Power converter

Abstract

To provide a power converter in which a switch can be prevented from causing malfunctions.SOLUTION: An inverter 100 has a U-phase leg group and a U-phase bus bar 71. The U-phase leg group includes two U-phase legs 21 and 22 which drive at the same potential. The U-phase legs 21 and 22 each have a second high-side switch 31 and a second low-side switch 32 serially connected to each other. The U-phase bus bar 71 is connected between the second high-side switch 31 and the second low-side switch 32 of the U-phases 21 and 22. Also, a space of the U-phase legs 21 and 22 between the second high-side switch 31 and the second low-side switch 32 is connected in parallel to the U-phase bas bar 71.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a power conversion device. [Background technology]

[0002] As shown in Patent Document 1, there is a power conversion device including a U-phase leg group, a V-phase leg group, and a W-phase leg group. Each phase leg group includes a plurality of phase legs including a high-side switch and a low-side switch connected in series. For example, the plurality of U-phase legs in the U-phase leg group are connected to a motor via a phase bus bar between the high-side switch and the low-side switch. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-167786 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the power conversion device, for example, the voltage between the high-side switch and the low-side switch of one U-phase leg and the voltage between the high-side switch and the low-side switch of another U-phase leg may fluctuate, and therefore, in the power conversion device, there is a risk that a malfunction will occur in the high-side switch due to the voltage fluctuation.

[0005] In view of the above, an object of the disclosure described in this specification is to provide a power conversion device capable of suppressing switch malfunctions. [Means for solving the problem]

[0006] The power conversion device disclosed herein is A plurality of semiconductor devices (21 to 26) each having an output terminal (21a to 26a) and driven at the same potential; output wiring (71a to 73a) commonly connected between output terminals of the plurality of semiconductor devices; Each semiconductor device includes a high-side switch (31) and a low-side switch (32) connected in series; The output wiring is connected between the high-side switch and the low-side switch of each semiconductor device, The high-side switch and the low-side switch of each semiconductor device are connected in parallel to the output wiring.

[0007] Therefore, the power conversion device can reduce the impedance between the multiple semiconductor devices, and therefore the power conversion device can suppress voltage fluctuations between the multiple semiconductor devices, and therefore the power conversion device can suppress malfunctions of the high-side switch caused by voltage fluctuations.

[0008] It should be noted that the reference numbers in parentheses above merely indicate the corresponding relationship with the configurations described in the embodiments described below, and do not in any way limit the technical scope. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is an electrical circuit diagram of the in-vehicle system. [Diagram 2] FIG. 2 is a plan view showing a schematic configuration of a semiconductor module. [Diagram 3] FIG. 2 is a plan view showing a schematic configuration of a power conversion unit. [Figure 4] 2 is a plan view showing a schematic configuration of a power conversion unit on a circuit board side. FIG. [Diagram 5] FIG. 2 is a perspective view showing a schematic configuration of a bus bar. [Figure 6] FIG. 2 is a plan view showing a schematic configuration of a bus bar. [Figure 7] 11 is a plan view showing a schematic configuration of a bus bar according to Modification 1. FIG. [Figure 8] 11 is a plan view showing a schematic configuration of a bus bar according to Modification 2. FIG. [Figure 9] 13 is a plan view showing a schematic configuration of a bus bar according to Modification 3. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment will be described with reference to the drawings.

[0011] (First embodiment) In this embodiment, an example in which the power conversion device is applied to an inverter 100 is adopted. The inverter 100 will be described with reference to Figs. 1 to 6. In this embodiment, as an example, an example in which the inverter 100 is provided in a power conversion unit 1 is adopted. Moreover, the power conversion unit 1 is provided in an in-vehicle system 1000. Therefore, hereinafter, the power conversion unit 1 and the in-vehicle system 1000 will also be described.

[0012] <In-vehicle systems> The in-vehicle system 1000 constitutes a system for an electric vehicle. As shown in FIG.

[0013] The in-vehicle system 1000 may have multiple ECUs (not shown). These multiple ECUs transmit and receive signals to each other via a bus line. The multiple ECUs cooperate to control the electric vehicle. Regeneration and power running of the motor 600 are controlled according to the SOC of the battery 500 by the control of the multiple ECUs. SOC is an abbreviation for state of charge. ECU is an abbreviation for electronic control unit.

[0014] The battery 500 includes a plurality of secondary batteries. The plurality of secondary batteries are connected in series to form a battery stack. The SOC of this battery stack corresponds to the SOC of the battery 500. As the secondary batteries, a lithium ion secondary battery, a nickel-metal hydride secondary battery, an organic radical battery, or the like can be used.

[0015] The power conversion unit 1 performs power conversion between the battery 500 and the motor 600. The power conversion unit 1 converts the DC power of the battery 500 into AC power at a voltage level suitable for powering the motor 600. The power conversion unit 1 converts the AC power generated by power generation (regeneration) of the motor 600 into DC power at a voltage level suitable for charging the battery 500. The configuration of the power conversion unit 1 will be described in detail later.

[0016] The motor 600 is connected to an output shaft of an electric vehicle (not shown). The rotational energy of the motor 600 is transmitted to the running wheels of the electric vehicle via the output shaft. Conversely, the rotational energy of the running wheels is transmitted to the motor 600 via the output shaft.

[0017] The motor 600 is powered by AC power supplied from the power conversion unit 1. This provides a propulsive force to the running wheels. The motor 600 also regenerates power using the rotational energy transmitted from the running wheels. The AC power generated by this regeneration is converted to DC power and reduced in voltage by the power conversion unit 1. This DC power is supplied to the battery 500. The DC power is also supplied to various electrical loads mounted on the electric vehicle.

[0018] <Power conversion unit> As shown in Fig. 1, the power conversion unit 1 includes an inverter 100 and a converter 200. Here, the electrical connection relationship between the inverter 100 and the converter 200 will be mainly described. The configurations of the inverter 100 and the converter 200 will be described later with reference to Fig. 3 and the like. It is noted that the power conversion unit 1 does not necessarily have to include the converter 200.

[0019] The inverter 100 is electrically connected to the U-phase stator coil, the V-phase stator coil, and the W-phase stator coil of the motor 600 via a U-phase bus bar 71, a V-phase bus bar 72, and a phase bus bar 73.

