Power conversion device

Abstract

A power conversion device is provided with a plurality of semiconductor modules each having a semiconductor element and a terminal, a wiring substrate, and a heat dissipation member, in which a connection portion between the terminal and a wiring is provided on a surface of the wiring substrate on which the heat dissipation member is disposed, the wiring substrate having a plurality of fixing portions, the plurality of semiconductor modules are arranged in parallel in a direction away from the respective fixing portions, and the wiring substrate has a slit at a position between the connecting portion and the fixing portion. The connection portion is a connection portion of the semiconductor module closest to the fixing portion among the plurality of semiconductor modules disposed on the wiring substrate.

Description

TECHNICAL FIELD

[0001] The present application relates to a power conversion device. BACKGROUND

[0002] The power conversion device requires a method of production that is easier in addition to miniaturization and low profile. Therefore, by adopting a configuration that integrates the main circuit wiring in the printed board, the joint portion can be omitted, enabling miniaturization, low profile, and increased production rate. Consequently, in the configuration of the power conversion device, the reliability of the joint portion and the like is required.

[0003] In the following Patent Document 1, a semiconductor module is disclosed that, with the aim of improving the heat dissipation of the element while keeping the amount of protrusion from the board constant, adopts a configuration in which the heat conducting portion assembled in the through hole of the board has a protruding portion for the heat generated in the element. In this semiconductor module, in a state in which the protruding portion is soldered to the wiring of the opposite side of the surface of the board, since the protruding portion is soldered to the wiring, it has the advantage that the height of the solder (thickness of the solder layer) can be homogenized using the convex portion of the protruding portion.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-021817 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In the technology of Patent Document 1, when assembling the semiconductor module to the heat dissipation member, since the warping of the board or the height of the thread protrusion at the time of assembly produces a deviation, plastic deformation occurs in the solder joint portion in the tensile direction. Therefore, in the case of arranging a plurality of semiconductor modules having a plurality of terminals, it is difficult to make the fastening stress uniform on all of the terminals, and the problem of deteriorating the reliability of the solder joint portion of the power conversion device occurs. In view of this, the object of the present application is to provide a power conversion device that reduces the stress at the time of assembly to the waterway of a semiconductor module mounted on a main circuit printed board.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] A power conversion device includes a plurality of semiconductor modules each having a semiconductor element that converts direct-current power into alternating-current power and a terminal connected to the semiconductor element, a wiring substrate having a wiring electrically connected to the terminal, and a heat dissipation member in thermal contact with at least one face of the semiconductor module, wherein a connection portion of the terminal and the wiring is provided on a face of the wiring substrate on which the heat dissipation member is arranged, the wiring substrate has a plurality of fixing portions that fix the wiring substrate to the heat dissipation member, the plurality of semiconductor modules are arranged side by side on the wiring substrate in a direction away from the respective fixing portions, and the wiring substrate has a slit at a position between the connection portion and the fixing portion, the connection portion being a connection portion of the semiconductor module closest to the fixing portion among the plurality of semiconductor modules arranged on the wiring substrate.

[0011] Effects of the Invention

[0012] The present application can provide a power conversion device that reduces stress on semiconductor modules mounted on a main circuit printed substrate when assembled to a waterway. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a circuit diagram of the power conversion device of the present application

[0014] Figure 2 is a plan view and an A-A' cross-sectional view of a power conversion device of one embodiment of the present application.

[0015] Figure 3 is an overall perspective view and a plan view of a power conversion device of one embodiment of the present application.

[0016] Figure 4 is an overall perspective view and a plan view of a power conversion device of one embodiment of the present application. Figure 3 is an overall perspective view and a plan view of a power conversion device of one embodiment of the present application. DETAILED DESCRIPTION

[0017] Embodiments of the present application will be described below with reference to the drawings. The following description and drawings are provided to illustrate the present application and appropriate omission, simplification and abstraction are made for the sake of clarity. The present application can be implemented in other various modes. Each component can be singular or plural unless specifically limited. The following description is provided to illustrate the present application and appropriate omission, simplification and abstraction are made for the sake of clarity. The present application can be implemented in other various modes. Each component can be singular or plural unless specifically limited.

