Power conversion device

Abstract

A power conversion device (20) comprises a DC bus bar (57) that electrically connects a DC power supply and a capacitor element (52). The DC bus bar (57) includes a connection section (571) and an extension section (572). The connection section (571) is connected to a bus bar (56), which is a wiring member for electrically connecting a semiconductor element (42) and the capacitor element (52). The extension section (572) extends in a Z direction from the connection section (571) toward a cooler (30), and is thermally connected to the cooler (30) via a heat conducting member (70) at a position between a body part (41) of a power module (40) and a body part (51) of a capacitor module (50).

Description

Power Conversion Device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-109803 filed in Japan on July 8, 2024, and the contents of the original application are incorporated by reference in their entirety.

[0002] TECHNICAL FIELD The disclosure herein relates to power conversion devices.

[0003] Patent Document 1 discloses a power conversion device. The contents of the prior art document are incorporated by reference as explanations of technical elements in this specification.

[0004] Japanese Patent Application Laid-Open No. 2021-125926

[0005] As the output of power conversion devices increases, the impact of heat generated by DC bus bars on capacitors also becomes greater. In Patent Document 1, an input bus bar (DC bus bar) electrically connected to a DC power source is disposed between a capacitor body including capacitor elements and a cooling member (cooler). Placing the capacitor body on the DC bus bar increases the size of the capacitor. Furthermore, although the DC bus bar can be cooled by cooling, the capacitor elements are located farther from the cooler, reducing the cooling effect of the capacitor elements. Further improvements are needed in power conversion devices in the above-mentioned respects and in other respects not mentioned.

[0006] An object of the present disclosure is to provide a power conversion device that can reduce the influence of heat on a capacitor element while suppressing an increase in size.

[0007] One disclosed aspect of a power conversion device includes: a cooler having one surface; a power module having a power main body including a semiconductor element and arranged on the one surface; a capacitor module having a capacitor main body including a capacitor element and arranged on the one surface; a wiring member extending in an arrangement direction of the power main body and the capacitor main body and electrically connecting the semiconductor element and the capacitor element; a DC bus bar electrically connecting the DC power supply and the capacitor element; and a heat conductive member comprising an electrically insulating material and interposed between the DC bus bar and the cooler, wherein the DC bus bar has a connection portion connected to the wiring member and an extension portion extending from the connection portion toward the cooler in a height direction perpendicular to the arrangement direction and thermally connected to the cooler via the heat conductive member between the power main body and the capacitor main body.

[0008] According to the disclosed power conversion device, the capacitor module is disposed on one surface of the cooler, thereby enabling effective cooling of the capacitor elements. The DC bus bar is thermally connected to the cooler via a thermally conductive member, thereby cooling the DC bus bar, thereby reducing the impact of heat from the DC bus bar on the capacitor elements. The DC bus bar is thermally connected to the cooler between the power body and the capacitor body in the arrangement direction. This prevents the device from increasing in size. As a result, a power conversion device can be provided that can reduce the impact of heat on the capacitor elements while preventing an increase in size.

[0009] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims are intended to exemplarily indicate the corresponding parts of the embodiments described below, and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings.

[0010] 2. It is a diagram showing a power conversion circuit and a drive system. It is a plan view showing an example of a power conversion device according to a first embodiment. It is a cross-sectional view taken along line III-III in FIG. 2. It is a cross-sectional view taken along line IV-IV in FIG. 2. It is a plan view showing a modified example. It is a cross-sectional view showing an example of a power conversion device according to a second embodiment. It is a cross-sectional view showing an example of a power conversion device according to a third embodiment. It is a cross-sectional view showing an example of a power conversion device according to a fourth embodiment. It is a diagram showing a resin molded body.

[0011] Hereinafter, several embodiments will be described with reference to the drawings. Note that in each embodiment, corresponding components are designated by the same reference numerals, and redundant description may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment previously described may be applied to the remaining portion of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0012] (First Embodiment) A capacitor module of this embodiment is applied to, for example, a mobile body using a rotating electric machine as a drive source. The mobile body is, for example, an electric vehicle such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), an electric flying object such as a drone or an electric vertical take-off and landing aircraft (eVTOL), a ship, construction machinery, or agricultural machinery. BEV is an abbreviation for Battery Electric Vehicle. HEV is an abbreviation for Hybrid Electric Vehicle. eVTOL is an abbreviation for electronic Vertical Take-Off and Landing aircraft. An example of application to a vehicle will be described below.

[0013] 1 shows an example of a vehicle drive system 1. The drive system 1 includes a DC power supply 2, a motor generator 3, and a power conversion circuit 4.

[0014] The DC power supply 2 is a DC voltage source composed of a rechargeable secondary battery. The secondary battery may be, for example, a lithium-ion battery or a nickel-metal hydride battery. The DC power supply 2 may convert AC to DC and output it. The motor generator 3 is a three-phase AC rotating electric machine. The motor generator 3 functions as a drive source for the vehicle, that is, an electric motor. The motor generator 3 functions as a generator during regeneration. The power conversion circuit 4 converts power between the DC power supply 2 and the motor generator 3.

[0015] 1 shows an example of a power conversion circuit 4. The power conversion circuit 4 shown in FIG.

[0016] The smoothing capacitor 5 mainly smoothes the DC voltage supplied from the DC power supply 2. The smoothing capacitor 5 is connected to a P line 7, which is a power supply line on the high potential side, and an N line 8, which is a power supply line on the low potential side. The P line 7 is connected to the positive electrode of the DC power supply 2, and the N line 8 is connected to the negative electrode of the DC power supply 2. The positive electrode of the smoothing capacitor 5 is connected to the P line 7 between the DC power supply 2 and the inverter 6. The negative electrode of the smoothing capacitor 5 is connected to the N line 8 between the DC power supply 2 and the inverter 6. The smoothing capacitor 5 is connected in parallel to the DC power supply 2.

[0017] The inverter 6 is a DC-AC conversion circuit. In accordance with switching control by the control circuit, the inverter 6 converts a DC voltage into a three-phase AC voltage and outputs it to the motor generator 3. This drives the motor generator 3 to generate a predetermined torque. During regenerative braking of the vehicle, the inverter 6 converts the three-phase AC voltage generated by the motor generator 3 in response to rotational force from the wheels into a DC voltage in accordance with switching control by the control circuit and outputs it to the P line 7. In this way, the inverter 6 performs bidirectional power conversion between the DC power source 2 and the motor generator 3.

[0018] The inverter 6 is configured with upper and lower arm circuits 9 for three phases. The upper and lower arm circuits 9 are sometimes referred to as legs. Each upper and lower arm circuit 9 has an upper arm 9H and a lower arm 9L. The upper arm 9H and the lower arm 9L are connected in series between the P line 7 and the N line 8, with the upper arm 9H on the P line 7 side. Hereinafter, the upper arm 9H and the lower arm 9L may be simply referred to as arms 9H and 9L.

