Power conversion device

Abstract

To achieve miniaturization, reduction in the number of assembly steps, improvement in cooling efficiency, and high output density in a power conversion apparatus in which a plurality of semiconductor modules are cooled by a cooler.SOLUTION: A cooler 6 cools a plurality of semiconductor modules 10a, 10b, and 10c. The plurality of semiconductor modules 10a, 10b, and 10c are disposed on the cooler 6. A fixing member 12 is disposed on the opposite side of the semiconductor modules 10a, 10b, and 10c from the cooler 6, and covers the plurality of semiconductor modules 10a, 10b, and 10c. Spring parts 7a, 7b, and 7c are insert-molded on a surface of the fixing member 12 on the semiconductor modules 10a, 10b, and 10c side and at positions overlapping the semiconductor modules 10a, 10b, and 10c. In the fixing member 12, openings 13a, 13b, and 13c are formed at positions overlapping the spring parts 7a, 7b, and 7c. The cooler 6 is fixed to a housing of a power conversion device, and the fixing member 12 is fixed to the housing of the power conversion device.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a technique for fixing a semiconductor module of a power converter, and more particularly to a technique for fixing a card-type semiconductor module to a heat sink (cooler). [Background technology]

[0002] In a typical inverter, a smoothing capacitor is connected to the DC input side, and a conductor is connected to the AC output side. A current sensor is often provided on the conductor to detect the current and control the inverter.

[0003] Conventionally, flat-type semiconductor modules with pin fins have been mainly used in inverters for vehicles, etc. In the future, card-type semiconductor modules are expected to become more popular in addition to the conventional flat-type semiconductor modules.

[0004] As shown in FIG. 1, the card-type semiconductor module has a module shape with a low height dimension, and each terminal (positive terminal 1, negative terminal 2, control terminal 3, AC terminal 4) protrudes from the side portion of the semiconductor module 10.

[0005] In such card-type semiconductor modules, the base plate of the semiconductor module must be tightly attached to and fixed to a heat sink (pin fin, comb-shaped, etc.) for cooling. Patent Document 1 discloses prior art for fixing a semiconductor module to a heat sink using spring parts. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-222069 Summary of the Invention [Problem to be solved by the invention]

[0007] One possible structure for using spring parts to closely attach a card-type power semiconductor to a heat sink is the configuration shown in Figure 2, which is an application of Patent Document 1. As shown in Figure 2, spring parts 7a, 7b, and 7c are fastened to the heat sink 6 with bolts 8. The pressure from the spring parts 7a, 7b, and 7c fixes the semiconductor modules 10a, 10b, and 10c in a pressed state against the heat sink 6.

[0008] The heat sink 6 is fixed to a housing (case) that houses the entire inverter circuit using the round holes 9 in FIG.

[0009] In this case, it is necessary to arrange spring parts 7a, 7b, and 7c for the semiconductor modules 10a, 10b, and 10c, respectively, which poses a problem in terms of miniaturizing the inverter and simplifying assembly.

[0010] Furthermore, in order to fix the spring parts 7a, 7b, and 7c, a female thread portion for receiving the bolt 8 is formed in the heat sink 6. This prevents the optimization of the flow path design when the heat sink 6 is a liquid-cooled type, increases the pressure loss of the refrigerant, and leads to a decrease in cooling performance.

[0011] As described above, in a power conversion device in which a plurality of semiconductor modules are cooled by a cooler, the challenges are to achieve miniaturization, reduction in the number of assembly steps, improvement in cooling efficiency, and high output density. [Means for solving the problem]

[0012] The present invention was devised in view of the above-mentioned problems of the conventional technology, and one aspect of the present invention comprises a cooler for cooling a plurality of semiconductor modules, a plurality of the semiconductor modules arranged on the cooler, a fixing member arranged on the opposite side of the semiconductor modules from the cooler and covering the plurality of semiconductor modules, and a spring portion insert-molded on the surface of the fixing member facing the semiconductor modules and at a position overlapping the semiconductor modules, wherein an opening is formed in the fixing member at the location overlapping with the spring portion, and the cooler is fixed to a housing of a power conversion device, and the fixing member is fixed to the housing of the power conversion device.

[0013] In one embodiment, the fixing member is provided with a fixing mechanism for fixing the substrate.

[0014] In one embodiment, the fixing member is made of resin.

[0015] In one embodiment, a conductor connected to an AC terminal of the semiconductor module and a current sensor for detecting a current flowing through the conductor are insert-molded into the fixing member.

[0016] In one embodiment, the fixing member is provided with a mechanism for fixing a smoothing capacitor.

