JP2015130735A - Electric power conversion system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that connects refrigerant pipes of coolers with each other at low costs in an electric power conversion system including two pairs of power converters and coolers for cooling the power converters.SOLUTION: An electric power conversion system 2 includes: a first housing 3 storing a lamination cooling unit 20; and a second housing 4 which stores a step-down converter 75 and a cooler 5 and is integrated with the first housing 3. A first protruding part 13 is provided on a side wall of the first housing 3 that is located adjacent to a coupling surface coupled to the second housing 4. A second protruding part 14 which is coupled to the first protruding part 13 when the second housing 4 is integrated with the first housing 3 is provided on a side wall of the second housing 4. A first refrigerant passage P1 is provided in the first protruding part 13, and a refrigerant pipe 23 of the lamination cooling unit 20 is connected with one end of the first refrigerant passage P1. A second refrigerant passage P2 is provided in the second protruding part 14, and a refrigerant pipe 6 of the cooler 5 is connected with one end of the second refrigerant passage P2. The first refrigerant passage P1 and the second refrigerant passage P2 communicate with each other in a housing 6 formed by the first housing 3 and the second housing 4 integrated with each other.

Description

  The present invention relates to a power conversion device. The power conversion device disclosed in the present specification is particularly suitable for a vehicle-mounted power conversion device that converts battery power and supplies it to a traveling motor.

  A power converter that outputs a large amount of power includes many heat generating components. Typically, a vehicle-mounted power conversion device that converts battery power and supplies it to a motor for travel includes a large number of switching elements that generate a large amount of heat. Many power converters include a plurality of power converters such as a voltage converter circuit and an inverter circuit, or a plurality of voltage converter circuits. The power converter includes a heat generating component such as a number of switching elements.

  When the power converter includes a large number of heat generating components, a liquid cooling type cooler may be provided to cool the heat generating components. And in a power converter device provided with a plurality of power converters, a cooler may be provided for every power converter. Patent Document 1 discloses a power conversion device that includes two power converters and a liquid-cooled cooler that cools each power converter. In the power converter, a connecting pipe that connects two coolers is exposed to the outside of the apparatus housing. The reason why the connecting pipe must be provided outside the apparatus housing is, for example, a demand for downsizing the apparatus housing.

  In the power conversion device of Patent Document 1, the refrigerant pipe of one cooler and the refrigerant pipe of the other cooler protrude from the housing side wall, and the two refrigerant pipes are connected by a connecting pipe. The connecting pipe is, for example, a hose made of EPDM, NBR or the like that has elasticity and also has insulating properties.

JP 2012-210022 A

  As in the power conversion device of Patent Document 1, a connecting member is required to connect the refrigerant pipes extending from the two coolers outside the housing. The present specification relates to a power conversion device having two sets of a power converter and a cooler for cooling the power converter, and provides a technique for connecting the refrigerant pipes of the respective coolers at low cost.

  In a power conversion device incorporating a plurality of power converters, a mode in which a casing is divided and each of the power converters is accommodated may be employed. The technology disclosed in the present specification uses the divided housings skillfully to connect the refrigerant tubes of the two coolers at a low cost.

  A power converter disclosed in the present specification includes a first power converter, a first housing that houses a liquid-cooled first cooler that cools the first power converter, a second power converter, and the first power converter A second housing that houses a liquid-cooled second cooler that cools the second power converter is provided. The first housing and the second housing are combined to form one housing. The first casing is provided with a first protrusion on the side wall adjacent to the coupling surface with the second casing. The second casing is provided with a second protrusion that is coupled to the first protrusion when the first casing is combined with the first casing. And the 1st refrigerant | coolant flow path is provided in the inside of the 1st protrusion part, and the refrigerant | coolant pipe | tube of a 1st cooler is connected with the end of the 1st refrigerant | coolant flow path. A second refrigerant flow path is provided inside the second protrusion, and a refrigerant pipe of the second cooler is connected to one end of the second refrigerant flow path. And in the housing | casing which the 1st housing | casing and the 2nd housing | casing united, the 1st protrusion part and the 2nd protrusion part couple | bond together, and a 1st refrigerant | coolant flow path and a 2nd refrigerant | coolant flow path are connected.

