Power conversion device

Abstract

To provide a power conversion device capable of suppressing parasitic inductance.SOLUTION: A power conversion device includes an inverter, a capacitor, and a pair of bus bars electrically connecting the inverter and the capacitor. One bus bar of the pair of bus bars has a connection portion 131 electrically connected to the capacitor and an adjacent portion 113 adjacent to the connection portion so as to surround the periphery of the connection portion, and at least a portion of the adjacent portion faces the other bus bar of the pair of bus bars.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The disclosure in this specification relates to a power conversion device.

Background Art

[0002] Patent Document 1 discloses a power conversion device including a pair of bus bars that electrically connect a semiconductor device and a capacitor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Further suppression of parasitic inductance in the portion connecting the bus bar and the capacitor is required.

[0005] One disclosed object is to provide a power conversion device that suppresses parasitic inductance.

Means for Solving the Problems

[0006] To achieve the above object, in a "power conversion device" according to one aspect of the present disclosure, an inverter (5) that converts power, a capacitor (50) that supplies power to the inverter while smoothing the power supplied from a DC power source (2), and a pair of bus bars (110) that electrically connect the inverter and the capacitor, wherein one of the pair of bus bars (110P) has a connection portion (131) electrically connected to the capacitor and an adjacent portion (113) adjacent to the connection portion so as to surround the periphery of the connection portion. At least a part of the adjacent portion faces the other bus bar (110N) among the pair of bus bars.

[0007] In the present disclosure, one of the pair of bus bars has a connection portion that electrically connects the one bus bar and the capacitor, and an adjacent portion that is adjacent to the connection portion so as to surround the periphery of the connection portion. And at least a part of the adjacent portion faces the other bus bar among the pair of bus bars. Thereby, it becomes possible to suppress the parasitic inductance in the adjacent portion.

[0008] Note that the reference numerals in the parentheses above only show an example of the correspondence relationship with the specific configuration in the embodiments described later, and do not limit the technical scope in any way.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0010] Hereinafter, a plurality of embodiments will be described with reference to the drawings. In each embodiment, corresponding components may be denoted by the same reference numerals, and redundant descriptions may be omitted. When only a part of the configuration is described in each embodiment, the configuration of other embodiments described previously can be applied to the other parts of the configuration. Also, not only the combinations of configurations explicitly shown in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined with each other as long as there is no problem with the combination, even if not explicitly shown.

[0011] The electric conversion device of this embodiment is, for example, a device applied to a moving body having a rotating electric machine as a drive source. The moving body is, for example, an electric vehicle such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric aircraft such as a drone or an electric vertical takeoff and landing aircraft (eVTOL), a ship, a construction machine, or an agricultural machine. Hereinafter, an example applied to a vehicle will be described.

[0012] (Embodiment) First, based on FIG. 1, the schematic configuration of the vehicle drive system will be described.

[0013] <Vehicle drive system> As shown in FIG. 1, the vehicle drive system 1 includes a DC power source 2, a motor generator 3, and a power conversion device 4.

[0014] The DC power source 2 is a DC voltage source composed of a rechargeable secondary battery. The motor generator 3 is a three-phase AC rotating electric machine. The motor generator 3 functions as a driving source for the vehicle to travel, that is, as an electric motor. The motor generator 3 functions as a generator during regeneration. The power conversion device 4 performs power conversion between the DC power source 2 and the motor generator 3.

[0015] <Circuit configuration of the power conversion device> Figure 1 shows the circuit configuration of the power conversion device 4. The power conversion device 4 includes at least a power conversion circuit. The power conversion circuit of the present embodiment is an inverter 5. The power conversion device 4 may further include a smoothing capacitor 6, a drive circuit 7, and the like.

[0016] The smoothing capacitor 6 supplies power to the inverter 5 while smoothing the power supplied from the DC power supply 2. The smoothing capacitor 6 mainly smoothes the DC voltage supplied from the DC power supply 2. The smoothing capacitor 6 is connected to a P line 8 which is a high-potential side power supply line and an N line 9 which is a low-potential side power supply line. The P line 8 is connected to the positive electrode of the DC power supply 2, and the N line 9 is connected to the negative electrode of the DC power supply 2. The positive electrode of the smoothing capacitor 6 is connected to the P line 8 between the DC power supply 2 and the inverter 5. The negative electrode of the smoothing capacitor 6 is connected to the N line 9 between the DC power supply 2 and the inverter 5. The smoothing capacitor 6 is connected in parallel with the DC power supply 2.

[0017] The inverter 5 is a DC-AC conversion circuit. The inverter 5 converts a DC voltage into a three-phase AC voltage according to switching control by a control circuit (not shown) and outputs it to the motor generator 3. Thereby, the motor generator 3 is driven to generate a predetermined torque. During regenerative braking of the vehicle, the inverter 5 converts the three-phase AC voltage generated by the motor generator 3 receiving the rotational force from the wheels into a DC voltage according to switching control by the control circuit and outputs it to the P line 8. Thus, the inverter 5 performs bidirectional power conversion between the DC power supply 2 and the motor generator 3.

[0018] The inverter 5 is configured to include three-phase upper and lower arm circuits 10. The upper and lower arm circuits 10 are sometimes referred to as legs. The upper and lower arm circuits 10 each have an upper arm 10H and a lower arm 10L. The upper arm 10H and the lower arm 10L are serially connected between the P line 8 and the N line 9 with the upper arm 10H on the P line 8 side.

[0019] The connection point between the upper arm 10H and the lower arm 10L, that is, the midpoint of the upper and lower arm circuit 10, is connected to the corresponding phase winding 3a in the motor generator 3 via the output line 11. Among the upper and lower arm circuits 10, the U-phase upper and lower arm circuit 10U is connected to the U-phase winding 3a via the output line 11. The V-phase upper and lower arm circuit 10V is connected to the V-phase winding 3a via the output line 11. The W-phase upper and lower arm circuit 10W is connected to the W-phase winding 3a via the output line 11.

[0020] The upper and lower arm circuits 10 (10U, 10V, 10W) have a series circuit 12. The series circuit 12 included in the upper and lower arm circuits 10 may be one or a plurality. In the case of a plurality, the series circuits 12 are connected in parallel to each other to form the upper and lower arm circuit 10 for one phase. The series circuit 12 is configured by serially connecting a switching element on the upper arm 10H side and a switching element on the lower arm 10L side between the P line 8 and the N line 9.

[0021] The number of the switching elements on the high side and the low side constituting the series circuit 12 is not particularly limited. It may be one or a plurality. The series circuit 12 of the present embodiment has two switching elements on the high side and two switching elements on the low side. The two switching elements on the high side are connected in parallel, and the two switching elements on the low side are connected in parallel to form one series circuit 12. That is, each of the six arms 10H, 10L of the upper and lower arm circuits 10 for three phases is constituted by two switching elements connected in parallel to each other.

[0022] In this embodiment, a SiC-MOSFET is adopted as each switching element, hereinafter referred to as MOSFET13. MOSFET is the abbreviation of Metal Oxide Semiconductor Field Effect Transistor. The two MOSFET13s on the high side connected in parallel are turned on and off at the same timing with each other by a common gate drive signal (drive voltage). The two MOSFET13s on the low side connected in parallel are turned on and off at the same timing with each other by a common gate drive signal (drive voltage).

[0023] Note that the switching element is not limited to MOSFET13. For example, an IGBT may be adopted. IGBT is the abbreviation of Insulated Gate Bipolar Transistor.

[0024] The drive circuit 7 drives the switching elements that constitute a power conversion circuit such as the inverter 5. The drive circuit 7 supplies a drive voltage to the gate of the corresponding MOSFET13 based on the drive command of the control circuit. The drive circuit drives the corresponding MOSFET13, that is, turns it on and off, by applying the drive voltage. The drive circuit may be referred to as a driver.

