JP2016073086A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device capable of increasing rigidity of a case, and reducing inductance parasitic to a DC bus bar.SOLUTION: A power conversion device comprises a structure 10 composed of a semiconductor module 2 and a cooler 3, a pressure member 4, a pair of DC bus bars 6 (6p, 6n), and a case 5. The pressure member 4 brings the semiconductor module 2 and the cooler 3 into close contact by pressurizing the structure 10. The structure 10, the pressure member 4, and the DC bus bars 6 are interposed between a pair of pressed wall parts 51 and 52 constituting the case 5. Welding pressure F of the pressure member 4 is applied to the pair of pressed wall parts 51 and 52. A reinforcement rib 53 connecting the pair of pressed wall parts 51 and 52 is formed in the case 5. The reinforcement rib 53 is provided between the pair of DC bus bars 6. An insulating layer 7 for insulating these is interposed between the DC bus bars 6 and the reinforcement rib 53.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power conversion device including a semiconductor module incorporating a semiconductor element, a pair of DC bus bars connected to the semiconductor module, and a case for housing them.

  2. Description of the Related Art As a power conversion device that performs power conversion between DC power and AC power, a device that includes a semiconductor module incorporating a semiconductor element and a pair of DC bus bars connected to the semiconductor module is known (the following patent document) 1). This power converter is configured to convert DC power supplied from a DC power source through the pair of DC bus bars into AC power by switching the semiconductor module.

  The pair of DC bus bars are arranged to face each other, and are held while providing an insulating gap therebetween. By bringing these pair of DC bus bars as close as possible to each other, inductance parasitic on the DC bus bar is reduced.

  The semiconductor module and the DC bus bar are housed in a case together with a cooler for cooling the semiconductor module and a pressure member such as a leaf spring. With this pressurizing member, the laminated body of the semiconductor module and the cooler is pressed against the wall of the case and fixed. Thereby, the semiconductor module and the cooler are brought into close contact with each other to increase the cooling efficiency of the semiconductor module.

  If the said pressurization member is used, the pressurizing force of a pressurization member will be added to the wall part of a case. For this reason, the case is required to have high rigidity so as not to be deformed by the applied pressure.

JP 2011-114193 A

  However, in the power conversion device, it cannot be said that the case has sufficient rigidity with respect to the pressing force of the pressing member. Therefore, there is a demand for a power conversion device including a case that is more rigid and difficult to deform.

  Further, as described above, in the power conversion device, a pair of DC bus bars are arranged opposite to each other and are brought close to each other in order to reduce inductance. As the distance between the DC bus bars is narrower, the inductance can be reduced. However, in the power converter, the DC bus bars are insulated from each other by providing the gap between the pair of DC bus bars. Therefore, if the interval between the DC bus bars is too narrow, the DC bus bars may swing and come into contact with each other when vibration is transmitted from the outside. Therefore, the power converter has a limit in narrowing the interval between the DC bus bars, and there is a problem that the inductance cannot be sufficiently reduced.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a power conversion device that can increase the rigidity of a case and can further reduce inductance parasitic on a DC bus bar.

One embodiment of the present invention is a structure including a semiconductor module including a semiconductor element and a cooler that cools the semiconductor module;
A pair of direct current busbars connected to the semiconductor module, forming a direct current path between the direct current power source and the semiconductor element, and facing each other;
A case for housing the structure and the pair of DC bus bars;
A pressure member that is housed in the case and pressurizes the structure to fix the structure in the case and to bring the semiconductor module and the cooler into close contact with each other;
The structure, the pressure member, and the pair of DC bus bars are interposed between a pair of pressurized walls that are opposed to each other among the walls constituting the case, and the pressure of the pressure member is Participating in the pair of pressurized walls,
A reinforcing rib that connects the pair of pressurized walls is formed in the case,
The reinforcing rib is provided between the pair of DC bus bars, and an insulating layer that insulates the DC bus bar and the reinforcing rib is interposed between the reinforcing ribs.

  In the power converter, a reinforcing rib that connects the pair of pressurized walls is provided in the case. Therefore, the rigidity of the case can be increased, and deformation of the case due to the pressure applied by the pressure member can be suppressed.

Moreover, in the power converter, the reinforcing rib is provided between the pair of DC bus bars. An insulating layer is provided between the DC bus bar and the reinforcing rib to insulate them.
Therefore, even if a pair of DC bus bars swings due to external vibration, the reinforcing ribs and the insulating layer are provided between them, so that the DC bus bars can be prevented from contacting each other. Therefore, the interval between the DC bus bars can be narrowed and the inductance parasitic on the DC bus bar can be reduced as compared with the conventional case where a gap is simply provided between the pair of DC bus bars.