[0019] The connection point between the upper arm 9H and the lower arm 9L, i.e., the midpoint of the upper and lower arm circuits 9, is connected to the corresponding phase winding 3a of the motor generator 3 via an output line 10. Of the upper and lower arm circuits 9, the U-phase upper and lower arm circuit 9U is connected to the U-phase winding 3a via the output line 10. The V-phase upper and lower arm circuit 9V is connected to the V-phase winding 3a via the output line 10. The W-phase upper and lower arm circuit 9W is connected to the W-phase winding 3a via the output line 10.

[0020] The number of switching elements constituting each arm 9H, 9L is not particularly limited. It may be one or more. In the illustrated upper arm 9H, three switching elements are connected in parallel. In the lower arm 9L, three switching elements are connected in parallel. In other words, each of the six arms 9H, 9L of the three-phase upper and lower arm circuit 9 is composed of three switching elements connected in parallel to each other.

[0021] The illustrated switching element is an n-channel MOSFET 11. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor. The three MOSFETs 11 on the high side connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage). The three MOSFETs 11 on the low side connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage).

[0022] A freewheeling diode 12 is connected in antiparallel to each MOSFET 11. The diode 12 may be a parasitic diode (body diode) or an external diode. In the upper arm 9H, the drain of the MOSFET 11 is connected to the P line 7. In the lower arm 9L, the source of the MOSFET 11 is connected to the N line 8. The source of the MOSFET 11 in the upper arm 9H and the drain of the MOSFET 11 in the lower arm 9L are connected to each other. The anode of the diode 12 is connected to the source of the corresponding MOSFET 11, and the cathode is connected to the drain.

[0023] The switching element is not limited to the MOSFET 11. For example, an IGBT may be used. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. In the case of an IGBT, a freewheeling diode is also connected in anti-parallel.

[0024] The power conversion circuit 4 may include a converter. The converter is a DC-DC conversion circuit configured to be able to convert DC voltage. The converter is provided between the DC power supply 2 and the smoothing capacitor 5. The converter is configured to include, for example, a reactor and the above-mentioned upper and lower arm circuits 9. This configuration allows for voltage step-up and step-down. The power conversion circuit 4 may also include a filter capacitor. The filter capacitor is provided between the DC power supply 2 and the converter.

[0025] The power conversion circuit 4 may include a snubber circuit. The snubber circuit is connected in parallel to the upper and lower arm circuits 9. The snubber circuit reduces the inductance of the upper and lower arm circuits 9. The snubber circuit absorbs a transient high voltage, known as a switching surge, that occurs when switching elements (MOSFETs 11) that constitute the upper and lower arm circuits 9. This enables the inverter 6 to perform high-speed switching.

[0026] The power conversion circuit 4 may include a drive circuit for the switching elements that constitute the inverter 6 and the like. The drive circuit supplies a drive voltage to the gate of the MOSFET 11 of the corresponding arm based on a drive command from the control circuit. The drive circuit drives the corresponding MOSFET 11, i.e., turns it on and off, by applying the drive voltage. The drive circuit is sometimes referred to as a driver.

[0027] The power conversion circuit 4 may include a control circuit for the switching element. The control circuit generates a drive command for operating the MOSFET 11 and outputs it to the drive circuit. The control circuit generates the drive command based on, for example, a torque request input from a host ECU (not shown) and signals detected by various sensors. ECU is an abbreviation for Electronic Control Unit.

[0028] The power conversion circuit 4 may include sensors. The sensors may include, for example, a current sensor 13, a rotation angle sensor, and a voltage sensor. The current sensor 13 detects the phase current flowing through the winding 3a of each phase. The rotation angle sensor detects the rotation angle of the rotor of the motor generator 3. The voltage sensor detects the voltage across the smoothing capacitor 5. The control circuit described above outputs a drive command, for example, a PWM signal, based on the signals detected by the sensors. The control circuit may include, for example, a processor and a memory. PWM is an abbreviation for Pulse Width Modulation.

[0029] <Power conversion device> Fig. 2 is a plan view showing an example of a power conversion device. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2. For convenience, capacitor elements are indicated by metal hatching in Figs. 3 and 4.

[0030] In the following, the mounting direction (stacking direction) of the semiconductor module and capacitor module relative to the cooler is referred to as the Z direction. The direction perpendicular to the Z direction is referred to as the X direction, and the direction perpendicular to both the X direction and the Z direction is referred to as the Y direction. The X direction, Y direction, and Z direction are mutually perpendicular. Unless otherwise specified, the shape viewed from the Z direction, in other words, the shape along the XY plane defined by the X direction and the Y direction, is referred to as the planar shape. The planar view from the Z direction may sometimes be simply referred to as the planar view.

[0031] 2 to 4 provides the above-described power conversion circuit 4. The power conversion device 20 includes a cooler 30, a power module 40, a capacitor module 50, and a current sensor 60.

[0032] The cooler 30 has one surface 30a, which is a mounting surface for other elements constituting the power conversion device 20. The cooler 30 is sometimes referred to as a support member. The cooler 30 may be at least a part of a housing that houses the other elements constituting the power conversion device 20, or may be provided separately from the housing. The cooler 30 is formed using a metal material such as aluminum. The cooler 30 may be formed from a single member, or may be formed by assembling multiple members.

[0033] The cooler 30 is another element constituting the power conversion device 20 and has the function of cooling elements arranged on the cooler 30. The cooler 30 may be, for example, a heat sink. The heat sink may have fins on the back side. The cooler 30 may have a flow path through which a refrigerant flows. The refrigerant may be, for example, a phase-change refrigerant such as water or ammonia, or a phase-non-change refrigerant such as an ethylene glycol-based refrigerant. The refrigerant may be, for example, LLC. LLC is an abbreviation for long life coolant.

[0034] The illustrated cooler 30 has a case 31 and a cover 32. The case 31 has a recess 33 and a flow path 34. A capacitor module 50 is disposed in the recess 33. The recess 33 is recessed relative to the surrounding area of ​​the recess 33 on one surface 30a of the cooler 30. The flow path 34 opens to the top surface of the case 31. A portion of the top surface of the case 31 forms the one surface 30a. A refrigerant inlet pipe and a refrigerant outlet pipe (not shown) are connected to the flow path 34. A refrigerant 35 flows through the flow path 34. The flow path 34 is arranged so as to overlap at least a portion of the power module 40 in a plan view. The flow path 34 is arranged so as to enclose, for example, a main body 41 of the power module 40.

[0035] The case 31 has a recess 36. The recess 36 is recessed from the surrounding area of ​​the recess 36 on one surface 30a of the cooler 30. At least a portion of the recess 36 is provided between the main body 41 of the power module 40 and the main body 51 of the capacitor module 50 in a plan view. The illustrated recess 36 extends in the X direction. A portion of the recess 36 is provided within the opposing area of ​​the main bodies 41, 51 in a plan view, and another portion is provided outside the opposing area of ​​the main bodies 41, 51.

