JP2018042309A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that prevents a short circuit in a positive electrode bus bar and a negative electrode bus bar disposed close and opposite to each other.SOLUTION: A positive electrode bus bar 30 and a negative electrode bus bar 40 respectively connect positive electrode terminals 25a and negative electrode terminals 25b of a plurality of semiconductor modules 8 to a capacitor element 61. An insulation plate 50 is sandwiched between the positive electrode bus bar 30 and the negative electrode bus bar 40. A protective cover 70 is disposed opposite the insulation plate 50 of the negative electrode bus bar 40. The negative electrode bus bar 40 has a third hole 45 through which the positive electrode terminal 25a and a first branch part 33 pass. The insulation plate 50 has a cylindrical part 53 through which the positive electrode terminal 25a and the first branch part 33 pass, and the cylindrical part 53 passes through the third hole 45 of the negative electrode bus bar 40. The protective cover 70 has a fourth hole 73 through which the positive electrode terminal 25a and the first branch part 33 pass. The leading end of the cylindrical part 53 of the insulation plate 50 abuts on an edge of the fourth hole 73. The positive electrode terminal 25a and the first branch part 33 are welded at a point projecting from the cylindrical part 53.SELECTED DRAWING: Figure 5

Description

  The technology disclosed in this specification relates to a power conversion device. In particular, the present invention relates to a power conversion device having a stacked unit in which a plurality of coolers are arranged in parallel and a semiconductor module is sandwiched between adjacent coolers.

  For example, Patent Document 1 discloses a power conversion device including the above-described laminated unit. Each semiconductor module accommodates one to several switching elements. A plurality of terminals (for example, a first terminal and a second terminal) that are electrically connected to the switching element are extended from the main body of the semiconductor module. The terminals of the plurality of semiconductor modules are arranged in one example in the stacking direction of the semiconductor module and the cooler. The first terminal group and the second terminal group are arranged in two rows. Next to the multilayer unit, a capacitor unit containing a capacitor element is located. The first terminal of each semiconductor module and one electrode of the capacitor element are connected by a first bus bar, and the second terminal of each semiconductor module and the other electrode of the capacitor element are connected by a second bus bar. Each of the first bus bar and the second bus bar has a plate-like base portion, and a plurality of branch portions joined to the respective terminals extend from the base portion. Usually, a terminal and a branch part are joined by welding. The plate-like base portion of the first bus bar and the plate-like base portion of the second bus bar are disposed in close proximity to each other. By arranging the two bases close to each other and facing each other, the bus bar inductance is reduced.

JP2015-015787A

  Each branch part of the first bus bar and each first terminal are joined by welding, and each branch part of the second bus bar and each second terminal are joined by welding. Since the first terminal group and the second terminal group are arranged in two rows, it is difficult to use a protective sheet or the like that isolates the welded part from the surroundings during welding. On the other hand, the base portions of the first bus bar and the second bus bar are arranged close to each other. Therefore, there is a possibility that the two bus bars are short-circuited by the welding powder scattered during welding. A structure that prevents a short circuit due to welding powder is desired.

  The power converter disclosed in the present specification includes a laminated unit, a capacitor unit, a plate-like first bus bar, a plate-like second bus bar, an insulating plate, and a protective cover. In the stacked unit, a plurality of coolers are arranged side by side, and a semiconductor module containing a switching element is sandwiched between adjacent coolers. The capacitor unit is arranged next to the multilayer unit. A capacitor element is accommodated in the capacitor unit, and a filler is filled around the capacitor element. The first bus bar is joined to a first terminal extending from each side surface of the plurality of semiconductor modules, and is connected to one electrode of the capacitor element. The second bus bar is disposed to face the plate-like first bus bar. The second bus bar is joined to the second terminal extending from the side surface of each semiconductor module and is connected to the other electrode of the capacitor element. The insulating plate is sandwiched between the first bus bar and the second bus bar, and insulates the first bus bar from the second bus bar.