  As described above, according to the present invention, it is possible to provide a power converter that can increase the rigidity of the case and reduce the inductance parasitic on the DC bus bar.

It is sectional drawing of the power converter device in Example 1, Comprising: II sectional drawing of FIG. II-II sectional drawing of FIG. III-III sectional drawing of FIG. IV-IV sectional drawing of FIG. FIG. 3 is a perspective view of a DC bus bar in the first embodiment. The principal part enlarged view of FIG. VII-VII sectional drawing of FIG. FIG. 3 is an exploded perspective view of the case in the first embodiment. The circuit diagram of the power converter device in Example 1. FIG. The expanded sectional view of the power converter device in Example 2. FIG. FIG. 13 is an enlarged cross-sectional view of the power conversion device according to the third embodiment, which is a cross-sectional view taken along the line XI-XI in FIG. 12. FIG. 11 is an XII arrow view of FIG.

  The power conversion device can be a vehicle-mounted power conversion device mounted on a vehicle such as an electric vehicle or a hybrid vehicle.

Example 1
The Example which concerns on the said power converter device is described using FIGS. As shown in FIGS. 1 to 4, the power conversion device 1 of this example includes a structure 10 including a semiconductor module 2 and a cooler 3, a pressure member 4, and a pair of DC bus bars 6 (6 p and 6 n). And a case 5 for storing them.

  The semiconductor module 2 includes a semiconductor element 20 (see FIG. 9). The cooler 3 cools the semiconductor module 2. The DC bus bar 6 is connected to the semiconductor module 2 and forms a DC current path between the DC power supply 8 (see FIG. 9) and the semiconductor element 20. The pair of DC bus bars 6 are arranged to face each other. The pressing member 4 presses the structure 10. Thereby, the structure 10 is fixed in the case 5 and the semiconductor module 2 and the cooler 3 are brought into close contact with each other.

  The structure 10, the pressing member 4, and the pair of DC bus bars 6 are interposed between a pair of pressed wall portions 51 and 52 that face each other among the wall portions that form the case 5. The pressing member 4 presses the structure 10 in the wall thickness direction (X direction) of the pressed wall portions 51 and 52. A pressing force F of the pressing member 4 is applied to the pair of pressed wall portions 51 and 52.

A reinforcing rib 53 that connects the pair of pressurized wall portions 51 and 52 is formed in the case 5.
As shown in FIGS. 6 and 7, the reinforcing rib 53 is provided between the pair of DC bus bars 6. An insulating layer 7 is interposed between the DC bus bar 6 and the reinforcing rib 53 to insulate them.

  The power conversion device 1 of this example is a vehicle-mounted power conversion device to be mounted on a vehicle such as an electric vehicle or a hybrid vehicle.

  As shown in FIG. 9, the power conversion device 1 of this example includes a plurality of semiconductor modules 2. An inverter circuit 200 is configured by the semiconductor element 20 (IGBT element) built in the semiconductor module 2. Further, the power conversion device 1 of this example includes a capacitor 11. The capacitor 11 smoothes the DC voltage of the DC power supply 8. The semiconductor element 20 is switched to convert DC power into AC power, and the three-phase AC motor 81 is driven using the obtained AC power. As a result, the vehicle is running.

  As shown in FIG. 4, in this example, a plurality of semiconductor modules 2 and a plurality of cooling pipes 30 are stacked. The cooler 3 is configured by a plurality of cooling pipes 30. The case 5 includes a first pressurized wall portion 51 and a second pressurized wall portion 52. A pressure member 4 (plate spring) is disposed between the first pressure wall 51 and the structure 10. The structure 10 is pressed against the second pressed wall portion 52 by the pressing member 4. Thereby, the structure 10 is fixed in the case 5 while ensuring a contact pressure between the cooling pipe 30 and the semiconductor module 2.

  As shown in FIG. 2, each individual semiconductor module 2 includes a main body 21 containing the semiconductor element 20, a power terminal 22 protruding from the main body 21, and a control terminal 23. The power terminal 22 includes a positive terminal 22 p and a negative terminal 22 n to which a DC voltage is applied, and an AC terminal 22 c connected to the three-phase AC motor 81. The DC bus bar 6 is connected to the positive terminal 22p and the negative terminal 22n. An AC bus bar 131 is connected to the AC terminal 22c.

  The control terminal 23 is connected to the control circuit board 18. This control circuit board 18 causes the semiconductor element 20 to perform a switching operation. As a result, the DC power supplied from the positive terminal 22p and the negative terminal 22n is converted into AC power and output from the AC terminal 22c.

