JP2019103247A - Cooling structure for power converter - Google Patents

Abstract

To provide a technology for reducing a height by avoiding a stacked structure of a plurality of bus bars and improving heat extraction efficiency with respect to a volume of the plurality of bus bars as a whole.SOLUTION: The cooling structure for a power converter mounted with a power module mounted with switching elements corresponding to multiple phases of power, includes: a water channel formation unit which forms a cooling water channel on a surface on a back side of a surface on which the switching element is mounted in the power module; a plurality of bus bars connected to each phase of the power module and heat conductively connected to the water channel formation unit; and a housing accommodating at least a part of each of the bus bars between the water channel formation portion and the housing.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cooling structure for a power converter.

  Conventionally, in a vehicle-mounted inverter, bus bars of U-phase, V-phase, and W-phase are stacked via an insulating material, and the stacked bus bars are pressed against a housing using a bracket and a bolt to heat the bus bars. There is known a technique for radiating heat to the casing (see Patent Document 1).

Unexamined-Japanese-Patent No. 2006-271063

  However, in the technique disclosed in Patent Document 1, since the plurality of bus bars have a stacked structure, the mounting space of the inverter including the stacked bus bars becomes large. Further, in the bus bar of the laminated structure, the heat removal efficiency is lowered as the bus bar is at a position farther from the housing, so there is a problem that the heat removal efficiency with respect to the volume of the plurality of bus bars is lowered.

  An object of the present invention is to provide a technology for reducing the height by avoiding a stacked structure of a plurality of bus bars and improving the heat extraction efficiency with respect to the volume of the plurality of bus bars as a whole.

  According to the cooling structure for a power converter according to the present invention, in a cooling structure for a power converter on which a power module mounted with switching elements corresponding to plural phases of power is mounted, the back side of the surface on which the switching elements in the power module are mounted It has a channel formation part which forms a cooling channel on the surface, and a plurality of bus bars which are connected to each phase of the power module and are connected to the channel formation part in a heat conductive manner, and further between the channel formation part And a housing that accommodates part of the bus bar.

  According to the present invention, since the space on the back side of the power module can be effectively used to arrange the plurality of bus bars in the plane direction, the height can be reduced while avoiding the stacked structure of the plurality of bus bars. The heat removal efficiency with respect to the volume of the plurality of bus bars can be improved.

FIG. 1 is a schematic circuit diagram showing the power converter of the first embodiment. FIG. 2 is a diagram for explaining the cooling structure of the power module. FIG. 3 is a schematic configuration view of the power module as viewed from the back. FIG. 4 is a schematic configuration view showing the power module in a state in which the bus bar is disposed. FIG. 5 is a diagram for explaining the effect of the power converter cooling structure of the first embodiment. FIG. 6 is a schematic configuration view showing a power module in which bus bars are arranged in the first modification. FIG. 7 is a schematic configuration view showing a power module in which bus bars are arranged in the second modification. FIG. 8 is a diagram showing an aspect in which the bus bar and the water channel formation portion are in contact in the third modification. FIG. 9 is a diagram for explaining an aspect in which the output terminal of the power module and the bus bar are connected in the fourth modification. FIG. 10 is a view for explaining the cooling structure of the power module of the fifth modification. FIG. 11 is a diagram for explaining the bus bar of the second embodiment.

  A power converter cooling structure according to an embodiment of the present invention will be described.

-1st Embodiment-
First, the power converter 1 will be described. FIG. 1 is a schematic circuit diagram showing a configuration of a power converter 1 according to an embodiment of the present invention. The power converter 1 according to the present embodiment is, for example, a vehicle-mounted inverter.

  Power converter 1 is provided between DC power supply 2 and electric motor (rotary electric machine) 3.

  The DC power source 2 is a power source of a vehicle or the like, and is configured of a plurality of batteries and the like. DC power supply 2 has a positive electrode connected to positive electrode feed bus 10P in power converter 1 through positive electrode wire 4P, and a negative electrode with negative electrode feed bus 10N in power converter 1 via negative electrode wire 4N. It is connected.

