JP7396020B2 - power converter - Google Patents

Description

The technology disclosed in this specification relates to a power converter including a stacked unit in which a plurality of semiconductor modules and a plurality of coolers are stacked.

A power converter is known that includes a stacked unit in which a plurality of semiconductor modules and a plurality of coolers are stacked. In the power converter disclosed in Patent Document 1, the stacked unit is biased along the stacking direction by an elastic member. The stacking direction means the stacking direction of a plurality of semiconductor modules and a plurality of coolers.

The laminated unit and the elastic member are sandwiched between two stoppers (a first stopper and a second stopper) erected on the base plate. For convenience of explanation, the stopper on the side where the elastic member is arranged will be referred to as a first stopper. The pressure that the stacked unit receives from the elastic member varies due to variations in the thickness of the semiconductor module and the cooler, and variations in the shape and elastic modulus of the elastic member. Therefore, in the power converter of Patent Document 1, a spacer is inserted between the first stopper and the elastic member. Prepare multiple types of spacers with different lengths in the stacking direction, and select appropriate spacers according to the variations in the stacked units (or elastic members) so that the pressure applied to the stacked units is within a predetermined pressure range. insert.

Japanese Patent Application Publication No. 2013-162541

Preparing a number of spacers with different lengths depending on variations in laminated units (or elastic members) increases costs. The present specification provides a technique that can reduce the number of spacers having different lengths in the stacking direction.

In the power converter disclosed in this specification, a laminated unit is sandwiched between a first stopper and a second stopper, and an elastic member and a spacer are sandwiched between the first stopper and the laminated unit. The first stopper includes a groove into which the spacer fits. The spacer includes a pair of first contact surfaces arranged in parallel with each other separated by a first distance, and a pair of second contact surfaces arranged in parallel separated by a second distance different from the first distance. ing. The width of the spacer when viewed from the normal direction of the first abutting surface is equal to the width of the spacer when viewed from the normal direction of the second abutting surface, and one of the first abutting surface and the second abutting surface is in contact with the bottom surface of the groove of the first stopper.

When one of the pair of first contact surfaces of the spacer contacts the bottom surface of the groove of the first stopper, the other first contact surface contacts the elastic member, and the spacer moves the elastic member from the first stopper to the first contact surface. It functions as a first spacer that separates the two by a certain distance. When one of the pair of second abutting surfaces of the spacer abuts the bottom surface of the groove, the other second abutting surface abuts the elastic member, and the spacer has a second contact surface that moves the elastic member away from the first stopper by a second distance. 2 functions as a spacer. Two lengths can be selected with one spacer. Furthermore, the width of the spacer when viewed from the normal direction from both the first abutment surface and the second abutment surface is the same. Regardless of whether the first contact surface or the second contact surface is used, the spacer fits into the groove of the first stopper, and the position of the spacer is determined.

The spacer described above is typically a rectangular parallelepiped. The rectangular parallelepiped has sides with three different lengths: length, width, and depth, and when the width is defined as the width of the spacer, the rectangular parallelepiped spacer has the vertical direction aligned with the stacking direction and the first stopper. The length of the spacer can be made different depending on whether it is inserted between the first stopper and the elastic body and when it is inserted between the first stopper and the elastic body with the depth direction matching the stacking direction.

By forming the spacer into a hexagonal column, it is possible to realize a spacer whose length can be selected from three types. Such a spacer has the following characteristics. The spacer includes a pair of third contact surfaces arranged in parallel and separated by a third distance that is different from both the first distance and the second distance. The width of the spacer when viewed from the normal direction of the third abutment surface is equal to the width of the spacer when viewed from the normal direction of the first abutment surface. That is, the width of the spacer when viewed from the normal direction of the third abutment surface is also equal to the width of the spacer when viewed from the normal direction of the second abutment surface. Any one of the first contact surface, the second contact surface, and the third contact surface of the spacer contacts the bottom surface of the groove of the first stopper.