  As shown in FIGS. 6 and 7, the DC bus bar 6 includes a positive bus bar 6 p that forms a current path between the positive electrode 801 of the DC power supply 8 (see FIG. 9) and the semiconductor module 2, and a negative electrode of the DC power supply 8. There is a negative electrode bus bar 6 n that forms a current path between 802 and the semiconductor module 2. The positive electrode bus bar 6p and the negative electrode bus bar 6n are formed integrally with electrode plates 113 and 114 (see FIG. 3) of the capacitor 11, which will be described later.

  Further, the reinforcing rib 53 is arranged between the positive terminal 22p and the negative terminal 22n. The insulating layer 7 is adhered to the surface of the reinforcing rib 53 by an adhesive layer 71. The insulating layer 7 in this example is made of an insulating resin such as an epoxy resin. Further, the reinforcing rib 53 is formed in a plate shape. The DC bus bar 6 (6p, 6n) is provided at a position where the reinforcing rib 53 is sandwiched from the thickness direction (Y direction) of the reinforcing rib 53. The DC bus bar 6 is in contact with the insulating layer 7.

  As shown in FIG. 5, the DC bus bar 6 includes a bus bar main body portion 61 formed in a plate shape, a U-shaped portion 63, a sub-plate portion 620, and a plurality of terminal portions 62 (62 a to 62 c). The U-shaped portion 63 is connected to the bus bar main body portion 61 and straddles the first pressurized wall portion 51 (see FIG. 3).

  The sub plate portion 620 is arranged in parallel to the bus bar main body portion 61. Further, the terminal part 62 is connected to the semiconductor module 2. The bus bar main body portion 61, the U-shaped portion 63, the sub plate portion 620, and the terminal portion 62 are formed of a single metal plate.

  The bus bar main body 61 extends in the X direction. Among the plurality of terminal portions 62 (62a to 62c), some of the terminal portions 62a extend from the bus bar main body portion 61 in the Y direction. Further, the other part of the terminal portions 62b and 62c extends from the sub plate portion 620 in the Y direction. As shown in FIG. 7, the terminal portion 62 is superimposed on the power terminal 22. And the end surface 625 of the terminal part 62 and the front end surface 220 of the power terminal 22 are welded.

  As shown in FIG. 8, the case 5 includes a sidewall portion 55, an inner wall portion 56, a bottom wall portion 57, and a reinforcing wall portion 54 in addition to the pressurized wall portions 51 and 52. Case 5 is made of metal. The reinforcing rib 53 is formed integrally with the case 5.

  The second pressed wall portion 52 includes an inner wall portion 52a and an outer wall portion 52b. A through hole 520 that penetrates in the X direction is formed in the inner wall portion 52a. The through hole 520 is closed by the outer wall portion 52b.

  The reinforcing wall portion 54 further increases the rigidity of the case 5 and suppresses deformation of the case 5. A plurality of reinforcing wall portions 54 are formed. As shown in FIG. 2, the interval L between the reinforcing wall portions 54 a and 54 b in the Y direction is shorter than the length of the cooling pipe 30 in the Y direction. Therefore, when manufacturing the power converter 1, the cooling pipe 30 is moved in the protruding direction (Z direction) of the power terminal 22 and the cooling pipe 30 is moved from the gap G between the reinforcing wall portions 54a and 54b to the case 5. Cannot be inside. Therefore, in this example, the through hole 520 (see FIG. 8) is formed in the inner wall portion 52a. When the power conversion device 1 is manufactured, the cooling pipe 30 is moved in the X direction so that the cooling pipe 30 is accommodated in the case 5.

  As shown in FIG. 4, the two cooling pipes 30 adjacent to each other in the X direction are connected by connecting pipes 17 at both ends in the Y direction. In addition, among the plurality of cooling pipes 30, an end cooling pipe 30 a positioned at one end in the X direction includes an introduction pipe 14 for introducing the refrigerant 16 and an outlet pipe 15 for leading out the refrigerant 16. Connected. When the refrigerant 16 is introduced from the introduction pipe 14, the refrigerant 16 flows through all the cooling pipes 30 through the connection pipe 17 and is led out from the lead-out pipe 15. Thereby, the semiconductor module 2 is cooled.

  As shown in FIG. 1, the power conversion device 1 of this example includes an input terminal 12 and an output terminal 13. These input terminal 12 and output terminal 13 are placed on a terminal block 19. The input terminal 12 is connected to a DC power supply 8 (see FIG. 9), and the output terminal 13 is connected to a three-phase AC motor 81.