[0036] The cover 32 closes the flow path 34. The cover 32 covers the opening of the case 31 and is fixed liquid-tightly to the surrounding area of ​​the opening. The cover 32 has fins that extend in the Z direction from the rear surface of the cover 32 and are disposed within the flow path 34. The fins are in contact with the refrigerant 35. The illustrated cover 32 has a plurality of pin-shaped fins. Although an example has been shown in which the cooler 30 includes the cover 32, this is not limiting. The power module 40 may also include a metal member that covers the opening of the flow path 34.

[0037] The cooler 30 and the elements (components) placed on the cooler 30 may be thermally connected via a bonding material such as solder, or via a thermally conductive member. The thermally conductive member may be referred to as TIM, GF, or the like. TIM is an abbreviation for Thermal Interface Material. GF is an abbreviation for Gap Filler.

[0038] The power modules 40 constitute the upper and lower arm circuits 9, i.e., the inverter 6. The power modules 40 are sometimes referred to as semiconductor modules, semiconductor devices, etc. The illustrated power conversion device 20 includes three power modules 40. The multiple power modules 40 include a power module 40U that constitutes the upper and lower arm circuit 9U, a power module 40V that constitutes the upper and lower arm circuit 9V, and a power module 40W that constitutes the upper and lower arm circuit 9W.

[0039] The plurality of power modules 40 have, for example, a common structure. The illustrated power module 40 includes a main body 41 and external connection terminals protruding from the main body 41. The main body 41 includes a semiconductor element 42, a sealing body 43, and the like.

[0040] The semiconductor element 42 is formed by forming a switching element on a semiconductor substrate made of silicon (Si) or a wide-bandgap semiconductor with a wider bandgap than silicon. The switching element has a vertical structure so that the main current flows in the thickness direction of the semiconductor substrate. Examples of wide-bandgap semiconductors include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), and diamond.

[0041] The illustrated semiconductor element 42 is formed by forming the above-described n-channel MOSFET 11 and diode 12 on a semiconductor substrate made of SiC. The MOSFET 11 has a vertical structure so that a main current flows in the thickness direction of the semiconductor element 42 (semiconductor substrate). The semiconductor element 42 has main electrodes (not shown) on both sides of the semiconductor element 42 in the thickness direction. The semiconductor element 42 has a source electrode on the front surface and a drain electrode on the back surface as main electrodes. The source electrode is formed on a portion of the front surface. The drain electrode is formed on almost the entire back surface.

[0042] The main current flows between the drain electrode and the source electrode. The semiconductor element 42 has a pad (not shown) that is a signal electrode on the surface where the source electrode is formed. The semiconductor elements 42 are arranged so that their thickness direction is approximately parallel to the Z direction. One power module 40 includes, as semiconductor elements 42, three semiconductor elements 42H that constitute the upper arm 9H and three semiconductor elements 42L that constitute the lower arm 9L. The three semiconductor elements 42H that constitute one arm are aligned in the X direction. Similarly, the three semiconductor elements 42L are aligned in the X direction. The semiconductor elements 42H and semiconductor elements 42L that constitute one arm are aligned in the Y direction.

[0043] The sealing body 43 seals some of the other elements that make up the power module 40. The remaining parts of the other elements are exposed outside the sealing body 43. The illustrated sealing body 43 seals the semiconductor element 42, some of the external connection terminals, etc. Other parts of the external connection terminals protrude outside the sealing body 43. The sealing body 43 is made of, for example, resin. The illustrated sealing body 43 is molded by transfer molding using epoxy resin. The sealing body 43 has a generally rectangular shape when viewed from above. The sealing body 43 forms the outer casing of the main body 41.

[0044] The sealing body 43 may be formed by potting. The sealing body 43 is filled into the accommodation space formed by the housing (not shown) and the cooler 30, and seals the semiconductor element 42 and the like placed in the accommodation space.

[0045] The external connection terminals are terminals for electrically connecting the power module 40 to an external device. The power module 40 includes at least signal terminals (not shown) as the external connection terminals. The signal terminals are electrically connected to pads of the semiconductor element 42. As illustrated, the power module 40 may include main terminals 44 as the external connection terminals, which are electrically connected to main electrodes of the semiconductor element 42. The main terminals 44 include a P terminal 44P, an N terminal 44N, and an output terminal 44A.

[0046] The P-terminal 44P is electrically connected to the drain electrode of the semiconductor element 42H. The N-terminal 44N is electrically connected to the source electrode of the semiconductor element 42L. The P-terminal 44P and the N-terminal 44N are at least a part of the wiring that electrically connects the semiconductor element 42 and the capacitor element 52. The output terminal 44A is electrically connected to the connection point (midpoint) between the source electrode of the semiconductor element 42H and the drain electrode of the semiconductor element 42L. The output terminal 44A is at least a part of the wiring that electrically connects the semiconductor element 42 and the motor-generator 3.

[0047] The number and arrangement of the P terminal 44P, the N terminal 44N, and the output terminal 44A are not particularly limited. The illustrated power module 40 includes one P terminal 44P, one N terminal 44N, and one output terminal 44A. The P terminal 44P and the N terminal 44N extend from the main body 41 toward the capacitor module 50. The P terminal 44P and the N terminal 44N protrude to the outside from the surface of the main body 41 that faces the capacitor module 50. The P terminal 44P and the N terminal 44N are aligned in the X direction. The output terminal 44A extends from the main body 41 toward the current sensor 60. The output terminal 44A protrudes to the outside from the side opposite the surface that faces the capacitor module 50.

[0048] In addition to the above-mentioned elements, the power module 40 also includes a wiring member (not shown). The wiring member provides a wiring function that electrically connects the main electrodes of the semiconductor element 42 to the main terminals 44. The wiring member provides a heat dissipation function that dissipates heat from the semiconductor element 42. The wiring member may be, for example, a substrate having a metal body disposed on one or both sides of an insulating base material, or may be a heat sink that is a metal member. The heat sink may be provided as part of the lead frame. The entire wiring member may be sealed by the sealing body 43, or a portion of the wiring member may be exposed from the sealing body 43. Exposing the wiring member can improve heat dissipation.

[0049] The power module 40 is disposed on one surface 30a of the cooler 30. As described above, the main body 41 of the power module 40 may be fixed to the cooler 30 via a bonding material, or may be thermally connected to the cooler 30 via a heat conductive member. As shown in FIG. 2 , the three power modules 40 are lined up in the X direction. The three power modules 40 are lined up in the order of power module 40U, power module 40V, and power module 40W. In addition, in the X direction, the side surfaces of adjacent power modules 40 face each other with a predetermined gap therebetween.

[0050] The capacitor module 50 provides the smoothing capacitor 5 described above. The capacitor module 50 includes a main body 51. The main body 51 is aligned in the Y direction with respect to the main body 41. The main body 51 includes a capacitor element 52 and a sealing body 53.