[0020] Converter 200 boosts the DC power of battery 500 to a voltage level suitable for powering motor 600. Inverter 100 converts this DC power to AC power. This AC power is supplied to motor 600. Inverter 100 also converts the AC power generated by motor 600 to DC power. Converter 200 reduces the DC power to a voltage level suitable for charging battery 500.

[0021] The converter 200 is electrically connected to the battery 500 via a first power supply bus bar 401 and a second power supply bus bar 402. The converter 200 is electrically connected to the inverter 100 via a third power supply bus bar 403 and a fourth power supply bus bar 404.

[0022] The first power supply bus bar 401 is connected to the positive electrode of the battery 500. The second power supply bus bar 402 is connected to the negative electrode of the battery 500. A first capacitor 51 is connected to the first power supply bus bar 401 and the second power supply bus bar 402. One of two electrodes of the first capacitor 51 is connected to the first power supply bus bar 401, and the other is connected to the second power supply bus bar 402.

[0023] The third power supply bus bar 403 is connected to a first high-side switch 37 described later. The fourth power supply bus bar 404 is connected to the second power supply bus bar 402. The third power supply bus bar 403 and the fourth power supply bus bar 404 are connected to a second capacitor 52. One of two electrodes of the second capacitor 52 is connected to the third power supply bus bar 403, and the other is connected to the fourth power supply bus bar 404.

[0024] <Converter> The converter 200 has an A-phase leg 27 and a reactor 220. The A-phase leg 27 has a first high-side switch 37 and a first low-side switch 38. In this embodiment, as an example, MOSFETs are used for the first high-side switch 37 and the first low-side switch 38. Note that IGBTs may also be used for the first high-side switch 37 and the first low-side switch 38. Also, for the switch group 10 described later, IGBTs may be used instead of MOSFETs.

[0025] The first high-side switch 37 and the first low-side switch 38 are each sealed with resin. This configures the A-phase leg 27 as a semiconductor module. The semiconductor module is configured in the same manner as the first U-phase leg 21 of FIG.

[0026] The A-phase leg 27 includes a midpoint terminal 27a, an A-phase drain terminal 27b, and an A-phase source terminal 27c. The midpoint terminal 27a is connected to a source electrode of the first high-side switch 37 and a drain electrode of the first low-side switch 38. The A-phase drain terminal 27b is connected to the drain electrode of the first high-side switch 37. The A-phase source terminal 27c is connected to the source electrode of the first low-side switch 38.

[0027] The midpoint terminal 27a is connected to the first power supply bus bar 401. The A-phase drain terminal 27b is connected to the third power supply bus bar 403. The A-phase source terminal 27c is connected to the second power supply bus bar 402. Therefore, the first high-side switch 37 and the first low-side switch 38 are connected in series in this order from the third power supply bus bar 403 to the second power supply bus bar 402. A reactor 220 is connected to the first power supply bus bar 401.

[0028] The first high-side switch 37 and the first low-side switch 38 are controlled to be opened or closed by the ECU. The ECU generates a control signal and outputs it to the gate driver. The gate driver amplifies the control signal and outputs it to the gate electrodes of the switches 37, 38. In this way, the ECU increases or decreases the voltage level of the DC power input to the converter 200. The gate electrodes of the switches 37, 38 are connected to one of signal terminals 21d, 21e, which will be described later.

[0029] The ECU generates a pulse signal as a control signal. The ECU adjusts the on-duty ratio and frequency of this pulse signal to adjust the step-up / step-down level of the DC power. In this way, the ECU performs PWM control of the switch. The step-up / step-down level is determined according to the target torque of the motor 600 and the SOC of the battery 500.

[0030] When boosting the DC power of the battery 500, the ECU alternately opens and closes the first high-side switch 37 and the first low-side switch 38. Conversely, when lowering the DC power supplied from the inverter 100, the ECU fixes the control signal output to the first low-side switch 38 at a low level. At the same time, the ECU switches the control signal output to the first high-side switch 37 between a high level and a low level in sequence.

[0031] <Inverter> The inverter 100 includes a switch group 10 consisting of a U-phase leg group, a V-phase leg group, and a W-phase leg group.

[0032] The U-phase leg group has a first U-phase leg 21 and a second U-phase leg 22. In addition, it can be said that the U-phase leg group includes the first U-phase leg 21 and the second U-phase leg 22 that are driven at the same potential.

[0033] The first U-phase leg 21 and the second U-phase leg 22 each have a second high-side switch 31 and a second low-side switch 32. The second high-side switch 31 and the second low-side switch 32 are each a MOSFET. Note that the second high-side switch 31 and the second low-side switch 32 employ MOSFETs whose main component is SiC. However, the second high-side switch 31 and the second low-side switch 32 may also employ MOSFETs whose main component is Si.

[0034] In this embodiment, a U-phase leg group including two legs 21 and 22 is used. However, the present disclosure can also be used for a U-phase leg group including three or more legs. This also applies to the V-phase leg group and the W-phase leg group.

[0035] The first U-phase leg 21 includes a first motor terminal 21a, a first drain terminal 21b, and a first source terminal 21c. The first motor terminal 21a is connected to a source electrode of the second high-side switch 31 and a drain electrode of the second low-side switch 32 in the first U-phase leg 21. The first drain terminal 21b is connected to a drain electrode of the second high-side switch 31 in the first U-phase leg 21. The first source terminal 21c is connected to a source electrode of the second low-side switch 32 in the first U-phase leg 21. In the following, the first motor terminal 21a, the first drain terminal 21b, and the first source terminal 21c are also collectively referred to as main terminals 21a to 21c.

[0036] Furthermore, the first U-phase leg 21 includes a plurality of signal terminals 21d connected to the second high-side switch 31 and a plurality of signal terminals 21e connected to the second low-side switch 32. One of each of the signal terminals 21d, 21e is connected to the gate electrodes of each of the switches 31, 32. Furthermore, the first U-phase leg 21 includes a first suspension lead 21f.

