JP2010063241A - Motor drive system and vehicle equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor drive system which is superior in earthquake resistance, can save space and can reduce cost. <P>SOLUTION: A capacitor device 40 removing a high frequency component of voltage supplied to a motor generator from an inverter is installed to face wide faces of respective phase bus bars arranged in parallel in a terminal stand 70 for connecting a motor cable 30 to the motor generator. The capacitor device 40 comprises a metal plate 78 and a dielectric material 80. The metal plate 78 is arranged so that it faces the wide faces in the same direction of the U-phase bus bar 72, the V-phase bus bar 74 and the W-phase bus bar 76 and it becomes parallel to the bars. The dielectric material 80 is disposed between the respective phase bus bars and the metal plate 78. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric motor drive system and a vehicle including the electric motor drive system, and more particularly to an electric motor drive system including a capacitor that removes a high-frequency component of a voltage supplied from an inverter driving the electric motor to the electric motor and a vehicle including the same.

  Japanese Patent Laying-Open No. 2005-65363 (Patent Document 1) discloses a low-voltage motor that can reduce the voltage sharing between windings against a steep surge voltage and prevent the occurrence of insulation deterioration between windings in a low-voltage motor. Disclose. In this low-voltage motor, after 2n (n is an integer) conductors are wound by half of the number of windings of the motor winding, each of the winding start conductor and the winding end conductor is divided into two, and the winding start N conductors and n conductors at the end of winding are connected. Then, an interwinding distributed capacitance adjusting capacitor is connected to the start of winding, the connection between the start and end of winding of the motor winding, and the end of winding.

According to this low-voltage motor, the voltage sharing between the windings is improved, and the distribution voltage between the windings is relaxed against the steep surge voltage, thereby preventing the occurrence of insulation deterioration between the windings (patent) Reference 1).
JP 2005-65363 A JP-A-2005-73439 JP 2005-185001 A Japanese Examined Patent Publication No. 1-1644

  However, it is difficult to mount a capacitor between the windings in the motor. In addition, the above publication does not specifically disclose the structure of the capacitor, but it needs to have a structure excellent in terms of mounting, such as earthquake resistance, space saving, and cost reduction (easily manufactured). In particular, when a motor system is installed in a vehicle, vehicle vibration is applied in addition to motor vibration, so it is necessary to ensure sufficient earthquake resistance, and there is also a demand for space saving and cost reduction. It will be expensive.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electric motor drive system that is excellent in earthquake resistance and realizes space saving and cost reduction, and a vehicle including the same.

  According to this invention, the electric motor drive system includes an inverter, a power line, and a capacitor device. The inverter drives the electric motor. The power line is disposed between the electric motor and the inverter. A capacitor | condenser apparatus is provided in the terminal block to which a power line is connected, and removes the high frequency component of the voltage supplied to an electric motor from an inverter. And a capacitor | condenser apparatus is comprised by interposing a dielectric material between each phase bus bar arrange | positioned at a terminal block, and a metal member.

  Preferably, the respective phase bus bars are arranged side by side so that the wide surfaces are arranged in the same plane. The metal member has a plate shape and is disposed to face the wide surface of each phase bus bar with a dielectric material interposed therebetween.

  Preferably, each phase bus bar is arranged side by side so that the adjacent bus bar and the wide surface face each other. The metal member has a clearance between each phase bus bar and each phase bus bar, and the first and second opposing portions facing the wide surfaces of the bus bars at both ends of each phase bus bar and not facing the adjacent bus bars. However, it has the connection part which electrically connects the 1st and 2nd opposing part.

  Preferably, the capacitor device is provided on a terminal block for connecting the power line to the electric motor.

  According to the invention, the vehicle includes any one of the above-described electric motor drive systems and drive wheels driven by the electric motor.

  In this invention, the capacitor device for removing the high frequency component of the voltage supplied from the inverter to the electric motor is provided on the terminal block to which the power line is connected. Therefore, the mounting is easy and the capacitor device is disposed. There is no need to secure a separate space in the motor. In addition, since the capacitor device is provided on the terminal block and is configured by interposing a dielectric material between each phase bus bar of the terminal block and the metal member, the structure is strong. Therefore, according to the present invention, it is possible to provide an electric motor drive system that is excellent in earthquake resistance and realizes space saving and cost reduction, and a vehicle including the same.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
1 is a diagram showing a power train configuration of a vehicle equipped with an electric motor drive system according to Embodiment 1 of the present invention. Referring to FIG. 1, vehicle 100 includes a power storage device B, an inverter 10, a motor generator 20, drive wheels 25, a motor cable 30, and a capacitor device 40.