  As shown in FIG. 3, the capacitor 11 of this example includes a capacitor element 111, a sealing member 112 that seals the capacitor element 111, and electrode plates 113 and 114 connected to the capacitor element 111. The electrode plates 113 and 114 are formed integrally with the DC bus bar 6 and the input terminal 12.

  The effect of this example will be described. In this example, as shown in FIGS. 6 and 7, a reinforcing rib 53 that connects the pair of pressurized wall portions 51 and 52 is provided in the case 5. Therefore, the rigidity of the case 5 can be increased, and the case 5 can be prevented from being deformed by the pressing force of the pressure member 4.

In this example, the reinforcing rib 53 is provided between the pair of DC bus bars 6. An insulating layer 7 is provided between the DC bus bar 6 and the reinforcing rib 53 to insulate them.
For this reason, even if the pair of DC bus bars 6 (6p, 6n) swings due to external vibration, the reinforcing rib 53 and the insulating layer 7 are provided between them, so the pair of DC bus bars 6 (6p, 6n). ) Can be prevented from contacting each other. Therefore, the distance between the DC bus bars 6p and 6n can be narrowed as compared with the conventional case where a gap is simply provided between the pair of DC bus bars, and the parasitic inductance of the DC bus bar 6 can be reduced. it can. For this reason, it is possible to suppress the occurrence of a large surge during the switching operation of the semiconductor element 20 due to this inductance.

As shown in FIG. 5, the DC bus bar 6 of this example includes a plate-like bus bar main body 61 and a terminal 62 connected to the bus bar main body 61 and connected to the semiconductor module 2. As shown in FIG. 7, the bus bar main body 61 and the reinforcing rib 53 are arranged so that their thickness directions coincide with each other. And the bus-bar main-body part 61, the insulating layer 7, and the reinforcement rib 53 are laminated | stacked on the said thickness direction (Y direction).
Therefore, the area where DC bus bars 6p and 6n overlap can be increased. Therefore, inductance can be reduced more effectively.

  The insulating layer 7 in this example is made of an insulating resin. Insulating resin is inexpensive and has excellent durability. Further, at the time of manufacturing, it is only necessary to bond the insulating layer 7 formed in advance to the reinforcing rib 53, so that it can be manufactured easily.

  In this example, the reinforcing rib 53 is formed integrally with the case 5. The reinforcing rib 53 can be configured as a separate member from the case 5, but in this case, there is a problem that the number of parts increases. Moreover, since it becomes necessary to fix the reinforcement rib 53 to the to-be-pressurized wall parts 51 and 52 using a volt | bolt etc., the manufacturing man-hour of the power converter device 1 will increase. On the other hand, if the reinforcing rib 53 is integrated with the case 5 as in this example, an increase in the number of parts and the number of manufacturing steps can be suppressed. Therefore, the manufacturing cost of the power converter device 1 can be reduced.

  In this example, as shown in FIG. 3, the electrode plates 113 and 114 of the capacitor 11 and the DC bus bar 6 are integrated. Therefore, the number of parts can be reduced, and the manufacturing cost of the power conversion device 1 can be further reduced.

  Further, as shown in FIG. 8, the case 5 of this example includes a plurality of reinforcing plates 54 in addition to the reinforcing ribs 53. Therefore, the rigidity of the case 5 can be further increased. Therefore, the problem that the case 5 is deformed by the pressure F of the pressing member 4 can be more effectively suppressed.

  In this example, the structure 10 is formed by laminating a plurality of semiconductor modules 2 and the cooling pipe 30. In this case, since the length of the structure 10 in the X direction tends to be long, the structure 10 is likely to swing in a direction orthogonal to the X direction when vibration is applied. Therefore, it is necessary to strongly press the structure 10 using the pressing member 4 having a high spring constant, and to firmly hold the structure 10 in the case 5. Accordingly, the strong pressure F of the pressure member 4 is easily applied to the case 5. Therefore, the effect obtained by providing the reinforcing rib 53 and increasing the rigidity of the case 5 is great.

  Moreover, the power converter device 1 of this example is mounted on a vehicle. Therefore, large vibrations are likely to occur as the vehicle travels. Therefore, as in this example, the effect obtained by providing the reinforcing ribs 53 and the insulating layer 7 between the pair of DC bus bars 6 so that the DC bus bars 6 do not come into contact with each other even when vibration is applied is great.

  As described above, according to this example, it is possible to provide a power conversion device that can increase the rigidity of the case and reduce inductance parasitic on the DC bus bar.

  In this example, an insulating resin is used as the insulating layer 7. However, the present invention is not limited to this, and insulating paper can also be used. Since the insulating paper is inexpensive, the manufacturing cost of the power conversion device 1 can be reduced.

