Power conversion device

Abstract

To provide a power conversion device in which inductance can be reduced.SOLUTION: A plurality of semiconductor modules (30) include an upper arm module (30H), and a lower arm module (30L) arranged with the upper arm module in a lamination direction. Heat exchange units (41) of a cooler (40) are disposed in multi-stages so as to cool the upper arm module and the lower arm module from both surface sides in the lamination direction, and the heat exchange units and the semiconductor modules constitute a lamination body (45). A capacitor module (50) is disposed on one end side of the lamination body in the lamination direction. A power source bus bar (61), electrically connecting the capacitor module and the semiconductor module, extends over at least one of the heat exchange units in the lamination direction.SELECTED DRAWING: Figure 15

Description

Cross - reference to related applications

[0001] This application is based on Japanese Patent Application No. 2021 - 165000 filed in Japan on October 6, 2021, and the contents of the basic application are hereby incorporated by reference in their entirety.

Technical Field

[0002] The disclosure in this specification relates to a power conversion device.

Background Art

[0003] Patent Document 1 discloses a power conversion device. This power conversion device includes a plurality of semiconductor modules, a cooler, a capacitor, and a plurality of bus bars. The cooler has a plurality of heat exchange parts arranged in multiple stages so as to sandwich each of the semiconductor modules from both sides. The plurality of bus bars include a power supply bus bar that electrically connects the capacitor and the semiconductor modules. The description of the prior art document is incorporated by reference as an explanation of the technical elements in this specification.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] In Patent Document 1, each of the semiconductor modules constitutes an upper and lower arm circuit for one phase. Such a semiconductor module has a semiconductor element that constitutes the upper arm and a semiconductor element that constitutes the lower arm inside, and these semiconductor elements are arranged side by side in one direction orthogonal to the stacking direction. For this reason, the PN current loop becomes large within the semiconductor module. Further, a capacitor is arranged in one direction orthogonal to the stacking direction with respect to the stacked body of the semiconductor module and the heat exchange part. A pipe for introducing or discharging a refrigerant with respect to the heat exchange part is arranged between the semiconductor module and the capacitor. For this reason, a power supply bus bar must be arranged across the pipe of the cooler, and the power supply bus bar becomes long. From the above viewpoints or other viewpoints not mentioned, further improvement of the power conversion device is required.

[0006] One disclosed object is to provide a power conversion device capable of reducing inductance.

[0007] The power conversion device disclosed herein A plurality of semiconductor modules including an upper arm module that constitutes the upper arm of the upper and lower arm circuit, and a lower arm module that constitutes the lower arm of the upper and lower arm circuit and is arranged side by side in the stacking direction with the upper arm module, A cooler having a plurality of heat exchange parts that are arranged in multiple stages so as to cool each of the upper arm module and the lower arm module from both sides in the stacking direction and form a stacked body together with the plurality of semiconductor modules, A capacitor arranged on one end side of the stacked body in the stacking direction, A plurality of bus bars including a power supply bus bar that electrically connects the capacitor and the semiconductor module and extends in the stacking direction so as to straddle at least one of the heat exchange parts, The power supply bus bar includes a positive electrode bus bar that electrically connects the positive electrode of the capacitor and the upper arm module, and a negative electrode bus bar that electrically connects the negative electrode of the capacitor and the lower arm module, A plurality of bus bars electrically connect the upper arm module and the lower arm module, and include output bus bars extending in a direction away from the capacitor in the stacking direction. Look, The cooler has an introduction pipe (42) connected to each of the heat exchange parts for introducing refrigerant into the heat exchange parts, and a discharge pipe (43) connected to each of the heat exchange parts for discharging the refrigerant that has flowed through the heat exchange parts. In one direction orthogonal to the stacking direction, the introduction pipe is connected to one end side of a plurality of heat exchange parts, and the discharge pipe is connected to the other end side of the plurality of heat exchange parts.

[0008] According to the disclosed power conversion device, a plurality of semiconductor modules are divided into an upper arm module and a lower arm module, and the upper arm module and the lower arm module are arranged side by side in the stacking direction. Thereby, the PN current loop can be reduced. Further, the capacitor is arranged in the stacking direction with respect to the stacked body, and the power supply bus bar is extended in the stacking direction so as to straddle at least one of the heat exchange portions. Thereby, the length of the power supply bus bar, that is, the current path can be shortened. As a result, a power conversion device capable of reducing inductance can be provided.

[0009] The plurality of disclosed aspects in this specification employ different technical means to achieve their respective purposes. The reference numerals in parentheses described in the claims and this section exemplify the correspondence with the parts of the embodiments described later, and are not intended to limit the technical scope. The objects, features, and effects disclosed in this specification will become clearer by referring to the subsequent detailed description and the accompanying drawings.

Brief Description of the Drawings

[0010]

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Embodiments for Carrying Out the Invention

[0011] Hereinafter, a plurality of embodiments will be described with reference to the drawings. In each embodiment, corresponding components may be denoted by the same reference numerals, and redundant descriptions may be omitted. When only a part of the configuration is described in each embodiment, the configuration of other embodiments described previously can be applied to other parts of the said configuration. Also, not only the combinations of configurations explicitly shown in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined with each other as long as there is no problem with the combination, even if not explicitly stated.

[0012] The power conversion device of this embodiment is applied to, for example, a moving body having a rotating electrical machine as a drive source. The moving body is, for example, an electric vehicle such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a flying body such as a drone, a ship, a construction machine, or an agricultural machine. Hereinafter, an example of application to a vehicle will be described.

[0013] (First Embodiment) First, based on FIG. 1, the schematic configuration of the drive system of a vehicle will be described.

[0014] (Drive System of Vehicle) As shown in FIG. 1, the drive system 1 of the vehicle includes a DC power source 2, a motor generator 3, and a power conversion device 4.

[0015] The DC power source 2 is a DC voltage source composed of a rechargeable secondary battery. The secondary battery is, for example, a lithium-ion battery or a nickel-metal hydride battery. The motor generator 3 is a three-phase AC rotating electrical machine. The motor generator 3 functions as a driving source for the vehicle, that is, an electric motor. The motor generator 3 functions as a generator during regeneration. The power conversion device 4 performs power conversion between the DC power source 2 and the motor generator 3.

[0016] (Circuit Configuration of Power Conversion Device) FIG. 1 shows the circuit configuration of the power conversion device 4. The power conversion device 4 includes a power conversion circuit. The power conversion device 4 of the present embodiment includes a smoothing capacitor 5, an inverter 6 which is a power conversion circuit, and a drive circuit 7.

[0017] 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 8 which is a power supply line on the high potential side and an N line 9 which is a power supply line on the low potential side. The P line 8 is connected to the positive electrode of the DC power supply 2, and the N line 9 is connected to the negative electrode of the DC power supply 2. The positive electrode of the smoothing capacitor 5 is connected to the P line 8 between the DC power supply 2 and the inverter 6. The negative electrode of the smoothing capacitor 5 is connected to the N line 9 between the DC power supply 2 and the inverter 6. The smoothing capacitor 5 is connected in parallel with the DC power supply 2.

[0018] The inverter 6 is a DC-AC conversion circuit. The inverter 6 converts the DC voltage into a three-phase AC voltage according to the switching control by a control circuit (not shown) and outputs it to the motor generator 3. Thereby, the motor generator 3 is driven to generate a predetermined torque. During the regenerative braking of the vehicle, the inverter 6 converts the three-phase AC voltage generated by the motor generator 3 receiving the rotational force from the wheels into a DC voltage according to the switching control by the control circuit and outputs it to the P line 8. Thus, the inverter 6 performs bidirectional power conversion between the DC power supply 2 and the motor generator 3.

[0019] The inverter 6 is configured to include upper and lower arm circuits 10 for three phases. The upper and lower arm circuits 10 are sometimes referred to as legs. The upper and lower arm circuits 10 each have an upper arm 10H and a lower arm 10L. Hereinafter, the upper arm 10H and the lower arm 10L may be simply denoted as arms 10H and 10L. The upper arm 10H and the lower arm 10L are serially connected between the P line 8 and the N line 9 with the upper arm 10H on the P line 8 side. The connection point between the upper arm 10H and the lower arm 10L is connected to the corresponding phase winding 3a in the motor generator 3 via the output line 11. The inverter 6 has six arms 10H and 10L. Each of the arms 10H and 10L is configured to include a switching element.

[0020] In the present embodiment, an n-channel insulated gate bipolar transistor 12 (hereinafter referred to as IGBT12) is adopted as the switching element that constitutes each of the arms 10H and 10L. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. A freewheeling diode 13 (hereinafter referred to as FWD13) is connected in anti-parallel to each of the IGBT12s.

[0021] In the upper arm 10H, the collector of the IGBT12 is connected to the P line 8. In the lower arm 10L, the emitter of the IGBT12 is connected to the N line 9. And the emitter of the IGBT12 in the upper arm 10H and the collector of the IGBT12 in the lower arm 10L are connected to each other. The anode of the FWD13 is connected to the emitter of the corresponding IGBT12, and the cathode is connected to the collector.

[0022] Note that the switching element is not limited to the IGBT12. For example, a MOSFET may be adopted. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor. In the case of a MOSFET, a parasitic diode (body diode) may be used as the freewheeling diode, or an external diode may be used.