  The motor 3 of the present embodiment operates in a plurality of phases (three phases of the U phase, the V phase, and the W phase in the present embodiment). The electric motor 3 is rotationally driven by being supplied with an alternating current generated by the power converter 1 converting a direct current from the direct current power supply 2. Power converter 1 and motor 3 are connected via U-phase bus bar 5U, V-phase bus bar 5V, and W-phase bus bar 5W.

  The power converter 1 includes a power module 13 configured to include a substrate on which a plurality of modularized semiconductor elements 11A, 11B, 11C, 12A, 12B, and 12C are mounted. The semiconductor elements 11A, 11B, 11C, 12A, 12B, and 12C are semiconductor elements (switching elements) capable of high-speed, high-speed switching, and are, for example, IGBTs (Insulated Gate Bipolar Transistors). The semiconductor elements 11A, 11B, 11C, 12A, 12B, and 12C convert DC power into AC power by turning ON / OFF (opening and closing) in accordance with a signal from the control circuit 17. Then, when alternating current power for obtaining a desired rotational force is generated by the motor 3, the generated alternating current is output to the motor 3 via the bus bars 5U, 5V, 5W corresponding to each phase described above. .

  The bus bars 5U, 5V, 5W are plate-like conductors, and are electrically connected to the corresponding output terminals (strong electric terminals) 13a, 13b, 13c of the power module 13, and are of each phase generated by the power module 13. AC power is supplied to the motor 3. The bus bars 5U, 5V and 5W shown in FIG. 1 are drawn so as to connect in a straight line from the connection portion with the output terminals 13a, 13b and 13c to the current input I / F (three phase I / F) of the motor 3. But in practice it is not limited to this. The details of the configuration (drawing) of the bus bars 5U, 5V, 5W, which is a feature of the present embodiment, will be described later.

  Further, in FIG. 1, although the output terminals 13a, 13b, 13c to the input I / F of the motor 3 are connected by only the bus bars 5U, 5V, 5W, the present invention is not limited thereto. For example, the bus bars 5U, 5V, 5W May be connected to the input I / F of the motor 3 via power supply wiring (not shown) corresponding to each phase. Further, as long as the switching elements of each phase in the power module 13 and the output terminals 13a, 13b and 13c are electrically connected, the aspect is not particularly limited. For example, plate-shaped conductors similar to the bus bars 5U, 5V, 5W may be used. In the following, when the bus bars 5U, 5V, and 5W are not particularly distinguished, they are simply referred to as the bus bars 5.

  The power converter 1 further includes a smoothing capacitor 14 that absorbs fluctuations in the input voltage to the semiconductor element between the positive electrode feed bus 10P and the negative electrode feed bus 10N. The smoothing capacitor 14 is connected to a feed bus connecting the DC power supply 2 and the power converter 1 to suppress a part of voltage fluctuation due to switching.

  The electric motor 3 is, for example, an alternating current power motor used for an electric car or the like, and serves as a traveling drive source of the vehicle. In such a case, the output shaft of the motor 3 is connected to the axle of the electric vehicle. In the present embodiment, the power converter 1 for driving the motor 3 is not limited to an electric vehicle, but can be applied to a hybrid vehicle (HEV), and can also be applied to devices other than a vehicle.

  Since the on-vehicle power converter 1 as described above is configured to control high power, the input / output current of the mounted power module 13 is large. Therefore, the amount of heat generation of the bus bar 5 connected to the power module 13 and to which the alternating current output from the power module 13 flows is also increased. When the temperature of the bus bar 5 rises, the temperature rise of the semiconductor element of the power module 13 becomes large, so that not only the element fails but also the temperature inside the power converter 1 and the substrate on which the element is mounted Problems may occur such as failure of other mounted components in the power converter 1 as well. Therefore, in the power converter 1 that controls high power, particularly, by cooling the bus bar 5, the switching element connected to the bus bar 5 and the power module 13 accommodating the bus bar 5 and the heat in the power converter 1 are efficiently used. It is important to dissipate the heat well (heat removal).