[0017] In one embodiment, one positive terminal and one negative terminal of the smoothing capacitor are fixed to the positive and negative terminals of the semiconductor module by screws or welding. [Effects of the Invention]

[0018] According to the present invention, in a power conversion device in which a plurality of semiconductor modules are cooled by a cooler, it is possible to achieve miniaturization, reduction in the number of assembly steps, improvement in cooling efficiency, and high output density. [Brief explanation of the drawings]

[0019] [Figure 1]FIG. 1 is a schematic diagram showing a card-type semiconductor module. [Figure 2] 1 is a schematic diagram showing a conventional fixing structure between a card-type semiconductor module and a heat sink; [Figure 3] 1 is a perspective view showing a power conversion device according to a first embodiment. [Figure 4] FIG. 2 is an exploded view showing the power conversion device of the first embodiment. [Figure 5] FIG. 6 is a schematic diagram showing a power conversion device according to a second embodiment. [Figure 6] FIG. 10 is a schematic diagram showing a power conversion device according to a third embodiment. [Figure 7] FIG. 10 is a schematic view showing another example of the third embodiment. [Figure 8] FIG. 10 is a schematic diagram showing a power conversion device according to a fourth embodiment. [Figure 9] FIG. 10 is a schematic view showing another example of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, first to fourth embodiments of the power converter of the present invention will be described in detail with reference to FIGS.

[0021] [Embodiment 1] The configuration of the power conversion device (inverter) of the first embodiment is shown in Figures 3 and 4. Figure 3 is a perspective view of the power conversion device, and Figure 4 is an exploded view. As shown in Figures 3 and 4, three-phase semiconductor modules 10a, 10b, and 10c are arranged on a heat sink (cooler) 6 in the longitudinal direction of the heat sink 6. The heat sink 6 cools the multiple (three-phase) semiconductor modules 10a, 10b, and 10c.

[0022] The semiconductor modules 10a, 10b, and 10c are card-type power semiconductors and have a positive terminal 1, a negative terminal 2, an AC terminal 4, and a control terminal (not shown). The heat sink 6 is fixed to the housing (not shown) of the power conversion device with bolts 11.

[0023] In addition, upper arm switching elements such as IGBTs and lower arm switching elements are connected in series within the semiconductor modules 10a, 10b, and 10c. The collector terminals of the upper arm switching elements are connected to positive terminals 1 of the semiconductor modules 10a, 10b, and 10c. The emitter terminals of the lower arm switching elements are connected to negative terminals 2 of the semiconductor modules 10a, 10b, and 10c. The connection point between the emitter terminals of the upper arm switching elements and the collector terminals of the lower arm switching elements is connected to AC terminals 4 of the semiconductor modules 10a, 10b, and 10c. A three-phase inverter is configured by providing three such semiconductor modules 10a, 10b, and 10c.

[0024] The fixing member 12 is disposed on the opposite side of the semiconductor modules 10a, 10b, and 10c from the heat sink 6, and is formed in a substantially rectangular shape so as to cover the three semiconductor modules 10a, 10b, and 10c. Three spring portions (e.g., leaf springs) 7a, 7b, and 7c are inserted into the fixing member 12.

[0025] The spring portions 7a, 7b, and 7c are insert-molded on the surface of the fixing member 12 facing the semiconductor modules 10a, 10b, and 10c at positions that overlap the semiconductor modules 10a, 10b, and 10c.

[0026] Furthermore, openings 13a, 13b, and 13c are formed in the fixing member 12 at positions that overlap with the spring portions 7a, 7b, and 7c.

[0027] Spring portion 7a is fixed between one longitudinal end of fixing member 12 and two openings 13a, 13b. Spring portion 7b is fixed between openings 13a, 13b and between openings 13b, 13c of fixing member 12. Spring portion 7c is fixed between the other longitudinal end of fixing member 12 and openings 13b, 13c. Spring portions 7a, 7b, 7c are formed so as to protrude from the fixing portions at both ends toward the center toward semiconductor modules 10a, 10b, 10c. Although FIGS. 3 and 4 show spring portions 7a, 7b, 7c with a specific structure, other structures may be used as long as they are capable of applying a biasing force to semiconductor modules 10a, 10b, 10c.

[0028] The fixing member 12 is, for example, a molded product. The material of the fixing member 12 is not limited to resin, and any material can be used as long as it is capable of fixing the spring portion 7. However, using a non-metallic insulating material (for example, resin) makes it easier to design the insulation of the inverter, which is advantageous for miniaturization.

