Power conversion device

Abstract

Provided is a power conversion device capable of suppressing leakage of high-frequency noise generated in a power module unit to a DC circuit, suppressing an increase in weight and an increase in manufacturing cost, and achieving high durability. A smoothing unit of a power conversion device has a plurality of smoothing capacitors (133), a positive electrode connection bus bar, and a negative electrode connection bus bar. The negative electrode connection bus bar has a negative electrode plate-shaped bus bar (135), negative electrode bus bars (132a, 132c, 132e), and a connection section (132 h). The negative electrode bus bars (132a, 132c, 132e) connect the extension section (135b) and the power module section. The negative electrode plate-shaped bus bar (135) is formed so as to be wider than the negative electrode bus bars (132a, 132c, 132e) and so as to be thinner than the negative electrode bus bars (132a, 132c, 132e) and the connection section (132 h).

Description

Technical Field

[0001] The invention relates to a power conversion device. Background Art

[0002] In recent years, the number of vehicles equipped with motors as driving sources for traveling has been increasing. Such vehicles are equipped with high-voltage batteries for supplying power to the motors. In addition, such vehicles are also equipped with power conversion devices for converting direct current supplied from the battery into alternating current.

[0003] Patent document 1 discloses a power conversion device. The power conversion device disclosed in Patent document 1 includes a power module unit and a smoothing unit. The smoothing unit is arranged on the side of the current path closer to the high voltage battery than the power module unit, and has a capacitor that reduces the pulsating voltage and smoothes the power. The power module has a plurality of semiconductor elements, and converts direct current into alternating current, or converts alternating current into direct current.

[0004] In the power conversion device disclosed in Patent Document 1, the smoothing unit has six bus bars extending outward from a capacitor housing unit housing a capacitor. The six bus bars connect the capacitor to the power module unit. Three of the six bus bars are connected to the positive terminal of the capacitor, and the remaining three bus bars are connected to the negative terminal of the capacitor. The six bus bars are configured in pairs, with a bus bar connected to the positive terminal of the capacitor and a bus bar connected to the negative terminal of the container.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2022-160271

[0008] Technical problem to be solved by the invention

[0009] However, the busbar of the smoothing part of the power conversion device is preferably wide and thin. This is because, from the perspective of suppressing the leakage of high-frequency noise generated by the power module part to the DC circuit, the busbar connecting the power module part and the capacitor is preferably low inductance, but the inductance can be reduced by increasing the width of the busbar.

[0010] However, if the width of the busbar is simply widened, it will lead to an increase in weight and a rise in manufacturing cost, so it is not preferred. In contrast, if the thickness of the busbar is reduced, although the weight can be suppressed, the inductance increases. Here, the inventors of the present application focus on the relationship between the weight and inductance of the busbar as follows. When the thickness of the busbar is reduced, the inductance increases, but because the sum of the width and thickness of the busbar is correlated with the inductance, in the case of a shape in which the width of the busbar is greater than the thickness of the plate, the increase in inductance relative to the proportion of thinning the plate thickness is less than the increase in inductance relative to the proportion of narrowing the width. On the other hand, the weight is reduced in the same proportion as the proportion of thinning the plate thickness. Therefore, the inventors of the present application believe that for a busbar having a smooth portion, by widening the width and thinning the wall, it is possible to achieve a reduction in inductance and suppress an increase in weight and a rise in manufacturing cost.

[0011] On the other hand, if the entire bus bar including the connection portion with the power module is thinned, the thinning may reduce rigidity and increase temperature at the connection portion with the power module and its surroundings, which may reduce durability. Summary of the invention

[0012] The present invention seeks to solve the above-mentioned problems, and an object thereof is to provide a power conversion device that can suppress leakage of high-frequency noise generated by a power module unit to a DC circuit, suppress an increase in weight and manufacturing cost, and achieve high durability.

[0013] Technical means for solving technical problems

[0014] A power conversion device according to one embodiment of the present invention includes a power module unit and a smoothing unit. The power module unit includes a plurality of power modules arranged along a first direction. The smoothing unit is adjacent to the power module unit on one side in a second direction intersecting the first direction and is electrically interposed between the power module unit and a DC circuit. The smoothing unit includes a smoothing capacitor, a positive-side connecting bus bar, and a negative-side connecting bus bar. The smoothing capacitor includes a positive-side terminal and a negative-side terminal. The positive-side connecting bus bar connects the positive-side terminal to the power module unit, and the negative-side connecting bus bar connects the negative-side terminal to the power module unit.

[0015] In the power conversion device of this embodiment, the connection busbar of one of the positive side connection busbar and the negative side connection busbar has a first busbar and a second busbar. The first busbar is plate-shaped, connected to the corresponding polarity terminal of the positive side terminal and the negative side terminal on the side corresponding to the polarity of the connection busbar, and has a terminal joint portion and an extension portion, the terminal joint portion is arranged along the corresponding polarity terminal, the extension portion is continuous with the terminal joint portion and extends to one side of the power module portion, and is arranged along the side of the smoothing capacitor. The second busbar connects the extension portion of the first busbar and the power module portion, and has a base portion and a connecting piece portion, the base portion extends in the first direction and is joined to the surface of the extension portion of the first busbar on the power module portion side, the connecting piece portion extends from the base portion to the power module portion side, and connects the base portion to the power module terminal of the power module portion.

[0016] In the power conversion device of this embodiment, the terminal joint portion and the extension portion of the first bus bar are formed to be wider in the first direction than the connecting piece portion of the second bus bar, and to be thinner than the base portion and the connecting piece portion of the second bus bar.

[0017] In the power conversion device of the above-mentioned embodiment, the terminal joint portion and the extension portion of the first bus bar are formed to have a width wider than the connection piece portion of the second bus bar. Therefore, the inductance can be reduced compared to the case where the width of the terminal joint portion and the extension portion of the first bus bar is made the same as or narrower than the connection piece portion of the second bus bar.

[0018] In addition, in the power conversion device of the above-mentioned embodiment, the terminal joint portion and the extension portion of the first bus bar are formed to have a plate thickness thinner than the base portion and the connecting piece portion of the second bus bar. Therefore, compared with a case where the plate thickness of the terminal joint portion and the extension portion of the first bus bar is the same as or thicker than the base portion and the connecting piece portion of the second bus bar, it is possible to reduce the inductance while suppressing an increase in weight and an increase in manufacturing cost.

[0019] In addition, in the power conversion device of the above-mentioned manner, the plate thickness of the connecting piece portion of the second busbar is formed to be thicker than the terminal joint portion and the extended portion of the first busbar. Therefore, compared with the case where the plate thickness of the connecting piece portion of the second busbar is the same as or thinner than the terminal joint portion and the extended portion of the first busbar, by ensuring a large cross-sectional area, it is possible to suppress a decrease in rigidity and a decrease in durability due to a temperature increase in the connection portion with the power module terminal and its surroundings.