In the case of a hexagonal prism, when one of the pair of third contact surfaces of the spacer contacts the bottom surface of the groove of the first stopper, the other third contact surface contacts the elastic member, and the spacer It functions as a third spacer that separates the first stopper by a third distance. One spacer can be used as three types of spacers (ie, first/second/third spacers). No matter which type is selected, since the width when viewed from the normal direction of the contact surface is the same, the spacer fits into the groove of the first stopper and the position of the spacer is determined.

When the spacer is a hexagonal column, it is preferable that one end of the hexagonal column in the axial direction is provided with a head that protrudes from all of the first contact surface, the second contact surface, and the third contact surface. When setting the spacer in the groove of the first stopper, the head comes into contact with the front end surface of the first stopper, and the position in the spacer insertion direction is determined.

Details and further improvements of the technology disclosed in this specification will be explained in the following "Detailed Description of the Invention".

FIG. 1(A) is a plan view of the power converter of the first embodiment. FIG. 1(B) is a side view of the power converter of the first embodiment. FIG. 3 is a perspective view of a spacer. FIG. 3(A) is an enlarged plan view of the area around the first stopper when the first surface is in contact with the first stopper. FIG. 4(B) is an enlarged plan view of the area around the first stopper when the second surface is in contact with the first stopper. FIG. 7 is an enlarged perspective view of the vicinity of the first stopper of the power converter of the second embodiment. FIG. 7 is a sectional view of a spacer of a power converter according to a second embodiment. FIGS. 6A to 6C are diagrams showing the distance between the first stopper and the compression spring when the first surface to the third surface are brought into contact with the first stopper, respectively.

(First Embodiment) A power converter 2 according to a first embodiment will be explained with reference to FIGS. 1 to 3. FIG. 1(A) shows a plan view of the power converter 2, and FIG. 1(B) shows a side view of the power converter 2. The power converter 2 is a device that is mounted on an electric vehicle and converts direct current power from a main battery into alternating current power suitable for driving a driving motor.

The power converter 2 includes a laminated unit 10. In FIG. 1, only the laminated unit 10 and the base plate 3 that supports it are shown, and illustration of other parts is omitted. The base plate 3 may be a part of the casing of the power converter 2.

The stacked unit 10 is a device in which a plurality of semiconductor modules 11 and a plurality of coolers 12 are alternately stacked. In FIG. 1, only the semiconductor modules at both ends of the figure are designated by the reference numeral 11, and the remaining semiconductor modules are not designated by the reference numerals. Similarly, in FIG. 1, only the coolers at both ends are labeled with numeral 12, and the remaining coolers are omitted. For convenience of explanation, the cooler 12 at the right end in the figure is indicated by the reference numeral 12a, and the cooler 12 at the left end is indicated by the reference numeral 12b. The X direction in the coordinate system of FIG. 1 corresponds to the stacking direction of the plurality of semiconductor modules 11 and the plurality of coolers 12. Hereinafter, the direction in which the plurality of semiconductor modules 11 and the plurality of coolers 12 are stacked will be simply referred to as the "stacking direction."

Two power conversion power transistors 19 (semiconductor elements), which are main components of the power converter 2, are embedded in each semiconductor module 11. The main body of the semiconductor module 11 is a resin package in which two power transistors 19 are embedded. Two power transistors 19 are connected in series inside the package. Three terminals that are electrically connected to the high potential side, the low potential side, and the middle point of the series connection of the power transistors 19 extend outside the package, but their illustration is also omitted. Control terminals that are electrically connected to the gate electrodes of the respective power transistors 19 are also omitted from illustration.

Returning to the explanation of the laminated unit 10. The plurality of coolers 12 are flat and arranged in parallel so that their wide surfaces face each other. A semiconductor module 11 is sandwiched between two adjacent coolers 12. The cooler 12 is provided with a refrigerant flow path inside. Two adjacent coolers 12 are connected by two connecting pipes 13a and 13b. In FIG. 1, only the connecting pipes at the left end are labeled with numerals 13a and 13b, and the remaining connecting pipes are omitted. The left end cooler 12b is provided with a refrigerant supply pipe 14a and a refrigerant discharge pipe 14b.

