Power semiconductor module and power conversion device using the same

Abstract

To provide a power semiconductor module that is unlikely to cause insulation failure.SOLUTION: A power semiconductor module 10 according to the present invention includes: a first terminal case 11f to which a first main terminal 12a1 that is an external terminal is screwed; a second terminal case 11g to which a second main terminal 12b1 that is an external terminal is screwed; a first main terminal wiring part 12a3 which is connected to the first main terminal 12a1; and a second main terminal wiring part 12b3 which is connected to the second main terminal 12b1. The first main terminal 12a1 overlaps the first main terminal wiring part 12a3 and the second main terminal wiring part 12b3 with the first terminal case 11f interposed therebetween. The first terminal case 11f has a bottom part 11f4 disposed between a screw hole for screwing the first main terminal 12a1 thereto and the first main terminal wiring part 12a3. The bottom part 11f4 has an arch-shaped recess 11f5 in the surface thereof on a side of the first main terminal wiring part 12a3.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a power semiconductor module equipped with a power semiconductor element, and a power conversion device using the same. [Background technology]

[0002] Patent Document 1 describes a semiconductor power module in which at least one of the main terminals (positive terminal, negative terminal, AC terminal) is configured to include two portions extending in a common direction (see abstract). Hereinafter, the "semiconductor power module" will be referred to as the "power semiconductor module."

[0003] In the power semiconductor module of Patent Document 1, the positive electrode terminal (11a) and the negative electrode terminal (11b) form an overlapping portion inside the module case (12) where the positive electrode terminal (11a) and the negative electrode terminal (11b) overlap, and are further arranged so that the negative electrode terminal (11b) overlaps this overlapping portion outside the module case (12) (see FIGS. 4, 8, 11, 12, and 15). Note that the parenthesized symbols used in the above description are symbols used in Patent Document 1 and differ from the symbols used in the examples of the present invention described below. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-119430 Summary of the Invention [Problem to be solved by the invention]

[0005] In the power semiconductor module of Patent Document 1, if a long screw is used to screw the negative terminal outside the module case to the module case, there is a risk that the screw may come into contact with the overlapping positive and negative terminals inside the module case. The proximity or contact between the positive and negative terminals inside the module case may cause insulation failure in the power semiconductor module.

[0006] An object of the present invention is to provide a power semiconductor module that is less likely to suffer from insulation failure. [Means for solving the problem]

[0007] In order to achieve the above object, the power semiconductor module of the present invention comprises: A power semiconductor module including: a first main terminal which is an external terminal; a second main terminal which is also an external terminal; a first terminal case to which the first main terminal is screwed; a second terminal case to which the second main terminal is screwed; a first main terminal wiring portion connected to the first main terminal; and a second main terminal wiring portion connected to the second main terminal, the first main terminal overlaps the first main terminal wiring portion and the second main terminal wiring portion with the first terminal case interposed therebetween; the first terminal case has a bottom portion disposed between a screw hole for screwing the first main terminal and the first main terminal wiring portion, The bottom portion has an arch-shaped recess on the surface on the side of the first main terminal wiring portion. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a power semiconductor module that is less likely to cause insulation defects, and thus to provide a highly reliable power conversion device.

[0009] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing the appearance of a power semiconductor module according to a first embodiment (Example 1) of the present invention. [Figure 2] 1 is an equivalent circuit diagram of a power semiconductor module according to a first embodiment of the present invention. [Figure 3] 1 is a perspective view showing the internal structure of a case of a power semiconductor module according to a first embodiment of the present invention. [Figure 4] 3A and 3B are diagrams illustrating the shape of a first main terminal of the power semiconductor module according to the first embodiment of the present invention. [Figure 5] 4A and 4B are diagrams showing the shape of a second main terminal of the power semiconductor module according to the first embodiment of the present invention. [Figure 6] 1 is a diagram schematically illustrating the configuration of a first main terminal and a first terminal case of a power semiconductor module according to a first embodiment of the present invention. [Figure 7] FIG. 10 is a diagram relating to a comparative example of the present invention, and is a diagram schematically illustrating the configuration of a first main terminal and a first terminal case. [Figure 8] FIG. 10 is a perspective view showing the internal structure of a case of a power semiconductor module according to a second embodiment (Example 2) of the present invention. [Figure 9] 1 is a perspective view showing the appearance of a power conversion device equipped with a semiconductor power module of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of a semiconductor power module according to the present invention and a power conversion device incorporating the same will be described with reference to the drawings.