[0020] Furthermore, in the power conversion device of the above-mentioned aspect, the base of the second bus bar having a plate thickness thicker than the terminal joint portion and the extension portion of the first bus bar is joined to the extension portion of the first bus bar, so that the rigidity of the extension portion of the first bus bar is reinforced by the base of the second bus bar. Therefore, in the power conversion device of the above-mentioned aspect, it is possible to ensure high rigidity of the above-mentioned one connection bus bar while reducing inductance and suppressing weight increase and manufacturing cost increase.

[0021] In the power conversion device of the above-mentioned embodiment, the smoothing portion may also include other structural components different from the smoothing capacitor, the positive-side connecting bus bar, and the negative-side connecting bus bar, and the other structural components are arranged adjacent to one side of the first bus bar in the first direction. In addition, the terminal joint portion and the extension portion in the first bus bar may be arranged offset to the other side in the first direction to avoid the other structural components. Furthermore, the base of the second bus bar may be arranged in a state protruding toward the one side in the first direction compared to the side edge of the one side in the first bus bar.

[0022] In the above-mentioned power conversion device, by arranging the above-mentioned other structural components adjacent to the first bus bar on one side of the first direction, although the terminal joint portion and the extension portion of the first bus bar are offset to the other side in the first direction, the base of the second bus bar protrudes to one side of the first direction relative to the side edge of the first bus bar. Therefore, even if the first bus bar is offset, the connection between the power module terminal and the connecting piece portion can be achieved while ensuring a high degree of design freedom.

[0023] In the power conversion device of the above-mentioned manner, it is also possible that, when the direction intersecting both the first direction and the second direction is set as a third direction, the extension portion of the first bus bar is formed to extend toward one side in the third direction with the end edge portion on the power module portion side in the terminal joint portion as a base end. In this case, it is also possible that the power conversion device further includes a cooling portion, which is thermally coupled to the first bus bar in the smooth portion and is arranged on the other side in the third direction relative to the terminal joint portion of the first bus bar. In addition, it is also possible that the base of the second bus bar is connected to the connecting piece portion at the end edge portion on the one side in the third direction.

[0024] In the power conversion device of the above-mentioned manner, the base of the second busbar is connected to the connecting piece at the end edge of the above-mentioned one side in the third direction, and is also present at a position closer to the other side in the third direction than the connecting portion. Therefore, the joining area between the base of the second busbar and the extension of the first busbar is the area from the connection position with the connecting piece to the above-mentioned other side in the third direction. Moreover, the cooling portion is arranged on the above-mentioned other side in the third direction relative to the terminal joint portion of the first busbar, so the heat of the connecting piece of the second busbar is absorbed by the cooling portion via the base and the extension and terminal joint portion of the first busbar. Therefore, in the power conversion device of the above-mentioned manner, there is an advantage in achieving high durability of the second busbar.

[0025] In the power conversion device of the above-mentioned embodiment, the connection busbar of the other of the positive-side connection busbar and the negative-side connection busbar may include a third busbar and a fourth busbar. The third busbar may be plate-shaped and connected to the corresponding polarity terminal of the positive-side terminal and the negative-side terminal on the side corresponding to the connection busbar, and the third busbar may include a terminal joint portion and an extension portion, the terminal joint portion is arranged along the corresponding polarity terminal, the extension portion is continuous with the terminal joint portion and extends to one side of the power module portion, and is arranged along the side surface of the smoothing capacitor. In addition, the fourth busbar may connect the extension portion of the third busbar with the power module portion, and the fourth busbar may include a base portion and a connecting piece portion, the base portion extends along the first direction and is joined to the surface of the extension portion on the power module portion side, the connecting piece portion extends from the base portion to the power module portion side, and is connected between the base portion and the power module terminal of the power module portion.

[0026] In the power conversion device of this embodiment, the terminal joint portion and the extension portion of the third bus bar may be formed to be wider in the first direction than the connecting piece portion of the fourth bus bar, and to be thinner in thickness than the base and the connecting piece portion of the fourth bus bar.

[0027] In the power conversion device of the above-mentioned embodiment, the terminal joint portion and the extension portion of the third bus bar are also formed to be wider than the connection piece portion of the fourth bus bar. Therefore, the inductance can be reduced compared with the case where the width of the terminal joint portion and the extension portion of the third bus bar is the same as or narrower than the connection piece portion of the fourth bus bar.

[0028] In addition, in the power conversion device of the above-mentioned embodiment, the terminal joint portion and the extension portion of the third bus bar are also formed to have a plate thickness thinner than the base portion and the connecting piece portion of the fourth bus bar. Therefore, compared with the case where the plate thickness of the terminal joint portion and the extension portion of the third bus bar is the same as or thicker than the base portion and the connecting piece portion of the fourth bus bar, it is possible to reduce the inductance while suppressing an increase in weight and an increase in manufacturing cost.

[0029] In addition, in the power conversion device of the above-mentioned manner, the plate thickness of the connecting piece portion of the fourth busbar is formed to be thicker than the terminal joint portion and the extended portion of the third busbar. Therefore, compared with the case where the plate thickness of the connecting piece portion of the fourth busbar is the same as or thinner than the terminal joint portion and the extended portion of the third busbar, by ensuring a large cross-sectional area, it is possible to suppress a decrease in rigidity and a decrease in durability due to a temperature increase in the connection portion with the power module terminal and its surroundings.

[0030] Furthermore, in the power conversion device of the above-mentioned aspect, the base of the fourth bus bar, which is thicker than the terminal joint portion and the extension portion of the third bus bar, is joined to the extension portion of the third bus bar, so that the rigidity of the extension portion of the third bus bar is reinforced by the base of the fourth bus bar. Thus, in the power conversion device of the above-mentioned aspect, the high rigidity of the above-mentioned one connection bus bar can be ensured while reducing the inductance and suppressing the increase in weight and the increase in manufacturing cost.

[0031] In the power conversion device of the above aspect, the extension portion of the first bus bar and the extension portion of the third bus bar may overlap each other in a non-contact state.

[0032] In the power conversion device of the above-mentioned manner, the extended portion of the first bus bar overlaps with the extended portion of the third bus bar in a non-contact state. Therefore, compared with the case where the extended portion of the first bus bar and the extended portion of the third bus bar are separately configured, the strength of the portion where the extended portions overlap can be improved.

[0033] In addition, in the portion where the extension of the first bus bar overlaps with the extension of the third bus bar, the main surfaces of the positive-side connecting bus bar and the negative-side bus bar face each other in a non-contact state, and parasitic capacitance is generated in this portion. As a result, in the power conversion device of the above-mentioned method, high-frequency noise generated in the power module part can be returned to the power module part side through the smoothing part, which has an advantage in suppressing the leakage of high-frequency noise to the DC circuit.

[0034] The power conversion device of the above aspect may further include a noise removing unit that is disposed between the smoothing unit and the DC circuit in the current path and is configured to include a ferrite core.