[0025] The power conversion device 4 may include a control circuit for the switching element. The control circuit generates a drive command for operating the MOSFET13 and outputs it to the drive circuit 7. The control circuit generates a drive command based on, for example, a torque request input from a higher-level ECU (not shown) and signals detected by various sensors. ECU is the abbreviation of Electronic Control Unit. The control circuit may be provided in the higher-level ECU.

[0026] <Structure of Power Conversion Device> FIG. 2 is a plan view showing the power conversion device 4 of the present embodiment. In FIG. 2, the circuit board is omitted so that the arrangement of the semiconductor modules and the cooler can be understood. Also, in FIG. 2, a part of the relay terminal portions 136P and 136N of the relay busbar unit 100 is omitted. The white arrow in FIG. 2 indicates the direction in which the refrigerant flows. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2. In FIG. 3, for the sake of convenience, only the semiconductor element and the sealing body are shown as the main body portion. Also, the portion of the external connection terminal sealed in the sealing body is omitted.

[0027] The power conversion device 4 of the present embodiment includes a base 20 having a first cooler 21, a semiconductor module 30, a relay busbar unit 100, and a second cooler 40. The power conversion device 4 may include a capacitor 50. The power conversion device 4 may include a circuit board 60. The power conversion device 4 may include a capacitor busbar 51. As an example, the power conversion device 4 of the present embodiment includes a base 20 having a first cooler 21, a plurality of semiconductor modules 30, a second cooler 40, a capacitor 50, a relay busbar unit 100, a capacitor busbar 51, and a circuit board 60.

[0028] The relay busbar unit 100 has a relay busbar 110 and a fixing member 120. The relay busbar 110 is a pair of busbars that electrically connect the inverter 5 and the smoothing capacitor 6. The relay busbar 110 includes a relay P busbar 110P and a relay N busbar 110N. Of the relay busbar 110, one busbar is also referred to as the relay P busbar 110P, and the other busbar is also referred to as the relay N busbar 110N. The relay P busbar 110P and the relay N busbar 110N are plate-shaped metal members. The fixing member 120 is a member that fixes the relay P busbar 110P and the relay N busbar 110N so as to face each other with a predetermined interval d1. Note that the fixing member 120 is also a member that holds the relay P busbar 110P and the relay N busbar 110N in a predetermined positional relationship. The fixing member 120 is made of a resin having electrical insulation properties and is a member for achieving electrical insulation between the relay P busbar 110P and the relay N busbar 110N.

[0029] Hereinafter, the arrangement direction of the plurality of semiconductor modules 30 is defined as the X direction. The stacking direction of the first cooler 21, the semiconductor module 30, and the second cooler 40, which is orthogonal to the X direction, is defined as the Z direction. The direction orthogonal to both the X direction and the Z direction is defined as the Y direction. The Y direction corresponds to one direction orthogonal to the stacking direction. The X direction, the Y direction, and the Z direction are in a mutually orthogonal positional relationship. A plan view from the Z direction may simply be referred to as a plan view. When explaining the relative positions of two members, the position of the member closer to the base 20 in the Z direction may be shown as downward, and the position of the member farther from the base 20 may be shown as upward. First, the schematic configuration of each element will be described.

[0030] <Base and First Cooler> The base 20 mounts the semiconductor module 30 on one of its surfaces 20a. The base 20 is a support member that supports the semiconductor module 30. In this embodiment as an example, the semiconductor module 30 and the capacitor 50 are arranged on one surface of the base 20. The base 20 is formed using a metal material such as aluminum.

[0031] The base 20 has a first cooler 21. The first cooler 21 is configured using the base 20. The first cooler 21 is a cooling portion in the base 20. The first cooler 21 may include a flow path through which a refrigerant flows, or may be a heat dissipation member including a heat sink or heat dissipation fins. As an example, the first cooler 21 of this embodiment is configured to include a flow path 211 formed inside the base 20 and a peripheral portion of the flow path 211 in the base 20, as shown in FIGS. 2 and 3. The refrigerant 212 flows through the flow path 211. As the refrigerant 212, for example, a phase-changing refrigerant such as water or ammonia, or a non-phase-changing refrigerant such as an ethylene glycol-based refrigerant can be used. The first cooler 21 cools the semiconductor module 30 from the back surface 31b side.

[0032] The base 20 having the first cooler 21 may be constituted by a single member, or may be constituted by combining a plurality of members.

[0033] The base 20 may be provided alone or as part of a case that houses other elements of the power conversion device 4. As an example, the base 20 of the present embodiment is provided as the bottom wall of the case 22. The case 22 has an opening for housing other elements. The case 22 has a base 20 forming the bottom wall and side walls 23 that are continuous with the base 20 and define a housing space 22S together with the base 20. As an example, the case 22 of the present embodiment has a box shape with one side open. The case 22 has a substantially rectangular shape in a plan view in the Z direction. In the housing space 22S of the case 22, a semiconductor module 30, a second cooler 40, a capacitor 50, a circuit board 60, etc. are arranged.

[0034] On the side wall 23, an introduction pipe 24 for supplying refrigerant to the first cooler 21 and the second cooler 40 and a discharge pipe 25 for discharging refrigerant from the first cooler 21 and the second cooler 40 are attached. The introduction pipe 24 and the discharge pipe 25 are attached to, for example, a common side wall 23.

[0035] The power conversion device 4 may include a cover (lid), not shown, that closes the opening of the case 22. The case 22 and the cover may be referred to as a housing.

[0036] <semiconductor module> The semiconductor module 30 constitutes the above-described upper and lower arm circuits 10, that is, the inverter 5. The power conversion device 4 of the present embodiment includes three semiconductor modules 30. One semiconductor module 30 provides one series circuit 12, that is, an upper and lower arm circuit 10 for one phase. The plurality of semiconductor modules 30 includes a semiconductor module 30U that constitutes the upper and lower arm circuit 10U, a semiconductor module 30V that constitutes the upper and lower arm circuit 10V, and a semiconductor module 30W that constitutes the upper and lower arm circuit 10W.

[0037] All semiconductor modules 30 have a common structure with each other. Each semiconductor module 30 includes a main body 31 and external connection terminals 32 protruding from the main body 31. The main body 31 includes a semiconductor element 33, a sealing body 34, and the like.

[0038] As an example, the semiconductor element 33 of the present embodiment is formed by forming the above-described n-channel type MOSFET 13 on a semiconductor substrate made of SiC. The MOSFET 13 has a vertical structure such that the main current flows in the thickness direction of the semiconductor element 33 (semiconductor substrate). The semiconductor element 33 has main electrodes on both surfaces in its own thickness direction. Specifically, each of the semiconductor elements 33 has a drain electrode on one surface and a source electrode on the back surface.

[0039] The main current flows between the drain electrode and the source electrode. The semiconductor element 33 of the present embodiment includes two semiconductor elements 33H that provide the switching element on the high side of the series circuit 12 and two semiconductor elements 33L that provide the switching element on the low side of the series circuit 12. The semiconductor elements 33H and 33L are arranged side by side in the Y direction. The two semiconductor elements 33H are arranged side by side in the X direction. Similarly, the two semiconductor elements 33L are arranged side by side in the X direction.

[0040] The sealing body 34 seals a part of each of the semiconductor element 33 and the external connection terminal 32. The other part of each of the external connection terminals 32 protrudes outside the sealing body 34. The sealing body 34 is made of a resin such as an epoxy resin. The sealing body 34 has a substantially rectangular planar shape, for example. The sealing body 34 forms the outer contour of the main body 31.

