CN118120140A

CN118120140A - Power conversion device

Info

Publication number: CN118120140A
Application number: CN202280068787.8A
Authority: CN
Inventors: 松冈哲矢; 桥本雄太; 小泽朋树; 竹内和哉; 髙井信次; 清水贤宏
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2021-10-15
Filing date: 2022-09-28
Publication date: 2024-05-31

Abstract

A power conversion apparatus comprising: a housing (20); a semiconductor module (30); a first cooler (40) for cooling the semiconductor module (30) from one surface side; a second cooler (50) for cooling from the back side; and a connecting pipe (60) connecting the flow path (41) of the first cooler (40) and the flow path (51) of the second cooler (50). The flow rate of the refrigerant (80) is varied between the flow paths (41, 51), and the cross-sectional area of the flow path (41) having a large flow rate is made larger than the cross-sectional area of the flow path (51) having a small flow rate. The first cooler (40) having a wide flow path (41) is configured by a part of the case (20) accommodating the semiconductor module (30), and the second cooler (50) having a narrow flow path (51) is accommodated in the case (20) together with the semiconductor module (30).

Description

Power conversion device

Citation of related application

The present application is based on patent application numbers 2021-169737 of the japanese filed application at 10/15/2021 and patent application numbers 2022-146481 of the japanese filed application at 9/14/2022, the contents of which are incorporated by reference in their entirety.

Technical Field

The disclosure in the present specification relates to a power conversion apparatus.

Background

Patent document 1 discloses a power conversion device. The power conversion device includes: a power module; two cooling channel forming bodies (coolers) disposed so as to sandwich the power module; and an intermediate pipe connecting the flow paths of the two coolers. The contents of the prior art documents are incorporated by reference as if set forth in the specification as technical elements.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2019-68533

Disclosure of Invention

In patent document 1, it is considered that the cooler is thinned in the stacking direction in order to miniaturize the power conversion device in the stacking direction of the power module and the cooler, that is, to reduce the height. However, the flow path becomes narrow, and the pressure loss increases. In the above-described viewpoints or other viewpoints not mentioned, further improvements are demanded for the power conversion apparatus.

It is an object of the present disclosure to provide a power conversion device capable of reducing the height while suppressing an increase in pressure loss.

The power conversion device disclosed herein includes: a semiconductor module that constitutes a power conversion circuit; a housing having a first wall portion in which the semiconductor module is disposed and a second wall portion which is connected to the first wall portion and forms an accommodating space together with the first wall portion, the semiconductor module being disposed in the accommodating space;

A first cooler configured to cool the semiconductor module, the first cooler including a first wall portion and a first flow path formed inside the first wall portion and through which a refrigerant flows;

A second cooler having a second flow path through which a refrigerant flows, the second cooler being disposed in the accommodation space on the semiconductor module and cooling the semiconductor module from a side opposite to the first cooler; and

A connection portion having a connection flow path communicating with the first flow path and the second flow path,

The flow rate of the refrigerant flowing in the first flow path is greater than the flow rate of the refrigerant flowing in the second flow path,

The cross-sectional area of the first flow path is greater than the cross-sectional area of the second flow path.

According to the disclosed power conversion device, the flow rate of the refrigerant is made different between the first flow path and the second flow path, and the cross-sectional area of the first flow path having a large flow rate is made larger than the cross-sectional area of the second flow path. That is, the second flow path having a smaller flow rate is narrowed, and the first flow path having a larger flow rate is widened. The first cooler having a wide flow path is formed by a part of a case accommodating the semiconductor module, and the second cooler having a narrow flow path is accommodated in the case together with the semiconductor module. As a result, it is possible to provide a power conversion device capable of reducing the height while suppressing an increase in pressure loss.

The various modes disclosed in the present specification adopt mutually different technical means to achieve the respective purposes. The claims and any symbols in parentheses in the claims are exemplary and intended to indicate correspondence with portions of the embodiments described below, and are not intended to limit the technical scope. The objects, features and effects disclosed in the present specification can be more clearly understood with reference to the following detailed description and the accompanying drawings.

Drawings

Fig. 1 is a diagram showing a circuit configuration and a driving system of a power conversion device of a first embodiment.

Fig. 2 is a plan view showing the power conversion device.

Fig. 3 is a cross-sectional view taken along line ii-ii of fig. 2.

Fig. 4 is a cross-sectional view taken along line IV-IV of fig. 2.

Fig. 5 is a diagram showing the effect of the second cooler.

Fig. 6 is a cross-sectional view showing a modification.

Fig. 7 is a cross-sectional view showing a power conversion device of a second embodiment.

Fig. 8 is a diagram showing a configuration of fins in the first cooler.

Fig. 9 is a plan view showing a power conversion device according to a third embodiment.

Fig. 10 is a cross-sectional view taken along line X-X of fig. 9.

Fig. 11 is a diagram showing a circuit configuration of the power conversion device of the fourth embodiment.

Fig. 12 is a plan view showing the power conversion device.

Fig. 13 is a cross-sectional view taken along line XI ii-XI ii of fig. 12.

Fig. 14 is a cross-sectional view taken along line XIV-XI V of fig. 12.

Fig. 15 is a cross-sectional view showing a power conversion device of a fifth embodiment.

Fig. 16 is a cross-sectional view showing a modification.

Detailed Description

Hereinafter, a plurality of embodiments will be described with reference to the drawings. In the respective embodiments, the same reference numerals are given to the corresponding constituent elements, and overlapping description may be omitted. In the case where only a part of the structure is described in each embodiment, the structure of the other embodiment described above can be applied to other parts of the structure. In addition, not only the combination of the structures explicitly described in the description of each embodiment, but also the structures of the plurality of embodiments may be partially combined with each other unless explicitly described, as long as the combination is not particularly hindered.

The power conversion device of the present embodiment is applied to a moving object using a rotating electric machine as a driving source, for example. Examples of the mobile object include an electric vehicle such as an electric vehicle (BEV), a Hybrid Electric Vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), an aircraft such as an unmanned aerial vehicle or an electric vertical takeoff and landing machine (eVTOL), a ship, a construction machine, and an agricultural machine. Hereinafter, an example applied to a vehicle will be described.

(First embodiment)

First, a schematic configuration of a drive system of a vehicle will be described based on fig. 1.

< Drive System of vehicle >)

As shown in fig. 1, a drive system 1 of a vehicle includes a direct-current power supply 2, a motor generator 3, and a power conversion device 4.

The dc power supply 2 is a dc voltage source constituted by a chargeable/dischargeable secondary battery. The secondary battery is, for example, a lithium ion battery, a nickel hydrogen battery, an organic radical battery, or the like. The motor generator 3 is a three-phase ac type rotating electrical machine. The motor generator 3 functions as a motor that is a driving source for running the vehicle. The motor generator 3 functions as a generator during regeneration. The power conversion device 4 converts power between the dc power supply 2 and the motor generator 3.

Circuit structure of power conversion device

Fig. 1 shows a circuit configuration of the power conversion device 4. The power conversion device 4 includes at least a power conversion circuit. The power conversion circuit of the present embodiment is an inverter 5. The power conversion device 4 may further include a smoothing capacitor 6, a driving circuit 7, and the like.

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

The inverter 5 is a DC-AC conversion circuit. The inverter 5 converts a dc voltage into a three-phase ac voltage according to switching control of a control circuit, not shown, and outputs the three-phase ac voltage to the motor generator 3. Thereby, the motor generator 3 is driven to generate a predetermined torque. The inverter 5 converts the three-phase ac voltage generated by the motor generator 3 receiving the rotational force from the wheels at the time of regenerative braking of the vehicle into a dc voltage according to the switching control of the control circuit, and outputs the dc voltage to the P line 8. In this way, the inverter 5 performs bidirectional power conversion between the dc power supply 2 and the motor generator 3.

The inverter 5 is configured to include upper and lower arm circuits 10 corresponding to three phases. The upper and lower arm circuits 10 are sometimes referred to as bridge branches. The upper and lower arm circuits 10 have an upper arm 10H and a lower arm 10L, respectively. The upper arm 10H and the lower arm 10L set the upper arm 10H to the P line 8 side, and are connected in series between the P line 8 and the N line 9.

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

The upper and lower arm circuits 10 (10U, 10V, 10W) have a series circuit 12. The series circuit 12 of the upper and lower arm circuits 10 may be one or a plurality of. In many cases, the series circuits 12 are connected in parallel with each other to constitute an upper and lower arm circuit 10 corresponding to one. In the present embodiment, each of the upper and lower arm circuits 10 has one series circuit 12. The series circuit 12 is configured by connecting a switching element on the upper arm 10H side and a switching element on the lower arm 10L side in series between the P line 8 and the N line 9.