[0035] In the power conversion device of the above aspect, the noise removal unit is arranged between the smoothing unit and the DC circuit in the current path, and therefore it is more advantageous in suppressing leakage of high-frequency noise generated in the power module unit to the DC circuit.

[0036] Effects of the Invention

[0037] In the power conversion device of each of the above-described aspects, it is possible to suppress leakage of high-frequency noise generated by the power module unit to the DC circuit, suppress an increase in weight and manufacturing cost, and achieve high durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram showing the structure of a vehicle including the power conversion device according to the embodiment of the present invention.

[0039] Figure 2 It is a front view showing the arrangement of the power conversion device.

[0040] Figure 3 It is a perspective view showing the external appearance structure of the power conversion device.

[0041] Figure 4 It is a plan view showing the internal structure of the power conversion device.

[0042] Figure 5 Yes means Figure 4 Cross-sectional view of the VV line section.

[0043] Figure 6 It is a cross-sectional view showing the internal structure of the smoothing capacitor.

[0044] Figure 7 It is a perspective view showing a smooth portion with a portion omitted.

[0045] Figure 8 It is a plan view showing the positive electrode plate-shaped bus bar and the negative electrode plate-shaped bus bar, as well as the positive electrode bus bar and the negative electrode bus bar.

[0046] Fig. 9 It is a front view showing a positive electrode plate-shaped bus bar, a negative electrode plate-shaped bus bar, and a positive electrode bus bar and a negative electrode bus bar.

[0047] Fig.10 It is a cross-sectional view showing a positive electrode plate-shaped bus bar and a negative electrode plate-shaped bus bar, and a positive electrode bus bar and a negative electrode bus bar.

[0048] Fig.11 This is a block diagram showing the structure of a power conversion device.

[0049] Explanation of symbols

[0050] 100 Power conversion devices

[0051] 102a Refrigerant flow path (cooling unit)

[0052] 130 smooth part

[0053] 133 Smoothing capacitor

[0054] 132a, 132c, 132e Negative bus bar (connecting piece of the second bus bar)

[0055] 132b, 132d, 132f Positive busbars (connecting piece of the fourth busbar)

[0056] 132g Connecting part (base of the fourth bus bar)

[0057] 132h Connecting portion (base of second bus bar)

[0058] 134 Positive plate bus bar (third bus bar)

[0059] 135 negative plate bus bar (first bus bar)

[0060] 135c side edge

[0061] 137 Separator

[0062] 138Y capacitor (other structural parts)

[0063] 140 Power Module

[0064] 143IGBT (power module)

[0065] 144a, 144c, 144e negative power module terminals

[0066] 144b, 144d, 144f positive power module terminals

[0067] 1333 positive terminal

[0068] 1334 Negative terminal. DETAILED DESCRIPTION

[0069] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the embodiments described below are exemplary embodiments of the present invention, and the present invention is not limited to the embodiments described below except for its essential configuration.

[0070] 1. Structure of vehicle V

[0071] use Figure 1The structure of a vehicle V equipped with the power conversion device 100 according to the embodiment of the present invention will be described. In addition, hereinafter, the front-rear direction of the vehicle V is simply described as the "front-rear direction", the left-right direction (vehicle width direction) of the vehicle V is simply described as the "left-right direction", and the up-down direction of the vehicle V is simply described as the "up-down direction". In addition, the left-right direction in this embodiment corresponds to the "first direction", the front-rear direction corresponds to the "second direction", and the up-down direction corresponds to the "third direction".

[0072] like Figure 1 As shown, the vehicle V is equipped with a powertrain PT, a power conversion device 100 and a low-voltage battery 300 .

[0073] The vehicle V is a so-called hybrid electric vehicle (HEV), and is equipped with an engine E and a motor M that function as driving sources for traveling, that is, driving sources for the vehicle V (wheels W). The powertrain PT includes the engine E and the motor M. In addition to the engine E and the motor M, the powertrain PT also includes a transmission TM and a differential gear DF.

[0074] The motor M is a three-phase three-wire AC motor that rotates when supplied with three-phase AC power, and includes: an output shaft; a rotor having permanent magnets disposed around the output shaft; and a stator disposed on the outer periphery of the rotor and formed by coils wound around a plurality of teeth. The plurality of coils are composed of a U-phase coil, a V-phase coil, and a W-phase coil, and currents of different phases are supplied to the coils of each phase.

[0075] The transmission TM is connected to the motor M, and reduces the speed of rotation input from the motor M and outputs the rotation. The differential gear DF ​​transmits the rotation output from the transmission TM to the wheels W via the drive shaft S and the like.

[0076] In the present embodiment, as an example, a parallel hybrid electric vehicle is set as a vehicle V, and it is possible to travel using only the driving force of the motor M, travel using the driving force of both the motor M and the engine E, and travel using only the driving force of the engine E. In addition, the vehicle V can perform deceleration kinetic energy recovery, and the motor M generates electricity using the transmission force from the wheels W when the vehicle V is decelerating.

[0077] The high voltage battery 200 is a battery that transfers electric power between the motor M. When the motor M is driven as a driving source for traveling, the high voltage battery 200 supplies electric power to the motor M. On the other hand, when the motor M is driven as a generator during deceleration of the vehicle V, the high voltage battery 200 stores the electricity generated by the motor M.

[0078] The power conversion device 100 is an inverter device connected to a three-phase three-wire motor M, and converts the DC power from the high voltage battery 200 into AC power and supplies the power to the motor M. Specifically, the power conversion device 100 converts the DC power supplied from the high voltage battery 200 through the DC circuit into three-phase AC power and supplies the power to the motor M.

[0079] When the motor M is driven as a generator during deceleration of the vehicle V, the power conversion device 100 converts the AC power generated by the motor M into DC power and supplies the DC power to the high voltage battery 200 through the DC circuit.

[0080] The low voltage battery 300 is a battery for supplying electric power to electrical components provided in various parts of the vehicle V. The low voltage battery 300 is a battery having a lower rated voltage than the high voltage battery 200 .

[0081] The high voltage battery 200 is, for example, a lithium ion battery or a nickel metal hydride battery with a rated voltage of 24V or more, and the low voltage battery 300 is, for example, a lead battery or a lithium ion battery with a rated voltage of 12V or 24V.

[0082] In the present embodiment, the powertrain PT, the power conversion device 100 and the low voltage battery 300 are housed in a powertrain room R1 defined in the front portion of the vehicle V. The high voltage battery 200 is mounted under the floor of a vehicle room R2 defined behind the powertrain room R1.

[0083] Furthermore, the vehicle V is equipped with a PCM (Powertrain Control Module) 400 , which is a controller that comprehensively controls a powertrain PT including a motor M and an engine E.

[0084] 2. Configuration of the Power Converter 100

[0085] use Figure 2 The arrangement of the power conversion device 100 in the powertrain room R1 will be described. Figure 2 1 is a front view of the power conversion device 100 and its peripheral equipment as viewed from the front side of the vehicle V. Figure 2 The low voltage battery 300 is omitted in the figure.