[0012] [Example 1] Fig. 1 is a perspective view showing the appearance of a power semiconductor module 10 according to a first embodiment (Example 1) of the present invention. Fig. 2 is an equivalent circuit diagram of the power semiconductor module 10 according to the first embodiment of the present invention.

[0013] As shown in FIG. 1, a semiconductor power module 10 of this embodiment includes a case 11 that houses circuit components such as an IGBT chip (not shown), main terminals 12a1, 12b1, and 12c1 through which a large current flows, and low-voltage signal terminals 13a to 13h.

[0014] The case 11 includes a base portion 11a, a side wall portion 11b, and a lid portion 11c. The base portion 11a forms the bottom of the case 11, and the side wall portion 11b is provided so as to rise from the outer peripheral edge of the base portion 11a. Therefore, one end of the side wall portion 11b is closed by the base portion 11a, and the other end of the side wall portion 11b is open. The lid portion 11c is attached to the side wall portion 11b so as to cover the opening formed at the other end of the side wall portion 11b.

[0015] The case 11 accommodates a circuit including an equivalent circuit shown in Fig. 2. The equivalent circuit in Fig. 2 shows a current switch circuit for one phase among current switch circuits for generating three-phase (U-phase, V-phase, and W-phase) AC current. The current switch circuit 20 for one phase is configured as an upper and lower arm series circuit and includes a lower arm IGBT 21a, a lower arm diode 22a, an upper arm IGBT 21b, and an upper arm diode 22b. The lower arm IGBT 21a, the lower arm diode 22a, the upper arm IGBT 21b, and the upper arm diode 22b are circuit components configured from semiconductor elements.

[0016] The current switch circuit 20 is provided with the above-mentioned main terminals 12a1, 12b1, 12c1 and signal terminals 13a to 13h. The main terminals 12a1, 12b1, 12c1 and the signal terminals 13a to 13h are arranged to be exposed to the outside of the case 10 in order to electrically connect the current switch circuit 20 to external wiring.

[0017] The main terminals 12a1, 12b1, and 12c1 are composed of a first main terminal 12a1, a second main terminal 12b1, and a third main terminal 12c1. In this embodiment, the first main terminal 12a1 serves as the emitter terminal (negative terminal), the second main terminal 12b1 serves as the collector terminal (positive terminal), and the third main terminal 12c1 serves as the alternating current terminal (AC terminal).

[0018] The signal terminals 13a to 13h include a lower arm gate signal terminal 13a, a lower arm emitter signal terminal 13b, a lower arm collector signal terminal 13c, an upper arm gate signal terminal 13d, an upper arm emitter signal terminal 13e, an upper arm collector signal terminal 13f, a negative signal terminal 13g, and a temperature detection signal terminal 13h. The signal terminals 13a to 13g are terminals (control terminals) for signals that control the current switch circuit 20.

[0019] 1, the case 11 is formed so that its shape when viewed from the lid portion 11c is substantially rectangular, with the direction indicated by the arrow 10A as its longitudinal direction. The first main terminal 12b and the second main terminal 12a1 are arranged on one end face 11d in the longitudinal direction, and the third main terminal 12c1 is arranged on the other end face 11e opposite to the one end face 11d in the longitudinal direction. That is, the power semiconductor module 10 has a substantially rectangular shape, and the first main terminal 12a1 and the second main terminal 12b1 are arranged on one short side of the rectangular shape formed by the power semiconductor module 10, and the third main terminal 12c1 is arranged on the other short side. This allows all of the signal terminals 13a to 13h to be arranged together in the center of the case 11.