The number of switching elements on the high side and the switching elements on the low side constituting the series circuit 12 is not particularly limited. One or a plurality of the above-mentioned materials may be used. The series circuit 12 of the present embodiment has two switching elements on the high side and two switching elements on the low side. The two switching elements on the high side are connected in parallel, and the two switching elements on the low side are connected in parallel, thereby constituting one series circuit 12. That is, the six arms 10H and 10L of the upper and lower arm circuits 10 corresponding to the three phases are each constituted by two switching elements connected in parallel to each other.

In the present embodiment, an n-channel MOSFET 13 is used as each switching element. The MOSFET is an abbreviation for power field effect transistor (Meta l Ox i de Semi conductor F I E L D EFFECT TRANS I stor). The two MOSFETs 13 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 two MOSFETs 13 on the low side connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage).

A diode 14 for reflow (hereinafter, referred to as FWD 14) is connected in anti-parallel to each of the MOSFETs 13. In the case of the MOSFET 13, the FWD 14 may be a parasitic diode (body diode) or an external diode. In the upper arm 10H, the drain of the MOSFET 13 is connected to the P line 8. In the lower arm 10L, the source of the MOSFET 13 is connected to the N line 9. Further, the drain of the MOSFET 13 in the upper arm 10H and the drain of the MOSFET 13 in the lower arm 10L are connected to each other. The anode of the FWD 14 is connected to the source of the corresponding MOSFET 13, and the cathode is connected to the drain.

The switching element is not limited to the MOSFET 13. For example, GBT may also be employed. I GBT is an abbreviation for insulated gate bipolar transistor (I nsu L ATED GATE B I po L AR TRANS I stor). In the case of GBT, the FWDs 14 are also connected in anti-parallel.

The driving circuit 7 drives switching elements constituting a power conversion circuit such as the inverter 5. The driving circuit 7 supplies a driving voltage to the gate of the corresponding MOSFET 13 based on a driving instruction of the control circuit. The driving circuit drives the corresponding MOSFET 13, i.e., on-driving and off-driving, by applying a driving voltage. The drive circuit is sometimes referred to as a driver.

The power conversion device 4 may include a control circuit of the switching element. The control circuit generates a drive command for operating the MOSFET 13, and outputs the drive command to the drive circuit 7. The control circuit generates a drive command based on, for example, a torque request input from a host ECU not shown and signals detected by various sensors. The ECU is an abbreviation for electronic control unit (E l ectron ic Contro l Un it). The control circuit may be provided in the host ECU.

As various sensors, there are, for example, a current sensor, a rotation angle sensor, and a voltage sensor. The power conversion device 4 may also include at least one of the sensors. The current sensor detects a 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 6. The control circuit is configured to include a processor and a memory, for example. The control circuit outputs, for example, a PWM signal as a driving instruction. PWM is an acronym for pulse width modulation (Pu l se Width Modu l at ion).

The power conversion device 4 may include a converter as a power conversion circuit. The converter is a DC-DC conversion circuit that converts a direct-current voltage into a direct-current voltage of a different value. The converter is arranged between the direct current power supply 2 and the smoothing capacitor 6. The converter includes, for example, a reactor and the upper and lower arm circuits 10 described above. According to this configuration, the voltage can be increased and decreased. 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 arranged between the dc power supply 2 and the converter.

Structure of Power conversion device

Fig. 2 is a plan view showing the power conversion device 4 according to the present embodiment. In fig. 2, a part of elements such as a cover and a circuit board are omitted in order to know the arrangement of the semiconductor module and the cooler. Fig. 3 is a cross-sectional view taken along line ii-ii of fig. 2. Fig. 4 is a cross-sectional view taken along line I V-IV of fig. 3. The cover and the circuit substrate are also omitted in fig. 4. The blank arrows of fig. 2 and 4 indicate the flow direction of the refrigerant.

The power conversion device 4 of the present embodiment includes a housing 20, a semiconductor module 30, a first cooler 40, a second cooler 50, and a connecting pipe 60. As shown in fig. 3, the power conversion device 4 may include a circuit board 70.

Hereinafter, the arrangement direction of the semiconductor modules 30 is referred to as the X direction. The stacking direction of the semiconductor module 30, the first cooler 40, and the second cooler 50 orthogonal to the X direction is referred to as the Z direction. The direction orthogonal 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 in a mutually orthogonal positional relationship. A plan view from the Z direction may be simply referred to as a plan view.

< Shell >

The case 20 accommodates other elements constituting the power conversion device 4. The case 20 is a molded body formed by, for example, aluminum die casting. The case 20 has an opening for accommodating other elements. The housing 20 has a first wall portion and a second wall portion that is connected to the first wall portion and forms an accommodation space 20S together with the first wall portion. For example, in the case 20 having a box shape with one surface opened, the bottom wall may be a first wall portion and the side wall may be a second wall portion. The cylindrical side wall may be the second wall portion, and the partition wall that partitions the space in the cylinder may be the first wall portion.

The case 20 of the present embodiment has a box shape with one surface opened. The case 20 has a substantially rectangular shape in a plan view in the Z direction. The housing 20 has a bottom wall 21 and side walls 22. The semiconductor module 30, the second cooler 50, the circuit board 70, and the like are disposed in the accommodation space 20S of the case 20.

The side wall 22 is provided with an introduction pipe 23 for supplying the refrigerant to the first cooler 40 and the second cooler 50, and a discharge pipe 24 for discharging the refrigerant from the first cooler 40 and the second cooler 50. The introduction pipe 23 and the discharge pipe 24 are inserted into corresponding through holes (not shown) and pass through the inside and outside of the housing 20. The introduction pipe 23 and the discharge pipe 24 each include a portion extending in the Y direction. The introduction pipe 23 and the discharge pipe 24 are attached to the common side wall 22, for example.

As shown in fig. 3, the power conversion device 4 may include a cover 25 (lid) that closes the opening of the housing 20. The housing 20 and the cover 25 are sometimes referred to as a frame.

Semiconductor Module

The semiconductor module 30 constitutes the inverter 5 (power conversion circuit) which is the upper and lower arm circuit 10. The power conversion device 4 of the present embodiment includes three semiconductor modules 30. A semiconductor module 30 provides a series circuit 12, i.e., with a corresponding upper and lower arm circuit 10. The plurality of semiconductor modules 30 includes a semiconductor module 30U constituting the upper and lower arm circuits 10U, a semiconductor module 30V constituting the upper and lower arm circuits 10V, and a semiconductor module 30W constituting the upper and lower arm circuits 10W.

All the semiconductor modules 30 have a structure common to each other. Each semiconductor module 30 includes a semiconductor element 31, a sealing body 32, a signal terminal 33, and the like. The semiconductor element 31 includes a switching element formed on a semiconductor substrate made of silicon (S i), 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 a thickness direction of the semiconductor substrate. As the wide band gap semiconductor, for example, silicon carbide (S iC), gallium nitride (GaN), gallium oxide (Ga ₂O₃), and diamond are available. The semiconductor element 31 is sometimes referred to as a power element, a semiconductor chip, or the like.

The semiconductor element 31 of the present embodiment includes the n-channel MOSFET 13 and the FWD 14 described above formed on a semiconductor substrate made of S iC. The MOSFET 13 has a vertical structure such that a main current flows in a plate thickness direction of the semiconductor element 31 (semiconductor substrate). The semiconductor element 31 has main electrodes, not shown, on both sides in the plate thickness direction. Specifically, the main electrode of the switching element has a source on the front surface and a drain on the back surface. The source is formed on a portion of the surface. The drain electrode is formed in substantially the entire region of the back surface.

A main current flows between the drain and the source. The semiconductor element 31 has a pad, not shown, as an electrode for a signal on a source electrode formation surface. The semiconductor element 31 is disposed such that the plate thickness direction thereof is substantially parallel to the Z direction. The semiconductor element 31 of the present embodiment includes: two semiconductor elements 31H providing switching elements on the high side of the series circuit 12; and two semiconductor elements 31L providing switching elements on the low side of the series circuit 12. The semiconductor elements 31H and 31L are arranged in the Y direction. The two semiconductor elements 31H are arranged in the X direction. Similarly, the two semiconductor elements 31L are arranged in the X direction.

The four semiconductor elements 31 provide four switching elements of one series circuit 12. The semiconductor module 30 includes semiconductor elements 31 corresponding to the number of switching elements constituting one series circuit 12. In the case where there are two switching elements constituting the series circuit 12, the semiconductor module 30 includes one semiconductor element 31H, 31L, respectively.

The sealing body 32 seals a part of other elements constituting the semiconductor module 30. The remainder of the other elements are exposed to the outside of the sealing body 32. The sealing body 32 is made of, for example, resin. The sealing body 32 is formed by transfer molding using, for example, an epoxy resin as a material. The sealing body 32 may be formed using, for example, gel.

The sealing body 32 has a substantially rectangular shape in plan view, for example. As the surface forming the outer contour, the sealing body 32 has one surface 32a and a back surface 32b which is a surface opposite to the one surface 32a in the Z direction. The face 32a and the back face 32b are, for example, flat faces. The rear surface 32b is connected to the front surface 32a, and the side surfaces 32c, 32d, 32e, and 32f are provided. The side face 32c is a face opposite to the side face 32d in the Y direction. The side face 32e is a face opposite to the side face 32f in the X direction.