[0018] The position, size, shape, range, and the like of each component shown in the drawings are sometimes not actual ones in order to easily understand the present application. Thus, the present application is not necessarily limited to the position, size, shape, range, and the like disclosed in the drawings.

[0019] (One Embodiment of the Present Application and Overall Configuration)

[0020] Figure 1 )

[0021] The power conversion device 1 is configured by a plurality of semiconductor devices that perform power conversion over the three phases of the U phase, the V phase, and the W phase. Each semiconductor device includes an upper arm semiconductor element 4a and a lower arm semiconductor element 4b. The upper arm semiconductor element 4a and the lower arm semiconductor element 4b use, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (metal-oxide-semiconductor field-effect transistor) or the like.

[0022] On the upper arm semiconductor element 4a and the lower arm semiconductor element 4b, three terminals of a high-voltage side terminal for a main circuit (a collector terminal if an IGBT, a drain terminal if a MOSFET), a low-voltage side terminal for a main circuit (an emitter terminal if an IGBT, a source terminal if a MOSFET), and a signal terminal (a gate terminal or the like) are provided.

[0023] By forming a plurality of upper arm semiconductor elements 4a and lower arm semiconductor elements 4b and connecting them in parallel with each other, the output current of the power conversion device 1 is increased. In the power conversion circuit of any one of the U phase, the V phase, and the W phase, the upper arm semiconductor element 4a and the lower arm semiconductor element 4b that are connected in series are configured in pairs with a capacitor 8. The capacitor 8 is, for example, a thin film capacitor or an electrolytic capacitor or the like that has a large electrostatic capacity. By disposing such a capacitor 8 in the vicinity of the upper arm semiconductor element 4a and the lower arm semiconductor element 4b, the wiring inductance of the positive electrode wiring 2 and the negative electrode wiring 3 is reduced. In addition, a small ceramic capacitor 7 is connected in parallel in units of each phase.

[0024] The output wiring 6 of each phase is connected to a load such as a motor (not shown). In addition, the output wiring 6 is connected to a plurality of upper arm semiconductor elements 4a and a plurality of lower arm semiconductor elements 4b. The positive electrode wiring 2 is connected to a positive electrode terminal of a direct current power supply such as a storage battery (not shown), and the negative electrode wiring 3 is connected to a negative electrode terminal of the direct current power supply. Thus, a direct current voltage is supplied to the semiconductor device (power conversion circuit) of each phase.

[0025] The positive electrode terminals of the ceramic capacitor 7 and the thin film capacitor 8 are connected to the high-voltage side terminals for a main circuit of the upper arm semiconductor elements 4a via the positive electrode wiring 2. In addition, the negative electrode terminals of the ceramic capacitor 7 and the thin film capacitor 8 are connected to the low-voltage side terminals for a main circuit of the lower arm semiconductor elements 4b via the negative electrode wiring 3.

[0026] ​The main circuit low voltage side terminal of the upper arm semiconductor element 4a is connected to the main circuit high voltage side terminal of the lower arm semiconductor element 4b through the output wiring 6 of each phase. The positive electrode wiring 2 is connected to the positive electrode terminal of the capacitor 7 of the other phase and the main circuit high voltage side terminal of the upper arm semiconductor element 4a of the other phase. The negative electrode wiring 3 is connected to the negative electrode terminal of the capacitor 7 of the other phase and the main circuit low voltage side terminal of the lower arm semiconductor element 4b of the other phase. In this way, a multi-phase circuit can be constructed.

[0027] The capacitor 8 is, for example, a thin film capacitor 8 having a large electrostatic capacity or a small ceramic capacitor 7, and by being disposed in the vicinity of the upper arm semiconductor element 4a and the lower arm semiconductor element 4b, the wiring inductance of the positive electrode wiring 2 and the negative electrode wiring 3 can be reduced.

