JP2015089244A - Inverter device for motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact motor inverter device having an excellent electric characteristic, etc. with the reduction of a weight and an installation area.SOLUTION: A motor inverter device 10 includes two three-phase inverters 13, 13, accommodated in one housing 12 and having power modules 17-19 of each phase composed of the combination of a plurality of switch elements, for driving each motor. A bus bar 14 for applying a DC current to each power module 17-19 in the inverters 13, 13 and a snubber capacitor 15 for suppressing an overvoltage of each switch element are disposed at the center. Each inverter 13, 13 is disposed such that each power module 17-19 is symmetrically positioned on both sides sandwiching the bus bar 14 and the snubber capacitor 15.

Description

  The present invention relates to an inverter device for a motor. For example, in an electric vehicle, an automobile using an auxiliary motor in addition to an engine, etc., two inverters for driving two on-vehicle motors are provided in one casing. It relates to the structure when provided.

FIG. 9 is a basic circuit diagram of one inverter 100 according to a conventional example. Each phase switching element 102 is formed of an IGBT module. Literature relating to the structure of the inverter is mainly for driving one motor 101. Other than that, for example, a technique in which two types of inverters having different actions are mounted in one housing is disclosed (Patent Document 1).
An electric vehicle using an in-wheel motor or a four-wheel drive electric vehicle sometimes uses two or more driving motors, and the same number of inverters as the number of inverters are required to drive these motors.
Also, as a power semiconductor cooling structure, a structure in which a plurality of power semiconductors are arranged side by side in a single case is proposed (Patent Document 2). It is described that the module is capable of driving a motor.

JP 2004-215335 A JP 2013-131666 A

In the case of having two or more motors in a vehicle such as an electric vehicle,
(1) A structure in which two inverters are individually mounted on a vehicle is disadvantageous because the installation area and weight of these inverters increase, so that restrictions on the vehicle design increase and power consumption increases.
(2) As shown in FIG. 10, when two inverters 13 and 13 are arranged in parallel in one housing 12, for example, these inverters 13 and 13 are electrically connected by a bus bar 14 or the like, Compared to the conventional structure in which inverters are individually installed, the size of the two casings can be reduced so that the weight can be reduced and the installation area can be reduced. However, in the configuration in which the two inverters 13 and 13 are simply housed side by side in this way, the overall length of the bus bar 14 connected between the two inverters 13 and 13 is increased, and the inductance component of the bus bar 14 is increased accordingly. Therefore, noise is generated. Since the bus bar 14 is long, it is insufficient in reducing the weight and reducing the size.
(3) In the configuration in which the plurality of power semiconductors are arranged in one case, there is no description regarding wiring connection between the power semiconductors in the case. Since one semiconductor element for driving a motor is made into one package, there is no problem in the wiring length in each package. However, when the power module for each phase in three-phase alternating current is used, the above-mentioned 2 Similarly to the configuration in which two inverters are accommodated side by side, the overall length of the bus bar connected between the two inverters is increased, and the inductance component of the bus bar is increased correspondingly, which may cause noise. When the bus bar becomes longer, it becomes insufficient in reducing the weight and reducing the size.

  An object of the present invention is to provide an inverter device for a motor that can be reduced in size and weight, can reduce the installation area, and is excellent in electrical performance and the like.

The motor inverter device according to the present invention is a motor inverter device that includes two-phase inverters each composed of a power module of each phase in which a plurality of switching elements are combined, and each driving a motor. ,
A bus bar that applies a direct current to each power module of each inverter and a snubber capacitor that suppresses overvoltage of the switching element are arranged in the center, and the inverters are arranged on both sides of the bus bar and the snubber capacitor. The power modules are arranged so as to be symmetrically positioned.

  According to this configuration, when a torque command is given to the motor inverter device, for example, a direct current from the battery is applied to each power module of each inverter via the bus bar and the snubber capacitor. An on / off command is given to a plurality of switching elements in each power module, and thus the motor inverter device converts the direct current into a three-phase alternating current based on the torque command, and drives and controls each motor. By connecting a snubber capacitor to the power module, the overvoltage of the switching element is suppressed.