[0023] The drive circuit 7 drives the switching elements that make up a power conversion circuit such as the inverter 6. Based on the drive command from the control circuit, the drive circuit 7 supplies a drive voltage to the gates of the IGBTs 12 of the corresponding arms 10H and 10L. By applying the drive voltage, the drive circuit drives the corresponding IGBT 12, that is, turns it on or off. The drive circuit may be referred to as a driver.

[0024] The power conversion device 4 may include a control circuit for the switching elements. The control circuit generates a drive command for operating the IGBT 12 and outputs it to the drive circuit 7. The control circuit generates the drive command based on, for example, a torque request input from a higher-level ECU (not shown) and signals detected by various sensors. ECU is an abbreviation for Electronic Control Unit. The control circuit may be provided within the higher-level ECU.

[0025] Examples of the various sensors include a current sensor, a rotation angle sensor, and a voltage sensor. The power conversion device 4 may include at least one of the sensors. The current sensor 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 is configured to include, for example, a processor and a memory. The control circuit outputs, for example, a PWM signal as the drive command. PWM is an abbreviation for Pulse Width Modulation.

[0026] The power conversion device 4 may include a converter as the power conversion circuit. The converter is a DC-DC conversion circuit that converts a DC voltage into a DC voltage of a different value. 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-described upper and lower arm circuits 10. According to this configuration, step-up and step-down are possible. The power conversion device 4 may include a filter capacitor for removing power supply noise from the DC power supply 2. The filter capacitor is provided between the DC power supply 2 and the converter.

[0027] <Structure of Power Conversion Device> FIG. 2 shows a power conversion device 4. FIG. 3 is a view inverted with respect to FIG. 2. FIG. 4 is an exploded perspective view. FIG. 5 shows the structure inside the case 20. FIG. 5 omits the case 20 with respect to FIG. 2. In FIGS. 2 to 5, the interior is shown through transparency.

[0028] As shown in FIGS. 2 to 5, the power conversion device 4 includes a case 20, a plurality of semiconductor modules 30, a cooler 40, a capacitor module 50, a bus bar 60, a circuit board 70, and the like.

[0029] Hereinafter, the stacking direction of the semiconductor module 30 and the heat exchange portion 41 of the cooler 40 is defined as the Z direction. The arrangement direction of the semiconductor modules 30 on the same arm side, which is orthogonal to the Z direction, is defined as the X direction. The direction orthogonal to both the Z direction and the X direction is defined as the Y direction. The X direction, the Y direction, and the Z direction are in a mutually orthogonal positional relationship.

[0030] <Case> The case 20 houses other elements constituting the power conversion device 4. The case 20 is, for example, a molded body made of aluminum die-cast. As shown in FIGS. 2 to 4, the case 20 of the present embodiment has a box shape with one side open. The case 20 has an opening on one side in the Y direction. The case 20 has a bottom wall 21 and side walls 22. The bottom wall 21 has a substantially rectangular planar shape. The side walls 22 are continuous with the bottom wall 21 and extend in the Y direction from the bottom wall 21. The side walls 22 are continuous with each of the four sides of the outer peripheral end of the bottom wall 21. The side walls 22 form a substantially rectangular ring shape in a plan view in the Y direction. The case 20 has four side walls 22.

[0031] The case 20 has through-holes 23 and 24 in one of its side walls 22. Pipes 42 and 43 of the cooler 40 are inserted into the through-holes 23 and 24. The through-holes 23 and 24 penetrate the inside and outside of the side wall 22 and open to the inner surface and the outer surface. The case 20 has openings (not shown) for electrically connecting the connectors 71 and 80 to the outside of the power conversion device 4. The case 20 has an opening for the connector 71 and an opening for the connector 80. The opening is, for example, a through-hole or a notch provided in the side wall 22.

[0032] The power conversion device 4 may include, together with the case 20, a cover (lid) that closes the opening on one side of the case 20. The case 20 and the cover may be referred to as a housing. In a configuration without a cover, elements accommodated in the case 20 may be sealed liquid-tightly by disposing a filling material such as potting resin in the case 20. In a configuration with a cover, the inside of the housing may be sealed liquid-tightly by disposing a sealing material at the opposing portions between the case 20 and the cover, at the opposing portions between the wall surfaces of the through-holes 23 and 24 and the pipes 42 and 43, and at the opposing portions between the housings of the connectors 71 and 80 and the wall surfaces of the openings.

[0033] <Semiconductor module> FIG. 6 shows the semiconductor module 30. In FIG. 6, as an example, the upper arm module 30H is shown. FIG. 7 shows the arrangement of the semiconductor element 32, the substrates 33 and 34, the surface metal bodies 332 and 342 of the substrates 33 and 34, and the main terminals 35 in the semiconductor module 30. In FIG. 7, for clarity of the arrangement, the substrate 34 is shown inverted 180 degrees with respect to the substrate 33, and the surface metal bodies 332 and 342 of the substrates 33 and 34 are shown in the same plane.

[0034] A plurality of semiconductor modules 30 constitute the above-described upper and lower arm circuits 10, that is, the inverter 6 (power conversion circuit). The plurality of semiconductor modules 30 include an upper arm module 30H that constitutes the upper arm 10H and a lower arm module 30L that constitutes the lower arm 10L.

[0035] In this embodiment, one semiconductor module 30 constitutes one arm 10H or 10L. As shown in FIG. 4 and the like, a plurality of semiconductor modules 30 include three upper arm modules 30H that constitute the three-phase upper arm 10H and three lower arm modules 30L that constitute the three-phase lower arm 10L. Also, all the semiconductor modules 30 have a common structure with each other. As shown in FIGS. 6 and 7, each semiconductor module 30 includes a sealing body 31, a semiconductor element 32, substrates 33 and 34, a main terminal 35, and a signal terminal 36.

[0036] The sealing body 31 seals a part of other elements constituting the semiconductor module 30. The remaining part of the other elements is exposed outside the sealing body 31. The sealing body 31 is made of, for example, resin. The sealing body 31 is formed by a transfer molding method using, for example, an epoxy resin as a material. The sealing body 31 may be formed using, for example, a gel. The gel is filled (arranged) in, for example, the opposing region between the pair of substrates 33 and 34.

[0037] The semiconductor element 32 is formed by forming a switching element on a semiconductor substrate made of, for example, silicon (Si), a wide bandgap semiconductor having a wider bandgap than silicon, or the like. The switching element has a vertical structure so that a main current flows in the thickness direction of the semiconductor substrate. Examples of the wide bandgap semiconductor include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), and diamond. The semiconductor element 32 may be referred to as a power element, a semiconductor chip, or the like.

[0038] The semiconductor element 32 of this embodiment is formed by forming the above-described n-channel IGBT 12 and FWD 13, that is, an RC (Reverse Conducting)-IGBT, on a semiconductor substrate made of Si. The IGBT 12 has a vertical structure such that the main current flows in the thickness direction of the semiconductor element 32 (semiconductor substrate). The semiconductor element 32 has main electrodes of a switching element on both surfaces in its thickness direction. Specifically, as the main electrodes, it has an emitter electrode 32E on the front surface and a collector electrode 32C on the back surface. The emitter electrode 32E is formed on a part of the front surface. The collector electrode 32C is formed over substantially the entire back surface. In FIG. 7, the collector electrode 32C and the emitter electrode 32E are shown by broken lines.

[0039] The main current flows between the collector electrode 32C and the emitter electrode 32E. The semiconductor element 32 has pads (not shown) which are signal electrodes, on the formation surface of the emitter electrode 32E. The semiconductor element 32 is arranged such that its thickness direction is substantially parallel to the Z direction. The semiconductor module 30 of this embodiment includes one semiconductor element 32.

[0040] The substrates 33 and 34 are arranged so as to sandwich the semiconductor element 32 in the thickness direction of the semiconductor element 32, that is, the Z direction. The substrates 33 and 34 are arranged such that at least a part of them faces each other in the Z direction. The substrates 33 and 34 enclose all of the semiconductor elements 32 that constitute one arm 10H, 10L in a plan view in the Z direction.

[0041] The substrates 33 and 34 are electrically connected to the semiconductor element 32. The substrate 33 is arranged on the collector electrode 32C side with respect to the semiconductor element 32. The substrate 34 is arranged on the emitter electrode 32E side with respect to the semiconductor element 32. The substrate 33 is electrically connected to the collector electrode 32C and provides a wiring function. Similarly, the substrate 34 is electrically connected to the emitter electrode 32E and provides a wiring function. The substrates 33 and 34 provide a heat dissipation function for dissipating the heat generated by the semiconductor element 32.

[0042] The substrate 33 has an insulating base material 331, a front surface metal body 332, and a back surface metal body 333. The front surface metal body 332 is disposed on the front surface of the insulating base material 331 which is the surface on the semiconductor element 32 side. The back surface metal body 333 is disposed on the back surface of the insulating base material 331. The substrate 34 has an insulating base material 341, a front surface metal body 342, and a back surface metal body 343. The front surface metal body 342 is disposed on the front surface of the insulating base material 341 which is the surface on the semiconductor element 32 side. The back surface metal body 343 is disposed on the back surface of the insulating base material 341. The substrates 33 and 34 are laminated substrates of an insulating base material and a metal body. Hereinafter, the front surface metal bodies 332 and 342 and the back surface metal bodies 333 and 343 may be simply referred to as metal bodies 332, 333, 342, and 343.