[0020] In this embodiment, the first main terminal 12a1 is disposed closer to the third main terminal 12c1 than the second main terminal 12b1, and is disposed closer to the center of the power semiconductor module 10 in the longitudinal direction of the power semiconductor module 10. Therefore, the signal terminals 13a to 13h are disposed between the first main terminal 12a1 and the third main terminal 12c1 in the longitudinal direction of the power semiconductor module 10.

[0021] The first main terminal 12a1, the second main terminal 12b1, and the third main terminal 12c1 are screwed to the lid portion 11c of the case 11. The first main terminal 12a1, the second main terminal 12b1, and the third main terminal 12c1 are exposed to the outside of the case 10 and are arranged to form external terminals to which external wiring is connected.

[0022] Furthermore, the signal terminals 13a to 13h may be fixed to the lid 11c of the case 11 by screws, but may also be fixed by a method of inserting into the lid 11c, such as a fasten terminal or a press-fit terminal.

[0023] Fig. 3 is a perspective view showing the internal structure of a case 11 of a power semiconductor module 10 according to a first embodiment of the present invention. Fig. 4 is a diagram showing the shape of a first main terminal of the power semiconductor module according to the first embodiment of the present invention. Fig. 5 is a diagram showing the shape of a second main terminal of the power semiconductor module according to the first embodiment of the present invention. Note that Fig. 3 is intended to show the configurations of first main terminal 12a1 and second main terminal 12b1, and does not show semiconductor elements and the like that constitute current switch circuit 20.

[0024] The first main terminal 12a1 is connected to the current switch circuit 20 housed inside the case 10 by first main terminal wiring portions 12a2 and 12a3 that extend toward the inside of the case 10. The first main terminal 12a1 and the first main terminal wiring portions 12a2 and 12a3 are formed by a single member, the first main terminal forming member 12a.

[0025] The second main terminal 12b1 is connected to the current switch circuit 20 housed inside the case 10 by second main terminal wiring portions 12b2 and 12b3 that extend toward the inside of the case 10. The second main terminal 12b1 and the second main terminal wiring portions 12b2 and 12b3 are formed by the single member, the second main terminal forming member 12b.

[0026] The first main terminal wiring portions 12a2, 12a3 have a vertically extending portion 12a2 extending from the first main terminal 12a1 toward the base portion 11a in a direction perpendicular to the component placement surface 11a1 of the base portion 11a, and a longitudinally extending portion 12a3 extending along the longitudinal direction 10A. The longitudinally extending portion 12a3 of the first main terminal wiring portions 12a2, 12a3 extends in the longitudinal direction from the end of the first main terminal 12a1 on the second main terminal 12b1 side toward the center of the power semiconductor module 10, i.e., toward the third main terminal 12c1 side.

[0027] The second main terminal wiring portions 12b2, 12b3 have a vertically extending portion 12b2 extending from the second main terminal 12b1 toward the base portion 11a in a direction perpendicular to the component placement surface 11a1 of the base portion 11a, and a longitudinally extending portion 12b3 extending along the longitudinal direction 10A. The longitudinally extending portion 12b3 of the second main terminal wiring portions 12b2, 12b3 extends in the longitudinal direction from the end of the second main terminal 12b1 on the first main terminal 12a1 side toward the center of the power semiconductor module 10, i.e., toward the third main terminal 12c1 side.

[0028] Note that longitudinal direction 10A coincides with the arrangement direction of first main terminal 12a1 and second main terminal 12b1, or the arrangement direction of first main terminal 12a1, second main terminal 12b1, and third main terminal 12c1.

[0029] The first main terminal 12a1, the longitudinally extending portions 12a3 of the first main terminal wiring portions 12a2 and 12a3, and the longitudinally extending portions 12b3 of the second main terminal wiring portions 12b2 and 12b3 overlap in the longitudinal direction 10A. As a result, the first main terminal 12a1 is arranged so as to overlap the longitudinally extending portions 12a3 of the first main terminal wiring portions 12a2 and 12a3 and the longitudinally extending portions 12b3 of the second main terminal wiring portions 12b2 and 12b3 in a direction perpendicular to the component placement surface 11a1 of the base portion 11a. In this case, the longitudinally extending portions 12a3 of the first main terminal wiring portion and the longitudinally extending portions 12b3 of the second main terminal wiring portion are arranged parallel to each other with a gap between them to maintain electrical insulation.

