JP2018042311A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both a reduction in the inductance of a positive electrode bus bar and a negative electrode bus bar and a reduction in internal stress applied on a terminal of a semiconductor module connected to each bus bar.SOLUTION: A positive electrode bus bar 30 comprises: a first flat plate part 31 extending between a positive electrode terminal 25a and a negative electrode terminal 25b along a side face 80a of a semiconductor module 8 from a smoothing capacitor 6; a second flat plate part 32 bent from an edge of the first flat plate part 31 between the positive electrode terminal 25a and the negative electrode terminal 25b and extending in the direction in which the positive electrode terminal 25a extends; and a plurality of branch parts 33 extending to the leading end of each positive electrode terminal 25a from the second flat plate part 32. A negative electrode bus bar 40 also has a similar shape. The first flat plate part 31 and second flat plate part 32 of the positive electrode bus bar 30 are close and opposite to the first flat plate part 41 and second flat plate part 42, respectively, of the negative electrode bus bar 40. The branch part 31 is connected to the leading end of the positive electrode terminal 25a and the branch part 41 is connected to the leading end of the negative electrode terminal 25b.SELECTED DRAWING: Figure 2

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 Documents 1-3 disclose a power conversion device including the above-described laminated unit. Each semiconductor module accommodates one to several switching elements. A plurality of terminals (a positive terminal and a negative terminal) that are electrically connected to the switching element extend 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 positive electrode terminal group and the negative electrode terminal group are arranged in two rows. A capacitor is disposed next to the laminated unit. The positive electrode terminal of each semiconductor module and one electrode of the capacitor are connected by a positive electrode bus bar, and the negative electrode terminal of each semiconductor module and the other electrode of the capacitor are connected by a negative electrode bus bar. Each of the positive electrode bus bar and the negative electrode bus bar has a plate-like base portion (flat plate portion), and a plurality of branch portions joined to the respective terminals extend from the flat plate portion. Usually, a terminal and a branch part are joined by welding. The flat plate portion of the positive electrode bus bar and the flat plate portion of the negative electrode bus bar are disposed close to and opposed to each other. The inductance of the bus bar is reduced by arranging the two flat plate portions in close proximity to each other.

JP 2013-090408 A JP 2014-110400 A Japanese Patent Laying-Open No. 2015-035862

  In the power conversion device disclosed in Patent Literatures 1-3, each bus bar has a plurality of branch portions extending from one flat plate portion, and each branch portion is connected to a terminal of each semiconductor module. There is a relative position error between each branch part and each terminal corresponding thereto, but the relative position error is forcibly eliminated by joining. The fact that the relative position error is forcibly eliminated means that the terminal is deformed. Internal stress is generated in the deformed terminal. Each of the many branches extending from one flat plate part has a relative position error with the corresponding terminal, and each terminal is joined to each branch so that each terminal has an internal position. Stress is generated. In order to reduce the inductance of the bus bar, it is preferable to make the branch portion as short as possible and make the flat portions of the two bus bars face each other close to the terminal. When the branch portion is shortened, the rigidity of the branch portion is increased, so that the internal stress generated in the terminal is increased. The present specification provides a technique for reducing the inductance by increasing the opposing range of two bus bars as much as possible and reducing the internal stress generated in each terminal as much as possible.

  The power conversion device disclosed in the present specification includes a laminated unit, a capacitor, a plate-like positive electrode bus bar, and a plate-like negative electrode bus bar. 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 is arranged next to the multilayer unit. The positive electrode bus bar has a plate shape, is joined to a positive electrode terminal extending from each side surface of the plurality of semiconductor modules, and is connected to one electrode of the capacitor. The negative electrode bus bar has a plate shape, is disposed to face the positive electrode bus bar, is joined to the negative electrode terminal extending from the side surface of each semiconductor module, and is connected to the other electrode of the capacitor. The positive electrode bus bar has a positive electrode bus bar first flat plate portion, a positive electrode bus bar second flat plate portion, and a plurality of positive electrode bus bar branch portions. The positive electrode bus bar first flat plate portion extends from the capacitor along the side surface of the semiconductor module to between the positive electrode terminal and the negative electrode terminal. The positive electrode bus bar second flat plate portion is bent from the edge of the positive electrode bus bar first flat plate portion between the positive electrode terminal and the negative electrode terminal, and extends in the extending direction of the positive electrode terminal. The plurality of positive electrode bus bar branch portions extend from the positive electrode bus bar second flat plate portion to the tip of each positive electrode terminal. Each positive bus bar branch is joined to the tip of each positive terminal. The negative electrode bus bar has a negative electrode bus bar first flat plate portion, a negative electrode bus bar second flat plate portion, and a plurality of negative electrode bus bar branch portions. The negative electrode bus bar first flat plate portion extends from the capacitor to between the positive electrode terminal and the negative electrode terminal in parallel with the positive electrode bus bar first flat plate portion. The negative electrode bus bar second flat plate portion is bent from the edge of the negative electrode bus bar first flat plate portion between the positive electrode terminal and the negative electrode terminal, and extends in the extending direction of the positive electrode terminal in parallel with the positive electrode bus bar second flat plate portion. Each of the plurality of negative electrode bus bar branch portions extends from the negative electrode bus bar second flat plate portion to the tip of each negative electrode terminal. Each negative electrode bus bar branch is connected to the tip of each negative electrode terminal.