[0041] The sealing body 34, that is, the main body 31, has a front surface 31a as a surface forming the outer contour and a back surface 31b that is the surface opposite to the front surface 31a in the Z direction. The front surface 31a and the back surface 31b are flat surfaces, for example. In addition, it has side surfaces 31c and 31d that are surfaces connecting the front surface 31a and the back surface 31b. The side surface 31c is the surface opposite to the side surface 31d in the Y direction.

[0042] The plurality of external connection terminals 32 includes main terminals 32P, 32N, 32O electrically connected to the main electrodes of the semiconductor element 33 and a signal terminal 32S. The main terminal 32P is electrically connected to the drain electrode of the semiconductor element 33H. The main terminal 32N is electrically connected to the source electrode of the semiconductor element 33L. The main terminal 32P may be referred to as a P terminal, a high-potential power supply terminal, a positive electrode terminal, etc. The main terminal 32N may be referred to as an N terminal, a low-potential power supply terminal, a negative electrode terminal, etc. The main terminals 32P, 32N are electrically connected to the capacitor 50, that is, the smoothing capacitor 6, via the relay P bus bar 110P and the relay N bus bar 110N. The main terminals 32P, 32N protrude externally from the side surface 31c of the main body 31. The protruding portions of the main terminals 32P, 32N are arranged side by side in the X direction.

[0043] The main terminal 32O is electrically connected to the connection point between the source electrode of the semiconductor element 33H and the drain electrode of the semiconductor element 33L, that is, the connection point (midpoint) of the series circuit 12. The main terminal 32O protrudes externally from the side surface 31d of the main body 31. The main terminal 32O may be referred to as an O terminal, an output terminal, an AC terminal, etc. The main terminal 32O is connected to the corresponding winding 3a of the motor generator 3 via, for example, a bus bar (not shown).

[0044] The signal terminal 32S protrudes from the side surface 31c of the main body 31.

[0045] The semiconductor module 30 described above is disposed on the first cooler 21 such that one surface 31a of the main body 31, that is, the surface on which the drain electrode 33D of the semiconductor element 33 is formed, faces one surface 20a of the base 20. A heat conduction member may be disposed between the semiconductor module 30 and the first cooler 21. In this embodiment as an example, a heat conduction member 220 is interposed between the semiconductor module 30 and the first cooler 21. The heat conduction member 220 transfers the heat of the semiconductor module 30, for example, the heat generated by the semiconductor element 33, to the first cooler 21. The heat conduction member 220 has electrical insulation properties. As an example, the heat conduction member 220 of this embodiment is heat conduction grease. Instead of heat conduction grease, heat conduction gel may be used. The heat conduction member 220 is sometimes referred to as TIM. TIM is an abbreviation for Thermal Interface Material.

[0046] As shown in FIG. 2, the three semiconductor modules 30 are arranged side by side in the X direction. That is, the plurality of semiconductor modules 30 are arranged side by side along the X direction.

[0047] <Second Cooler> The second cooler 40 is provided without diverting the base 20 (case 22). The second cooler 40 is disposed on the back surface 31b of the semiconductor module 30. The second cooler 40 is laminated and disposed on the main body 31 of the semiconductor module 30 on the side opposite to the first cooler 21 so as to face the surface on which the source electrode of the semiconductor element 33 is formed. The above-described heat conduction member 220 may be disposed between the second cooler 40 and the semiconductor module 30. The second cooler 40 cools the semiconductor module 30 from the side opposite to the first cooler 21 in the Z direction. The semiconductor module 30 can be cooled from both sides in the Z direction by the second cooler 40 and the first cooler 21.

[0048] The second cooler 40 has a flow path 41 inside thereof. Refrigerant 42 is supplied to the flow path 41 via the introduction pipe 24. The refrigerant 42 that has flowed through the flow path 41 is discharged outside the power conversion device 4 via the discharge pipe 25. The second cooler 40 is disposed in the accommodation space 22S of the case 22. The refrigerant 42 is common with the above-described refrigerant 212.

[0049] The second cooler 40 is connected to the first cooler 21 via connection pipes 45 and 46.

[0050] A part of the refrigerant supplied from the introduction pipe 24 flows through the flow path 211 as the refrigerant 212 and is discharged from the discharge pipe 25. The other part of the refrigerant is supplied to the flow path 41 through the flow paths of the flow path 211 and the connection pipe 45. The refrigerant 42 that has flowed through the flow path 41 flows into the flow path 211 through the flow path of the connection pipe 46 and is discharged from the discharge pipe 25.

[0051] <Capacitor> The capacitor 50 provides the above-described smoothing capacitor 6. The capacitor 50 includes, for example, a case (not shown) and capacitor elements housed in the case. In FIGS. 2 and 3, the capacitor 50 is illustrated in a simplified manner.

[0052] As an example, the capacitor element of the present embodiment is a film capacitor element. The capacitor element is formed by winding a film around, for example, the Z axis. The capacitor element has electrodes (not shown) on both end faces in the Z direction.

[0053] The capacitor 50 has a pair of capacitor busbars 51 that are electrically connected to the relay busbar 110. The pair of capacitor busbars 51 is composed of a capacitor P busbar 51P and a capacitor N busbar 51N. The capacitor P busbar 51P and the capacitor N busbar 51N each have a first capacitor busbar extension 511P, 511N and a second capacitor busbar extension 512P, 512N. Capacitor busbar connection portions 515P, 515N that are electrically connected to the relay busbar 110 are provided on the second capacitor busbar extensions 512P, 512N.

[0054] Hereinafter, the capacitor bus bar 51 is referred to as the C bus bar 51, and the capacitor P bus bar 51P and the capacitor N bus bar 51N are referred to as the CP bus bar 51P and the CN bus bar 51N, respectively. Also, the first capacitor bus bar extension parts 511P and 511N and the second capacitor bus bar extension parts 512P and 512N are referred to as the first C extension parts 511P and 511N and the second C extension parts 512P and 512N, respectively. Furthermore, the capacitor bus bar connection part is referred to as the C connection parts 515P and 515N.

[0055] The C bus bar 51 is a plate-shaped metal member. One end of the CP bus bar 51P is connected to the positive electrode side electrode of the capacitor 50. One end of the CN bus bar 51N is connected to the negative electrode side electrode of the capacitor 50. FIG. 4 is a plan view of the relay bus bar unit, and FIG. 5 is a cross-sectional view of the relay bus bar unit and the capacitor bus bar. FIG. 5 shows a cross-sectional view of the capacitor bus bar. As shown in FIG. 5, the first C extension parts 511P and 511N extend in a predetermined first extension direction (Z direction) and the plate surfaces face each other. The C bus bar extension parts 511P and 511N extend along the outer shape of the capacitor 50 in the height direction of the capacitor 50.

[0056] As shown in FIG. 9, the second C extension parts 512P and 512N bend from the first C extension parts 511P and 511N and extend in the second extension direction (Y direction) opposite to each other. The second C extension parts 512P and 512N are at the same position as each other in the first extension direction (Z direction) and bend in the second extension direction (Y direction). The extension direction of the second C extension part 512N extends along the outer shape of the capacitor 50. The second C extension part 512P extends toward the semiconductor module 30 side. The second C extension part 512P is electrically connected to the relay P bus bar 110P at the C connection part 515P. The second C extension part 512N is electrically connected to the relay N bus bar 110N at the C connection part 515N. Note that the second C extension parts 512P and 512N may extend in different directions from each other or in the same direction, other than being opposite to each other.

[0057] Between the CP bus bar 51P and the CN bus bar 51N, a capacitor insulating member 53 having electrical insulation is disposed. The capacitor insulating member 53 is a plate-shaped resin member. The capacitor insulating member 53 is disposed to ensure insulation between the CP bus bar 51P and the CN bus bar 51N. The capacitor insulating member 53 may hold the CP bus bar 51P and the CN bus bar 51N so that the CP bus bar 51P and the CN bus bar 51N have a predetermined positional relationship. The capacitor insulating member 53 may be insulating paper instead of being plate-shaped.