  Power storage device B is connected to positive line MPL and negative line MNL. Inverter 10 includes a U-phase arm 12, a V-phase arm 14, and a W-phase arm 16. U-phase arm 12, V-phase arm 14 and W-phase arm 16 are connected in parallel between positive electrode line MPL and negative electrode line MNL. The U-phase arm 12 includes switching elements Q11 and Q12 connected in series, the V-phase arm 14 includes switching elements Q13 and Q14 connected in series, and the W-phase arm 16 includes switching elements connected in series. It consists of elements Q15 and Q16. Diodes D11-D16 are connected in antiparallel to switching elements Q11-Q16, respectively. As the switching elements Q11 to Q16, for example, an IGBT (Insulated Gate Bipolar Transistor), a power MOSFET (Metal Oxide Semiconductor Field-Effect Transistor), or the like can be used.

  Motor generator 20 is connected to inverter 10 via motor cable 30. Motor cable 30 includes a U-phase cable, a V-phase cable and a W-phase cable connected to U-phase arm 12, V-phase arm 14 and W-phase arm 16, respectively. The capacitor device 40 is connected to the motor cable 30. Capacitor device 40 includes capacitors C1 to C3. One end of the capacitor C1 is connected to the U-phase cable of the motor cable 30, one end of the capacitor C2 is connected to the V-phase cable, and one end of the capacitor C3 is connected to the W-phase cable. The other ends of the capacitors C1 to C3 are connected to each other.

  The power storage device B is a rechargeable DC power source, and includes, for example, a secondary battery such as nickel metal hydride or lithium ion. The power storage device B supplies power to the inverter 10. The power storage device B is charged by receiving regenerative power generated by the motor generator 20 from the inverter 10 during braking of the vehicle.

  The inverter 10 is PWM (Pulse Width Modulation) controlled by a control device (not shown). The switching frequency of switching elements Q11 to Q16 accompanying PWM control is, for example, several kHz to several tens kHz. Inverter 10 converts the DC voltage supplied from power storage device B into a three-phase AC voltage, and outputs the converted three-phase AC voltage to motor generator 20 via motor cable 30. Inverter 10 also receives the kinetic energy of the vehicle from drive wheel 25 when the vehicle is braked, converts the three-phase AC voltage generated by motor generator 20 into a DC voltage, and outputs the DC voltage to power storage device B.

  The motor cable 30 electrically connects the inverter 10 to the motor generator 20. The U-phase cable, V-phase cable, and W-phase cable of the motor cable 30 have inductances LU, LV, and LW, respectively.

  Capacitor device 40 removes a high-frequency component of the voltage supplied from inverter 10 to motor generator 20. Specifically, the capacitor device 40 circulates the high frequency component of the current output from the inverter 10 to the motor cable 30 and prevents the high frequency component of the current from being input to the motor generator 20.

  That is, the PWM-controlled inverter 10 generates a pulse voltage including a high frequency component. When the pulse voltage including the high frequency component is applied to the motor generator 20 as it is, the high frequency component of the current flows through the stray capacitance of the motor generator 20 that has a low impedance with respect to the high frequency component of the current. The voltage is concentrated near the edge. This voltage concentration may cause a breakdown of the motor generator 20.

  Therefore, by providing a capacitor between the phase cables of the motor cable 30, the high-frequency component of the current generated from the inverter 10 is recirculated in the motor cable 30. As a result, the voltage input to the motor generator 20 is a voltage from which the high-frequency component has been removed (a pulse voltage with no rising edge), and in the vicinity of the input end of the motor generator 20 due to the stray capacitance of the motor generator 20. The occurrence of voltage concentration is prevented. The structure of the capacitor device 40 will be described later.

  FIG. 2 is an equivalent circuit diagram of a circuit including inverter 10, motor generator 20, motor cable 30, and capacitor device 40 shown in FIG. 1. Referring to FIG. 2, power supply 50 corresponds to inverter 10, and load 60 corresponds to motor generator 20. The inductance L corresponds to the inductance of the motor cable 30, and the capacitor C corresponds to the capacitor device 40. The resistance R corresponds to the resistance component of the motor cable 30, but its value is small.