[0037] The second U-phase leg 22 includes a second motor terminal 22a, a second drain terminal 22b, and a second source terminal 22c. The second motor terminal 22a is connected to a source electrode of the second high-side switch 31 and a drain electrode of the second low-side switch 32 in the second U-phase leg 22. The second drain terminal 22b is connected to a drain electrode of the second high-side switch 31 in the second U-phase leg 22. The second source terminal 22c is connected to a source electrode of the second low-side switch 32 in the second U-phase leg 22. The second U-phase leg 22 includes signal terminals 21d and 21e and a second suspension lead 22f, similar to the first U-phase leg 21. The first suspension lead 21f will be described in detail later.

[0038] The first drain terminal 21b and the second drain terminal 22b are connected to a third power supply bus bar 403. The first source terminal 21c and the second source terminal 22c are connected to a fourth power supply bus bar 404. The first motor terminal 21a and the second motor terminal 22a are connected to a U-phase bus bar 71. The first motor terminal 21a and the second motor terminal 22a correspond to output terminals electrically connected to each other.

[0039] The second high-side switches 31 and the second low-side switches 32 of the phase legs 21, 22 are connected in series in this order from the third power supply bus bar 403 toward the fourth power supply bus bar 404. The two second high-side switches 31 are connected in parallel. The two second low-side switches 32 are connected in parallel.

[0040] The phase legs 21, 22 constitute a semiconductor module shown in Fig. 2. The first U-phase leg 21 and the second U-phase leg 22 of the semiconductor module have the same configuration. Furthermore, the legs 23 to 26 described later also have the same configuration. Therefore, hereinafter, the semiconductor module will be described using the first U-phase leg 21. The semiconductor module corresponds to a semiconductor device.

[0041] The semiconductor module includes the switches 31, 32, the terminals 21a to 21e, and insulating resin 21g that seals these. The semiconductor module also includes a first suspension lead 21f that is sealed with the insulating resin 21g. In the semiconductor module, the terminals 21a to 21e and the first suspension lead 21f are partially exposed from the insulating resin 21g.

[0042] In the semiconductor module, the main terminals 21a to 21c partially protrude from the first side surface 21g1 of the insulating resin 21g. In addition, in the semiconductor module, the signal terminals 21d, 21e and the first suspension lead 21f partially protrude from the second side surface 21g2 of the insulating resin 21g. The second side surface 21g2 is the opposite surface to the first side surface 21g1. Therefore, it can be said that the suspension lead 21f protrudes in a direction different from that of the main terminals 21a to 21c. The first motor terminal 21a, the first drain terminal 21b, and the first source terminal 21c are arranged side by side in the X direction. The signal terminals 21d, 21e and the first suspension lead 21f are also arranged side by side in the X direction. The X direction can also be said to be the arrangement direction. The insulating resin portion 21g corresponds to the main body portion.

[0043] The terminals 21a to 21e and the first suspension lead 21f are part of a lead frame. The lead frame includes an island on which the switches 31 and 32 are mounted, and terminal portions that become the terminals 21a to 21e. The lead frame further includes the first suspension lead 21f that connects the island and the terminals 21d and 21e until halfway through the manufacturing process of the semiconductor module.

[0044] In addition, the island on which the second high-side switch 31 is mounted is electrically connected to the terminal portion that becomes the first drain terminal 21b. The island on which the second low-side switch 32 is mounted is electrically connected to the terminal portion that becomes the first motor terminal 21a and the first suspension lead 21f. In other words, the terminal portion that becomes the first drain terminal 21b is connected to the island on which the second high-side switch 31 is mounted. In addition, the terminal portion that becomes the first motor terminal 21a and the first suspension lead 21f are connected to the island on which the second low-side switch 32 is mounted.

[0045] The first suspension lead 21f is connected to the source electrode of the second high-side switch 31 and the drain electrode of the second low-side switch 32. For this reason, the first suspension lead 21f can be said to have the same potential as the first motor terminal 21a.

[0046] 1, the second U-phase leg 22 includes a second suspension lead 22f, similar to the first U-phase leg 21. Therefore, it can be said that the second suspension lead 22f is connected to the source electrode of the second high-side switch 31 and the drain electrode of the second low-side switch 32 in the second U-phase leg 22. Therefore, the second suspension lead 22f has the same potential as the second motor terminal 22a.

[0047] 1 , in the inverter 100, between the second high-side switch 31 and the second low-side switch 32 of the first U-phase leg 21 and between the second high-side switch 31 and the second low-side switch 32 of the second U-phase leg 22 are connected to the motor 600. Between the second high-side switch 31 and the second low-side switch 32 of the first U-phase leg 21 can also be considered as between the upper and lower switches of the first U-phase leg 21. Similarly, between the second high-side switch 31 and the second low-side switch 32 of the second U-phase leg 22 can also be considered as between the upper and lower switches of the second U-phase leg 22.

[0048] Furthermore, in the inverter 100, the upper and lower switches of the first U-phase leg 21 and the upper and lower switches of the second U-phase leg 22 are connected in parallel to a wiring 71a connected to the motor 600 by one or more wirings. The wiring 71a connected to the motor 600 connects the first motor terminal 21a and the second motor terminal 22a. The wiring 71a corresponds to an output wiring. The wiring 71a also includes a connection terminal 81 of the U-phase bus bar 71.

[0049] In this embodiment, as an example of a configuration for parallel connection, an example using the first suspension lead 21f, the second suspension lead 22f, and the bus bar 60 is adopted. The first suspension lead 21f and the second suspension lead 22f are electrically connected by the bus bar 60. In other words, the bus bar 60 connects the switches of the first U-phase leg 21 and the switches of the second U-phase leg 22 in parallel to the wiring connected to the motor 600. However, the present disclosure is not limited to this. The first suspension lead 21f and the second suspension lead 22f may be directly connected without the bus bar 60. The same applies to the other suspension leads 23f, 24f and the suspension leads 25f, 26f.

[0050] It can also be said that the bus bar 60 connects the first suspension lead 21f, which has the same potential as the first motor terminal 21a, and the second suspension lead 22f, which has the same potential as the second motor terminal 22a. It can also be said that the bus bar 60 shorts the suspension leads 21f, 22f. Each suspension lead 21f, 22f can also be said to be a parallel connection terminal, a potential fixed terminal, a same potential terminal, or the like. Furthermore, it can also be said that the bus bar 60 connects the first motor terminal 21a and the second motor terminal 22a to each other separately from the output wiring. Also, it can be said that the inverter 100 is provided with a parallel connection circuit for the output wiring in terms of circuitry.