  The first terminals of the plurality of semiconductor modules are arranged in a line along the stacking direction of the cooler and the semiconductor module, and the plurality of second terminals are arranged in a line parallel to the line of the first terminals. The plate-like first bus bar has a plurality of first holes through which each of the plurality of first terminals passes, and a first branch portion joined to each first terminal from the edge of each first hole. Is extended. The plate-like second bus bar is located on the side opposite to the stacked unit of the first bus bar, has a plurality of second holes through which each of the plurality of second terminals passes, and each second hole. A second branch portion joined to each of the second terminals extends from the edge. The second bus bar includes a plurality of third holes through which the first terminals and the first branches pass, respectively. The insulating plate includes a plurality of cylindrical portions through which the respective first terminals and the first branch portions pass, and the respective cylindrical portions pass through the respective third holes of the second bus bar. The protective cover overlaps with the second bus bar on the opposite side of the insulating plate, and is provided with a plurality of fourth holes through which the first terminals and the first branch portions pass, and is insulated at the edges of the respective fourth holes. The tips of the respective cylindrical portions of the plate are in contact with each other. Each 1st terminal and the 1st branch part are welded in the location protruded from the cylinder part. A part of the protective cover is embedded in the filler of the capacitor unit.

  According to the power converter described above, first, the insulating plate disposed between the first bus bar and the second bus bar prevents a short circuit between the first bus bar and the second bus bar. In particular, the first branch portion and the first terminal of the first bus bar pass through the third hole of the second bus bar, and the first terminal and the first branch portion are surrounded by the cylindrical portion of the insulating plate, The first branch portion is prevented from contacting the second bus bar. A protective cover is overlaid on the second bus bar. The protective cover is provided with a plurality of fourth holes. Each 4th hole passes each 1st terminal and a 1st branch part. The tip of each cylindrical portion of the insulating plate is in contact with the edge of each fourth hole. And the 1st terminal and the 1st branch part are welded in the location projected from the cylinder part. Even if the welding powder falls into the cylindrical portion, the inner side of the cylindrical portion is isolated from the second bus bar, so that no short circuit occurs. Moreover, since the outer side of a cylinder part is covered with a protective cover, the welding powder which fell to the outer side of a cylinder part does not adhere to a 2nd bus bar. Thus, a short circuit between the first bus bar and the second bus bar is prevented. The protective cover is firmly fixed because a part of the protective cover is embedded in the filler of the capacitor unit.

  Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a block diagram of the electric power system of the electric vehicle containing the power converter device of an Example. It is a perspective view of the assembly of a lamination unit, a bus bar, and a capacitor unit. It is a disassembled perspective view of a laminated unit, a bus bar, and a capacitor unit. It is sectional drawing along the IV-IV line of FIG. It is sectional drawing along the VV line of FIG.

  A power converter according to an embodiment will be described with reference to the drawings. The power conversion apparatus according to the embodiment is a device that is mounted on an electric vehicle and converts battery power into driving power for a travel motor. FIG. 1 shows a block diagram of a power system of an electric vehicle 100 including the power conversion device 2. The electric vehicle 100 includes two traveling motors 83a and 83b. Therefore, the power conversion device 2 includes two sets of inverter circuits 13a and 13b. The outputs of the two motors 83a and 83b are combined / distributed by the gear box 85 and transmitted to the axle 86 (that is, drive wheels).

  The power conversion device 2 is connected to a battery 81 via a system main relay 82. The power conversion device 2 includes a voltage converter circuit 12 that boosts the voltage of the battery 81, and two sets of inverter circuits 13a and 13b that convert the boosted DC power into AC.

  The voltage converter circuit 12 boosts the voltage applied to the battery-side terminal and outputs the boosted voltage to the inverter-side terminal, and steps down the voltage applied to the inverter-side terminal and outputs the voltage to the battery-side terminal. This is a bidirectional DC-DC converter capable of performing both step-down operations. For convenience of explanation, a terminal on the battery side (low voltage side) is hereinafter referred to as an input end 18, and a terminal on the inverter side (high voltage side) is referred to as an output end 19. Further, the positive electrode and the negative electrode of the input end 18 are referred to as an input positive electrode end 18a and an input negative electrode end 18b, respectively. The positive electrode and the negative electrode of the output end 19 are referred to as an output positive electrode end 19a and an output negative electrode end 19b, respectively. The notations "input terminal 18" and "output terminal 19" are for convenience of explanation, and as described above, the voltage converter circuit 12 is a bidirectional DC-DC converter. In some cases, power flows from 19 to the input terminal 18.