[0058] The capacitor 50 is disposed on one surface 20a of the base 20 constituting the first cooler 21. The capacitor 50 of the present embodiment is disposed in the accommodation space 22S of the case 22. The capacitor 50 is arranged side by side in the Y direction with respect to the semiconductor module 30. The capacitor 50 has a substantially rectangular planar shape with the X direction as the longitudinal direction in plan view.

[0059] <Circuit board> The circuit board 60 includes, although not shown, a wiring board in which wirings are disposed on an insulating base material such as resin, electronic components mounted on the wiring board, connectors, and the like. A circuit is configured by the mounted electronic components and the wirings. The drive circuit 7 described above is configured on the circuit board 60.

[0060] The circuit board 60 is disposed so as to overlap the semiconductor module 30 in a plan view in the Z direction. The circuit board 60 is disposed above the three semiconductor modules 30. The signal terminals 32S of the three semiconductor modules 30 are mounted on the circuit board 60. As an example, the circuit board 60 of the present embodiment is disposed in the accommodation space 22S of the case 22. The circuit board 60 is located above the second cooler 40.

[0061] <Relay bus bar unit> As shown in FIGS. 5 and 7, the relay bus bar 110 has first extending portions 111P and 111N that extend in a first bus bar extending direction (Y direction) which is a predetermined direction. The first extending portions 111P and 111N are plate-shaped, and their plate surfaces face each other in the Z direction which is the plate thickness direction. The relay bus bar 110 has second extending portions 112P and 112N. The second extending portions 112P and 112N bend from the ends of the first extending portions 111P and 111N and extend in a second bus bar extending direction (Z direction) which is a direction different from the first bus bar extending direction. The second extending portions 112P and 112N are plate-shaped, and their plate surfaces face each other in the Y direction which is the plate thickness direction. The relay bus bar 110 has connection portions 131, 132, 133, and 134 for electrically connecting the inverter and the capacitor.

[0062] As shown in FIGS. 6 and 9, the fixing member 120 is disposed between the relay bus bars 110 so as to be sandwiched by the relay bus bars 110. The fixing member 120 is a member for fixing the relay bus bar 110. The fixing member 120 has a first extending portion 121, a second extending portion 122, a first fixing portion 123, a second fixing portion 124, a fixing member through hole 127, an annular wall 126, and a guide portion 125. As shown in FIG. 7, the first extending portion 121 is disposed between the first extending portions 111P and 111N in the direction in which the first extending portions 111P and 111N face each other. The second extending portion 122 is disposed between the second extending portions 112P and 112N in the direction in which the second extending portions 112P and 112N face each other.

[0063] <Relay P bus bar> The relay P bus bar 110P is arranged below the relay N bus bar 110N in the Z direction as shown in FIGS. 6 and 7. The first extension portion 111P is arranged below the first extension portion 111N in the Z direction. As shown in FIG. 4, the first extension portion 111P is arranged above the capacitor 50 and the C bus bar 51 in the Z direction. That is, the first extension portion 111P, which is one of the bus bars, is arranged between the capacitor 50 and the first extension portion 111N, which is the other bus bar, in the direction in which the relay bus bars 110 face each other. The first extension portion 111P is shorter in length in the Y direction than the first extension portion 111N. The first extension portion 111P is covered by the first extension portion 111N from above in the Z direction.

[0064] A first connection portion 131 electrically connected to the CP bus bar 51P is provided on the first extension portion 111P of the relay P bus bar 110P. One first connection portion 131 may be provided, or a plurality of first connection portions 131 may be provided. As an example, two first connection portions 131 are provided apart from each other in the X direction. The first connection portions 131 are provided at the same position in the Y direction, but may be provided at different positions. By electrically connecting the first connection portion 131 and the C connection portion 515P, the relay P bus bar 110P and the CP bus bar 51P are electrically connected.

[0065] The method of electrically connecting the relay bus bar 110 and the inverter 5 or the smoothing capacitor 6 may be bolt fastening, soldering, resistance welding, laser welding, or the like. As an example, the first connection portion 131 and the CP bus bar 51P in the present embodiment are connected by laser welding. The areas of the plurality of first connection portions 131 may be equal or different. The first connection portion 131 has a rectangular shape and is elongated in the longitudinal direction (X direction) of the first extension portion 111P. The lengths of the plurality of first connection portions 131 in the longitudinal direction may be equal or different.

[0066] The first extension part 111P faces the second C extension part 512P in the plate thickness direction (Z direction). Also, the first extension part 111P and the second C extension part 512P extend in parallel in the same direction (Y direction) with respect to each other. Furthermore, the plate surfaces of the first extension part 111P and the second C extension part 512P face each other. Also, the first connection part 131 and the C connection part 515P are arranged so as to face each other.

[0067] As shown in FIG. 6, the second extension part 112P is provided with relay terminal parts 136P that bend from the lower end in the Z direction of the second extension part 112P and extend to the inverter 5. A plurality of relay terminal parts 136P are provided, and the relay terminal parts 136P are provided with third connection parts 133 that are electrically connected to the inverter 5. The relay terminal parts 136P are arranged above the main terminal 32P in the Z direction. The relay terminal parts 136P face the main terminal 32P in the plate thickness direction (Z direction). Also, the relay terminal parts 136P extend in parallel in the same direction (Y direction) with respect to the main terminal 32P. Furthermore, the relay terminal parts 136P are arranged so as to face the main terminal 32P in the Z direction. The third connection part 133 is electrically connected to the main terminal 32P. Here, as an example, they are connected by laser welding.

[0068] As shown in FIG. 4, the first extension part 111P has an adjacent part 113 adjacent to the first connection part 131 so as to surround the periphery of the first connection part 131. At least a part of the adjacent part 113 faces the first extension part 111N which is the other bus bar. The adjacent part 113 may be anywhere in the first extension part 111P as long as it surrounds the periphery of the first connection part 131. Also, the shape of the adjacent part 113 may be arbitrary. The adjacent part 113 may be the entire part of the first extension part 111P excluding the first connection part 131. Also, the adjacent part 113 may be from the part along the outer edge of the first connection part 131 to a part separated by a predetermined range (for example, several cm) in the first extension part 111P.

[0069] The adjacent part 113 is a part of the first extension part 111P. The adjacent part 113 includes the entire outer edge of the annular connection part. In this embodiment, only a part of the adjacent part 113 faces the first extension part 111N. As shown in FIG. 4, among the adjacent part 113, the part on the side of the second extension part 112N (the side of the relay terminal part 136N) in the Y direction with respect to the first connection part 131 faces the first extension part 111N. Among the adjacent part 113, the part adjacent to the first connection part 131 in the X direction faces the first extension part 111N.

[0070] As shown in FIG. 8, a plurality of through fixing holes 114P are provided in the second extension part 112P. The fixing holes 114P are provided at positions facing the second fixing part 124 in the second extension part 112P. The plurality of fixing holes 114P are provided at the same position in the Z direction. The fixing hole 114P and the second fixing part 124 are fixed by caulking, press-fitting, or the like. Thereby, the second extension part 112P and the fixing member 120 are fixed.

[0071] A plurality of desat terminals 135P protruding in the Z direction are provided in the first extension part 111P of the relay P bus bar 110P. The desat terminals 135P are used in the desat method, which is a method for determining overcurrent to the semiconductor module 30. Usually, the collector-emitter voltage of the semiconductor element 33 shows a low voltage in a saturated state when an appropriate current flows through the semiconductor module 30. However, when an excessive current flows through the semiconductor module 30, it becomes an unsaturated state and shows a voltage higher than the saturated state. In the desat method, the desat terminals 135P are used to detect the unsaturated voltage and determine whether an excessive current is flowing through the semiconductor module 30.

