JP7180540B2 - power conversion unit - Google Patents

Description

The disclosure described in this specification relates to a power conversion unit in which a plurality of switch modules and capacitors are connected via busbars.

2. Description of the Related Art As disclosed in Patent Literature 1, a power conversion device is known in which a plurality of semiconductor modules are connected to capacitor elements via busbars.

JP 2018-98913 A

The bus bar described in Patent Literature 1 includes an electrode portion connected to a capacitor element and a base portion coupled to the electrode portion. A plurality of holes are formed in the base. Branches extend from the edges of the holes. The tip of the terminal of the semiconductor module passes through this hole. The tip of this terminal is connected to the branch.

By the way, the base of the bus bar is formed with the same number of holes and branches as the total number of terminals provided in the plurality of semiconductor modules. Therefore, when the number of semiconductor modules increases, the shape of the busbar must be changed to increase the number of holes and branches. As described above, the bus bar described in Patent Document 1 has a problem of low versatility for an increase in the number of terminals of a semiconductor module.

Therefore, an object of the disclosure described in this specification is to provide a power conversion unit in which the versatility of the bus bar is improved.

One disclosed is a plurality of switch modules (530 to 536) arranged in an array direction,
busbars (303, 304) exposed from the upper surfaces (543e) of the plurality of switch modules and connected to the plurality of connection terminals (540a, 540b) arranged in the arrangement direction ;
a capacitor (550) connected to each of the plurality of switch modules via a busbar;
The bus bar includes a plurality of connection portions (311h, 315i) arranged in the array direction , the number of which is greater than the total number of connection terminals , a base portion (311, 315) that integrally connects each of the plurality of connection portions, and a base portion that is integrated with the base portion. an electrode portion (312, 316) coupled to and connected to the electrodes of the capacitor ;
The base is provided above the upper surface in a manner facing the upper surface,
The base has a plurality of through holes (311g, 315h) arranged in the array direction, the number of which is greater than the total number of connection terminals,
Each of the connection portions rises upward from the side wall that defines the through hole,
The connection terminals are respectively passed through some of the plurality of through holes,
A plurality of connection terminals are connected to some of the plurality of connection portions.

According to this, even if the total number of connection terminals (540a, 540b) increases as a result of an increase in the number of switch modules (530 to 536), a plurality of of switch modules (530-536) and a capacitor (550) can be connected. In this way, the versatility of the busbars (303, 304) is improved with respect to changes in the number of switch modules (530-536).

It should be noted that the reference numbers in parentheses above merely indicate the correspondence with the configurations described in the embodiments described later, and do not limit the technical scope in any way.

1 is a circuit diagram showing an in-vehicle system; FIG. It is a partial perspective view of a power conversion unit. 4 is a partially exploded perspective view of the power conversion unit; FIG. It is a top view which shows a power module. FIG. 4 is a plan view showing a state in which a P busbar is connected to a power module; FIG. 4 is a plan view showing a state in which a capacitor element is connected to a P bus bar; It is a top view which shows the state in which the insulating substrate was provided in P bus bar. FIG. 4 is a plan view showing a state in which N busbars are connected to the power module and the capacitor element, respectively; It is a top view which shows the modification of the connection form of a power module and a P bus bar. It is a top view which shows the modification of the connection form of a power module and a P bus bar. It is a top view which shows the modification of the connection form of a power module and a P bus bar. It is a top view which shows the modification of the connection form of a power module and a P bus bar.

Embodiments will be described below with reference to the drawings. However, FIGS. 4 to 12 schematically show various constituent elements.

(First embodiment)
<In-vehicle system>
First, an in-vehicle system 100 provided with a power conversion unit 300 will be described based on FIG. This in-vehicle system 100 constitutes a system for an electric vehicle. In-vehicle system 100 has battery 200 , power conversion unit 300 , and motor 400 .

In-vehicle system 100 also includes a plurality of ECUs (not shown). These multiple ECUs transmit and receive signals to and from each other via bus wiring. A plurality of ECUs cooperate to control the electric vehicle. Power running and regeneration of motor 400 according to the SOC of battery 200 are controlled by a plurality of ECUs. SOC is an abbreviation for state of charge. ECU is an abbreviation for electronic control unit.

Battery 200 has a plurality of secondary batteries. These secondary batteries constitute a battery stack connected in series. The SOC of this battery stack corresponds to the SOC of battery 200 . A lithium-ion secondary battery, a nickel-hydrogen secondary battery, an organic radical battery, or the like can be used as the secondary battery.

A power conversion device 500 included in the power conversion unit 300 performs power conversion between the battery 200 and the motor 400 . The power conversion device 500 converts the DC power of the battery 200 into AC power having a voltage level suitable for powering the motor 400 . The power conversion device 500 converts AC power generated by power generation (regeneration) of the motor 400 into DC power at a voltage level suitable for charging the battery 200 .

The motor 400 has a first MG401 and a second MG402. The output shafts of these two MGs are connected to an axle 404 of the electric vehicle via a gearbox 403. Rotational energy of each of the first MG 401 and the second MG 402 is transmitted to the running wheels of the electric vehicle via the gearbox 403 and the axle 404 . Conversely, the rotational energy of the running wheels is transmitted to first MG 401 and second MG 402 via axle 404 and gearbox 403 . MG is an abbreviation for motor generator.

The first MG 401 and the second MG 402 are powered by AC power supplied from the power converter 500 respectively. This imparts a propulsive force to the running wheels. Also, the first MG 401 and the second MG 402 are regenerated by rotational energy transmitted from the running wheels. The AC power generated by this regeneration is converted into DC power and stepped down by the power conversion device 500 . This DC power is supplied to battery 200 . The DC power is also supplied to various electrical loads mounted on the electric vehicle.

<Power converter>
Next, the power conversion device 500 included in the power conversion unit 300 will be described. A power conversion device 500 includes a converter 501 and an inverter 502 . Converter 501 boosts the DC power of battery 200 to a voltage level suitable for powering motor 400 . Inverter 502 converts this DC power to AC power. This AC power is supplied to the motor 400 . Inverter 502 converts AC power generated by motor 400 into DC power. Converter 501 steps down this DC power to a voltage level suitable for charging battery 200 .

As shown in FIG. 1, converter 501 is electrically connected to battery 200 via positive bus bar 301 and negative bus bar 302 . Converter 501 is electrically connected to inverter 502 via P bus bar 303 and N bus bar 304 .