  In the power converter disclosed in this specification, the positive electrode bus bar first flat plate portion and the negative electrode bus bar first flat plate portion face each other from the capacitor to between the positive electrode terminal and the negative electrode terminal of the semiconductor module. Between the positive electrode terminal and the negative electrode terminal, the positive electrode bus bar second flat plate portion and the negative electrode bus bar second flat plate portion face each other. When the first flat plate portions and the second flat plate portions face each other, the inductance of the bus bar is reduced. Each of the plurality of positive bus bar branch portions extending from the positive bus bar second flat plate portion is connected to the tip of the terminal of the semiconductor module. Each negative electrode bus bar branch is also connected to the tip of the corresponding negative electrode terminal. Since the branch portion of the bus bar is connected to the tip of the terminal, the distance from the base of the terminal to the connection location can be secured. By securing the distance from the terminal terminal, that is, the terminal fixing point to the connecting part with the branch part, the internal stress generated in the terminal is reduced. 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 | stacking unit, a bus bar, and a capacitor | condenser. It is a disassembled perspective view of a lamination | stacking unit, a bus bar, and a capacitor | condenser. It is an expanded view of a positive electrode bus bar. It is a front view of the assembly of a lamination | stacking unit, a bus bar, and a capacitor | condenser.

  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 (rear positive terminal 25a) of the seven semiconductor modules (seven sets of series circuits) are connected to one electrode of the smoothing capacitor 6, and the terminal on the lower potential side (rear negative terminal 25b) is connected. Connected to the other electrode of the smoothing capacitor 6. In FIG. 1, a conductive path within a broken line indicated by reference numeral 30 corresponds to a bus bar (positive bus bar) that connects the positive terminals 25 a and the smoothing capacitors 6 of the plurality of semiconductor modules 8 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 smoothing capacitor 6 to each other. Next, the structural relationship between the plurality of semiconductor modules 8 and 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 device 2, but only the assembly of the multilayer unit 20, the positive electrode bus bar 30, the negative electrode bus bar 40, and the smoothing capacitor 6 is illustrated, and 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 (8a-8g) 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 electrode terminals 25 a of the plurality of semiconductor modules 8 and one electrode 6 a of the smoothing capacitor 6 are connected by the positive electrode bus bar 30, and the plurality of negative electrode terminals 25 b and the other electrode of the smoothing capacitor 6 are connected by the negative electrode bus bar 40. The other electrode of the smoothing capacitor 6 is exposed on the lower surface of the smoothing capacitor 6 and is not visible in the figure. Description of the connection destination of the midpoint terminal 25c is omitted. FIG. 3 is an exploded perspective view of the assembly of the positive electrode bus bar 30, the negative electrode bus bar 40, the multilayer unit 20, and the smoothing capacitor 6.

  Although the positive electrode bus bar 30 is made of a single metal plate, for convenience of explanation, the electrode bus 39, the first flat plate portion 41, the second flat plate portion 32, and the plurality of branch portions 33 will be described separately. A developed view of the positive electrode bus bar 30 is shown in FIG. A portion above the broken line L2 corresponds to the electrode portion 39. A portion between the broken lines L <b> 2 and L <b> 3 corresponds to the first flat plate portion 31. The portion below the broken line L3 and excluding the branch portions 33a and 33b corresponds to the second flat plate portion 32 (32a and 32b). In FIG. 4, for the plurality of holes 34, reference numeral 34 is given only to the rightmost hole, and reference numerals are omitted for the other holes. Moreover, about the some branch part 33, the code | symbols 33a and 33b were attached | subjected only to two upper and lower branch parts of the left end, and the code | symbol was abbreviate | omitted to the other branch part. Reference numeral 33a indicates a branch portion between the broken line L3 and the broken line L4, and reference numeral 33b indicates a branch portion below the broken line L4.