In the above power conversion device, a refrigerant flow path is provided in a part of each casing, and when the two casings are combined, the two refrigerant flow paths are connected. Therefore, it is not necessary to prepare a connecting pipe separately, and the two coolers can be connected at low cost. In general, the casing of the in-vehicle power converter is often made of a metal such as aluminum. In that case, the first protrusion can be formed integrally with the first casing. Since the first protrusion can be provided in the housing manufacturing process, the cost can be further suppressed. The same applies when the housing is made of resin. The same applies to the second protrusion of the second housing.

  The present specification relates to a power conversion device having two sets of a power converter and a cooler for cooling the power converter, and provides a technique for connecting the refrigerant pipes of the respective coolers at low cost. Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a disassembled perspective view of the power converter device of an Example. It is a perspective view of a power converter (state where a cover was removed). It is sectional drawing in the III-III line of FIG. FIG. 4 is an enlarged cross-sectional view of a portion indicated by a broken line IV in FIG. 3. It is an expanded sectional view of the power converter of a modification.

  The power conversion device 2 will be described with reference to the drawings. FIG. 1 is an exploded perspective view of the power conversion device 2, and FIG. 2 is a perspective view of the power conversion device 2. In addition, in order to assist an understanding, illustration of the cover of the power converter device 2 is omitted. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2 (a cross-sectional view vertically crossing the first protrusion 13 and the second protrusion 14). In FIG. 3, a cover 3a is depicted.

  The power conversion device 2 is mounted on an electric vehicle, boosts DC power of a main battery (not shown), converts it to AC, and supplies the AC to a traveling motor. The power conversion device 2 also has a function of reducing the power of the main battery and supplying power to the auxiliary battery and the auxiliary machine group. The electric power converter 2 includes, as an electric circuit, a circuit that combines a voltage converter circuit and an inverter circuit, and a step-down converter circuit. The power conversion device 2 mainly includes a stacked cooling unit 20 that integrates and cools switching elements (transistors such as IGBTs) of a voltage converter circuit and an inverter circuit as hardware, and a smoothing that smoothes a large current for driving a motor. The capacitor 77, the reactor 77 used in the voltage converter circuit, the step-down converter 75 for stepping down the power of the main battery, the cooler 5 for cooling the step-down converter 75, and the circuit board on which the control circuit for controlling the switching element is mounted. Is done. Although the circuit board is disposed above the stacked cooling unit 20 and the reactor 77, the illustration thereof is omitted.

  A housing 6 of the power conversion device 2 that houses the hardware group is divided into a first housing 3 and a second housing 4. In other words, the first housing 3 and the second housing 4 are combined to form one housing 6 of the power conversion device 2. The first casing 3 accommodates the multilayer cooling unit 20, the reactor 77, the smoothing capacitor 76, and a circuit board (not shown). The second casing 4 houses a step-down converter 75. The bottom plate of the first housing 3 corresponds to the cover of the second housing 4. The second casing 4 is provided with a refrigerant pipe 7 (see FIG. 3), and the second casing 4 itself corresponds to the cooler 5.

  A first protrusion 13 is provided on the side wall of the first housing 3, and a first refrigerant flow path P <b> 1 is formed therein. Moreover, the 2nd protrusion part 14 is provided in the side wall of the 2nd housing | casing 4, and the 2nd refrigerant | coolant flow path P2 is formed in the inside. When the 1st housing | casing 3 and the 2nd housing | casing 4 unite, the 1st refrigerant | coolant flow path P1 and the 2nd refrigerant | coolant flow path P2 will connect (refer FIG. 2, FIG. 3). The first and second protrusions 13 and 14 and the first and second refrigerant flow paths P1 and P2 will be described in detail later.

  The structure of the stacked cooling unit 20 will be outlined. The stacked cooling unit 20 is formed by alternately stacking a plurality of power cards 22 molded with switching elements and a plurality of flat plate-shaped cooling plates 21 through which a refrigerant passes. A large number of switching elements included in the stacked cooling unit 20 correspond to main components of the voltage converter circuit and the inverter circuit.