[0028] In the upper arm semiconductor element 4a and the lower arm semiconductor element 4b, the signal terminal such as the gate terminal is connected to a control circuit not shown, and is turned on or off in accordance with a signal input from a higher-level control device such as a microcomputer, whereby an alternating voltage is output to a load such as a motor.

[0029] ( Figure 2 )

[0030] Figure 2 (a) of FIG. 1 is a plan view of a one-phase power conversion device in which a plurality of semiconductor modules are connected to a wiring substrate, Figure 2 (b) of FIG. 1 is Figure 2 A-A' cross-sectional view of (a) of FIG. 1 is a configuration example of an upper arm semiconductor module 20. A plurality of semiconductor modules 20, 21 each seal the above-described semiconductor elements 4a, 4b that convert direct current power into alternating current power by a sealing member 17.

[0031] The power conversion device 1 includes a plurality of semiconductor modules 20, 21 having the above-described semiconductor elements 4a, 4b that convert direct current power into alternating current power and terminals connected to the semiconductor elements 4a, 4b, a wiring substrate 18 having wirings electrically connected to the terminals, and a heat dissipation member 16 in thermal contact with at least one face of the semiconductor modules 20, 21. The connection portions 14 of the terminals of the semiconductor modules 20, 21 and the wirings of the wiring substrate 18 are provided on the face of the wiring substrate 18 on which the heat dissipation member 16 is disposed.

[0032] The wiring substrate 18 has through holes 23 into which the plurality of semiconductor modules 20, 21 are inserted, and is connected to the semiconductor modules 20, 21 in the through holes 23. The wiring substrate 18 has signal wirings 15 connected to the control terminal (signal terminal) 11 via the terminal connection portions 14 of solder or the like, and output wirings 6 as main circuit wirings connected to the main terminals 9, 10 of the upper arm semiconductor element 4a and the main terminals 12, 13 of the lower arm semiconductor element 4b via the terminal connection portions 14 of solder or the like, respectively. The semiconductor elements 4a, 4b control conduction between the main terminals in accordance with a control signal applied to the control terminal 11. In the wiring substrate 18, the signal wirings 15 and the output wirings 6 connected to the upper arm semiconductor element 4a and the lower arm semiconductor element 4b via the terminals are formed on the first layer of the substrate.

[0033] The positive electrode wiring 2, the negative electrode wiring 3, and the output wiring 6 formed on the first layer of the wiring substrate 18 are electrically connected to another layer through interlayer connection portions 19 formed by via holes or the like. By providing a plurality of interlayer connection portions 19 on the wiring substrate 18, it is possible to increase the cross-sectional area of the current flowing in the cross-sectional direction of the wiring substrate 18, improve the heat transfer property in the cross-sectional direction of the wiring substrate 18, thus reduce the resistance, reduce the heat generation in the substrate wiring, and suppress the rise in the wiring temperature.

[0034] The wiring substrate 18 has a plurality of fixing portions 5 that fix the wiring substrate 18 to the heat dissipation member 16. The plurality of fixing portions 5 are, for example, screw fixing portions of fastening screws that serve as fixing members that fix the wiring substrate 18 and the heat dissipation member 16. The fixing portions 5 are connected to the fixing members that fix the wiring substrate 18 to the heat dissipation member 16. The plurality of semiconductor modules 20, 21 are arranged side by side on the wiring substrate 18 in a direction away from the respective fixing portions 5.

[0035] In the semiconductor module 20, the connection portions 14 of the signal terminal 11 are provided on the side on which the heat dissipation member 16 is arranged. Similarly, the connection portions 14 of the main terminals 9, 10 are also provided on the side on which the heat dissipation member 16 is arranged. In addition, the heat dissipation member 16 is in contact with the terminals 9, 10, 11 via the heat dissipation surface 16a in the semiconductor module 20. In addition, these are also similarly configured in the semiconductor module 21.

[0036] In addition, the wiring substrate 18 has slits 5a, 5b at positions between the connection portions of the semiconductor modules 20, 21 closest to the fixing portions 5 and the fixing portions 5 among the plurality of semiconductor modules 20, 21 arranged on the wiring substrate 18.

