3 adjacent to each other in the traveling direction of the air flow A is offset from the other adjacent power module 3 in the direction X perpendicular to the traveling direction of the air flow A. Specifically, of the three power modules 3 provided along the traveling direction of the air flow A, the middle power module 3 is offset from the windwardest power module 3 and the leewardest power module 3 in the direction X perpendicular to the traveling direction of the air flow A.

[0061] As a result, the power semiconductor device 102 according to the third embodiment can reduce cumulative thermal interference, so that the semiconductor elements 33 of the power module 3 on the downwind side are less susceptible to the heat generated by the semiconductor elements 33 of the power module 3 on the upwind side, and low-temperature air can be sent to the downwind side. Therefore, the power semiconductor device 102 according to the third embodiment can effectively suppress the temperature rise of the power module 3.

[0062] Furthermore, in the power semiconductor device 102 according to the third embodiment, the power module 3 can be freely arranged within the area in which the uneven surface 20a of the heatsink base 20 is formed, so that the design freedom is high and the productivity of the heatsink-integrated power module can be improved.

[0063] Although the housing 13 and the mounting plate 14 are formed as separate members and then joined together, they may be integrally molded as one member. The number of openings 14a is not limited to six as shown in the figure, and each row may have two or more openings. The shape of the openings 14a is not limited to a rectangular shape that is long in the direction X perpendicular to the traveling direction of the air flow A, and may be another shape such as a square, or may be a rectangular shape that is long along the traveling direction of the air flow A.

[0064] Fig. 21 is a plan view showing a modification of the power semiconductor device according to the third embodiment. Fig. 22 is a plan view showing a mounting plate of the modification of the power semiconductor device according to the third embodiment. The power semiconductor device 102A shown in Figs. 21 and 22 has a configuration in which one of the openings 14a adjacent to each other in the traveling direction of the air flow A is offset in a direction X perpendicular to the traveling direction of the air flow A with respect to the other adjacent opening 14a. Specifically, among the three openings 14a formed along the inlet 10a and the outlet 10b, the opening 14a located in the middle is offset in a direction X perpendicular to the traveling direction of the air flow A with respect to the opening 14a on the windward side and the opening 14a on the leeward side.

[0065] With this configuration, simply by fitting and installing heat sink-integrated power modules of the same structure into the opening 14a of the mounting plate 14, one power module 3 adjacent to the air flow A in the traveling direction can be offset in the direction X perpendicular to the traveling direction of the air flow A relative to the other adjacent power module 3.

[0066] Embodiment 4 Next, the power semiconductor devices 103, 103A, and 103B according to the fourth embodiment will be described. FIG. 23 is a vertical cross-sectional view that shows a schematic diagram of the power semiconductor device according to the fourth embodiment. As shown in FIG. 23, the power semiconductor device 103 according to the fourth embodiment differs from the configuration of the bottom surface part 11 of the housing 1 in the configuration described in the second and third embodiments. The other configurations are the same as those described in the second or third embodiment. The housing 1 in the fourth embodiment has a plurality of openings 14a formed on one surface that forms the air passage 10 at intervals along the traveling direction of the air flow A. The heat sink 2 is provided in individual pieces for each opening 14a, and is supported by the housing 1 in a state in which the fins 21 are fitted from the openings 14a and arranged in the air passage 10.

[0067] As shown in FIG. 23, the housing 1 has an inclined surface 11a formed on the bottom surface 11 facing the fins 21 of the heat sink 2, which approaches the fins 21 from the inlet 10a forming one end side in the traveling direction of the air flow A toward the outlet 10b forming the other end side. The inclined surface 11a is formed from the inlet 10a to just before the heat sink integrated power module on the most downwind side, and is made into a horizontal surface 11b extending parallel to the fins 21 from the inlet 10a to the outlet 10b. That is, the air passage 10 is configured in a shape in which the cross-sectional area becomes smaller from the upwind side to the downwind side, the cross-sectional area becomes a minimum just before the heat sink integrated power module on the most downwind side, and the same cross-sectional area is maintained from the outlet 10b to the outlet 10b. The horizontal surface 11b does not need to be strictly horizontal, and may be slightly inclined as long as it is approximately horizontal.

[0068] With this configuration, the airflow B, which flows between the bottom surface portion 11 and the fins 21 and has almost no temperature rise, can be made to flow in large amounts between the fins 21 of the heat sink 2 located on the leeward side, and the temperature rise of the power module 3 located on the leeward side can be effectively reduced. The inclined surface 11a is not limited to a configuration formed from the inlet 10a to just before the heat sink-integrated power module located on the most leeward side, but may be formed up to just before the heat sink-integrated power module located in the middle. The inclined surface 11a may be formed continuously from the inlet 10a to the outlet 10b, for example, or may be formed in a stepped manner in combination with the horizontal surface 11b.