The signal terminals 33 are external connection terminals electrically connected to the pads of the semiconductor element 31. The signal terminal 33 protrudes from the sealing body 32 to the outside. For example, the signal terminals 33 connected to the pads of the semiconductor element 31H protrude from the side surfaces 32c of the sealing body 32. The signal terminals 33 connected to the pads of the semiconductor element 31L protrude from the side surface 32d of the sealing body 32.

The semiconductor module 30 includes main terminals or wiring members, not shown, in addition to the above elements. The main terminal is an external connection terminal electrically connected to the main electrode of the semiconductor element 31. The main terminals include a P terminal, an N terminal, and an output terminal. The P terminal is electrically connected to the drain of the semiconductor element 31H. The N terminal is electrically connected to the source of the semiconductor element 31L. The P terminal and the N terminal are sometimes referred to as power terminals. The output terminal is electrically connected to a connection point (midpoint) between the source of the semiconductor element 31H and the drain of the semiconductor element 31L, that is, a connection point (midpoint) of the series circuit 12. For example, the P terminal and the N terminal protrude outward from the side surface 32c of the sealing body 32, and the output terminal protrudes outward from the side surface 32d of the sealing body 32. That is, the external connection terminals do not protrude from the side surfaces 32e, 32 f.

The wiring member provides a wiring function of electrically connecting the main electrode and the main terminal of the semiconductor element 31. The wiring member provides a heat radiation function for radiating heat of the semiconductor element 31. The wiring member is disposed so as to sandwich the semiconductor element 31 in the Z direction, for example. As the wiring member, a substrate having a metal body disposed on both surfaces of an insulating base material may be used, or a heat sink may be used as the metal member. The heat spreader is provided, for example, as part of a leadframe. By exposing a part of the wiring member from at least one of the front surface 32a and the rear surface 32b of the sealing body 32, heat dissipation can be improved.

The semiconductor module 30 is disposed on the bottom wall 21 such that the back surface 32b faces the inner surface of the bottom wall 21. An electrical insulating member such as a ceramic plate is disposed between the semiconductor module 30 and the bottom wall 21 of the housing 20, as necessary. As shown in fig. 2, three semiconductor modules 30 are arranged in the X direction. That is, the plurality of semiconductor modules 30 are arranged laterally in the X direction. The three semiconductor modules 30 are arranged in the order of the semiconductor module 30U, the semiconductor module 30V, and the semiconductor module 30W, for example.

In the X direction, the side surfaces of adjacent semiconductor modules 30 face each other with a predetermined interval. Specifically, the side surface 32f of the semiconductor module 30U faces the side surface 32e of the semiconductor module 30V, and the side surface 32f of the semiconductor module 30V faces the side surface 32e of the semiconductor module 30W.

< First cooler >)

The first cooler 40 is configured by a first wall portion of the case 20 in which the semiconductor module 30 is disposed. As shown in fig. 2 to 4, the first cooler 40 includes a bottom wall 21 as a first wall portion, and a flow path 41 formed inside the bottom wall 21 and through which the refrigerant 80 flows. The first cooler 40 cools the semiconductor module 30 from the back surface 32b side. The flow path 41 corresponds to the first flow path.

The flow path 41 is provided so as to overlap at least a part of each of the semiconductor modules 30 in a plan view, so as to effectively cool the semiconductor modules 30. The flow path 41 of the present embodiment is provided so as to enclose most of each of the semiconductor modules 30 in a plan view. The flow path 41 extends along the X direction, which is the arrangement direction of the three semiconductor modules 30. The flow path 41 extends in the X direction.

The refrigerant 80 is supplied to the flow path 41 through the introduction pipe 23. The refrigerant 80 flowing through the flow path 41 is discharged to the outside of the power conversion device 4 via the discharge pipe 24. As the refrigerant 80, a phase-change refrigerant such as water or ammonia, or a non-phase-change refrigerant such as glycols can be used.

< Second cooler >)

The second cooler 50 is provided without taking the housing 20. The second cooler 50 is disposed in the accommodation space 20S of the housing 20. The second cooler 50 is disposed on one surface 32a of the semiconductor module 30 in the accommodation space 20S. An electrical insulating member such as a ceramic plate is disposed between the second cooler 50 and the semiconductor module 30 as necessary. The second cooler 50 cools the semiconductor module 30 from the opposite side to the first cooler 40 in the Z-direction. The second cooler 50 has a flow path 51 in which the refrigerant 80 flows. The refrigerant 80 is supplied to the flow path 51 through the introduction pipe 23. The refrigerant 80 flowing through the flow path 51 is discharged to the outside of the power conversion device 4 via the discharge pipe 24. The flow path 51 corresponds to the second flow path.

The second cooler 50 is thinner than the first cooler 40, i.e., the bottom wall 21, in the Z direction. The second cooler 50 is formed, for example, as a tubular body of a flat shape as a whole. The second cooler 50 is configured to have a flow path therein, for example, using a pair of plates (metal thin plates). At least one of the pair of plates is formed into a shape bulging in the Z direction by press working. Thereafter, the outer peripheral edge portions of the pair of plates are fixed to each other by caulking or the like, and joined to each other over the entire circumference by brazing or the like. Thereby, a flow path 51 through which the refrigerant 80 can flow is formed between the pair of plates. The rigidity of the second cooler 50 thus constructed is lower than that of the first cooler 40.

The flow path 51 is provided so as to overlap at least a part of each of the semiconductor modules 30 in a plan view, so as to effectively cool the semiconductor modules 30. The flow path 51 of the present embodiment is provided so as to overlap most of each of the semiconductor modules 30 in a plan view. The flow path 51 extends along the X direction, which is the arrangement direction of the three semiconductor modules 30. The flow path 51 extends in the X direction. The flow path 51 traverses the three semiconductor modules 30 in the X direction. The flow path 51 is enclosed in the flow path 41 in a plan view. The extension length of the flow path 51 is shorter than the extension length of the flow path 41.

The second cooler 50 is stacked on the first cooler 40 with the semiconductor modules 30 interposed therebetween. The second cooler 50 may be pressed in the Z direction from the surface opposite to the semiconductor module 30 by a pressing member, not shown. By pressing, the second cooler 50 and the semiconductor module 30, and the semiconductor module 30 and the first cooler 40 are held with good heat conduction, respectively. The pressing member includes, for example, a pressing plate and an elastic member. The elastic member is, for example, a member that generates a pressing force by elastic deformation of rubber or the like, or a metal spring. The elastic member is disposed between the pressing plate and the second cooler 50 in the Z direction. By fixing the pressing plate at a predetermined position with respect to the housing 20, the elastic member is elastically deformed. The second cooler 50 and the semiconductor module 30 are pressed against the first cooler 40 (bottom wall 21) due to the reaction force of the elastic deformation.

< Connecting tube >)

The connection pipe 60 connects the first cooler 40 and the second cooler 50. The connecting pipe 60 includes a connecting pipe 61 for supplying the refrigerant 80 to the flow path to which the introduction pipe 23 is not connected, and a connecting pipe 62 for discharging the refrigerant 80 from the flow path to which the discharge pipe 24 is not connected. The connecting pipe 60 has connecting channels 63 communicating with the channels 41 and 51, respectively. The connecting channel 63 extends in the Z direction. One end of the connecting channel 63 communicates with the channel 41, and the other end communicates with the channel 51. The connecting pipe 60 corresponds to a connecting portion.

The connection pipe 61 (connection flow path 63) is connected to the vicinity of one end in the X direction in the second cooler 50 (flow path 51). The connection pipe 62 (connection flow path 63) is connected to the vicinity of the other end of the second cooler 50 (flow path 51). Reference numeral 45 in fig. 4 denotes a seal portion provided around the connecting pipe 60 of the first cooler 40. The sealing portion 45 is provided by, for example, a grommet or the like.

In the present embodiment, the introduction pipe 23 is connected to the flow path 41 near one end in the X direction, and the discharge pipe 24 is connected to the other end. In the X direction, the connection pipe 60 is disposed between a connection position of the introduction pipe 23 and the first cooler 40 and a connection position of the discharge pipe 24 and the first cooler 40.

A part of the refrigerant 80 supplied from the introduction pipe 23 flows through the flow path 41 and is discharged from the discharge pipe 24. The other part of the refrigerant 80 passes through the flow path 41 and the connection flow path 63 of the connection pipe 61, and is supplied to the flow path 51. The refrigerant 80 flowing through the flow path 51 passes through the connecting flow path 63 of the connecting pipe 62, flows into the flow path 41, and is discharged from the discharge pipe 24.