[0051] The capacitor element 52 is, for example, a film capacitor element. The capacitor element 52 has a generally rectangular shape in plan view. The capacitor element 52 has electrodes 55 on one surface and on the other surface. The electrodes 55 are sometimes referred to as metallikon electrodes. One of the electrodes 55 is a P-electrode 55P, and the other is an N-electrode 55N. The illustrated capacitor element 52 is formed, for example, by winding a film around an axis generally parallel to the Z direction. In the illustrated capacitor element 52, the one surface and the back surface are surfaces in the Z direction. In other words, the back surface is the surface opposite the one surface in the Z direction. The back surface is the lower surface facing the bottom wall of a bottomed cylindrical case 54 that houses the sealing body 53, and the one surface is the upper surface. The capacitor element 52 has a negative N-electrode 55N on one surface and a positive P-electrode 55P on the back surface.

[0052] The capacitor module 50 may include only one capacitor element 52 or multiple capacitor elements 52. In a configuration including multiple capacitor elements 52, the capacitor elements 52 are aligned in at least one direction perpendicular to the Z direction. The illustrated capacitor module 50 includes four capacitor elements 52. The capacitor elements 52 are aligned in the X direction.

[0053] The sealing body 53 is made of an electrically insulating resin material. The sealing body 53 is formed by potting, for example. The sealing body 53 seals the capacitor element 52. The sealing body 53 also seals a portion of the bus bar 56.

[0054] As illustrated, the main body 51 may have a case 54. The case 54 may be formed using a metal material such as aluminum, or may be formed using a resin material. The illustrated case 54 is made of resin. The case 54 has a cylindrical shape with a bottom. The case 54 has a bottom wall 541 and a side wall 542 continuous with the bottom wall 541. The case 54 is disposed on the one surface 30a of the cooler 30 so that the outer surface of the bottom wall 541 faces the one surface 30a of the cooler 30 in the Z direction, specifically the bottom surface of the recess 33. The illustrated bottom wall 541 has a generally rectangular planar shape with the X direction as the longitudinal direction. The side wall 542 has a generally rectangular planar ring shape.

[0055] The main body 51 has a bottom surface 51a, a top surface 51b, and a side surface 51c as surfaces that form the outer shell. In the illustrated capacitor module 50, the outer surface of the bottom wall 541 of the case 54 forms the bottom surface 51a. The outer surfaces of the side walls 542 form the side surfaces 51c. The top surface 51b is mainly composed of the sealing body 53. The outer surface of the bottom wall 541, i.e., the bottom surface 51a, forms a cooling surface 543 that is thermally connected to the cooler 30.

[0056] As illustrated, the capacitor module 50 may include bus bars 56. The bus bars 56 are metal plates made of a metal with good conductivity, such as Cu. The bus bars 56 include a P bus bar 56P and an N bus bar 56N. The P bus bar 56P is connected to a P electrode 55P of the capacitor element 52. The N bus bar 56N is connected to an N electrode 55N of the capacitor element 52. The P bus bar 56P and the N bus bar 56N are at least part of the wiring that electrically connects the semiconductor element 42 and the capacitor element 52. The P bus bar 56P and the N bus bar 56N each have an electrode connection portion 561, a terminal portion 562, and a coupling portion 563.

[0057] The electrode connection portions 561 are connection portions of the bus bars 56 that connect to the corresponding electrodes 55. The terminal portions 562 are portions of the bus bars 56 that protrude outside the sealing body 53. The terminal portions 562 are portions for connection to the power module 40. The terminal portion 562 of the P bus bar 56P is connected to the P terminal 44P of the power module 40. The terminal portion 562 of the N bus bar 56N is connected to the N terminal 44N. The coupling portions 563 are portions of the bus bars 56 that connect the electrode connection portions 561 and the terminal portions 562.

[0058] The electrode connection portion 561 and the coupling portion 563 are covered by the sealing body 53. The electrode connection portion 561 and the coupling portion 563 are disposed within the sealing body 53. The terminal portion 562 is disposed outside the sealing body 53. The capacitor module 50 includes a main body 51 including the electrode connection portion 561 and the coupling portion 563, and a terminal portion 562 protruding from the main body 51. The illustrated P bus bar 56P and N bus bar 56N are drawn out from the corresponding electrodes 55 in the Y direction toward the power module 40. The plate thickness direction of the electrode connection portion 561 is approximately parallel to the Z direction. The coupling portion 563 is continuous with the electrode connection portion 561 and includes a portion extending in the Y direction and a portion extending in the Z direction. The coupling portion 563 is approximately L-shaped in the YZ plane.

[0059] The terminal portion 562 extends from the connecting portion 563 toward the power module 40. The terminal portion 562 extends in the Y direction in a plan view. In order to reduce inductance, the P bus bar 56P and the N bus bar 56N are arranged to run parallel to each other and face each other over most of the entire length of the terminal portion 562. Note that an insulating member may be arranged between the terminal portion 562 of the P bus bar 56P and the terminal portion 562 of the N bus bar 56N.

[0060] The illustrated P bus bar 56P has a notch 564 in its terminal portion 562. The notch 564 is provided in a position that overlaps with the terminal portion 562 of the N bus bar 56N and the connection portion 571 of the DC bus bar 57N in a plan view. By providing the notch 564, the height of the terminal portion 562 of the P bus bar 56P is partially lowered, so that the terminal portion 562 of the N bus bar 56N and the connection portion 571 of the DC bus bar 57N do not need to be routed around the terminal portion 562 of the P bus bar 56P.

[0061] The illustrated capacitor module 50 further includes a DC bus bar 57. The power conversion device 20 may include the DC bus bar 57. The DC bus bar 57 may be provided separately from the components of the capacitor module 50. The DC bus bar 57 is a bus bar that electrically connects the DC power source 2 and the capacitor element 52. Like the bus bar 56, the DC bus bar 57 is also a metal plate made of a metal with good conductivity such as Cu. The DC bus bar 57 includes a DC bus bar 57P electrically connected to the P electrode 55P and a DC bus bar 57N electrically connected to the N electrode 55N. The DC bus bars 57P, 57N each have a connection portion 571, an extension portion 572, and a terminal portion 573.

[0062] The connection portion 571 is connected to a wiring member that electrically connects the semiconductor element 42 and the capacitor element 52. The wiring member extends in the arrangement direction of the main bodies 41, 51 in a plan view. In the illustrated power conversion device 20, the P terminal 44P, the N terminal 44N, the P bus bar 56P, and the N bus bar 56N form the wiring member. The connection portion 571 of the DC bus bar 57P is connected to the terminal portion 562 of the P bus bar 56P. The connection portion 571 of the DC bus bar 57N is connected to the terminal portion 562 of the N bus bar 56N.

[0063] The connection position of the connection portion 571 with respect to the terminal portion 562 is not particularly limited. It may be located closer to the main body portion 51 than the connection positions of the P terminal 44P and the N terminal 44N on the bus bar 56. The illustrated connection portion 571 is connected to the terminal portion 562 at a position overlapping the main body portion 51 in a plan view. The connection portion 571 is connected to the terminal portion 562 above the main body portion 51. The connection portion 571 extends in the Y direction so as to straddle (cross) the side wall 542 of the case 54 on the power module 40 side in a plan view. The connection portion 571 may be connected to the terminal portion 562 at a position between the main body portions 41, 51.