[0037] The semiconductor modules 20, 21 are assembled on the wiring substrate 18 in a manner that a stress in a compression direction is generated on the terminal connection portions 14 when the heat dissipation member 16 is pressed in a process after the semiconductor modules 20, 21 are joined to the wiring substrate 18 in a manufacturing process.

[0038] Thus, the stress generated on the solder of the terminal connecting portion 14 is mainly in the compression direction, and the deformation of the solder caused by the tensile stress generated in a portion can be reduced. Specifically, with respect to the forced displacement of each terminal from the fixing portion 5, the slits 5a, 5b function to moderate the stress, and the excessive compression stress generated on the terminal connecting portion 14 in the vicinity of each fixing portion 5 is suppressed, whereby the tensile stress of the terminal connecting portion 14 farthest from each fixing portion 5 can be reduced. Thus, the reliability of the solder joint of the semiconductor modules 20, 21 and the wiring substrate 18 is improved.

[0039] The plurality of slits 5a, 5b formed on the wiring substrate 18 will be described. The first slit 5a is formed on the wiring substrate 18 in a direction perpendicular to the direction in which the plurality of semiconductor modules 20, 21 are arranged. On the other hand, the second slit 5b is formed on the wiring substrate 18 in parallel with the direction in which the plurality of semiconductor modules 20, 21 are arranged.

[0040] The first slit 5a does not increase the current path from the capacitor not shown to the positive electrode wiring 2 and the negative electrode wiring 3 (prevents interference), thereby preventing an increase in inductance. In addition, the second slit 5b prevents interference of the output wiring 6 (AC wiring) with the control circuit, whereby since the current path of the output wiring 6 is not increased, an increase in inductance is prevented, and since the control circuit not shown can be constituted within the wiring substrate 18, miniaturization of the power conversion circuit can be achieved.

[0041] The wiring substrate 18 is mounted on the heat dissipation member 16 disposed on the upper surface of the wiring substrate 18 by fastening a fixing member not shown to the fixing portion 5 of the assembly hole of the heat dissipation member 16 as the heat dissipation member 16. In addition, the heat dissipation member 16 disposed on the lower surface of the wiring substrate 18 is mounted in a manner of sandwiching the semiconductor modules 20, 21. At this time, by the slit 5a formed on the wiring substrate 18, the stress of the terminals of the semiconductor modules 20, 21 subjected to the stress from the fixing portion 5 at the shortest distance is diverted through the slit 5a to disperse the stress, whereby the forced displacement is moderated. Therefore, the excessive compression stress generated on the terminals of the semiconductor modules 20, 21 closest to the fixing portion 5 can be suppressed, the tensile stress of the terminal connecting portion 14 is reduced, and in particular, the excessive tensile stress generated on the terminals farthest from each fixing portion 5 is reduced, and the reliability of the solder joint is improved.

[0042] In addition, by reducing the strain when the wiring substrate 18 is assembled to the heat dissipation member 16, product long life due to improvement in the reliability of the solder joint is achieved. By adopting such a configuration, the multi-parallel mounting of the semiconductor modules 20, 21 can be achieved, and in addition, the improvement in productivity and the reduction in cost can be achieved.

[0043] The semiconductor modules 20, 21 each have a plurality of control terminals and a plurality of main terminals, and the plurality of semiconductor modules 20, 21 are in contact with the heat dissipation member 16 on both surfaces in the thickness direction. Thus, the semiconductor modules 20, 21 assembled in the through holes 23 of the wiring substrate 18 can ensure the upper and lower heat dissipation surfaces 16a, and can achieve double-sided cooling, thus contributing to improvement of the heat dissipation performance of the power conversion device 1.

[0044] In addition, the power conversion device 1 in which the slits 5a, 5b are formed on the wiring substrate 18 has been described above, but either the slit 5a or the slit 5b can be formed on the wiring substrate 18.