[0043] The insulating base material 331 electrically separates the metal bodies 332 and 333. Similarly, the insulating base material 341 electrically separates the metal bodies 342 and 343. The main materials of the insulating base materials 331 and 341 are resin or ceramic which is an inorganic material. The material compositions of the insulating base materials 331 and 341 may be common (identical) to each other or different from each other.

[0044] The metal bodies 332, 333, 342, and 343 are provided, for example, as metal plates or metal foils. The metal bodies 332, 333, 342, and 343 are formed of a metal having good conductivity and heat conductivity such as Cu or Al as a material. The front surface metal bodies 332 and 342 provide wirings, that is, circuits.

[0045] The front surface metal bodies 332 and 342 of the present embodiment are patterned. As shown in FIG. 7, the front surface metal body 332 has a wiring portion 334 that provides a wiring function and a dummy wiring portion 335 that does not provide a wiring function. The wiring portion 334 electrically connects the collector electrode 32C of the semiconductor element 32 and the main terminal 35 (collector terminal 35C) corresponding thereto. The wiring portion 334 has a substantially L shape in a plane, and has a substantially rectangular base portion 334a in a plane and a convex portion 334b extending in the Y direction from one side of the base portion. The collector electrode 32C is connected to the base portion 334a of the wiring portion 334, and the collector terminal 35C is connected to the convex portion 334b.

[0046] The dummy wiring portion 335 is electrically separated from the wiring portion 334. The dummy wiring portion 335 is provided so as to be aligned with the convex portion 334b of the wiring portion 334 in the X direction. An emitter terminal 35E, which is a main terminal 35, is connected to the dummy wiring portion 335. The dummy wiring portion 335 supports the emitter terminal 35E.

[0047] Similar to the surface metal body 332, the surface metal body 342 has a wiring portion 344 that provides a wiring function and a dummy wiring portion 345 that does not provide a wiring function. The wiring portion 344 electrically connects the emitter electrode 32E of the semiconductor element 32 and the corresponding main terminal 35 (emitter terminal 35E). The wiring portion 344 has a substantially L-shaped plane, and has a base portion 344a having a substantially rectangular plane and a convex portion 344b extending in the Y direction from one side of the base portion. The emitter electrode 32E is connected to the base portion 334a of the wiring portion 344, and the emitter terminal 35E is connected to the convex portion 344b.

[0048] The dummy wiring portion 345 is electrically separated from the wiring portion 344. The dummy wiring portion 345 is provided so as to be aligned with the convex portion 344b of the wiring portion 344 in the X direction. A collector terminal 35C, which is a main terminal 35, is connected to the dummy wiring portion 345. The dummy wiring portion 335 supports the collector terminal 35C.

[0049] The surface metal body 332 and the surface metal body 342 are arranged in a left-right reversed configuration in a plan view from the Z direction. In the X direction, the arrangement of the convex portion 334b and the dummy wiring portion 335 is opposite to the arrangement of the convex portion 344b and the dummy wiring portion 345.

[0050] The back metal bodies 333 and 343 are electrically separated from the circuit including the semiconductor element 32 and the surface metal bodies 332 and 342 by the insulating substrates 331 and 341. The heat generated by the semiconductor element 32 is transmitted to the back metal bodies 333 and 343 through the surface metal bodies 332 and 342 and the insulating substrates 331 and 341. The back metal bodies 333 and 343 provide a heat dissipation function. The back metal bodies 333 and 343 may be patterned to substantially coincide with the corresponding surface metal bodies 332 and 342 in plan view, or may have a pattern different from that of the surface metal bodies 332 and 342. They may also be in a so-called solid pattern substantially coinciding with the insulating substrates 331 and 341. In the present embodiment, the pattern of the back metal body 333 substantially coincides with that of the surface metal body 332, and the pattern of the back metal body 343 substantially coincides with that of the surface metal body 342.

[0051] To further enhance the heat dissipation effect, at least one of the back metal bodies 333 and 343 may be exposed from the encapsulant 31. In the present embodiment, the back metal body 333 is exposed from one surface of the encapsulant 31, and the back metal body 343 is exposed from the back surface of the encapsulant 31.

[0052] Note that the wiring member for electrically connecting the main electrode of the semiconductor element 32 and the main terminal 35 is not limited to the above-described substrates 33 and 34. For example, a heat sink which is a metal plate may be employed. The heat sink also provides the above-described heat dissipation function. The heat sink is provided, for example, as a part of a lead frame together with the main terminal 35, the signal terminal 36, and the like. When the heat sink is exposed from the encapsulant 31, an insulating member such as a ceramic plate can be disposed between the heat sink and the heat exchange portion 41 of the cooler 40 to electrically separate the heat sink from the heat exchange portion 41.

[0053] The main terminal 35 is an external connection terminal electrically connected to the main electrode of the semiconductor element 32. The main terminal 35 includes a collector terminal 35C electrically connected to the collector electrode 32C and an emitter terminal 35E electrically connected to the emitter electrode 32E. The collector terminal 35C is connected to the collector electrode 32C via the wiring portion 334 of the surface metal body 332. The emitter terminal 35E is connected to the emitter electrode 32E via the wiring portion 344 of the surface metal body 342. The emitter terminal 35E corresponds to the first main terminal connected to the surface (emitter electrode 32E) of the semiconductor element 32. The collector terminal 35C corresponds to the second main terminal connected to the back surface (collector electrode 32C) of the semiconductor element 32.

[0054] Each main terminal 35 extends in the Y direction and has a portion disposed inside and outside the sealing body 31. Each main terminal 35 protrudes externally from one of the side surfaces of the sealing body 31 in the Y direction. The protruding portions of the collector terminal 35C and the emitter terminal 35E are arranged side by side in the X direction. The protruding portion of the main terminal 35 may have only a portion extending in the Y direction or may be bent midway.

[0055] As shown in FIG. 6, the protruding portion of the present embodiment has a bent portion 351, a root portion 352, and a tip portion 353, respectively. The root portion 352 is the portion from the sealing body 31 to the bent portion 351 in the protruding portion. The thickness direction of the root portion 352 is substantially parallel to the Z direction, and the root portion 352 extends in the Y direction. The tip portion 353 is the portion from the bent portion 351 to the protruding tip. The thickness direction of the tip portion 353 is substantially parallel to the Y direction, and the tip portion 353 extends in the Z direction. The protruding portion of the main terminal 35 bends at the bent portion 351 at an angle of approximately 90 degrees and forms a substantially L shape in the YZ plane.

[0056] The extending length L1 of the root portion 352 may be shorter or longer than the extending length L2 of the tip portion 353. The extending lengths L1 and L2 may be equal to each other. In the present embodiment, the extending length L1 of the root portion 352 is shorter than the extending length L2 of the tip portion 353. That is, the protruding portion of the main terminal 35 bends in the vicinity of the sealing body 31.

[0057] The tip portion 353 may extend in a direction approaching the capacitor module 50 in the Z direction or in a direction moving away therefrom. In the common semiconductor module 30, the tip portions 353 of the collector terminal 35C and the emitter terminal 35E may extend in the same direction or may extend in opposite directions to each other. In the present embodiment, the tip portions 353 of the collector terminal 35C and the emitter terminal 35E extend in the same direction.

[0058] The signal terminal 36 is an external connection terminal electrically connected to the pad of the semiconductor element 32. The signal terminal 36 extends in the Y direction and protrudes to the outside from the surface of the sealing body 31 opposite to the side where the main terminal 35 protrudes.

[0059] The connection form between the signal terminal 36 and the pad is not particularly limited. Connection may be made using bonding wires. When using bonding wires, a conductive spacer may be interposed between the substrate 34 and the emitter electrode 32E of the semiconductor element 32 to ensure the height of the bonding wires. Instead of bonding wires, other wiring members may be used. Connection may also be made via a bonding material such as solder.

[0060] <Cooler> FIG. 8 shows the arrangement of the semiconductor module 30 and the cooler 40. In FIG. 8, for the sake of convenience, the structure of the main terminal 35 is illustrated in a simplified manner. FIG. 9 is a plan view showing the arrangement of the semiconductor module 30, the cooler 40, and the capacitor module 50. In FIG. 9, for the sake of convenience, the case 20 is shown in cross section and elements such as the bus bar 60 are omitted from the illustration.

[0061] The cooler 40 is formed using a metal material having excellent thermal conductivity, for example, an aluminum-based material. As shown in FIGS. 4, 8, 9, etc., the cooler 40 includes a heat exchange portion 41, an introduction pipe 42, and a discharge pipe 43.

[0062] The heat exchange part 41 has an overall flat tubular shape. The heat exchange part 41 is configured to have a flow path inside, for example, using a pair of plates (thin metal plates). At least one of the pair of plates is processed into a shape that bulges in the Z direction by pressing. Then, the outer peripheral edges of the pair of plates are fixed to each other by caulking or the like, and are joined to each other over the entire circumference by brazing or the like. As a result, a flow path through which the refrigerant can flow is formed between the pair of plates, and it can be used as the heat exchange part 41.