(Example 2)
In the following examples, the same reference numerals used in the drawings among the reference numerals used in the drawings represent the same components as in the first embodiment unless otherwise specified.

  In this example, the material constituting the insulating layer 7 is changed. The insulating layer 7 in this example is made of an insulating paint. As shown in FIG. 10, the insulating layer 7 is applied directly to the reinforcing rib 53, and no adhesive layer 71 (see FIG. 7) is interposed between the insulating layer 7 and the reinforcing rib 53. The insulating layer 7 covers the entire reinforcing rib 53.

The effect of this example will be described. When an insulating paint is used as the insulating layer 7, the insulating layer 7 can be directly applied to the reinforcing rib 53, so that it is not necessary to provide the adhesive layer 71 between the insulating layer 7 and the reinforcing rib 53. Therefore, the DC bus bar 6 can be brought closer by the reinforcing rib 53. Therefore, the interval between the pair of DC bus bars 6 (6p, 6n) can be narrowed, and the inductance parasitic on the DC bus bar 6 can be further reduced.
In addition, the configuration and operational effects are the same as those of the first embodiment.

  In place of the insulating paint, a thermosetting resin may be directly applied to the reinforcing rib 53 and heated to be cured. Also in this case, since the adhesive layer 71 is not necessary, the interval between the pair of DC bus bars 6 (6p, 6n) can be made narrower. Therefore, the inductance parasitic on the DC bus bar 6 can be reduced.

(Example 3)
In this example, the shape of the DC bus bar 6 is changed. As shown in FIGS. 11 and 12, the DC bus bar 6 of this example includes a plate-like bus bar main body 61 and a U-shaped portion 63 connected to the bus bar main body 61. The bus bar main body 61 is arranged so that the thickness direction thereof coincides with the protruding direction (Z direction) of the power terminal 22. In this example, the bus bar main body 61 and the power terminal 22 are welded by bringing the bus bar main body 61 into contact with the distal end surface 220 of the power terminal 22 and irradiating a laser beam, an electron beam, or the like. A welding mark 610 remains on the bus bar main body 61.
In addition, the configuration and operational effects similar to those of the first embodiment are provided.

DESCRIPTION OF SYMBOLS 1 Power converter 10 Structure 2 Semiconductor module 20 Semiconductor element 3 Cooler 4 Pressure member 5 Case 51, 52 Wall to be pressurized 53 Reinforcement rib 6 DC bus bar 7 Insulating layer 8 DC power supply F Pressurizing force

Claims (6)

A structure (10) comprising a semiconductor module (2) containing a semiconductor element (20) and a cooler (3) for cooling the semiconductor module (2);
A pair of direct current bus bars (6) connected to the semiconductor module (2), forming a direct current path between the direct current power source (8) and the semiconductor element (20), and facing each other;
A case (5) for housing the structure (10) and the pair of DC bus bars (6);
The structure (10) is housed in the case (5), and the structure (10) is pressurized to fix the structure (10) in the case (5), and the semiconductor module (2) and the cooler ( 3) and a pressure member (4) for tightly adhering
The structure (10), the pressure member (4), and the pair of DC bus bars (6) include a pair of pressurized wall portions (51) facing each other among the wall portions constituting the case (5). , 52), and the pressure (F) of the pressure member (4) is applied to the pair of walls to be pressurized (51, 52),
In the case (5), a reinforcing rib (53) that connects the pair of pressurized walls (51, 52) is formed,
The reinforcing rib (53) is provided between the pair of DC bus bars (6), and an insulating layer (7) is provided between the DC bus bar (6) and the reinforcing rib (53) to insulate them. The power converter device (1) characterized by interposing.   The DC bus bar (6) includes a plate-like bus bar main body (61) and a terminal portion (62) connected to the bus bar main body (61) and connected to the semiconductor module (2), and the reinforcing ribs. (53) is formed in a plate shape, and the bus bar main body (61) and the reinforcing rib (53) are arranged so that their thickness directions coincide with each other, and the bus bar main body (61) The power converter (1) according to claim 1, wherein the insulating layer (7) and the reinforcing rib (53) are laminated in the thickness direction.   The power converter (1) according to claim 1 or 2, wherein the reinforcing rib (53) is formed integrally with the case (5).   The power conversion device (1) according to any one of claims 1 to 3, wherein the insulating layer (7) is made of insulating paper.   The power conversion device (1) according to any one of claims 1 to 3, wherein the insulating layer (7) is made of an insulating paint.   The said insulating layer (7) consists of insulating resin, The power converter device (1) of any one of Claims 1-3 characterized by the above-mentioned.

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