[0030] The longitudinally extending portions 12a3 of the first main terminal wiring portions 12a2, 12a3 are part of the first main terminal wiring portion, and hereinafter, the longitudinally extending portion 12a3 of the first main terminal wiring portion will be simply referred to as the "first main terminal wiring portion 12a3." Furthermore, the longitudinally extending portions 12b3 of the second main terminal wiring portions 12b2, 12b3 are part of the second main terminal wiring portion, and hereinafter, the longitudinally extending portion 12b3 of the second main terminal wiring portion will be simply referred to as the "second main terminal wiring portion 12b3."

[0031] The third main terminal 12c1 is arranged so as to be exposed to the outside of the case 10, and constitutes a terminal portion to which external wiring is connected. The third main terminal 12c1 is connected to the current switch circuit 20 housed inside the case 10 by a first main terminal wiring portion 12c2 that extends toward the inside of the case 10. The third main terminal 12c1 and the third main terminal wiring portion 12c2 are formed by a single member, the third main terminal forming member 12c.

[0032] Although the third main terminal wiring portion 12c2 of the third main terminal 12c1 has a bent portion in the middle, it extends in a direction substantially perpendicular to the component placement surface 11a1 of the base portion 11a, and is not configured to overlap with other wiring portions in the direction perpendicular to the component placement surface 11a1.

[0033] FIG. 6 is a diagram schematically showing the configuration of a first main terminal 11a and a first terminal case 11f of a power semiconductor module 10 according to a first embodiment of the present invention.

[0034] The lower arm IGBT 21 a, lower arm diode 22 a, upper arm IGBT 21 b, and upper arm diode 22 b that make up current switch circuit 20 are arranged on insulating substrate 18, and wiring between the components is performed by wires 16. Silicon gel 17 is poured inside case 11, and the electrical components and wires 16 arranged on insulating substrate 18 are embedded in silicone gel 17.

[0035] The first main terminal 12a1 is fixed to a first terminal case 11f made of resin. The first terminal case 11f is a box-shaped resin part and has a bottom 11f4 arranged between the first main terminal wiring part 12a3. The first terminal case 11f has a nut 14 built into a nut holding part 11f2 and is configured as one piece with the lid part 11c. The first terminal case 11f also has a screw storage part 11f3 that stores the tip of a screw 15 that passes through the nut 14, located closer to the bottom 11f4 than the nut holding part 11f2. The first terminal case 11f may be molded integrally with the lid part 11c, or may be configured to be attached to the lid part 11c.

[0036] The first terminal case 11f of this embodiment has a screw hole provided in the nut 14, but is not limited to a screw hole provided in the nut 14, as long as it has a screw hole for screwing the first main terminal 12a1.

[0037] The first main terminal 12a1 is disposed so as to abut against an upper end surface 11f1 (the end surface opposite to the lid portion 11c side) of the first terminal case 11f, and is fixed by threading a screw 15 into a nut 14. That is, the first main terminal 12a1 is screwed to the first terminal case 11f.

[0038] The second main terminal 12b1 is screwed to the resin second terminal case 11g in the same manner as the first main terminal 12a1. The third main terminal 12c1 is screwed to the resin third terminal case 11h in the same manner as the first main terminal 12a1.

[0039] The first main terminal 12a1 is arranged so as to overlap the first main terminal wiring portion 12a3 and the second main terminal wiring portion 12b3 in a direction perpendicular to the component placement surface 11a1 of the base portion 11a. In this case, the first main terminal wiring portion 12a3 and the second main terminal wiring portion 12b3 form an overlapping portion with a gap therebetween, and the first main terminal 12a1 is overlapped with this overlapping portion via the first terminal case 11f.