<Converter>
Converter 501 has first capacitor 510 , reactor 520 and A-phase switch module 530 .

As shown in FIG. 1 , one end of positive bus bar 301 is connected to the positive electrode of battery 200 . One end of negative bus bar 302 is connected to the negative electrode of battery 200 . One of the two electrodes of first capacitor 510 is connected to positive bus bar 301 . The other of the two electrodes of first capacitor 510 is connected to negative bus bar 302 .

One end of reactor 520 is connected to the other end of positive bus bar 301 . The other end of reactor 520 is connected to A-phase switch module 530 via an A-phase busbar (not shown). Thus, the positive electrode of battery 200 and A-phase switch module 530 are electrically connected via reactor 520 . In addition, in FIG. 1, the connection part of various busbars is shown by the white circle. These connecting portions are electrically connected by bolts, welding, or the like.

The A-phase switch module 530 has a high side switch 541 and a low side switch 542 . The A-phase switch module 530 also has a high-side diode 541a and a low-side diode 542a. These semiconductor elements are covered and protected by, for example, a sealing resin 543 shown in FIG.

In this embodiment, n-channel IGBTs are used as the high-side switch 541 and the low-side switch 542 . The tips of the terminals connected to the collector electrodes, emitter electrodes, and gate electrodes of the high-side switch 541 and low-side switch 542 are exposed outside the sealing resin 543 of the switch module.

As shown in FIG. 1, the emitter electrode of the high side switch 541 and the collector electrode of the low side switch 542 are connected. Thereby, the high side switch 541 and the low side switch 542 are connected in series.

Also, the collector electrode of the high side switch 541 is connected to the cathode electrode of the high side diode 541a. The emitter electrode of the high side switch 541 is connected to the anode electrode of the high side diode 541a. Thus, the high side diode 541 a is connected in anti-parallel to the high side switch 541 .

Similarly, the collector electrode of the low-side switch 542 is connected to the cathode electrode of the low-side diode 542a. An emitter electrode of the low-side switch 542 is connected to an anode electrode of a low-side diode 542a. Thus, the low side diode 542 a is connected in anti-parallel to the low side switch 542 .

As described above, the high side switch 541 and the low side switch 542 are covered and protected by the sealing resin 543 . The ends of terminals connected to the collector electrode of the high-side switch 541, the midpoint between the high-side switch 541 and the low-side switch 542, and the emitter electrode of the low-side switch 542 are exposed from the sealing resin 543. there is The tips of the terminals connected to the gate electrodes of the high-side switch 541 and the low-side switch 542 are exposed from the sealing resin 543 . These terminals are hereinafter referred to as collector terminal 540a, midpoint terminal 540c, emitter terminal 540b, and gate terminal 540d.

This collector terminal 540 a is connected to the P bus bar 303 . Emitter terminal 540 b is connected to N bus bar 304 . As a result, the high side switch 541 and the low side switch 542 are serially connected in order from the P bus bar 303 toward the N bus bar 304 .

A midpoint terminal 540c is connected to the other end of the reactor 520 via an A-phase bus bar (not shown). One end of the reactor 520 is connected to the positive bus bar 301 as described above. Reactor 520 is connected to the positive electrode of battery 200 and middle point terminal 540c of A-phase switch module 530 by the electrical connection configuration described above.

A gate terminal 540d of each of the high-side switch 541 and the low-side switch 542 is connected to the gate driver. The ECU generates control signals and outputs them to the gate drivers. The gate driver amplifies the control signal and outputs it to gate terminal 540d. Accordingly, the high side switch 541 and the low side switch 542 are controlled to be opened and closed by the ECU. As a result, the voltage level of the DC power input to converter 501 is stepped up or down.

The ECU generates pulse signals as control signals. The ECU adjusts the step-up/step-down level of the DC power by adjusting the on-duty ratio and frequency of this pulse signal. This step-up/down level is determined according to the target torque of motor 400 and the SOC of battery 200 .

When boosting the DC power of battery 200, the ECU alternately opens and closes high-side switch 541 and low-side switch 542, respectively. Conversely, when stepping down the DC power supplied from inverter 502, the ECU fixes the control signal output to low-side switch 542 at a low level. At the same time, the ECU sequentially switches the control signal output to the high-side switch 541 between high level and low level.

<Inverter>
Inverter 502 has second capacitor 550 and U-phase switch module 531 to Z-phase switch module 536 . One of the two electrodes of second capacitor 550 is connected to P bus bar 303 . The other of the two electrodes of second capacitor 550 is connected to N bus bar 304 . U-phase switch module 531 to Z-phase switch module 536 are connected to P bus bar 303 and N bus bar 304, respectively.

Each of U-phase switch module 531 to Z-phase switch module 536 has components equivalent to A-phase switch module 530 . That is, each of the U-phase switch module 531 to Z-phase switch module 536 has a high-side switch 541, a low-side switch 542, a high-side diode 541a, a low-side diode 542a, and a sealing resin 543. Each of these six-phase switch modules also has a collector terminal 540a, an emitter terminal 540b, a midpoint terminal 540c, and a gate terminal 540d.

The X-phase switch module 534 to Z-phase switch module 536 have the same configuration as the U-phase switch module 531 to W-phase switch module 533 . Therefore, FIG. 1 shows the X-phase switch module 534 to Z-phase switch module 536 in a simplified manner.

A collector terminal 540 a of each of these six-phase switch modules is connected to the P bus bar 303 . Emitter terminal 540 b is connected to N bus bar 304 .

A midpoint terminal 540 c of the U-phase switch module 531 is connected to the U-phase stator coil of the first MG 401 via a U-phase bus bar 561 . A midpoint terminal 540 c of the V-phase switch module 532 is connected to the V-phase stator coil of the first MG 401 via a V-phase busbar 562 . A midpoint terminal 540 c of the W-phase switch module 533 is connected to the W-phase stator coil of the first MG 401 via a W-phase bus bar 563 .

Similarly, the midpoint terminal 540 c of the X-phase switch module 534 is connected to the X-phase stator coil of the second MG 402 via the X-phase bus bar 564 . A middle point terminal 540 c of the Y-phase switch module 535 is connected to the Y-phase stator coil of the second MG 402 via a Y-phase bus bar 565 . A midpoint terminal 540 c of the Z-phase switch module 536 is connected to the Z-phase stator coil of the second MG 402 via a Z-phase busbar 566 .