The refrigerant supply pipe 14a and the refrigerant discharge pipe 14b are connected to a refrigerant circulation device (not shown). The refrigerant supplied through the refrigerant supply pipe 14a is distributed to all the coolers 12 via one of the connecting pipes 13a. The refrigerant absorbs heat from adjacent semiconductor modules 11 while passing through the cooler 12 . The refrigerant that has absorbed the heat returns to the refrigerant circulation system through the other connecting pipe 13b and the refrigerant discharge pipe 14b.

The stacked unit 10 is supported by the base plate 3. A pair of first stoppers 4 and one second stopper 5 are provided on the base plate 3. As mentioned earlier, the base plate 3 may be part of the housing that houses the stacked unit 10, in which case the walls of the housing cover the first stopper 4 (and/or the second stopper 5). May also serve as both. The stacked unit 10 is arranged between the first stopper 4 and the second stopper 5 so that the stacking direction matches the direction in which the first stopper 4 and the second stopper 5 are lined up. Note that the X direction of the coordinate system in the figure indicating the stacking direction also corresponds to the direction in which the first stopper 4 and the second stopper 5 are arranged. The Y direction of the coordinate system in the figure corresponds to the direction in which the pair of first stoppers 4 are arranged.

A compression spring 6 is arranged between the cooler 12a and the first stopper 4 at one end in the stacking direction. The compression spring 6 urges the stacked unit 10 toward the second stopper 5 . In other words, the compression spring 6 presses the stacked unit 10 in the stacking direction. Due to the pressing force of the compression spring 6, the adjacent semiconductor modules 11 and the cooler 12 are brought into close contact with each other, and the cooling capacity for the semiconductor modules 11 is improved. The compression spring 6 is a plate spring made of steel. A reinforcing plate may be attached to the side of the leaf spring that contacts the cooler 12a.

The first stopper 4 is provided with a groove 4a on the surface facing the stacked unit 10, and the spacer 20 fits into the groove 4a. To aid understanding, in FIG. 1A, the spacer 20 that fits into the upper first stopper in the figure among the pair of first stoppers 4 is hatched in gray. Further, a spacer 20a that fits into the first stopper 4 on the lower side of the stopper diagram is drawn with a virtual line, and a groove 4a is illustrated.

If the pressure applied to the stacked unit 10 varies during mass production of the power converter 2, the cooling performance for the semiconductor module 11 will vary. During the manufacturing process, the spacer 20 is sandwiched between the compression spring 6 and the first stopper 4 so that the pressure applied to the stacked unit 10 by the compression spring 6 is within a predetermined range. Several spacers with different lengths are prepared on the manufacturing line of the power converter 2, and a spacer with an appropriate length is selected so that the pressure applied to the stacked unit 10 falls within a predetermined range. Preparing the same number of spacers as the lengths of the spacers increases the cost. The spacer 20 employed in the power converter 2 of the first embodiment can be used alone as a spacer with two different lengths. Next, the spacer 20 will be explained.

FIG. 2 shows a perspective view of the spacer 20. The spacer 20 is a rectangular parallelepiped, and the lengths of the sides in the X direction, Y direction, and Z direction of the coordinate system in the figure are L1, W, and L2, respectively. Length L1 and length L2 are different. A pair of parallel surfaces of the rectangular parallelepiped spacer 20 are referred to as first surfaces 21, another pair of parallel surfaces are referred to as second surfaces 22, and the remaining pair of parallel surfaces are referred to as third surfaces 23. The length W of the spacer 20 in the Y direction of the coordinate system in the figure is defined as the width of the spacer 20. In other words, the width of the spacer 20 when viewed from the normal direction (X direction) of the first surface 21 is equal to the width of the spacer 20 when viewed from the normal direction (Z direction) of the second surface 22. The length is W.