  The cooling plate 21 is hollow inside, and through holes are provided on both sides in the longitudinal direction (that is, both sides of the power card 22). The through holes of adjacent cooling plates 21 are connected by a connecting pipe 25. In addition, two refrigerant tubes 23 and 24 are connected to the cooling plate 21 positioned at the end of the stacked cooling unit 20 in the stacking direction. The stacked cooling unit 20 is housed in the first housing 3. The laminated cooling unit 20 is further laminated with an insulating plate 81 and a leaf spring 79 at one end of the laminated body, and is sandwiched and supported by the inner wall of the first housing 3 and the support 78. The laminated cooling unit 20 is supported by the first casing 3 by the leaf spring 79 while applying a load in the laminating direction. Due to the load of the leaf spring 79, the alternately stacked cooling plates 21 and the power card 22 are brought into close contact with each other, and heat is well transmitted between them.

  One refrigerant pipe 23 connected to the cooling plate 21 positioned at the end in the stacking direction of the stacked cooling unit 20 is connected to the first refrigerant flow path P1 provided on the side wall of the first housing 3, The other refrigerant pipe 24 is connected to an external refrigerant discharge pipe 72 through a through hole 73 provided in the side wall of the first housing 3.

  A step-down converter 75 is accommodated in the second housing 4. As described above, the second housing 4 itself constitutes the cooler 5 and cools the step-down converter 75. A refrigerant pipe 7 is formed inside the second housing 4. One end of the refrigerant pipe 7 is connected to a second refrigerant flow path P <b> 2 provided in the second protrusion 14 of the second housing 4. The other end of the refrigerant pipe 7 is connected to an external refrigerant supply pipe 71 through an opening 74 provided on the side wall of the second housing 4.

  As described above, the power conversion device 2 has two sets of power converters and coolers built therein. One set is a stacked cooling unit 20 in which a power converter and a cooler are integrated, and the other set is a step-down converter 75 and a cooler 5. As described above, the cooler 5 is the second housing 4 itself.

  The flow of the refrigerant in the power conversion device 2 will be described. The refrigerant is, for example, water or LLC (Long Life Coolant). The refrigerant is supplied from the outside to the power converter 2 through the refrigerant supply pipe 71. The refrigerant supplied through the refrigerant supply pipe 71 flows into the refrigerant pipe 7 (see FIG. 3) of the cooler 5 through the opening 74. The refrigerant cools the step-down converter 75 while flowing through the refrigerant pipe 7, that is, the cooler 5. The other end of the refrigerant pipe 7 is connected to the second refrigerant flow path P2. The second refrigerant flow path P2 communicates with the first refrigerant flow path P1, and the first refrigerant flow path P1 is connected to the refrigerant pipe 23 of the stacked cooling unit 20. Therefore, the refrigerant that has passed through the refrigerant pipe 7 (that is, the cooler 5) flows to the stacked cooling unit 20 through the second refrigerant flow path P2 and the first refrigerant flow path P1. In the laminated cooling unit 20, the refrigerant is distributed to all the cooling plates 21 through the refrigerant pipe 23 and the connecting pipe 25. The refrigerant cools each power card in contact with the cooling plate 21 while flowing through each cooling plate 21. The refrigerant that has passed through the cooling plate 21 is discharged to the external refrigerant discharge pipe 72 that is connected to the housing 6 of the power conversion device 2 through the opposite connection pipe 25 and the refrigerant pipe 24.

  Referring to FIG. 4 together with FIG. 1 to FIG. 3, the first protrusion 13, the second protrusion 14, and the first refrigerant flow path P <b> 1 and the second refrigerant flow path P <b> 2 formed therein are shown. explain. 4 is an enlarged cross-sectional view of a range indicated by a broken line IV in FIG. In FIG. 4, the power card 22 is drawn with a virtual line to help understanding.

  As described above, the first protrusion 13 is provided on the side wall of the first housing 3, and the second protrusion 14 is provided on the side wall of the second housing 4. As well represented in FIGS. 1 and 2, the bottom surface of the first housing 3 serves as a coupling surface with the second housing 4. The first protrusion 13 is provided on the side wall adjacent to the coupling surface (that is, the bottom surface) of the first housing 3 with the second housing 4. The side wall adjacent to the coupling surface (bottom surface) is, in other words, a side wall continuous with the edge of the coupling surface (bottom surface). The first refrigerant flow path P <b> 1 is formed inside the first protrusion 13. One end 13 b of the first refrigerant flow path P <b> 1 opens to the inside of the first housing 3. A refrigerant pipe 23 of the stacked cooling unit 20 is connected to one end 13b of the first refrigerant flow path P1 via a round grommet 17. The first refrigerant flow path P <b> 1 is curved at right angles inside the first protrusion 13, and the other end is open to the bottom surface 13 a of the first protrusion 13.

