JP7092268B2 - Power converter - Google Patents

Description

The techniques disclosed herein relate to power converters. In particular, the present invention relates to a power converter in which a laminated unit in which a plurality of power modules are laminated and a capacitor are connected by a bus bar.

The above-mentioned power converter is disclosed in, for example, Japanese Patent Application Laid-Open No. 2018-042424 (Reference 1), Japanese Patent Application Laid-Open No. 2018-042309 (Reference 2), and Japanese Patent Application Laid-Open No. 2018-026885 (Reference 3). Each power module contains one or more switching elements for power conversion. The conductor that electrically connects the terminal of the power module and the capacitor is sometimes called a bus bar. The power module and the capacitor are connected by two buses.

The power converter disclosed in Documents 1 and 2 has the following structure. Each power module included in the stacking unit contains a switching element for power conversion. A first terminal and a second terminal conducting with the switching element extend from the side surface of each power module. The capacitors are located next to the stacking unit. The first terminal of the plurality of power modules and one electrode of the capacitor are connected by the first bus bar. The second terminal of the plurality of power modules and the other electrode of the capacitor are connected by a second bus bar.

The first bus bar includes a first flat plate, a plurality of first holes, and a plurality of first branch portions. The first plate extends from the capacitor along the sides of the power module. The plurality of first holes are provided in the first flat plate. The first terminal of the corresponding power module passes through each of the plurality of first holes. Each first branch extends from the edge of the corresponding first hole along the first terminal and is connected to the first terminal. The second bus bar has the same structure as the first bus bar, and includes a second flat plate, a plurality of second holes, and a plurality of second branches. A second terminal passes through each second hole, and each second terminal is connected to each second branch portion. Specifically, the first bus bar and the second bus bar are a positive electrode bus bar connected to the positive electrode of the capacitor and a negative electrode bus bar connected to the negative electrode of the capacitor.

Hereinafter, for convenience of explanation, the stacking direction of the plurality of power modules will be referred to as a first direction. In the power converter disclosed in Document 1, the first flat plate and the second flat plate are provided with ribs at both ends in the first direction. By providing the ribs, the rigidity of the first flat plate and the second flat plate is improved, and the deformation of the first flat plate and the second flat plate is suppressed.

Hereinafter, for convenience of explanation, a direction orthogonal to the first direction and parallel to the first flat plate is referred to as a second direction. Due to the ribs, the deformation of the first flat plate (second flat plate) when viewed from the first direction is suppressed. However, the ribs do not significantly contribute to the suppression of deformation of the first flat plate (second flat plate) when viewed from the second direction. This specification describes the deformation (particularly when the second plate) of the first plate (second plate) of the first bus bar (second bus bar) connecting the plurality of first terminals (second terminals) of the laminated unit and the capacitor is formed. (Deformation) is provided.

The power converter disclosed in the present specification includes a laminated unit in which a plurality of power modules are laminated, a capacitor arranged next to the laminated unit, a first bus bar, and a second bus bar. Each power module contains a switching element for power conversion. The first terminal and the second terminal conducting with the switching element extend from the side surface of the power module. The first terminals of the plurality of power modules are arranged in a row along the stacking direction (first direction) of the power modules, and the plurality of second terminals are arranged in a row in parallel with the row of the first terminals.

The first bus bar is connected to the first terminal of a plurality of power modules and is connected to one electrode of the capacitor. The first bus bar includes a first flat plate extending from the capacitor along the side surface of the power module (the side surface where the first terminal and the second terminal are provided). The first flat plate is provided with a plurality of first holes and a plurality of first branch portions. The first terminal passes through each of the plurality of first holes. Each first branch extends from the edge of each first hole and is connected to each first terminal.

The second bus bar is connected to the second terminal of the plurality of power modules and is connected to the other electrode of the capacitor. The second bus bar includes a second plate extending parallel to the first plate from the capacitor. The second flat plate is provided with a plurality of second holes and a plurality of second branch portions. The second terminal passes through each of the plurality of second holes. Each second branch extends from the edge of each second hole and is connected to each second terminal.

A first rib is provided on the edge on the side far from the capacitor of the first flat plate. The first rib suppresses the deformation of the first flat plate when viewed from the second direction. A second rib may be provided on the edge far from the capacitor of the second flat plate. The second rib suppresses the deformation of the second flat plate when viewed from the second direction. The first rib and the second rib extend from the respective flat plates along the third direction. The third direction is a direction orthogonal to both the first direction and the second direction. The first rib and the second rib extend in a direction away from each other in the third direction. The first rib and the second rib extending in the direction away from each other do not interfere with each other.