[0086] like Figure 2 As shown, in the powertrain room R1, the engine E, the motor M, and the transmission TM are arranged in order from the right. The engine E has an engine lower portion 501 and an engine upper portion 502 arranged above the engine lower portion 501. The motor M is arranged adjacent to the engine lower portion 501 of the engine E on the left.

[0087] The motor M has a first motor housing 511 and a second motor housing 521 as housings. The first motor housing 511 is joined to the left side surface of the engine lower portion 501, and the second motor housing 521 is connected to the left side of the first motor housing 511 without a gap.

[0088] The transmission TM has an axle housing 531 as a housing. The axle housing 531 has a conical shape in which the cross-sectional dimension gradually decreases from the right to the left.

[0089] The power conversion device 100 is disposed in a portion extending from above the second motor housing 521 to above the axle housing 531 in the left-right direction of the vehicle V. The motor M and the power conversion device 100 are connected by coupling a connector (not shown) formed on the first motor housing 511 and a connector (not shown) of the power conversion device 100.

[0090] In addition, Figure 2 In a direction perpendicular to the paper, the front end portion of the power conversion device 100 (the end portion on the front side of the paper) is arranged on the same plane as the front end portion (the end portion on the front side of the paper) of any one of the first motor housing 511, the second motor housing 521 and the axle housing 531, or is set back rearward (inner side of the paper) compared to these front end portions.

[0091] 3. Structure of the Power Converter 100

[0092] use Figure 3 and Figure 4 The structure of the power conversion device 100 will be described.

[0093] like Figure 3 As shown, the power conversion device 100 includes a case 101 as a housing, which is composed of a case body 102 and a cover 103. The case body 102 has an opening at the upper side, and the cover 103 closes the opening of the case body 102.

[0094] Two refrigerant ports 105 and 106 are provided at the lower portion of the left side wall of the housing body 102. Refrigerant is introduced into the housing 101 from one of the refrigerant ports 105 and 106, and discharged from the other. The refrigerant introduced into the housing 101 absorbs heat from components of the power conversion device 100 including a smoothing portion described later.

[0095] Three PCM connectors 104 protrude upward from the front side portion of the cover 103. Figure 1 ) is connected to the power conversion device 100 via the PCM connector 104.

[0096] like Figure 4 As shown, the power conversion device 100 includes a housing 101 (in Figure 4 The DC connector unit 110, the noise removal unit 120, the smoothing unit 130, the power module unit 140, and the AC connector unit 150 are arranged in this order from the rear side to the front side in the front-rear direction of the vehicle V.

[0097] The DC connector 110 is a connector connected to a DC circuit including the high voltage battery 200, and a portion of the DC connector 110 protrudes to the rear of the housing body 102. The AC connector 150 is a connector connected to the motor M, and a portion of the AC connector 150 protrudes to the right of the housing body 102.

[0098] The noise removal unit 120 is configured to include a ferrite core, and is a functional unit for suppressing leakage of high-frequency noise into the DC circuit extending from the power conversion device 100 to the high-voltage battery 200. The noise removal unit 120 is provided between the smoothing unit 130 and the DC current loop in the current path, and more specifically, is inserted between the smoothing unit 130 and the DC connector unit 110 provided in the current path.

[0099] The smoothing unit 130 is a functional unit for smoothing direct current, and includes a smoothing capacitor (for example, a film capacitor). The smoothing unit 130 includes two bus bars 131 (positive bus bar 131a, negative bus bar 131b) for connecting to the DC connector unit 110 and six bus bars 132 (positive bus bars 132b, 132d, 132f, negative bus bars 132a, 132c, 132e) for connecting to the power module unit 140. In addition, the six bus bars 132 form pairs by adjacent positive bus bars 132b, 132d, 132f and negative bus bars 132a, 132c, 132f. That is, it is composed of three pairs of bus bars 132.

[0100] The negative electrode bus bars 132a, 132c, and 132e of the present embodiment correspond to the "connecting piece portion of the second bus bar", and the positive electrode bus bars 132b, 132d, and 132f correspond to the "connecting piece portion of the fourth bus bar".

[0101] The detailed structure of the smoothing portion 130 will be described later.

[0102] The power module unit 140 includes a module body 141 and a control circuit unit 142. The module body 141 includes three power modules 143. The control circuit unit 142 electrically controls the power modules 143 and the like in the module body 141. In the present embodiment, the power module 143 is composed of an IGBT (Insulated Gate Biopolar Transistor). In addition, the power module does not need to be limited to an IGBT, and may also be a known power module such as a MOSFET (Metal Oxide Semiconductor Fielded Effect Transistor).

[0103] The PCM connector 104 is connected to the control circuit unit 142. Then, the control unit formed in the control circuit unit 142 receives the PCM 400 (see Figure 1 ) command to control the power module 143 of the module body 141, changing the conversion amount of DC power and AC power, etc. Figure 4 In the figure, the detailed illustration of the control circuit unit 142 is omitted.

[0104] A portion of the AC connector 150 is inserted through the side wall of the housing body 102 and extends outward to the right side. Figure 2 ) on the motor side.

[0105] 4. Detailed Structure of Smooth Section 130

[0106] use Figures 5 to 11 , describing the detailed structure of the smoothing unit 130 in the power conversion device 100.

[0107] like Figure 5 , Figure 7 and Figure 8 As shown, in addition to the two bus bars 131 and the six bus bars 132, the smoothing portion 130 also includes: a plurality of (six as an example in the present embodiment) smoothing capacitors 133, a positive plate-shaped bus bar 134, a negative plate-shaped bus bar 135, a resin molded portion 136, a partition component 137 and a Y capacitor 138.

[0108] like Figure 6As shown in FIG. 1 , the smoothing capacitor 133 includes a positive electrode 1331, a negative electrode 1332, a positive electrode side terminal 1333, a negative electrode side terminal 1334, and a housing 1335. In addition, for the smoothing capacitor 133, it is not necessary to use a film capacitor, but it is preferable to use a film capacitor that is non-polar and has excellent voltage resistance, heat resistance, and durability. Here, in this embodiment, according to the connection relationship with the DC connector part 110, the terminal arranged at the upper part is used as the positive electrode side terminal 1333, and the terminal arranged at the lower part is used as the negative electrode side terminal 1334. In addition, the electrode body connected to the positive electrode side terminal 1333 is used as the positive electrode 1331, and the electrode body connected to the negative electrode side terminal 1334 is used as the negative electrode 1332.

[0109] The positive electrode 1331 includes an insulator (electrolyte) film 1331a and a metal film 1331b, and the metal film 1331b is formed on one main surface of the insulator film 1331a by evaporation. The negative electrode 1332 includes an insulator (electrolyte) film 1332a and a metal film 1332b, and the metal film 1332b is formed on one main surface of the insulator film 1332a by evaporation. The positive electrode side terminal 1333 and the negative electrode side terminal 1334 are terminals formed by spraying metal material on the resin film. As the resin film, for example, PP (polypropylene), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PPS (polyphenylene sulfide), etc. are used. As the sprayed metal, for example, Al (aluminum), Zn (zinc), etc. are used.

