JP2016127774A - Power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for achieving downsizing and reduction in weight, for a power converter in which a laminate formed by laminating a plurality of power cards and a plurality of coolers is pressurized.SOLUTION: A power converter 100 comprises a plurality of power cards 5, a plurality of coolers 3 and two stationary plates 7a and 7b. The two plates 7a and 7b are disposed at both ends of a laminate 2 that is formed by laminating the plurality of power cards 5 and the plurality of coolers 3. The laminate 2 and the two stationary plates 7a and 7b include through-holes that communicate in a direction of lamination. Bolts 11a and 11b are inserted into the through-holes of the laminate 2 and the two stationary plates 7a and 7b, and the bolts 11a and 11b are fastened by nuts 15a and 15b. The bolts 11a and 11b pressurize the laminate 2 in the direction of lamination.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power converter. In particular, the present invention relates to a power converter having a stacked body in which a plurality of power cards containing semiconductor elements and a plurality of coolers are stacked.

  The power converter includes a large number of semiconductor elements called power semiconductor elements. For example, in a power converter that supplies power to a device that consumes a large amount of power, such as a motor for an electric vehicle, a semiconductor element generates a large amount of heat. For example, Patent Documents 1 and 2 disclose power converters that can efficiently cool a large number of semiconductor elements. The power converter disclosed in Patent Document 1 is mounted on an electric vehicle. The power converter converts the electric power of the battery into electric power for driving the traveling motor. The power converter includes a stacked body in which a plurality of power cards containing semiconductor elements and a plurality of coolers are stacked. Each cooler is stacked so as to be in contact with each power card. Since the power converter has a cooler in contact with each power card, a large number of semiconductor elements can be integrated and efficiently cooled. In the power converter disclosed in Patent Document 2, a leaf spring presses the stacked body of the power card and the cooler in the stacking direction in order to improve the adhesion between the power card and the cooler. The laminate is supported while being pressed between the inner surface of the housing of the power converter and the leaf spring.

JP2013-121236A JP 2012-231591 A

  In the power converter of patent document 2, in order to hold | maintain while pressing a laminated body within a housing, a leaf | plate spring is required. Further, the housing needs a space for fixing the leaf spring. The present specification eliminates the need for a space for fixing the above-described leaf spring and leaf spring for a power converter in which a laminated body in which a plurality of power cards and a plurality of coolers are stacked is pressed. Provide technology to achieve small size and light weight.

  The power converter disclosed in this specification includes a plurality of power cards, a plurality of coolers, and two plates. Each of the plurality of power cards accommodates a semiconductor element. The plurality of coolers are stacked with a plurality of power cards, and each cooler is in contact with each of the plurality of power cards. Two boards are arrange | positioned at the both ends of the lamination direction of the laminated body on which the several power card and the several cooler are laminated | stacked. The laminated body and the two plates are provided with through holes that communicate with each other in the laminating direction. Bundling rods are inserted into the through holes of the laminate and the two plates. The binding rod is fastened to each of the plates on both sides in the stacking direction. The binding rod pressurizes the stacked body in the stacking direction. According to such a structure, compared with the structure using the housing mentioned above and the structure using a band, a power converter can be reduced in size and weight.

It is a perspective view of the power converter of 1st Example. It is a rear view of a power converter. It is a perspective view of a power card. It is a disassembled perspective view of a cooler. It is a perspective view of the power converter of 2nd Example.

(First embodiment)
The power converter according to the first embodiment will be described with reference to the drawings. FIG. 1 is a perspective view of the power converter 100. The power converter 100 according to the embodiment is a device that is mounted on an electric vehicle and converts DC power of a battery into AC power for driving a traveling motor. The power converter 100 includes a voltage converter that boosts the output voltage of the battery, and an inverter that converts the boosted direct current into alternating current and supplies the alternating current to the traveling motor. The voltage converter and the inverter include a large number of switching elements (semiconductor elements) that generate a large amount of heat. The power converter 100 can efficiently cool these aggregated switching elements. In addition, in an Example, the power card which accommodates the switching element (semiconductor element), the cooler which cools the power card, and the bolt which connects them are explained, and explanation and illustration are shown about other parts. Omitted.