Details and further improvements to the techniques disclosed herein will be described in the "Modes for Carrying Out the Invention" section below.

It is a block diagram of the electric power system of the electric vehicle including the electric power converter of an Example. It is a perspective view of the assembly of a laminated unit, a bus bar and a capacitor unit. It is an exploded perspective view of an assembly. It is a perspective view of the assembly of the power converter of a modification. It is an enlarged view near the notch in FIG.

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

The power converter 2 is connected to the battery 81 via the system main relay 82. The power converter 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 alternating current.

The voltage converter circuit 12 is a bidirectional DC-DC converter capable of performing both step-up operation and step-down operation. In the boosting operation, the voltage converter circuit 12 boosts the voltage applied to the terminal on the battery side and outputs it to the terminal on the inverter side. In the step-down operation, the voltage converter circuit 12 steps down the voltage applied to the terminal on the inverter side and outputs it to the terminal on the battery side. For convenience of explanation, in the following, the terminal on the battery side (low voltage side) will be referred to as an input terminal 18, and the terminal on the inverter side (high voltage side) will be referred to as an output terminal 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 end 18" and "output end 19" are for convenience of explanation, and as described above, since the voltage converter circuit 12 is a bidirectional DC-DC converter, it is an output end. Power may flow from 19 to the input end 18.

The voltage converter circuit 12 is composed of 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. One end of the reactor 7 is connected to the input positive electrode end 18a, and the other end is connected to the midpoint of the series circuit. The filter capacitor 5 is connected between the input positive electrode end 18a and the input negative electrode end 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 will be omitted.

The circuit in the range of the broken line rectangle indicated by the reference numeral 8a corresponds to the power module 8a described later. Reference numerals 25a and 25b indicate terminals extending from the power module 8a. Reference numeral 25a indicates a terminal (positive electrode terminal 25a) conducting with the high potential side of the series circuit of the switching elements 9a and 9b. Reference numeral 25b represents a terminal (negative electrode terminal 25b) conducting with the low potential side of the series circuit of the switching elements 9a and 9b. As will be described next, the notation of positive electrode terminal 25a and negative electrode terminal 25b is also used in other power modules. The terminal connected to the midpoint of the series connection of the two switching elements is referred to as a midpoint terminal.

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 form a series circuit, respectively. Diodes are connected in anti-parallel to each switching element. The terminal on the high potential side (positive electrode terminal 25a) of the three sets of series circuits is connected to the output positive electrode end 19a of the voltage converter circuit 12, and the terminal on the low potential side (negative electrode terminal 25b) of the three sets of series circuits is voltage. It is connected to the output negative electrode end 19b of the converter circuit 12. Three-phase alternating current (U phase, V phase, W phase) is output from the midpoint terminal of the three sets of series circuits. Each of the three sets of series circuits corresponds to the power 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, the specific circuit is not shown in FIG. Similar to the inverter circuit 13a, the inverter circuit 13b also has a configuration in which three sets of series circuits of two switching elements are connected in parallel. The terminal on the high potential side of the three sets of series circuits is connected to the output positive electrode end 19a of the voltage converter circuit 12, and the terminal on the low potential side of the three sets of series circuits is connected to the output negative electrode terminal 19b of the voltage converter circuit 12. Has been done. The hardware corresponding to each series circuit is referred to as a power module 8e, 8f, 8g.

A smoothing capacitor 6 is connected in parallel to the input ends 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. The smoothing capacitor 6 eliminates the pulsation of the output current of the voltage converter circuit 12.

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

In FIG. 1, each of the broken lines 8a-8g corresponds to a power module. The power converter 2 includes seven sets of a series circuit of two switching elements. As hardware, two switching elements constituting a series circuit and a diode connected in antiparallel to each switching element are housed in one package (main body of a power module). In the following, when any one of the power modules 8a-8g is shown without distinction, it is referred to as a power module 8.