  The voltage converter circuit 12 includes a series circuit of two switching elements 9a and 9b, a reactor 7, a filter capacitor 5, and a diode connected in antiparallel to each switching element. Reactor 7 has one end connected to input positive end 18a and the other end connected to the midpoint of the series circuit. The filter capacitor 5 is connected between the input positive terminal 18a and the input negative terminal 18b. The input negative electrode end 18b is directly connected to the output negative electrode end 19b. The switching element 9b is mainly involved in the step-up operation, and the switching element 9a is mainly involved in the step-down operation. Since the voltage converter circuit 12 of FIG. 1 is well known, detailed description thereof is omitted. Note that a circuit within a broken-line rectangle indicated by reference numeral 8a corresponds to a semiconductor module 8a described later. Reference numerals 25a and 25b denote terminals extending from the semiconductor module 8a. The code | symbol 25a has shown the terminal (positive electrode terminal 25a) electrically connected with the high potential side of the series circuit of switching element 9a, 9b. Reference numeral 25b represents a terminal (negative electrode terminal 25b) that is electrically connected to the low potential side of the series circuit of the switching elements 9a and 9b. As will be described next, the notation of the positive terminal 25a and the negative terminal 25b is also used in other semiconductor modules.

  The inverter circuit 13a has a configuration in which three sets of series circuits of two switching elements are connected in parallel. Switching elements 9c and 9d, switching elements 9e and 9f, and switching elements 9g and 9h constitute a series circuit. A diode is connected in antiparallel to each switching element. The terminals on the high potential side (positive terminal 25a) of the three sets of series circuits are connected to the output positive terminal 19a of the voltage converter circuit 12, and the terminals on the low potential side (negative terminal 25b) of the three sets of series circuits are voltage. The output negative terminal 19b of the converter circuit 12 is connected. Three-phase alternating current (U-phase, V-phase, W-phase) is output from the midpoint of the three sets of series circuits. Each of the three sets of series circuits corresponds to semiconductor modules 8b, 8c, and 8d described later.

  Since the configuration of the inverter circuit 13b is the same as that of the inverter circuit 13a, a specific circuit is not shown in FIG. Similarly to the inverter circuit 13a, the inverter circuit 13b has a configuration in which three sets of series circuits of switching elements are connected in parallel. The terminals on the high potential side of the three sets of series circuits are connected to the output positive end 19a of the voltage converter circuit 12, and the terminals on the low potential side of the three sets of series circuits are connected to the output negative end 19b of the voltage converter circuit 12. Has been. Hardware corresponding to each series circuit is referred to as semiconductor modules 8e, 8f, and 8g.

  A smoothing capacitor 6 is connected in parallel to the input terminals of the inverter circuits 13a and 13b. In other words, the smoothing capacitor 6 is connected in parallel to the output end 19 of the voltage converter circuit 12. Smoothing capacitor 6 removes pulsation of the output current of voltage converter circuit 12.

  The switching elements 9a-9h are transistors and are typically IGBTs (Insulated Gate Bipolar Transistors), but may be other transistors such as MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). Moreover, the switching element here is used for power conversion, and may be called a power semiconductor element.

  In FIG. 1, each of broken lines 8a-8g corresponds to a semiconductor module. The power conversion device 2 includes seven sets of series circuits of two switching elements. As hardware, two switching elements constituting a series circuit and a diode connected in antiparallel to each switching element are accommodated in one package. Hereinafter, when any one of the semiconductor modules 8a to 8g is shown without distinction, it is referred to as a semiconductor module 8.

  The terminals on the high potential side (positive terminal 25a) of the seven semiconductor modules (seven sets of series circuits) are connected to the positive electrode of the smoothing capacitor 6, and the terminal on the low potential side (negative terminal 25b) is the negative electrode of the smoothing capacitor 6. Connected to the electrode. In FIG. 1, the conductive path within the broken line indicated by reference numeral 30 corresponds to a bus bar (positive bus bar) that connects the positive terminals 25 a of the plurality of semiconductor modules 8 and the positive electrodes of the smoothing capacitor 6 to each other. A conductive path in a broken line indicated by reference numeral 40 corresponds to a bus bar (negative electrode bus bar) that connects the plurality of negative electrode terminals 25b and the negative electrode of the smoothing capacitor 6 to each other. Next, the structure of the plurality of semiconductor modules 8, the positive electrode bus bar 30, and the negative electrode bus bar 40 will be described.