  Hereinafter, a cooling structure for a power converter according to an embodiment of the present invention will be described.

  FIG. 2: is a schematic block diagram explaining the cooling structure of the power module 13 which the power converter 1 which concerns on this embodiment mounts. The specific configuration in the power module 13 is as described above with reference to FIG. In the power module 13 of the present embodiment, a substrate on which a plurality of switching elements 11A, 11B, 11C, 12A, 12B, 12C corresponding to U, V, W phases are mounted (for example, as shown in FIG. (Refer to the dotted frame of).

  In the power module 13, the outer surface 1a on the side on which the substrate on which the switching element corresponding to the U, V, and W phases is mounted is mounted, in other words, the surface on the back side of the mounting surface of the semiconductor element in the power module 13. A cooling channel 8 is formed in 1a. More specifically, a cooling water channel 8 is formed by the back surface 1 a and the water channel forming portion 7 on the back surface 1 a of the power converter 1 (hereinafter simply referred to as “back surface 1 a”).

  The water channel formation portion 7 of the present embodiment is formed continuously with the back surface 1 a of the power module 13. That is, the power module 13 and the water channel formation portion 7 are integrally configured. In other words, the power module 13 of the present embodiment has the cooling water passage 8 constituted by the back surface 1 a and the water passage forming portion 7 extending from the back surface 1 a.

  The cooling water channel 8 (hereinafter simply referred to as “water channel 8”) is configured such that the cooling water flows in the water channel 8 and cools the power module 13 and the bus bar 5. More specifically, the water passage 8 promotes heat radiation from the back surface 1 a of the power module 13 by the cooling water flowing in the water passage 8 and of the bus bar 5 connected to the cooling water and the water passage forming portion 7 so as to be thermally conductive. Promote heat dissipation. Further, by cooling the bus bar 5 between the power module 13 and the housing 9, the motor 3 which is the connection destination of the bus bar 5 on the opposite side to the power module 13, and the electronic component provided in the motor 3 such as a reactor. It is possible to suppress heat reception from As illustrated, the water channel 8 may be provided with a plurality of pins (fins) 6 formed to project from the back surface 1 a. The pin 6 increases the contact area between the power module 13 and the cooling water flowing in the water passage 8 and further promotes the heat exchange between the power module 13 and the cooling water, whereby the cooling efficiency (heat removal efficiency) of the water passage 8 is achieved. Improve.

  The bus bars 5U, 5V, 5W are drawn from the connection position of the output terminals 13a, 13b, 13c (not shown) of the power module 13 through the side of the power module 13 to the back (rear) side, And heat conductively connected (contact). Further, as illustrated, the bus bars 5U, 5V, and 5W are configured such that the surfaces (surfaces in the width direction) on the side where the respective areas are wider contact the water channel formation portion 7. The width direction in the present specification is the direction of the double arrow shown in FIG. Furthermore, the bus bars 5U, 5V, 5W are arranged in the surface direction without overlapping at the contact surface with the water channel formation portion 7. Details of the routing of the bus bar 5 will be described later.

  Then, the housing 9 accommodates at least a part of the bus bar 5 between the water channel forming portion 7 and the housing 9. The housing 9 is a housing that constitutes the power converter 1. When mounted on the vehicle, the housing 9 is mounted on a vehicle integrally with the power module 13 and the cooling water in the water channel 8 is mainly converted from the power module 13 to the power conversion. Prevent water leakage to the outside of vessel 1.

  The details of the configuration of the bus bar 5 will be described below.

  FIG. 3 is a schematic configuration view of the power module 13 of the present embodiment as viewed from the back surface (from the side of the casing 9 in FIG. 2). As illustrated, on the back surface 1 a of the power module 13, the water channel 8 configured by the water channel forming portion 7 is provided. And in this embodiment, it is a part of back 1a of power module 13, and bus bar 5 is arranged so that it may contact channel formation part 7 which constitutes channel 8.