The high potential side terminal (positive electrode terminal 25a) of the seven power modules (7 sets of series circuits) is connected to the positive electrode of the smoothing capacitor 6, and the low potential side terminal (negative electrode terminal 25b) is the negative of the smoothing capacitor 6. Connected to the electrode. In FIG. 1, the conductive path in the broken line indicated by reference numeral 30 corresponds to a bus bar (positive electrode bus bar) that interconnects the positive electrode terminals 25a of the plurality of power modules 8 and the positive electrodes of the smoothing capacitor 6. The conductive path in the broken line indicated by reference numeral 40 corresponds to a bus bar (negative electrode bus bar) that interconnects the plurality of negative electrode terminals 25b and the negative electrodes of the smoothing capacitor 6. Next, the structures of the plurality of power 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 converter 2. In FIG. 2, the housing of the power converter 2 and some parts are not shown. The plurality of power modules 8 (8a-8g) together with the plurality of coolers 22 constitute a laminated unit 20. Since the power modules 8a-8g all have the same shape, in FIGS. 2 and 3, the reference numeral 8 is attached only to the leftmost power module, and the reference numeral is omitted for the other power modules. Further, in FIGS. 2 and 3, the reference numeral 22 is attached only to the two leftmost coolers, and the reference numeral is omitted for the other coolers. FIG. 3 will be described later.

FIG. 2 is a perspective view of the power converter 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 drawn, and the other parts are not shown. In the stacking unit 20, a plurality of power modules 8 are laminated. The stacking unit 20 is a device in which a plurality of card-type coolers 22 are arranged in parallel, and a card-type power module 8 is sandwiched between adjacent coolers 22. The card-type power module 8 has its wide surface facing the cooler 22. The X direction of the coordinate system in the figure corresponds to the stacking direction of the plurality of power modules 8. In the following figures, the X direction also indicates the stacking direction.

Three terminals (positive electrode terminal 25a, negative electrode terminal 25b, midpoint terminal 25c) extend from one side surface 80a of each power module 8. In FIGS. 2 and 3, the reference numerals 25a, 25b, and 25c are attached only to the terminals of the power module 8 located at the left end of the laminated unit 20, and the reference numerals indicating the terminals are omitted from the remaining power modules 8.

As described above, the positive electrode terminal 25a and the negative electrode terminal 25b are a terminal on the high potential side and a terminal on the low potential side of the series circuit housed in the power module 8. The midpoint terminal 25c is a terminal conducting with the midpoint of the series circuit. In other words, all three terminals 25a-25c are conducting with the switching element inside the power module 8. The three terminals 25a-25c extend in the positive direction of the Z axis in the drawing from one side surface 80a intersecting the wide surface of the power module 8. A plurality of control terminals extend from the opposite side surface of one side surface 80a in the negative direction of the Z axis in the drawing. The control terminals are a gate terminal conducting with the gate electrode of the switching element built in the power module 8, a signal terminal conducting with a temperature sensor and a current sensor built in the power module 8, and the like. ..

The rightmost cooler 22 in the figure is provided with a refrigerant supply port 28 and a refrigerant discharge port 29. The 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 the refrigerant discharge port 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 power module 8 while passing through the cooler 22. The refrigerant that has absorbed heat is discharged from the laminated unit 20 through the other connecting pipe and the refrigerant discharge port 29. Since each power module 8 is cooled from both sides thereof, the laminated unit 20 has high cooling performance.

The three terminals 25a-25c of each power module 8 are all flat plates. The positive electrode terminals 25a of the plurality of power modules 8 are arranged in a row in the X direction (stacking direction) so as to face the flat surface of the positive electrode terminals 25a of the adjacent power modules 8. The negative electrode terminals 25b of the plurality of power modules 8 are also arranged in a row in the X direction (stacking direction) so as to face the flat surface of the negative electrode terminals 25b of the adjacent power modules 8. The same applies to the midpoint terminals 25c of the plurality of power modules 8. The rows of the positive electrode terminals 25a, the rows of the negative electrode terminals 25b, and the rows of the midpoint terminals 25c of the plurality of power modules 8 are parallel to each other.

A capacitor unit 60 is arranged next to the laminated unit 20. The capacitor unit 60 is long along the stacking direction (X direction in the figure) of the power module 8. The capacitor unit 60 is lined up with the stacking unit 20 in a direction (Y direction) intersecting the stacking direction. Two capacitor elements 61 (described later) are housed in the case of the capacitor unit 60. The positive electrode bus bar 30 connects the positive electrode terminals 25a of the plurality of power modules 8 to the capacitor elements in the capacitor unit 60, and the negative electrode bus bar 40 connects the negative electrode terminals 25b of the plurality of power modules 8 and the capacitors. Connect the capacitor element in the unit 60.