  The second protrusion 14 is provided on the side wall of the second housing 4. A second refrigerant flow path P <b> 2 is formed inside the second protrusion 14. As described above, the second casing 4 itself is the cooler 5, and the second refrigerant flow path P <b> 2 is continuous with the refrigerant pipe 7 of the cooler 5. In other words, the second refrigerant flow path P <b> 2 is connected to the refrigerant pipe 7 of the cooler 5. The second refrigerant flow path P <b> 2 is curved at right angles inside the second projecting portion 14, and one end thereof opens to the upper surface 14 a of the second projecting portion 14.

  The 2nd protrusion part 14 is provided so that it may couple | bond with the 1st protrusion part 13 when the 1st housing | casing 3 and the 2nd housing | casing 4 unite | combine. More specifically, when the first housing 3 and the second housing 4 are combined, the bottom surface 13a of the first protrusion 13 is coupled to the upper surface 14a of the second protrusion 14. Then, the first refrigerant flow path P1 and the second refrigerant flow path P2 communicate with each other. Although omitted in FIG. 1, as shown in FIGS. 3 and 4, an O-ring 16 is disposed on the upper surface 14 a of the second protrusion 14 so as to surround the opening of the second refrigerant flow path P <b> 2. Has been. The O-ring 16 prevents the refrigerant from leaking from the boundary between the first refrigerant flow path P1 and the second refrigerant flow path P2 when the first protrusion 13 and the second protrusion 14 are combined.

  The advantages of the power conversion device 2 having the above structure will be described. The power conversion device 2 includes two sets of a power converter and a cooler that cools the power converter. One is a stacked cooling unit 20 in which a power converter and a cooler are integrated, and the other is a step-down converter 75 and a cooler 5 that cools it. The refrigerant pipes of the two coolers communicate with each other through refrigerant flow paths (first refrigerant flow path P1 and second refrigerant flow path P2) provided on the side wall of the housing 6. The first refrigerant flow path P <b> 1 is formed inside the first protrusion 13 provided on the side wall of the first housing 3. The second refrigerant flow path P <b> 2 is formed inside the second protrusion 14 provided on the side wall of the second housing 4. If the 1st housing | casing 3 and the 2nd housing | casing 4 unite, the 1st protrusion part 13 and the 2nd protrusion part 14 will also couple | bond together and the 1st refrigerant | coolant flow path P1 and the 2nd refrigerant | coolant flow path P2 will connect. With this structure, the refrigerant pipes of the two coolers can be communicated without using the space inside the housing. Therefore, the space inside the housing can be used effectively, for example, allocated to the accommodation of other electric devices. In other words, it is not necessary to provide a space for arranging the connecting portion of the first cooler (stacked cooling unit 20) and the second cooler (cooler 5) in the housing, so that the housing can be downsized. Can do. The connection part of the first cooler (stacked cooling unit 20) and the second cooler (cooler 5) is in the form of protrusions (first protrusion 13 and second protrusion 14) provided on the side wall of the housing. Although it is realized, when the connecting portion is provided inside, it is more space efficient to provide the protruding portion as compared with the fact that the entire housing must be increased in size.

  Further, the above structure can communicate the refrigerant pipes of the two coolers without providing another part such as another refrigerant pipe joint outside the casing, and without using a space inside the casing. . Therefore, it can be realized at low cost. In addition, since the first refrigerant flow path P1 and the second refrigerant flow path P2 are formed inside the protruding portion integrated with the casing, they can be simultaneously formed when the casing is manufactured.

  Furthermore, since the first refrigerant flow path P1 and the second refrigerant flow path P2 are formed in the protrusions (the first protrusion 13 and the second protrusion 14) that are integrated with the casing, The strength is higher than when a refrigerant pipe joint or the like is used. The housing of the in-vehicle device must take into account safety in the event of a collision. In that sense, the above-described structure capable of realizing the refrigerant flow path with high strength is suitable as a vehicle-mounted casing.