[0110] like Figure 7 and Figure 8 As shown, the positive plate-shaped bus bar 134 is a bus bar having a plate shape joined to the upper surface (positive terminal 1333) of the six smoothing capacitors 133 by welding. The negative plate-shaped bus bar 135 is a bus bar having a plate shape joined to the lower surface (negative terminal 1334) of the six smoothing capacitors 133 by welding.

[0111] In addition, each of the positive plate-shaped bus bar 134 and the negative plate-shaped bus bar 135 may be connected to the entire surface of the positive electrode side terminal 1333 and the negative electrode side terminal 1334 of each of the six smoothing capacitors 133 , or may be connected to a part of them.

[0112] In this embodiment, the positive plate-shaped bus bar is directly connected to the positive side terminal 1333 of the smoothing capacitor 133, and the negative plate-shaped bus bar 135 is directly connected to the negative side terminal 1334. However, by adopting such a structure, ESL (equivalent series inductance) and ESR (equivalent series resistance) can be reduced compared to the case of connection via a wire.

[0113] The negative electrode plate-shaped bus bar 135 in the present embodiment corresponds to the “first bus bar”, and the positive electrode plate-shaped bus bar 134 corresponds to the “third bus bar”.

[0114] like Figure 7 As shown, the positive plate-shaped bus bar 134 includes a terminal joint portion 134a, which covers the top of the six smoothing capacitors 133 and is connected to the positive terminal 1333 of each smoothing capacitor 133, and an extension portion 134b, which is continuous with the terminal joint portion 134a and is arranged along the side of the smoothing capacitor 133 on the power module unit 140 side (front side). The negative plate-shaped bus bar 135 includes a terminal joint portion 135a, which is arranged below the six smoothing capacitors 133 and is connected to the negative terminal 1334 of each smoothing capacitor 133, and an extension portion 135b, which is continuous with the terminal joint portion 135a and is arranged along the side of the smoothing capacitor 133 on the power module unit 140 side (front side).

[0115] like Figure 5 , Figure 7 as well as Fig.10 As shown, the extension 134b of the positive plate-like bus bar 134 and the extension 135b of the negative plate-like bus bar 135 overlap each other in a non-contact state on the power module part 140 side (front side). Then, a separator 137 is inserted between the extension 134b of the positive plate-like bus bar 134 and the extension 135b of the negative plate-like bus bar 135. The separator 137 is inserted in the entire area between the extension 134b of the positive plate-like bus bar 134 and the extension 135b of the negative plate-like bus bar 135. In addition, in the present embodiment, the separator 137 is formed by, for example, insulating paper such as synthetic fiber paper, or an insulating film such as PP (polypropylene).

[0116] like Figure 7 and Fig. 9 As shown, the positive bus bars 132b, 132d, and 132f are connected to the connecting portion 132g, and the connecting portion 132g is joined to the extension portion 134b of the positive plate-shaped bus bar 134. The connecting portion 132g is formed to extend in the left-right direction and is joined to the vicinity of the lower end portion of the extension portion 134b. In addition, the joining of the extension portion 134b and the connecting portion 132g is performed by, for example, resistance welding, laser welding, ultrasonic metal joining, brazing, or riveting.

[0117] The negative electrode bus bars 132a, 132c, and 132e are connected to the connecting portion 132h, which is joined to the extension portion 134b of the negative electrode plate-shaped bus bar 135. The connecting portion 132h is formed to extend in the left-right direction and is joined to the lower part of the extension portion 135b in the region overlapping with the extension portion 134b. In addition, the joining of the extension portion 135b and the connecting portion 132h is also performed by, for example, resistance welding, laser welding, ultrasonic metal joining, brazing, or riveting.

[0118] Here, if Fig. 9 As shown, the connection portion of the negative bus bars 132a, 132c, 132e to the connecting portion 132h is close to the upper edge of the connecting portion 132h. In other words, the connecting portion 132h is joined to the extension portion 135b at a portion below the negative bus bars 132a, 132c, 132e.

[0119] like Figure 5 As shown in FIG. 1 , a refrigerant flow path (cooling unit) 102a is provided in the housing body 102. The refrigerant flow path 102a is connected to the Figure 3 and Figure 4 The refrigerant ports 105 and 106 shown are continuous, and the smooth portion 130 is cooled. In addition, a heat transfer sheet 160 for improving cooling efficiency is inserted between the smooth portion 130 and the upper surface of the portion of the housing body 102 where the refrigerant flow path 102a is provided. In this embodiment, the heat transfer sheet 160 formed of a resin material such as silicone and acrylic is used. However, the resin material described above may be compounded with a filler such as silicon oxide, aluminum oxide, silicon nitride, or a heat transfer member such as graphite.

[0120] The negative bus bars 132a, 132c, 132e are thermally coupled to the refrigerant flowing in the refrigerant flow path 102a via the connecting portion 132h and the extension portion 135b. Figure 8 ) is effectively cooled via the connecting portion 132h.

[0121] As described above, the extension 134b of the positive plate-shaped bus bar 134 and the extension 135b of the negative plate-shaped bus bar 135 overlap with the separator 137. Thus, the positive bus bars 132b, 132d, 132f and the positive power module terminals 144b, 144d, 144f (see FIG. 144) of the power module unit 140 are connected. Figure 8 ) is also effectively cooled via the connecting portion 132g, the extension portion 134b and the partition member 137. In this regard, the partition member 137 preferably has a higher thermal conductivity than air.

[0122] In addition, the connection portion 132h of the present embodiment corresponds to the "base portion of the second bus bar", and the connection portion 132g corresponds to the "base portion of the fourth bus bar".

[0123] like Figure 8 As shown, the Y capacitor 138 provided in the smoothing portion 130 is arranged adjacent to the right side of the right side edge 135c of the negative plate-shaped bus bar 135. The Y capacitor 138 is, for example, a film capacitor or a ceramic capacitor, and is a functional portion for bypassing common mode noise to ground. Fig.11 As shown, the Y capacitors 138 are respectively inserted between the positive plate-shaped bus bar 134 and the negative plate-shaped bus bar 135 in the smoothing portion 130 and the case 101 .

[0124] like Figure 8 and Fig. 9 As shown in FIG. 1 , the negative plate-shaped bus bar 135 is offset to the left so that the terminal joint portion 135a and the extension portion 135b avoid the Y capacitor 138. With respect to such an offset arrangement of the negative plate-shaped bus bar 135, as shown in FIG. Fig. 9 As shown by arrow B, the connection portion 132 h protrudes to the right more than the right side edge 135 c of the negative electrode plate-shaped bus bar 135 .

[0125] like Figure 5 As shown, the smooth portion 130 further includes a resin molded portion 136 formed to cover the outside of the smooth portion 130 except for a portion of the top end side of the bus bar 131 and a portion of the top end side of the bus bar 132. The resin molded portion 136 prevents the intrusion of moisture, dust, etc. In this embodiment, as an example, the resin molded portion 136 is formed of an epoxy resin.