Since the two inverters are accommodated in one housing, the entire apparatus can be reduced in size and weight can be reduced and the installation area can be reduced as compared with the conventional structure in which the two inverters are individually installed.
In particular, the bus bar and the snubber capacitor are placed in the center, and the inverters are placed on both sides of the bus bar and the snubber capacitor so that each power module is located symmetrically. Therefore, the distance between the snubber capacitor and each power module is minimized. In addition, since the inductance component of the bus bar is minimized, the noise suppression effect is high. Since the bus bar can be shortened, the size can be further reduced and the weight can be reduced accordingly. Further, by arranging the bus bar and the snubber capacitor in a centralized manner, the operation of mounting them can be quickly and easily performed without interfering with other components.

  The motor may be a motor that drives a vehicle. In this case, for example, the host control means of the motor inverter device reads the operation angle based on the accelerator operation by the driver, converts the operation angle into a torque command, and gives this torque command to the motor inverter device. Therefore, each motor can be driven to drive the vehicle.

The snubber capacitor may be shared by the two inverters. In this case, the number of parts, the weight, and the installation area can be reduced as compared with the configuration in which the snubber capacitor is not shared by the two inverters.
The housing may be provided with two water cooling portions for cooling the power modules, respectively, and the snubber capacitor may be provided between the two water cooling portions to cool the snubber capacitor. In this case, water cooling parts for cooling the power module are provided on both sides of the snubber condenser, and the cooling water circulates in these water cooling parts. Circulating cooling water lowers the temperature around the water-cooled part, and can also be expected to cool the snubber condenser.

  The motor inverter device according to the present invention is a motor inverter device that includes two-phase inverters each composed of a power module of each phase in which a plurality of switching elements are combined, and each driving a motor. In addition, a bus bar for applying a direct current to each power module of each inverter and a snubber capacitor for suppressing overvoltage of the switching element are arranged in the center, and each inverter on both sides sandwiching the bus bar and the snubber capacitor, Since the power modules are arranged so as to be symmetrical, it is possible to reduce the size and weight, to reduce the installation area, and to obtain an inverter device for a motor excellent in electrical performance and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram schematically showing a drive unit of a vehicle equipped with a motor inverter device according to a first embodiment of the present invention. It is a top view which shows the structure of the principal part of the inverter apparatus for motors. It is a side view of the inverter apparatus for motors. It is a circuit diagram of the inverter device for the motor. It is a top view which shows the structure of the principal part of the inverter apparatus for motors concerning other embodiment of this invention. It is a side view of the inverter apparatus for motors. It is a circuit diagram of the inverter device for the motor. It is a circuit diagram of the inverter apparatus for motors concerning further another embodiment of this invention. It is a basic circuit diagram of one inverter concerning a conventional example. It is a top view which shows schematically the structure of the conventional inverter apparatus.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram schematically illustrating a drive unit and the like of a vehicle on which the motor inverter device according to the embodiment is mounted. This vehicle is a two-wheel drive electric vehicle in which left and right rear wheels 2 and 2 of a vehicle body 1 are drive wheels and left and right front wheels 3 and 3 are driven wheels. The front wheels 3 and 3 are steering wheels. The vehicle includes motors 4 and 4 that apply driving force to the left and right drive wheels. Each motor 4 is composed of, for example, a three-phase synchronous motor. The rotation of the motor 4 is transmitted to the drive wheels via the speed reducer 5 and the wheel bearing 6. This motor 4 is partly or wholly arranged in the drive wheel, and constitutes an in-wheel motor drive device 7 including the motor 4, the speed reducer 5, and the wheel bearing 6.