  FIG. 4 is a schematic configuration view showing the power module 13 in a state in which the bus bar 5 is disposed in the present embodiment. 4 (a) shows the power module 13 viewed from the front, FIG. 4 (b) shows the power module 13 viewed from the side, and FIG. 4 (c) shows the back of the power module 13. Shows a view from the rear (rear view). Further, in the bus bar 5, a portion where the dots are denser (portion having a dark color) represents a portion (cooled area) in direct or indirect contact with the water channel forming portion 7. In addition, "indirectly" here shows that the bus-bar 5 and the water channel formation part 7 contact via the insulating material 15 mentioned later, for example. Although the housing 9 is not shown in FIG. 4C, the bus bar 5 shown in FIG. 4C is actually between the back surface 1a (water channel forming portion 7) of the power module 13 and the housing 9 Is located in In other words, the housing 9 accommodates at least a part of the bus bar 5 between it and the water passage forming portion 7.

  As illustrated, the bus bar 5 is connected to the output terminals 13a, 13b and 13c at the front of the power module 13 (see FIG. 4A) and passes through the side of the power module 13 (see FIG. 4B). ), Is routed around the back surface 1 a of the power module 13. The output terminals 13a, 13b, 13c and the bus bar 5 of the present embodiment may be fastened by bolting or the like.

  And as shown in FIG.4 (c), the bus-bar 5 covers the back surface 1a of the power module 13, and secures a contact area (area to be cooled) with the water channel formation part 7, The input I of the electric motor 3 It is pulled out in the direction (the arrow direction in the figure) of / F (3 phase I / F). That is, in the bus bar 5 of the present embodiment, the drawing direction from the connection position with the output terminals 13a, 13b, 13c of the power module 13 is changed at the back surface 1a of the power module 13 to the input I / F of the motor 3. It is drawn around.

  FIG. 5 is a view for explaining the effect of the cooling structure for the power converter 1 of the present embodiment. FIG. 5A shows a schematic configuration when the bus bars 5U, 5V and 5W of the present embodiment are in contact with the water channel formation portion 7 on the back surface 1a of the power module 13 as viewed from the side of the power module. FIG. 5 (B) is a schematic configuration view showing a cooling structure of a bus bar in a conventional power converter (see Patent Document 1).

  The bus bar 5 shown in FIG. 5A is in contact with the water passage forming portion 7 via the insulating material 15. Further, the bus bars 5U, 5V, 5W are mutually insulated by the insulating material 15. As shown in the figure, in the present embodiment, since the area to be cooled of the bus bar 5 can be secured by effectively utilizing the area of the back surface 1 a of the power module 13, the bus bar 5 can be secured. The bus bars 5 can be arranged side by side in the surface direction of the back surface 1 a without overlapping each of the above. In FIG. 5, the bus bar 5 is in contact with the water passage forming portion 7 through the insulating material 15. However, when the material forming the water passage forming portion 7 is an insulating material, the bus bar 5 is in direct contact with the water passage forming portion 7. You may Note that as the insulating material here, a general resin having an insulating property, ceramic, or the like may be used.

  In addition, it is preferable that the insulating material 15 has elasticity. Thus, the insulating material 15 can also serve as a tolerance absorbing function in addition to the insulating function, so the contact area between the bus bar 5 and the water channel forming portion 7 can be secured more reliably.

  As described above, in the cooling structure for the power converter 1 of the present embodiment, the bus bars 5U, 5V, 5W can be brought into contact with the water channel forming portion 7 directly or only through the insulating material 15, respectively. It is possible to suppress an increase in the thermal resistance from the water passage 8 to the water passage 8 and to improve the heat removal efficiency with respect to the volume of the entire bus bar 5. In addition, since it is not necessary to stack bus bars 5U, 5V, 5W as in the prior art, and the height of power module 13 can be reduced, for example, the mounting space of power converter 1 can be reduced at the time of vehicle mounting. Can.