[0045] ( Figure 3 )

[0046] Figure 3 (a) of FIG. 1 is a perspective view of the entire power conversion device 1, Figure 3 (b) of FIG. 1 is a plan view of the entire power conversion device 1. The plurality of capacitors 8 are connected to the positive electrode wiring 2 and the negative electrode wiring 3 provided on the wiring substrate 18 as a control substrate, respectively. The positive electrode wiring 2 and the negative electrode wiring 3 have direct current input terminals 22, and make the direct current power input from a battery or the like not shown conductive to the semiconductor modules 20, 21.

[0047] In the case of a type having a large electrostatic capacity such as a thin film capacitor 8, the plurality of capacitors 8 are arranged side by side in the wiring substrate 18 in the direction in which the semiconductor modules 20, 21 of the U-phase, the V-phase, and the W-phase are arranged, and thus are easily fixed to a housing (not shown) of the power conversion device 1, and the vibration resistance can be improved.

[0048] The upper arm semiconductor module 20 provided with the above-described upper arm semiconductor element 4a and the lower arm semiconductor module 21 provided with the above-described lower arm semiconductor element 4b can shorten the wiring lengths of the positive electrode wiring 2, the negative electrode wiring 3, and the output wiring 6 by extending in a row from the capacitors 8 to the output terminals 6a, respectively. Thus, the power conversion device 1 can be easily downsized. In addition, the heat dissipation member 16 such as a cooler mounted from the outside can be downsized and easily mounted.

[0049] ( Figure 4 )

[0050] Figure 4 (a) of FIG. 1 is a perspective view of the entire power conversion device 1, Figure 3 (b) of FIG. 1 is a plan view of the entire power conversion device 1. The plurality of capacitors 8 are connected to the positive electrode wiring 2 and the negative electrode wiring 3 provided on the wiring substrate 18 as a control substrate, respectively. The positive electrode wiring 2 and the negative electrode wiring 3 have direct current input terminals 22, and make the direct current power input from a battery or the like not shown conductive to the semiconductor modules 20, 21. Figure 4 Figure 4 ​An overall plan view of (a). The heat dissipation member 16 is arranged above and below the wiring substrate 18. Thus, the double-sided cooling of the plurality of semiconductor modules 20, 21 arranged on the wiring substrate 18 is enabled, and the heat dissipation performance is improved.

[0051] According to the one embodiment of the present application described above, the following effects are exerted.

[0052] (1) A power conversion device 1 includes a plurality of semiconductor modules 20, 21 having semiconductor elements 4a, 4b that convert direct-current power into alternating-current power and terminals connected to the semiconductor elements 4a, 4b, a wiring substrate 18 having wirings electrically connected to the terminals, and a heat dissipation member 16 in thermal contact with at least one face of the semiconductor modules 20, 21. In the power conversion device 1, a connection portion 14 of the terminals and the wirings is provided on a face of the wiring substrate 18 on which the heat dissipation member 16 is arranged, the wiring substrate has a plurality of fixing portions 5 that fix the wiring substrate 18 to the heat dissipation member 16, the plurality of semiconductor modules 20, 21 are arranged side by side on the wiring substrate 18 in a direction away from the respective fixing portions 5, and the wiring substrate 18 has slits 5a, 5b at positions between the connection portion 14 and the fixing portions 5. The connection portion 14 is a connection portion of the semiconductor module 20, 21 closest to the fixing portion 5 among the plurality of semiconductor modules 20, 21 arranged on the wiring substrate 18. Thus, stress at the time of assembly of the semiconductor modules 20, 21 mounted on the main circuit printed substrate 18 to the heat dissipation member 16 serving as a water passage is reduced.

[0053] (2) The slit 5a is formed in the wiring substrate 18 in a direction perpendicular to the direction in which the plurality of semiconductor modules 20, 21 are arranged. Thus, an increase in inductance is prevented.

[0054] (3) The slit 5b is formed in the wiring substrate 18 in parallel with the direction in which the plurality of semiconductor modules 20, 21 are arranged. Thus, an increase in inductance is prevented, and the power conversion circuit is miniaturized.