FIG. 3A shows a plan view when the spacer 20 is set between the first stopper 4 and the compression spring 6 with the first surface 21 facing the stacking direction. FIG. 3B shows a plan view when the spacer 20 is set between the first stopper 4 and the compression spring 6 with the second surface 22 facing the stacking direction. FIGS. 3A and 3B are enlarged views showing the periphery of only one of the pair of first stoppers 4. FIG. The structure around the other of the pair of first stoppers 4 is the same as in FIGS. 3(A) and 3(B). In FIG. 3 as well, the spacer 20 is hatched in gray to aid understanding.

Note that, as shown in FIG. 3A, the compression spring 6 has a fulcrum 6a that is closer to the spacer 20 in the stacking direction than the end 6b. The spacer 20 abuts on the fulcrum 6a. When inserting the spacer 20 between the first stopper 4 and the compression spring 6, the end 6b of the compression spring 6 is compressed toward the stacked unit 10 using a predetermined jig to secure a gap in which the spacer 20 is inserted. After inserting the spacer 20, the jig is removed so that the compression spring 6 is held between the spacer 20 and the laminated unit 10.

As shown in FIG. 3(A), one of the pair of first surfaces 21 (21a, 21b) (first surface 21a) is in contact with the bottom surface 4b of the groove 4a of the first stopper 4. At this time, the other (first surface 21b) of the pair of first surfaces 21 (21a, 21b) is in contact with the compression spring 6. A distance L1 is ensured between the fulcrum 6a of the compression spring 6 and the bottom surface 4b of the groove 4a of the first stopper 4. That is, the spacer 20 functions as a spacer having a length L1.

The spacer 20 is arranged between the compression spring 6 and the first stopper 4 with the third surface 23 facing the direction in which the pair of first stoppers 4 are arranged (the Y direction in the figure). The width of the groove 4a is equal to the length W between the pair of third surfaces 23 of the spacer 20 (see FIG. 2). Therefore, the spacer 20 with the first surface 21 facing the stacking direction and the third surface 23 facing the direction in which the first stoppers 4 are arranged fits into the groove 4a without a gap. By fitting the spacer 20 into the groove 4a, the position of the spacer 20 in the Y direction is determined.

In FIG. 3(B), one of the pair of second surfaces 22 (22a, 22b) (second surface 22a) is in contact with the bottom surface 4b of the groove 4a of the first stopper 4. At this time, the other (second surface 22b) of the pair of second surfaces 22 (22a, 22b) is in contact with the compression spring 6. A distance L2 is ensured between the fulcrum 6a of the compression spring 6 and the bottom surface 4b of the groove 4a of the first stopper 4. That is, the spacer 20 functions as a spacer having a length L2.

Also in the case of FIG. 3B, the spacer 20 is placed between the compression spring 6 and the first stopper 4 with the third surface 23 facing the direction in which the pair of first stoppers 4 are arranged (the Y direction in the figure). Placed. Therefore, the spacer 20 with the second surface 22 facing the stacking direction and the third surface 23 facing the direction in which the first stoppers 4 are arranged fits into the groove 4a without a gap. Also in the case of FIG. 3(B), the position of the spacer 20 in the Y direction is determined by fitting the spacer 20 into the groove 4a.

As described above, the rectangular parallelepiped spacer 20 is set between the compression spring 6 and the first stopper 4 with the first surface 21 facing the stacking direction, and when it is set with the second surface 22 facing the stacking direction. In cases, different lengths act as spacers. No matter which length the spacer is used as, the spacer 20 fits into the groove 4a provided in the first stopper 4 without a gap, and the position of the spacer 20 in the Y direction is determined. Although it is preferable that there is no gap between the spacer 20 and the groove 4a, there may be a gap.

(Second Embodiment) Next, a power converter 2a of a second embodiment will be explained with reference to FIGS. 4 to 6. FIG. 4 is an enlarged perspective view of the vicinity of the first stopper 4 in the power converter 2a. The power converter 2a of the second embodiment has the same structure as the power converter 2 of the first embodiment except for the shape of the spacer 120. Therefore, explanations other than the structure of the spacer 120 will be omitted.