[0069] Fig. 24 is a vertical cross-sectional view showing a first modified example of the power semiconductor device according to the fourth embodiment. In the power semiconductor device 103A shown in Fig. 24, a slope 11a is formed on the bottom surface 11 facing the fins 21 of the heat sink 2, approaching the fins 21 from the outlet 10b forming one end side in the traveling direction of the air flow A toward the inlet 10a forming the other end side. That is, the direction of the air flow A in the power semiconductor device 103A shown in Fig. 24 is opposite to that in the power semiconductor device 103 shown in Fig. 23.

[0070] In this way, even in the power semiconductor device 103A shown in FIG. 24, the air flowing between the bottom surface 11 and the fins 21 with almost no increase in temperature can be made to flow in large amounts between the fins 21 of the heat sink 2 located on the downwind side, thereby effectively reducing the heat generation of the power module 3 located on the downwind side.

[0071] Fig. 25 is a vertical cross-sectional view showing a schematic diagram of a second modified example of the power semiconductor device according to the fourth embodiment. The power semiconductor device 103B shown in Fig. 25 is obtained by applying the features of the fourth embodiment described with reference to Fig. 23 to the configuration of the first embodiment. That is, the power semiconductor device 103B has a configuration in which a plurality of power modules 3 are provided on one heat sink 2, and an inclined surface 11a is formed on the bottom surface portion 11 of the housing 1. Although not shown in the figure, the inclined surface 11a of the power semiconductor device 103A shown in Fig. 24 may be applied to the configuration of the first embodiment.

[0072] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0073] 1 housing, 2 heat sink, 3 power module, 4 cooling fan, 10 air passage, 10a inlet, 10b outlet, 11 bottom surface, 11a inclined surface, 11b horizontal surface, 12 side surface, 13 housing, 14 mounting plate, 14a opening, 20 heat sink base, 20a uneven surface, 21 fin, 30 fin base, 30a uneven portion, 31 insulating material, 32 metal conductor, 33 semiconductor element, 34 bonding material, 35 wiring wire, 36 control terminal, 37 main terminal, 38 sealing material, 100, 100A, 100B, 101, 102, 102A, 103, 103A, 103B power semiconductor device, A, B air flow.

Claims

1. A housing having an air passage formed by opposing an air inlet and an air outlet; A flat heat sink base, and a plurality of flat fins provided in parallel with a space on one surface of the heat sink base, and a heat sink held by the housing in a state where the plurality of fins are arranged in the air passage; A plurality of power modules provided on the other surface of the heat sink base; An uneven surface is formed on the other surface of the heat sink base; The power module has an uneven portion that fits into the uneven surface of the heat sink base, the uneven portion is fitted into the uneven surface of the heat sink base, and is provided at intervals along the advancing direction of the air flow; One of the adjacent power modules in the advancing direction of the air flow is offset and arranged in a direction orthogonal to the advancing direction of the air flow within the range of the region where the uneven surface of the heat sink base is formed with respect to the other adjacent power module; A power semiconductor device characterized by the above.

2. The uneven surface is formed such that concave portions and convex portions extend along the advancing direction of the air flow; The power semiconductor device according to claim 1, characterized by the above.

3. The uneven surface is formed such that concave portions and convex portions extend along a direction intersecting the advancing direction of the air flow; The power semiconductor device according to claim 1, characterized by the above.

4. The concave portions and the convex portions are formed continuously or intermittently along the extending direction; The power semiconductor device according to claim 2, characterized by the above.

5. The concave portions and the convex portions are formed continuously or intermittently along the extending direction; The power semiconductor device according to claim 3, characterized by the above.

6. The uneven surface has a configuration in which dot-shaped convex portions are arranged in alignment; The power semiconductor device according to claim 1, characterized by the above.

7. The housing has a plurality of openings formed at intervals along the advancing direction of the air flow on one surface forming the air passage; The heat sink is provided in individual pieces for each opening, and the fins are fitted into the openings and held by the housing in a state of being arranged in the air passage; The power semiconductor device according to any one of claims 1 to 6, characterized by the above.

8. The plurality of openings are formed in alignment along the advancing direction of the air flow; The power semiconductor device according to claim 7, characterized in that...

9. One of the adjacent openings in the traveling direction of the air flow is formed offset in a direction orthogonal to the traveling direction of the air flow with respect to the other adjacent opening. The power semiconductor device according to claim 7, characterized in that...

10. The power module is provided one by one on the individualized heat sinks. The power semiconductor device according to claim 7, characterized in that...

11. The plurality of openings formed at intervals along the traveling direction of the air flow are composed of a plurality of rows. The power semiconductor device according to claim 7, characterized in that...

12. The housing has an inclined surface formed on the bottom surface facing the fins of the heat sink, which approaches the fins from one end side to the other end side in the traveling direction of the air flow. The power semiconductor device according to any one of claims 1 to 6, characterized in that...

Images