  The left and right driven wheels and the left and right drive wheels have brake mechanisms 8 and 8 for driven wheels and brake mechanisms 9 and 9 for drive wheels that apply braking force to the driven wheels and the drive wheels, respectively, by a brake operation by the driver. Is provided. An ECU (also referred to as VCU) 11 that is a high-order control means of the motor inverter device 10 reads an operation angle based on an accelerator operation by a driver, converts the operation angle into a torque command, and converts the torque command to a motor. Command to the inverter device 10. The motor inverter device 10 converts the electric power from the battery Bt mounted on the vehicle into a three-phase alternating current based on the torque command and controls the motors 4 and 4. As a result, the left and right motors 4 and 4 can be driven to drive the vehicle.

  FIG. 2 is a plan view showing the structure of the main part of the motor inverter device 10, and FIG. 3 is a side view of the motor inverter device 10. As shown in FIGS. 2 and 3, the motor inverter device 10 controls the power circuit units 20 and 20 including the housing 12, the three-phase inverters 13 and 13, and the power circuit units 20 and 20. A motor control unit (not shown), a bus bar 14, a snubber capacitor 15, water cooling units 16 and 16, and a smoothing capacitor to be described later. The motor control unit is composed of a computer, a program executed on the computer, and an electronic circuit. The motor control unit converts the current control command into an electric current command according to an acceleration / deceleration command or the like given by an ECU serving as a host control means. A current command is given to the power circuit units 20 and 20. The motor control unit may be housed in the housing 12 or may be provided outside the housing.

  One casing 12 accommodates two three-phase inverters 13 and 13. These two inverters 13 and 13 are composed of power modules 17 to 19 for U, V, and W phases each combining a plurality of switching elements (described later), and drive the motors 4 and 4, respectively. As shown in FIG. 2, in this example, the motor for the right driving wheel is driven by the inverter 13 in the upper half of the figure, and the motor for the left driving wheel is driven by the inverter 13 in the lower half of the figure.

  The bus bar 14 includes a positive power supply bus bar 14 a and a negative power supply bus bar 14 b, and applies a direct current from the battery to the power modules 17 to 19 of the inverters 13 and 13. The snubber capacitor 15 suppresses overvoltage of the switching element. In this example, three snubber capacitors 15 are provided for each of the inverters 13 and 13, and a total of six snubber capacitors 15 are provided for the entire inverter device. Each snubber capacitor is configured in a rectangular parallelepiped shape, for example. In one inverter 13, snubber capacitors 15 are connected in parallel to power modules 17 to 19 for U, V, and W phases.

  The bus bar 14 and the snubber capacitor 15 are arranged in the center of the housing 12. The inverters 13 and 13 are arranged on both sides of the bus bar 14 and the snubber capacitor 15 so that the power modules 17 to 19 are positioned symmetrically. Three snubber capacitors 15 connected to one inverter 13 are arranged at predetermined intervals along a direction parallel to the alignment direction of the power modules 17 to 19 of each phase of the inverter 13, and The power modules 17, 18 and 19 of the U, V and W phases are connected adjacent to each other.

  One snubber capacitor 15 connected to the U-phase power module 17 in one inverter 13 and one snubber capacitor 15 connected to the U-phase power module 17 in the other inverter 13 are adjacent to each other. Located on the left side of the center of the body 12. Snubber capacitors 15 and 15 connected to the V-phase power module 18 are also arranged in the center of the center of the casing 12 adjacent to each other, and the snubber capacitors 15 and 15 connected to the W-phase power module 19 are also connected. They are arranged adjacent to each other on the right side in the center of the housing 12.

  As shown in FIGS. 2 and 3, the power supply bus bar 14 b in the bus bar 14 is installed over the upper surface of each snubber capacitor 15 and is electrically connected to each snubber capacitor 15, and each of the power modules 17 to 19. Electrically connected to the terminal end. The + power supply bus bar 14a is installed on the upper surface of each snubber capacitor 15 via a spacer 23 and is electrically connected to each snubber capacitor 15, and at the terminal ends of each power module 17-19 via the spacer 23. Arranged and electrically connected. By constructing the + power bus bar 14a on each part via the spacer 23, the + power bus bar 14a is disposed above the minus power bus bar 14b. Therefore, the entire bus bar 14 can be concentrated at the center of the housing 12.