[0029] Bolt holes are formed in the four corners of the fixing member 12, and the fixing member 12 is fastened to the housing of the power conversion device by bolts 14. As a result, the spring portions 7a, 7b, and 7c that are insert-molded into the fixing member 12 are pressed against the semiconductor modules 10a, 10b, and 10c, deforming and generating a biasing force. The biasing force of the spring portions 7a, 7b, and 7c causes the semiconductor modules 10a, 10b, and 10c to be pressed against the heat sink 6 and fixed together.

[0030] Therefore, it is not necessary to form bolt holes for fixing the spring portions 7a, 7b, and 7c in the heat sink 6, and therefore it is not necessary to provide bolt fastening space between the semiconductor modules 10a, 10b, and 10c in the heat sink 6, which makes it possible to reduce the size of the heat sink 6 in the longitudinal direction. As a result, it is possible to reduce the size of the power conversion device (inverter).

[0031] Furthermore, because the spring portions 7a, 7b, and 7c are not fixed to the heat sink 6, there is no need for female threads for bolts to fix the spring portions 7a, 7b, and 7c to the heat sink 6. This allows for optimization of the flow path design when the heat sink 6 is of a liquid-cooled type, improving cooling performance.

[0032] Furthermore, instead of fixing the spring portions 7a, 7b, and 7c of each semiconductor module 10a, 10b, and 10c to the heat sink 6, the three-phase semiconductor modules 10a, 10b, and 10c are fixed together by the spring portions 7a, 7b, and 7c inserted into the fixing member 12, thereby reducing the number of screws, reducing the assembly man-hours, and making assembly easier. The fixing member 12 is fixed to the housing of the power conversion device at four points with bolts 14.

[0033] Furthermore, by forming openings 13a, 13b, and 13c at positions that overlap with spring portions 7a, 7b, and 7c of fixing member 12, when attaching heat sink 6 and fixing member 12 to the housing of the power conversion device, it becomes possible to visually check the degree of pressure of spring portions 7a, 7b, and 7c and whether or not there are any unexpected cracks, thereby reducing manufacturing defects.

[0034] Furthermore, the increased freedom in designing the semiconductor modules 10a, 10b, and 10c allows the power conversion device to have a higher output density.

[0035] Although Figures 3 and 4 show a configuration in which spring portions 7a, 7b, and 7c for three phases are inserted into the fixed member 12 at once, it is also possible to provide fixed members 12 for three phases, each with a spring portion 7 for one phase inserted therein.

[0036] As described above, according to the first embodiment, it is possible to achieve miniaturization (reducing the space between the semiconductor modules 10a, 10b, and 10c), reducing the number of assembly steps, improving cooling efficiency, reducing manufacturing defects, and increasing power density.

[0037] [Embodiment 2] The configuration of the power conversion device of the second embodiment is shown in Fig. 5. Fig. 5(a) is an exploded perspective view, and Fig. 5(b) is a perspective view after assembly. As shown in Fig. 5, a fixing mechanism for fixing a substrate 15 required for operating the semiconductor modules 10a, 10b, and 10c is provided on a fixing member 12.

[0038] The fixing mechanism is, for example, a screw hole 16 as shown in FIG. 5(a). The screw hole 16 is formed on the surface of the fixing member 12 opposite to the spring portions 7a, 7b, and 7c. The board 15 is fixed to the fixing member 12 by the screw 17 and the screw hole 16. The board 15 is, for example, a gate drive circuit for turning on and off the switching elements. The board 15 is connected to the control terminals of the semiconductor modules 10a, 10b, and 10c by a cable or the like.

[0039] As shown in Figure 5, adding a fixing mechanism for the board 15 to the fixing member 12 can further simplify assembly when incorporating it into the inverter. Also, screw fixing points can be installed in parts of the fixing member 12 other than the spring portions 7a, 7b, and 7c (openings 13a, 13b, and 13c), allowing the distance between fastening points to be set more precisely than before. This increases the degree of freedom in arranging the fixing points on the board 15, making it possible to improve vibration resistance.

[0040] [Embodiment 3] The configuration of the power conversion device of the third embodiment is shown in Fig. 6. Fig. 6(a) is a perspective view after assembly, and Fig. 6(b) is an exploded perspective view. As shown in Fig. 6, conductors 18a, 18b, and 18c connected to AC terminals 4a, 4b, and 4c of semiconductor modules 10a, 10b, and 10c, and a current sensor (current detection circuit) 19 that detects output current, are inserted into a fixing member 12.