[0040] In this embodiment, an arch-shaped recess 11f5 is provided in the bottom 11f4 of the first terminal case 11f. That is, the bottom 11f4 of the first terminal case 11f has an arch-shaped recess 11f5 recessed toward the first main terminal 11a1 on the surface facing the first main terminal wiring portion 12a3 and the second main terminal wiring portion 12b3. The arch-shaped recess 11f5 forms a space 11f6 in the bottom 11f4 of the first terminal case 11f. The surface of the bottom 11f4 facing the screw hole, i.e., the surface facing the nut 14, is flat.

[0041] The bottom 11f4 of the first terminal case 11f has a thickness dA at the end of the arch-shaped recess 11f5 that is thicker than a thickness dB at the apex of the arch-shaped recess 11f5. In this embodiment, the arch-shaped recess 11f5 is formed in a tapered shape that narrows from the first main terminal wiring portion 12a3 side toward the first main terminal 12a1 side. The arch-shaped recess 11f5 is not limited to a tapered shape, and may be formed in a spherical shape that narrows from the first main terminal wiring portion 12a3 side toward the first main terminal 12a1 side. A recess with a depth (depth dimension) dC is formed at the apex of the arch-shaped recess 11f5.

[0042] Here, the problems associated with the overlapping structure of the first main terminal 12a1, the longitudinally extending portion 12a3 of the first main terminal wiring portion, and the longitudinally extending portion 12b3 of the second main terminal wiring portion will be described with reference to Fig. 7. Fig. 7 is a diagram of a comparative example to the present invention, and is a diagram schematically illustrating the configuration of the first main terminal 11a1 and the first terminal case 11f.

[0043] In the comparative example of FIG. 7, the bottom 11f4 of the first terminal case 11f does not have an arch-shaped recess 11f5 (see FIG. 6). In this case, if the first main terminal 12a1 is screwed to the first terminal case 11f using a screw longer than the specified length and the screw is tightened excessively, the bottom 11f4 of the first terminal case 11f may be deformed as shown by the dashed line 11f4'. This deformation of the bottom 11f4 causes it to protrude toward the first main terminal wiring portion 12a3 and the second main terminal wiring portion 12b3, and therefore it comes into contact with the first main terminal wiring portion 12a3 and presses the first main terminal wiring portion 12a3 toward the second main terminal wiring portion 12b3. If the deformation of the first main terminal wiring portion 12a3 pressed by the deformation of the bottom portion 11f4 exceeds the size of the gap set between the first main terminal wiring portion 12a3 and the second main terminal wiring portion 12b3 and further pushes out the silicone gel filled in this gap, the first main terminal wiring portion 12a3 will come close to or into contact with the second main terminal wiring portion 12b3, causing poor insulation.

[0044] During normal mass production, differentiated designated screws 15 are used, so such insulation defects are unlikely to occur. However, when testing the power semiconductor module 10, undesignated screws may be mixed in with the designated screws.

[0045] In this embodiment, an arch-shaped recess 11f5 is provided in the bottom 11f4 of the first terminal case 11f, and the arch-shaped recess 11f5 forms a space 11f6 in the bottom 11f4 of the first terminal case 11f, thereby increasing the distance from the bottom 11f4 of the first terminal case 11f to the first main terminal wiring portion 12a3. Therefore, even if a long screw 15' is mistakenly used and the screw 15' is overtightened, the space formed by the arch-shaped recess 11f5 makes it difficult for the bottom 11f4 of the first terminal case 11f to come into contact with the first main terminal wiring portion 12a3. As a result, deformation of the first main terminal wiring portion 12a3 due to the bottom 11f4 of the first terminal case 11f is suppressed, and contact between the first main terminal wiring portion 12a3 and the second main terminal wiring portion 12b3 is suppressed, thereby suppressing defects and insulation failures due to contact between the first main terminal wiring portion 12a3 and the second main terminal wiring portion 12b3. Furthermore, because the recess 11f5 is formed in an arch shape, the strength of the bottom 11f4 of the first terminal case 11f can be increased compared to a simple recess, and a decrease in strength compared to the bottom 11f4 without a recess can be suppressed, thereby also achieving the effect of suppressing deformation of the bottom 11f4.

