Power conversion device

Abstract

To provide a power conversion device in which stress at a time of mounting onto a water channel is reduced in a semiconductor module mounted on a main circuit printed board.SOLUTION: A power conversion device includes a plurality of semiconductor modules each including a semiconductor element and a terminal, a wiring board, and a heat dissipation member. A connection between the terminal and the wiring is disposed on a surface of the wiring board on which the heat dissipation member is disposed. The wiring board has a plurality of fixation portions. The plurality of semiconductor modules are arranged in a direction away from the respective fixation portions. The wiring board has a slit between the connection of the semiconductor module, of the plurality of semiconductor modules disposed on the wiring board, closest to the fixation portion and the fixation portion.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a power conversion device. [Background technology]

[0002] In addition to the demand for smaller size and lower profile, power conversion equipment also needs to be designed to be easier to produce. Therefore, by adopting a configuration that integrates the main circuit wiring in a printed circuit board, it is possible to omit joints, making it smaller, lower profile, and more productive. Accordingly, reliability of joints, etc. in the configuration of power conversion equipment is required.

[0003] The following Patent Document 1 discloses a semiconductor module that employs a configuration in which a heat-conducting part built into a through hole in a substrate has an overhanging part for the purpose of improving the heat dissipation of the element and making the amount of protrusion from the substrate constant, with respect to heat generated by the element. In this semiconductor module, the overhanging part is soldered to the wiring with the protrusion in contact with the wiring on the opposite side of the substrate, which has the advantage that the solder height (thickness of the solder layer) can be made uniform at the protruding part of the overhanging part. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-021817 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology of Patent Document 1, when a semiconductor module is assembled to a heat dissipation member, warping of the board and variations in the height of screw bosses during assembly cause plastic strain in the tensile direction at the solder joint. As a result, when multiple semiconductor modules each having multiple terminals are arranged side by side, it is difficult to make the fastening stress uniform at all terminals, which causes a problem of deteriorating the reliability of the solder joints of the power converter. In view of this, the present invention aims to provide a power converter that reduces the stress on a semiconductor module mounted on a main circuit printed circuit board during assembly to a water channel. [Means for solving the problem]

[0006] A power conversion device comprising: a plurality of semiconductor modules, each having a semiconductor element that converts DC power to AC power and a terminal connected to the semiconductor element; a wiring board having wiring electrically connected to the terminal; and a heat dissipation member in thermal contact with at least one surface of the semiconductor module, wherein a connection portion between the terminal and the wiring is provided on a surface of the wiring board on which the heat dissipation member is arranged, the wiring board has a plurality of fixing portions that fix the wiring board to the heat dissipation member, the plurality of semiconductor modules are arranged in a line on the wiring board in a direction away from each of the fixing portions, and the wiring board has a slit at a position between the fixing portion and the connection portion of the semiconductor module closest to the fixing portion among the plurality of semiconductor modules arranged on the wiring board. Effect of the Invention

[0007] It is possible to provide a power conversion device in which the stress on the semiconductor module mounted on the main circuit printed board during installation in the water channel is reduced. [Brief description of the drawings]

[0008] [Figure 1] 1 is an electrical circuit diagram of a power conversion device according to the present invention. [Diagram 2] 1 is a top view and an A-A′ cross-sectional view of a power conversion device for one phase according to an embodiment of the present invention. [Diagram 3] 1 is a perspective view of a power conversion device according to an embodiment of the present invention; FIG. [Figure 4] Figure 3 shows an overall perspective view and a top view of the heat dissipation component mounted.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0010] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0011] (One embodiment of the present invention and overall configuration) (Figure 1) The power conversion device 1 is composed of a plurality of semiconductor devices that perform power conversion across three phases, namely, U phase, V phase, and W phase. Each of the semiconductor devices includes an upper arm semiconductor element 4a and a lower arm semiconductor element 4b. For example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is used for the upper arm semiconductor element 4a and the lower arm semiconductor element 4b.