  On the other hand, in the conventional cooling structure, as shown in FIG. 5 (B), it is necessary to make the bus bar corresponding to each phase into a laminated structure. Moreover, when making a bus-bar into a laminated structure, the insulating material 15 for mutually insulating a bus-bar becomes an essential component. Then, the uppermost bus bar of the laminated structure, in other words, the bus bar located farthest from the cooling water channel, insulates at least another plurality of bus bars and them from one another to the housing having the cooling water channel. And at least three layers of the insulating material including the insulating material. As a result, in the bus bar of the laminated structure, the thermal resistance from the bus bar to the cooling water passage increases in the upper stage, so the required cooling area of the bus bar increases in proportion to the increase in the thermal resistance. is there.

  In the cooling structure for the power converter 1 of the present embodiment, the conventional problems can be solved by the above-described configuration, and the thermal resistance from the bus bars 5U, 5V, 5W to the water channel 8 can be significantly reduced compared to the conventional one.

  In the following, differences between the first to fifth modifications of the cooling structure for the power converter 1 of the present embodiment will be mainly described.

<Modification 1>
FIG. 6 is a schematic configuration view showing the power module 13 in a state in which the bus bar 5 is arranged in the first modification. 6 (a) shows the power module 13 viewed from the front, FIG. 6 (b) shows the power module 13 viewed from the side, and FIG. 6 (c) shows the back of the power module 13. Shows a view from the rear (rear view). 6 (a) and 6 (b) are the same as the configuration of the first embodiment described with reference to FIGS. 4 (a) and 4 (b).

  In the first modification, as shown in FIG. 6C, the bus bars 5V and 5W are drawn in a straight line on the back surface of the power module 13. Thus, the routing of the bus bar 5 on the back surface of the power module 13 is not limited to the configuration shown in FIG.

<Modification 2>
FIG. 7 is a schematic configuration view showing the power module 13 in a state in which the bus bar 5 is arranged in the second modification. 7 (a) shows a front view of the power module 13, FIG. 7 (b) shows a side view of the power module 13, and FIG. 7 (c) shows the back of the power module 13. Shows a view from the rear (rear view). FIGS. 7A and 7B are the same as the configurations of the first embodiment and the first modification described above with reference to FIGS. 4A and 4B.

  In the second modification, as shown in FIG. 7C, the width in the lateral direction of the bus bars 5V and 5W in the surface direction is smaller (thin) than in the first embodiment and the first modification. That is, in the second modification, the bus bar width is changed according to the length (cooling length) of the bus bar 5 in contact with the water passage forming portion 7. The reason why the bus bar width can be changed in this way is that, for example, assuming that the cooled area of the bus bar 5W is necessary and sufficient, the bus bars 5U, 5V will have the bus bar 5W even if the cooling length is narrower than the bus bar 5W. This is because the same area to be cooled can be secured. Further, not only the width but also the thickness of the bus bar 5 may be variable. For example, the thickness of the bus bars 5U and 5V may be reduced so that the heat removal efficiency in the area to be cooled is equal to that of the bus bar 5W. That is, the cross-sectional area of the bus bar 5 according to the second modification may be appropriately set in accordance with the area (the area to be cooled) in which each of the bus bars 5 contacts the water channel formation portion 7. Here, the “cross-sectional area” is an area of a cross section perpendicular to the current flow direction in the bus bar 5.

  As described above, in the second modification, at least one of the width or the thickness of the bus bar 5 can be made variable on the premise that a necessary and sufficient area to be cooled is secured from the viewpoint of heat exchange with the cooling water. As a result, on the back surface of the power module 13, the bus bar 5 can be configured to have an appropriate size (size) without excess or deficiency.

<Modification 3>
FIG. 8 is a diagram showing an aspect in which the bus bar 5 and the water channel formation portion 7 are in contact in the third modification. As illustrated, the water channel forming portion 7 of the third modification has a convex portion 7 a provided at a position where the bus bar 5 is routed. Thereby, by pressing the bus bar 5 against the water channel forming portion 7 by bolting or the like, the bus bar 5 through the convex portion 7 a does not require, for example, the insulating material 15 (tolerance absorbent) having a tolerance absorbing function described above. Can be reliably brought into contact with the water channel formation portion 7. The shape of the portion of the convex portion 7a in contact with the bus bar 5 in particular is not limited to the shape illustrated, but may be appropriately set from the viewpoint of securing the area to be cooled.