FIG. 3 shows an exploded perspective view of the assembly of the positive electrode bus bar 30, the negative electrode bus bar 40, the laminated unit 20, and the capacitor element 61 (capacitor unit 60). The capacitor unit 60 in FIG. 2 accommodates two capacitor elements 61. In FIG. 3, the case of the capacitor unit 60 is omitted, and the internal capacitor element 61 is drawn. Although details are omitted, the periphery of the capacitor element 61 in the case of the capacitor unit 60 is filled with a filler. The capacitor element 61 corresponds to the smoothing capacitor 6 in FIG.

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

The positive electrode bus bar 30 includes a plate-shaped electrode portion 39 and a flat plate 31. The flat plate 31 is provided with a plurality of positive electrode terminal holes 32 and a plurality of branch portions 33. The electrode portion 39 is connected to the positive electrode 61a of the capacitor element 61. The plurality of positive electrode terminal holes 32 are arranged in a row along the X direction. A branch portion 33 extends in the Z direction from the edge of each positive electrode terminal hole 32. The positive electrode terminal 25a of the power module 8 corresponding to each positive electrode terminal hole 32 passes through, and the positive electrode terminal 25a and the branch portion 33 are joined by welding.

The negative electrode bus bar 40 includes a plate-shaped electrode portion 49 and a flat plate 41. The flat plate 41 is provided with a plurality of negative electrode terminal holes 42 and a plurality of branch portions 43. The electrode portion 49 is connected to the negative electrode 61b of the capacitor element 61. The plurality of negative electrode terminal holes 42 are arranged in a row along the X direction. A branch portion 43 extends in the Z direction from the edge of each negative electrode terminal hole 42. The negative electrode terminal 25b of the corresponding power module 8 passes through each negative electrode terminal hole 42, and the negative electrode terminal 25b and the branch portion 43 are joined.

The negative electrode bus bar 40 is located on the opposite side of the laminated unit 20 of the positive electrode bus bar 30. The negative electrode bus bar 40 is provided with a plurality of positive electrode terminal holes 45. The positive electrode terminal 25a of the power module 8 and the branch portion 33 of the positive electrode bus bar 30 pass through each of the positive electrode terminal holes 45. The flat plate 31 of the positive electrode bus bar 30 and the flat plate 41 of the negative electrode bus bar 40 are arranged in parallel with the insulating plate 50 (described later) interposed therebetween, and face each other in close proximity to each other. When a current flows through one of the bus bars, a magnetic field is generated around the bus bar due to the current. There is a positive correlation between the magnitude of the magnetic field and the inductance of the bus bar. The larger the magnetic field, the larger the inductance. When the flat plate 31 of the positive electrode bus bar 30 and the flat plate 41 of the negative electrode bus bar 40 are in close proximity to each other, an eddy current is generated in the other bus bar by the magnetic field of one bus bar. The generation of eddy currents weakens the magnetic field of one bus bar. The weakening of the magnetic field means that the inductance becomes smaller. By arranging the flat plates 31 and 41 of the bus bar close to each other, the inductance of the bus bar can be reduced.

The 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 tubular portions 53. Ribs 57 extending in the Y direction are provided on both sides of the insulating plate 50 in the stacking direction (X direction). As shown in FIG. 2, the rib 57 is sandwiched between the reinforcing rib 37 of the positive electrode bus bar 30 and the reinforcing rib 47 of the negative electrode bus bar 40, and insulates both of them. Reinforcing ribs 37 and 47 will be described later.

The tubular portion 53 of the insulating plate 50 passes through the positive electrode terminal hole 45 of the negative electrode bus bar 40. The branch portion 33 of the positive electrode bus bar 30 and the positive electrode terminal 25a of the power module 8 pass through the inside of the tubular portion 53. The tubular portion 53 reliably insulates the positive electrode terminal 25a and the branch portion 33 from the negative electrode bus bar 40.