  As shown in FIG. 1, the laminated body 2 is a laminate of a plurality of power cards 5a-5d and a plurality of coolers 3a-3e. The direction of the X axis in the figure corresponds to the stacking direction. The same applies to the subsequent drawings. Hereinafter, when any one of the plurality of power cards 5a-5d is shown without distinction, it is referred to as “power card 5”. Further, when any one of the plurality of coolers 3a to 3e is shown without distinction, it is referred to as “cooler 3”. In the following description, for convenience of explanation, the positive direction of the Z axis may be referred to as “up”, the negative direction as “down”, the positive direction of the X axis as “front”, and the negative direction as “rear”. Further, the Y-axis direction may be referred to as “lateral direction”.

  The plurality of power cards 5 and the plurality of coolers 3 are alternately stacked one by one. The cooler 3 is in contact with both sides of each power card 5. In the coolers 3a and 3e at both ends in the stacking direction of the stacked body 2, the power card 5 is in contact with only one surface. A front end cover 4 a having a refrigerant supply pipe 91 and a refrigerant discharge pipe 92 is attached to the surface of the cooler 3 a that is not in contact with the power card 5. A rear end cover 4b is attached to the surface of the cooler 3e where the power card 5 is not in contact. A fixing plate 7a for fixing a bolt is attached to the surface of the front end cover 4a that is not in contact with the cooler 3a. The fixing plate 7 a has holes at positions corresponding to the refrigerant supply pipe 91 and the refrigerant discharge pipe 92. That is, the refrigerant supply pipe 91 and the refrigerant discharge pipe 92 protrude from the fixed plate 7a. A fixing plate 7b for fixing the bolt is attached to the surface of the rear end cover 4b that is not in contact with the cooler 3e. Each power card 5 and each cooler 3 are in a temporarily assembled state until the bolt is attached.

  As will be described in detail later, each cooler 3 has two types of through holes. The first type of through holes are located at both ends in the Y-axis direction in the figure. The first type through-hole penetrates the cooler 3 in the stacking direction (X-axis direction). The first type of through hole is connected to the flow path extending in parallel with the power card 5 inside the cooler 3. The refrigerant supplied from the refrigerant supply pipe 91 provided in the front end cover 4a is distributed to all the coolers through one first-type through hole. The refrigerant is a liquid, typically water or LLC (Long Life Coolant). The refrigerant absorbs heat from the adjacent power card 5 while passing through the flow path of each cooler 3. Thereafter, the refrigerant is discharged from a refrigerant discharge pipe 92 provided in the front end cover 4a through the other first type through hole. The second type of through-holes are located at both ends in the Y-axis direction in the drawing and at the ends of the first type of through-holes. The second type through hole also penetrates the cooler 3 in the stacking direction (X-axis direction). The front end cover 4a, the rear end cover 4b, and the fixing plates 7a and 7b have through holes at positions that communicate with the second type through holes. Bolts are inserted into the second type through holes and fastened with nuts, whereby the laminate 2 is pressed in the laminating direction.

  The structure of the power card 5 will be described. FIG. 3 shows a perspective view of the power card 5. The power card 5 is a device in which semiconductor elements 52 a and 52 b are sealed with a resin package 51. The semiconductor elements 52 a and 52 b are transistors (IGBT), and are connected in series inside the package 51. Hereinafter, the series connection of the semiconductor elements 52a and 52b is referred to as a series circuit. Three power terminals 56 a to 56 c extend from the upper side of the package 51. The power terminal 56a is connected to one end of the series circuit inside the package 51, and the power terminal 56b is connected to the other end of the series circuit. The power terminal 56 c is connected to the midpoint of the series circuit inside the package 51. A plurality of control terminals 57 extend from the lower side of the package 51. The control terminal 57 is a terminal connected to the gate electrodes of the semiconductor elements 52a and 52b, a terminal connected to the sense emitter, and a terminal connected to a temperature sensor built in the chip of the semiconductor elements 52a and 52b.