[0012] The upper arm semiconductor element 4a and the lower arm semiconductor element 4b are provided with three terminals: a high-voltage side terminal for the main circuit (a collector terminal for an IGBT, or a drain terminal for a MOSFET), a low-voltage side terminal for the main circuit (an emitter terminal for an IGBT, or a source terminal for a MOSFET), and a signal terminal (such as a gate terminal).

[0013] A plurality of upper-arm semiconductor elements 4a and lower-arm semiconductor elements 4b are formed and connected in parallel to each other, thereby increasing the output current of the power conversion device 1. In a power conversion circuit for one of the U-phase, V-phase, and W-phase, a capacitor 8 is paired with the upper-arm semiconductor element 4a and the lower-arm semiconductor element 4b that are connected in series. The capacitor 8 is, for example, a film capacitor or an electrolytic capacitor having a large capacitance. By arranging 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 for each phase.

[0014] The output wiring 6 of each phase is connected to a load such as a motor (not shown). The output wiring 6 also connects the upper arm semiconductor elements 4a and the lower arm semiconductor elements 4b. The positive wiring 2 is connected to the positive terminal of a DC power supply such as a battery (not shown), and the negative wiring 3 is connected to the negative terminal of the DC power supply such as a battery. This allows a DC voltage to be supplied to the semiconductor device (power conversion circuit) of each phase.

[0015] The positive terminals of the ceramic capacitor 7 and the film capacitor 8 are connected to the main circuit high-voltage side terminal of the upper arm semiconductor element 4a by a positive wiring 2. The negative terminals of the ceramic capacitor 7 and the film capacitor 8 are connected to the main circuit low-voltage side terminal of the lower arm semiconductor element 4b by a negative wiring 3.

[0016] 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 by 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 manner, a multi-phase circuit can be constructed.

[0017] The capacitor 8 is, for example, a film capacitor 8 with a large capacitance or a small ceramic capacitor 7, and by placing it in the vicinity of the upper arm semiconductor element 4a and the lower arm semiconductor element 4b, the wiring inductance of the positive wiring 2 and the negative wiring 3 can be reduced.

[0018] In the upper arm semiconductor element 4a and the lower arm semiconductor element 4b, signal terminals such as gate terminals are connected to a control circuit not shown, and are turned on or off based on a signal input from a higher-level control device such as a microcomputer, thereby outputting an AC voltage to a load such as a motor.

[0019] (Figure 2) Fig. 2(a) is a top view illustrating a power converter for one phase in which a plurality of semiconductor modules are connected to a wiring board, and Fig. 2(b) is a cross-sectional view taken along line A-A' of Fig. 2(a), showing an example of the configuration of an upper arm semiconductor module 20. In the plurality of semiconductor modules 20, 21, the aforementioned semiconductor elements 4a, 4b that convert DC power to AC power are sealed by a sealing member 17.

[0020] The power conversion device 1 includes a plurality of semiconductor modules 20, 21 each having the aforementioned semiconductor elements 4a, 4b that convert DC power into AC power and terminals connected to the semiconductor elements 4a, 4b, a wiring board 18 having wiring electrically connected to the terminals, and a heat dissipation member 16 in thermal contact with at least one surface of the semiconductor modules 20, 21. Connection portions 14 between the terminals of the semiconductor modules 20, 21 and the wiring of the wiring board 18 are provided on the surface of the wiring board 18 on which the heat dissipation member 16 is disposed.

[0021] The wiring board 18 has through holes 23 into which the semiconductor modules 20, 21 are inserted, and is connected to the semiconductor modules 20, 21 at the through holes 23. The wiring board 18 has signal wiring 15 that connects to a control terminal (signal terminal) 11 via a terminal connection portion 14 such as solder, and output wiring 6 that is a main circuit wiring that is 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, respectively, via the terminal connection portion 14 such as solder. The semiconductor elements 4a, 4b control the conduction between the main terminals based on a control signal applied to the control terminal 11. In the wiring board 18, the signal wiring 15 and the output wiring 6 that are connected to the upper arm semiconductor element 4a and the lower arm semiconductor element 4b via terminals are formed on the first layer of the board.