  FIG. 2 shows a perspective view of the hardware of the power conversion device 2. 2, illustration of the housing and some components of the power converter device 2 is omitted. The plurality of semiconductor modules 8 (8a-8g) together with the plurality of coolers 22 constitute a stacked unit 20. Since all the semiconductor modules 8a-8g have the same shape, in FIG. 2 and FIG. 3 to be described later, only the leftmost semiconductor module is represented by reference numeral 8, and the other semiconductor modules are omitted. In FIG. 2 and FIG. 3 to be described later, only the leftmost two coolers are denoted by reference numeral 22, and the other coolers are not denoted by reference numerals.

  FIG. 2 is a perspective view of the power conversion apparatus 2, but only the assembly of the laminated unit 20, the positive electrode bus bar 30, the negative electrode bus bar 40, and the capacitor unit 60 is illustrated, and the other components are not shown. The stacked unit 20 is a device in which a plurality of card-type coolers 22 are arranged in parallel and a card-type semiconductor module 8 is sandwiched between adjacent coolers 22. The card type semiconductor module 8 is laminated with its wide surface facing the cooler 22. Three terminals (a positive terminal 25a, a negative terminal 25b, and a midpoint terminal 25c) extend from one side surface 80a of each semiconductor module 8. 2 and FIG. 3 to be described later, only the terminals of the semiconductor module 8 located at the left end of the stacked unit 20 are denoted by reference numerals 25a, 25b, and 25c, and the remaining semiconductor modules 8 are omitted from the reference numerals indicating the terminals.

  As described above, the positive electrode terminal 25a and the negative electrode terminal 25b are a high potential side terminal and a low potential side terminal of the series circuit accommodated in the semiconductor module 8. The midpoint terminal 25c is a terminal that is electrically connected to the midpoint of the series circuit. In other words, all the three terminals 25 a to 25 c are electrically connected to the switching element inside the semiconductor module 8. The three terminals 25 a to 25 c extend in the positive direction of the Z axis in the drawing from one side surface 80 a that intersects the wide surface of the semiconductor module 8. A plurality of control terminals extend in the Z-axis negative direction from the side surface opposite to the one side surface 80a. The control terminal is a gate terminal that is electrically connected to a gate electrode of a switching element incorporated in the semiconductor module 8, a signal terminal that is electrically connected to a temperature sensor or a current sensor incorporated in the semiconductor module 8, and the like. .

  Hereinafter, for convenience of explanation, the stacking direction of the cooler 22 and the semiconductor module 8 in the stacking unit 20 is simply referred to as “stacking direction”. The X direction in the figure corresponds to the stacking direction.

  The rightmost cooler 22 in the drawing is provided with a refrigerant supply port 28 and a refrigerant discharge port 29. Adjacent coolers 22 are connected by two connecting pipes. One connecting pipe is positioned so as to overlap the refrigerant supply port 28 when viewed from the stacking direction. The other connecting pipe is positioned so as to overlap with the refrigerant outlet 29 when viewed from the stacking direction. A refrigerant circulation device (not shown) is connected to the refrigerant supply port 28 and the refrigerant discharge port 29. The refrigerant supplied from the refrigerant supply port 28 is distributed to all the coolers 22 through one connecting pipe. The refrigerant absorbs heat from the adjacent semiconductor module 8 while passing through the cooler 22. The refrigerant that has absorbed heat is discharged from the stacked unit 20 through the other connecting pipe and the refrigerant discharge port 29. Since each semiconductor module 8 is cooled from both sides, the stacked unit 20 has high cooling performance.

  Each of the three terminals 25a-25c of each semiconductor module 8 is flat. The positive terminals 25a of the plurality of semiconductor modules 8 are arranged in a line in the stacking direction so as to face the flat surface of the positive terminals 25a of the adjacent semiconductor modules 8. The negative terminals 25b of the plurality of semiconductor modules 8 are also arranged in a line in the stacking direction so as to face the flat surface of the negative terminals 25b of the adjacent semiconductor modules 8. The same applies to the midpoint terminals 25c of the plurality of semiconductor modules 8. The positive terminal 25a, the negative terminal 25b, and the midpoint terminal 25c of the plurality of semiconductor modules 8 are arranged in three rows.