  Two water cooling units 16 and 16 for cooling the power modules 17 to 19 are provided on both sides of the housing 12 with the snubber capacitor 15 interposed therebetween. In other words, the snubber capacitor 15 is provided between the two water cooling units 16 and 16. The water cooling unit 16 at each location includes, for example, a flow path 16 a that passes through the inside of the housing and a cooling fin 16 b that is provided near the flow path of the housing 12. The flow paths 16a and 16a of the two water cooling sections 16 and 16 are communicated, and the cooling water can be circulated along the flow paths 16a and 16a by a water cooling section drive source (not shown). Due to the circulating cooling water, the temperature around the water cooling parts 16 and 16 is lowered, and the cooling effect of the snubber condenser 15 can be expected.

FIG. 4 is a circuit diagram of the motor inverter device 10.
Each phase power module 17 to 19 in one inverter 13 includes, for example, two insulated gate bipolar transistors (abbreviation: IGBT), and has a total of six IGBTs per inverter 13. Six IGBTs are normally supplied as IGBT modules housed in a package called 6in1 or 2in1. In this embodiment, for example, a 2-in-1 IGBT module is applied.

  The 6in1 is an IGBT module in which six IGBTs in one inverter 13 and six diodes 24 connected to each IGBT are packaged, and can drive one motor. The 2in1 is, for example, an IGBT module in which two IGBTs in one inverter 13 and two diodes 24 respectively connected to the IGBTs are packaged, and IGBTs of other phases in the inverter 13 The same IGBT module is also used. In this case, three 2-in-1 IGBT modules are used for one motor. IGBT modules other than 6 in 1 or 2 in 1 may be applied.

  Snubber capacitors 15 are connected in parallel to the U, V and W phase power modules 17 to 19 in one inverter 13, respectively. A smoothing capacitor 25 is connected in parallel to the upper stages of the snubber capacitors 15 and 15 respectively connected to the upper stage of the U-phase power module 17 in each inverter 13. In the motor inverter device 10 in which the two inverters 13 and 13 are accommodated in one housing 12, one smoothing capacitor 25 can be shared.

In the configuration in which one smoothing capacitor 25 is shared by the two inverters 13 and 13 as described above, even when the capacitance of the smoothing capacitor 25 is doubled, the smoothing capacitor 25 is not shared, and each inverter 13 is provided with a smoothing capacitor. Rather than weight, cost, and footprint. Even when the two inverters 13 and 13 share one smoothing capacitor 25, it is not always necessary to double the capacity of the smoothing capacitor 25. When the capacity of the smoothing capacitor 25 is less than twice, it is further advantageous in terms of weight, cost, and installation area.
The smoothing capacitor 25 is composed of, for example, an electrolytic capacitor or a film capacitor, and smoothes a relatively low frequency with a large capacity. Therefore, it is also possible to install the smoothing capacitor 25 slightly away from the IGBT.

  In one inverter 13, three film capacitors corresponding to the phase power modules 17 to 19 are used as the snubber capacitor 15, and the snubber capacitor 15 has a smaller capacity and a relatively higher frequency than the smoothing capacitor 25. Since the high frequency characteristic is hindered by the inductance from the capacitor to the IGBT, each snubber capacitor 15 should be installed as close as possible to the IGBT to shorten the wiring length between them.

The effect will be described.
The ECU 11 reads an operation angle based on an accelerator operation by the driver, converts the operation angle into a torque command, and commands the torque command to the motor inverter device 10. When a torque command is given to the motor inverter device 10, a direct current from the battery Bt is applied to each power module 17 to 19 of each inverter 13 via the bus bar 14 and the snubber capacitor 15. An on / off command is given to the plurality of switching elements in each of the power modules 17 to 19, whereby the motor inverter device 10 converts the direct current into a three-phase alternating current based on the torque command, and each of the motors 4, 4. Is controlled. Accordingly, the motors 4 and 4 can be driven to drive the vehicle. By connecting the snubber capacitor 15 to the power modules 17 to 19, overvoltage of the switching element is suppressed.