[0064] The extension portion 572 is continuous with the connection portion 571 and the terminal portion 573. The extension portion 572 electrically connects the connection portion 571 and the terminal portion 573. The extension portion 572 extends from the connection portion 571 in the Z direction toward the cooler 30. The extension portion 572 is continuous with the end of the connection portion 571 at a position overlapping with the recess 36 in a plan view. The extension portion 572 is provided at a position overlapping with the recess 36 in a plan view. The extension portion 572 is thermally connected to the cooler 30 at a position between the main body portions 41, 51. A thermally connected state refers to a state in which the extension portion 572 is connected via a member that has better thermal conductivity than air.

[0065] The illustrated power conversion device 20 includes a thermally conductive member 70. The thermally conductive member 70 includes an electrically insulating material. The thermally conductive member 70 is, for example, TIM or GF. The thermally conductive member 70 is disposed in the recess 36. The extension portion 572 extends from the connection portion 571 into the recess 36. A predetermined range from the tip of the extension portion 572 is disposed in the recess 36. Within the recess 36, the extension portion 572 is thermally connected to the cooler 30 (case 31) via the thermally conductive member 70 disposed in the recess 36.

[0066] At least a portion of the extension portion 572 is provided between the main body 41 of the power module 40 and the main body 51 of the capacitor module 50 in a plan view. The illustrated extension portion 572 extends in the X direction. A portion of the extension portion 572 is provided within the opposing region of the main bodies 41, 51 in a plan view, and another portion is provided outside the opposing region of the main bodies 41, 51. The entire length of the extension portion 572 is disposed within the recess 36 and is thermally connected to the cooler 30 via the heat conduction member 70.

[0067] In the illustrated DC bus bar 57, the extension portion 572 of the DC bus bar 57P and the extension portion 572 of the DC bus bar 57N are arranged in the same recess 36. The extension portion 572 of the DC bus bar 57P and the extension portion 572 of the DC bus bar 57N are aligned in the Y direction. The extension portion 572 of the DC bus bar 57P and the extension portion 572 of the DC bus bar 57N are arranged so that their plate surfaces face each other in the Y direction. The extension portion 572 of the DC bus bar 57P is arranged closer to the main body 51 than the extension portion 572 of the DC bus bar 57N. The extension portion 572 of the DC bus bar 57N is arranged closer to the main body 41 than the extension portion 572 of the DC bus bar 57P. The extension portion 572 of the DC bus bar 57N is arranged closer to the flow path 34 than the extension portion 572 of the DC bus bar 57P.

[0068] The terminal portion 573 is an external connection terminal for electrically connecting the DC bus bar 57 to the DC power source 2. The terminal portion 573 is electrically connected to the DC power source 2 via an input terminal block (not shown) or the like. The terminal portion 573 is continuous with the extension portion 572.

[0069] The illustrated terminal portion 573 is connected to the end of the extension portion 572 outside the opposing region of the main body portions 41, 51. The terminal portion 573 extends in the Y direction in a plan view. The terminal portion 573 extends from the extension portion 572 toward the power module 40. The terminal portion 573 is aligned with the main body portion 41 in the X direction. The terminal portion 573 of the DC bus bar 57P and the terminal portion 573 of the DC bus bar 57N are aligned with each other in the X direction. The terminal portion 573 of the DC bus bar 57P and the terminal portion 573 of the DC bus bar 57N are arranged such that their side surfaces face each other in the X direction. The terminal portion 573 of the DC bus bar 57N is arranged closer to the main body portion 41 than the terminal portion 573 of the DC bus bar 57P.

[0070] The current sensor 60 provides the above-described current sensor 13. The current sensor 60 is configured to detect phase currents individually. The current sensor 60 may be a magnetic detection type sensor equipped with a magnetoelectric conversion element, or a resistance detection type sensor equipped with a shunt resistor. The illustrated current sensor 60 is a magnetic detection type. The current sensor 60 includes a main body 61 and bus bars 62 provided corresponding to each phase.

[0071] The illustrated main body 61 includes a Hall element 63, which is a magnetoelectric conversion element, a resin member (not shown), a core, and a substrate. For convenience, the main body 61 is shown in a simplified form in FIGS. 2 to 4 . The main body 61 includes three Hall elements 63 and three cores corresponding to the bus bars 62. The Hall elements 63 are mounted on the substrate and disposed in the gaps of the corresponding cores. The cores and bus bars 62 are held in the resin member. The bus bars 62 pass through the annular regions of the corresponding cores. The substrate is fixed to the resin member. The bus bars 62 extend in the Y direction in a plan view.

[0072] In the illustrated power conversion device 20, the power module 40, the capacitor module 50, and the current sensor 60 are aligned in the Y direction. The power module 40 is disposed between the capacitor module 50 and the current sensor 60 in the Y direction.

[0073] Summary of First Embodiment The power conversion device 20 of this embodiment includes a cooler 30, power modules 40, capacitor modules 50, wiring members, a DC bus bar 57, and a heat conduction member 70. The wiring members extend in the alignment direction of the power main body and the capacitor main body, and electrically connect the semiconductor elements 42 and the capacitor elements 52. The DC bus bar 57 has a connection portion 571 connected to the wiring members and an extension portion 572. The extension portion 572 extends from the connection portion 571 toward the cooler 30 in a height direction perpendicular to the alignment direction, and is thermally connected to the cooler 30 via the heat conduction member 70 between the power main body and the capacitor main body.

[0074] In the illustrated power conversion device 20, the P terminal 44P, the N terminal 44N, and the bus bars 56 (P bus bars 56P and N bus bars 56N) correspond to wiring members. The main body 41 corresponds to the power main body, and the main body 51 corresponds to the capacitor main body. The Y direction corresponds to the arrangement direction, and the Z direction corresponds to the height direction.

[0075] Because the capacitor module 50 is disposed on one surface 30a of the cooler 30, the capacitor elements 52 can be effectively cooled. Because the DC bus bar 57 is thermally connected to the cooler 30 via the thermally conductive member 70 and cooled, the influence of heat generated in the DC bus bar 57 due to current flow on the capacitor elements 52 can be reduced. The DC bus bar 57 is thermally connected to the cooler 30 between the power body and the capacitor body in the arrangement direction. Because the DC bus bar 57 is thermally connected to the cooler 30 directly below the wiring member, an increase in the physical size can be suppressed. As described above, the influence of heat on the capacitor elements 52 can be reduced while suppressing an increase in the physical size.

[0076] As illustrated, the DC bus bar 57 may be disposed so that the thickness direction of the extension portion 572 is aligned with the arrangement direction. This makes it possible to more effectively suppress an increase in the size in the arrangement direction (Y direction).