<Modification 4>
FIG. 9 is a view for explaining an aspect in which the output terminals 13a, 13b and 13c of the power module 13 and the bus bar 5 are connected in the fourth modification. FIG. 9 shows a connection mode of the output terminal 13b and the bus bar 5V as a representative of these. The bus bar 5 of the fourth modification is connected to the output terminals 13 a, 13 b and 13 c of the power module 13 by welding. Thereby, since the output terminals 13a, 13b, 13c and the bus bar 5 are connected with continuity, the thermal resistance at the connection portion is reduced as compared to connection by surface contact such as bolting or the like. be able to. As a further modification, the output terminals 13a, 13b, 13c and the bus bar 5 may be connected by press fitting. Even in the case of the press-fit connection, the thermal resistance of the connection portion can be reduced as compared to the case of fastening by surface contact such as bolting.

<Modification 5>
FIG. 10 is a schematic configuration view illustrating a cooling structure of the power module 13 according to the fifth modification. In the fifth modification, in particular, the configuration of the water channel formation portion 7 is different from that of the first embodiment described above.

  Water channel formation part 7 of modification 5 is formed continuously with case 9. In other words, the housing 9 and the water channel formation portion 7 are integrally configured. That is, the water channel 8 of this example is configured by the back surface 1 a of the power module 13 and the housing 9.

  Then, the bus bar 5 of the present example is configured to be connected (contacted) in a thermally conductive manner with the surface 9 a on the water channel 8 side in the space 16 in the housing 9. More specifically, the bus bar 5 is guided from the connection position of the output terminals 13a, 13b, 13c (not shown) of the power module 13 through the side surface of the power module 13 into the housing 9 and the surface 9a (water channel It is routed around the forming portion 7) to secure a contact area (area to be cooled) with the water channel forming portion 7. The direction of routing and the like may be the same as in the first embodiment, and are appropriately set.

  Also, in the case where the material of the bus bar 5 according to the present embodiment which constitutes at least the water passage forming portion 7 of the housing 9 is an insulating material, the bus bar 5 is disposed embedded in the water passage forming portion 7 or the like. Thus, the insulating material 15 can be made unnecessary.

  In the space 16, electronic components other than the bus bar 5 may be disposed. In particular, when the electronic component or the like generates heat, the electronic component or the substrate on which the electronic component is mounted is disposed on the surface 9 a side in the space 16 to dissipate heat of the electronic component by heat exchange with the water channel 8 ( Heat removal) can be promoted.

  In addition, since the housing | casing 9 which concerns on this example forms a water channel between the back surfaces 1a of the power module 13, it is also called a so-called water jacket as a housing | casing for water leak prevention.

  As described above, according to the cooling structure for the power converter 1 of the first embodiment (including the first to fifth modifications), the switching elements 11A, 11B, 11C, 12A, 12B, and 12C corresponding to the power of a plurality of phases are mounted. In the cooling structure for the power converter 1 on which the power module 13 is mounted, a water channel that forms the cooling water channel 8 on the back surface of the surface on which the switching elements 11A, 11B, 11C, 12A, 12B, 12C in the power module 13 are mounted A formation portion 7 and a plurality of bus bars 5 connected to the respective phases of the power module 13 and connected to the water flow path formation portion 7 in a heat conductive manner, and further, the bus bar 5 between the water flow path formation portion 7 and And a housing 9 for housing a part of the housing. As a result, the space on the back side of the power module 13 can be effectively utilized, and the plurality of bus bars 5 can be arranged side by side in the plane direction, so that the stacked structure of the plurality of bus bars 5 can be avoided to reduce the height. The heat removal efficiency with respect to the volume of the plurality of bus bars 5 can be improved.

  Further, according to the cooling structure for the power converter 1 of the first embodiment, the water channel formation portion 7 is formed continuously with the power module 13 or the housing 9. Thereby, the cooling structure for power converters 1 provided with the cooling channel 8 united with power module 13 or case 9 can be provided.