As described above, the inverter 502 has a total of 6-phase switch modules corresponding to the 3-phase stator coils of the first MG 401 and the second MG 402 respectively. The gate terminals 540d of the high-side switches 541 and the low-side switches 542 provided in each of these six-phase switch modules are connected to the gate driver.

When powering each of the first MG 401 and the second MG 402, each of the high-side switch 541 and the low-side switch 542 provided in the six-phase switch module is PWM-controlled by the output of the control signal from the ECU. As a result, inverter 502 generates a three-phase alternating current. When each of the first MG 401 and the second MG 402 generates (regenerates) power, the ECU stops outputting the control signal, for example. AC power generated by power generation thereby passes through diodes provided in the six-phase switch module. As a result, AC power is converted to DC power.

The types of switch elements provided in each of the A-phase switch module 530 and U-phase switch modules 531 to Z-phase switch modules 536 are not particularly limited, and MOSFETs, for example, may be employed. Semiconductor elements such as switches and diodes included in these switch modules can be manufactured from semiconductors such as Si and wide-gap semiconductors such as SiC. The constituent material of the semiconductor element is not particularly limited.

<Configuration of power converter>
Next, the configuration of the power conversion unit 300 will be described. Accordingly, the three directions that are orthogonal to each other are hereinafter referred to as the x-direction, the y-direction, and the z-direction. The x direction corresponds to the array direction.

As shown in FIGS. 2 and 3, power converter unit 300 has cooler 610, capacitor case 630, and insulating plate 640 in addition to power converter 500 described above based on FIG.

Cooler 610 functions to accommodate and cool the seven switch modules described thus far. The capacitor case 630 functions to house the first capacitor 510 and the second capacitor 550 . Concurrently, capacitor case 630 functions to support positive bus bar 301, negative bus bar 302, P bus bar 303, and N bus bar 304, respectively. The insulating plate 640 functions to insulate the P bus bar 303 and the N bus bar 304 from each other and regulate their positions.

2, illustration of the positive bus bar 301 and the negative bus bar 302 is omitted. In FIG. 3, illustration of the positive bus bar 301, the negative bus bar 302, and the first capacitor 510 is omitted.

<Switch module>
The switch module has the sealing resin 543 as described above. This sealing resin 543 has a flat shape with a thin thickness in the x direction. As shown in FIGS. 2 to 4, the sealing resin 543 has a rectangular parallelepiped shape with six faces. The sealing resin 543 has a first main surface 543a and a second main surface 543b spaced apart in the x direction, a left surface 543c and a right surface 543d spaced in the y direction, and a top surface 543e spaced in the z direction. It has a lower surface.

As shown in FIGS. 2 to 4, tips of collector terminal 540a, emitter terminal 540b, and center terminal 540c protrude from upper surface 543e. The collector terminal 540a, the emitter terminal 540b, and the midpoint terminal 540c are arranged in order from the right surface 543d toward the left surface 543c. Further, the tip of the gate terminal 540d protrudes from the lower surface described above. The collector terminal 540a and the emitter terminal 540b correspond to connection terminals.

<Cooler>
As shown in FIG. 4, the cooler 610 has a supply pipe 611 , a discharge pipe 612 and a plurality of relay pipes 613 . The supply pipe 611 and the discharge pipe 612 are connected via a plurality of relay pipes 613 . Refrigerant is supplied to the supply pipe 611 . This refrigerant flows from the supply pipe 611 to the discharge pipe 612 via a plurality of relay pipes 613 .

The supply pipe 611 and the discharge pipe 612 each extend in the x-direction. The supply pipe 611 and the discharge pipe 612 are separated in the y-direction. Each of the multiple relay pipes 613 extends along the y direction from the supply pipe 611 toward the discharge pipe 612 . A supply port 611a of the supply pipe 611 to which the coolant is supplied from the outside and a discharge port 612a of the discharge pipe 612 which discharges the coolant supplied from the relay pipe 613 to the outside are spaced apart in the y direction.

A plurality of relay pipes 613 are spaced apart in the x direction and arranged side by side. A gap is formed between two adjacent relay pipes 613 . Cooler 610 has a total of seven air gaps. An A-phase switch module 530 and U-phase switch modules 531 to Z-phase switch modules 536 are individually provided in each of these seven gaps. This constitutes a power module.

The second main surface 543b of each of the seven-phase switch modules located in the air gap of the cooler 610 is located on the supply port 611a (discharge port 612a) side in the x direction. The right surface 543d is located on the supply pipe 611 side in the y direction. The left surface 543c is located on the discharge pipe 612 side. For this reason, the collector terminal 540a, the emitter terminal 540b, and the midpoint terminal 540c of each of the seven-phase switch modules are arranged in the y-direction from the supply pipe 611 toward the discharge pipe 612 in order.

The main surface of each of these 7-phase switch modules is in contact with the relay pipe 613 . The contact area between the two is increased by an urging force applied from a spring body (not shown). As a result, the heat generated in each of the seven-phase switch modules can be dissipated to the coolant via the relay pipe 613 .

In the present embodiment, the U-phase switch module 531 to W-phase switch module 533, the A-phase switch module 530, and the X-phase switch module 534 to Z-phase switch module 536 are arranged in this order in the direction away from the supply port 611a in the x direction. Lined up. Therefore, the U-phase switch module 531 to W-phase switch module 533 are located upstream of the refrigerant flowing through the supply pipe 611 and the relay pipe 613, respectively, from the X-phase switch module 534 to Z-phase switch module 536 . The U-phase switch module 531 to W-phase switch module 533 are cooled more easily by the refrigerant than the X-phase switch module 534 to Z-phase switch module 536 .

<Capacitor case and capacitor element>
Capacitor case 630 is made of an insulating resin material. The first capacitor 510 and the second capacitor 550 are accommodated in the capacitor case 630 . Although not shown, portions of the positive bus bar 301 and the negative bus bar 302 connected to the first capacitor 510 are exposed from the capacitor case 630 .

As shown in FIG. 3, the second capacitor 550 of this embodiment has a first capacitor element 551 and a second capacitor element 552 . Each of the first capacitor element 551 and the second capacitor element 552 has a prismatic shape extending in the y direction. Each of the first capacitor element 551 and the second capacitor element 552 has two bottom surfaces spaced apart in the y direction. Electrodes are formed on each of these two bottom surfaces.