The flow rate of the refrigerant 80 flowing through the flow path 41 is greater than the flow rate of the refrigerant 80 flowing through the flow path 51. The flow path 41 is a main flow path, and the flow path 51 is a sub-flow path branched from the flow path 41. The flow rate of the flow path 41 passing through the branching portion of the connecting pipe 61 is larger than the flow rate of the refrigerant 80 flowing through the flow path 51. The cross-sectional area of the flow path 41 is larger than the cross-sectional area of the flow path 51. The thickness (height) of the first cooler 40 is thicker than the thickness of the second cooler 50 in the Z direction.

The flow path 51 as the sub flow path is branched from the flow path 41 as the main flow path via the connection flow path 63. The cross-sectional area of the connecting channel 63 is smaller than the cross-sectional area of the channel 41. The cross-sectional area of each flow path is an area of a cross-section orthogonal to the extending direction of the flow path, that is, the flow direction of the refrigerant. The water passage resistance of the connecting channel 63 is smaller than the water passage resistance of the channel 51.

Summary of the first embodiment

As described above, in the power conversion device 4 of the present embodiment, the semiconductor module 30 can be cooled from both sides in the Z direction by the first cooler 40 and the second cooler 50.

In a structure including a two-stage cooler, in order to miniaturize the constitution in the Z direction, that is, to reduce the height, it is considered to thin the cooler in the Z direction. However, the flow path becomes narrow, and the pressure loss increases. In the present embodiment, in the configuration including the two-stage cooler, the flow rate of the refrigerant 80 is made different between the flow paths 41 and 51, and the cross-sectional area of the flow path 41 having a larger flow rate is made larger than the cross-sectional area of the flow path 51 having a smaller flow rate. That is, the flow path 51 having a small flow rate is narrowed, and the flow path 41 having a large flow rate is widened. The first cooler 40 having a wide flow path 41 is formed by a part of the case 20 accommodating the semiconductor module 30. The second cooler 50 having a narrow flow path 51 is housed in the case 20 together with the semiconductor module 30. As a result, the height of the power conversion device 4 can be reduced while suppressing an increase in pressure loss.

The size of the cross-sectional area of the connecting channel 63 is not particularly limited. In the present embodiment, the connecting channel 63 is configured to connect the channel 41 as the main channel and the channel 51 as the sub-channel, and therefore, the cross-sectional area of the connecting channel 63 can be reduced as compared with a configuration in which the channel 51 is the main channel. For example, the cross-sectional area of the connecting channel 63 is made smaller than the cross-sectional area of the channel 41. As a result, the power conversion device 4 can be miniaturized in the X direction orthogonal to the Z direction. In particular, in the present embodiment, the water passage resistance of the connecting channel 63 is smaller than the water passage resistance of the channel 51. Therefore, even if the connecting passage 63 is narrowed in the X direction, the refrigerant 80 can be stably supplied from the passage 41 as the main passage to the passage 51 as the sub-passage.

The rigidity of the second cooler 50 may be higher than the rigidity of the first cooler 40, or may be substantially equal to the rigidity of the first cooler 40. In the present embodiment, the rigidity of the second cooler 50 is lower than that of the first cooler 40. As a result, as shown in fig. 5, even if a height deviation of the semiconductor module 30 or an assembly deviation in the Z direction occurs, the deformation of the second cooler 50 can be absorbed. Even if a height deviation or the like occurs, the second cooler 50 is in close contact with the plurality of semiconductor modules 30, and therefore can cool from both sides. Fig. 5 is a sectional view showing the effect of the second cooler 50. Fig. 5 corresponds to fig. 4.

< Modification >

The arrangement order of the three semiconductor modules 30U, 30V, 30W is not limited to the above example. The semiconductor module 30U or the semiconductor module 30W may be disposed in the middle.

An example in which the introduction pipe 23 and the discharge pipe 24 are connected to the first cooler 40 is shown, but the present invention is not limited thereto. The introduction pipe 23 and the discharge pipe 24 may be connected to the second cooler 50. In this case, as shown in fig. 6, the refrigerant 80 is supplied to the flow path 51 of the second cooler 50. A part of the refrigerant 80 flows from the flow path 51 to the flow path 41 of the first cooler 40 via the connecting pipe 61. The refrigerant 80 flowing through the flow path 41 returns to the flow path 51 via the connecting pipe 62 and is discharged. In such a configuration, the cross-sectional area of the flow path 41 having a large flow rate is made larger than the cross-sectional area of the flow path 51 having a small flow rate. The first cooler 40 is formed by a part of the housing 20. This can reduce the height of the power conversion device 4 while suppressing an increase in pressure loss. Fig. 6 is a diagram showing a modification. Fig. 6 corresponds to fig. 4.

(Second embodiment)

The present embodiment is a modification of the previous embodiment, and the description of the previous embodiment can be cited.

Fig. 7 is a cross-sectional view showing the power conversion device 4 of the present embodiment. Fig. 7 corresponds to fig. 4. Fig. 8 is a plan view showing the heat radiating member. The blank arrows of fig. 7 and 8 indicate the flow direction of the refrigerant. In this embodiment, a fin is added to the cooler, compared to the structure described in the previous embodiment. The first cooler 40 includes fins 42 arranged in the flow path 41. The second cooler 50 includes fins 52 arranged in the flow path 51. The fins 42 correspond to the first fins and the fins 52 correspond to the second fins.

As shown in fig. 7, a plurality of fins 42 protrude from a base 43. The heat dissipation member 44 has a base 43 and a plurality of fins 42. The heat dissipation member 44 is disposed so as to overlap the semiconductor module 30 in a plan view. The base 43 is disposed so as to close the opening 211 of the bottom wall 21 communicating with the accommodation space 20S and the flow path 41. The peripheral edge portion of the base 43 is joined liquid-tightly to the opening edge portion of the bottom wall 21 by friction stir welding or the like. This can prevent the refrigerant 80 from leaking outside the flow path 41 through the opening 211. The base 43 forms a flow path 41 together with the bottom wall 21. The seal 46, which is the joint portion of the base 43 and the bottom wall 21, is sealed in a liquid-tight manner. The seal portion 46 is located inside the seal portion 45 in the extending direction of the first cooler 40.

The fins 42 pass through the openings 211 and are disposed in the flow path 41. A plurality of fins 42 protrude from one face of the base 43. The fins 42 extend in the Z direction. The fins 42 are pin-type fins, for example. The fins 42 have a substantially circular shape, a substantially elliptical shape, or the like in plan view. The fin 42 has a predetermined height Fh1 in the Z direction. As shown in fig. 8, the plurality of fins 42 are provided at a predetermined pitch Fp1 in the Y direction. The diameter of each fin 42 is Fd1.

The fins 52 are disposed in the flow path 51 formed by a pair of plates (thin metal plates). The fins 52 are arranged so as to overlap the semiconductor module 30 in a plan view. The fins 52 are, for example, wave-shaped (wave-shaped) fins. The fin 52 has a predetermined height Fh2 in the Z direction. The height Fh2 of the fin 52 is lower than the height Fh1 of the fin 42. Although not shown, the plurality of fins 52 are provided at a predetermined pitch Fp2 in the Y direction. The pitch Fp2 of the fins 52 is smaller than the pitch Fp1 of the fins 42.

The cross-sectional area of the connecting channel 63 of the present embodiment is smaller than the cross-sectional area of the connecting channel 63 shown in the previous embodiment. Thus, the length of the connecting channel 63 in the X direction is shorter than that of the previous embodiment. Even if the cross-sectional area is further reduced, the water passage resistance of the connecting channel 63 is smaller than the water passage resistance of the channel 51. Other configurations of the power conversion device 4 are the same as those described in the previous embodiment.

Summary of the second embodiment

According to the power conversion device 4 of the present embodiment, the same effects as those of the configuration described in the previous embodiment can be obtained. For example, in a structure including a two-stage cooler, the flow rate of the refrigerant 80 is made different between the flow paths 41 and 51, and the cross-sectional area of the flow path 41 having a larger flow rate is made larger than the cross-sectional area of the flow path 51 having a smaller flow rate. The first cooler 40 having a wide flow path 41 is formed by a part of the case 20 accommodating the semiconductor module 30. Therefore, the height of the power conversion device 4 can be reduced while suppressing an increase in pressure loss.

Further, in the present embodiment, the first cooler 40 includes the fins 42, and the second cooler 50 includes the fins 52. Thereby, in the structure including the two-stage cooler, the semiconductor module 30 can be cooled more effectively.

The relationship between the height of the fins 42, 52, the fin pitch, and the like is not particularly limited. In the present embodiment, the height Fh1 of the fin 42 of the flow path 41 having a large flow rate is set to be higher than the height Fh2 of the fin 52 of the flow path 51 having a small flow rate. This can improve the heat transfer coefficients in the flow paths 41 and 51, respectively. Further, the pitch Fp2 of the fins 52 is smaller than the pitch Fp1 of the fins 42. The fin pitch of the flow path 51 having a smaller flow rate is smaller. This can improve the heat transfer coefficient while suppressing an increase in pressure loss.