[0022] The positive electrode wiring 2, the negative electrode wiring 3, and the output wiring 6 formed on the first layer of the wiring board 18 are electrically connected to the other layers by interlayer connectors 19 formed by through-hole vias or the like. By providing a large number of interlayer connectors 19 on the wiring board 18, the cross-sectional area of ​​the current flowing in the cross-sectional direction of the wiring board 18 can be increased and the heat transfer in the cross-sectional direction of the wiring board 18 can be improved, thereby reducing electrical resistance and reducing heat generation in the board wiring, and suppressing an increase in the wiring temperature.

[0023] The wiring board 18 has a plurality of fixing portions 5 that fix the wiring board 18 to the heat dissipation member 16. The plurality of fixing portions 5 are, for example, screw fastening portions for fastening screws used as fixing members for fixing the wiring board 18 to the heat dissipation member 16. The fixing portions 5 are connected to the fixing members that fix the wiring board 18 to the heat dissipation member 16. The plurality of semiconductor modules 20, 21 are arranged side by side on the wiring board 18 in a direction away from the respective fixing portions 5.

[0024] In the semiconductor module 20, the connection portions 14 of the signal terminals 11 are provided on the surface on the side where the heat dissipation member 16 is arranged. Similarly, the connection portions 14 of the main terminals 9, 10 are also provided on the surface on the side where the heat dissipation member 16 is arranged. In the semiconductor module 20, the heat dissipation member 16 is in contact with the terminals 9, 10, 11 via the heat dissipation surface 16a. The semiconductor module 21 has the same configuration.

[0025] Furthermore, wiring board 18 has slits 5a, 5b at positions between fixed portion 5 and the connection portions of semiconductor modules 20, 21 that are closest to fixed portion 5 among the multiple semiconductor modules 20, 21 arranged on wiring board 18.

[0026] In the manufacturing process, the semiconductor modules 20, 21 are assembled to the wiring board 18 so that a compressive stress is generated in the terminal connection portion 14 when the semiconductor modules 20, 21 are pressed against the heat dissipation member 16 in a process after bonding to the wiring board 18.

[0027] This allows the stress generated in the solder of connection portion 14 to be compressive, reducing solder strain caused by tensile stress generated in a portion. Specifically, slits 5a and 5b ease the forced displacement that each terminal receives from fixed portion 5, suppressing excessive compressive stress generated in terminal connection portion 14 near each fixed portion 5, thereby reducing tensile stress in terminal connection portion 14 farthest from each fixed portion 5. This improves the reliability of the solder joints between semiconductor modules 20 and 21 and wiring board 18.

[0028] The following describes the slits 5a and 5b formed in the wiring board 18. The first slits 5a are formed in the wiring board 18 in a direction perpendicular to the direction in which the semiconductor modules 20 and 21 are arranged. On the other hand, the second slits 5b are formed in the wiring board 18 in parallel to the direction in which the semiconductor modules 20 and 21 are arranged.

[0029] The first slits 5a prevent an increase in inductance by not increasing (preventing interference) the current path from a capacitor (not shown) to the positive electrode wiring 2 and the negative electrode wiring 3. The second slits 5b prevent interference between the output wiring 6 (AC wiring) and the control circuit, and thus prevent an increase in inductance by not increasing the current path of the output wiring 6, and the control circuit (not shown) can be configured within the wiring board 18, thereby realizing a miniaturized power conversion circuit.

[0030] The wiring board 18 is attached to the heat dissipation member 16 arranged on the upper surface of the wiring board 18 by fastening a fixing member (not shown) to the fixing portion 5 which is an assembly hole of the heat dissipation member 16. The heat dissipation member 16 arranged on the lower surface of the wiring board 18 is attached by sandwiching the semiconductor modules 20, 21. At this time, the slits 5a formed in the wiring board 18 divert the stress that the terminals of the semiconductor modules 20, 21 receive at the shortest distance from the fixing portion 5, dispersing the stress, thereby mitigating the forced displacement. Therefore, the excessive compressive stress generated in the terminals of the semiconductor modules 20, 21 closest to the fixing portion 5 is suppressed, and the tensile stress of the terminal connection portion 14, especially the excessive tensile stress generated in the terminals farthest from each fixing portion 5, is reduced, improving the reliability of the solder joints.