[0126] 5. Thickness of the positive plate-shaped bus bar 134 and the negative plate-shaped bus bar 135

[0127] use Fig.10 The thicknesses of the positive electrode plate-like bus bar 134 and the negative electrode plate-like bus bar 135 will be described.

[0128] As described above, the positive electrode plate-like bus bar 134 has the terminal joining portion 134 a and the extension portion 134 b which are continuous with each other, and the negative electrode plate-like bus bar 135 has the terminal joining portion 135 a and the extension portion 135 b which are continuous with each other.

[0129] In addition, as described above, the positive electrode bus bars 132b, 132d, and 132f (at Fig.10 In the figure, only the positive bus bar 132b is connected to the connecting portion 132g. In addition, in this embodiment, the positive bus bars 132b, 132d, and 132f are continuous with the connecting portion 132g and are formed integrally.

[0130] Negative bus bars 132a, 132c, 132e (at Fig.10 In the figure, only the negative bus bar 132c is connected to the connecting portion 132h. In addition, in the present embodiment, the negative bus bars 132a, 132c, 132e are continuous with the connecting portion 132h and are formed integrally.

[0131] The plate thickness of the extension portion 135b of the negative plate-like bus bar 135 is set to T1, and the plate thickness of the extension portion 134b of the positive plate-like bus bar 134 is set to T2. In addition, as described above, the terminal joint portion 135a is continuous with the extension portion 135b, and the terminal joint portion 134a is continuous with the extension portion 134b. Therefore, in this embodiment, the plate thickness of the terminal joint portion 135a of the negative plate-like bus bar 135 is also T1, and the plate thickness of the terminal joint portion 134a of the positive plate-like bus bar 134 is also T2.

[0132] On the other hand, the thickness of the connecting portion 132h is set to T3, the thickness of the connecting portion 132g is set to T4, the thickness of the negative electrode bus bars 132a, 132c, and 132e is set to T5, and the thickness of the positive electrode bus bars 132b, 132d, and 132f is set to T6.

[0133] In the power conversion device 100 of the present embodiment, the following relationship is satisfied.

[0134] T1<T3…(1)

[0135] T1<T5…(2)

[0136] T2<T4…(3)

[0137] T2<T6…(4)

[0138] That is, the positive plate-shaped bus bar 134 is formed to be thinner than the connecting portion 132g and the positive bus bars 132b, 132d, and 132f, and the negative plate-shaped bus bar 135 is formed to be thinner than the connecting portion 132h and the negative bus bars 132a, 132c, and 132e.

[0139] In addition, in the power conversion device 100 of the present embodiment, the width of the positive plate-shaped bus bar 134 and the negative plate-shaped bus bar 135, which is orthogonal to the flow direction of the current, is preferably a size of 40 times or more of the plate thickness, and more preferably 100 times or more. Since the sum of the width and the plate thickness of the bus bar is correlated with the inductance, the increase in parasitic inductance in the rate of change of the thinning of the plate thickness T1 of the negative plate-shaped bus bar 135 and the plate thickness T2 of the positive plate-shaped bus bar 134 becomes extremely small compared to the same rate of change in the bus bar with a square cross-section, and on the other hand, the weight can be reduced at the same ratio as the rate of change of the thinning of the plate thickness. That is, by widening the width of the two plate-shaped bus bars 134 and 135, the parasitic inductance can be suppressed, and the increase in parasitic inductance caused by thinning can be suppressed and the weight can be effectively reduced.

[0140] 6. Effect

[0141] In the power conversion device 100 of this embodiment, as Figures 7 to 9 As shown, the terminal joint portion 135a and the extension portion 135b of the negative electrode plate-shaped bus bar 135 are formed to have a width wider than the negative electrode bus bars 132a, 132c, and 132e. Therefore, compared with the case where the width of the terminal joint portion 135a and the extension portion 135b of the negative electrode plate-shaped bus bar 135 is made equal to or narrower than that of the negative electrode bus bars 132a, 132c, and 132e, the inductance can be reduced.

[0142] In addition, in the power conversion device 100, if Fig.10 As shown, the terminal joint portion 135a and the extension portion 135b of the negative electrode plate-shaped bus bar 135 are formed to have a plate thickness T1 thinner than the negative electrode bus bars 132a, 132c, 132e and the connecting portion 132h. Therefore, compared with the case where the plate thickness T1 of the terminal joint portion 135a and the extension portion 135b of the negative electrode plate-shaped bus bar 135 is the same as or thicker than that of the negative electrode bus bars 132a, 132c, 132e or the connecting portion 132h, it is possible to reduce inductance and suppress an increase in weight and an increase in manufacturing cost.

[0143] In addition, in the power conversion device 100, if Fig.10 As shown, the plate thickness T5 of the negative bus bars 132a, 132c, 132e is formed to be thicker than the terminal joint portion 135a and the extension portion 135b of the negative plate-shaped bus bar 135. Therefore, compared with the case where the plate thickness T5 of the negative bus bars 132a, 132c, 132e is made the same as or thinner than the terminal joint portion 135a or the extension portion 135b of the negative plate-shaped bus bar 135, by ensuring a large cross-sectional area, it is possible to suppress the reduction in rigidity and the reduction in durability caused by the increase in temperature at the connection portion with the negative power module terminals 144a, 144c, 144e and its surroundings.

[0144] In addition, in the power conversion device 100, if Figure 7 , Fig. 9 as well as Fig.10 As shown, the connecting portion 132h having a plate thickness T3 thicker than the terminal joint portion 135a and the extension portion 135b of the negative plate-like bus bar 135 is connected to the extension portion 135b of the negative plate-like bus bar 135, so that the rigidity of the extension portion 135b of the negative plate-like bus bar 135 is reinforced by the connecting portion 132h. As a result, in the power conversion device 100, it is possible to reduce the inductance and suppress the increase in weight and manufacturing cost while ensuring high rigidity of the negative plate-like bus bar 135, the connecting portion 132h, and the negative bus bars 132a, 132c, and 132e.

[0145] In addition, in the power conversion device 100, if Figure 8 and Fig. 9 As shown in FIG. 1 , by arranging the Y capacitor 138 adjacent to the negative plate-shaped bus bar 135 on the right side, although the terminal joint portion 135a and the extension portion 135b of the negative plate-shaped bus bar 135 are arranged offset to the left, the connecting portion 132h is formed so as to protrude to the right relative to the side edge 135c of the negative plate-shaped bus bar 135. Therefore, even if the negative plate-shaped bus bar 135 is as Figure 8 and Fig. 9 Even if the arrangement is offset to the left as shown, it is possible to achieve connection between the negative power module terminals 144 a , 144 c , 144 e and the connection piece while ensuring a high degree of design freedom.