  Previously, it has been described that the projecting portions (the first projecting portion 13 and the second projecting portion 14) can be molded simultaneously with the housings (the first housing 3 and the second housing 4). This point will be supplemented. The first protrusion 13 is a part of the first housing 3. The first housing 3 including the first protrusion 13 is made by injection molding of aluminum. The second protrusion 14 is a part of the second housing 4. The 2nd housing | casing 4 containing the 2nd protrusion part 14 is also made by the injection molding of aluminum. A structure of a housing suitable for forming an L-shaped flow path by metal (aluminum) injection molding will be described. FIG. 5 is an enlarged cross-sectional view of the vicinity of the protruding portion of the power conversion device 2a according to the modification. Similar to the power conversion device 2 illustrated in FIGS. 1 to 4, the first casing 103 is provided with a first protrusion 113, and the second casing 104 is provided with a second protrusion 114. The 1st protrusion part 113 (2nd protrusion part 114) is the same as the 1st protrusion part 13 (2nd protrusion part 14) of FIGS. 1-4 except the point which has the hole 113c (114c).

  The hole 113 c is a hole for facilitating injection molding of the first housing 103. That is, at the time of injection molding, the first protrusion 113 is injection molded so as to have a straight through hole from the hole 113c to the opening 113b. That is, as an injection molding die, a slide die that moves in the X-axis direction in the drawing for making a straight through hole from the hole 113c to the opening 113b, and a Z-axis for making the remaining portion of the first refrigerant flow path P1. The first refrigerant flow path P1 can be formed with a lower mold having a protruding portion in the direction. The hole 113c is later sealed with a rubber plug 18.

  The same applies to the hole 114c, which is a hole for facilitating injection molding, and is sealed with a rubber plug 18 after molding. In the figure, the right side of the second protrusion 114 in the drawing is depicted as if the second housing 104 is solid, but this is because the interior of the second housing 104 is simplified. by. Actually, like the first housing 103, the second housing 104 also has a side wall, and the second protrusion 114 is also formed with a through hole extending from the hole 114c in the X-axis direction in the drawing.

  Points to be noted regarding the technology described in the embodiments will be described. The stacked cooling unit 20 corresponds to an example of a first power converter and a first cooler. The step-down converter 75 corresponds to an example of a second power converter. The cooler 5 corresponds to an example of a second cooler. The first refrigerant channel P1 and the second refrigerant channel P2 may have other shapes. Similarly, the first protrusion 13 and the second protrusion 14 may have other shapes.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2, 2a: power conversion device 3, 103: first housing 3a: cover 4, 104: second housing 5: cooler (second cooler)
6: Housing 7: Refrigerant tube 13, 113: First protrusion 13a: Bottom surface 13b: One end 14, 114: Second protrusion 14a: Upper surface 16: O-ring 17: Round grommet 18: Rubber stopper 20: Laminate cooling unit (First power converter, first cooler)
21: Cooling plate 22: Power card 23, 24: Refrigerant pipe 25: Connection pipe 71: Refrigerant supply pipe 72: Refrigerant discharge pipe 73: Through hole 74: Opening 75: Step-down converter (second power converter)
76: smoothing capacitors 113c, 114c: hole P1: first refrigerant flow path P2: second refrigerant flow path

Claims (1)

A first housing that houses a first power converter and a liquid-cooled first cooler that cools the first power converter; a liquid-cooled that cools the second power converter and the second power converter; A power converter comprising a second housing that contains the second cooler and is united with the first housing,
A first protrusion is provided on a side wall of the first casing adjacent to the coupling surface with the second casing;
A second protrusion that is coupled to the first protrusion when the first casing is combined with the side wall of the second casing;
A first refrigerant flow path is provided inside the first protrusion, and a refrigerant pipe of the first cooler is connected to one end of the first refrigerant flow path;
A second refrigerant flow path is provided inside the second protrusion, and a refrigerant pipe of the second cooler is connected to one end of the second refrigerant flow path;
The first refrigerant channel and the second refrigerant channel communicate with each other in a case where the first case and the second case are combined;
The power converter characterized by the above-mentioned.

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