[0041] Specifically, the fixing member 12 of the third embodiment has a shape that extends further in the protruding direction of the AC terminals 4a, 4b, and 4c of the semiconductor modules 10a, 10b, and 10c than the fixing member 12 of the first and second embodiments. The conductors 18a, 18b, and 18c and the current sensor 19 are fixed to the fixing member 12. The fixing positions of the conductors 18a, 18b, and 18c are positions that overlap with the AC terminals 4a, 4b, and 4c when the fixing member 12 is assembled. The fixing position of the current sensor 19 is disposed in a peripheral position (overlapping) with the conductors 18a, 18b, and 18c.

[0042] In this way, by insert-molding the conductors 18a, 18b, 18c that are connected to the AC terminals 4a, 4b, 4c of the semiconductor modules 10a, 10b, 10c and the current sensor 19 that detects the current in the conductors 18a, 18b, 18c into the molded fixing member 12, assembly can be further simplified when incorporating it into the inverter.

[0043] Although not shown in FIG. 6, current sensor 19 is provided with an output terminal (connector or the like) for transmitting a signal of the current detection value to a board shown in FIGS. 7 and 9 described later.

[0044] The parts manufacturer delivers an integrally molded product including the conductors 18a, 18b, and 18c and the current sensor 19 to the inverter manufacturer.

[0045] 6, by adding not only the insert for the spring portion 7 but also the functions of the conductors 18a, 18b, and 18c and the current sensor 19 to the AC terminals 4a, 4b, and 4c of the semiconductor modules 10a, 10b, and 10c in the fixing member 12, inverter manufacturers can simplify the parts assembly process. In addition, the integrated molding also has the effect of improving earthquake resistance.

[0046] Furthermore, while Figure 6 shows a configuration in which "conductors 18a, 18b, 18c and current sensor 19" are added to the configuration of embodiment 1, it is also possible to use a configuration in which "conductors 18a, 18b, 18c and current sensor 19" are added to the configuration in which substrate 15 of embodiment 2 is fixed, as shown in Figure 7.

[0047] As described above, according to the third embodiment, the conductors 18a, 18b, and 18c and the current sensor 19 are inserted into the fixing member 12 and integrally molded, thereby enabling miniaturization. Furthermore, inserting the conductors 18a, 18b, and 18c and the current sensor 19 into the fixing member 12 allows the inverter manufacturer to reduce assembly man-hours. Furthermore, since the fixing member 12, the conductors 18a, 18b, and 18c, and the current sensor 19 are integrally molded, it is possible to improve vibration resistance. Furthermore, the increased flexibility of the semiconductor modules 10a, 10b, and 10c allows the inverter unit to have a higher power density.

[0048] [Embodiment 4] The configuration of the power conversion device of the fourth embodiment is shown in Fig. 8. Fig. 8(a) is a perspective view after assembly, and Fig. 8(b) is an exploded perspective view. As shown in Fig. 8, a case for accommodating a smoothing capacitor 20 is provided on a fixing member 12.

[0049] Specifically, the fixing member 12 of the fourth embodiment has a shape that extends in the protruding direction of the positive electrode terminal 1 and the negative electrode terminal 2 of the semiconductor modules 10a, 10b, and 10c more than the fixing member 12 of the first and second embodiments. The extended portion of the fixing member 12 serves as a housing case for the smoothing capacitor 20.

[0050] By providing a mechanism for fixing (storing) the smoothing capacitor 20 connected to the positive electrode terminal 1 and the negative electrode terminal 2 of the semiconductor modules 10a, 10b, and 10c in the fixing member 12, the assembly process when incorporating the semiconductor modules into the inverter can be further simplified. In addition, the effect of improving earthquake resistance can be obtained by integral molding.

[0051] 8, fixing member 12 that holds semiconductor modules 10a, 10b, and 10c from above is integrally molded with the case of smoothing capacitor 20. Smoothing capacitor 20 is housed in the case, and the inside of the case is filled with resin.

[0052] The positive electrode terminal 21 and negative electrode terminal 22 on one side of the smoothing capacitor 20 are arranged in positions that coincide with the positive electrode terminal 1 and negative electrode terminal 2 of the semiconductor modules 10a, 10b, and 10c when the fixing member 12 is assembled to the semiconductor modules 10a, 10b, and 10c. During assembly, the positive electrode terminal 21 and negative electrode terminal 22 of the smoothing capacitor 20 are fixed to the positive electrode terminal 1 and negative electrode terminal 2 of the semiconductor modules 10a, 10b, and 10c, respectively, by screw fastening or welding. The positive electrode terminal 23 and negative electrode terminal 24 on the other side of the smoothing capacitor 20 are connected to a DC power source such as a battery.