[0072] <Relay N bus bar> The relay N bus bar 110N is arranged above the relay P bus bar 110P in the Z direction as shown in FIGS. 6 and 7. The first extension 111N is arranged above the first extension 111P in the Z direction. As shown in FIG. 4, the first extension 111N is arranged above the capacitor 50 and the C bus bar 51 in the Z direction. That is, the first extension 111N, which is the other bus bar, is arranged on the opposite side of the capacitor 50 with respect to the first extension 111N, which is one of the bus bars, in the direction in which the relay bus bars 110 face each other.

[0073] The first extension 111N of the relay N bus bar 110N has a base 115a provided with a bus bar through hole 116 and a second connection portion 132 connected to the CN bus bar 51N. The first extension 111N of the relay N bus bar 110N is composed of a base 115a, a vertical portion 115b, and a horizontal portion 115c. The first extension 111N branches into two in the middle of extending in the Y direction and further extends in the Y direction. Also, a second connection portion 132 electrically connected to the CN bus bar 51N is provided on the first extension 111N.

[0074] The second connection portion 132 and the base are at different positions from each other in the direction (Z direction) in which the relay bus bars 110 face each other. In the present embodiment, as an example, the base 115a is arranged above the second connection portion 132 in the Z direction. The first extension 111N is bent in a crank shape from the second connection portion 132 to the base 115a so that the second connection portion 132 extends in parallel with the C connection portion 515N.

[0075] Among the first extension 111N, the portion from the upper end in the Z direction of the second extension 112N that bends and extends in the Y direction, branches into two, and further bends in the Z direction is referred to as the base 115a. The portion that bends from the end in the Y direction of the base 115a and extends downward in the Z direction is referred to as the vertical portion 115b. The portion that extends in the Y direction from the lower end in the Z direction of the vertical portion 115b is referred to as the horizontal portion 115c. A part of the base 115a, the vertical portion 115b, and the horizontal portion 115c form a crank shape. The base 115a faces the adjacent portion 113.

[0076] The second connection part 132 is provided on the horizontal part 115c. One second connection part 132 may be provided, or a plurality of second connection parts 132 may be provided. As an example, two second connection parts 132 are provided apart from each other in the X direction. The second connection parts 132 are respectively provided on the horizontal part 115c of the first extension part 111N branched into two. The second connection parts 132 are provided at the same position in the Y direction, but may be provided at different positions. By electrically connecting the second connection part 132 and the C connection part 515P, the relay N bus bar 110N and the CN bus bar 51N are electrically connected.

[0077] As an example, the second connection part 132 of the present embodiment and the CN bus bar 51N are connected by laser welding. The areas of the plurality of second connection parts 132 may be equal or different. The second connection part 132 has a rectangular shape and is elongated in the longitudinal direction (X direction) of the first extension part 111N. The lengths in the longitudinal direction of the plurality of second connection parts 132 may be equal or different.

[0078] The horizontal part 115c faces the second C extension part 512N in the plate thickness direction (Z direction). Also, the horizontal part 115c and the second C extension part 512N extend in parallel in the same direction (Y direction). Further, the plate surfaces of the horizontal part 115c and the second C extension part 512N face each other. Also, the second connection part 132 and the C connection part 515N are arranged to face each other.

[0079] The connection between the second connection part 132 and the C connection part 515N is made stronger than the connection between the first connection part 131 and the C connection part 515P. As an example, the connection is made stronger by making the area of the second connection part 132 larger than that of the first connection part 131. Alternatively, the length of the second connection part 132 may be made longer than that of the first connection part 131. Also, in the case of bolt fastening, the second connection part 132 may be made of a bolt with higher strength than the first connection part 131.

[0080] As shown in FIG. 6, the second extension portion 112N is provided with a relay terminal portion 136N that bends from the lower end of the second extension portion 112N in the Z direction and extends to the inverter 5. A plurality of relay terminal portions 136N are provided, and the relay terminal portions 136N are provided with fourth connection portions 134 that are electrically connected to the inverter 5. Among the plurality of relay terminal portions 136N, the two central ones have a larger area than the other relay terminal portions 136N. The relay terminal portion 136N is disposed above the main terminal 32N in the Z direction. The relay terminal portion 136N faces the main terminal 32N in the plate thickness direction (Z direction). Further, the relay terminal portion 136N extends in parallel with the main terminal 32N in the same direction (Y direction). Furthermore, the relay terminal portion 136N is disposed so as to face the main terminal 32N in the Z direction. The fourth connection portion 134 is electrically connected to the main terminal 32N. Here, as an example, they are connected by laser welding.

[0081] As shown in FIG. 4, the first connection portion 131 overlaps with the second connection portion 132 in the longitudinal direction (X direction) of the first extension portion. In the relay P bus bar 110P, which is one of the bus bars, the region of the shortest path connecting the first connection portion 131 and the third connection portion 133 is referred to as the first region R1. In the relay N bus bar 110N, which is the other bus bar, the region of the shortest path connecting the second connection portion 132 and the fourth connection portion 134 is referred to as the second region R2. FIG. 10 is a plan view of the relay bus bar unit 100 and the C bus bar 51. In FIG. 10, the relay N bus bar 110N and the CN bus bar 51N are shown integrally. Similarly, the relay P bus bar 110P and the CP bus bar 51P are shown integrally. As shown in FIG. 10, at least a part of the first region R1 and the second region R2 face each other.

[0082] The base portion 115a is provided with a penetrating bus bar through-hole 116. The bus bar through-hole 116 is provided at a position facing the first connection portion 131. The bus bar through-hole 116 is set to be larger than the first connection portion 131. The bus bar through-hole 116 is provided so that the relay bus bars 110 can be electrically connected to the capacitor 50 from the side of the other bus bar with the relay bus bars 110 arranged to face each other. As an example, the shape of the bus bar through-hole 116 is set to be annular, but it may be any other shape.

[0083] As shown in FIG. 8, a plurality of penetrating fixing holes 114N are provided in the first extension portion 111N. The fixing holes 114N are provided at positions facing the first fixing portion 123 at the base portion 115a of the first extension portion 111N. The plurality of fixing holes 114N are provided at the same positions as each other in the Y direction. The fixing holes 114N and the first fixing portion 123 are fixed by caulking, press-fitting, or the like. Thereby, the first extension portion 111N and the fixing member 120 are fixed.

[0084] A desat terminal 135N protruding in the Z direction is provided in the first extension portion 111N. The desat terminal 135N is provided at the end of the base portion 115a, but it may be provided at other positions. Also, a plurality of desat terminals 135N may be provided.

[0085] <Fixing member> The first extended portion 121 of the fixing member 120 extends in the first bus bar extension direction (Y direction). The first extended portion 121 faces and extends in parallel with the first extension portions 111P and 111N in the Z direction. The second extended portion 122 extends in the second bus bar extension direction (Z direction) from the end of the first extended portion 121. The second extended portion 122 faces and extends in parallel with the second extension portions 112P and 112N in the Y direction.

[0086] The first extension part 121 has a plurality of first fixing parts 123. The first fixing part 123 fixes the first extension parts 111P and 111N of the relay bus bar 110 to each other such that the first extension parts 111P and 111N face each other, and fixes the first extension part 111N, which is the other bus bar. The first fixing part 123 is a protrusion protruding in the Z direction. The first fixing part 123 is provided at a position facing the fixing hole 114N in the Z direction. The first fixing part 123 is inserted into the fixing hole 114N, and the first fixing part 123 is plastically deformed. Thereby, the first extension part 121 and the first extension part 111N are fixed, and the fixing member 120 and the relay N bus bar 110N are fixed.