[0051] In the semiconductor module, only the main terminals 21a-21c can be formed on the first side surface 21g1. Therefore, the semiconductor module can employ the main terminals 21a-21c that are wider than the signal terminals 21d, 21e, etc. Also, the main terminals 21a-21c are wider (larger) than the first suspension lead 21f.

[0052] It can also be said that the bus bar 60 is provided to reduce the source-to-source impedance between the first U-phase leg 21 and the second U-phase leg 22. It can also be said that the bus bar 60 is provided to suppress the source-to-source potential fluctuation between the first U-phase leg 21 and the second U-phase leg 22. It can also be said that the bus bar 60 is provided to reduce the source-to-source impedance between the same-phase semiconductor modules and suppress the source-to-source voltage fluctuation. The source voltage fluctuation is a fluctuation in the source-to-source voltage Vs.

[0053] The impedance of the bus bar 60 is preferably equal to or lower than the impedance of the U-phase bus bar 71. This makes it easier for the bus bar 60 to reduce the source-to-source impedance between the first U-phase leg 21 and the second U-phase leg 22.

[0054] The bus bars 60 and the connection configuration using the bus bars 60 are similar to those of the V-phase leg group and the W-phase leg group, which will be described later. The structure of the bus bars 60 will be described in detail later.

[0055] The V-phase leg group and the W-phase leg group are configured similarly to the U-phase leg group, and the following mainly describes the differences from the U-phase leg group.

[0056] The V-phase leg group has a first V-phase leg 23 and a second V-phase leg 24 driven at the same potential. The first V-phase leg 23 and the second V-phase leg 24 each have a third high-side switch 33 and a third low-side switch 34. The first V-phase leg 23 includes a third motor terminal 23a, a third drain terminal 23b, a third source terminal 23c, signal terminals 21d and 21e, and a third suspension lead 23f.

[0057] The second V-phase leg 24 includes a fourth motor terminal 24a, a third drain terminal 24b, a fourth source terminal 24c, signal terminals 21d and 21e, and a fourth suspension lead 24f. The third motor terminal 23a and the fourth motor terminal 24a are connected to a V-phase bus bar 72. The third motor terminal 23a and the fourth motor terminal 24a correspond to output terminals electrically connected to each other.

[0058] The upper and lower switches of the first V-phase leg 23 and the upper and lower switches of the second V-phase leg 24 are connected in parallel to a wiring 72a connected to the motor 600 by one or more wirings. The wiring 72a connected to the motor 600 connects the third motor terminal 23a and the fourth motor terminal 24a. The wiring 72a corresponds to an output wiring. The wiring 72a also includes a connection terminal 81 of the V-phase bus bar 72.

[0059] The W-phase leg group has a first W-phase leg 25 and a second W-phase leg 26 driven at the same potential. The first W-phase leg 25 and the second W-phase leg 26 each have a fourth high-side switch 35 and a fourth low-side switch 36. The first W-phase leg 25 includes a fifth motor terminal 25a, a fifth drain terminal 25b, a fifth source terminal 25c, signal terminals 21d and 21e, and a fifth suspension lead 25f.

[0060] The second W-phase leg 26 includes a sixth motor terminal 26a, a sixth drain terminal 26b, a sixth source terminal 26c, signal terminals 21d and 21e, and a sixth suspension lead 26f. The fifth motor terminal 25a and the sixth motor terminal 26a are connected to a W-phase bus bar 73. The fifth motor terminal 25a and the sixth motor terminal 26a correspond to output terminals electrically connected to each other. The motor terminals 21a to 26a correspond to output terminals.

[0061] The upper and lower switches of the first W-phase leg 25 and the upper and lower switches of the second W-phase leg 26 are connected in parallel to a wiring 73a connected to the motor 600 by one or more wirings. The wiring 73a connected to the motor 600 connects the fifth motor terminal 25a and the sixth motor terminal 26a. The wiring 73a corresponds to an output wiring. The wiring 73a also includes a connection terminal 81 of the W-phase bus bar 73.

[0062] The first U-phase leg 21 and the second U-phase leg 22 can also be called in-phase legs. Similarly, the first V-phase leg 23 and the second V-phase leg 24 are in-phase legs, and the first W-phase leg 25 and the second W-phase leg 26 are in-phase legs.

[0063] The U-phase bus bar 71, the V-phase bus bar 72, and the W-phase bus bar 73 are each provided in a second connector 13b shown in Fig. 3. A wire harness or the like is connected to the second connector 13b. Each of the phase bus bars 71 to 73 is connected to a three-phase stator coil of the U-phase to W-phase of the motor 600 via the wire harness.

[0064] Each of the phase bus bars 71 to 73 is provided with a current sensor 80. Each of the phase bus bars 71 to 73 and the current sensor 80 are insert-molded into a resin terminal block 180 shown in FIG.

[0065] The inverter 100 has three-phase leg groups of U-phase to W-phase corresponding to the three-phase stator coils of the motor 600, respectively. A control signal, the signal strength of which is amplified by a gate driver, is input to the gate electrodes of the switches 31 to 36 of each of these three-phase leg groups.

[0066] When the motor 600 is powered, the switch is PWM-controlled by the output of a control signal from the ECU. This generates a three-phase AC current in the inverter 100. When the motor 600 generates (regenerates), the ECU, for example, stops outputting the control signal. As a result, the AC power is converted into DC power.

[0067] 4, the signal terminals 21d, 21e of the phase legs 21 to 27 are connected to a circuit board 90. More specifically, the signal terminals 21d, 21e are electrically connected to wiring on the circuit board 90. A control signal of the ECU is input via the circuit board 90.

[0068] As described above, the signal terminals 21d, 21e, etc. protrude in the opposite direction to the main terminals 21a to 21c. Therefore, the circuit board 90 is provided on the opposite side in the Z direction to the terminal block 180, etc. shown in Fig. 3. Therefore, Fig. 4 can be said to show a part of the opposite side in the Z direction to Fig. 3.