[0055] (4) The wiring substrate 18 has through-holes 23 into which the plurality of semiconductor modules 20, 21 are inserted. Thus, the power conversion device 1 including the wiring substrate 18 and the semiconductor modules 20, 21 can be miniaturized and thinned.

[0056] (5) The semiconductor modules 20, 21 have a plurality of control terminals and a plurality of main terminals, and the semiconductor elements 4a, 4b control conduction between the main terminals in accordance with a control signal applied to the control terminals. Thus, the power conversion device 1 converts direct-current power into alternating-current power.

[0057] (6) The plurality of semiconductor modules 20, 21 are in contact with the heat dissipation member 16 in the thickness direction on both sides. Thus, the power conversion device 1 can be double-sidedly cooled.

[0058] In addition, the present application is not limited to the above-described embodiments, and various modifications or other configurations can be combined within a scope without departing from the gist thereof. In addition, the present application is not limited to the structure provided with all the configurations described in the above-described embodiments, and includes a structure in which a part of the configurations is deleted.

[0059] Explanation of symbols

[0060] 1 power conversion device

[0061] 2 positive electrode wiring

[0062] 3 negative electrode wiring

[0063] 4a upper arm semiconductor element

[0064] 4b lower arm semiconductor element

[0065] 5 fixed portion

[0066] 5a first slit

[0067] 5b second slit

[0068] 6 output wiring

[0069] 6a output terminal

[0070] 7 ceramic capacitor

[0071] 8 capacitor (film capacitor)

[0072] 9 low-voltage side terminal for main circuit of upper arm semiconductor element

[0073] 10 high-voltage side terminal for main circuit of upper arm semiconductor element

[0074] 11 control terminal

[0075] 12 low-voltage side terminal for main circuit of lower arm semiconductor element

[0076] 13 high-voltage side terminal for main circuit of lower arm semiconductor element

[0077] 14 terminal connecting portion

[0078] 15 signal wiring

[0079] 16 heat dissipation member

[0080] 16a heat dissipation surface

[0081] 17 sealing member

[0082] 18 wiring substrate

[0083] 19 interlayer connecting portion

[0084] 20 upper arm semiconductor module

[0085] 21 lower arm semiconductor module

[0086] 22 DC input terminal.

Claims

1. A power conversion device comprising: a plurality of semiconductor modules having a semiconductor element that converts direct-current power into alternating-current power and a terminal connected to the semiconductor element; a wiring substrate having a wiring electrically connected to the terminal; and a heat dissipation member in thermal contact with at least one face of the semiconductor module, the power conversion device being characterized in that: a connection portion of the terminal and the wiring is provided on a face of the wiring substrate on which the heat dissipation member is disposed, the wiring substrate has a plurality of fixing portions that fix the wiring substrate to the heat dissipation member, the plurality of semiconductor modules are disposed side by side on the wiring substrate in a direction away from each of the fixing portions, and the wiring substrate has a slit at a position between the connection portion and the fixing portion, the connection portion being a connection portion of the semiconductor module closest to the fixing portion among the plurality of semiconductor modules disposed on the wiring substrate.

2. The power conversion device according to claim 1, characterized in that: the slit is formed on the wiring substrate in a direction perpendicular to a direction in which the plurality of semiconductor modules are arranged.

3. The power conversion device according to claim 1, characterized in that: the slit is formed on the wiring substrate in parallel with a direction in which the plurality of semiconductor modules are arranged.

4. The power conversion device according to claim 1, characterized in that: the wiring substrate has a through-hole into which the plurality of semiconductor modules are inserted.

5. The power conversion device according to claim 1, characterized in that: the semiconductor module has a plurality of control terminals and a plurality of main terminals, and the semiconductor element controls conduction between the main terminals in accordance with a control signal applied to the control terminals.

6. The power conversion device according to claim 1, characterized in that: the plurality of semiconductor modules contact the heat dissipation member with both faces in a thickness direction. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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