[0063] The heat exchange parts 41 are arranged in multiple stages in the Z direction so as to cool each of the semiconductor modules 30 from both sides. The heat exchange parts 41 sandwich the semiconductor modules 30 in the Z direction. The heat exchange parts 41 and the semiconductor modules 30 together constitute a laminate 45.

[0064] Each of the pipes 42 and 43 is arranged across the inside and outside of the case 20. Each of the pipes 42 and 43 may be constituted by one member, or may be configured by connecting a plurality of members. The pipes 42 and 43 are connected to each of the heat exchange parts 41. By supplying the refrigerant to the pipe 42 by a pump (not shown), the refrigerant flows through the flow paths of each of the heat exchange parts 41 arranged in multiple stages. As a result, each of the semiconductor modules 30 is cooled. The refrigerant that has flowed through each of the heat exchange parts 41 is discharged through the pipe 43. As the refrigerant, a phase-changing refrigerant such as water or ammonia, or a non-phase-changing refrigerant such as an ethylene glycol-based refrigerant can be used.

[0065] <Arrangement of a plurality of semiconductor modules> As shown in FIG. 8 and the like, in the laminate 45, the semiconductor modules 30 and the heat exchange parts 41 are alternately arranged. Heat exchange parts 41 are arranged at both ends of the laminate 45. In the laminate 45, the heat exchange parts 41 are arranged in three stages in the Z direction. Here, the heat exchange part 41 closest to the capacitor module 50 is the first stage, the middle heat exchange part 41 is the second stage, and the heat exchange part 41 farther from the capacitor module 50 is the third stage.

[0066] In the laminate 45, an upper arm module 30H is disposed between the first-stage heat exchange section 41 and the second-stage heat exchange section 41. The three upper arm modules 30H that constitute the three-phase upper arm 10H are arranged side by side in the X direction with the same orientation. The three upper arm modules 30H are arranged in the order of U phase, V phase, and W phase. The collector terminal 35C of each upper arm module 30H functions as a P terminal that is electrically connected to the positive electrode of the capacitor element 52. The P terminal may be referred to as a positive electrode terminal, a high-potential power supply terminal, or the like. The emitter terminal 35E of each upper arm module 30H functions as an O terminal that is electrically connected to the corresponding-phase winding 3a of the motor generator 3. The O terminal may be referred to as an output terminal, an AC terminal, or the like.

[0067] In the laminate 45, a lower arm module 30L is disposed between the second-stage heat exchange section 41 and the third-stage heat exchange section 41. The three lower arm modules 30L that constitute the three-phase lower arm 10L are arranged side by side in the X direction with the same orientation. The three lower arm modules 30L are arranged in the same order as the upper arm module 30H. The collector terminal 35C of each lower arm module 30L functions as an O terminal. The emitter terminal 35E of each lower arm module 30L functions as an N terminal that is electrically connected to the negative electrode of the capacitor element 52. The N terminal may be referred to as a negative electrode terminal, a low-potential power supply terminal, or the like.

[0068] As described above, the upper arm module 30H is arranged closer to the capacitor module 50, and the lower arm module 30L is arranged farther from the capacitor module 50. The lower arm module 30L corresponds to the first semiconductor module, and the upper arm module 30H corresponds to the second semiconductor module. Each semiconductor module 30 has a common structure with each other. In the Z direction, the upper arm module 30H and the lower arm module 30L of the same phase are arranged to face each other via the heat exchange part 41. The collector terminal 35C of the upper arm module 30H of the same phase and the emitter terminal 35E of the lower arm module 30L are arranged to face each other.

[0069] The laminate 45 is pressed in the Z direction by the pressing member 46. By the pressing member 46, the semiconductor module 30 and the heat exchange part 41 are held with good thermal conductivity. As described above, since the substrates 33 and 34 are adopted in this embodiment, it is not necessary to arrange an insulating member for electrically separating the semiconductor module 30 and the heat exchange part 41. The semiconductor module 30 and the heat exchange part 41 may be in direct contact with each other, or a heat conductive member such as a heat conductive gel may be interposed between the semiconductor module 30 and the heat exchange part 41.

[0070] As an example, the pressing member 46 of this embodiment has a pressing plate 461, an elastic member 462, and a bolt 463. The pressing plate 461 is arranged so that the laminate 45 is positioned between it and the capacitor module 50 in the Z direction. The elastic member 462 is, for example, one that generates a pressing force by elastic deformation such as rubber or a metal spring. The elastic member 462 is arranged between the pressing plate 461 and the third-stage heat exchange part 41. The pressing plate 461 is fixed to the case 51 of the capacitor module 50 by the bolt 463 while holding the elastic member 462 between it and the laminate 45.

[0071] As shown in FIG. 4, the pressure plate 461 is substantially rectangular in a plan view in the Z direction, and has through holes 464 for bolts 463 at its four corners. The pressure plate 461 is fixed to the case 51 by bolts 463 arranged at the four corners. By fixing the pressure plate 461, the elastic member 462 is elastically deformed, and the laminate 45 is pressed against the case 51 by the reaction force. The laminate 45 is held in a pressed state between the pressure plate 461 and the case 51.

[0072] <Capacitor module> As shown in FIGS. 4, 5, and 9, the capacitor module 50 includes a case 51 and capacitor elements 52. The capacitor module 50 (capacitor elements 52) corresponds to a capacitor. The case 51 is formed using a resin material or a metal material, and has a box shape with one side open. The case 51 has one side open in the Y direction. The case 51 is open on the side opposite to the opening of the case 20. The case 51 has a substantially rectangular shape in a plane with the X direction as the longitudinal direction and the Z direction as the short direction.

[0073] The capacitor elements 52 are housed (arranged) in the case 51. The capacitor elements 52 constitute the smoothing capacitor 5 described above. As the capacitor elements 52, for example, film capacitor elements can be employed. The number of capacitor elements 52 is not particularly limited. It may be only one or a plurality. As an example, the capacitor module 50 of the present embodiment includes six capacitor elements 52. The six capacitor elements 52 are arranged in two rows in the Z direction and three columns in the X direction. The six capacitor elements 52 are substantially rectangular parallelepiped-shaped as a whole. Each capacitor element 52 has metal electrodes (not shown) at both ends in the Y direction. In each capacitor element 52, the metal electrode on the positive electrode side is provided on the bottom surface which is the end portion on the bottom wall side of the case 51, and the metal electrode on the negative electrode side is provided on the upper surface which is the end portion on the opening side of the case 51.

[0074] The capacitor module 50 may include a sealing body (not shown). The sealing body is filled in the case 51 to seal the capacitor element 52. The capacitor module 50 may include terminals (not shown). The terminals are, for example, plate-shaped metal members connected to the metal electrodes of the capacitor element 52.

[0075] As shown in FIGS. 5 and 9, etc., the capacitor module 50 is disposed on one end side of the laminate 45 in the Z direction. In a plan view in the Z direction, the capacitor module 50 is disposed so as to overlap the laminate 45.

[0076] <Bus bar> FIG. 10 is a cross-sectional view corresponding to the X-X line of FIG. 9. In FIG. 10, for the sake of convenience, only the laminate 45, the capacitor element 52, the bus bar 60, and the circuit board 70 are shown. FIG. 11 is a plan view showing the arrangement of each bus bar 60. FIG. 11 corresponds to FIG. 8. FIG. 12 shows the state before the extension portion 67 of the negative bus bar 61N is arranged, and FIG. 13 shows the state after the extension portion 67 is arranged. In FIGS. 12 and 13, for the sake of convenience, the extension portion 65 of the positive bus bar 61P and the extension portion 68 of the negative bus bar 61N are omitted.

[0077] The bus bar 60 is a wiring member electrically connected to the semiconductor module 30. The bus bar 60 is a plate-shaped metal member. The bus bar 60 is connected to the corresponding main terminal 35 by soldering, resistance welding, laser welding, etc. As shown in FIGS. 4, 10, 11, etc., the bus bar 60 includes a power bus bar 61 and an output bus bar 62.

[0078] The power bus bar 61 electrically connects the semiconductor module 30 and the capacitor element 52. The power bus bar 61 includes a positive electrode bus bar 61P and a negative electrode bus bar 61N. The positive electrode bus bar 61P electrically connects each of the collector terminals 35C (P terminals) of the upper arm module 30H and the positive electrode of the capacitor element 52. The positive electrode bus bar 61P may be referred to as a P bus bar, a high-potential power bus bar, etc. The positive electrode bus bar 61P constitutes at least a part of the above-described P line 8. The positive electrode bus bar 61P corresponds to the second power bus bar.

[0079] The positive electrode bus bar 61P has a base portion 63 and extending portions 64, 65. The base portion 63 is connected to the positive electrode of the capacitor element 52. The base portion 63 is disposed within the case 51 and includes portions facing the bottom wall of the case 51 and two side walls in the Z direction. The base portion 63 faces three surfaces of the substantially rectangular parallelepiped-shaped capacitor element 52. The base portion 63 has a bottom surface facing portion 631, side surface facing portions 632, 633, and a bent portion 634.