[0087] The second extension part 122 has a plurality of second fixing parts 124. The second fixing part 124 fixes the second extension part 112P, which is one of the bus bars, such that the first extension parts 111P and 111N of the relay bus bar 110 face each other with a gap d1 therebetween. And the second fixing part 124 fixes the second extension part 112P, which is one of the bus bars, such that the first extension part 111P and the first extension part 121 face each other with a predetermined gap d1a therebetween. Thereby, the adjacent part 113 and the first extension part 121 face each other with the gap d1a therebetween.

[0088] The second fixing part 124 is a protrusion protruding in the Y direction from the second extension part 122. The second fixing part 124 is provided at a position facing the fixing hole 114P in the Y direction. The second fixing part 124 is inserted into the fixing hole 114P, and the second fixing part 124 is plastically deformed. Thereby, the second extension part 122 and the second extension part 112P are fixed, and the fixing member 120 and the relay P bus bar 110P are fixed.

[0089] As shown in FIG. 7, by the second fixing part 124, the second extension parts 112P and 112N are fixed with a predetermined gap d2 therebetween in the facing direction (Y direction). In the present embodiment, the second extension part 112P and the second extension part 122 are designed to be in contact with each other, but they do not have to be in contact. In the present embodiment, the second extension part 112N and the second extension part 122 are not in contact with each other, but they may be in contact. In the present embodiment, the gap d2 is substantially the same as the thickness of the second extension part.

[0090] The fixing member 120 fixes the second extending portion 112P, which is one of the bus bars, in a state where it can be elastically deformed in the direction (Z direction) facing the first connecting portion 131. Here, the direction facing the first connecting portion 131 is also understood as the direction perpendicular to the plate surface of the second extending portion 112P. Further, the direction facing the first connecting portion 131 may be understood as the direction in which the relay bus bars 110 face each other.

[0091] The fixing member 120 fixes the second extending portion 112P, which is one of the bus bars, with a gap d1a left between the first connecting portion 131 and the fixing member 120 in the direction (Z direction) facing the first connecting portion 131. In other words, the second extending portion 112P is fixed in a state where the adjacent portion 113 and the first extending portion 121 face each other with a gap d1a in the direction (Z direction) facing the first connecting portion 131. Due to this gap d1a, the first extending portion 111P can be elastically deformed in the Z direction. The interval d1 is set to be larger than the interval d2. Since the gap d1a is provided, the interval d1 is larger than the interval d2.

[0092] Among the relay P bus bars 110P, the second extending portion 112P is fixed to the fixing member 120, but the first extending portion 111P is not fixed to the fixing member 120. Therefore, the second extending portion 112P is in a state where it can move freely, that is, the first extending portion 111P is in a state of being cantilever-supported by the second fixing portion 124. As a result, the second extending portion 112P is in a state where it can move freely in the direction facing the first connecting portion 131.

[0093] A guide portion 125 is provided at the lower end portion in the Z direction of the second extending portion 122. The guide portion 125 extends vertically in the Y direction from the second extending portion and then bends and extends in the Z direction. A plurality of guide portions 125 may be provided, or only one guide portion 125 may be provided. The guide portion 125 is provided to facilitate the operation of assembling the relay N bus bar 110N and the fixing member 120. When assembling the relay N bus bar 110N and the fixing member 120, the relay N bus bar 110N is inserted into the guide portion 125 for positioning. Then, the operation of fixing the first fixing portion 123 and the fixing hole 114N is performed.

[0094] In the first extension part 121, a fixing member through-hole 127 that penetrates at a position facing the bus bar through-hole 116 is provided. In other words, the fixing member through-hole 127 is arranged at a position facing the first connection part 131. The fixing member through-hole 127 is provided so that the work of electrically connecting the relay P bus bar 110P to the capacitor 50 can be performed from the side of the relay N bus bar 110N through the bus bar through-hole 116 and the fixing member through-hole 127. The fixing member through-hole 127 is set to be smaller than the bus bar through-hole 116. The fixing member through-hole 127 is set to be annular, but it may have any other shape. The fixing member through-hole 127 has the same shape as the bus bar through-hole 116, but it may be different. For example, the bus bar through-hole 116 may be elliptical and the fixing member through-hole 127 may be circular.

[0095] In the first extension part 121, an annular wall 126 that extends in the Z direction from the outer edge of the fixing member through-hole 127 is provided. The annular wall 126 is a wall for increasing the creepage distance between the outer edge part of the bus bar through-hole 116 and the first extension part 111P which is one of the bus bars. The annular wall 126 is inserted into the bus bar through-hole 116 and has an annular shape along the bus bar through-hole 116. The annular wall 126 only needs to have a shape along the bus bar through-hole 116. The annular wall 126 extends above the first extension part 111N in the Z direction.

[0096] A fixing wall 128, which is a wall adjacent to the desat terminals 135N and 135P, is provided in the first extension part 121. As shown in FIG. 6, the fixing wall 128 extends in the Z direction from the first extension part 121 and is provided so as to be adjacent to the desat terminals 135N and 135P. The fixing wall 128 is provided to increase the creepage distance between the desat terminals 135N and 135P or between the desat terminal 135P and the first extension part 111N. The fixing wall 128 can ensure the insulation between the two.

[0097] <Summary of the embodiment> In this embodiment, an electrically insulating fixing member 120 fixes a relay bus bar 110, which is a pair of bus bars, with a gap d1 in the adjacent portion 113. As a result, since the gap between the pair of relay bus bars 110, which are bus bars, does not fluctuate, it is possible to suppress parasitic inductance in the adjacent portion 113 while ensuring insulation.

[0098] In this embodiment, the second extension portion 112P is fixed to one bus bar, and the first extension portion 111N is fixed to the other bus bar. For example, consider a case where the fixing member fixes the first extension portions 111P and 111N such that the second extension portions 112P and 112N of the pair of bus bars face each other. At this time, since neither of the second extension portions 112P and 112N of the pair of bus bars is fixed, the gap between the second extension portions 112P and 112N may become larger than expected, and there is a risk of an increase in parasitic inductance. Therefore, in this embodiment, the second extension portion 112P is fixed to one bus bar, and the first extension portion 111N is fixed to the other bus bar. Thereby, it is possible to suppress the gap (d1) between the first extension portions 111P and 111N and the gap (d2) between the second extension portions 112P and 112N from becoming larger than expected.

[0099] Here, consider a case where, after fixing the relay bus bar 110, which is a pair of bus bars, with the fixing member 120, the relay P bus bar 110P, which is one bus bar, and the CP bus bar 51P are connected. For example, assume that the relay P bus bar 110P, which is one bus bar, is fixed to the fixing member in a direction facing the first connection portion 131 in a non-elastically deformable manner. At this time, when connecting, the force applied to the relay P bus bar 110P may be directly transmitted to the fixing member 120, and the fixing member 120 may crack. In this embodiment, the relay P bus bar 110P, which is one bus bar, is fixed in an elastically deformable manner in a direction facing the first connection portion 131. Therefore, even if a force is applied to the relay P bus bar 110P when connecting, it is possible to suppress the fixing member 120 from cracking.

[0100] Furthermore, in the present embodiment, a relay P bus bar 110P, which is one of the bus bars, is fixed to be elastically deformable in a direction facing the first connection portion 131 by leaving a predetermined gap d1 from a fixing member 120 at the first connection portion 131. The relay P bus bar 110P, which is one of the bus bars, can move freely by the amount of the predetermined gap d1. Thereby, even when a force is applied to the relay P bus bar 110P when joining the relay P bus bar 110P, which is one of the bus bars, and the C connection portion 515P, it is possible to suppress the fixing member 120 from cracking.