The first capacitor element 551 and the second capacitor element 552 are housed in the capacitor case 630 so as to line up in the x direction. A P bus bar 303 is connected to one of the two electrodes of these two capacitor elements. An N bus bar 304 is connected to the other of the two electrodes. Two capacitor elements are connected in parallel between the P bus bar 303 and the N bus bar 304 . The total capacitance of these two capacitor elements is the capacitance of the second capacitor 550 .

<P bus bar>
The P bus bar 303 is manufactured by pressing a metal flat plate. As shown in FIG. 3, the P bus bar 303 is formed by integrally connecting a first base portion 311 having a thin thickness in the z direction and a first electrode portion 312 having a thin thickness in the y direction. The P bus bar 303 has a substantially L shape on a plane facing the x direction.

The first base portion 311 has a rectangular shape with the x direction as the longitudinal direction on a plane facing the z direction. The first base 311 has a first upper surface 311a and a first lower surface aligned in the z-direction. Also, the first base portion 311 has four side surfaces connecting these two surfaces. The first base portion 311 has a first left surface 311c and a first right surface 311d aligned in the y direction, and a first front surface 311e and a first rear surface 311f aligned in the x direction.

As shown in FIG. 3, the first base portion 311 is formed with a first through hole 311g penetrating between the first upper surface 311a and the first lower surface. The first through hole 311g is located closer to the first left surface 311c than the first right surface 311d in the y direction. The first right surface 311d side of the first base portion 311 is an area where the first through holes 311g are not formed.

In this embodiment, a total of ten first through holes 311g are formed in the first base portion 311 . These ten first through holes 311g are spaced apart in the x direction. 10 first through holes 311g are arranged in 10 rows and 1 column with the x direction and the y direction as matrix directions.

Also, the first base portion 311 is integrally connected with a first connection portion 311h that rises in the z-direction from the annular side surface that defines the first through hole 311g toward the upper side of the first upper surface 311a. A total of 10 first connection portions 311h are spaced apart in the x direction.

The first electrode portion 312 has a rectangular shape with the x direction as the longitudinal direction on a plane facing the y direction. The first electrode portion 312 has a first electrode surface 312a and a first back surface 312b aligned in the y direction. The first electrode portion 312 has four side surfaces connecting these two surfaces.

The first electrode portion 312 is longer than the first base portion 311 in the x direction. A part of one of the two side surfaces of the first electrode portion 312 extending in the x direction is connected to the first right surface 311 d of the first base portion 311 . A portion of one of the two side surfaces of the first electrode portion 312 extending in the x-direction is disconnected from the first base portion 311 .

In the following description, a portion of the first electrode portion 312 that extends in the x direction and includes a portion that is connected to the first base portion 311 is referred to as a first connection portion 313 for the sake of simplicity. A portion of the first electrode portion 312 that extends in the x direction while including a portion that is not connected to the first base portion 311 is referred to as a first non-connecting portion 314 .

One of the two side surfaces extending in the z direction on a plane facing the y direction of the first connecting portion 313 is integrally connected to the first non-connecting portion 314 . The first non-connecting portion 314 extends in the x-direction away from one of these two side surfaces. The other of these two side surfaces is continuously connected to the first front surface 311e of the first base portion 311 on a plane facing the x direction.

Because of the connection form between the first base portion 311 and the first electrode portion 312 described above, the creepage distance between the first connection portion 311h formed in the first base portion 311 and the first connection portion 313 is longer than the creepage distance. The creepage distance between the first connection portion 311h and the first non-connection portion 314 is longer.

<Insulating plate>
The insulating plate 640 is made of an insulating resin material. As shown in FIG. 3, the insulating plate 640 has a flat plate shape with a thin thickness in the z direction.

The insulating plate 640 has a rectangular shape with its longitudinal direction in the x direction on a plane facing the z direction. The insulating plate 640 has a second top surface 640a and a second bottom surface aligned in the z-direction. Also, the insulating plate 640 has four sides connecting these two sides. The insulating plate 640 has a second left surface 640c and a second right surface 640d aligned in the y direction, and a second front surface 640e and a second rear surface 640f aligned in the x direction.

As shown in FIG. 3, the insulating plate 640 is formed with a second through hole 640g and a third through hole 640h penetrating the second upper surface 640a and the second lower surface. The second through hole 640g is farther from the second left surface 640c in the y direction than the third through hole 640h. In other words, the third through hole 640h is positioned closer to the second left surface 640c in the y direction than the second through hole 640g.

In this embodiment, the insulating plate 640 is formed with a total of ten second through holes 640g and a total of ten third through holes 640h. The ten second through holes 640g are spaced apart in the x direction. The ten third through holes 640h are also spaced apart in the x direction. These ten second through-holes 640g and ten third through-holes 640h are spaced apart in the y direction. A total of 20 through-holes are arranged in 10 rows and 2 columns with the x direction and the y direction as matrix directions.

<N Busbar>
The N bus bar 304 is manufactured by pressing a metal flat plate. As shown in FIG. 3, the N bus bar 304 is formed by integrally connecting a second base portion 315 having a thin thickness in the z direction and a second electrode portion 316 having a thin thickness in the y direction. The N bus bar 304 has a substantially L shape on a plane facing the x direction.

The second base portion 315 has a rectangular shape with the x direction as the longitudinal direction on a plane facing the z direction. The second base 315 has a third upper surface 315a and a third lower surface aligned in the z-direction. The second base portion 315 also has four side surfaces connecting these two surfaces. The second base 315 has a third left surface 315c and a third right surface 315d aligned in the y direction, and a third front surface 315e and a third rear surface 315f aligned in the x direction.

As shown in FIG. 3, the second base portion 315 is formed with a fourth through hole 315g and a fifth through hole 315h penetrating the third upper surface 315a and the third lower surface. The fourth through hole 315g is farther from the third left surface 315c in the y direction than the fifth through hole 315h. In other words, the fifth through hole 315h is positioned closer to the third left surface 315c in the y direction than the fourth through hole 315g.

In this embodiment, a total of 10 fourth through holes 315g and a total of 10 fifth through holes 315h are formed in the second base portion 315. As shown in FIG. The ten fourth through holes 315g are spaced apart in the x direction. The ten fifth through holes 315h are also spaced apart in the x direction. These ten fourth through-holes 315g and ten fifth through-holes 315h are spaced apart in the y direction. A total of 20 through-holes are arranged in 10 rows and 2 columns with the x direction and the y direction as matrix directions.