  When the positive electrode bus bar 30a before bending in FIG. 4 is bent in the following order, the positive electrode bus bar 30 having the shape shown in FIGS. 2 and 3 is obtained. The plurality of first branch portions 43a between the broken line L3 and the broken line L4 are bent at right angles to the upper side of the drawing. The second branch 43b below the broken line L4 is bent at a right angle to the lower side of the drawing. The broken line L1 is folded at a right angle, and the broken lines L2-L4 are folded at a right angle. The plate portion 42a and the plate portion 42b are joined together to form the second flat plate portion 42.

  Returning to FIG. 2, the characteristics of the shape of the positive electrode bus bar 30 will be described. As described above, the positive electrode bus bar 30 includes the electrode portion 39, the first flat plate portion 31, the second flat plate portion 32, and the plurality of branch portions 33. The first flat plate portion 31 extends from the smoothing capacitor 6 along the side surface 80a of the semiconductor module 8 to between the positive electrode terminal 25a and the negative electrode terminal 25b. The second flat plate portion 32 is bent from the edge of the first flat plate portion 31 between the positive electrode terminal 25a and the negative electrode terminal 25b, and extends in the extending direction of the positive electrode terminal 25a (Z direction in the drawing). The second flat plate portion 32 extends in a direction away from the main body of the semiconductor module 8. Each of the plurality of branch portions 33 extends from the second flat plate portion 32 to the tip of each corresponding positive electrode terminal 25a. Each branch part 33 is joined to the tip of each corresponding positive electrode terminal 25a.

  A plurality of holes 34 are provided in the first flat plate portion 31, and the corresponding positive electrode terminal 25 a passes through each hole 34.

  The electrode portion 39 of the positive bus bar 30 is connected to one electrode 6 a of the smoothing capacitor 6. The entire positive electrode bus bar 30 connects the positive terminals 25 a of all the semiconductor modules 8 to one electrode 6 a of the smoothing capacitor 6.

  The negative electrode bus bar 40 also has a shape similar to that of the positive electrode bus bar 30. The negative electrode bus bar 40 is also made of a single metal plate. In FIG. 4, if the width between the broken line L1 and the broken line L2 is increased, a developed view of the negative electrode bus bar 40 is obtained. A method of bending the negative electrode bus bar 40 will be described with reference to FIG. A plurality of first branch portions 33a between the broken line L3 and the broken line L4 are bent at a right angle to the lower side of the drawing. The second branch portion 33b below the broken line L4 is bent at a right angle upward in the drawing. When the broken lines L1 and L3 are valley-folded at right angles and the broken lines L2 and L4 are folded at right angles, the negative electrode bus bar 40 is completed.

  Returning to FIG. 2, the shape of the negative electrode bus bar 40 will be described. The negative electrode bus bar 40 includes an electrode portion 49, a first flat plate portion 41, a second flat plate portion 42, and a plurality of branch portions 43. The first flat plate portion 41 extends from the smoothing capacitor 6 between the positive electrode terminal 25 a and the negative electrode terminal 25 b in parallel with the first flat plate portion 31 of the positive electrode bus bar 30. The second flat plate portion 42 is bent from the edge of the first flat plate portion 41 between the positive electrode terminal 25a and the negative electrode terminal 25b. The second flat plate part 42 extends in parallel with the second flat plate part 32 of the positive electrode bus bar 30 in the extending direction of the positive electrode terminal 25a (Z direction in the drawing). The second flat plate portion 42 extends in a direction away from the main body of the semiconductor module 8. Each of the plurality of branch portions 43 extends from the second flat plate portion 42 to the tip of each negative electrode terminal 25b. Each of the plurality of branch portions 43 is connected to the tip of the corresponding negative electrode terminal 25b.

  The first flat plate portion 41 of the negative electrode bus bar 40 is provided with a plurality of holes 44, and the corresponding positive electrode terminals 25 a pass through the respective holes 44. The negative electrode bus bar 40 is not in contact with the positive electrode bus bar 30 and is not in contact with the positive electrode terminal 25a.

  The electrode part 49 of the negative electrode bus bar 40 is connected to the other electrode of the smoothing capacitor 6. The entire negative electrode bus bar 40 connects the negative electrode terminals 25 b of all the semiconductor modules 8 to the other electrode of the smoothing capacitor 6.