  Further, according to the power converter cooling structure of the first embodiment, the cross-sectional area of the bus bar 5 is set in accordance with the size of the area in contact with the water passage forming portion 7. As a result, on the back surface of the power module 13, the bus bar 5 can be configured to have an appropriate size (size) without excess or deficiency.

  Moreover, according to the cooling structure for the power converter 1 of the first embodiment, the water channel formation portion 7 is formed of an insulating material. Thereby, the insulating material 15 for insulating the bus bar 5 and the water channel forming portion 7 which was necessary when the water channel forming portion 7 is formed of a conductive material such as aluminum, and the bus bar 5 U , 5 V, and 5 W can be dispensed with.

  Moreover, according to the cooling structure for the power converter 1 of the first embodiment, the bus bar 5 is thermally conductively connected to the water passage forming member via the insulating material 15 having elasticity. Thus, the insulating material 15 can also serve as a tolerance absorbing function in addition to the insulating function, so the contact area between the bus bar 5 and the water channel forming portion 7 can be secured more reliably.

  Moreover, according to the cooling structure for the power converter 1 of the first embodiment, the portion of the water passage forming portion 7 in contact with the bus bar 5 is formed in a convex shape. As a result, for example, the bus bar 5 and the water channel forming portion 7 can be reliably contacted via the convex portion 7a without requiring a tolerance absorbent such as the insulating material 15 having the tolerance absorption function described above.

  Moreover, according to the cooling structure for the power converter 1 of the first embodiment, the high voltage terminals 13a, 13b, 13c of the power module 13 and the bus bar 5 are connected by welding or press fitting. Thereby, the thermal resistance of the connection portion (connection surface) can be reduced as compared with the fastening of the output terminals 13a, 13b, 13c and the bus bar 5 by surface contact such as bolting. As a result, the heat of the power module 13 to the power converter 1 can be dissipated more efficiently.

-Second embodiment-
Hereinafter, a power converter cooling structure according to a second embodiment of the present invention will be described. In the second embodiment, the configuration of the bus bar 5 is different from that of the first embodiment.

  FIG. 11 is a diagram for explaining the bus bar 5 of the second embodiment. In FIG. 11, only the bus bar 5U is illustrated among the bus bars 5U, 5V, and 5W.

  The bus bar 5 (5U, 5V, 5W) of the present embodiment is characterized in that it includes the cooling bus bar 25 (25U, 25V, 25W) branched at a predetermined distance from the connection position with the output terminal 13a of the power module 13. There is. That is, the bus bar 5 of the present embodiment is configured to include the bus bar 5 (high power conduction bus bar) which is output from the power module 13 and to which the strong power supplied to the motor 8 is energized and the cooling bus bar 25. Then, the cooling bus bar 25 branched from the bus bar 5 passes around the side surface of the power module 13 so as to cover the back surface 1 a (water channel forming portion 7) of the power module 13 as shown in the figure. The contact area (area to be cooled) with the formation portion 7 is secured. That is, in the second embodiment, at least a part of the cooling bus bar 25 is accommodated between the water passage forming portion 7 and the housing 9, and the heat of the bus bar 5 is dissipated to the water passage 8 via the cooling bus bar 25. Ru.

  The predetermined distance from the connection position with the power module 13 to the position where the cooling bus bar 25 branches may be appropriately set from the viewpoint of thermal conductivity or the reduction of the mounting space. For example, from the viewpoint of thermal conductivity, the branch point of the cooling bus bar 25 is set to a position that can reach the back surface 1 a of the power module 13 with the shortest distance when viewed from the connection position with the power module 13. Is preferred.

  The cooling bus bar 25 does not necessarily have to be branched from the high power conduction bus bar 5 and may be configured as a separate member having at least thermal conductivity and be connected to the high power conduction bus bar 5 so as to be thermally conductive. .