A second connection portion 315i is integrally connected to the second base portion 315 and rises in the z-direction from the annular side surface defining the fifth through hole 315h toward the upper portion of the third upper surface 315a. A total of ten second connection portions 315i are spaced apart in the x direction.

The second electrode portion 316 has a rectangular shape with the x direction as the longitudinal direction on a plane facing the y direction. The second electrode portion 316 has a second electrode surface 316a and a second back surface 316b aligned in the y direction. The second electrode portion 316 has four side surfaces connecting these two surfaces.

The second electrode portion 316 is longer than the second base portion 315 in the x direction. A part of one of the two side surfaces of the second electrode portion 316 extending in the x direction is connected to the third right surface 315 d of the second base portion 315 . A portion of one of the two side surfaces of the second electrode portion 316 extending in the x direction is disconnected from the second base portion 315 .

In the following description, a portion of the second electrode portion 316 that extends in the x direction and includes a portion that is connected to the second base portion 315 is referred to as a second connection portion 317 for the sake of simplicity. A portion of the second electrode portion 316 that extends in the x-direction while including a portion that is not connected to the second base portion 315 is referred to as a second non-connecting portion 318 .

One of the two side surfaces extending in the z direction on a plane facing the y direction of the second connecting portion 317 is integrally connected to the second non-connecting portion 318 . The second non-connecting portion 318 extends in the x-direction away from one of these two side surfaces. The other of these two side surfaces is continuously connected to the third front surface 315e of the second base 315 on a plane facing the x direction.

Because of the connection form between the second base portion 315 and the second electrode portion 316 described above, the creepage distance between the second connection portion 315i formed in the second base portion 315 and the second connection portion 317 is shorter than the creepage distance. The creepage distance between the second connection portion 315i and the second non-connection portion 318 is longer.

<Connection type>
Next, the form of connection between the first capacitor element 551 and the second capacitor element 552 via the P bus bar 303 and the N bus bar 304 of the switch module will be described with reference to FIGS. 4 to 8. FIG. In these drawings, the collector terminal 540a, the emitter terminal 540b, and the midpoint terminal 540c are shown in black for clarity of notation.

4 to 8 show that the P bus bar 303 and the N bus bar 304 are individually arranged in the switch module for convenience of explanation. However, for example, a busbar module in which these two busbars are integrally connected via an insulating plate 640 may be arranged in the switch module. A busbar module connected to the first capacitor element 551 and the second capacitor element 552 and partly housed in the capacitor case 630 may be arranged in the switch module.

The ten first through holes 311g and the first connecting portions 311h arranged in the x-direction will be given numbers that increase from the first front surface 311e toward the first rear surface 311f. . Similarly, ten second through-holes 640g and ten third through-holes 640h arranged in the x-direction are assigned numbers that increase from the second front surface 640e toward the second rear surface 640f. explain. Ten fourth through-holes 315g, fifth through-holes 315h, and second connecting portions 315i arranged in the x-direction have numbers that increase from the third front surface 315e toward the third rear surface 315f. is given and explained. In FIGS. 5 to 8, numbers 1 to 10 indicating this number are illustrated next to the through holes. The first number is located on the supply port 611a (discharge port 612a) side of the cooler 610 in the x direction.

As shown in FIG. 5, the P bus bar 303 is configured such that the first lower surface of the first base 311 faces the upper surface 543e of each of the seven-phase switch modules and each of the supply pipes 611 of the cooler 610 in the z direction. It is provided above the module. Seven of the ten first through holes 311g formed in the first base 311 are passed through the collector terminals 540a of the seven-phase switch module. In this embodiment, the collector terminals 540a are passed through the first through seventh first through holes 311g.

Specifically, the collector terminals 540a of the U-phase switch module 531 to the W-phase switch module 533 are passed through the first to third first through holes 311g on the end side. The collector terminal 540a of the A-phase switch module 530 is passed through the fourth first through hole 311g on the central side. The collector terminals 540a of the X-phase switch module 534 to Z-phase switch module 536 are passed through the fifth to seventh first through holes 311g on the central side.

The collector terminal 540a passing through the first through hole 311g protrudes above the first upper surface 311a in the z direction. The tip of the collector terminal 540a protruding upward from the first upper surface 311a and the first connecting portion 311h are joined by laser irradiation so as to face each other in the x direction.

As shown in FIG. 6, the first capacitor element 551 and the second capacitor element 552 are attached to the P bus bar 303 so as to face the non-formed region of the first through hole 311g in the first upper surface 311a of the first base 311 in the z direction. be provided. At this time, the first capacitor element 551 faces the first connecting portion 313 in the y direction. The second capacitor element 552 faces the first connecting portion 313 and the first non-connecting portion 314 in the y direction. One of the two electrodes of first capacitor element 551 is joined to first electrode surface 312 a of first connecting portion 313 . One of the two electrodes of second capacitor element 552 is joined to first electrode surface 312 a of first connecting portion 313 and first non-connecting portion 314 .

Due to this connection configuration, the length of the conducting path between the first capacitor element 551 and the collector terminal 540a via the first electrode portion 312 and the first base portion 311 tends to be shortened. The length of the conducting path between the second capacitor element 552 and the collector terminal 540a via the first electrode portion 312 and the first base portion 311 tends to be longer.

As shown in FIG. 7, the insulating plate 640 is laminated on the P bus bar 303 in such a manner that the second lower surface faces the first upper surface 311a of the first base portion 311 of the P bus bar 303 in the z direction. With this lamination arrangement, a total of 10 second through holes 640g formed in the insulating plate 640 communicate with a total of 10 first through holes 311g formed in the P bus bar 303 in the z direction. A total of ten first connection portions 311h are inserted through a total of ten second through holes 640g.

At the same time, the collector terminal 540a of the seven-phase switch module is passed through seven of the ten second through holes 640g. In this embodiment, the collector terminals 540a are passed through the first to seventh second through holes 640g.

Moreover, in the above-described stacked arrangement, the portion of the insulating plate 640 where the third through hole 640h is formed is not opposed to the P bus bar 303 in the z direction. The emitter terminal 540b of the seven-phase switch module is passed through seven of the ten third through holes 640h. In this embodiment, the emitter terminals 540b are passed through the first to seventh third through holes 640h.