[0031] In addition, by reducing distortion that occurs when the wiring board 18 is attached to the heat dissipation member 16, the reliability of the solder joints is improved, thereby extending the product life. By adopting such a configuration, multiple parallel mounting of the semiconductor modules 20 and 21 can be achieved, and also productivity can be improved and costs can be reduced.

[0032] Each of the semiconductor modules 20, 21 has a plurality of control terminals and a plurality of main terminals, and the plurality of semiconductor modules 20, 21 contact the heat dissipation member 16 on both sides in the thickness direction. As a result, the semiconductor modules 20, 21 incorporated in the through-hole 23 of the wiring board 18 can secure heat dissipation surfaces 16a on the top and bottom, and can realize double-sided cooling, which contributes to improving the heat dissipation performance of the power conversion device 1.

[0033] Although the above description has been given of the power conversion device 1 in which the slits 5a and 5b of the present invention are both formed in the wiring board 18, it is also possible to form only one of the slits 5a or slits 5b in the wiring board 18.

[0034] (Figure 3) Fig. 3(a) is an overall perspective view of the power conversion device 1, and Fig. 3(b) is an overall top view of the power conversion device 1. The multiple capacitors 8 are each connected to a positive electrode wiring 2 and a negative electrode wiring 3 provided on a wiring board 18, which is a control board. The positive electrode wiring 2 and the negative electrode wiring 3 have a DC input terminal 22, and conduct DC power input from a battery or the like (not shown) to the semiconductor modules 20, 21.

[0035] When the multiple capacitors 8 are of a type with large capacitance, such as a film capacitor 8, they are arranged in a line on the side of the wiring board 18 along the direction in which the three-phase semiconductor modules 20, 21 of the U phase, V phase, and W phase are arranged, which makes it easier to fix them to the case (not shown) of the power conversion device 1, and improves vibration resistance.

[0036] The upper arm semiconductor module 20 including the above-mentioned upper arm semiconductor element 4a and the lower arm semiconductor module 21 including the above-mentioned lower arm semiconductor element 4b each extend in a line from the capacitor 8 toward the output terminal 6a, thereby making it possible to shorten the length of the wiring of the positive electrode wiring 2, the negative electrode wiring 3, and the output wiring 6. This makes it easy to reduce the size of the power conversion device 1. This also contributes to reducing the size of the heat dissipation member 16, such as a cooler, that is attached from the outside, and facilitating its attachment.

[0037] (Figure 4) Fig. 4(a) is an overall perspective view of the power converter 1 described above in Fig. 3 with heat dissipation members 16 installed on both sides, and Fig. 4(b) is an overall top view of Fig. 4(a). Heat dissipation members 16 are arranged above and below the wiring board 18. This allows cooling on both sides of the multiple semiconductor modules 20, 21 arranged on the wiring board 18, improving heat dissipation performance.

[0038] According to the embodiment of the present invention described above, the following advantageous effects are obtained.

[0039] (1) A power conversion device 1 including a plurality of semiconductor modules 20, 21 each having semiconductor elements 4a, 4b for converting DC power to AC power and terminals connected to the semiconductor elements 4a, 4b, a wiring board 18 having wiring electrically connected to the terminals, and a heat dissipation member 16 in thermal contact with at least one surface of the semiconductor modules 20, 21, wherein a connection portion 14 between the terminals and the wiring is provided on a surface of the wiring board 18 on which the heat dissipation member 16 is arranged, the wiring board has a plurality of fixing portions 5 for fixing the wiring board 18 to the heat dissipation member 16, the plurality of semiconductor modules 20, 21 are arranged in a row on the wiring board 18 in a direction away from each fixing portion 5, and the wiring board 18 has slits 5a, 5b at a position between the fixing portion 5 and the connection portion 14 of the semiconductor module 20, 21 closest to the fixing portion 5 among the plurality of semiconductor modules 20, 21 arranged on the wiring board 18. By doing so, the stress on the semiconductor modules 20, 21 mounted on the main circuit printed board 18 during assembly to the heat dissipation member 16, which is a water channel, is reduced.