  FIG. 3 shows an exploded perspective view of an assembly of the positive electrode bus bar 30, the negative electrode bus bar 40, the multilayer unit 20, and the capacitor unit 60 (capacitor element 61). Note that two capacitor elements 61 are accommodated in the capacitor unit 60 of FIG. In FIG. 3, the case of the capacitor unit 60 is omitted, and the internal capacitor element 61 is drawn. As will be described in detail later, the periphery of the capacitor element 61 is filled with a filler in the case of the capacitor unit 60. The capacitor element 61 corresponds to the smoothing capacitor 6 in FIG.

  The positive electrode terminals 25 a of the plurality of semiconductor modules 8 and the positive electrode 61 a of the capacitor element 61 are connected by the positive electrode bus bar 30, and the negative electrode terminals 25 b and the negative electrode 61 b of the capacitor element 61 are connected by the negative electrode bus bar 40.

  The positive electrode bus bar 30 includes a plate-like electrode portion 39, a plate-like base portion 31, and a plurality of branch portions 33. The electrode part 39 is connected to the positive electrode 61 a of the capacitor element 61. A plurality of first holes 32 are provided in the base portion 31 of the positive electrode bus bar 30, and branch portions 33 extend in the Z direction from the edges of the first holes 32. The positive terminal 25a of each semiconductor module 8 passes through each first hole 32, and the positive terminal 25a and the branch portion 33 are joined.

  The negative electrode bus bar 40 includes a plate-like electrode portion 49, a plate-like base portion 41, and a plurality of branch portions 43. The electrode portion 49 is connected to the negative electrode 61 b of the capacitor element 61. A plurality of second holes 42 are provided in the base portion 41 of the negative electrode bus bar 40, and branch portions 43 extend in the Z direction from the edges of the second holes 42. The negative terminal 25b of each semiconductor module 8 passes through each second hole 42, and the negative terminal 25b and the branch portion 43 are joined.

  The negative electrode bus bar 40 is located on the opposite side of the positive electrode bus bar 30 from the stacked unit 20. A plurality of third holes 45 are provided in the negative electrode bus bar 40, and the positive terminal 25 a of the semiconductor module 8 passes through each third hole 45. The plate-like base 31 of the positive electrode bus bar 30 and the plate-like base 41 of the negative electrode bus bar 40 are close to each other.

  An insulating plate 50 is sandwiched between the positive electrode bus bar 30 and the negative electrode bus bar 40. The insulating plate 50 insulates between the positive electrode bus bar 30 and the negative electrode bus bar 40. The insulating plate 50 is provided with a plurality of cylindrical portions 53 and a plurality of fifth holes 54. Ribs 51 extending in the Y direction are provided on both sides of the insulating plate 50 in the stacking direction (X direction), and protrusions 52 extend from the ribs 51. The base portion 41 of the negative electrode bus bar 40 is accommodated between the pair of ribs 51.

  A protective cover 70 is disposed so as to overlap the negative electrode bus bar 40 on the opposite side of the insulating plate 50. The protective cover 70 is provided with a plurality of fourth holes 73 through which the positive terminal 25a and the branch portion 33 of the positive bus bar 30 pass. The protective cover 70 has an insulating part 72 made of an insulating material and a metal part 71 made of copper. A fourth hole 73 is provided in the metal part 71. The protective cover 70 is provided with a through hole 74 at a location corresponding to the protrusion 52 of the insulating plate 50. When the insulating plate 50, the negative electrode bus bar 40, and the protective cover 70 are overlapped, the protrusion 52 of the insulating plate 50 is fitted into the through hole 74 of the protective cover 70, and the insulating plate 50 and the protective cover 70 are firmly connected. In FIG. 3, a portion indicated by reference numeral 72 a indicates a portion of the protective cover 70 that is embedded in the capacitor unit 60. This point will be described later.

  The relationship among the positive electrode bus bar 30, the negative electrode bus bar 40, the insulating plate 50, and the protective cover 70 will be described with reference to FIG. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2, and is a cross section crossing the positive electrode terminal 25a. 4 shows only a partial cross section of the assembly of the laminated unit 20, the positive electrode bus bar 30, the negative electrode bus bar 40, the insulating plate 50, and the protective cover 70.