In the present embodiment, the sealing portion 45 around the connecting pipe 60 is located outside the sealing portion 46 of the heat radiation member 44 in the extending direction of the first cooler 40. Thereby, after the heat radiation member 44 is fixed to the bottom wall 21 of the case 20, the semiconductor module 30 can be disposed on the heat radiation member 44, and the second cooler 50 and the connecting pipe 60 can be assembled. That is, the bottom wall 21 (first wall portion) of the case 20 is utilized as the first cooler 40, and the cooling structure including the fins 42 and 52 can be realized.

As described above, in the present embodiment, the fins 52 are arranged in the flow path 51. The water passage resistance of the flow path 51 is large as compared with a structure not including the fins 52. Therefore, even if the cross-sectional area of the connecting passage 63 is smaller than that of the previous embodiment, the refrigerant 80 can be stably supplied to the passage 51 as the sub-passage. This can further reduce the size of the power conversion device 4 in the X direction.

(Third embodiment)

Fig. 9 is a plan view showing the power conversion device 4 according to the present embodiment. Fig. 9 corresponds to fig. 2. Fig. 10 is a cross-sectional view taken along line X-X of fig. 9. As shown in fig. 9 and 10, the semiconductor module 30 includes power supply terminals 34N, 34P and an output terminal 35. The power terminals 34N and 34P protrude from the side surface 32c of the sealing body 32, and the output terminal 35 protrudes from the side surface 32 d.

In the present embodiment, a capacitor 90 and power supply conductors 91N and 91P are added to the structure described in the first embodiment. That is, the power conversion device 4 further includes a capacitor 90 and power supply conductors 91N, 91P. The configuration other than the capacitor 90 and the power supply conductors 91N and 91P is the same as that described in the first embodiment.

The capacitor 90 provides the smoothing capacitor 6 described above. Capacitor 90 corresponds to a passive component. The capacitor 90 includes, for example, a case not shown and a capacitor element accommodated in the case. In fig. 9 and 10, the capacitor 90 is simplified and illustrated.

The capacitor 90 is disposed on the bottom wall 21 of the housing 20 constituting the first cooler 40. The capacitor 90 of the present embodiment is disposed on the inner surface of the bottom wall 21 in the accommodation space 20S of the case 20. The capacitors 90 are arranged laterally in the Y direction with respect to the semiconductor module 30. The capacitor 90 is substantially rectangular in plan view with the X direction being the longitudinal direction. In the Z direction, the upper end of the capacitor 90 is located farther from the inner surface of the bottom wall 21 than the upper end of the second cooler 50. The upper end of the capacitor 90 is located above, i.e., higher than the upper end of the second cooler 50.

The first cooler 40 cools the semiconductor module 30 and the capacitor 90. The first cooler 40 may have a flow path 41, and the flow path 41 may be provided so as to overlap the capacitor 90 in a plan view in order to cool the capacitor 90. The first cooler 40 of the present embodiment has a flow path 47 different from the flow path 41 in the bottom wall 21. The flow path 47 is provided so as to overlap at least a part of the capacitor 90 in a plan view. The flow path 47 may be provided in parallel with the flow path 41 with respect to the introduction pipe 23 and the discharge pipe 24, or may be connected to the flow path 41 via a connection path not shown.

The power supply conductors 91N and 91P are wiring members for electrically connecting the capacitor 90 to the power supply terminals 34N and 34P of the semiconductor module 30. The power supply conductors 91N and 91P are provided as, for example, plate-shaped metal members. The power supply conductors 91N, 91P are sometimes referred to as power supply bus bars. The power supply conductors 91N and 91P are connected to the corresponding power supply terminals 34N and 34P by solder bonding, resistance welding, laser welding, or the like.

The power supply conductor 91N electrically connects the negative electrode of the capacitor 90 to the power supply terminal 34N of the semiconductor module 30. The power supply conductor 91N is sometimes referred to as a negative electrode conductor, a negative electrode bus bar, an N bus bar, or the like. The power supply conductor 91N constitutes at least a part of the N line 9. The power supply conductor 91P electrically connects the positive electrode of the capacitor 90 to the power supply terminal 34P of the semiconductor module 30. The power supply conductor 91P is sometimes referred to as a positive conductor, a positive bus bar, a P bus bar, or the like. The power supply conductor 91P constitutes at least a part of the P line 8. In fig. 9 and 10, terminal portions of the power supply conductors 91N, 91P for connection to the corresponding power supply terminals 34N, 34P are illustrated.

Summary of the third embodiment

According to the power conversion device 4 of the present embodiment, the same effects as those of the configuration described in the previous embodiment can be obtained.

The power conversion device 4 of the present embodiment includes a capacitor 90. The number of components can be reduced as compared with a configuration in which the capacitor 90 is another component.

In the present embodiment, the capacitor 90 is cooled by the first cooler 40. In order to cool the capacitor 90 that generates heat due to energization, the size of the capacitor 90 can be reduced. This can reduce the height of the power conversion device 4. In addition, since the semiconductor module 30 and the capacitor 90 are cooled by the common cooler (first cooler 40), the number of components can be reduced, and the structure can be simplified.

The positional relationship between the upper end of the second cooler 50 and the upper end of the capacitor 90 is not particularly limited. For example, the upper end of the second cooler 50 may be located above the upper end of the capacitor 90. In the present embodiment, the first cooler 40 is set to a large flow rate and the second cooler 50 is set to a small flow rate, as in the previous embodiment. In addition, as the second cooler 50, a thin structure using a pair of plates (thin metal plates) is adopted. Thus, the upper end of the second cooler 50 is located lower than the upper end of the capacitor 90. Therefore, even with the two-stage cooling structure, the upper end position of the second cooler 50 can be restrained from being limited in height. That is, in the structure including the capacitor 90, the height can be reduced.

In the present embodiment, the power supply terminals 34N, 34P, the output terminal 35, and the power supply conductors 91N, 91P are opposed to the bottom wall 21 constituting the first cooler 40 in the Z direction. The wiring inductance can be reduced by the effect of magnetic flux cancellation due to the eddy current generated in the bottom wall 21.

The structure described in this embodiment can be combined with any of the structures of the first and second embodiments.

< Modification >

An example of the capacitor 90 is shown as a passive component, but is not limited thereto. For example, an inductor constituting the converter may be included as a passive component. Of course, as a passive component, both the capacitor 90 and the inductor may be included.

(Fourth embodiment)

Fig. 11 is an equivalent circuit diagram of the power conversion device 4 of the present embodiment. Fig. 12 is a plan view showing the structure of the power conversion device 4. Fig. 12 corresponds to fig. 2. Fig. 13 is a cross-sectional view taken along line xiii-xiii of fig. 12. Fig. 14 is a cross-sectional view taken along line XIV-XIV of fig. 12. In the present embodiment, the first cooler 40 is configured to include a partition wall of the housing 20.

Circuit structure of power conversion device

As shown in fig. 11, in the present embodiment, the upper and lower arm circuits 10 (10U, 10V, 10W) of each phase are configured to include a plurality of series circuits 12. The plurality of series circuits 12 constituting the upper and lower arm circuits 10 corresponding to one are connected in parallel with each other. As an example, the upper and lower arm circuits 10 of each phase include two series circuits 12. The inverter 5 is configured to include eight series circuits 12. The six arms 10H, 10L are configured to include four MOSFETs 13 connected in parallel to each other, respectively. The four MOSFETs 13 connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage).

< Shell >

As shown in fig. 12 to 14, the housing 20 has a side wall 22 and a partition wall 27. The partition wall 27 corresponds to a first wall and the side wall 22 corresponds to a second wall. The side wall 22 has a cylindrical shape extending in the Z direction. The side wall 22 has a substantially rectangular shape in a plan view in the Z direction, for example. A partition wall 27 is provided inside the side wall 22. A partition wall 27 is connected to the inner surface of the side wall 22 to divide the accommodation space in the side wall 22 into two in the Z direction. The partition wall 27 is, for example, flat. The case 20 has an H shape on the ZY plane, for example. The housing 20 has two accommodation spaces 20S1, 20S2 partitioned by a partition wall 27. The partition wall 27 is arranged to enclose all the semiconductor modules 30 and the capacitors 90 in a plan view in the Z direction. The opening of the accommodation space 20S1 is closed by the cover 25, and the opening of the accommodation space 20S2 is closed by the cover 26.

Semiconductor Module

As shown in fig. 12, the power conversion device 4 has six semiconductor modules 30. Each semiconductor module 30 provides one series circuit 12 as in the previous embodiment. Six semiconductor modules 30 are arranged on one surface of the partition wall 27 as the first wall in the accommodation space 20S 1.