[0080] The bottom surface facing portion 631 faces the bottom surface of the capacitor element 52. The side surface facing portion 632 faces the side surface of the capacitor element 52 on the laminate 45 side. The side surface facing portion 633 faces the side surface of the capacitor element 52 on the side opposite to the side surface facing portion 632 in the Z direction. The bent portion 634 is bent at an angle of approximately 90 degrees with respect to the side surface facing portion 632. The bent portion 634 is continuous with the side surface facing portion 632 and extends from the side surface facing portion 632 in the Z direction and toward the laminate 45 side. The bent portion 634 is disposed outside the case 51.

[0081] The extended part 64 is continuous with the bent part 634 of the base part 63 and extends in the Z direction. The width of the extended part 64 is narrower than the width of the base part 63. The positive electrode bus bar 61P has three extended parts 64 corresponding to each phase. The three extended parts 64 extend in the same direction from the common bent part 634. The three extended parts 64 are arranged in the X direction. The plate thickness direction of the extended part 64 is substantially parallel to the Y direction. The plate surface of the extended part 64 faces the plate surface of the tip part 353 of the collector terminal 35C of the upper arm module 30H. And at the location where the plate surfaces face each other, the extended part 64 and the collector terminal 35C of the upper arm module 30H are connected. Each of the extended parts 64 straddles (crosses) the first-stage heat exchange part 41 in the Z direction.

[0082] The extended part 65 is on the side opposite to the extended part 64 and is continuous with the base part 63. The extended part 65 extends in the direction opposite to the extended part 64 from the base part 63. The width of the extended part 65 is narrower than the width of the base part 63. The extended part 65 constitutes a connector 80 for connecting to the DC power supply 2. The extended part 65 is the positive electrode terminal of the connector 80. The positive electrode bus bar 61P with the above-described configuration may be formed, for example, by processing a single metal plate or by connecting (joining) a plurality of members.

[0083] The negative electrode bus bar 61N electrically connects each of the emitter terminals 35E (N terminals) of the lower arm module 30L and the negative electrode of the capacitor element 52. The negative electrode bus bar 61N may be referred to as an N bus bar, a low-potential power supply bus bar, etc. The negative electrode bus bar 61N constitutes at least a part of the N line 9. The negative electrode bus bar 61N corresponds to the first power supply bus bar.

[0084] The negative electrode bus bar 61N has a base portion 66 and extending portions 67 and 68. The base portion 66 is connected to the negative electrode of the capacitor element 52. At least a part of the base portion 66 is disposed outside the case 51. The base portion 66 has a covering portion 661 and an opposing portion 662. The covering portion 661 is disposed so as to cover the entire capacitor element 52 having a substantially rectangular parallelepiped shape in a plan view in the Y direction. The covering portion 661 faces the upper surface of the capacitor element 52 and is connected to the negative electrode. The opposing portion 662 is continuous with the covering portion 661 and extends toward the laminate 45 side in the Z direction. The opposing portion 662 is disposed so as to substantially coincide with the bent portion 634 of the positive electrode bus bar 61P in a plan view in the Z direction. The thickness direction of the opposing portion 662 is substantially parallel to the Y direction. In the X direction, the width of the opposing portion 662 is narrower than the width of the covering portion 661. The opposing portion 662 and the bent portion 634 of the positive electrode bus bar 61P face each other with the plate surfaces spaced apart.

[0085] The extending portion 67 is connected (joined) to the opposing portion 662 of the base portion 66. The extending portion 67 is provided separately from the base portion 66 and is integrated by the connection. The extending portion 67 includes a portion that is continuous with the base portion 66 and extends toward the laminate 45 side in the Z direction. The thickness direction of the extending portion 67 is substantially parallel to the Y direction. The plate surface of the extending portion 67 faces the plate surface of the tip portion 353 of the emitter terminal 35E of the lower arm module 30L. And at the location where the plate surfaces face each other, the extending portion 67 and the emitter terminal 35E of the lower arm module 30L are connected. The extending portion 67 is disposed so as to cover at least a part of the protruding portion of the main terminal 35, at least a part of the extending portion 64 of the positive electrode bus bar 61P, and at least a part of the output bus bar 62. The extending portion 67 straddles (crosses) the first-stage heat exchange portion 41 and the second-stage heat exchange portion 41 in the Z direction.

[0086] As shown in FIGS. 11 and 13, etc., the extension part 67 has a slit 671, a parallel running part 672, an opposing part 673, and a connecting part 674. The slit 671 is provided between the upper arm module 30H and the lower arm module 30L in a plan view in the Y direction. The slit 671 is provided between the collector terminal 35C of the upper arm module 30H and the emitter terminal 35E of the lower arm module 30L. The slit 671 may be referred to as a notch. The extension part 67 has three-phase slits 671. The three slits 671 are arranged side by side in the X direction.

[0087] The parallel running part 672 has a portion adjacent to the slit 671 in the X direction. The parallel running part 672 defines the slit 671. At least a part of the parallel running part 672 runs parallel to the output bus bar 62. The parallel running part 672 and the output bus bar 62 face each other with their plate surfaces separated. The parallel running part 672 extends in the Z direction and maintains the facing relationship with the output bus bar 62 in its extending direction. The extension part 67 has three-phase parallel running parts 672. The three parallel running parts 672 are arranged side by side in the X direction.

[0088] The opposing part 673 has a portion adjacent to the slit on the capacitor module 50 side in the Z direction. The opposing part 673 defines the slit 671. The opposing part 673 extends from the parallel running part 672 in the X direction. Each of the opposing part 673 and the extension part 64 of the positive electrode bus bar 61P faces each other with their plate surfaces separated. The opposing part 673 maintains the facing relationship with the extension part 64, for example, over the entire length of the extension part 64.

[0089] The connecting part 674 is adjacent to the slit 671 on the side opposite to the opposing part 673 in the Z direction. The connecting part 674 defines the slit 671. The connecting part 674 extends from the parallel running part 672 in the X direction. The plate surface of the connecting part 674 faces the plate surface of the tip part 353 of the emitter terminal 35E of the lower arm module 30L. And at the location where the plate surfaces face each other, the connecting part 674 and the emitter terminal 35E of the lower arm module 30L are connected.

[0090] As shown in FIG. 5 etc., the extended portion 68 is connected to the base portion 66 on the side opposite to the extended portion 67. The extended portion 68 extends from the base portion 66 in the direction opposite to the extended portion 67. The width of the extended portion 68 is narrower than the width of the base portion 66. The extended portion 68 is aligned with the extended portion 65 of the positive electrode bus bar 61P in the X direction. The extended portion 68 constitutes the connector 80. The extended portion 68 is the negative electrode terminal of the connector 80. The connector 80 is configured to include the extended portions 65 and 68 and a part of the case 51. The connector 80 may be referred to as an input terminal block.

[0091] The output bus bar 62 electrically connects the emitter terminal 35E of the upper arm module 30H and the collector terminal 35C of the lower arm module 30L. The output bus bar 62 has a portion that extends in the Z direction away from the capacitor module 50. The plate surface of the output bus bar 62 faces the plate surface of the tip portion 353 of the emitter terminal 35E of the upper arm module 30H and the plate surface of the tip portion 353 of the collector terminal 35C of the lower arm module 30L. And at the location where the plate surfaces face each other, the output bus bar 62 and each of the tip portions 353 are connected.

[0092] The bus bar 60 includes three-phase output bus bars 62. The plate surfaces of the U-phase output bus bar 62(U) and one of the parallel running portions 672 face each other. The plate surfaces of the V-phase output bus bar 62(V) and another one of the parallel running portions 672 face each other. The plate surfaces of the W-phase output bus bar 62(W) and another one of the parallel running portions 672 face each other. Each of the output bus bars 62 straddles (crosses) the second-stage heat exchange portion 41 and the third-stage heat exchange portion 41 in the Z direction. One end of each of the output bus bars 62 protrudes outside from the opening of the case 20 so as to be connectable to the motor generator 3.

[0093] A current sensor 81 is provided in the middle of the output bus bar 62. The current sensor 81 is provided separately for the output bus bar 62. The current sensor 81 detects the phase current. The current sensor 81 is disposed within the case 20.

[0094] As described above, the extended portion 67 of the negative bus bar 61N is provided separately from the base portion 66. Therefore, in the connection (joining) of the bus bar 60, first, as shown in FIG. 12, the bus bar 60 on the lower layer side in the Z direction is connected to the corresponding main terminal 35. Specifically, the extended portion 64 of the positive bus bar 61P is connected to the collector terminal 35C(P) of the upper arm module 30H, and the output bus bar 62 is connected to the emitter terminal 35E(O) of the upper arm module 30H and the collector terminal 35C(O) of the lower arm module 30L.

[0095] Next, as shown in FIG. 13, the bus bar 60 on the upper layer side in the Z direction is connected to the corresponding main terminal 35. Specifically, the extended portion 67 of the negative bus bar 61N is connected to the base portion 66 and also connected to the emitter terminal 35E(N) of the lower arm module 30L. Thereby, the parallel running structure of the negative bus bar 61N and the positive bus bar 61P, and the parallel running structure of the negative bus bar 61N and the output bus bar 62 can be realized.