[0040] (2) The slits 5a are formed in the wiring board 18 in a direction perpendicular to the direction in which the semiconductor modules 20 and 21 are arranged. This prevents an increase in inductance.

[0041] (3) The slits 5b are formed in parallel to the direction in which the semiconductor modules 20, 21 are arranged in the wiring board 18. This makes it possible to prevent an increase in inductance and to realize a miniaturized power conversion circuit.

[0042] (4) Wiring board 18 has through holes 23 into which multiple semiconductor modules 20, 21 are inserted. This allows power conversion device 1 including wiring board 18 and semiconductor modules 20, 21 to be made smaller and thinner.

[0043] (5) The semiconductor modules 20 and 21 have a plurality of control terminals and a plurality of main terminals, and the semiconductor elements 4a and 4b control the conduction between the main terminals based on a control signal applied to the control terminals. In this manner, the power conversion device 1 converts DC power into AC power.

[0044] (6) The semiconductor modules 20, 21 are in contact with the heat dissipation member 16 on both sides in the thickness direction. This allows the power conversion device 1 to be cooled on both sides.

[0045] The present invention is not limited to the above-described embodiment, and various modifications and other configurations can be combined without departing from the spirit of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-described embodiment, and includes those in which some of the configurations are omitted. [Explanation of symbols]

[0046] 1 Power conversion device 2 Positive Wiring 3 Negative Wiring 4a Upper arm semiconductor element 4b Lower arm semiconductor element 5 Fixed part 5a First slit 5b Second slit 6 Output wiring 6a Output terminal 7. Ceramic Capacitors 8 Capacitors (film capacitors) 9 Low-voltage side terminal for main circuit of upper arm semiconductor element 10 High voltage side terminal for main circuit of upper arm semiconductor element 11 Control terminal 12 Low-voltage side terminal for main circuit of lower arm semiconductor element 13 High voltage side terminal for main circuit of lower arm semiconductor element 14 Terminal connection 15 Signal wiring 16 Heat dissipation material 16a Heat dissipation surface 17 Sealing member 18 Wiring board 19 Interlayer connection 20 Upper arm semiconductor module 21 Lower arm semiconductor module 22 DC input terminal

Claims

1. A plurality of semiconductor modules each having a semiconductor element that converts DC power into AC power and a terminal connected to the semiconductor element; a wiring board having wiring electrically connected to the terminals; A power conversion device comprising: a heat dissipation member in thermal contact with at least one surface of the semiconductor module, a connection portion between the terminal and the wiring is provided on a surface of the wiring board on which the heat dissipation member is disposed, the wiring board has a plurality of fixing portions for fixing the wiring board to the heat dissipation member, the plurality of semiconductor modules are arranged side by side on the wiring board in a direction away from the respective fixing portions, The wiring board has a slit between the fixing portion and the connection portion of the semiconductor module that is closest to the fixing portion among the plurality of semiconductor modules arranged on the wiring board. Power conversion equipment.

2. The power conversion device according to claim 1, The slits are formed in the wiring board in a direction perpendicular to a direction in which the semiconductor modules are arranged. Power conversion equipment.

3. The power conversion device according to claim 1, The slits are formed in the wiring board in parallel with a direction in which the semiconductor modules are arranged. Power conversion equipment.

4. The power conversion device according to claim 1, The wiring board has through holes into which the semiconductor modules are inserted. Power conversion equipment.

5. The power conversion device according to claim 1, the semiconductor module has a plurality of control terminals and a plurality of main terminals; The semiconductor element controls conduction between the main terminals based on a control signal applied to the control terminal. Power conversion equipment.

6. The power conversion device according to claim 1, The semiconductor modules are in contact with the heat dissipation member on both sides in a thickness direction. Power conversion equipment.

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