[0069] Further, the semiconductor module is provided with a first suspension lead 21f aligned with the signal terminals 21d, 21e. Therefore, in the present embodiment, as an example, an example is adopted in which the first suspension leads 21f-26f are arranged in the opposing region of the circuit board 90. Therefore, each bus bar 60 is arranged in the opposing region of the circuit board 90. That is, each bus bar 60 is arranged between each semiconductor module (insulating resin 21g) and the circuit board 90. This makes it possible to effectively utilize the dead space between the insulating resin 21g and the circuit board 90. It is possible to prevent the inverter 100 from becoming large in size. However, the position of the bus bar 60 is not limited to this.

[0070] <Power module> The power conversion unit 1 has a cooler 14 shown in Fig. 3 in addition to the circuit elements described above. The cooler 14 holds and cools the phase legs 21 to 27. The phase legs 21 to 27 and the cooler 14 constitute a power module 300. The cooler 14 is pressed by a spring body 11 fixed to the housing 12. However, in the present disclosure, the spring body 11 does not necessarily have to be provided.

[0071] In addition, the power module 300 is shown as an area surrounded by a dashed line in Fig. 1. For convenience of notation, the second capacitor 52 is included in the area surrounded by the dashed line indicating the power module 300 in Fig. 1. Strictly speaking, the inclusion relationship is not included in the power module 300.

[0072] As shown in Fig. 3, the cooler 14 has a supply pipe 14a, a discharge pipe 14b, and multiple relay pipes 14c. The supply pipe 14a and the discharge pipe 14b are connected via the multiple relay pipes 14c. The refrigerant flows through these three pipes. The refrigerant flows from the supply pipe 14a to the discharge pipe 14b via the multiple relay pipes 14c.

[0073] The supply pipe 14a and the discharge pipe 14b each extend in the Y direction. The supply pipe 14a and the discharge pipe 14b are spaced apart in the X direction. The relay pipes 14c extend along the X direction from the supply pipe 14a side to the discharge pipe 14b side.

[0074] The relay pipes 14c are arranged in a line with a space therebetween in the Y direction. A gap is defined between two adjacent relay pipes 14c. That is, a plurality of gaps are defined in the cooler 14. In each gap, an A-phase leg 27, a first U-phase leg 21, a second U-phase leg 22, a first V-phase leg 23, a second V-phase leg 24, a first W-phase leg 25, and a second W-phase leg 26 that constitute a semiconductor module are individually provided. That is, the phase legs 21 to 27 are arranged via the relay pipes 14c.

[0075] Furthermore, each of the phase legs 21 to 27 is in contact with the relay pipe 14c in the Y direction. This allows heat generated in each of the phase legs 21 to 27 to be dissipated to the refrigerant via the relay pipe 14c.

[0076] <Capacitor> 3, the first capacitor 51 and the second capacitor 52 are housed in a capacitor case. Specifically, the first capacitor 51 and the second capacitor 52 are resin-sealed in a resin capacitor case. This capacitor case is fixed to a housing 12 (described later) by bolts or the like.

[0077] <Power supply busbar> As described above, the first power supply bus bar 401 and the second power supply bus bar 402 are connected to the first capacitor 51. The first capacitor 51 and the reactor 220 are connected via the first power supply bus bar 401. This first power supply bus bar 401 is divided into a plurality of coupling portions 401a to 401c as shown in FIG.

[0078] That is, the first power supply bus bar 401 is divided into a first connection portion 401a, a second connection portion 401b, and a third connection portion 401c. The first connection portion 401a connects the positive electrode of the battery 500 and one of the two electrodes of the first capacitor 51. The second connection portion 401b connects one of the two electrodes of the first capacitor 51 and the reactor 220. The third connection portion 401c connects the reactor 220 and a midpoint terminal 27a of the A-phase leg 27. The midpoint terminal 27a can also be referred to as a battery terminal.

[0079] A portion of each of the first and second connecting portions 401a and 401b is housed in the capacitor case. The portions of the first and second connecting portions 401a and 401b exposed from the capacitor case extend in the X direction. The third connecting portion 401c extends in both the X and Y directions.

[0080] A second power supply bus bar 402 is connected to the other of the two electrodes of the first capacitor 51. A part of the second power supply bus bar 402 is housed in a capacitor case. The part of the second power supply bus bar 402 exposed from the capacitor case extends in the X direction.

[0081] The ends of the first coupling portion 401a and the second power supply bus bar 402 that are exposed from the capacitor case are provided to the first connector 13a shown in Fig. 3. A wire harness or the like is connected to this first connector 13a. The first power supply bus bar 401 and the second power supply bus bar 402 are electrically connected to the battery 500 via the wire harness.

[0082] The third power supply bus bar 403 is connected to one of the two electrodes of the second capacitor 52. The fourth power supply bus bar 404 is connected to the other of the two electrodes of the second capacitor 52.

[0083] A portion of each of the third power supply bus bar 403 and the fourth power supply bus bar 404 is housed in a capacitor case. The portions of the third power supply bus bar 403 and the fourth power supply bus bar 404 exposed from the capacitor case extend in the X direction. The drain terminals 21b to 27b are connected to the portions of the third power supply bus bar 403 exposed from the capacitor case. The source terminals 21c to 27c are connected to the portions of the fourth power supply bus bar 404 exposed from the capacitor case.

[0084] The portions of the third power supply bus bar 403 and the fourth power supply bus bar 404 exposed from the capacitor case are spaced apart from each other in the Z direction. An insulating member may or may not be interposed between these two power supply bus bars 403, 404.

[0085] <Each phase bus bar> 3, each of the phase bus bars 71-73 is provided to protrude in two directions from the terminal block 180. Each of the phase bus bars 71-73 protrudes toward the second connector 13b side and toward the semiconductor module side from the terminal block 180. One end of each of the phase bus bars 71-73 is provided to the second connector 13b.

[0086] The other end of each of the phase bus bars 71-73 is formed with a connection terminal 81 connected to each of the motor terminals 21a-26a. That is, the connection terminal 81 is the other end of each of the phase bus bars 71-73. The first motor terminal 21a and the second motor terminal 22a are connected to the connection terminal 81 of the U-phase bus bar 71. The third motor terminal 23a and the fourth motor terminal 24a are connected to the connection terminal 81 of the V-phase bus bar 72. The fifth motor terminal 25a and the sixth motor terminal 26a are connected to the connection terminal 81 of the W-phase bus bar 73.