[0101] Furthermore, in the present embodiment, relay bus bars 110, which are a pair of bus bars, face each other at an adjacent portion 113. A bus bar through-hole 116 is provided in a relay N bus bar 110N, which is the other bus bar facing the adjacent portion 113, at a position facing the first connection portion 131. Thereby, it becomes possible to electrically connect a relay P bus bar 110P, which is one of the bus bars, and a capacitor 50 at the first connection portion 131 through the bus bar through-hole 116.

[0102] In this embodiment, the relay N bus bar 110N, which is the other bus bar, and the fixing member 120 are provided with bus bar through holes 116 and fixing member through holes 127 that face each other. As a result, in a state where the relay bus bar 110 and the fixing member 120, which are a pair of bus bars, are arranged to face each other, the operation of electrically connecting the relay P bus bar 110P to the capacitor 50 can be performed from the side of the relay N bus bar 110N through both through holes. Here, when the fixing member through hole 127 is provided in the insulating fixing member 120, although the fixing member 120 is arranged between the relay bus bars 110, there is a risk that the opposing relay bus bars 110 may short-circuit around the fixing member through hole 127. Therefore, as in the present disclosure, by providing the annular wall 126 inserted into the bus bar through hole 116 in the fixing member 120, the creepage distance between the outer edge of the bus bar through hole 116 of the relay N bus bar 110N and the relay P bus bar 110P can be increased by the amount of the annular wall 126. Since this annular wall 126 has an annular shape along the bus bar through hole 116, insulation between the relay bus bars 110 is ensured even when the fixing member through hole 127 is provided, so that the distance between the relay bus bars can be narrowed. Therefore, it is possible to suppress parasitic inductance.

[0103] In this embodiment, the second C extension portions 512P and 512N are bent from the opposing first C extension portions 511P and 511N and extend in opposite directions. In the present disclosure, since the second C extension portions 512P and 512N having the C connection portions 515P and 515N extend in opposite directions, the second C extension portions 512P and 512N do not interfere with each other during connection. As a result, the connection work can be facilitated. Further, since the first C extension portions 511P and 511N face each other, parasitic inductance can be suppressed.

[0104] In this embodiment, the second C extension portions 512P and 512 are bent at the same position with respect to each other in the extending direction of the first C extension portions 511P and 511N. As a result, the power conversion device can be miniaturized in the extending direction as compared with the case where they are bent at different positions with respect to each other in the extending direction of the first C extension portions 511P and 511N.

[0105] In this embodiment, the first extension part 111N is bent into a crank shape having a part extending in parallel with the C connection part 515N. As a result, even if the bus bar through hole 116 is located above the C connection part 515N, the second connection part 132 and the C connection part 515P are in parallel contact with each other, so that the connection becomes easy.

[0106] In this embodiment, the relay P bus bar 110P is arranged between the capacitor 50 and the relay N bus bar 110N in the direction in which the relay bus bars 110 face each other. Therefore, the possibility that the first connection part 131 is peeled off by an external force is low. On the contrary, the relay N bus bar 110N is arranged on the opposite side of the capacitor 50 with respect to the relay P bus bar 110P in the direction in which the relay bus bars 110 face each other. For this reason, there is a possibility that the second connection part 132 is peeled off by an external force. In this embodiment, since the second connection part 132 has a larger area than the first connection part 131, the connection between the second connection part 132 and the capacitor 50 is stronger than that of the first connection part 131. Thereby, the turning up of the second connection part due to an external force can be suppressed.

[0107] According to this embodiment, at least a part of the current path flowing through the relay P bus bar 110P and the current path flowing through the relay N bus bar 110N face each other. Thereby, the parasitic inductance between the relay bus bars 110 can be suppressed.

[0108] According to this embodiment, the adjacent part 113 faces the relay N bus bar 110N among the relay bus bars 110. Thereby, it becomes possible to suppress the parasitic inductance in the adjacent part 113.

[0109] <Modification example> In the embodiment, among the adjacent portions 113, the portion on the side of the second extension portion 112N (the side of the relay terminal portion 136N) in the Y direction with respect to the first connection portion 131 faced the first extension portion 111N. Among the adjacent portions 113, the portion on the side of the second connection portion 132 (horizontal portion 115c) in the Y direction with respect to the first connection portion 131 may face the first extension portion 111N. Further, among the adjacent portions 113, both the portion on the side of the second extension portion 112N (the side of the relay terminal portion 136N) and the portion on the side of the second connection portion 132 (horizontal portion 115c) in the Y direction with respect to the first connection portion 131 may face the first extension portion 111N.

[0110] In the embodiment, the relay P bus bar 110P was used as one bus bar and the relay N bus bar 110N was used as the other bus bar, but they may be interchanged as appropriate.

[0111] The fixing member 120 may be a paper-like member such as insulating paper. Also, if electrical insulation between the relay P bus bar 110P and the relay N bus bar 110N is ensured, the fixing member 120 may not be provided.

[0112] The first fixing portion 123 may fix the second extension portion 112N of the other bus bar so that the first extension portions 111P and 111N of the pair of bus bars face each other. Also, the second fixing portion 124 may fix the first extension portion 111P of one bus bar so that the second extension portions 112P and 112N of the pair of bus bars face each other.

[0113] Both the first fixing portion 123 and the second fixing portion 124 may fix the same member. For example, both the first fixing portion 123 and the second fixing portion 124 may fix the first extension portion 111N. Also, both the first fixing portion 123 and the second fixing portion 124 may fix the second extension portion 112P. Also, only one of the first fixing portion 123 and the second fixing portion 124 may be provided.

[0114] The fixing member 120 may fix the second extension portion 112P, which is one bus bar, in a state where it is not elastically deformable in the direction facing the first connection portion 131.

[0115] The fixing member 120 does not necessarily need to leave a gap d1a between the first connecting portion 131 and the fixing member 120 in the direction facing the first connecting portion 131.

[0116] A bus bar through hole 116 is provided in the first extension portion 111N which is the other bus bar, and the welding of the first extension portion 111P and the second C extension portion 512P is performed from the side of the first extension portion 111N. On the contrary, the bus bar through hole 116 may be abolished and the above welding may be performed from the opposite side of the first extension portion 111N. Further, although the fixing member 120 had a fixing member through hole 127, it does not necessarily need to have it.

[0117] The number and positions where the fixing holes 114P and 114N are provided may be arbitrary. Further, the fixing holes 114P and 114N do not necessarily need to be provided.

[0118] The second C extension portions 512P and 512N may be bent from the first C extension portions 511P and 511N and extend in the same direction as each other. The second C extension portions 512P and 512N may be bent at different positions from each other in the first extension direction (Z direction).

[0119] The second connecting portion 132 and the base portion 115a may be at the same position as each other in the direction in which the relay bus bar 110 faces. Further, the first extension portion 111N which is the other bus bar does not necessarily need to be bent in a crank shape from the second connecting portion 132 to the base portion 115a. In that case, it is desirable that the second C extension portion 512N and the second connecting portion 132 be at the same position in the Z direction.

[0120] The connection of the first connecting portion 131 with the capacitor 50 may be made stronger than that of the second connecting portion 132. The second connecting portion 132 may have a smaller area than the first connecting portion 131. The length of the second connecting portion 132 may be shorter than that of the first connecting portion 131. Further, in the case of bolt fastening, the second connecting portion 132 may be made of a bolt having a lower strength than the first connecting portion 131.

[0121] The first region does not necessarily need to face the second region.

[0122] (Disclosure of Technical Ideas) This specification discloses a plurality of technical ideas described in a plurality of items listed below. Some items may be described in a multiple dependent form that alternatively cites a preceding item in subsequent items. Further, some items may be described in a multiple dependent form that cites another multiple dependent form item. The items described in these multiple dependent forms define a plurality of technical ideas.