  Radiating plates 53a and 53b are arranged on the front surface of the package 51 (the surface facing the positive direction of the X axis). In addition, since the heat sinks 53a and 53b are covered with the insulating plate 54a as described later, the heat sinks 53a and 53b are drawn with hidden lines (broken lines) in FIG. The heat sink 53a is a part of the power terminal 56a. That is, in FIG. 3, the portion indicated by reference numeral 56 a and the portion indicated by reference numeral 53 a are connected inside the package 51. Similarly, the heat sink 53b is a part of the power terminal 56b. A similar heat radiating plate is also disposed on the rear surface of the package 51 (the surface facing the negative X-axis direction). Those heat sinks are a part of the power terminal 56c. Hereinafter, when the semiconductor elements 52a and 52b are shown without distinction, they are referred to as the semiconductor element 52, and when the heat sinks 53a and 53b and the opposite side heat sink are shown without distinction, they are referred to as the heat sink 53.

  The cooler 3 abuts on both sides of the power card 5 in the X-axis direction in the figure. As will be described later, the cooler 3 includes metal plates 13 a and 13 b on the surface facing the power card 5. In order to insulate the heat radiating plate 53 from the metal plate 13a (13b), an insulating plate 54a is attached to the front surface of the package 51 so as to cover the heat radiating plates 53a and 53b. An insulating plate 54b is also attached to the rear surface of the package 51. The insulating plate 54b insulates a heat radiating plate (not shown) disposed on the rear surface of the package 51 from the metal plate 13a (13b) of the cooler 3 facing the insulating plate 54b. Hereinafter, when any one of the insulating plates 54a and 54b is shown without distinction, it is referred to as an insulating plate 54. Similarly, when any one of the metal plates 13a and 13b is shown without distinction, the metal plate 13 is referred to. The heat of the semiconductor element 52 incorporated in the package 51 is absorbed by the cooler 3 adjacent to the power card 5 through the heat radiating plate 53 and the insulating plate 54. The insulating plate 54 may be adhered to the package 51, or may be only held between the package 51 and the cooler 3 in the stacked body 2. In some cases, grease is applied between the package 51 and the insulating plate 54. Even if the insulating plate 54 can be separated from the package 51, the insulating plate 54 is regarded as a component of the power card 5 in this specification. That is, both sides of the power card 5 including the insulating plate 54 are in contact with the cooler 3.

  Next, the structure of the cooler 3 will be described. The coolers 3a-3e have the same structure. Here, the cooler 3b will be described as a representative of the plurality of coolers 3. FIG. 4 shows an exploded perspective view of the cooler 3b. In FIG. 4, the power cards 5a and 5b located on both sides in the stacking direction of the cooler 3b are drawn with phantom lines. The cooler 3b includes a resin main body (cooler main body 30), a pair of metal plates 13a and 13b, and a pair of gaskets 12a and 12b. A flow path Ps through which a refrigerant flows is formed inside the cooler body 30. The cooler body 30 is provided with cooler openings 32a and 32b at positions facing the power cards 5 on both sides. The cooler openings 32a and 32b communicate with the flow path Ps inside the main body. Thus, although the cooler main body 30 has a complicated shape, the cooler main body 30 can be made at low cost by injection molding of resin. Moreover, since the cooler main body 30 is made of resin, it is lightweight.

  One cooler opening 32a of the cooler body 30 is closed with a metal plate 13a with the gasket 12a interposed therebetween. The other cooler opening 32b is closed by the metal plate 13b with the gasket 12b interposed therebetween. A plurality of fins 14a are provided on the surface 13a1 facing the flow path side of the metal plate 13a, and the opposite surface 13a2 faces the power card 5a. A plurality of fins 14b are provided on the surface 13b1 facing the flow path side of the metal plate 13b, and the opposite surface 13b2 faces the power card 5b. When the cooler 3b and the power card 5 are pressurized in the stacking direction, the metal plate 13a contacts the power card 5a, and the metal plate 13b contacts the power card 5b. Hereinafter, when any one of the gaskets 12a and 12b is shown without distinction, the gasket 12 is called, and when any one of the cooler openings 32a and 32b is shown without distinction, it is called a cooler opening 32.