[0087] <Case> 3, the power conversion unit 1 includes the components described above, as well as a housing 12 that supports these components. The housing 12 accommodates a cooler 14, a plurality of semiconductor modules, capacitors 51 and 52, a reactor 220, each of the phase bus bars 71 to 73, and each of the power supply bus bars 401 to 404.

[0088] <Busbar> Here, the bus bar 60 will be described with reference to Fig. 5 and Fig. 6. Note that, here, as an example, the bus bar 60 connecting the first U-phase leg 21 and the second U-phase leg 22 will be described. However, the same applies to the other bus bars 60. Note that in Fig. 5 and Fig. 6, the circuit board 90 is omitted in order to make the configuration of the bus bar 60 easier to understand. In Fig. 6, the housing 12, the circuit board 90, etc. are omitted in order to avoid the drawing becoming complicated.

[0089] The bus bar 60 is mainly made of a conductive material. The bus bar 60 has a plate-shaped main body 60a and legs 60b connected to ends of the main body 60a.

[0090] The main body portion 60a is formed in a bent shape and has a first connecting portion 60a1, a second connecting portion 60a2, a first bent portion 60a3, a second bent portion 60a4, a first extending portion 60a5, a second extending portion 60a6, and a third bent portion 60a7.

[0091] The main body 60a has a symmetrical structure (line symmetry). Therefore, the main body 60a can reduce the assembly reaction force when it is assembled between the suspension leads 21f, 22f. Therefore, the bus bar 60 can be easily assembled without using a jig.

[0092] Moreover, the main body 60a has a function as a spring, for example. That is, the main body 60a forms a spring mechanism. Therefore, when the main body 60a is disposed between the hanging leads 21f, 22f, the connection parts 60a1, 60a2 press the hanging leads 21f, 22f. Therefore, the main body 60a can stand on its own between the hanging leads 21f, 22f. That is, the main body 60a can remain between the hanging leads 21f, 22f without welding, as will be described later.

[0093] However, the present disclosure is not limited thereto. The present disclosure can be used even in the case of a main body portion 60a that does not have a function as a spring. In addition, the present disclosure can be used even in the case of a main body portion 60a that does not have a symmetrical structure.

[0094] The first connection portion 60a1 is a portion to which the first hanging lead 21f is connected. The second connection portion 60a2 is a portion to which the second hanging lead 22f is connected. Each connection portion 60a1, 60a2 is connected to the corresponding hanging lead 21f, 22f by welding or the like. Since the bus bar 60 presses the hanging leads 21f, 22f as described above, it is easy to weld each connection portion 60a1, 60a2 to the hanging leads 21f, 22f.

[0095] The first bent portion 60a3 is a portion that is continuous with the first connecting portion 60a1. The second bent portion 60a4 is a portion that is continuous with the second connecting portion 60a2. The bent portions 60a3 and 60a4 can also be called folded portions.

[0096] The first extension 60a5 is a portion connected to the first bent portion 60a3. The second extension 60a6 is a portion connected to the second bent portion 60a4. The extensions 60a5 and 60a6 are disposed between the connecting portions 60a1 and 60a2 in the Y direction. The third bent portion 60a7 is a portion connected to the first extension 60a5 and the second extension 60a6.

[0097] The extensions 60a5 and 60a6 are longer in the X direction than the connection parts 60a1 and 60a2. Therefore, the third bent part 60a7 protrudes in the X direction more than the connection parts 60a1 and 60a2. It can be said that the extensions 60a5 and 60a6 and the third bent part 60a7 form a convex part in the bus bar 60. It can also be said that the bus bar 60 has a convex part in the center between the connection parts 60a1 and 60a2 in the XY plane. This makes it easier for the bus bar 60 to release the reaction force of the spring by the main body part 60a. Therefore, the bus bar 60 can reduce the pressing force on the suspension leads 21f and 22f. Therefore, the bus bar 60 can relieve the stress on the semiconductor module. It can also be said that the convex part includes at least the third bent part 60a7.

[0098] The foot portion 60b is provided on the first connection portion 60a1 and the second connection portion 60a2. Here, as an example, an example is adopted in which the foot portions 60b are provided at two locations on the first connection portion 60a1 and at two locations on the second connection portion 60a2.

[0099] The foot 60b is provided to protrude from each of the connection portions 60a1, 60a2 toward the connection surface with the hanging leads 21f, 22f. It can also be said that the foot 60b is provided on the bus bar 60 so as to spread outward (Y direction side) with respect to the main body portion 60a. It can also be said that the foot 60b is provided in a direction in which the connection portions 60a1, 60a2 press the hanging leads 21f, 22f.

[0100] The two legs 60b provided on the first connection portion 60a1 are arranged to sandwich the first suspension lead 21f in the arranging direction. That is, the legs 60b are arranged on both sides of the first suspension lead 21f in the arranging direction. Similarly, the two legs 60b provided on the second connection portion 60a2 are arranged to sandwich the second suspension lead 22f in the arranging direction. The legs 60b can also be said to be bifurcated.

[0101] The foot 60b is in contact with the second side surface 21g2 of the insulating resin 21g. The foot 60b can be positioned in the X and Z directions with respect to the suspension leads 21f, 22f before welding. Note that the foot 60b needs to be spaced apart from the signal terminals 21e, 22e to be electrically insulated from them, as shown by the dashed arrows in FIG.

[0102] 5, the foot 60b has an R-bend shape. That is, the foot 60b has a bent shape between the portion in contact with the second side surface 21g2 and the main body 60a. This allows the bus bar 60 to reduce vibration stress. The bus bar 60 is also easily positioned with respect to the suspension leads 21f, 22f.

[0103] The foot 60b does not have to be in contact with the second side surface 21g2. The foot 60b may have a right-angled shape. The present disclosure can also be used in a busbar 60 that does not have the foot 60b. The foot 60b may be provided so as to protrude from each of the connection portions 60a1, 60a2 on the side opposite to the connection surface with the hanging leads 21f, 22f.

[0104] The bus bar 60 is disposed on the cooler 14. More specifically, the bus bar 60 is disposed on the relay pipe 14c of the cooler 14. It can also be said that the bus bar 60 is disposed in the opposing region of the cooler 14. It is preferable that at least a portion of the bus bar 60 is disposed in the opposing region of the cooler 14. This allows the inverter 100 to cool the bus bar 60 by the cooler 14. Furthermore, the bus bar 60 of the inverter 100 is connected to the first suspension lead 21f and the like. Therefore, the inverter 100 can also cool the first U-phase leg 21 and the like via the bus bar 60.