Six semiconductor modules 30 are arranged in two columns every three. The two semiconductor modules 30U constituting the upper and lower arm circuits 10U of the U-phase are arranged continuously in the X-direction so as to constitute the first column 301. The two semiconductor modules 30W constituting the upper and lower arm circuits 10W of the W phase are arranged continuously in the X direction so as to constitute the second column 302. The semiconductor module 30W is arranged to oppose the semiconductor module 30U in the Y direction. The two semiconductor modules 30V constituting the upper and lower arm circuits 10V of the V-phase are arranged in the Y-direction. One of the semiconductor modules 30V constitutes a first column 301, and the other constitutes a second column 302.

In this way, only the semiconductor modules 30V are arranged in the Y direction, and the semiconductor modules 30U and 30W are arranged in the X direction. The three semiconductor modules 30 constituting the first column 301 are arranged in the order of the semiconductor modules 30U, 30V. The three semiconductor modules 30 constituting the second column 302 are arranged in the order of the semiconductor modules 30W, 30V.

The semiconductor modules 30 constituting the first row 301 and the semiconductor modules 30 constituting the second row 302 are arranged so that the side surfaces 32d face each other with a predetermined interval. The semiconductor modules 30 constituting the second column 302 are arranged to be rotated 180 degrees about the Z axis with respect to the semiconductor modules 30 constituting the first column 301. The output terminals 35 of the semiconductor modules 30 constituting the first column 301 protrude from the side surface 32d which is the surface facing the second column 302. The output terminals 35 of the semiconductor modules 30 constituting the second column 302 protrude from the side surface 32d which is the opposite surface opposing the first column 301. The power terminals 34N and 34P protrude from a side surface 32c which is a surface opposite to the side surface 32 d. The other structures are the same as those described in the previous embodiment.

Corresponding output conductors 92U, 92V, 92W are electrically connected to the output terminals 35 of the semiconductor module 30. The output conductors 92U, 92V, 92W are provided as, for example, plate-shaped metal members. The output conductors 92U, 92V, 92W are sometimes referred to as output buses. The output conductors 92U, 92V, 92W are connected to the corresponding output terminals 35 by solder bonding, resistance welding, laser welding, or the like. The output conductors 92U, 92V, 92W face the partition wall 27 of the housing 20 in the Z direction.

The output conductor 92U electrically connects the output terminals 35 of the U-phase semiconductor module 30U. The output conductor 92U extends in the X direction opposite to the arrangement side of the semiconductor module 30V. The output conductor 92V electrically connects the output terminals 35 of the V-phase semiconductor module 30V. The output conductor 92V has a portion extending from a connection portion connected to the output terminal 35 toward the arrangement side of the semiconductor modules 30U, 30W in the X direction. The output conductor 92W electrically connects the output terminals 35 of the W-phase semiconductor module 30W. The output conductor 92W extends in the X direction opposite to the arrangement side of the semiconductor module 30V. That is, the output conductors 92U, 92V, 92W extend in the same direction as each other from the connection portions to which the semiconductor modules 30 are connected.

The power conversion device 4 of the present embodiment includes a current sensor 100. The current sensor 100 detects a phase current. The current sensor 100 is disposed in the accommodation space 20S 1. The current sensor 100 is disposed at the extension ends of the output conductors 92U, 92V, 92W.

< First cooler >)

The first cooler 40 includes a partition wall 27 as a first wall and a flow path provided in the partition wall 27. The flow paths may be shared by the first row 301 and the second row 302, or may be provided separately. The first cooler 40 of the present embodiment includes a flow path 41A and a flow path 41B. The first cooler 40 cools the semiconductor module 30 from the back surface 32b side of the sealing body 32. The structure of the first cooler 40 is the same as that of the previous embodiment except that the first cooler 40 is configured to include the partition wall 27.

The flow paths 41A are provided so as to overlap at least a part of each of the semiconductor modules 30 in the first row 301 in a plan view. The flow paths 41B are provided so as to overlap at least a part of each of the semiconductor modules 30 in the second row 302 in a plan view. Both the flow paths 41A and 41B extend in the X direction. The flow path 41B may be provided in parallel with the flow path 41A with respect to the introduction pipe 23 and the discharge pipe 24, or may be connected to the flow path 41A via a connection path not shown. For example, fins 42 are disposed in the flow paths 41A and 41B, respectively. The heat radiation member 44 may be provided separately from the flow paths 41A and 41B, or the base 43 may be shared by both the flow paths 41A and 41B.

Second cooler and connecting tube

As shown in fig. 12 and 13, the power conversion device 4 includes two second coolers 50A, 50B. The second coolers 50A, 50B cool the corresponding semiconductor modules 30 from the side of one face 32a of the sealing body 32. The second cooler 50A cools the three semiconductor modules 30 of the first column 301. The flow path 51 of the second cooler 50A extends in the X direction and is provided so as to overlap at least a part of each semiconductor module 30 of the second row 302 in a plan view. The second cooler 50B cools the three semiconductor modules 30 of the second column 302. The flow path 51 of the second cooler 50B extends in the X direction and is provided so as to overlap at least a part of each of the three semiconductor modules 30 of the second row 302.

The connecting pipe 60 is provided separately for the second coolers 50A, 50B. The power conversion device 4 includes connection pipes 61A, 62A corresponding to the second cooler 50A and connection pipes 61B, 62B corresponding to the second cooler 50B. The connecting pipes 61A and 62A include connecting passages 63 that communicate with the passage 41A of the first cooler 40 and the passage 51 of the second cooler 50A, respectively. The connecting pipes 61B and 62B include connecting passages 63 that communicate with the passage 41B of the first cooler 40 and the passage 51 of the second cooler 50B, respectively.

< Circuit Board >)

The circuit board 70 is disposed in the accommodation space 20S1 of the semiconductor module 30, as in the previous embodiment. The circuit board 70 is disposed above the six semiconductor modules 30. The signal terminals 33 of six semiconductor modules are mounted on the circuit board 70.

< Capacitor >

The capacitor 90 is disposed in the accommodation space 20S 2. The capacitor 90 is disposed on the surface of the partition wall 27 opposite to the surface on which the semiconductor module 30 is disposed. The capacitor 90 is arranged so as to overlap the semiconductor modules 30 of the first row 301 and the semiconductor modules 30 of the second row 302 in a plan view, for example. The capacitor 90 is arranged so as to overlap the flow paths 41A and 41B in a plan view.

The power supply conductor 91N connected to the negative electrode of the capacitor 90 is inserted into the through hole 212 provided in the partition wall 27, and is connected to the power supply terminal 34N of the semiconductor module 30. The power supply conductor 91P connected to the positive electrode of the capacitor 90 is inserted through the through hole 212 and connected to the power supply terminal 34P of the semiconductor module 30.

Summary of the fourth embodiment

The power conversion device 4 according to the present embodiment is a combination of the structures described in the first, second, and third embodiments. Therefore, the effects described in the previous embodiments can be achieved.

For example, the flow rate of the refrigerant 80 is made different between the flow path 41A of the first cooler 40 and the flow path 51 of the second cooler 50A corresponding to the first row 301 of the semiconductor module 30, and the flow path 41A having a larger flow rate has a larger cross-sectional area than the flow path 51 having a smaller flow rate. Similarly, the flow rate of the refrigerant 80 is made different between the flow paths 41B of the first cooler 40 and the flow paths 51 of the second cooler 50B corresponding to the second row 302 of the semiconductor module 30, and the flow path 41B having a larger flow rate has a larger cross-sectional area than the flow path 51 having a smaller flow rate. The first cooler 40 having the wider flow paths 41A and 41B is formed by a part of the case 20 accommodating the semiconductor module 30. The second coolers 50A and 50B having the narrow flow paths 51 are housed in the case 20 together with the semiconductor module 30. As a result, the height of the power conversion device 4 can be reduced while suppressing an increase in pressure loss.

In the present embodiment, six semiconductor modules 30 are arranged in two rows for every three semiconductor modules. Further, two semiconductor modules 30U (first modules) constituting the upper and lower arm circuits 10U of the U-phase are arranged in the first column 301. Two semiconductor modules 30W (second modules) constituting the upper and lower arm circuits 10W of the W phase are arranged in the second column 302. One of the two semiconductor modules 30V (third modules) constituting the V-phase upper and lower arm circuits 10V is arranged in the first column 301, and the other is arranged in the second column 302. That is, only the semiconductor modules 30V are arranged in the Y direction, and the semiconductor modules 30U and 30W are arranged in the X direction.

As a result, the connection structure between the semiconductor module 30 and the output conductors 92U, 92V, 92W is substantially コ -shaped (substantially U-shaped) in a state in which the output terminals 35 of the common phase are electrically connected by the output conductors 92U, 92V, 92W. In the X direction, one end of the connection structure is closed by a part of the semiconductor module 30V and the output conductor 92V, and the other end is an open end. Therefore, the output conductors 92U, 92V, 92W can be led out to the open end side in the X direction. The output conductors 92U, 92V, 92W can be led out in the same direction in the XY plane. This can reduce the size, that is, the height of the power conversion device 4 in the Z direction.