  As described above, the plurality of power cards 5 and the plurality of coolers 3 are in a temporarily assembled state until the stacked body 2 is fixed by the bolts 11a and 11b, and the cooler opening 32 and the metal plate 13 are completely sealed. is not. The stacked body 2 of the plurality of power cards 5 and the plurality of coolers 3 is pressurized in the stacking direction by bolts 11a and 11b and nuts 15a and 15b. The pressure secures sealing of the cooler opening 32 and the metal plate 13.

  The relationship between the cooler 3 and the bolts 11a and 11b can be expressed as follows. Each of the plurality of coolers 3 includes a cooler body 30 and a metal plate 13. The cooler body 30 is provided with a flow path for the refrigerant Ps therein, and is provided with an opening (cooler opening 32) leading to the flow path Ps at a position facing the power card 5. One side of the metal plate 13 closes the cooler opening 32, and the other side is in contact with the power card 5. The stacked body 2 of the plurality of coolers 3 and the plurality of power cards 5 is bound in the stacking direction by bolts 11a and 11b. The bolts 11 a and 11 b apply a pressure in the stacking direction to the stacked body 2 to ensure a seal between the cooler opening 32 and the metal plate 13.

  A liquid refrigerant flows inside the cooler body 30. The fins 14a of the metal plate 13a and the fins 14b of the metal plate 13b are disposed in the refrigerant flow. The heat of the power card 5a is absorbed by the refrigerant through the metal plate 13a and the fins 14a provided thereon. The heat of the power card 5b is absorbed by the refrigerant through the metal plate 13b and the fins 14b provided thereon. Another cooler is also in contact with the opposite surface of the power card 5a to cool the power card 5a. Another cooler is also in contact with the opposite surface of the power card 5b to cool the power card 5b. That is, each power card is cooled on both sides. Therefore, the stacked body 2 in which the plurality of power cards 5 and the plurality of coolers 3 are alternately stacked one by one has high cooling efficiency. The cooler 3 is made of a resin whose cooler body 30 is not high in thermal conductivity, but has a high cooling performance by including a metal plate 13 in a portion where one surface is in contact with the power card 5 and the other surface is in contact with the refrigerant. Is secured.

  The cooler body 30 is horizontally long in the Y-axis direction, and cylindrical portions 35a and 35b are provided at both ends in the Y-axis direction. When expressing one of the cylindrical portions 35a and 35b without distinction, it is referred to as a cylindrical portion 35. The cylinder portion 35 extends in the stacking direction. Inside the cylindrical portion 35, through holes 34 (34a, 34b) extending in the stacking direction are formed. The through hole 34 corresponds to the first type of through hole. In the stacked body 2, the through holes 34 of the adjacent coolers 3 communicate with each other. The refrigerant supplied from the refrigerant supply pipe 91 (see FIG. 1) is distributed to all the coolers 3 through one through hole 34a. The refrigerant supplied from one through hole 34a flows in the Y-axis direction through the flow path Ps and then flows into the other through hole 34b. The refrigerant discharged from the other through-hole 34b of each cooler 3 is discharged from the refrigerant discharge pipe 92 (see FIG. 1).