[0105] As a reference example, a busbar in which only the linear portion is arranged in the opposing region of cooler 14 is also considered. However, the busbar 60 has a convex portion arranged in the opposing region of cooler 14. The convex portion has extensions 60a5, 60a6 and a third bent portion 60a7. Therefore, the busbar 60 can have a larger portion arranged in the opposing region of cooler 14 than the configuration of the reference example. Therefore, the inverter 100 can improve the cooling efficiency of the first U-phase leg 21 and the like via the busbar 60.

[0106] Furthermore, a part of the convex portion of the bus bar 60 may be disposed between the insulating resins 21g of the adjacent semiconductor modules. Naturally, the adjacent semiconductor modules indicate semiconductor modules of the same phase. As described above, the relay pipe 14c is disposed between the adjacent semiconductor modules. Therefore, the inverter 100 can improve the cooling efficiency of the first U-phase leg 21 and the like via the bus bar 60.

[0107] Incidentally, the space between the signal terminals 21e and 22e is often a dead space. However, a part of the convex portion of the bus bar 60 is disposed between the signal terminals 21e and 22e. For example, the third bent portion 60a7 of the bus bar 60 is disposed adjacent to the signal terminals 21e and 22e in the Y direction. In this case, the bus bar 60 needs to be spaced apart from the signal terminals 21e and 22e to be electrically insulated from them, as shown by the dashed arrows in FIG. 6. This allows the inverter 100 to provide the bus bar 60 by effectively utilizing a part of the dead space. Therefore, the inverter 100 can prevent the size of the inverter 100 from increasing.

[0108] In the bus bar 60, the distance from the first bent portion 60a3 to the third bent portion 60a7 is equal to the distance from the second bent portion 60a4 to the third bent portion 60a7. This distance is referred to as the first distance. In addition, in the bus bar 60, the distance from the first bent portion 60a3 to the connection portion with the first suspension lead 21f is equal to the distance from the second bent portion 60a4 to the connection portion with the second suspension lead 22f. This distance is referred to as the second distance. In the bus bar 60, the first distance is longer than the second distance. This enables the bus bar 60 to relax the stress that enables the bus bar 60 to maintain its position when assembled between the suspension leads 21f, 22f.

[0109] In this embodiment, the bus bar 60 is used to connect the suspension leads of each phase leg in the same-phase leg group. However, the present disclosure is not limited to this. The bus bar 60 may connect the connection terminals 81 connected to each phase leg in the same-phase leg group. The bus bar 60 may also connect the output terminals of the same-phase legs. For example, the bus bar 60 connects the first motor terminal 21a and the second motor terminal 22a. The first motor terminal 21a and the second motor terminal 22a are larger than the first suspension lead 21f and the second suspension lead 22f. Therefore, less precision is required than when the bus bar 60 is welded to the suspension leads 21f and 22f.

[0110] In this embodiment, the bus bar 60 as described above is adopted. However, the present disclosure is not limited thereto. The bus bar 60 may have a linear body portion, i.e., a body portion having a circular cross section. The bus bar 60 may also have a body portion partially provided with a notch or a recess. Furthermore, the bus bar 60 may be connected to the outside of the suspension leads 21f, 22f. These points are the same for the bus bars 61 to 63 described later.

[0111] <Effects> Here, the effect of the inverter 100 will be described with reference to a reference example. The power conversion device of the reference example (hereinafter, the reference example) has a configuration in which a plurality of high-side switches are connected in parallel, a plurality of low-side switches are connected in parallel, and the bus bar 60 is not provided. In this reference example, fluctuations in the source-to-source voltage Vs may occur. Furthermore, in the reference example, the gate-to-source voltage of the MOSFET fluctuates due to fluctuations in the source-to-source voltage Vs. As a result, in the reference example, the gate voltage of the MOSFET may exceed the rated voltage.

[0112] In contrast, in inverter 100, one upper and lower switches of the same phase leg and the other upper and lower switches are connected in parallel by one or more wires to the wiring connected to motor 600. For example, in inverter 100, the upper and lower switches of first U-phase leg 21 and the upper and lower switches of second U-phase leg 22 are connected in parallel by one or more wires to the wiring connected to motor 600. Also, inverter 100 can be connected in parallel by connecting suspension leads of the same phase legs with bus bar 60.

[0113] Therefore, the inverter 100 can reduce the source-to-source impedance in the common-phase leg. Therefore, the inverter 100 can suppress fluctuations in the source-to-source voltage Vs. The inverter 100 can suppress fluctuations in the gate-to-source voltage of the MOSFET, which is the high-side switch of the common-phase leg. As a result, the inverter 100 can suppress malfunctions in the MOSFET.

[0114] The inverter 100 may also be configured to detect short circuits using a sense MOS. The sense MOS is provided for the high-side switch 31 (MOSFET), for example. The sense MOS may have a drain electrode connected to the gate electrode of the high-side switch 31 and a source electrode connected to the source electrode of the high-side switch 31.

[0115] In this configuration, when the gate-source voltage of the MOSFET fluctuates as in the reference example, the drain-source voltage of the sense MOS also fluctuates. Therefore, in the reference example, there is a possibility that the sense voltage exceeds the short-circuit threshold and a short circuit is erroneously detected. In contrast, the inverter 100 can suppress the fluctuation of the gate-source voltage as described above, and therefore can suppress the short circuit erroneous detection.

[0116] (Variation 1) 7, the present disclosure can also be adopted in a bus bar 61 of Modification 1. Bus bar 61 has a plate-shaped main body 61a and a foot 61b connected to an end of main body 61a.

[0117] The main body 61a has a first connecting portion 61a1, a second connecting portion 61a2, a first bending portion 61a3, a second bending portion 61a4, and a recess 61a5. The main body 61a has an axisymmetric structure. The first connecting portion 61a1 and the second connecting portion 61a2 are similar to the first connecting portion 60a1 and the second connecting portion 60a2. The foot 61b is similar to the foot 60b.