[0077] As illustrated, the cooler 30 may be provided at a position overlapping the power body and may have a flow path 34 through which the coolant 35 flows. The wiring member may include a first capacitor bus bar connected to a first electrode of the capacitor element 52 and a second capacitor bus bar connected to a second electrode of the capacitor element 52 and disposed closer to a cooling surface 543 of the capacitor body with the cooler 30 than the first condenser bus bar. The DC bus bar 57 may include a first DC bus bar connected to the first condenser bus bar and a second DC bus bar connected to the second condenser bus bar. An extension portion 572 of the first DC bus bar may be disposed closer to the flow path 34 in the arrangement direction than the extension portion 572 of the second DC bus bar.

[0078] In the illustrated power conversion device 20, the N electrode 55N corresponds to the first electrode, and the P electrode 55P corresponds to the second electrode. The bus bars 56 correspond to the capacitor bus bars. The N bus bar 56N corresponds to the first capacitor bus bar, and the P bus bar 56P corresponds to the second capacitor bus bar. The DC bus bar 57N corresponds to the first DC bus bar, and the DC bus bar 57P corresponds to the second DC bus bar.

[0079] In the connection between the first condenser bus bar and the first DC bus bar, the first condenser bus bar is far from the cooling surface 543, but the extension portion 572 of the first DC bus bar is close to the flow path 34. In the connection between the second condenser bus bar and the second DC bus bar, the second DC bus bar is far from the flow path 34, but the second condenser bus bar is close to the cooling surface 543. Therefore, both the connection between the first condenser bus bar and the first DC bus bar and the connection between the second condenser bus bar and the second DC bus bar can be effectively cooled. Cooling of one of the connections is significantly inferior to that of the other, and this can suppress the capacitor elements 52 from being affected by heat.

[0080] As illustrated, the cooling surface 543 may include the bottom surface 51 a of the capacitor body. The capacitor element 52 can be cooled from the bottom surface 51 a side. In a configuration including the case 54, the structure of the power conversion device 20 can be simplified.

[0081] As illustrated, in the height direction, the first electrode may be provided on the upper surface 51b side of the capacitor element 52, and the second electrode may be provided on the bottom surface 51a side of the capacitor element 52. This allows the second capacitor bus bar, which is closer to the bottom surface 51a, to be cooled effectively.

[0082] As illustrated, the DC bus bar 57 may have a terminal portion 573 that is continuous with the extension portion 572 and electrically connected to the DC power source 2. At least the extension portion 572 and the terminal portion 573 of the DC bus bar 57 may be disposed in a position that does not overlap the power body and the capacitor body in a plan view. This can prevent an increase in the physical size in the height direction (Z direction).

[0083] <Modifications> The arrangement of the electrodes 55, bus bars 56, and DC bus bars 57 is not limited to the example described above. Alternatively, an N-electrode 55N may be provided on the bottom surface 51a, and a P-electrode 55P may be provided on the top surface 51b. The P-electrode 55P corresponds to the first electrode, and the N-electrode 55N corresponds to the second electrode. The P-bus bar 56P corresponds to the first capacitor bus bar, and the N-bus bar 56N closer to the cooling surface 543 (bottom surface 51a) corresponds to the second capacitor bus bar. The DC-bus bar 57P corresponds to the first DC bus bar, and the DC-bus bar 57N corresponds to the second DC bus bar. In this case, it is preferable to position the extension portion 572 of the DC-bus bar 57P closer to the flow path 34 in the arrangement direction than the extension portion 572 of the DC-bus bar 57N.

[0084] The arrangement of the heat conducting member 70 is not limited to the above example. For example, as shown in Fig. 5, the cooler 30 may be configured without the recess 36. In Fig. 5, the extension portion 572 is in contact with the heat conducting member 70 arranged on the flat surface 30a. The arrangements shown in Figs. 3 and 4 can prevent an increase in size in the Y direction while ensuring a contact area with the extension portion 572.

[0085] Second Embodiment This embodiment is a modification of the preceding embodiment, and the description of the preceding embodiment can be used. In the preceding embodiment, the bottom surface of the main body of the capacitor module serves as the cooling surface. In addition to this, or instead of this, the side surface of the main body may serve as the cooling surface.

[0086] Fig. 6 is a cross-sectional view showing an example of a power conversion device according to this embodiment. Fig. 6 corresponds to Fig. 3 . In the power conversion device 20 shown in Fig. 6 , a side wall 542 of a case 54 of a capacitor module 50 contacts a side surface of a recess 33 of a cooler 30. That is, a side surface 51c of the main body 51 facing the power module 40 is thermally connected to the cooler 30 and forms a cooling surface 543. As in the preceding embodiment, a bottom surface 51a of the main body 51 is also thermally connected to the cooler 30 and forms a cooling surface 543. The other configurations are the same as those described in the preceding embodiment.

[0087] Summary of Second Embodiment As illustrated, one surface 30a of cooler 30 has a stepped structure, and one surface also has a stepped structure, and cooling surface 543 of the capacitor body may include side surface 51c on the power module 40 side in the arrangement direction. This allows capacitor elements 52 to be cooled from the power module 40 side. Because the second condenser bus bar is close to side surface 51c, the second condenser bus bar can be cooled effectively.

[0088] <Modifications> The main body 51 may not have the case 54, and the cooler 30 may provide the storage space instead of the case 54. That is, the cooler 30 may also serve as the case 54. For example, by filling the recess 33 with a seal 53, the capacitor element 52 and a portion of the bus bar 56 can be sealed. In this case, the seal 53 forming the bottom surface 51a and the side surfaces 51c of the main body 51 contacts the bottom surface and the side surfaces of the recess 33. That is, the bottom surface 51a and the side surfaces 51c form the cooling surface. Since all four surfaces of the side surfaces 51c contact the cooler 30, cooling performance can be improved. Furthermore, by eliminating the case 54, the configuration can be simplified.

[0089] The capacitor module 50 may be fixed in a floating state relative to the bottom surface of the recess 33, with only the side surface 51c being thermally connected to the cooler 30. In this case, only the side surface 51c forms the cooling surface.

[0090] Third Embodiment This embodiment is a modification of the preceding embodiment, and the description of the preceding embodiment can be used. In the preceding embodiment, the first electrode is provided on the top surface of the main body of the capacitor module, and the second electrode is provided on the bottom surface. Alternatively, electrodes may be provided on the side surfaces of the main body.

[0091] Fig. 7 is a cross-sectional view showing an example of a power conversion device according to this embodiment. Fig. 7 corresponds to Fig. 3. In the power conversion device 20 shown in Fig. 7, the electrodes 55 are provided on the side surfaces of the capacitor element 52 in the Y direction. The P-electrode 55P is provided on the side surface on the power module 40 side. The N-electrode 55N is provided on the surface opposite the P-electrode 55P in the Y direction.

[0092] A bottom surface 51a of the main body 51 is thermally connected to the bottom surface of the recess 33. Of the side surfaces 51c, the side surface 51c on the power module 40 side is thermally connected to the side surface of the recess 33. The bottom surface 51a and the side surface 51c on the power module 40 side form a cooling surface 543.