  The cooler 3a located at one end of the stack 2 in the stacking direction has one surface in contact with the power card 5a, and the other surface is in contact with the front end cover 4a (see FIG. 1). The cooler 3e located at the other end of the stacked body 2 has one surface in contact with the power card 5d, but the other surface is in contact with the rear end cover 4b. A supplementary explanation will be given for the front end cover 4a and the rear end cover 4b. The front end cover 4a closes a front cooler opening (cooler opening 32a, see FIG. 4) provided in the cooler body 30 of the cooler 3a. The front end cover 4a also closes front openings of through holes 34a and 34b (see FIG. 4) provided in the cooler body 30. Further, the front end cover 4a is provided with a refrigerant supply pipe 91 and a refrigerant discharge pipe 92. The rear end cover 4b closes the rear cooler opening (cooler opening 32b, see FIG. 4) provided in the cooler body 30 of the cooler 3e. The rear end cover 4b also closes the rear openings of the through holes 34a and 34b (see FIG. 4) provided in the cooler body 30.

  Details of the means for fixing the laminate 2 with the bolts 11a and 11b will be described. As shown in FIG. 4, the cooler main body 30 is provided with through holes 37 a and 37 b at both ends in the Y-axis direction. The through holes 37a and 37b are located at ends of the through holes 34a and 34b, respectively. The through holes 37a and 37b correspond to the second type of through holes. In the laminate 2, the through holes 37 a of the adjacent coolers 3 communicate with each other. As shown in FIG. 1, the fixing plate 7a is provided with through holes 9a and 9b at both ends in the Y-axis direction. The through holes 9a and 9b are located at ends of the refrigerant supply pipe 91 and the refrigerant discharge pipe 92, respectively. As shown in FIG. 2, the fixing plate 7b is provided with through holes 9c and 9d at both ends in the Y-axis direction. Although not apparent from FIG. 1, the front end cover 4a and the rear end cover 4b are provided with through holes at both ends in the Y-axis direction. The through hole 9a of the fixed plate 7a, one through hole of the front end cover 4a, the through hole 37a of the cooler 3, the one through hole of the rear end cover 4b, and the through hole 9c of the fixed plate 7b communicate with each other. doing. Bolts 11a are inserted into these through holes and fastened with nuts 15a. The through hole 9b of the fixed plate 7a, the other through hole of the front end cover 4a, the through hole 37b of the cooler 3, the other through hole of the rear end cover 4b, and the through hole 9d of the fixed plate 7b communicate with each other. doing. Bolts 11b are inserted into these through holes and fastened with nuts 15b. Thereby, the laminated body 2 is pressurized by the volt | bolts 11a and 11b and nut 15a, 15b in the lamination direction. According to the present embodiment, the power converter 100 can be reduced in size and weight as compared with the configuration in which the laminated body is pressed by the leaf spring.

  The relationship between the cooler 3 and the bolts 11a and 11b can also be expressed as follows. Each of the plurality of coolers 3 includes a cooler body 30 and a metal plate 13. The cooler body 30 is provided with a flow path for the refrigerant Ps therein, and is provided with an opening (cooler opening 32) leading to the flow path Ps at a position facing the power card 5. One side of the metal plate 13 closes the cooler opening 32, and the other side is in contact with the power card 5. The stacked body 2 of the plurality of coolers 3 and the plurality of power cards 5 is bound in the stacking direction by bolts 11a and 11b. The bolts 11 a and 11 b apply a pressure in the stacking direction to the stacked body 2 to ensure a seal between the cooler opening 32 and the metal plate 13.

(Second embodiment)
As shown in FIG. 5, the second embodiment differs from the first embodiment in the positions of the through holes provided in the fixing plates 7a and 7b. The positions of the through holes 9a and 9b provided in the fixing plate 7a are closer to the center than the refrigerant supply pipe 91 and the refrigerant discharge pipe 92, respectively. The positions of the through holes of the front end cover 4a, the cooler 3, the rear end cover 4b, and the fixing plate 7b are also close to the center according to the positions of the through holes 9a and 9b. In particular, the through holes of the cooler 3 are not shown, but are provided at both ends of the metal plates 13a and 13b in the Y-axis direction and face the flow path Ps (see FIG. 4). As in the first embodiment, bolts 11a and 11b are inserted into these through holes and fastened with nuts 15a and 15b. Gaskets are sandwiched between the through holes provided in the metal plates 13a and 13b and the bolts 11a and 11b, respectively, and are sealed. Thereby, it can prevent that a refrigerant | coolant leaks outside from the flow path Ps. 4 and 5, the bolt 11 a passes between the cylindrical portion 35 a and the power card 5, and the bolt 11 b passes between the cylindrical portion 35 b and the power card 5. . In the second embodiment, the same effects as in the first embodiment can be obtained.