  The positive electrode bus bar 30, the negative electrode bus bar 40, the insulating plate 50, and the protective cover 70 are overlapped. As described above, the insulating plate 50 is sandwiched between the positive electrode bus bar 30 and the negative electrode bus bar 40 and insulates between the two. Among the positive electrode bus bar 30, the negative electrode bus bar 40, the insulating plate 50, and the protective cover 70, the positive electrode bus bar 30 is positioned closest to the semiconductor module 8. An insulating plate 50 overlaps the positive electrode bus bar 30, a negative electrode bus bar 40 overlaps thereon, and a protective cover 70 overlaps thereon. The branch portion 33 of the positive electrode bus bar 30 is welded to the semiconductor module side of the base portion 31 of the positive electrode bus bar 30. The branch portion 33 extends from the edge of the first hole 32 of the base portion 31.

  The first hole 32 provided in the positive electrode bus bar 30, the cylindrical portion 53 provided in the insulating plate 50, the third hole 45 provided in the negative electrode bus bar 40, and the fourth hole 73 provided in the protective cover 70 are The positive electrode bus bar 30 and the negative electrode bus bar 40 overlap when viewed from the stacking direction (Z direction in the figure). The positive electrode terminal 25a of the semiconductor module 8 and the branch portion 33 of the positive electrode bus bar 30 pass through these holes. The positive electrode terminal 25 a and the branch portion 33 of the positive electrode bus bar 30 pass through the inside of the cylindrical portion 53 of the insulating plate 50, and the cylindrical portion 53 itself passes through the third hole 45 of the negative electrode bus bar 40. The distal end of the cylindrical portion 53 is in contact with the edge of the fourth hole 73 of the protective cover 70.

  With the above structure, the negative electrode bus bar 40 is isolated from the branch portion 33 of the positive electrode bus bar 30 and the positive electrode terminal 25a in the vicinity of the positive electrode terminal 25a. First, the cylindrical portion 53 of the insulating plate 50 passes through the third hole 45 of the negative electrode bus bar 40, and the positive electrode terminal 25a and the branch portion 33 pass through the inside of the cylindrical portion 53, so that the periphery of the third hole 45 is the positive electrode terminal 25a. And isolated from the branch portion 33. Further, the tip of the cylindrical portion 53 abuts against the edge of the fourth hole 73 of the protective cover 70, so that the space Sp facing the surface of the base 41 of the negative electrode bus bar 40 is covered with the metal portion 71 of the protective cover 70. Is isolated from the positive electrode terminal 25 a and the branch portion 33. The positive electrode terminal 25 a and the branch portion 33 of the positive electrode bus bar 30 are welded at portions protruding from the cylindrical portion 53 and the fourth hole 73. An arrow A in FIG. 4 schematically represents a laser beam for welding. That is, the location indicated by the arrow A is a location where the positive electrode terminal 25 a and the branch portion 33 are welded. During welding, welding powder may scatter from the positive electrode terminal 25a or the branch portion 33. In FIG. 4, the dotted line indicated by the symbol Q schematically represents the welding powder. As described above, since the negative electrode bus bar 40 is isolated from the positive electrode terminal 25a and the branch portion 33 around the positive electrode terminal 25a, the welding powder does not adhere to the negative electrode bus bar 40. Therefore, the negative electrode bus bar 40 and the positive electrode bus bar 30 are prevented from being short-circuited via the welding powder. The fourth hole 73 of the protective cover 70 is provided in the metal part 71, and the welding powder adheres to the metal part 71. Since the welding powder adheres to the metal part 71, it is prevented from being scattered to other parts.

  FIG. 5 shows a cross section taken along line VV in FIG. FIG. 5 shows a cross section traversing the cylindrical portion 53. Also in FIG. 5, the cylindrical portion 53 of the insulating plate 50 separates the edge of the third hole 45 of the negative electrode bus bar 40 from the positive electrode terminal 25a and the branch portion 33, and a protective cover is provided around the positive electrode terminal 25a. It is understood that 70 covers the negative electrode bus bar 40.

  The internal structure of the capacitor unit 60 will be described with reference to FIG. The capacitor element 61 is accommodated in the case 68 of the capacitor unit 60. The case 68 is made of an insulating resin. A filler 69 is filled around the capacitor element 61 inside the case 68. The filler 69 is, for example, a silicone-containing potting material. Inside the case 68, the electrode part 39 of the positive electrode bus bar 30 is connected to the positive electrode 61a of the capacitor element 61, and the electrode part 49 of the negative electrode bus bar 40 is connected to the negative electrode 61b of the capacitor element 61.