[0093] The connecting portion 563 of the P bus bar 56P extends in the Z direction from the electrode connecting portion 561. The electrode connecting portion 561 and the connecting portion 563 of the P bus bar 56P are disposed near the side surface 51c that forms the cooling surface 543. The connecting portion 563 of the N bus bar 56N is generally crank-shaped, with both end portions extending in the Z direction and an intermediate portion extending in the Y direction. The electrode connecting portion 561 and the connecting portion 563 of the N bus bar 56N are disposed farther from the side surface 51c that forms the cooling surface 543 than the P bus bar 56P. The distance from the bottom surface 51a of the electrode connecting portion 561 of the P bus bar 56P and the electrode connecting portion 561 of the N bus bar 56N is approximately the same. The other configurations are the same as those described in the preceding embodiment.

[0094] As illustrated, in the arrangement direction, the second electrode may be provided on the surface of capacitor element 52 facing power module 40, and the first electrode may be provided on the surface opposite to the second electrode. For example, the second capacitor bus bar close to side surface 51 c facing power module 40 can be effectively cooled.

[0095] <Modifications> Although the example has been shown in which the bottom surface 51a and the side surface 51c are used as the cooling surface 543, this is not limiting. For example, only the bottom surface 51a may be used as the cooling surface 543. In this case, the electrode connection portion 561 of the P bus bar 56P may be disposed closer to the bottom surface 51a than the electrode connection portion 561 of the N bus bar 56N. As described in the second embodiment, only the side surface 51c may be used as the cooling surface 543.

[0096] As described in the second embodiment, the main body 51 may not have the case 54 , and the cooler 30 may provide the accommodation space instead of the case 54 .

[0097] (Fourth Embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used. In the preceding embodiment, a thermally conductive member such as a TIM or GF was disposed on one surface of the cooler. Instead of this, a resin molded body provided in the capacitor module may be used as the thermally conductive member.

[0098] Fig. 8 is a cross-sectional view showing an example of a power conversion device according to this embodiment. Fig. 8 corresponds to Fig. 3. Fig. 9 is a diagram showing a resin molded body. Fig. 9 also shows a DC bus bar integrally molded with the resin molded body as an insert part.

[0099] The power conversion device 20 includes a resin molded body 58 shown in FIGS. 8 and 9. The resin molded body 58 contains a filler for improving thermal conductivity. The capacitor module 50 does not include a case 54. Instead of the case 54, the cooler 30 functions as a case (metal case) that houses the sealing body 53. The sealing body 53 fills the recess 33 of the cooler 30. A portion of the resin molded body 58 is disposed within the case formed by the cooler 30. A portion of the resin molded body 58 is sealed by the sealing body 53. The resin molded body 58 includes a first frame 581, a second frame 582, and an annular frame 583.

[0100] The first frame 581 extends in the Y direction in a plan view. The second frame 582 extends in the X direction in a plan view. The second frame 582 extends from the side wall 323 toward the side wall 324. The illustrated resin molded body 58 includes five first frames 581 and two second frames 582. The five first frames 581 are lined up in the X direction at a predetermined interval. The two second frames 582 are lined up in the Y direction at a predetermined interval.

[0101] The first frame 581 and the second frame 582 each have a bottom wall-side frame portion 834 and a side wall-side frame portion 835. The bottom wall-side frame portion 834 is a portion arranged to face the bottom surface of the recess 33, i.e., the bottom wall of the case 31. The side wall-side frame portion 835 is a portion connected to the bottom wall-side frame portion 834 and arranged to face the side surface of the recess 33, i.e., the side wall of the case 31. In the illustrated resin molded body 58, the bottom wall-side frame portion 834 is arranged between each of the capacitor elements 52 and the bottom wall of the case 31. The side wall-side frame portion 835 is arranged between each of the capacitor elements 52 and the side wall of the case 31. The capacitor elements 52 connected to the bus bars 56 may contact the bottom wall-side frame portion 834. The capacitor elements 52 connected to the bus bars 56 may contact the side wall-side frame portion 835.

[0102] The first frame 581 has a bottom wall side frame portion 834 extending in the Y direction and a side wall side frame portion 835 that is connected to an end of the bottom wall side frame portion 834 and extends in the Z direction. The first frame 581 has the side wall side frame portions 835 at both ends. The second frame 582 has the bottom wall side frame portion 834 extending in the X direction and a side wall side frame portion 835 that is connected to an end of the bottom wall side frame portion 834 and extends in the Z direction. The second frame 582 has the side wall side frame portions 835 at both ends. The first frame 581 and the second frame 582 are connected to each other. The bottom wall side frame portion 834 of the first frame 581 and the bottom wall side frame portion 834 of the second frame 582 are connected to each other. The illustrated resin molded body 58 has ten connecting portions where the first frame 581 and the second frame 582 intersect and are connected.

[0103] The annular frame 583 has a generally rectangular ring shape in a plan view. All of the first frames 581 and second frames 582 are connected to the annular frame 583. The side wall frame portions 835 of the first frames 581 and second frames 582 are connected to the annular frame 583. The shape of the resin molded body 58 is maintained by the annular frame 583. The annular frame 583 forms the upper edge portion of the resin molded body 58. The annular frame 583 has a flange shape that extends outward from the main body portion 51.

[0104] Of the resin molded body 58, most of the first frame 581 and the second frame 582 are sealed by the sealing body 53. The first frame 581 and the second frame 582 are interposed between the opposing surfaces of all the capacitor elements 52 and the case 31 (cooler 30). In addition, holes 586 are located between the opposing surfaces of all the capacitor elements 52 and the case 31. The capacitor elements 52 and the bus bars 56 are thermally connected to the case 31 via the sealing body 53 arranged in the holes 586.

[0105] The DC bus bar 57 is held in the annular frame 583 as an insert part. The DC bus bar 57 is insert-molded together with the resin molded body 58. The extension portion 572 of the DC bus bar 57 is held in a portion of the annular frame 583 on the power module 40 side. A predetermined range of the extension portion 572 of the DC bus bar 57 from the tip is embedded in the resin molded body 58. The portion of the annular frame 583 that holds the extension portion 572 is disposed on one surface 30a of the cooler 30 (case 31). The portion of the annular frame 583 that holds the extension portion 572 is disposed between the main body portions 41 and 51. The extension portion 572 is thermally connected to the cooler 30 via the annular frame 583 of the resin molded body 58. The other configurations are similar to those described in the preceding embodiment.

[0106] Summary of Fourth Embodiment As illustrated, the resin molded body 58 may be used instead of the heat conduction member 70. This also makes it possible to achieve the same effects as the configuration including the heat conduction member 70.

[0107] A resin case 54 may be used instead of the resin molded body 58. The DC bus bar 57 may be held in the case 54 (resin case) as an insert part.

[0108] (Other Embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0109] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0110] When an element or layer is referred to as being "on," "coupled," "connected," or "coupled," it may be directly on, coupled, connected, or coupled to another element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly coupled" to another element or layer, no intervening elements or layers are present. Other terms used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items. That is, a reference to A and / or B means at least one of A and B.