[0146] In addition, in the power conversion device 100, if Figure 5 , Fig. 9 as well as Fig.10 As shown, the connecting portion 132h is connected to the negative bus bars 132a, 132c, and 132e at the upper end portion, and therefore, is joined to the extension portion 135b of the negative plate-shaped bus bar 135 from the connection position with the negative bus bars 132a, 132c, and 132e to the lower region (the width direction region of the connecting portion 132h). As a result, the heat of the negative bus bars 132a, 132c, and 132e is cooled by the heat absorption of the refrigerant flowing through the refrigerant flow path 102a via the connecting portion 132h, the extension portion 135b of the negative plate-shaped bus bar 135, and the terminal joint portion 135a. As a result, in the power conversion device 100, there is an advantage in achieving high durability of the negative bus bars 132a, 132c, 132e, the connecting portion 132h, and the like.

[0147] In addition, in the power conversion device 100, if Figures 7 to 9As shown, the terminal joint portion 134a and the extension portion 134b of the positive plate-shaped bus bar 134 are also formed to have a width wider than the positive bus bars 132b, 132d, and 132f. Therefore, compared with the case where the width of the terminal joint portion 134a and the extension portion 134b of the positive plate-shaped bus bar 134 is made the same as or narrower than that of the positive bus bars 132b, 132d, and 132f, the inductance can be reduced.

[0148] In addition, in the power conversion device 100, if Fig.10 As shown, the terminal joint portion 134a and the extension portion 134b of the positive plate-shaped bus bar 134 are also formed so that the plate thickness T2 is thinner than the positive bus bars 132b, 132d, 132f and the connecting portion 132g. Therefore, compared with the case where the plate thickness T2 of the terminal joint portion 134a and the extension portion 134b of the positive plate-shaped bus bar 134 is the same as or thicker than that of the positive bus bars 132b, 132d, 132f and the connecting portion 132g, it is possible to reduce the inductance while suppressing the increase in weight and the increase in manufacturing cost.

[0149] In addition, in the power conversion device 100, the plate thickness T6 of the positive bus bars 132b, 132d, and 132f is formed to be thicker than the terminal joint portion 134a and the extension portion 134b of the positive plate-shaped bus bar 134. Therefore, compared with the case where the plate thickness T6 of the positive bus bars 132b, 132d, and 132f is the same as or thinner than the terminal joint portion 134a and the extension portion 134b of the positive plate-shaped bus bar 134, by ensuring a large cross-sectional area, it is possible to suppress a decrease in rigidity and a decrease in durability due to a rise in temperature in the connection portion with the positive power module terminals 144b, 144d, and 144f and its surrounding areas.

[0150] In the power conversion device 100 of the above-mentioned embodiment, the connecting portion 132g having a plate thickness T4 thicker than the terminal joint portion 134a and the extension portion 134b of the positive plate-like bus bar 134 is joined to the extension portion 134b of the positive plate-like bus bar 134, and therefore, the rigidity of the extension portion 134b of the positive plate-like bus bar 134 is also reinforced by the joining of the connecting portion 132g. Thus, in the power conversion device 100, it is possible to ensure high rigidity of the positive plate-like bus bar 134, the connecting portion 132g, and the positive bus bars 132b, 132d, and 132f while reducing inductance and suppressing an increase in weight and manufacturing cost.

[0151] In addition, in the power conversion device 100, if Fig.10As shown, the extension portion 135b of the negative plate-like bus bar 135 overlaps with the extension portion 134b of the positive plate-like bus bar 134 in a non-contact state. Therefore, compared with the case where the extension portion 135b of the negative plate-like bus bar 135 and the extension portion 134b of the positive plate-like bus bar 134 are separately configured, the strength of the portion where the extension portions 134b and 135b overlap with each other can be improved.

[0152] In addition, parasitic capacitance is generated in the portion where the extension portion 135b of the negative plate-shaped bus bar 135 overlaps the extension portion 134b of the positive plate-shaped bus bar 134 in a non-contact state. As a result, in the power conversion device 100, high-frequency noise generated in the power module unit 140 can be returned to the power module unit 140 side through the smoothing unit 130, which is advantageous in suppressing leakage of high-frequency noise to the DC circuit.

[0153] In addition, there is also a small parasitic inductance in the busbars (extensions 134b, 135b, positive busbars 132b, 132d, 132f, negative busbars 132a, 132c, 132e) closer to the power module unit 140 than the smoothing capacitor 133. Since the rapid current change when the power module unit 140 is turned off is not smoothed by the smoothing capacitor 133 and is transmitted to the parasitic inductance closer to the power module unit 140 than the smoothing capacitor 133, it becomes a major factor that the surge voltage when the power module is turned off is large. Therefore, the parasitic inductance closer to the power module unit 140 than the smoothing capacitor 133 can be reduced by using the above-mentioned parasitic capacitance, and the surge voltage can be suppressed in combination with the reduction of inductance due to the widening of the width of the positive plate-shaped busbar 134 itself and the negative plate-shaped busbar 135 itself.

[0154] In addition, in the power conversion device 100, a noise removal unit 120 including a ferrite core is arranged between the smoothing unit 130 and the DC connector unit 110 in the current path, so it is more advantageous in suppressing the high-frequency noise generated by the power module unit 140 from leaking from the DC connector unit 110 to the external DC circuit.

[0155] As described above, in the power conversion device 100 of the present embodiment, it is possible to suppress leakage of high-frequency noise generated in the power module unit 140 to the DC circuit, suppress an increase in weight and manufacturing cost, and achieve high durability.

[0156] [Modifications]

[0157] In the above-mentioned embodiment, the plate thickness T2 of the terminal joint portion 134a and the extension portion 134b of the positive plate-like bus bar 134 is made thinner than the positive bus bars 132b, 132d, 132f and the connecting portion 132g, and the plate thickness T1 of the terminal joint portion 135a and the extension portion 135b of the negative plate-like bus bar 135 is made thinner than the negative bus bars 132a, 132c, 132e and the connecting portion 132h, but the present invention is not limited to this. For example, only the plate thickness T2 of the terminal joint portion 134a and the extension portion 134b of the positive plate-like bus bar 134 may be made thinner than the positive bus bars 132b, 132d, 132f and the connecting portion 132g, or only the plate thickness T1 of the terminal joint portion 135a and the extension portion 135b of the negative plate-like bus bar 135 may be made thinner than the negative bus bars 132a, 132c, 132e and the connecting portion 132h.

[0158] In addition, in the above embodiment, the positive bus bars 132b, 132d, 132f and the connecting portion 132g are integrated, and the negative bus bars 132a, 132c, 132e and the connecting portion 132h are integrated, but the present invention is not limited to this. For example, the positive bus bars 132b, 132d, 132f and the connecting portion 132g are connected, and the negative bus bars 132a, 132c, 132e and the connecting portion 132h are connected.