Since the two inverters 13 are accommodated in one housing 12, the entire apparatus can be reduced in size and weight can be reduced and the installation area can be reduced as compared with the conventional structure in which the two inverters are individually installed. .
In particular, the bus bar 14 and the snubber capacitor 15 are arranged in the center, and the inverters 13 and 13 are arranged on both sides of the bus bar 14 and the snubber capacitor 15 so that the power modules 17 to 19 are positioned symmetrically. Since the distance between the snubber capacitor 15 and each of the power modules 17 to 19 can be minimized and the inductance component of the bus bar 14 is minimized, the noise suppressing effect is high. Since the bus bar 14 can be shortened, the size can be further reduced and the weight can be reduced accordingly. Further, by arranging the bus bar 14 and the snubber capacitor 15 in a centralized manner, the operation of mounting them can be quickly and easily performed without interfering with other components.

Another embodiment will be described.
In the following description, the same reference numerals are given to the portions corresponding to the matters described in the preceding forms in each embodiment, and the overlapping description is omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in advance unless otherwise specified. The same effect is obtained from the same configuration. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  FIG. 5 is a plan view showing the structure of a main part of a motor inverter device 10A according to another embodiment, FIG. 6 is a side view of the motor inverter device 10A, and FIG. It is a circuit diagram of 10A of inverter apparatuses. As shown in FIGS. 5 to 7, the three snubber capacitors 15 may be shared by the two inverters 13 and 13. In other words, if the 6in1 IGBT module has three sets of power input terminals and six 2in1 IGBT modules, the six snubber capacitors 15 used in the first embodiment are omitted. can do.

In this example, one snubber capacitor 15 is connected in parallel to the U-phase power module 17 of the two inverters 13 and 13, and one snubber capacitor 15 is connected in parallel to the two V-phase power modules 18. One snubber capacitor 15 is connected in parallel to one W-phase power module 19.
According to this configuration, the number of parts, the weight, and the installation area can be further reduced as compared with the first embodiment.

  FIG. 8 is a circuit diagram of a motor inverter device 10B according to still another embodiment. When the 6-in-1 IGBT module has one set of power input terminals, one snubber capacitor 15 may be shared by the two inverters 13 and 13. In this case, since the entire inverter device has one snubber capacitor 15, the number of parts, weight, and installation area can be further reduced as compared with the configuration of FIG.

  5-7, it is good also as a structure which arrange | positions the capacitor | condenser which has the function of both a snubber capacitor and a smoothing capacitor instead of a snubber capacitor, and this capacitor is shared by two inverters.

DESCRIPTION OF SYMBOLS 4 ... Motor 10, 10A, 10B ... Motor inverter device 12 ... Housing 13 ... Inverter 14 ... Bus bar 15 ... Snubber capacitor 16 ... Water cooling part 17-19 ... Power module 25 ... Smoothing capacitor

Claims (4)

In an inverter device for a motor, which is composed of a power module of each phase in which a plurality of switching elements are combined, and each of the two three-phase inverters for driving the motor is housed in one housing.
A bus bar that applies a direct current to each power module of each inverter and a snubber capacitor that suppresses overvoltage of the switching element are arranged in the center, and the inverters are arranged on both sides of the bus bar and the snubber capacitor. An inverter device for a motor, characterized in that each power module is arranged symmetrically.   The motor inverter device according to claim 1, wherein the motor is a motor that drives a vehicle.   The motor inverter device according to claim 1 or 2, wherein the snubber capacitor is shared by the two inverters.   4. The motor inverter device according to claim 1, wherein the housing is provided with two water-cooling portions for cooling the power modules, and the space between the two water-cooling portions. An inverter device for a motor, which is provided with the snubber capacitor and cools the snubber capacitor.

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