  As described above, according to the cooling structure for the power converter 1 of the second embodiment, the bus bar 5 is branched into the high power bus bar 5 and the cooling bus bar 25 at a predetermined distance from the connection position with the power module 13. The cooling bus bar 25 is accommodated between the water channel forming portion 7 and the housing 9. With such a configuration as well, the space on the back side of the power module 13 can be effectively utilized, and the plurality of bus bars 5 can be arranged side by side in the plane direction, so a stacked structure of the plurality of bus bars 5 can be avoided to reduce height. It is possible to improve the heat removal efficiency with respect to the volume of the plurality of bus bars 5 overall. Further, the degree of freedom of the routing of the bus bar 5 can be further improved as compared with the first embodiment.

  Further, according to the cooling structure for the power converter 1 of the second embodiment, the cooling bus bar 25 is a separate member from the high voltage bus bar 5 and the cooling bus bar 25 is formed of a member having heat conductivity. The bus bar 5 for high electric current conduction is connected to the water passage forming portion 7 via the cooling bus bar 25 so as to be capable of heat conduction. Thereby, as compared with the first embodiment, the degree of freedom of the routing of the bus bar 5 can be further improved.

  As mentioned above, although embodiment of this invention and its modification were described, the said embodiment and modification only showed a part of application example of this invention, and the technical scope of this invention is said embodiment and said It is not the meaning limited to the concrete composition of a modification. Moreover, the said embodiment and its modification are combinable suitably in the range which a contradiction does not produce.

  For example, the configuration relating to the drawing of the bus bar 5 of the aspect described in the first embodiment, the first modification, and the second modification is applied to the configuration relating to the drawing of the bus bar 5 in the space 16 in the housing 9 according to the fifth modification. It is possible.

  In FIGS. 2, 10 and 11, the upper side of the power module 13 (the opposite side of the water passage 8) is shown in an exposed state, but actually the upper side of the power module 13 is also accommodated in the housing 9. May be configured (covered).

1 ... power converter 5 ... bus bar (bus bar, bus bar for high power energization)
7 ... water channel formation part 8 ... water channel (cooling water channel)
9: Casing 11A, 11B, 11C, 12A, 12B, 12C ... Switching element 13 ... Power module 13a, 13b, 13c ... Output terminal (strong power terminal)
15: Insulating material 25: Bus bar (bus bar, cooling bus bar)

Claims (9)

In a cooling structure for a power converter mounted with a power module mounted with switching elements corresponding to multiple phases of power,
A water channel formation portion which forms a cooling water channel on the surface on the back side of the surface on which the switching element is mounted in the power module;
A plurality of bus bars connected to the respective phases of the power module and thermally conductively connected to the water channel forming portion;
A housing that accommodates at least a portion of each of the bus bars between the channel forming portion and the housing;
Cooling structure for a power converter characterized by The water channel formation portion is formed continuously with the power module or the housing.
A cooling structure for a power converter according to claim 1, characterized in that. The cross-sectional area perpendicular to the current flow direction of the bus bar is set according to the size of the area in contact with the water channel formation portion.
The cooling structure for a power converter according to claim 1 or 2, characterized in that: The water channel formation portion is formed of an insulating material.
The cooling structure for a power converter according to any one of claims 1 to 3, characterized in that. The bus bar is thermally conductively connected to the water channel formation portion via an elastic insulating material.
The cooling structure for a power converter according to any one of claims 1 to 4, characterized in that. In the water channel formation portion, a portion in contact with the bus bar is formed in a convex shape.
The cooling structure for a power converter according to any one of claims 1 to 4, characterized in that. The high voltage terminal of the power module and the bus bar are connected by welding or press fitting.
The cooling structure for a power converter according to any one of claims 1 to 6, characterized in that. The bus bar branches into a high power bus bar and a cooling bus bar at a predetermined distance from the connection position with the power module.
At least a portion of the cooling bus bar is accommodated between the water channel forming portion and the housing.
The cooling structure for a power converter according to any one of claims 1 to 7, characterized in that: The cooling bus bar is a separate member from the high power bus bar, and
The cooling bus bar is composed of a member having heat conductivity, and the high-power bus bar is connected to the water passage forming portion so as to be thermally conductive via the cooling bus bar.
The cooling structure for a power converter according to claim 8, characterized in that.

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