[0159] In addition, in the above embodiment, the terminal joint portion 134a of the positive plate-shaped bus bar 134 is arranged above the smoothing capacitor 133, and the terminal joint portion 135a of the negative plate-shaped bus bar 135 is arranged below the smoothing capacitor 133, but the present invention is not limited to this. For example, the terminal joint portion 134a of the positive plate-shaped bus bar 134 may be arranged below the smoothing capacitor 133, and the terminal joint portion 135a of the negative plate-shaped bus bar 135 may be arranged above the smoothing capacitor 133. Alternatively, the smoothing capacitor 133 may be arranged such that the positive terminal 1333 of the smoothing capacitor 133 is arranged on one side in the left-right direction and the negative terminal 1334 is arranged on the other side, and the terminal joint portion 134a of the positive plate-shaped bus bar 134 is arranged on the one side of the smoothing capacitor 133, and the terminal joint portion 135a of the negative plate-shaped bus bar 135 is arranged on the other side of the smoothing capacitor 133.

[0160] In addition, in the above embodiment, the Y capacitor 138 is used as an example of other structural components, but in the present invention, the smoothing portion 130 may also include other structural components (such as resistors, coils, etc.) other than the Y capacitor. In this case, as in the above embodiment, the following structure can be adopted: at least one of the positive plate-shaped bus bar 134 and the negative plate-shaped bus bar 135 is offset to one side in the left-right direction, and a part of the connecting portion protrudes outward from the side edge of the plate-shaped bus bar on the side where the offset configuration is performed.

[0161] In addition, in the above embodiment, the refrigerant flow path 102a is provided below the smooth portion 130 in the shell body 102, but the present invention is not limited to this for the formation position of the refrigerant flow path 102a. For example, the refrigerant flow path 102a can also be provided on the side wall of the shell body 102, or the refrigerant flow path can be provided on the cover 103.

[0162] In the above embodiment, an inverter device is used as an example of the power conversion device 100, but the present invention is not limited thereto. For example, the present invention can also be applied to a DC-DC converter or the like.

[0163] In addition, in the above-mentioned embodiment, the power conversion device 100 mounted on the vehicle V is taken as an example, but in the present invention, it can also be applied to a power conversion device used in industrial equipment, etc. In addition, as a vehicle, not only a hybrid electric vehicle (HEV) can be used, but also a battery electric vehicle (BEV) that does not have an engine as a driving source for traveling, etc. can be used.

[0164] Furthermore, in the above-described embodiment, a structure is adopted in which the resin molded portion 136 is provided on the outer portion of the smooth portion 130 . However, in the present invention, the smooth portion does not necessarily have to include the resin molded portion.

Claims

1. A power conversion device, characterized in that: have: a power module portion having a plurality of power modules arranged along a first direction; and a smoothing portion, the smoothing portion being arranged adjacent to the power module portion on one side in a second direction intersecting the first direction and electrically interposed between the power module portion and the DC circuit, and comprising a smoothing capacitor, a positive-side connecting bus bar, and a negative-side connecting bus bar, the smoothing capacitor having a positive-side terminal and a negative-side terminal, the positive-side connecting bus bar connecting the positive-side terminal and the power module portion, and the negative-side connecting bus bar connecting the negative-side terminal and the power module portion, The connecting bus bar of one of the positive-side connecting bus bar and the negative-side connecting bus bar comprises a first bus bar and a second bus bar, wherein the first bus bar is plate-shaped and connected to a corresponding polarity terminal of the positive-side terminal and the negative-side terminal on a side corresponding to the polarity of the connecting bus bar, and the second bus bar connects the first bus bar and the power module part, The first bus bar has a terminal joint portion and an extension portion, the terminal joint portion is arranged along the corresponding polarity terminal, the extension portion is continuous with the terminal joint portion and extends toward one side of the power module portion and is arranged along a side surface of the smoothing capacitor, The second bus bar has a base portion and a connecting piece portion, the base portion extending along the first direction and being joined to a surface of the extension portion of the first bus bar on the power module portion side, the connecting piece portion extending from the base portion toward the power module portion side and being connected between the base portion and a power module terminal of the power module portion, The terminal joint portion and the extension portion of the first bus bar are formed to be wider in the first direction than the connection piece portion of the second bus bar and to be thinner than the base portion and the connection piece portion of the second bus bar.

2. The power conversion device according to claim 1, characterized in that: The smoothing portion further includes another component different from the smoothing capacitor, the positive electrode side connection bus bar, and the negative electrode side connection bus bar, and the other component is arranged adjacent to one side of the first bus bar in the first direction. The terminal joint portion and the extension portion of the first bus bar are offset to the other side in the first direction to avoid the other structural components. The base portion of the second bus bar is disposed in a state of protruding toward the one side in the first direction relative to the one side edge of the first bus bar.

3. The power conversion device according to claim 1, characterized in that: When a direction intersecting both the first direction and the second direction is set as a third direction, The extension portion of the first bus bar is formed to extend toward one side in the third direction with the end edge portion of the terminal joint portion on the power module portion side as a base end. The power conversion device further includes a cooling portion that is thermally coupled to the first bus bar in the smooth portion and is disposed on the other side in the third direction relative to the terminal joint portion of the first bus bar. The end portion of the base portion of the second bus bar on the one side in the third direction is connected to the connection piece portion.

4. The power conversion device according to any one of claims 1 to 3, characterized in that: The other of the positive electrode side connection bus bar and the negative electrode side connection bus bar has: a third bus bar having a plate shape and connected to a corresponding polarity terminal of the positive-side terminal and the negative-side terminal on a side corresponding to the polarity of the connection bus bar, and having a terminal joint portion and an extension portion, the terminal joint portion being arranged along the corresponding polarity terminal, the extension portion being continuous with the terminal joint portion and extending toward one side of the power module portion, and being arranged along a side surface of the smoothing capacitor; as well as a fourth bus bar, the fourth bus bar connecting the extension of the third bus bar and the power module part, and the fourth bus bar having a base and a connecting piece, the base extending along the first direction and being engaged with a surface of the extension on the power module part side, the connecting piece extending from the base toward the power module part side and connected between the base and the power module terminal of the power module part, The terminal joint portion and the extension portion of the third bus bar are formed to be wider in the first direction than the connection piece portion of the fourth bus bar and to be thinner than the base portion and the connection piece portion of the fourth bus bar.

5. The power conversion device according to claim 4, characterized in that: The extended portion of the first bus bar and the extended portion of the third bus bar overlap each other in a non-contact state.

6. The power conversion device according to any one of claims 1 to 3, characterized in that: The device further includes a noise removing unit that is disposed between the smoothing unit and the DC circuit in the current path and includes a ferrite core.

7. The power conversion device according to claim 4, characterized in that: The widths of the first bus bar and the third bus bar in the first direction are respectively 40 times or more of the thicknesses of the first bus bar and the third bus bar.

8. The power conversion device according to claim 5, characterized in that: The extended portion of the first bus bar and the extended portion of the third bus bar overlap with each other via a partition member.

9. The power conversion device according to claim 8, characterized in that: The partition member has a higher thermal conductivity than air.

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