[0111] Spatially relative terms such as "inside," "outside," "back," "below," "low," "top," "top," and the like are used herein to facilitate the description of one element or feature's relationship to other elements or features, as illustrated. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, elements described as "below" or "directly below" other elements or features would then be oriented "above" the other elements or features. Thus, the term "bottom" can encompass both an orientation of top and bottom. The device may also be oriented in other ways (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly.

[0112] Although the power module 40 is exemplified as a 2-in-1 package that provides the upper and lower arm circuits 9 for one phase, the power module 40 is not limited to this. The power module 40 may be, for example, a 6-in-1 package that provides the upper and lower arm circuits 9 for three phases, or a 1-in-1 package that provides one arm.

[0113] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0114] <Technical Idea 1> A power module (40) having a power body (41) including a semiconductor element (42) and disposed on the one surface, and a capacitor module (50) having a capacitor body (51) including a capacitor element (52) and disposed on the one surface, wiring members (44N, 44P, 56) extending in an arrangement direction of the power body and the capacitor body and electrically connecting the semiconductor element and the capacitor element, a DC bus bar (57) electrically connecting a DC power source and the capacitor element, and a heat conduction member (58, 70) including an electrical insulating material and interposed between the DC bus bar and the cooler, the DC bus bar has a connection portion (571) connected to the wiring member, and an extension portion (572) extending from the connection portion toward the cooler in a height direction perpendicular to the arrangement direction, and thermally connected to the cooler via the heat conduction member between the power main body and the capacitor main body.

[0115] <Technical Concept 2> The power conversion device according to Technical Concept 1, wherein the DC bus bar is arranged so that the plate thickness direction of the extension portion is aligned with the arrangement direction.

[0116] <Technical Idea 3> The power conversion device according to Technical Idea 1 or 2, wherein the cooler is provided at a position overlapping the power main body and has a flow path (34) through which a refrigerant flows, the capacitor elements have first electrodes (55N) and second electrodes (55P), the wiring members are capacitor bus bars connected to the electrodes of the capacitor elements, and include a first capacitor bus bar (56N) connected to the first electrode and a second capacitor bus bar (56P) connected to the second electrode and arranged closer to a cooling surface (543) of the capacitor main body with the cooler than the first capacitor bus bar, the DC bus bars include a first DC bus bar (57N) connected to the first capacitor bus bar and a second DC bus bar (57P) connected to the second capacitor bus bar, and the extension portion of the first DC bus bar is arranged closer to the flow path in the arrangement direction than the extension portion of the second DC bus bar.

[0117] <Technical Idea 4> The power conversion device according to Technical Idea 3, wherein the capacitor body has a bottom surface (51 a) facing the one surface in the height direction, a top surface (51 b) that is the surface opposite to the bottom surface in the height direction, and a side surface (51 c) that is a surface continuing to the bottom surface and the top surface.

[0118] <Technical Concept 5> The power conversion device according to Technical Concept 4, wherein the one surface has a stepped structure, and the cooling surface includes the side surface on the power module side in the arrangement direction.

[0119] <Technical Concept 6> The power conversion device according to Technical Concept 4 or 5, wherein the cooling surface includes the bottom surface.

[0120] <Technical Idea 7> The power conversion device according to any one of Technical Ideas 4 to 6, wherein, in the height direction, the first electrode is provided on the top surface side of the capacitor element, and the second electrode is provided on the bottom surface side of the capacitor element.

[0121] <Technical Idea 8> The power conversion device according to any one of Technical Ideas 4 to 6, wherein, in the arrangement direction, the second electrode is provided on a surface of the capacitor element facing the power module, and the first electrode is provided on a surface opposite to the second electrode.

[0122] <Technical Idea 9> The power conversion device according to any one of Technical Ideas 1 to 8, wherein the DC bus bar has a terminal portion (573) that is continuous with the extension portion and is electrically connected to the DC power supply, and at least the extension portion and the terminal portion of the DC bus bar are arranged at positions that do not overlap with the power main body and the capacitor main body in a plan view in the height direction.

Claims

1. A cooler (30) having one surface; a power module (40) having a power body (41) including a semiconductor element (42) and disposed on the one surface; a capacitor module (50) having a capacitor body (51) including a capacitor element (52) and disposed on the one surface; wiring members (44N, 44P, 56) extending in the juxtaposition direction of the power body and the capacitor body and electrically connecting the semiconductor element and the capacitor element; a DC bus bar (57) electrically connecting a DC power source and the capacitor element; and a heat conduction member (58, 70) including an electrically insulating material and interposed between the DC bus bar and the cooler. the DC bus bar has a connection portion (571) connected to the wiring member, and an extension portion (572) extending from the connection portion toward the cooler in a height direction perpendicular to the arrangement direction, and thermally connected to the cooler via the heat conduction member between the power main body and the capacitor main body.

2. The power conversion device according to claim 1, wherein the DC bus bar is arranged so that the thickness direction of the extension portion is aligned with the arrangement direction.

3. The power conversion device according to claim 2, wherein the cooler is provided at a position overlapping the power main body and has a flow path (34) through which a refrigerant flows, the capacitor element has a first electrode (55N) and a second electrode (55P), the wiring member is a capacitor bus bar connected to the electrodes of the capacitor element, and includes a first capacitor bus bar (56N) connected to the first electrode and a second capacitor bus bar (56P) connected to the second electrode and positioned closer to a cooling surface (543) of the capacitor main body with the cooler than the first capacitor bus bar, the DC bus bar includes a first DC bus bar (57N) connected to the first capacitor bus bar and a second DC bus bar (57P) connected to the second capacitor bus bar, and the extension portion of the first DC bus bar is positioned closer to the flow path in the arrangement direction than the extension portion of the second DC bus bar.

4. A power conversion device as described in claim 3, wherein the capacitor main body has a bottom surface (51a) facing the one surface in the height direction, a top surface (51b) that is the surface opposite the bottom surface in the height direction, and a side surface (51c) that is a surface connected to the bottom surface and the top surface.

5. The power conversion device according to claim 4, wherein the one surface has a stepped structure, and the cooling surface includes the side surface on the power module side in the arrangement direction.

6. The power conversion device according to claim 4, wherein the cooling surface includes the bottom surface.

7. A power conversion device according to any one of claims 4 to 6, wherein, in the height direction, the first electrode is provided on the top surface side of the capacitor element, and the second electrode is provided on the bottom surface side of the capacitor element.

8. A power conversion device according to any one of claims 4 to 6, wherein, in the arrangement direction, the second electrode is provided on a surface of the capacitor element facing the power module, and the first electrode is provided on a surface opposite to the second electrode.

9. A power conversion device as claimed in any one of claims 1 to 6, wherein the DC bus bar has a terminal portion (573) that is continuous with the extension portion and electrically connected to the DC power source, and at least the extension portion and the terminal portion of the DC bus bar are arranged in positions that do not overlap with the power main body portion and the capacitor main body portion when viewed in a plan view in the height direction.

Images