  The advantages of the positive electrode bus bar 30 and the negative electrode bus bar 40 having the shapes described above will be described. FIG. 5 shows a front view of the power conversion device 2 (an assembly of the multilayer unit 20, the smoothing capacitor 6, and the bus bars 30, 40). The first flat plate portion 31 of the positive electrode bus bar 30 is close to and opposed to the first flat plate portion 41 of the negative electrode bus bar 40. The second flat plate portion 32 of the positive electrode bus bar 30 is close to and opposed to the second flat plate portion 42 of the negative electrode bus bar 40. Since the positive bus bar 30 and the negative bus bar 40 are in close proximity to each other, the magnetic field generated by one bus bar generates an eddy current in the other bus bar, thereby reducing the inductance of the one bus bar. Since the positive electrode bus bar 30 and the negative electrode bus bar 40 face each other over a wide area, the effect of reducing inductance is great.

  Further, the branch portion 33 of the positive electrode bus bar 30 is connected to the positive electrode terminal 25a at the tip of the positive electrode terminal 25a. Each branch portion 33 and the corresponding positive electrode terminal 25a have a position error before connection, and the position error is forcibly eliminated by joining. For this reason, internal stress is generated in the positive electrode terminal 25a. By joining the branch portion 33 at the tip of the positive electrode terminal 25a, the distance indicated by the symbol H in FIG. 5 is secured between the root of the positive electrode terminal 25a and the joint portion. The terminal 25a can be bent in the section of the distance H, and the internal stress generated in the terminal is reduced. The same applies to the negative electrode bus bar 40. The branch portion 43 of the negative electrode bus bar 40 is joined to the tip of the negative electrode terminal 25b. A distance H is ensured between the base of the negative electrode terminal 25b and the junction. Since a corresponding distance is secured from the root of the negative electrode terminal 25b to the joint location, the internal stress generated in the negative electrode terminal 25b is smaller than when the distance from the root to the joint location is short.

  In the power converter 2, the positive electrode bus bar 30 and the negative electrode bus bar 40 have the above-described structure, so that the inductance can be reduced and the internal stress generated in the connected positive electrode terminal 25a and the negative electrode terminal 25b can be reduced.

  Points to be noted regarding the technology described in the embodiments will be described. The first flat plate portion 31, the second flat plate portion 32, and the branch portion 33 of the positive electrode bus bar 30 of the embodiment are respectively referred to as “positive electrode bus bar first flat plate portion”, “positive electrode bus bar second flat plate portion”, and “positive electrode bus bar”. It corresponds to an example of “branch”. The first flat plate portion 41, the second flat plate portion 42, and the branch portion 43 of the negative electrode bus bar 40 of the embodiment are respectively referred to as “negative electrode bus bar first flat plate portion”, “negative electrode bus bar second flat plate portion”, and “negative electrode bus bar”. It corresponds to an example of “branch”.

  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 2b: Negative terminal 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 18: Input end 19 : Output end 20: Laminating unit 22: Cooler 25a: Positive electrode terminal 25b: Negative electrode terminal 25c: Midpoint terminal 28: Refrigerant supply port 29: Refrigerant discharge port 30: Positive electrode bus bar 31: First flat plate portion 32: Second flat plate portion 33: branch part 34: hole 39: electrode part 40: negative electrode bus bar 41: first flat plate part 42: second flat plate part 43: branch part 44: hole 49: electrode part 81: battery

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 disposed next to the multilayer unit;
A plate-like positive electrode bus bar that is joined to a positive electrode terminal extending from each side surface of the plurality of semiconductor modules and connected to one electrode of the capacitor;
A plate-like negative electrode bus bar disposed opposite to the positive electrode bus bar, joined to the negative electrode terminal extending from the side surface of each of the semiconductor modules, and connected to the other electrode of the capacitor;
With
The positive bus bar extends from the capacitor along the side surface of the semiconductor module between the positive electrode terminal and the negative electrode terminal, and between the positive electrode terminal and the negative electrode terminal. A positive bus bar second flat plate portion that is bent from an edge of the positive electrode bus bar first flat plate portion and extends in the extending direction of the positive electrode terminal, and extends from the positive electrode bus bar second flat plate portion to the tip of each positive electrode terminal. A plurality of positive bus bar branches, and each positive bus bar branch is joined to a tip of each positive terminal,
The negative electrode bus bar includes a negative electrode bus bar first flat plate portion extending from the capacitor to the positive electrode terminal and the negative electrode terminal in parallel to the positive electrode bus bar first flat plate portion, and between the positive electrode terminal and the negative electrode terminal. A negative electrode bus bar second flat plate portion bent from an edge of the negative electrode bus bar first flat plate portion and extending in parallel with the positive electrode bus bar second flat plate portion in an extending direction of the positive electrode terminal; A plurality of negative bus bar branches extending from the flat plate portion to the tip of each negative terminal, and each of the negative bus bar branches is connected to the tip of each of the negative terminals.
Power conversion device.

Images