Both ends of the flat plate 31 of the positive electrode bus bar 30 in the stacking direction (X direction) are bent at right angles. The portion bent at a right angle is referred to as a reinforcing rib 37. Both ends of the flat plate 41 of the negative electrode bus bar 40 in the stacking direction (X direction) are also bent at right angles. The portion bent at a right angle is referred to as a reinforcing rib 47. As described above, the capacitor element 61 is housed in the case and is embedded in the filler in the case. Therefore, a part of the positive electrode bus bar 30 and a part of the negative electrode bus bar 40 are also embedded in the filler in the case of the capacitor unit 60. Naturally, the electrode portions 39 and 49 will be embedded in the filler. A part 31a of the flat plate 31 of the positive electrode bus bar 30 is also embedded in the filler, and a part 41a of the flat plate 41 of the negative electrode bus bar 40 is also embedded in the filler. The portion indicated by reference numerals 31b and 41b is an exposed portion exposed from the capacitor unit 60 in the flat plates 31 and 41. A part 37a of the reinforcing rib 37 and a part 47a of the reinforcing rib 47 are also embedded in the filler.

Reinforcing ribs 38 are also provided on the edge of the positive electrode bus bar 30 (flat plate 31) farthest from the capacitor element 61. The reinforcing rib 38 is provided on the edge of the two edges extending in the X direction of the flat plate 31 on the side farther from the capacitor element 61. Reinforcing ribs 48 are also provided on the edge of the negative electrode bus bar 40 (flat plate 41) on the side far from the capacitor element 61. The reinforcing rib 48 is provided on the edge of the two edges extending in the X direction of the flat plate 41, which is far from the capacitor element 61.

The reinforcing rib 38 extends from the flat plate 31 in the −Z direction. The reinforcing rib 48 extends from the flat plate 41 in the + Z direction. That is, the reinforcing rib 38 and the reinforcing rib 48 extend in a direction away from each other. Therefore, even if the positive electrode bus bar 30 and the negative electrode bus bar 40 overlap, the reinforcing rib 38 and the reinforcing rib 48 do not interfere with each other.

The reinforcing rib 37 described above increases the rigidity of the positive electrode bus bar 30 (flat plate 31) against bending when viewed from the X direction. In other words, the reinforcing rib 37 suppresses deformation of the positive electrode bus bar 30 (flat plate 31) around the axis extending in the X direction. On the other hand, the reinforcing rib 38 increases the rigidity of the positive electrode bus bar 30 (flat plate 31) against bending when viewed from the Y direction. In other words, the reinforcing rib 38 suppresses deformation of the positive electrode bus bar 30 (flat plate 31) around the axis extending in the Y direction.

The same applies to the reinforcing rib 47. The reinforcing rib 47 increases the rigidity of the negative electrode bus bar 40 (flat plate 41) against bending when viewed from the X direction. In other words, the reinforcing rib 47 suppresses deformation of the negative electrode bus bar 40 (flat plate 41) around the axis extending in the X direction. The reinforcing rib 48 increases the rigidity of the negative electrode bus bar 40 (flat plate 41) against bending when viewed from the Y direction. In other words, the reinforcing rib 48 suppresses deformation of the negative electrode bus bar 40 (flat plate 41) around the axis extending in the Y direction.

In the manufacturing process of the power converter 2, the branch portion 33 of the positive electrode bus bar 30 is joined to the positive electrode terminal 25a of the power module 8. At the time of joining, the branch portion 33 and the positive electrode terminal 25a are gripped by the chuck. The flat plate 31 of the positive electrode bus bar 30 may be deformed by the force received from the chuck. The reinforcing rib 38 suppresses deformation of the flat plate 31 due to the force of the chuck. The same applies to the negative electrode bus bar 40, and the reinforcing rib 48 suppresses deformation of the flat plate 41 due to the force of the chuck (the force sandwiching the branch portion 43 and the negative electrode terminal 25b).

The reinforcing ribs 37 and 38 are made by bending a single flat plate (flat plate 31). The reinforcing ribs 47 and 48 are made by bending a single flat plate (flat plate 41).

FIG. 4 shows a perspective view of the power converter 2a of the modified example. FIG. 4 corresponds to FIG. In FIG. 4, a reference numeral (8a-8g) unique to each of the plurality of power modules 8 is attached.

The reinforcing ribs 138 and the reinforcing ribs 148 of the power converter 2a of the modified example are different from the reinforcing ribs 38 and 48 of the power converter 2 of the embodiment. Except for the reinforcing ribs 138 and 148, the structure of the power converter 2a is the same as that of the power converter 2.

The reinforcing rib 148 has two notches 149a and 149b. FIG. 5 shows an enlarged view of the vicinity of the notch 149a. The notches 149a and 149b reach the negative electrode terminal hole 42. As described above, the reinforcing rib 148 suppresses the deformation of the flat plate 41 when viewed from the Y direction. On the other hand, by providing the reinforcing rib 148, the rigidity of the flat plate 41 is increased, and there is a possibility that stress is locally concentrated when a force is applied. By providing the notches 149a and 149b, the stress concentration when the flat plate 41 receives a force is relaxed.