[0096] <Circuit board> The circuit board 70 includes a wiring board in which wirings are arranged on an insulating base material such as resin, and electronic components (not shown) mounted on the wiring board. The wirings and the electronic components constitute a circuit. The drive circuit 7 described above is configured on the circuit board 70.

[0097] The circuit board 70 is provided with a connector 71 for connection to an external device. The connector 71 includes a housing formed using resin or the like, and terminals held by the housing and mounted on a wiring board. For the sake of simplicity, the terminals are illustrated in a simplified or omitted manner in each figure. When the control circuit is provided outside the power conversion device 4, a drive command for the control circuit is input via the connector 71. When the control circuit is provided on the circuit board 70, a torque request is input from the upper ECU via the connector 71.

[0098] The circuit board 70 is disposed on the opening side of the case 20 in the Z direction. The circuit board 70 is arranged such that the capacitor module 50 and the laminate 45 are positioned between the circuit board 70 and the bottom wall 21 of the case 20. The circuit board 70 is arranged so as to overlap the capacitor module 50 and the laminate 45 in a plan view in the Y direction. Signal terminals 36 of the semiconductor module 30 included in the laminate 45 are inserted and mounted on the circuit board 70. Note that a surface mounting structure may be adopted instead of the insertion mounting. The circuit board 70 has a through hole (not shown) for protruding the output bus bar 62 outside the case 20.

[0099] <Summary of the First Embodiment> FIG. 14 shows the PN current loop in the present embodiment. In considering the inductance of the main circuit, the PN current loop, which is the current path from the collector terminal 35C of the upper arm module 30H, which is the P terminal, to the emitter terminal 35E of the lower arm module 30L, which is the N terminal, is considered. Among the current paths, the path from the collector terminal 35C (P) to the emitter terminal 35E (O) of the upper arm module 30H is indicated by a broken line, and the path from the emitter terminal 35E (O) of the upper arm module 30H to the emitter terminal 35E (N) of the lower arm module 30L is indicated by a solid line. In reality, each semiconductor element 32 is controlled so that the semiconductor elements 32 of the upper arm module 30H and the lower arm module 30L constituting the upper and lower arm circuits 10 do not turn on simultaneously.

[0100] According to the present embodiment, as shown in FIGS. 8 and 14, a plurality of semiconductor modules 30 are divided into an upper arm module 30H and a lower arm module 30L. Then, the upper arm module 30H and the lower arm module 30L are arranged side by side in the Z direction (stacking direction). Thereby, compared with a configuration in which one module provides the upper and lower arm circuits for one phase, and a configuration in which the upper arm module and the lower arm module are arranged side by side in the X direction, the PN current loop can be reduced. When the PN current loop is smaller, the members through which current flows in the reverse direction approach each other, and the magnetic flux cancellation effect is enhanced, so that the inductance can be reduced.

[0101] FIG. 15 shows the arrangement of the semiconductor module 30, the cooler 40, and the capacitor module 50 in the present embodiment. In the present embodiment, as shown in FIG. 15, the capacitor module 50 is arranged in the Z direction with respect to the laminate 45. Then, the power supply bus bar 61 is extended in the Z direction so as to straddle at least one of the heat exchange portions 41 arranged in multiple stages. The length L3 of one stage of the heat exchange portion 41 is sufficiently shorter than the length L4 equal to the diameter of the pipe. Therefore, compared with a configuration in which the capacitor module is arranged beside the laminate in the X direction and the power supply bus bar is extended in the X direction so as to straddle one of the pipes, the length of the power supply bus bar 61 can be shortened. That is, the current path can be shortened.

[0102] By reducing the above-mentioned PN current loop and shortening the length of the power supply bus bar, the power conversion device 4 of the present embodiment can reduce the inductance.

[0103] The arrangement of the positive electrode bus bar 61P and the negative electrode bus bar 61N, which are the power bus bars 61, and the output bus bar 62 is not particularly limited. FIG. 16 shows the current path of the main circuit including the smoothing capacitor 5 and the inverter 6. As shown in FIGS. 9, 10, 16, etc., in this embodiment, the lower arm module 30L is arranged farther from the capacitor module 50 than the upper arm module 30H. As shown in FIGS. 10, 11, 16, etc., the negative electrode bus bar 61N and the positive electrode bus bar 61P extend in the Z direction with their plate surfaces facing each other. The negative electrode bus bar 61N and the output bus bar 62 extend in the Z direction with their plate surfaces facing each other.

[0104] When the bus bars 60 are arranged to face each other in this way, the inductance can be further reduced due to the effect of magnetic flux cancellation. In this embodiment, an example where the negative electrode bus bar 61N faces the positive electrode bus bar 61P and the output bus bar 62 is shown, but it is not limited to this. The negative electrode bus bar 61N may be arranged to face at least one of the positive electrode bus bar 61P and the output bus bar 62.

[0105] In this embodiment, a plurality of upper arm modules 30H constituting the three-phase upper and lower arm circuits 10 are arranged side by side in the X direction orthogonal to the Z direction. Similarly, the lower arm modules 30L are arranged side by side in the X direction. Thereby, in the laminate 45, the semiconductor modules 30 can be arranged in two stages, and the heat exchange section 41 can be arranged in three stages. Therefore, the size of the laminate 45 in the Z direction can be reduced. Also, in all phases, the inductance can be reduced by reducing the PN current loop and shortening the length of the power bus bar. Furthermore, the inductance can be further reduced by the opposed arrangement. That is, it is possible to achieve both downsizing of the size and reduction of the inductance.

[0106] The upper arm module 30H and the lower arm module 30L may be arranged such that the arrangement of the collector terminal 35C and the emitter terminal 35E is the same as each other. In the present embodiment, the lower arm module 30L is arranged so that the front and back surfaces of the semiconductor element 32 are inverted with respect to the upper arm module 30H. As a result, the arrangements of the collector terminal 35C and the emitter terminal 35E are opposite to each other, and it is easy to connect the emitter terminal 35E of the upper arm module 30H and the collector terminal 35C of the lower arm module 30L with the output bus bar 62. That is, the layout of the bus bar 60 can be simplified.

[0107] The shape of the protruding portion of the main terminal 35 is not particularly limited. For example, the entire protruding portion may have a shape extending in the Y direction. In the present embodiment, the protruding portions of the plurality of main terminals 35 each have a bent portion 351. And the plate surface of the tip portion 353, which is the portion on the protruding tip side rather than the bent portion, faces the plate surface of the corresponding bus bar 60. By having the bent portion 351 in this way, the distance to the bus bar 60 to be joined can be shortened, and the inductance can be further reduced. Also, connection processing such as welding can be easily performed. Particularly in the present embodiment, in the protruding portion of each main terminal 35, the length L1 of the root portion 352 is shorter than the length L2 of the tip portion 353. That is, the inductance can be more effectively reduced.

[0108] The extended portion 67 of the negative bus bar 61N may be continuously connected to the base portion 66. In the present embodiment, the extended portion 67 is provided separately from the base portion 66 and integrated by joining. According to this, as shown in FIGS. 12 and 13, before joining the extended portion 67, the positive bus bar 61P and the output bus bar 62, which are the lower layers, can be joined to the corresponding main terminals 35. That is, the joining of the bus bar 60 and the corresponding main terminal 35 becomes easy.

[0109] The extension part 67 may have, for example, a substantially rectangular shape in a plan view in the Y direction so as to integrally cover a part of each of the main terminal 35, the extension part 64 of the negative electrode bus bar 61N, and the output bus bar 62. FIG. 17 shows the current path of the main circuit. FIG. 17 corresponds to FIG. 11. In FIG. 17, as an example, the current path of the U phase is shown. Among the current paths, the solid line arrow indicates the path in the extension part 67 of the negative electrode bus bar 61N, and the broken line arrow indicates the path from the extension part 64 of the positive electrode bus bar 61P to the emitter terminal 35E(N) of the lower arm module 30L.

[0110] As shown in FIGS. 11, 13, 17, etc., the extension part 67 of the negative electrode bus bar 61N of the present embodiment has a slit 671, a parallel running part 672, an opposing part 673, and a connecting part 674. By providing the slit 671 in this way, the current path in the negative electrode bus bar 61N (extension part 67) is restricted. Specifically, current flows along the slit 671. Therefore, as shown in FIG. 17, the parallel running distance in the current path can be lengthened. Thereby, the effect of magnetic flux cancellation can be enhanced, and the inductance can be further reduced. Further, since the slits 671 are adjacent to each other, the connecting part 674 can be easily bent with respect to the other part of the extension part 67 in order to be joined to the emitter terminal 35E(N). That is, the joining of the emitter terminal 35E of the lower arm module 30L and the extension part 67 becomes easy.

[0111] <Modification example> Although an example in which the upper arm module 30H is arranged on the capacitor module 50 side in the Z direction which is the stacking direction has been shown, the present invention is not limited to this. The lower arm module 30L may be arranged on the capacitor module 50 side. In this case, the upper arm module 30H corresponds to the first semiconductor module, and the lower arm module 30L closer to the capacitor module 50 than the upper arm module 30H corresponds to the second semiconductor module. Also, the positive electrode bus bar 61P corresponds to the first power supply bus bar, and the negative electrode bus bar 61N corresponds to the second power supply bus bar.