[0118] The first bent portion 61a3 is a portion continuing to the first connecting portion 61a1. The second bent portion 61a4 is a portion continuing to the second connecting portion 61a2. The recess 61a5 is a portion continuing to the first bent portion 61a3 and the second bent portion 61a4. The recess 61a5 is a portion recessed in the X direction with respect to the first bent portion 61a3 and the second bent portion 61a4.

[0119] The first bent portion 61a3 and the second bent portion 61a4 are connected to the first connecting portion 61a1 and the second connecting portion 61a2 in a direction different from that of the above embodiment. Therefore, the first bent portion 61a3, the second bent portion 61a4, and the recessed portion 61a5 are provided at positions away from the signal terminals 21e and 22e. Therefore, the bus bar 61 can easily have an electrical insulation distance from the signal terminals 21e and 22e. The bus bar 61 can be connected in parallel like the bus bar 60, and the source-to-source impedance in the common-mode leg can be reduced.

[0120] (Variation 2) 8, the present disclosure can also be adopted in a bus bar 62 of Modification 2. Bus bar 62 has a plate-shaped main body 62a and a foot 62b connected to an end of main body 62a.

[0121] The main body portion 62a has a first connecting portion 62a1, a second connecting portion 62a2, a first bent portion 62a3, a second bent portion 62a4, and an extension portion 62a5. The main body portion 62a has a point-symmetric structure.

[0122] The first connecting portion 62a1 and the second connecting portion 62a2 are similar to the first connecting portion 60a1 and the second connecting portion 60a2. The first connecting portion 62a1 and the second connecting portion 62a2 each have one foot 62b. The foot portions 62b are provided at one end and the other end of the main body portion 62a.

[0123] The first bent portion 62a3 is a portion connected to the first connecting portion 62a1. The second bent portion 62a4 is a portion connected to the second connecting portion 62a2. The extension portion 62a5 is a portion connected to the first bent portion 62a3 and the second bent portion 62a4. The extension portion 62a5 is a portion connecting the first bent portion 62a3 and the second bent portion 62a4. The main body portion 62a has a Z-shape in a plan view. The busbars 62 can be connected in parallel like the busbars 60, and the source-to-source impedance in the common-phase legs can be reduced.

[0124] (Variation 3) 9, the present disclosure can also be adopted in a bus bar 63 of Modification 3. Bus bar 63 has a plate-shaped main body 63a and a foot 63b connected to an end of main body 63a.

[0125] The main body portion 63a has a first connecting portion 63a1, a second connecting portion 63a2, a first bent portion 63a3, a second bent portion 63a4, and an extension portion 63a5. The main body portion 62a has a point-symmetric structure.

[0126] The first connecting portion 63a1 and the second connecting portion 63a2 are similar to the first connecting portion 60a1 and the second connecting portion 60a2. The first connecting portion 63a1 and the second connecting portion 63a2 each have one foot 63b. The foot portions 63b are provided at one end and the other end of the main body portion 63a.

[0127] The first bent portion 63a3 is a portion continuing to the first connecting portion 63a1. The first bent portion 63a3 is provided by bending from an end portion of the first connecting portion 63a1. The second bent portion 63a4 is a portion continuing to the second connecting portion 63a2. The second bent portion 63a4 is provided by bending from an end portion of the second connecting portion 63a2. In this manner, the bus bar 63 has the bent portions 63a3 and 63a4, which are bent, at adjacent portions of the connecting portions 63a1 and 63a2.

[0128] The extension portion 63a5 is a portion that is continuous with the first bent portion 63a3 and the second bent portion 63a4. The extension portion 63a5 is a portion that connects the first bent portion 63a3 and the second bent portion 63a4. The main body portion 62a has an inverted S-shape in plan view.

[0129] The bus bar 63 can be connected in parallel like the bus bar 60, and the source-to-source impedance in the same phase leg can be reduced. The bus bar 63 has bent portions 63a3 and 63a4 adjacent to the connecting portions 63a1 and 63a2. Therefore, the inverter 100 can reduce the load on the connecting portions 63a1 and 63a2 due to vibration. This is also true for the bus bars 60 and 61.

[0130] In the first to third modified examples, the bus bars 62 to 63 provided in the U-phase leg group have been described. However, the bus bars 62 to 63 are similar in the V-phase leg group and the W-phase leg group. The bus bars 62 to 63 correspond to connection members.

[0131] Although the above describes preferred embodiments of the present disclosure, the present disclosure is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0132] 1...power conversion unit, 100...inverter, 21...first U-phase leg, 21a...first motor terminal, 21b...first drain terminal, 21c...first source terminal, 21f...first suspension lead, 22...second U-phase leg, 22a...second motor terminal, 22b...second drain terminal, 22c...second source terminal, 22f...second suspension lead, 23...first V-phase leg, 23a...third motor terminal, 23b...third drain terminal, 23c...third source terminal, 23f...third suspension lead, 24...second V-phase leg, 24a...fourth motor terminal, 24b...third drain terminal, 24c...fourth source terminal, 24f...fourth suspension lead, 25...first W-phase leg, 25a...fifth motor terminal, 25 b...fifth drain terminal, 25c...fifth source terminal, 25f...fifth suspension lead, 26...second W-phase leg, 26a...sixth motor terminal, 26b...sixth drain terminal, 26c...sixth source terminal, 26f...sixth suspension lead, 31...second high-side switch, 32...second low-side switch, 33...third high-side switch, 34...third low-side switch, 35...fourth high-side switch, 36...fourth low-side switch, 60...bus bar, 60a...main body, 60a1...first connection portion, 60a2...second connection portion, 60a3...first bent portion, 60a4...second bent portion, 60a5...first extension portion, 60a6...second extension portion, 60a7...third bent portion, 60b...foot portion

Claims

[Claim 1] a plurality of semiconductor devices (21 to 26) each having an output terminal (21 a to 26 a) and driven at the same potential; output wiring (71a to 73a) commonly connected between the output terminals of the plurality of semiconductor devices; Each semiconductor device includes a high-side switch (31) and a low-side switch (32) connected in series, and includes an output terminal between the high-side switch and the low-side switch, to which the output wiring is connected; the output wiring is connected between the high-side switch and the low-side switch of each semiconductor device; The output terminals between the high-side switch and the low-side switch of each semiconductor device are connected to each other, and the power conversion device is connected in parallel to the output wiring.

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