The spacer 120 includes a hexagonal columnar main body 121 and a head 122 provided at one end (upper end) of the main body 121 in the columnar axis direction (Z direction). FIG. 5 shows a cross section of the main body 121 cut along a plane intersecting the column axis.

The hexagonal columnar main body 121 has six side surfaces. The six side surfaces include a pair of parallel first surfaces 21, a pair of parallel second surfaces 22, and a pair of parallel third surfaces. The distance L1 between the pair of first surfaces 21, the distance L2 between the pair of second surfaces 22, and the distance L3 between the pair of third surfaces are different from each other. Also, the width W1 of the main body 121 when viewed from the normal direction of the first surface 21, the width W2 of the main body 121 when viewed from the normal direction of the second surface 22, and the width W2 of the main body 121 when viewed from the normal direction of the third surface 23. The width W3 of the main body 121 at this time is the same width W.

Returning to FIG. 4, the explanation will be continued. The spacer 120 is arranged such that one of the first surface 21, the second surface 22, and the third surface 23 contacts the bottom surface 4b of the groove 4a of the first stopper 4. Note that the width of the groove 4a is the length W, and even when any of the first surface 21, the second surface 22, and the third surface 23 is brought into contact with the bottom surface 4b, the main body 121 is It fits into the groove 4a without any gap in the Y direction of the coordinate system. With this structure, the position of the spacer 120 in the Y direction is accurately determined even when any of the first surface 21, the second surface 22, and the third surface 23 is brought into contact with the bottom surface 4b.

Further, the head 122 is located at one end of the hexagonal columnar main body 121 in the column axis direction, and protrudes from any of the first surface 21, second surface 22, and third surface 23 of the main body 121 in the normal direction. There is. Regardless of which of the first surface 21, second surface 22, and third surface 23 is brought into contact with the bottom surface 4b, the spacer 120 is placed in the groove 4a along the -Z direction of the coordinate system in the figure. When inserted, the head 122 comes into contact with the distal end surface 4c of the first stopper 4, and the position of the spacer 120 in the Z direction is accurately determined.

6(A) to (C), the spacer 120 is compressed by bringing the first surface 21/second surface 22/third surface 23 of the main body 121 into contact with the bottom surface 4b of the groove 4a of the first stopper 4. An enlarged plan view when set between the spring 6 and the first stopper 4 is shown. In FIG. 6, illustration of the laminated unit is omitted.

In the case of FIG. 6A, one of the pair of first surfaces 21 (21a, 21b) (first surface 21a) is in contact with the bottom surface 4b of the groove 4a of the first stopper 4. At this time, the other (first surface 21b) of the pair of first surfaces 21 (21a, 21b) is in contact with the compression spring 6. A distance L1 is ensured between the fulcrum 6a of the compression spring 6 and the bottom surface 4b of the groove 4a of the first stopper 4. That is, the spacer 120 functions as a spacer having a length L1. Further, as described above, since the width W1 of the main body 121 when viewed from the normal direction of the first surface 21 is equal to the width W of the groove 4a, the main body 121 fits into the groove 4a without any gap. The position of the spacer 120 in the Y direction is determined accurately.

In the case of FIG. 6(B), one of the pair of second surfaces 22 (22a, 22b) (second surface 22a) is in contact with the bottom surface 4b of the groove 4a of the first stopper 4. At this time, the other (second surface 22b) of the pair of second surfaces 22 (22a, 22b) is in contact with the compression spring 6. A distance L2 is ensured between the fulcrum 6a of the compression spring 6 and the bottom surface 4b of the groove 4a of the first stopper 4. That is, the spacer 120 functions as a spacer having a length L2. Further, as described above, since the width W2 of the main body 121 when viewed from the normal direction of the second surface 22 is equal to the width W of the groove 4a, the main body 121 fits into the groove 4a without any gap. The position of the spacer 120 in the Y direction is determined accurately.