Further, the notch 149a is provided between the power module 8a and the power module 8b. More specifically, the notch 149a is provided between the midpoint terminal 25c of the power module 8a and the midpoint terminal 25c of the power module 8b. As described with reference to FIG. 1, the power module 8a is used in the voltage converter circuit 12, and the power module 8b is used in the inverter circuit 13a. That is, the notch 149a is provided between the two power modules 8a and 8b used in different conversion circuits. The switching elements of the power modules 8a and 8b operate at timings independent of each other, and switching noise interferes with each other. The notch 149a reduces noise interference from switching elements that operate at mutually independent timings.

The notch 149b is provided between the power module 8d and the power module 8e. More specifically, the notch 149b is provided between the midpoint terminal 25c of the power module 8d and the midpoint terminal 25c of the power module 8e. The power module 8d is used in the inverter circuit 13a, and the power module 8e is used in the inverter circuit 13b. The switching elements of the power modules 8d and 8e operate at timings independent of each other, and switching noise interferes with each other. The notch 149b also reduces noise interference from switching elements that operate at mutually independent timings.

Although it is hidden and invisible in FIG. 4, the reinforcing rib 138 of the positive electrode bus bar 30 is also provided with a similar notch. The notch provided in the reinforcing rib 138 has the same effect as the notch 149a and 149b of the reinforcing rib 148.

The points to be noted regarding the techniques described in the examples will be described. The negative electrode bus bar 40 of the embodiment corresponds to an example of the first bus bar. Each of the flat plate 41, the negative electrode terminal hole 42, and the branch portion 43 of the negative electrode bus bar 40 corresponds to an example of the first flat plate, the first hole, and the first branch portion. The positive electrode bus bar 30 of the embodiment corresponds to an example of the second bus bar. Each of the flat plate 31, the positive electrode terminal hole 32, and the branch portion 33 of the positive electrode bus bar 30 corresponds to an example of the second flat plate, the second hole, and the second branch portion. The reinforcing rib 48 corresponds to an example of the first rib. The reinforcing rib 38 corresponds to an example of the second rib. The X direction of the coordinate system in the figure corresponds to the first direction, and the Y direction corresponds to the second direction.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above. The technical elements described herein or in the drawings exhibit their 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 techniques exemplified in the present specification or the drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes itself has technical usefulness.

Claims (6)

A laminated unit that houses a switching element for power conversion, and has a plurality of power modules in which a first terminal and a second terminal extending from the side surface of the switching element are laminated in the first direction. ,
With the capacitor placed next to the laminated unit,
A first bus bar that is joined to the first terminal of the plurality of power modules and is connected to one of the electrodes of the capacitor.
A second bus bar that is joined to the second terminal of the plurality of power modules and is connected to the other electrode of the capacitor.
Equipped with
The first terminals of the plurality of power modules are arranged in a row along the first direction, and the plurality of second terminals are arranged in a row in parallel with the row of the first terminals.
The first bus bar is a first flat plate extending from the capacitor along the side surface of the power module, and a plurality of first holes provided in the first flat plate, each of which has a first terminal. It comprises a plurality of first holes passing through and a plurality of first branches extending from the edge of each of the first holes and connected to each of the first terminals.
The second bus bar is a second plate extending from the capacitor in parallel with the first plate, and a plurality of second holes provided in the second plate, through which the second terminal passes. A plurality of second holes extending from the edges of the respective second holes and a plurality of second branches extending from the edges of the respective second holes and connected to the respective second terminals.
A power converter in which a first rib is provided on an edge of the first flat plate on the side far from the capacitor. A second rib is provided on the edge of the second flat plate extending in the first direction and far from the capacitor, and the first rib and the second rib are separated from each other. The power converter according to claim 1, which is extended. The power converter according to claim 1 or 2, wherein the first flat plate and the first rib are made of one metal plate. The power converter according to any one of claims 1 to 3, wherein the first rib has a notch that reaches the first flat plate. The power converter according to claim 4, wherein the first rib includes the plurality of notches. 4. The notch is provided between the first power module used in the first power conversion circuit and the second power module used in the second power conversion circuit. Or the power converter according to 5.

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