The positional relationship of the output conductors 92U, 92V, 92W is not particularly limited. In the present embodiment, the X-direction extending portion of the output conductor 92V (third conductor) is arranged between the output conductor 92U (first conductor) and the output conductor 92W (second conductor) in the Y-direction. The output conductors 92U can be arranged in the vicinity of the semiconductor modules 30U arranged in the X direction in the first column 301, and the output conductors 92W can be arranged in the vicinity of the semiconductor modules 30W arranged in the X direction in the second column 302. This allows the extended portion of the output conductor 92V to be led out through the gap between the output conductors 92U and 92W. Therefore, the height of the power conversion device 4 can be further reduced.

The configuration described in this embodiment can be combined with at least one of the configurations described in the first, second, and third embodiments.

< Modification >

The configuration of the six semiconductor modules 30 is not limited to the above-described example. The position of the semiconductor module 30 may also be changed. For example, instead of the semiconductor modules 30V, the semiconductor modules 30U may be arranged in the Y direction. Instead of the semiconductor modules 30V, the semiconductor modules 30W may be arranged in the Y direction.

The number of the series circuits 12 constituting the upper and lower arm circuits 10 corresponding to one, that is, the number of the semiconductor modules 30 of each phase is not limited to two. An even number of four or more may be used. For example, in the case of four, the first column 301 includes four semiconductor modules 30U arranged in succession and two semiconductor modules 30V arranged in succession. The second column 302 includes four semiconductor modules 30W arranged in succession and two semiconductor modules 30V arranged in succession.

(Fifth embodiment)

Fig. 15 is a cross-sectional view showing the power conversion device 4 of the present embodiment. Fig. 15 corresponds to fig. 7. The blank arrows in fig. 15 indicate the flow direction of the refrigerant.

In the power conversion device 4 of the present embodiment, as shown in fig. 15, the second cooler 50 including the flow path 51 having a small flow rate has a high heat transfer region 531 and a low heat transfer region 532. In the second cooler 50, the high heat transfer region 531 is a region of relatively high heat transfer coefficient, and the low heat transfer region 532 is a region of relatively low heat transfer coefficient. The high heat transfer region 531 is a region having a higher heat transfer coefficient than the low heat transfer region 532. The low heat transfer region 532 is a region having a lower heat transfer coefficient than the high heat transfer region 531.

The high heat transfer region 531 is provided so as to overlap at least a part of the semiconductor module 30 in a plan view. In the structure including the plurality of semiconductor modules 30, the high heat transfer region 531 is provided so as to overlap at least a portion of each of the semiconductor modules 30. The high heat transfer region 531 of the present embodiment is provided so as to entirely enclose each semiconductor module 30 in a plan view.

In the arrangement direction of the semiconductor modules 30 as the heating elements, a low heat transfer region 532, a high heat transfer region 531, and a low heat transfer region 532 are provided in this order. The low heat transfer regions 532 are provided between adjacent semiconductor modules 30 in a plan view. A low heat transfer region 532 is provided on the upstream side of the plurality of semiconductor modules 30, and a low heat transfer region 532 is also provided on the downstream side.

As an example, in the present embodiment, the heat transfer coefficients of the high heat transfer region 531 and the low heat transfer region 532 are made different by the fins. The heat transfer coefficient can be adjusted by the presence or absence of fins, the height of the fins, the pitch of the fins, and the like. The second cooler 50 includes fins 52 disposed in the flow path 51, similarly to the configuration described in the previous embodiment (fig. 7). The first cooler 40 may or may not include fins 42. As an example, the first cooler 40 of the present embodiment does not include the fins 42.

As in the previous embodiment, the fins 52 are disposed in the flow paths 51 formed of a pair of plates (thin metal plates). The fin 52 has a first fin portion 521 and a second fin portion 522. The first fin portion 521 is a wave-shaped fin (wave-shaped fin). The first fin portion 521 has a predetermined height in the Z direction. The first fin portions 521 are provided at a predetermined pitch in the Y direction. The second fin portion 522 is a substantially flat plate-shaped fin (straight fin).

The first fin portion 521 and the second fin portion 522 may be separate or integrally connected. The second fin portion 522 may be connected to the first fin portion 521 by being integrally provided continuously, or may be connected by being joined. As an example, the first fin 521 and the second fin 522 of the present embodiment are integrally connected.

The high heat transfer region 531 is a region where the first fin portion 521 is provided in a plan view. The low heat transfer region 532 is a region where the second fin portion 522 is provided in a plan view. In the present embodiment, the difference in heat transfer coefficients is set for the high heat transfer region 531 and the low heat transfer region 532 by making the first fin portion 521 and the second fin portion 522 different in form.

The second cooler 50 may have a region where the fins 52 are not arranged in a plan view. The region in the second cooler 50 where the fins 52 are not provided is a region having a lower heat transfer coefficient than the low heat transfer region 532. Other configurations of the power conversion device 4 are the same as those described in the previous embodiment.

Summary of the fifth embodiment

In addition, in the present embodiment, the second cooler 50 having a smaller flow rate has a high heat transfer region 531 and a low heat transfer region 532. The high heat transfer region 531 is provided so as to overlap at least a part of the semiconductor module 30 that is a heat generating body. Thereby, the semiconductor module 30 can be cooled effectively.

In addition, having the low heat transfer region 532 can reduce the water passage resistance of the flow path 51 as a whole and increase the flow rate of the flow path 51 as compared with the structure of the high heat transfer region 531. Since the flow rate of the second cooler 50 is small, the rate of change of the flow rate is large even if the flow rate is slightly increased. That is, the sensitivity to flow is high. Thereby, the semiconductor module 30 can be cooled effectively.

In particular, in the present embodiment, in a structure including three semiconductor modules 30 (30U, 30V, 30W) constituting the inverter 5, a plurality of regions, which are regions between adjacent semiconductor modules 30, are defined as the low heat transfer region 532. Thereby, the flow rate of the flow path 51 can be further increased, and the semiconductor module 30 can be cooled effectively. Such an effect can be achieved in a structure in which three or more semiconductor modules 30 are arranged.

In the present embodiment, the fins 52 make the heat transfer coefficients of the high heat transfer region 531 and the low heat transfer region 532 different. This can improve the cooling performance while suppressing an increase in pressure loss.

In the present embodiment, the first fin portion 521 provided in the high heat transfer region 531 and the second fin portion 522 provided in the low heat transfer region 532 are integrally connected. The fin 52 is provided as one member including the first fin portion 521 and the second fin portion 522. This can reduce the number of components and thus reduce the cost. In addition, positioning and the like in the flow path 51 can be easily performed, and the manufacturing process can be simplified.

The configuration described in this embodiment can be combined with at least one of the configurations described in the first, second, third, and fourth embodiments. For example, in combination with the second embodiment, the height of the first fin portion 521 of the high heat transfer region 531 may be set lower than the height of the fins 42 arranged in the flow path 41. The pitch of the first fin portions 521 may be smaller than the pitch of the fins 42.

< Modification >

An example in which the heat transfer coefficients of the high heat transfer region 531 and the low heat transfer region 532 are made different by making the fin form different is shown, but is not limited thereto. As described above, the heat transfer coefficients of the high heat transfer region 531 and the low heat transfer region 532 can be made different depending on the presence or absence of fins, the height of fins, the pitch of fins, and the like.

For example, in the example shown in fig. 16, the fins 52 are arranged in a dispersed manner, the region where the fins 52 are provided is referred to as a high heat transfer region 531, and the region where the fins 52 are not provided is referred to as a low heat transfer region 532. The fin 52 is a corrugated fin, as in the first fin portion 521. The fin 52 is provided so as to overlap at least a part of the semiconductor module 30 in a plan view. The low heat transfer region 532 is disposed at a position not overlapping with the semiconductor module 30. In fig. 16, the high heat transfer region 531 is provided so as to entirely enclose each of the semiconductor modules 30 in a plan view. The low heat transfer region 532 is provided between adjacent semiconductor modules 30 in a plan view at a position upstream of the semiconductor modules 30 and downstream of the semiconductor modules 30.

An example in which the heat transfer coefficients of the high heat transfer region 531 and the low heat transfer region 532 are made different by fins is shown, but is not limited thereto.

The first cooler 40 having a wide flow path 41 is constituted by a part of the case 20 accommodating the semiconductor module 30, but is not limited to this. In the present embodiment, the first cooler 40 may be provided without using the housing 20. In this case, the cooling performance can be improved while suppressing an increase in pressure loss.

(Other embodiments)

The disclosure of the present specification, drawings, and the like is not limited to the illustrated embodiments. The present disclosure includes the illustrated embodiments and modifications based on them by a person skilled in the art. For example, the present disclosure is not limited to the combinations of parts and/or elements shown in the embodiments. The present disclosure can be implemented in various combinations. The present disclosure may have an additional portion that can be added to the embodiment. The present disclosure includes embodiments in which components and/or elements of the embodiments are omitted. The present disclosure includes alternatives or combinations of parts and/or elements from one embodiment to another. The technical scope of the present disclosure is not limited to the description of the embodiments. Several technical scope of the present disclosure should be understood to be indicated by the description of the claims, and also include all modifications that are equivalent to the meaning and scope of the description of the claims.