In the case of FIG. 6C, one of the pair of third surfaces 23 (23a, 23b) (third surface 23a) is in contact with the bottom surface 4b of the groove 4a of the first stopper 4. At this time, the other (third surface 23b) of the pair of third surfaces 23 (23a, 23b) is in contact with the compression spring 6. A distance L3 is ensured between the fulcrum 6a of the compression spring 6 and the bottom surface 4b of the groove 4a of the first stopper 4. That is, the spacer 120 functions as a spacer having a length L3. Further, as described above, since the width W3 of the main body 121 when viewed from the normal direction of the third surface 23 is equal to the width W of the groove 4a, the main body 121 fits into the groove 4a without any gap. The position of the spacer 120 in the Y direction is determined accurately.

As described above, one spacer 120 is set between the compression spring 6 and the first stopper 4 with the first surface 21 facing the stacking direction, and when set with the second surface 22 facing the stacking direction. The spacer functions as a spacer of different length depending on whether it is set with the third surface 23 facing the stacking direction. By realizing one spacer having three types of lengths, it is possible to reduce the cost required to prepare spacers of different lengths.

Regardless of the length of the spacer, the spacer 120 fits into the groove 4a provided in the first stopper 4 without a gap, and the position in the Y direction is accurately determined. Note that there may be a gap between the spacer 120 and the groove 4a. Moreover, the position of the spacer 120 in the Z direction is also accurately determined by the head 122 coming into contact with the distal end surface 4c (see FIG. 4) of the first stopper 4.

Points to note regarding the techniques described in the examples will be described. The first surface 21 corresponds to a first contact surface, and the second surface 22 corresponds to a second contact surface. The third surface 23 corresponds to the third contact surface. The head 122 corresponds to an example of a protrusion provided at one end of the hexagonal columnar main body 121. The compression spring 6 corresponds to an example of an elastic body.

Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The techniques described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims as filed. Furthermore, the techniques illustrated in this specification or the drawings can achieve multiple objectives simultaneously, and achieving one of the objectives has technical utility in itself.

2, 2a: Power converter 3: Base plate 4: First stopper 4a: Groove 4b: Bottom surface 4c: Tip surface 5: Second stopper 6: Compression spring 10: Laminated unit 11: Semiconductor module 12, 12a, 12b: Cooling 19: Power transistor 20, 20a, 120: Spacer 21, 21a, 21b: First surface 22, 22a, 22b: Second surface 23, 23a, 23b: Third surface 121: Main body 122: Head

Claims (2)

a stacked unit in which a plurality of semiconductor modules housing semiconductor elements and a plurality of coolers are stacked;
a base plate on which a first stopper and a second stopper are erected, and the laminated unit is arranged between the first stopper and the second stopper;
an elastic member that is inserted between the first stopper and the laminated unit and biases the laminated unit toward the second stopper;
a spacer inserted between the first stopper and the elastic member;
It is equipped with
The first stopper includes a groove into which the spacer fits,
The spacer includes a pair of first contact surfaces arranged in parallel with a first distance apart, and a pair of second contact surfaces arranged in parallel with a second distance different from the first distance. and a pair of third contact surfaces arranged in parallel with a third distance different from both the first distance and the second distance,
It is equipped with
The width of the spacer when viewed from the normal direction of the first abutment surface , the width of the spacer when viewed from the normal direction of the second abutment surface , and the normal direction of the third abutment surface. The widths of the spacers when viewed from above are equal,
A power converter , wherein one of the first contact surface, the second contact surface, and the third contact surface is in contact with a bottom surface of the groove of the first stopper. The spacer is a hexagonal column, and has a head at one end thereof that protrudes from each of the first contact surface, the second contact surface, and the third contact surface, and the head is attached to the first contact surface. The power converter according to claim 1 , wherein the power converter comes into contact with the tip end surface of the stopper.

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