As shown in FIG. 8, the second base portion 315 of the N bus bar 304 is laminated on the insulating plate 640 such that the third lower surface faces the second upper surface 640a of the insulating plate 640 in the z-direction. With this stacking arrangement, a total of ten fourth through holes 315g formed in the N bus bar 304 communicate with a total of ten second through holes 640g formed in the insulating plate 640 in the z direction. A total of ten first connection portions 311h are inserted into a total of ten fourth through holes 315g.

At the same time, the collector terminal 540a of the seven-phase switch module is passed through seven of the ten fourth through holes 315g. In this embodiment, the collector terminal 540a is passed through the first to seventh fourth through holes 315g.

Further, due to the lamination arrangement described above, a total of ten fifth through holes 315h formed in the N bus bar 304 communicate with a total of ten third through holes 640h formed in the insulating plate 640 in the z direction.

At the same time, the emitter terminals 540b of the seven-phase switch module are passed through seven of the ten fifth through holes 315h. In this embodiment, the emitter terminals 540b are passed through the first to seventh fifth through holes 315h.

Specifically, the emitter terminals 540b of the U-phase switch module 531 to the W-phase switch module 533 are passed through the first to third fifth through holes 315h on the end side. The emitter terminal 540b of the A-phase switch module 530 is passed through the fourth fifth through hole 315h on the central side. The emitter terminals 540b of the X-phase switch module 534 to Z-phase switch module 536 are passed through the fifth to seventh fifth through holes 315h on the center side.

An emitter terminal 540b passing through the fifth through hole 315h protrudes above the third upper surface 315a in the z direction. The tip of the emitter terminal 540b protruding upward from the third upper surface 315a and the second connecting portion 315i are joined by laser irradiation so as to face each other in the x direction.

Further, as shown in FIG. 8, the second electrode portion 316 of the N bus bar 304 has the second electrode surface 316a opposed to the first capacitor element 551 and the second capacitor element 552 in the y direction. The other of the two electrodes of first capacitor element 551 is joined to second electrode surface 316 a of second connecting portion 317 . The other of the two electrodes of second capacitor element 552 is joined to second electrode surface 316 a of second connecting portion 317 and second non-connecting portion 318 .

Due to this connection configuration, the length of the conducting path between the first capacitor element 551 and the emitter terminal 540b via the second electrode portion 316 and the second base portion 315 tends to be shortened. The length of the conducting path between the second capacitor element 552 and the emitter terminal 540b via the second electrode portion 316 and the second base portion 315 tends to be longer.

<Improved versatility>
As described above, the P bus bar 303 has ten first through holes 311g and ten first connecting portions 311h for connecting to the seven collector terminals 540a. The N bus bar 304 has ten fifth through holes 315h and ten second connection portions 315i for connecting to the seven emitter terminals 540b. Also, the N bus bar 304 has ten fourth through holes 315g for passing the seven collector terminals 540a. The insulating plate 640 has ten second through holes 640g for passing the first connecting portion 311h and the collector terminal 540a, and ten third through holes 640h for passing the emitter terminal 540b.

Thus, the P bus bar 303 has more first through holes 311g and first connecting portions 311h than the total number of collector terminals 540a. The N bus bar 304 has more fifth through holes 315h and second connection portions 315i than the total number of emitter terminals 540b. Also, the N bus bar 304 has more fourth through holes 315g than the total number of collector terminals 540a. The insulating plate 640 has more second through holes 640g and third through holes 640h than the total number of collector terminals 540a (emitter terminals 540b).

According to this, even if the total number of collector terminals 540a and emitter terminals 540b increases as a result of an increase in the number of switch modules, the respective shapes of the P bus bar 303 and the N bus bar 304 and the insulating plate 640 can be changed. The switch module and the second capacitor 550 can be connected without any need. Thus, the versatility of each of the P bus bar 303 and the N bus bar 304 and the insulating plate 640 is improved with respect to changes in the number of switch modules.

<Inductance component>
By the way, the inductance component between the switch module and the second capacitor 550 via the P bus bar 303 and the N bus bar 304 has the property of increasing as the conducting path length of each of the P bus bar 303 and the N bus bar 304 increases. When the inductance component increases, the surge voltage generated when the current flowing through these bus bars changes with time increases.

In the P bus bar 303, the current flows between the connecting portion of the first connecting portion 311h with the collector terminal 540a and the connecting portion with the first electrode portion 312, one of the two electrodes of the first capacitor element 551. It flows through the first energization path. In addition, in P bus bar 303, the current flows between the connecting portion of first connection portion 311h with collector terminal 540a and the joint portion with first electrode portion 312, one of the two electrodes of second capacitor element 552. flows through the second current path.

The length of the conducting path between the switch module and the second capacitor 550 in the P bus bar 303 is the sum of the first conducting path and the second conducting path. Therefore, the inductance component between the switch module and the second capacitor 550 in the P bus bar 303 increases as the total value of the first energization path and the second energization path becomes longer.

In the N bus bar 304, the current flows between the connection portion of the second connection portion 315i with the emitter terminal 540b and the joint portion with the other second electrode portion 316 of the two electrodes of the first capacitor element 551. It flows through the third energization path. In N bus bar 304, the current flows between the connecting portion of second connection portion 315i with emitter terminal 540b and the joint portion with second electrode portion 316, the other of the two electrodes of second capacitor element 552. flows through the fourth energization path.

The length of the conducting path between the switch module and the second capacitor 550 in the N busbar 304 is the sum of the third conducting path and the fourth conducting path. Therefore, the inductance component between the switch module and the second capacitor 550 in the N bus bar 304 increases as the total value of the third energization path and the fourth energization path becomes longer.

As described above, the inductance component between the plurality of switch modules and the second capacitor 550 via the P bus bar 303 and the N bus bar 304 is the total energization current that is the sum of the first to fourth energization path lengths for each switch module. It increases as the path length increases.

As described above, in the present embodiment, the length of the conducting path between the first capacitor element 551 and the collector terminal 540a via the first electrode portion 312 and the first base portion 311 tends to be shortened. The length of the conducting path between the first capacitor element 551 and the emitter terminal 540b via the second electrode portion 316 and the second base portion 315 tends to be shortened.