[0112] When the positive electrode bus bar 61P is used as the first power supply bus bar, the extended portion of the positive electrode bus bar 61P may be arranged to cover at least a part of the protruding portion of the main terminal 35, at least a part of the extended portion of the negative electrode bus bar 61N, and at least a part of the extended portion of the output bus bar 62. The extended portion of the positive electrode bus bar 61P may be provided separately from the base portion. A slit or the like may be provided in the extended portion of the positive electrode bus bar 61P to increase the parallel running distance.

[0113] Although an example in which a plurality of upper arm modules 30H and lower arm modules 30L are provided has been shown, the present invention is not limited to this. For example, by sharing the sealing body 31 so as to integrally seal the three-phase semiconductor elements 32, the three-phase upper arm 10H may be provided by one upper arm module 30H. Similarly, the three-phase lower arm 10L may be provided by one lower arm module 30L.

[0114] (Second Embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be incorporated. In the preceding embodiment, one semiconductor element 32 constituted one arm 10H, 10L. Instead of this, a plurality of semiconductor elements 32 may be connected in parallel to each other to constitute one arm 10H, 10L.

[0115] FIG. 18 is a diagram showing a circuit configuration of the power conversion device 4 according to the present embodiment. FIG. 19 is a perspective view showing the semiconductor module 30. FIG. 19 corresponds to FIG. 6 and shows an upper arm module 30H as an example.

[0116] As shown in FIG. 18, in the power conversion device 4 of the present embodiment, each arm 10H, 10L of the upper and lower arm circuits 10 constituting the inverter 6 is constituted by two IGBTs 12 connected in parallel. The two IGBTs 12 connected in parallel are controlled by a gate drive signal in which the high level and the low level are switched at the same timing. The FWD 13 is connected in anti-parallel to each of the IGBTs 12.

[0117] As shown in FIG. 19, the semiconductor module 30 includes two semiconductor elements 32. In each semiconductor element 32, an RC-IGBT is formed as in the previous embodiment. The two semiconductor elements 32 are arranged side by side in the X direction. The collector electrodes 32C of the two semiconductor elements 32 are electrically connected to a common collector terminal 35C via a surface metal body 332 (wiring portion 334). The emitter electrodes 32E of the two semiconductor elements 32 are electrically connected to a common emitter terminal 35E via a surface metal body 342 (wiring portion 344).

[0118] <Summary of the Second Embodiment> The power conversion device 4 of this embodiment is the same as the configuration of the power conversion device 4 shown in the previous embodiment except that the semiconductor module 30 includes a plurality of semiconductor elements 32. A stacked body 45 is constituted by a three-stage arranged heat exchange part and a two-stage arranged semiconductor module 30. The upper arm module 30H and the lower arm module 30L are arranged side by side in the Z direction. Any of the configurations shown in the previous embodiment and its modifications can be applied to the power conversion device 4 of this embodiment. Therefore, the power conversion device 4 of this embodiment can achieve the same effects as the power conversion device 4 of the previous embodiment.

[0119] <Modification Example> The number of switching elements constituting one arm 10H, 10L is not limited to two. Three or more may be used. The number of semiconductor elements 32 included in the semiconductor module 30 is not limited to two. Three or more may be used.

[0120] (Third Embodiment) This embodiment is a modification example based on the previous embodiment, and the description of the previous embodiment can be incorporated by reference. In the second embodiment, a parallel circuit of one arm 10H, 10L is provided by one semiconductor module 30. Instead of this, a parallel circuit may be provided by a plurality of semiconductor modules 30.

[0121] FIG. 20 shows the arrangement of the laminate 45 and the bus bar 60 in the power conversion device 4 according to the present embodiment. FIG. 20 corresponds to FIG. 11. FIG. 21 shows the state before arranging the extension portion 67 of the negative bus bar 61N, and FIG. 22 shows the state after arranging the extension portion 67. FIGS. 21 and 22 correspond to FIGS. 12 and 13. In FIGS. 21 and 22, for the sake of convenience, the extension portions 65 of the positive bus bar 61P and the extension portion 68 of the negative bus bar 61N are omitted.

[0122] In the present embodiment, each semiconductor module 30 has the same configuration as that in the first embodiment (see FIGS. 6 and 7). That is, one semiconductor module 30 includes one semiconductor element 32. Although not shown, each arm 10H, 10L of the upper and lower arm circuits 10 is configured by connecting three IGBTs 12 in parallel.

[0123] As shown in FIGS. 20 to 22, the laminate 45 includes semiconductor modules 30 arranged in six stages and a heat exchange portion 41 arranged in seven stages. The three semiconductor modules 30 on the side closer to the capacitor module 50 in the Z direction are the upper arm modules 30H, and the three semiconductor modules 30 on the far side are the lower arm modules 30L. The upper arm modules 30H are arranged in the X direction in the order of U phase, V phase, and W phase at each stage. The extension portion 64 of the positive bus bar 61P extends in the Z direction and is electrically connected to the three collector terminals 35C(P) of the corresponding phase.

[0124] The lower arm modules 30L are also arranged in the X direction in the order of U phase, V phase, and W phase at each stage. The output bus bar 62 extends in the Z direction and is electrically connected to the main terminals 35 of the corresponding phase, specifically, the emitter terminal 35E(O) of the upper arm module 30H and the collector terminal 35C(O) of the lower arm module 30L.

[0125] The extended portion 67 of the negative electrode bus bar 61N has a slit 671, a parallel running portion 672, an opposing portion 673, and a connecting portion 674, similar to the previous embodiment. The slit 671 is provided between the upper arm module 30H and the lower arm module 30L in each phase. The slit 671 is provided between the collector terminal 35C(P) and the emitter terminal 35E(N). The parallel running portion 672 is provided so as to overlap with the connection portion of the main terminal 35 on the output bus bar 62 in a plan view in the Z direction so that the output bus bar 62 and the plate surfaces face each other. The opposing portion 673 extends in the X direction from the parallel running portion 672 and is provided so as to overlap with the extended portion 64 of the positive electrode bus bar 61P. The connecting portion 674 extends in the X direction from the parallel running portion 672 and is electrically connected to the emitter terminal 35E(N) of the lower arm module 30L.

[0126] As described above, in this embodiment, three upper arm modules 30H of the same phase are connected in parallel by the bus bars 61P and 62. Three lower arm modules 30L of the same phase are connected in parallel by the bus bars 61N and 62.

[0127] As shown in FIGS. 21 and 22, the extended portion 67 of this embodiment is also provided separately from the base portion 66. In the connection (joining) of the bus bar 60, first, as shown in FIG. 21, the bus bar 60 on the lower layer side in the Z direction is connected to the corresponding main terminal 35. Specifically, the extended portion 64 of the positive electrode bus bar 61P is connected to the collector terminal 35C(P) of the upper arm module 30H, and the output bus bar 62 is connected to the emitter terminal 35E(O) of the upper arm module 30H and the collector terminal 35C(O) of the lower arm module 30L.

[0128] Next, as shown in FIG. 22, the bus bar 60 on the upper layer side in the Z direction is connected to the corresponding main terminal 35. Specifically, the extended portion 67 of the negative electrode bus bar 61N is connected to the base portion 66 and also connected to the emitter terminal 35E(N) of the lower arm module 30L. Thereby, a parallel running structure between the negative electrode bus bar 61N and the positive electrode bus bar 61P, and a parallel running structure between the negative electrode bus bar 61N and the output bus bar 62 can be realized.

[0129] <Summary of the Third Embodiment> The power conversion device 4 of this embodiment is the same as the configuration of the power conversion device 4 shown in the first embodiment, except that a plurality of semiconductor modules 30 are connected in parallel by a bus bar 60. For example, also in this embodiment, the plurality of semiconductor modules 30 are divided into an upper arm module 30H and a lower arm module 30L, and the upper arm module 30H and the lower arm module 30L are arranged side by side in the Z direction. Thereby, the PN current loop can be reduced. Also, the capacitor module 50 is arranged in the Z direction with respect to the laminate 45. And the power supply bus bar 61 is extended in the Z direction so as to straddle at least one of the heat exchange parts 41 arranged in multiple stages. Thereby, the length of the power supply bus bar 61 can be shortened. Therefore, the inductance can be reduced.

[0130] The configuration described in this embodiment can be combined with any of the configurations of the first embodiment and its modified examples.

[0131] <Modified Example> The number of switching elements constituting one arm 10H, 10L is not limited to three. Two may be used, or four or more may be used. The number of semiconductor modules 30 is not limited to three. Two may be used, or four or more may be used.

[0132] (Other Embodiments) The disclosure in this specification, drawings, etc. is not limited to the illustrated embodiments. The disclosure includes the illustrated embodiments and modifications by those skilled in the art based thereon. For example, the disclosure is not limited to the combination of parts and / or elements shown in the embodiments. The disclosure can be implemented by various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure includes those in which parts and / or elements of the embodiments are omitted. The disclosure includes the replacement or combination of parts and / or elements between one embodiment and another. The technical scope disclosed is not limited to the description of the embodiments. Some of the technical scopes disclosed are indicated by the description of the claims and should be construed to include all changes within the meaning and scope equivalent to the description of the claims.