  In the second embodiment, the bolt 11 (11a, 11b) penetrates the metal plate 13 (13a, 13b). Sealing between the metal plate 13 and the cooler opening 32 is ensured by the pressure applied in the stacking direction by the bolt 11. By adopting a structure in which the bolt 11 penetrates the metal plate 13, the metal plate 13 abuts uniformly on the edge of the cooler opening 32 of the cooler body 30, and the sealing between the cooler opening 32 and the metal plate 13 is performed. The property is further improved.

  When the bolt 11 penetrates the metal plate 13, the bolt 11 and the metal plate 13 are in contact with each other, and the two are preferably electrically connected. Such a structure is suitable when the cooler body 30 is made of an insulating resin. As described above, the heat dissipation plate 53 and the like of the power card 5 are electrically connected to the semiconductor element. Therefore, the heat sink 53 and the like, the metal plate 13, and the insulating plate 54 sandwiched between them constitute a capacitor. When the cooler body 30 is made of an insulator, the metal plate 13 corresponding to one electrode of the capacitor is in an electrically floating state. When the bolt 11 and the metal plate 13 are in contact with each other, and the bolt 11 is in electrical contact with a metal housing (not shown) of the power converter, the metal plate 13 is electrically connected to the housing (that is, grounding ground). To do. Since one electrode of the capacitor described above is electrically connected to the ground, high frequency noise generated by the semiconductor element inside the power card 5 can be guided to the ground.

  When the through holes into which the same bolts are inserted are considered as one set of through holes, in each of the above embodiments, the power converter 100 has two sets of through holes. In the modification, the power converter 100 may have only one set of through holes, or may have three or more sets of through holes.

  The configuration in which the laminated body 2 is pressurized with the bolts 11a and 11b and the nuts 15a and 15b is advantageous in that the pressure applied to the laminated body 2 can be adjusted by the tightening degree of the nuts 15a and 15b.

  The front end cover 4a and the fixed plate 7a may be configured integrally, and the rear end cover 4b and the fixed plate 7b may be configured integrally. The bolt 11a and the nut 15a, and the bolt 11b and the nut 15b correspond to an example of a binding rod.

  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: Laminated body 3, 3a-3e: Cooler 4a: Front end cover 4b: Rear end cover 5, 5a-5d: Power card 7a, 7b: Fixing plates 9a-9d, 34a, 34b, 37a, 37b: Through hole 11a 11b: bolts 12a, 12b: gaskets 13a, 13b: metal plates 13a1, 13a2, 13b1, 13b2: surfaces 14a, 14b: fins 15a, 15b: nuts 30: cooler bodies 32a, 32b: cooler openings 35a, 35b: Cylindrical part 51: Packages 52a, 52b: Semiconductor elements 53a, 53b: Heat radiation plates 54a, 54b: Insulating plates 56a-56c: Power terminal 57: Control terminal 91: Refrigerant supply pipe 92: Refrigerant discharge pipe 100: Power converter Ps: Flow path

Claims (1)

A plurality of power cards each containing a semiconductor element;
A plurality of coolers stacked with the plurality of power cards, each in contact with each of the plurality of power cards;
Two plates disposed at both ends in a stacking direction of a stacked body in which the plurality of power cards and the plurality of coolers are stacked;
With
The laminated body and the two plates are provided with through holes communicating in the laminating direction,
A binding rod is inserted into each of the through holes of the laminate and the two plates, and the binding rod is fastened to the plates on both sides in the stacking direction,
The power converter, wherein the binding rod pressurizes the laminated body in the laminating direction.

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