Further, the length of the conducting path between the second capacitor element 552 and the collector terminal 540a via the first electrode portion 312 and the first base portion 311 tends to increase. The length of the conducting path between the second capacitor element 552 and the emitter terminal 540b via the second electrode portion 316 and the second base portion 315 tends to increase.

Each of the first connection portion 311h and the second connection portion 315i with the lower number is farther from the second capacitor element 552 than the first connection portion 311h and the second connection portion 315i with the higher number in the current path in the bus bar. ing.

As described above, in the case of the connection form of the first capacitor element 551 and the second capacitor element 552 with respect to the P bus bar 303 and the N bus bar 304 exemplified in this embodiment, the total conducting path length is When the terminal of the terminal is connected, it tends to be long. The total conducting path length is likely to be longer when switch module terminals are connected only to low-numbered connections than when switch module terminals are connected only to medium-numbered connections. It's becoming As a specific example, the lowest numbers are the first to the third. Medium numbers are 4th to 7th. And the highest number is from 8th to 10th.

On the other hand, in this embodiment, the collector terminals 540a are connected to the first to seventh first connection portions 311h. The emitter terminals 540b are connected to the first to seventh second connection portions 315i.

Specifically, collector terminals 540a and emitter terminals 540b of the U-phase switch module 531 to W-phase switch module 533 are connected to the first to third first connection portions 311h and second connection portions 315i. A collector terminal 540a and an emitter terminal 540b of the A-phase switch module 530 are connected to the fourth first connection portion 311h and second connection portion 315i. Collector terminals 540a and emitter terminals 540b of the X-phase switch module 534 to Z-phase switch module 536 are connected to the fifth to seventh first connection portions 311h and second connection portions 315i.

Therefore, the total conducting path length between the U-phase to W-phase switch modules and the second capacitor 550 tends to be longer than the total conducting path length between the X-phase to Z-phase switch modules and the second capacitor 550. It's becoming The inductance component between the U-phase to W-phase switch modules and the second capacitor 550 tends to be higher than the inductance component between the X-phase to Z-phase switch modules and the second capacitor 550 .

Therefore, if the switching speed of the high-side switch 541 and the low-side switch 542 included in the U-phase to W-phase switch modules is increased, the surge voltage generated in this switch module tends to increase. Therefore, it is conceivable to suppress the increase in surge voltage by delaying the switching speed of these switches. However, in this case, there arises a new problem of temperature rise due to an increase in switching loss.

On the other hand, in the present embodiment, the U-phase to W-phase switch modules are located upstream of the refrigerant from the X-phase to Z-phase switch modules. Therefore, the U-phase to W-phase switch modules are more easily cooled by the refrigerant than the X-phase to Z-phase switch modules. Therefore, even if the surge voltage rise is suppressed by delaying the switching speed of the switches included in the U-phase to W-phase switch modules, temperature rise in the switch modules is suppressed.

Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present disclosure.

(First modification)
In this embodiment, an example in which seven switch modules are accommodated in the cooler 610 is shown. However, for example, nine switch modules may be housed in cooler 610 as shown in FIG. Even if the number of switch modules increases in this way, the nine switch modules and the second capacitor 550 can be connected via these bus bars without changing the shape of each of the P bus bar 303 and the N bus bar 304. can. In FIG. 9, reference numeral 536 is assigned to the new switch module in order to suppress an increase in reference numerals.

Also, as shown in FIG. 10, cooler 610 may house four switch modules. Even in such a configuration, the four switch modules and the second capacitor 550 can be connected via these bus bars without changing the shape of each of the P bus bar 303 and the N bus bar 304 .

(Second modification)
In this embodiment, the example in which the collector terminals 540a are connected to the first to seventh first connection portions 311h is shown. An example is shown in which the emitter terminals 540b are connected to the first to seventh second connection portions 315i. However, the terminals of the switch module may be connected to any number of connecting portions.

For example, in the modification shown in FIG. 11, collector terminals 540a are connected to second to eighth first connection portions 311h, and emitter terminals 540b are connected to second to eighth second connection portions 315i. It is connected. In the modification shown in FIG. 12, collector terminals 540a are connected to fourth to seventh first connection portions 311h, and emitter terminals 540b are connected to fourth to seventh second connection portions 315i. It is

In this way, the terminal of the switch module may be connected to any connection part, but the connection that shortens the total current path length between the switch module and the second capacitor 550 via the P bus bar 303 and the N bus bar 304 is used. It is preferable to select the part as a connection target.

As described in the present embodiment, the total conducting path length of the P bus bar 303 and the N bus bar 304 tends to become longer when the terminal of the switch module is connected to the lower numbered connection portion. Specifically, for example, when the collector terminal 540a is connected to the first connection portion 311h and the emitter terminal 540b is connected to the first second connection portion 315i, the total conducting path length tends to be long. It's becoming

11 and 12, the terminals of the switch module are not connected to the first connecting portion 311h and the second connecting portion 315i. Therefore, the total conducting path length between the plurality of switch modules and the second capacitor 550 via the P bus bar 303 and the N bus bar 304 tends to be shortened. The inductance component between the plurality of switch modules and second capacitor 550 via P bus bar 303 and N bus bar 304 tends to decrease.

As a matter of course, each of the first connection portion 311h and the second connection portion 315i with the higher number has a higher energization path length than the first connection portion 311h and the second connection portion 315i with the lower number. away from the first capacitor element 551; Therefore, if a bus bar is connected to a connection portion with a high number, the total conducting path length tends to become long. The total conducting path length is likely to be longer when switch module terminals are connected only to high-numbered connections than when switch module terminals are connected only to medium-numbered connections. It's becoming

In order to avoid this, especially in the modification shown in FIG. 12, the collector terminals 540a are connected to the fourth to seventh middle first connection portions 311h, and the fourth to seventh first connection portions 311h are connected to the collector terminals 540a. An emitter terminal 540b is connected to the second connection portion 315i. In this way, the terminals of the switch module may be disconnected from the connection portion where the conducting path length tends to be long. More specifically, the terminal of the switch module may be disconnected from the terminal of the switch module, which tends to have the longest conducting path. This reduces the surge voltage caused by the inductance component.