  A part 72 a of the protective cover 70 enters the capacitor unit 60 and is embedded in the filler 69. Since a part 72 a of the protective cover 70 is embedded in the filler 69, the protective cover 70 is firmly fixed to the capacitor unit 60.

  The power conversion device 2 includes the positive electrode bus bar 30, the negative electrode bus bar 40, the insulating plate 50, and the protective cover 70, thereby preventing a short circuit between the positive electrode bus bar 30 and the negative electrode bus bar 40. In particular, a short circuit caused by welding powder when welding the branch portion 33 of the positive electrode bus bar 30 and the positive electrode terminal 25a of the semiconductor module 8 is prevented.

  Points to be noted regarding the technology described in the embodiments will be described. The positive electrode bus bar 30 of the embodiment corresponds to an example of a first bus bar in the claims, and the negative electrode bus bar 40 corresponds to an example of a second bus bar of the embodiment. The positive electrode terminal 25a of the embodiment corresponds to an example of a first terminal in the claims, and the negative electrode terminal 25b of the embodiment corresponds to an example of a second terminal in the claims. The branch portion 33 of the positive electrode bus bar 30 of the embodiment corresponds to an example of “first branch portion” in the claims, and the branch portion 43 of the negative electrode bus bar 40 corresponds to an example of “second branch portion” of the claims. The “positive electrode” and “negative electrode” in the embodiments may be reversed.

  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: Power converter 5: Filter capacitor 6: Smoothing capacitor 7: Reactor 8, 8a-8g: Semiconductor module 9a-9h: Switching element 12: Voltage converter circuit 13a, 13b: Inverter circuit 20: Multilayer unit 22: Cooler 25a : Positive terminal 25b: Negative terminal 25c: Midpoint terminal 30: Positive bus bar 31, 41: Base part 32: First hole 33, 43: Branch part 39, 49: Electrode part 40: Negative electrode bus bar 42: Second hole 45: Second 3 hole 50: insulating plate 51: rib 52: projection 53: tube portion 54: fifth hole 60: capacitor unit 61: capacitor element 61a: positive electrode 61b: negative electrode 68: case 69: filler 70: protective cover 71: Metal part 72: Insulating part 81: Battery 82: System main relay 83a, 83b: Motor 85: Gear box 100: Electricity Dosha

Claims (1)

A plurality of coolers are arranged side by side, and a laminated unit in which a semiconductor module containing a switching element is sandwiched between the adjacent coolers, and
A capacitor unit which is arranged next to the multilayer unit and contains a capacitor element and is filled with a filler around the capacitor element;
A plate-like first bus bar that is joined to a first terminal extending from each side surface of the plurality of semiconductor modules and connected to one electrode of the capacitor element;
A plate-like plate disposed opposite to the plate-like first bus bar, joined to the second terminal extending from the side surface of each semiconductor module, and connected to the other electrode of the capacitor element No. 2 bus bar,
An insulating plate sandwiched between the first bus bar and the second bus bar;
A protective cover;
With
The first terminals of the plurality of semiconductor modules are arranged in a line along the stacking direction of the cooler and the semiconductor module, and the plurality of second terminals are arranged in a line parallel to the line of the first terminals. Lined up
The first bus bar has a plurality of first holes through which each of the plurality of first terminals passes, and a first branch portion joined to each first terminal from an edge of each first hole. Is extended,
The second bus bar is located on the opposite side of the first bus bar from the stacked unit, has a plurality of second holes through which the plurality of second terminals pass, and each second bus bar. A second branch portion joined to each of the second terminals extends from an edge of the hole, and includes a plurality of third holes through which each of the first terminals and each of the first branch portions pass.
The insulating plate includes a plurality of cylindrical portions through which the first terminals and the first branch portions pass, and the cylindrical portions pass through the third holes of the second bus bar. And
The protective cover overlaps the second bus bar on the opposite side of the insulating plate, and is provided with a plurality of fourth holes through which the first terminals and the first branch portions pass, respectively. The tip of each cylindrical portion of the insulating plate is in contact with the edge of the hole,
Each said 1st terminal and said 1st branch part are welded in the location protruded from the said cylinder part,
A power converter, wherein a part of the protective cover is embedded in the filler of the capacitor unit.

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