[0133] The disclosure in the specification, drawings, etc. is not limited by the description of the claims. The disclosure in the specification, drawings, etc. includes the technical idea described in the claims and extends to more diverse and extensive technical ideas than the technical idea described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being restricted by the description of the claims.

[0134] When an element or layer is referred to as "above", "connected to", "attached to", or "coupled to", it may be directly above, connected to, attached to, or coupled to another element or layer, and there may also be intervening elements or intervening layers. In contrast, when an element is referred to as "directly above", "directly connected to", "directly attached to", or "directly coupled to" another element or layer, there are no intervening elements or intervening layers. Other words used to describe the relationship between elements should be interpreted 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.

[0135] Spatially relative terms such as "inside", "outside", "beneath", "below", "lower", "above", "upper", etc. are used herein to facilitate description of the relationship of one element or feature to another element or feature as illustrated. Spatially relative terms can be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the drawings. For example, if the device in the figures is turned over, an element described as "below" or "beneath" another element or feature would then be oriented "above" the other element or feature. Thus, the term "below" can encompass both an orientation of above and below. The device may be oriented in other directions (rotated 90 degrees or other orientations), and the spatially relative descriptors used in this specification are to be interpreted accordingly.

[0136] The drive system 1 of the vehicle is not limited to the above-described configuration. For example, although an example having one motor generator 3 is shown, it is not limited thereto. A plurality of motor generators may be provided.

[0137] Although an example in which the power conversion device 4 includes the inverter 6 as a power conversion circuit has been shown, the present invention is not limited thereto. For example, a configuration including a plurality of inverters may be used. A configuration including at least one inverter and a converter may be used. Only a converter may be provided. The technical idea grasped from the embodiments and modifications described so far is described below as an appendix. <Appendix 1> A plurality of semiconductor modules (30) including an upper arm module (30H) constituting the upper arm (10H) of the upper and lower arm circuit (10), and a lower arm module (30L) constituting the lower arm (10L) of the upper and lower arm circuit and arranged side by side in the stacking direction with the upper arm module; A cooler (40) having a plurality of heat exchange parts (41) arranged in multiple stages so as to cool each of the upper arm module and the lower arm module from both sides in the stacking direction, and forming a stacked body (45) together with the plurality of semiconductor modules; A capacitor (50) arranged on one end side of the stacked body in the stacking direction; A plurality of bus bars (60) including a power supply bus bar (61) that electrically connects the capacitor and the semiconductor module and extends in the stacking direction so as to straddle at least one of the heat exchange parts; The power supply bus bar includes a positive electrode bus bar (61P) that electrically connects the positive electrode of the capacitor and the upper arm module, and a negative electrode bus bar (61N) that electrically connects the negative electrode of the capacitor and the lower arm module; The plurality of bus bars electrically connect the upper arm module and the lower arm module, and include an output bus bar (62) that extends in a direction away from the capacitor in the stacking direction, a power conversion device. <Appendix 2> One of the upper arm module and the lower arm module, the first semiconductor module, is farther from the capacitor in the stacking direction than the other, the second semiconductor module. A first power bus bar which is the power bus bar connected to the first semiconductor module, and at least one of a second power bus bar which is the power bus bar connected to the second semiconductor module and the output bus bar face each other in a plate surface and extend in the stacking direction, the power conversion device according to Supplementary Note 1. <Supplementary Note 3> The plurality of semiconductor modules each have a semiconductor element (32), a sealing body (31) for sealing the semiconductor element, and a plurality of main terminals (35) which are electrically connected to the semiconductor element, protrude from the sealing body to the outside, and are connected to the corresponding bus bar. The plurality of main terminals include a first main terminal (35E) connected to the surface of the semiconductor element in the stacking direction and a second main terminal (35C) connected to the back surface of the semiconductor element. In the common semiconductor module, a protruding portion of the first main terminal and a protruding portion of the second main terminal are arranged side by side in a direction orthogonal to the stacking direction, the power conversion device according to Supplementary Note 2. <Supplementary Note 4> The plurality of semiconductor modules include a plurality of upper arm modules and a plurality of lower arm modules that constitute the multiphase upper and lower arm circuits. Each of the plurality of upper arm modules and the plurality of lower arm modules is arranged side by side in the one direction, the power conversion device according to Supplementary Note 3. <Supplementary Note 5> The lower arm module is arranged such that the front and back surfaces of the semiconductor element are inverted with respect to the upper arm module, and the arrangement of the first main terminal and the second main terminal is opposite to that of the upper arm module, the power conversion device according to Supplementary Note 3 or Supplementary Note 4. <Supplementary Note 6> The protruding portions of the plurality of main terminals each have a bent portion (351). The plate surface of the portion on the protruding tip side from the bent portion faces the plate surface of the corresponding bus bar, the power conversion device according to Supplementary Note 3 or Supplementary Note 4. <Supplementary Note 7> In the protruding portion of each main terminal, the length from the end on the sealing body side to the bent portion is shorter than the length from the bent portion to the protruding tip, the power conversion device according to Supplementary Note 6. <Supplementary Note 8> The first power bus bar has a base portion (66) connected to the capacitor and an extended portion (67) connected to the base portion and including a portion extending in the stacking direction. The extended portion of the first power bus bar is arranged to cover at least a part of the protruding portion of the main terminal, at least a part of the extended portion of the second power bus bar in the stacking direction, and at least a part of the extended portion of the output bus bar in the stacking direction. The power conversion device according to Appendix 3 or Appendix 4. <Appendix 9> The extended portion of the first power bus bar includes a slit (671) provided between the upper arm module and the lower arm module in the stacking direction, a parallel running portion (672) adjacent to the slit in the one direction and parallel to the extended portion of the output bus bar in the stacking direction, a facing portion (673) adjacent to the slit on the capacitor side in the stacking direction and extending from the parallel running portion in the one direction to face the second power bus bar, and a connecting portion (674) adjacent to the slit on the side opposite to the facing portion in the stacking direction and extending from the parallel running portion in the one direction to be connected to the corresponding main terminal. The power conversion device according to Appendix 8.

Claims

1. An upper arm module (30H) that constitutes an upper arm (10H) of an upper and lower arm circuit (10), a lower arm module (30L) that constitutes a lower arm (10L) of the upper and lower arm circuit, and is arranged side by side with the upper arm module in the stacking direction, and a plurality of semiconductor modules (30) including the same; A cooler (40) having a plurality of heat exchange parts (41) that are arranged in multiple stages so as to cool each of the upper arm module and the lower arm module from both sides in the stacking direction, and form a stacked body (45) together with the plurality of semiconductor modules; A capacitor (50) arranged on one end side of the stacked body in the stacking direction; A plurality of bus bars (60) including a power supply bus bar (61) that electrically connects the capacitor and the semiconductor module and extends in the stacking direction so as to straddle at least one of the heat exchange parts; The power supply bus bar includes a positive electrode bus bar (61P) that electrically connects the positive electrode of the capacitor and the upper arm module, and a negative electrode bus bar (61N) that electrically connects the negative electrode of the capacitor and the lower arm module; The plurality of bus bars electrically connect the upper arm module and the lower arm module, and include an output bus bar (62) that extends in a direction away from the capacitor in the stacking direction; The cooler has an introduction pipe (42) that is connected to each of the heat exchange parts and introduces a refrigerant into the heat exchange part, and a discharge pipe (43) that is connected to each of the heat exchange parts and discharges the refrigerant that has flowed through the heat exchange part; A power conversion device in which the introduction pipe is connected to one end side of the plurality of heat exchange parts and the discharge pipe is connected to the other end side of the plurality of heat exchange parts in a direction orthogonal to the stacking direction.

2. The power conversion device according to Claim 1, wherein the introduction pipe and the discharge pipe extend in a direction away from the capacitor in the stacking direction from the cooler.

3. A power supply connector (80) for connecting to a DC power supply is provided, The power conversion device according to Claim 1, wherein the power supply connector is arranged such that the capacitor is located between the power supply connector and the stacked body in the stacking direction.

4. A signal connector (71) that is connected to an external device and to which a signal for driving the plurality of semiconductor modules is input is provided, The power conversion device according to claim 1, wherein the signal connector is arranged alongside the laminate in the one direction.

5. The power conversion device according to claim 1, comprising a case (20) that houses the laminate, the capacitor, and the bus bar.

6. The power conversion device according to claim 1, wherein the capacitor has a plurality of capacitor elements (52).

7. The power conversion device according to claim 1, comprising a current sensor (81) provided for the output bus bar.

8. A circuit for driving the semiconductor module is configured, and a circuit board (70) housed in the case is provided. The power conversion device according to claim 5, wherein the circuit board is arranged on the opening side of the case such that the laminate and the capacitor are positioned between the circuit board and the bottom wall (21) of the case having an opening on one side.

9. The power conversion device according to claim 1, wherein the semiconductor module has a semiconductor element (32) in which an RC-IGBT is formed.

10. The power conversion device according to claim 1, wherein the semiconductor module has a semiconductor element (32) in which a MOSFET is formed.

11. The power conversion device according to claim 5, wherein the output bus bar protrudes to the outside from the opening of the case having an opening on one side.

12. The power conversion device according to claim 1, comprising a pressurizing member (46) having a pressurizing plate (461) that holds the laminate in a pressed state between the laminate and the capacitor.

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