Also, although not shown, the collector terminal 540a is connected to the fifth to eighth first connection portions 311h on the middle to high number side, and the fifth to eighth second connection portions 311h are connected to the collector terminal 540a. An emitter terminal 540b may be connected to 315i. The collector terminal 540a is connected to the third to sixth first connection portions 311h from the low-to-middle number side, and the emitter terminal 540b is connected to the third to sixth second connection portions 315i. may be Terminals of the switch module may be connected to the connection portions on both ends. The number N1 of non-connections to the terminals of the lower-numbered connection portion and the number N2 of non-connections to the terminals of the higher-numbered connection portion may be equal to or different from each other.

In other words, the terminals of the switch module are connected to the low-numbered connection portion and the high-numbered connection portion located at both ends, and the middle-numbered connection portion located in the center. A configuration in which at least one of the terminals is not connected to the terminal can also be adopted.

(Third modification)
In this embodiment, the example in which the P bus bar 303 has ten first through holes 311g and ten first connecting portions 311h is shown. An example in which the insulating plate 640 has ten second through holes 640g and ten third through holes 640h is shown. An example in which the N bus bar 304 has ten fourth through holes 315g, fifth through holes 315h, and ten second connection portions 315i is shown. However, the number of through-holes and connecting portions is not limited to the above example. It may be larger than the total number of collector terminals 540a (emitter terminals 540b) of a plurality of switch modules that are assumed to be connected.

(Fourth modification)
In the present embodiment, the other of the two side surfaces extending in the z direction on the plane facing the y direction of the first connecting portion 313 is the first front surface 311e of the first base portion 311 on the plane facing the x direction. An example of continuous connection is shown. However, this side surface and the first front surface 311e do not have to be continuously connected in the plane facing the x direction.

Similarly, in this embodiment, the other of the two side surfaces extending in the z direction on the plane facing the y direction of the second connecting portion 317 is the third front surface 315e of the second base portion 315 and the x direction. An example of continuous connection in the facing plane is shown. However, this side surface and the third front surface 315e do not have to be continuous in the plane facing the x-direction. For example, the two surfaces may be discontinuous in the plane facing the x-direction because the positions of these two surfaces in the x-direction are different.

(Fifth Modification)
In this embodiment, the high-side switch 541 and the low-side switch 542, and the high-side diode 541a and the low-side diode 542a are covered and protected by the sealing resin 543 to form one switch module.

However, unlike this, for example, the high-side switch 541 and the high-side diode 541a may be resin-sealed to form one switch module. The low-side switch 542 and the low-side diode 542a may be resin-sealed to form one switch module. The configuration form of the switch module is not particularly limited.

(Other modifications)
In this embodiment, an example in which the power conversion unit 300 has all the components of the power converter 500 is shown. However, power conversion unit 300 only needs to include one component of converter 501 and inverter 502 . Alternatively, power conversion unit 300 may include some components of converter 501 and inverter 502 . It is sufficient that at least the power conversion unit 300 includes the second capacitor 550 and a plurality of switch modules as components of the power conversion device 500 .

In this embodiment, an example in which the power conversion unit 300 is included in the vehicle-mounted system 100 for an electric vehicle is shown. However, application of the power conversion unit 300 is not particularly limited to the above example. For example, a configuration in which power conversion unit 300 is included in a hybrid system that includes a motor and an internal combustion engine may be employed.

In this embodiment, the motor 400 has shown the example which has two 1st MG401 and 2nd MG402. However, a configuration in which motor 400 has a single MG can also be adopted. In this case, the inverter 502 of the power conversion unit 300 has at least three phase switch modules.

DESCRIPTION OF SYMBOLS 100... Vehicle-mounted system, 200... Battery, 300... Power conversion unit, 303... P bus bar, 304... N bus bar, 311... First base, 311 g... First through hole, 311 h... First connection part, 312... First electrode Part 315...Second base 315g...Fourth through hole 315h...Fifth through hole 315i...Second connection part 315...Second electrode part 400...Motor 500...Power converter 530...A phase Switch module 531 U-phase switch module 532 V-phase switch module 533 W-phase switch module 534 X-phase switch module 535 Y-phase switch module 536 Z-phase switch module 540a Collector terminal 540b... emitter terminal, 550... second capacitor, 610... cooler, 611... supply pipe, 611a... supply port, 612... discharge pipe, 613... relay pipe

Claims (4)

a plurality of switch modules (530 to 536) arranged in the arrangement direction;
busbars (303, 304) exposed from upper surfaces (543e) of the plurality of switch modules and connected to the plurality of connection terminals (540a, 540b) arranged in the arrangement direction ;
a capacitor (550) connected to each of the plurality of switch modules via the bus bar;
The busbar includes: a plurality of connection portions (311h, 315i) arranged in the arrangement direction , the number of which is greater than the total number of the connection terminals; base portions (311, 315) that integrally connect the plurality of connection portions; an electrode portion (312, 316) integrally coupled to the base portion and connected to the electrodes of the capacitor ;
The base is provided above the upper surface in a manner facing the upper surface,
the base has a plurality of through holes (311g, 315h) arranged in the arrangement direction, the number of which is greater than the total number of the connection terminals;
Each of the connection portions rises upward from a side wall defining the through hole,
the connection terminals are respectively passed through some of the plurality of through holes,
A power conversion unit in which the plurality of connection terminals are connected to some of the plurality of connection portions. 2. The electric power according to claim 1 , wherein, among the plurality of connection portions, the connection portion having the longest conducting path length from the electrode through the base portion and the electrode portion is disconnected from the connection terminal. conversion unit. A plurality of the connection portions are arranged in the arrangement direction,
Among the plurality of connection portions arranged in the arrangement direction, the length of the conducting path through the base portion and the electrode portion between the connection portions located on both end sides and the electrodes is the connection portion located on the center side. 3. The power conversion unit according to claim 1 or 2, wherein the power conversion unit is longer than the length of a conducting path between the base and the electrode through the base and the electrode. a cooler (610) for housing and cooling each of the plurality of switch modules;
The cooler includes a plurality of relay pipes (613) that are spaced apart in the arrangement direction to form a gap for housing the switch module, and a supply pipe (611) that supplies coolant to each of the plurality of relay pipes. and a discharge pipe (612) for discharging the refrigerant that has flowed through each of the plurality of relay pipes,
4. The power conversion unit according to claim 3 , wherein a supply port (611a) to which the coolant is supplied from the outside in the supply pipe is positioned on one side of both ends of the plurality of connection portions arranged in the arrangement direction. .

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