The disclosure in the specification, drawings, etc. is not limited by the description of the claims. The disclosure in the specification, drawings, and the like includes technical ideas described in the claims, and relates to technical ideas that are more diverse and broader than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure of the specification, drawings, and the like without being limited by the descriptions of the claims.

In the case where a certain element or phase is described as being "on", "connected" or "combined" with respect to other elements or phases, it may be directly on, connected to or combined with the other elements or phases, and further, an interposed element or interposed phase may be present. In contrast, when an element is recited as being "directly on," "directly connected to," or "directly coupled to" another element or other phase, there are no intervening elements or intervening phases present. Other words used to describe the relationship between elements should be interpreted in the same manner (e.g., "between" and "directly between", "adjacent" and "directly adjacent", etc.). As used in this specification, the term "and/or" includes any and all combinations related to the associated listed item or items.

Spatially relative terms such as "inner," "outer," "back," "lower," "upper," "higher," and the like are used herein to facilitate description of a 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 in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "lower" or "directly lower" than other elements or features would then be oriented "upper" than the other elements or features. Thus, the term "lower" can include both directions up and down. The device may be oriented in other directions (90 degrees or may be rotated in other directions), and the spatially relative terms used in the present specification are construed accordingly.

The drive system 1 of the vehicle is not limited to the above-described structure. For example, an example including one motor generator 3 is shown, but is not limited thereto. A plurality of motor generators may be included.

In addition, although the example in which the power conversion device 4 includes the inverter 5 as the power conversion circuit is shown, it is not limited thereto. For example, the inverter may be configured to include a plurality of inverters. It may also be configured to include at least one inverter and a converter. Only the converter may be included.

The number of semiconductor modules 30 is not limited to the above example. For example, one semiconductor module 30 may provide one arm 10H, 10L, or one semiconductor module 30 may provide six arms 10H, 10L.

In addition to the semiconductor module 30 or instead of the semiconductor module 30, the above-described two-stage cooling structure, that is, the double-sided cooling structure realized by the first cooler 40 and the second cooler 50 may be applied to a heating element that is another element constituting the power conversion device 4. Other elements are, for example, capacitors, inductors, bus bars.

(Disclosure of technical idea)

The present specification discloses a plurality of technical ideas described in a plurality of items listed below. Some items are sometimes described by multiple dependent forms (a mu L T I P L E DEPENDENT form) that selectively reference the previous item in the subsequent item. In addition, some items are sometimes described by multiple dependent forms (a mu L T I P LEDEPENDENT form REFERR I NG to anothermu L T I P LEDEPENDENT form) that reference items of other multiple dependent forms. These items described in a plurality of subordinate forms define a plurality of technical ideas.

< Technical idea 1 >

A power conversion apparatus comprising:

a semiconductor module (30) that constitutes a power conversion circuit (5);

A case (20) having first wall portions (21, 27) in which the semiconductor modules are arranged, and second wall portions (22) which are connected to the first wall portions and form accommodating spaces (20S, 20S 1) together with the first wall portions, the semiconductor modules being arranged in the accommodating spaces;

a first cooler (40) configured to cool the semiconductor module, the first cooler including the first wall portion and first flow paths (41, 41A, 41B) formed in the first wall portion and through which a refrigerant flows;

A second cooler (50, 50A, 50B) which has a second flow path (51) through which a refrigerant flows, is disposed in the accommodation space on the semiconductor module, and cools the semiconductor module from a side opposite to the first cooler; and

A connection portion (60) having a connection channel (63) communicating with the first channel and the second channel,

The flow rate of the refrigerant flowing through the first flow path is greater than the flow rate of the refrigerant flowing through the second flow path,

The cross-sectional area of the first flow path is larger than the cross-sectional area of the second flow path.

< Technical idea 2 >

The power conversion apparatus according to technical idea 1, wherein,

The second flow path is a sub-flow path branched from the first flow path as a main flow path via the connecting flow path,

The cross-sectional area of the connecting channel is smaller than the cross-sectional area of the first channel.

< Technical idea 3 >

The power conversion device according to claim 2, wherein the water passage resistance of the connecting channel is smaller than the water passage resistance of the second channel.

< Technical idea 4 >

The power conversion apparatus according to any one of technical ideas 1 to 3, wherein,

The first cooler has a first fin (42) disposed in the first flow path, the second cooler has a second fin (52) disposed in the second flow path,

The first fin has a height higher than that of the second fin.

< Technical idea 5 >

The power conversion device according to claim 4, wherein a pitch of the second fins is smaller than a pitch of the first fins.

< Technical idea 6 >

The power conversion apparatus according to technical idea 4 or technical idea 5, wherein,

The first fin protrudes from the base (43), and in the first cooler, a seal portion (45) of the connecting portion is located further outward in the extending direction than a seal portion (46) of the base.

< Technical idea 7 >

The second cooler has a high heat transfer region (531) and a low heat transfer region (532) having a lower heat transfer coefficient than the high heat transfer region,

The high heat transfer region is provided so as to overlap at least a part of the semiconductor module when viewed in a plan view in a lamination direction of the first cooler, the semiconductor module, and the second cooler.

< Technical idea 8 >

The power conversion apparatus according to technical idea 7, wherein,

The second cooler has fins (52) arranged in the second flow path,

The fin includes a first fin portion (521) disposed in the high heat transfer region and a second fin portion (522) disposed in the low heat transfer region and integrally and continuously provided with respect to the first fin portion.

< Technical idea 9 >

The power conversion apparatus according to any one of technical ideas 1 to 8, wherein,

Comprises a plurality of semiconductor modules arranged in a lateral arrangement between the first cooler and the second cooler,

The second cooler has a lower rigidity than the first cooler.

< Technical idea 10 >

The power conversion apparatus according to any one of technical ideas 1 to 9, wherein,

Comprises a passive component (90) which is electrically connected with the semiconductor module in the accommodating space and generates heat by energizing,

The passive component is disposed on the first wall portion and is cooled by the first cooler.

< Technical idea 11 >

The power conversion device according to claim 10, wherein an upper end of the second cooler is located lower than an upper end of the passive component in a lamination direction of the first cooler, the semiconductor module, and the second cooler.

Claims

1. A power conversion apparatus comprising:

A semiconductor module (30) that constitutes a power conversion circuit (5);

A case (20) having first wall portions (21, 27) in which the semiconductor modules are arranged and second wall portions (22) that are connected to the first wall portions and that form accommodating spaces (20S, 20S 1) together with the first wall portions, the semiconductor modules being arranged in the accommodating spaces;

A first cooler (40) configured to include the first wall portion and a first flow path (41, 41A, 41B) that is formed inside the first wall portion and through which a refrigerant flows, and cool the semiconductor module;

A second cooler (50, 50A, 50B) that has a second flow path (51) through which a refrigerant flows, is disposed on the semiconductor module in the accommodation space, and cools the semiconductor module from a side opposite to the first cooler; and

2. The power conversion device according to claim 1, wherein,

3. The power conversion device according to claim 2, wherein,

The water passage resistance of the connecting channel is smaller than the water passage resistance of the second channel.

4. The power conversion device according to claim 1, wherein,

The first cooler has a first fin (42) disposed in the first flow path,

The second cooler has a second fin (52) disposed in the second flow path,

The first fins have a height greater than a height of the second fins.

5. The power conversion device according to claim 4, wherein,

The second fins have a smaller pitch than the first fins.

6. The power conversion apparatus according to claim 4or 5, wherein,

The first fin protrudes from the base (43),

In the first cooler, a sealing part (45) of the connecting part is positioned at a position which is more outside than a sealing part (46) of the base in the extending direction.

7. The power conversion device according to claim 1, wherein,

The second cooler has a high heat transfer region (531) and a region having a lower heat transfer coefficient than the high heat transfer region, i.e., a low heat transfer region (532),

8. The power conversion device according to claim 7, wherein,

The second cooler has fins (52) arranged in the second flow path,

The fin includes a first fin portion (521) disposed in the high heat transfer region and a second fin portion (522) disposed in the low heat transfer region and connected to the first fin portion.

9. The power conversion device according to claim 1, wherein,

Comprising a plurality of said semiconductor modules in question,

A plurality of the semiconductor modules are arranged in a lateral arrangement between the first cooler and the second cooler,

The second cooler has a lower rigidity than the first cooler.

10. The power conversion device according to claim 1, wherein,

Comprises a passive component (90) which is electrically connected with the semiconductor module in the accommodating space and generates heat by being electrified,

11. The power conversion device according to claim 10, wherein,

An upper end of the second cooler is located lower than an upper end of the passive component in a lamination direction of the first cooler, the semiconductor module, and the second cooler.