[0053] The parts manufacturer delivers the integrally molded product equipped with the smoothing capacitor 20 to the inverter manufacturer.

[0054] 8, inverter manufacturers can simplify the parts assembly process by adding a fixing mechanism for smoothing capacitor 20 to the positive terminal 1 and negative terminal 2 sides of semiconductor modules 10a, 10b, and 10c in addition to inserting spring portion 7 to fixing member 12. In addition, integral molding also has the effect of improving earthquake resistance.

[0055] Furthermore, in the configuration of the fourth embodiment, the positive terminal 21 and negative terminal 22 on one side of the smoothing capacitor 20 can be directly screwed to the positive terminal 1 and negative terminal 2 of the semiconductor modules 10a, 10b, and 10c. This reduces the inductance of the wiring between the smoothing capacitor 20 and the semiconductor modules 10a, 10b, and 10c, and reduces the surge voltage when the semiconductor modules 10a, 10b, and 10c are turned off. This makes the semiconductor modules 10a, 10b, and 10c less susceptible to overvoltage breakdown.

[0056] 8 shows a configuration in which a "smoothing capacitor fixing mechanism" is added to the configuration of embodiment 1, but a configuration in which a "smoothing capacitor fixing mechanism" is added to the configuration in which the substrate 15 of embodiment 2 is fixed, as shown in FIG. 9. Furthermore, although not shown, embodiment 4 may be applied to embodiment 3.

[0057] As described above, according to the fourth embodiment, by providing the fixing mechanism for the smoothing capacitor 20 to the fixing member 12, it is possible to reduce the size of the inverter and the number of assembly steps required by the inverter manufacturer. Furthermore, since it is integrally molded, it is possible to improve vibration resistance. Furthermore, by increasing the degree of freedom of the semiconductor modules 10a, 10b, and 10c, it is possible to achieve a high output density of the inverter unit.

[0058] It is also expected that the inductance of the wiring between the smoothing capacitor and the power module will be reduced, which will result in lower surge voltages in power semiconductors and suppression of overvoltage breakdown.

[0059] Although the present invention has been described in detail above only with respect to the specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope of the technical concept of the present invention, and it is natural that such modifications and variations fall within the scope of the claims.

[0060] In the first to fourth embodiments, a three-phase inverter is used, which has three semiconductor modules 10a, 10b, and 10c. The present invention is a technology that can be applied to any power conversion device that cools multiple semiconductor modules with a heat sink 6, such as a single-phase inverter with two semiconductor modules. [Explanation of symbols]

[0061] 1...Positive terminal 2...Negative terminal 3...Control terminal 4…AC terminal 6...Heat sink (cooler) 7a, 7b, 7c...Spring part (spring parts) 8...Bolt 9...Round hole 10a, 10b, 10c...Semiconductor modules 11...Bolt 12...Fixing member 13a, 13b, 13c...opening 14...Volts 15... Circuit board 16…Fixing mechanism (screw hole) 17...Screw 18a, 18b, 18c...conductor 19...Current sensor (current detection circuit) 20...Smoothing capacitor 21...Positive terminal 22...Negative terminal 23...Positive terminal 24...Negative terminal

Claims

1. a cooler for cooling the semiconductor modules; a plurality of the semiconductor modules arranged on the cooler; a fixing member that is disposed on the opposite side of the cooler from the semiconductor modules and covers the plurality of semiconductor modules; a spring portion that is insert-molded on a surface of the fixing member that faces the semiconductor module and at a position that overlaps the semiconductor module; Equipped with The fixing member has an opening formed at a location where the fixing member overlaps the spring portion, a power conversion device, characterized in that the cooler is fixed to a housing of the power conversion device, and the fixing member is fixed to the housing of the power conversion device.

2. 2. The power conversion device according to claim 1, further comprising a fixing mechanism for fixing the substrate to the fixing member.

3. 2. The power converter according to claim 1, wherein the fixing member is made of resin.

4. 2. The power conversion device according to claim 1, wherein a conductor connected to an AC terminal of the semiconductor module and a current sensor for detecting a current flowing through the conductor are insert-molded into the fixing member.

5. 2. The power conversion device according to claim 1, further comprising a mechanism for fixing a smoothing capacitor to the fixing member.

6. 6. The power conversion device according to claim 5, wherein one positive terminal and one negative terminal of the smoothing capacitor are fixed to the positive and negative terminals of the semiconductor module by screws or welding.

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