[0046] [Example 2] FIG. 8 is a perspective view showing the internal structure of a case of a power semiconductor module according to a second embodiment (Example 2) of the present invention.

[0047] In the first embodiment, two each of the first main terminals 12a1, the second main terminals 12a2, and the third main terminals 12a3 are provided, but each of the first main terminals 12a1, the second main terminals 12a2, and the third main terminals 12a3 may be widened in a direction perpendicular to the longitudinal direction 10A, and one each may be provided.

[0048] In this case, by also widening the first main terminal wiring portion 12a3 extending from the first main terminal 12a1, it may be possible to reduce deformation when pressed by an incorrectly long screw 15'. Conversely, in the case of the first embodiment in which the first main terminal wiring portion 12a3 is composed of two narrow first main terminal wiring portions, the effect of providing the arch-shaped recess 11f5 in the bottom portion 11f4 of the first terminal case 11f is greater.

[0049] [Example 3] A power converter 100 equipped with a power semiconductor module 10 will be described with reference to Fig. 9. Fig. 9 is a perspective view showing the appearance of a power converter equipped with a semiconductor power module of the present invention. Fig. 9 shows an example in which the power semiconductor module 10 of the second embodiment in Fig. 8 is used. It goes without saying that the power semiconductor module 10 of the first embodiment may also be used in this embodiment.

[0050] 9 includes power semiconductor module 10 shown in the equivalent circuit of Fig. 2, DC bus bars 111a and 111b provided between first main terminal 12a1 and second main terminal 12b1 to connect a capacitor module, AC bus bar 112 provided to connect an induction motor to third main terminal 12c1, driver circuit board 131 provided above power semiconductor module 10 to drive power semiconductor module 10, and control device 132 to control driver circuit board 131. In power conversion device 100, power semiconductor module 10 is mounted on a heat sink 150 for the purpose of heat dissipation.

[0051] By mounting the power semiconductor module 10 of this embodiment, the occurrence of insulation failure in the power semiconductor module is suppressed, and the reliability of the power conversion device 100 is improved.

[0052] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0053] 10...power semiconductor module, 11f...first terminal case, 11f4...bottom of first terminal case 11f, 11f5...arch-shaped recess, 11g...second terminal case, 12a1...first main terminal, 12a3...first main terminal wiring section, 12b1...second main terminal, 12b3...second main terminal wiring section, 14...nut (screw hole), 131...driver circuit board, 132...control device, 150...heat sink, dA...thickness of end of arch-shaped recess 11f5, dB...thickness at apex of arch-shaped recess 11f5.

Claims

1. A power semiconductor module including: a first main terminal which is an external terminal; a second main terminal which is also an external terminal; a first terminal case to which the first main terminal is screwed; a second terminal case to which the second main terminal is screwed; a first main terminal wiring portion connected to the first main terminal; and a second main terminal wiring portion connected to the second main terminal, the first main terminal overlaps the first main terminal wiring portion and the second main terminal wiring portion with the first terminal case interposed therebetween; the first terminal case has a bottom portion disposed between a screw hole for screwing the first main terminal and the first main terminal wiring portion, The power semiconductor module, wherein the bottom portion has an arch-shaped recess on a surface on the side of the first main terminal wiring portion.

2. In claim 1, The power semiconductor module is characterized in that the thickness of the bottom is greater at the end than at the apex of the arch-shaped recess.

3. In claim 2, The power semiconductor module, characterized in that the arch-shaped recess has a tapered shape that reduces in diameter from the first main terminal wiring portion side toward the first main terminal side.

4. In any one of claims 1 to 3, The power semiconductor module is characterized in that the bottom has a flat surface on the side of the screw hole.

5. 4. A power conversion device comprising: a power semiconductor module according to claim 1; a heat sink for dissipating heat from the power semiconductor module; a driver circuit board for driving the power semiconductor module; and a control device for controlling the driver circuit board.

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