[0123] (Technical Idea 1A) An inverter (5) for converting power, A capacitor (50) that supplies the inverter while smoothing the power supplied from a DC power source (2), And a pair of busbars (110) that electrically connect the inverter and the capacitor, One of the pair of busbars (110P) has a connection portion (131) electrically connected to the capacitor and an adjacent portion (113) adjacent to the connection portion so as to surround the periphery of the connection portion, At least a part of the adjacent portion faces the other busbar (110N) of the pair of busbars, a power conversion device.

[0124] (Technical Idea 2A) The power conversion device according to Technical Idea 1A, comprising an electrically insulating fixing member (120) for fixing the pair of busbars to face each other with a predetermined interval (d1) in the adjacent portion.

[0125] (Technical Idea 3A) The pair of busbars has a first extension portion (111P, 111N) extending in a first busbar extension direction that is a predetermined direction, and a second extension portion (112P, 112N) that bends from the first extension portion and extends in a second busbar extension direction that is different from the first busbar extension direction. The fixing member a first fixing portion (123) for fixing the first extending portion of the other bus bar so that the first extending portions of the pair of bus bars face each other and a second fixing portion (124) for fixing the second extending portion of the one bus bar so that the second extending portions of the pair of bus bars face each other, the power conversion device according to Technical Idea 2A.

[0126] (Technical Idea 4A) The fixing member fixes the one bus bar in a state where it can be elastically deformed in a direction facing the connection portion, the power conversion device according to Technical Idea 2A or 3A.

[0127] (Technical Idea 5A) With a gap (d1a) provided between the connection portion and the fixing member in the facing direction, the one bus bar is fixed to the fixing member, the power conversion device according to Technical Idea 4A.

[0128] (Technical Idea 6A) A bus bar through hole (116) penetrating at a position facing the connection portion is provided in the other bus bar, the power conversion device according to any one of Technical Ideas 1A to 5A.

[0129] (Technical Idea 1B) an inverter (5) for converting power a capacitor (50) for smoothing the power supplied from the DC power supply (2) and supplying it to the inverter a pair of bus bars (110) arranged opposite to each other for electrically connecting the inverter and the capacitor an insulating fixing member (120) disposed between the pair of bus bars for fixing the pair of bus bars One of the pair of bus bars (110P) has a connection portion (131) electrically connected to the capacitor The other bus bar (110N) of the pair of bus bars has a bus bar through hole (116) penetrating at a position facing the connection portion The fixed member has a fixed member through hole (127) that penetrates at a position facing the bus bar through hole, and an annular wall (126) that is inserted into the bus bar through hole and has an annular shape along the bus bar through hole, a power conversion device.

[0130] (Technical idea 2B) The capacitor has a pair of capacitor bus bars (51) that are electrically connected to the pair of bus bars, The pair of capacitor bus bars, A first capacitor bus bar extension portion (511P, 511N) that extends in a predetermined first extension direction and faces each other, and A second capacitor bus bar extension portion (512P, 512N) that bends from the first capacitor bus bar extension portion and extends in a second extension direction opposite to each other, and a capacitor bus bar connection portion (515P, 515N) that is electrically connected to the pair of bus bars is provided, the power conversion device according to Technical Idea 1B.

[0131] (Technical idea 3B) The second capacitor bus bar extension portion bends in the second extension direction at the same position in the first extension direction from the first capacitor bus bar extension portion, the power conversion device according to Technical Idea 2B.

[0132] (Technical idea 4B) Regarding the connection portion as a first connection portion, The other bus bar has a second connection portion (132) connected to the capacitor bus bar connection portion and a base portion (115a) provided with the bus bar through hole, The second connection portion and the base portion are at different positions from each other in the direction in which the pair of bus bars face each other, The other bus bar bends in a crank shape from the second connection portion to the base portion so that the second connection portion extends in parallel with the capacitor bus bar connection portion, the power conversion device according to Technical Idea 2B or 3B.

[0133] (Technical idea 5B) The one bus bar is disposed between the capacitor and the other bus bar in the direction in which the pair of bus bars face each other. The other bus bar is disposed on the opposite side of the capacitor with respect to the one bus bar in the direction in which the pair of bus bars face each other. The first connection portion and the second connection portion are electrically connected to the capacitor by being welded. The power conversion device according to Technical Idea 4B, wherein the second connection portion has a larger area than the first connection portion.

[0134] (Technical Idea 6B) The one bus bar has a third connection portion (133) that is electrically connected to the inverter. The other bus bar has a fourth connection portion (134) that is electrically connected to the inverter. Among the one bus bar, a region that forms a shortest path connecting the first connection portion and the third connection portion is defined as a first region (R1). Among the other bus bar, a region that forms a shortest path connecting the second connection portion and the fourth connection portion is defined as a second region (R2). The power conversion device according to Technical Idea 4B or 5B, wherein at least a part of the first region faces the second region.

[0135] (Technical Idea 7B) The one bus bar has an adjacent portion (113) adjacent to the connection portion so as to surround the periphery of the connection portion. The power conversion device according to any one of Technical Ideas 1B to 6B, wherein at least a part of the adjacent portion faces the other bus bar.

Explanation of Reference Numerals

[0136] 110 relay bus bar, 110P relay P bus bar, 110N relay N bus bar, 111N, 111P first extension part, 112N, 112P second extension part, 113 adjacent part, 116 bus bar through hole, 120 fixing member, 123 first fixing part, 124 second fixing part, 126 annular wall, 127 fixing member through hole, 131 connection part, 131 first connection part, 2 DC power supply, 5 inverter, 50 capacitor, d1 interval, d1a gap.

Claims

1. An inverter (5) that converts power, A capacitor (50) that smooths the power supplied from the DC power supply (2) and supplies it to the inverter, The inverter and the capacitor are electrically connected by a pair of busbars (110), One of the pair of busbars (110P) has a connection portion (131) that is electrically connected to the capacitor, and an adjacent portion (113) that surrounds the connection portion and is adjacent to the connection portion. At least a portion of the adjacent portion faces the other busbar (110N) of the pair of busbars, In the adjacent portion, an electrically insulating fixing member (120) is provided to fix the pair of busbars facing each other with a predetermined distance (d1) between them. The fixing member is a power conversion device that fixes one of the busbars in a state that is elastically deformable in a direction opposite to the connection portion.

2. The power conversion device according to claim 1, wherein one of the busbars is fixed to the fixing member with a gap (d1a) between the connecting portion and the fixing member in the opposing directions.

3. The power conversion device according to claim 1 or 2, wherein the other busbar is provided with a busbar through hole (116) that penetrates at a position opposite to the connection portion.

4. The power conversion device according to claim 3, wherein the busbar through-hole is larger than the connection portion.

5. The power conversion device according to claim 1 or 2, wherein the connecting portion is electrically connected to the capacitor by welding.

6. An inverter (5) for converting power, A capacitor (50) that smooths the power supplied from the DC power supply (2) and supplies it to the inverter, The inverter and the capacitor are electrically connected by a pair of busbars (110), One of the pair of busbars (110P) has a connection portion (131) that is electrically connected to the capacitor, and an adjacent portion (113) that surrounds the connection portion and is adjacent to the connection portion. At least a portion of the adjacent portion faces the other busbar (110N) of the pair of busbars, In the adjacent portion, an electrically insulating fixing member (120) is provided to fix the pair of busbars facing each other with a predetermined distance (d1) between them. The pair of busbars have a first extended portion (111P, 111N) that extends in a predetermined direction, which is a first busbar extending direction, and a second extended portion (112P, 112N) that bends from the first extended portion and extends in a second busbar extending direction, which is different from the first busbar extending direction. The aforementioned fixing member is A first fixing part (123) is provided to fix the first extended portion of the other busbar so that the first extended portions of the pair of busbars face each other, A power converter having a second fixing part (124) that fixes the second extension of one of the pair of busbars so that the second extensions of the pair of busbars face each other.

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