  Due to the voltage drop due to the inductance L, the high-frequency component of the current output from the power supply 50 is circulated through the capacitor C. Therefore, the voltage supplied from the power supply 50 to the load 60 is the one from which high frequency components have been removed. That is, the capacitor C removes the high frequency component of the voltage supplied from the power supply 50 to the load 60.

  As described above, in the first embodiment, by using the inductance of the motor cable 30, the high frequency component of the current generated from the inverter 10 due to the PWM control is recirculated by the capacitor device 40. Thereby, the voltage supplied from the inverter 10 to the motor generator 20 is a voltage from which the high frequency component has been removed by the capacitor device 40.

  3 is a plan view for explaining the structure of the capacitor device 40 shown in FIG. 1, and FIG. 4 is a cross-sectional view taken along a section IV-IV shown in FIG. Referring to FIGS. 3 and 4, in the first embodiment, capacitor device 40 is provided on terminal block 70 for connecting motor cable 30 to motor generator 20. Terminal block 70 includes a U-phase bus bar 72, a V-phase bus bar 74, and a W-phase bus bar 76. The U-phase bus bar 72, the V-phase bus bar 74, and the W-phase bus bar 76 are arranged side by side at appropriate intervals so that the wide surfaces are arranged in the same plane.

  The U-phase cable of the motor cable 30 is connected to one end of the U-phase bus bar 72, and the U-phase coil terminal 82 of the motor generator 20 is connected to the other end of the U-phase bus bar 72. Further, the V-phase cable of the motor cable 30 is connected to one end of the V-phase bus bar 74, and the V-phase coil terminal 84 of the motor generator 20 is connected to the other end of the V-phase bus bar 74. Further, the W-phase cable of the motor cable 30 is connected to one end of the W-phase bus bar 76, and the W-phase coil terminal 86 of the motor generator 20 is connected to the other end of the W-phase bus bar 76.

  Capacitor device 40 is arranged to face the wide surfaces of U-phase bus bar 72, V-phase bus bar 74, and W-phase bus bar 76 arranged side by side. Capacitor device 40 includes a metal plate 78 and a dielectric material 80. The metal plate 78 is a conductive member. The dielectric material 80 is a highly dielectric and pressure-resistant member, and is made of, for example, epoxy resin or ceramic. A metal plate 78 is disposed so as to be opposed to and parallel to the wide surfaces in the same direction of the U-phase bus bar 72, the V-phase bus bar 74, and the W-phase bus bar 76, and between each phase bus bar and the metal plate 78. A dielectric material 80 is disposed on the surface. With this configuration, the capacitor C1 shown in FIG. 1 is formed between the U-phase bus bar 72 and the metal plate 78, and the capacitor C2 is formed between the V-phase bus bar 74 and the metal plate 78. Capacitor C 3 is formed between W-phase bus bar 76 and metal plate 78.

  Since the capacitor device 40 having such a structure is formed in a flat plate shape in close contact with the wide surface of each phase bus bar in the terminal block 70, it is structurally strong. In addition, since the structure is simple, manufacturing is easy. Further, the capacitor device 40 is formed using the arrangement space of each phase bus bar in the terminal block 70, which contributes to space saving of the vehicle 100.

  As described above, in the first embodiment, since capacitor device 40 is provided, the high frequency component of the voltage supplied from inverter 10 to motor generator 20 is removed. Thereby, the occurrence of voltage concentration in the vicinity of the input end of motor generator 20 due to the stray capacitance of motor generator 20 is prevented. Therefore, according to the first embodiment, a reduction in insulation of motor generator 20 can be prevented.

  In the first embodiment, the capacitor device 40 is provided on the terminal block 70 that connects the motor cable 30 to the motor generator 20, so that it is easy to mount and a space for disposing the capacitor device 40. There is no need to secure a separate. Further, the capacitor device 40 is provided on the terminal block 70 and is formed in a flat plate shape in close contact with the wide surface of each phase bus bar, so that the structure is strong. Therefore, according to the first embodiment, it is possible to configure a capacitor device that is excellent in earthquake resistance and realizes space saving and cost reduction.

[Embodiment 2]
FIG. 5 is a diagram showing a power train configuration of a vehicle equipped with the electric motor drive system according to the second embodiment. Referring to FIG. 5, vehicle 100 </ b> A includes a capacitor device 40 </ b> A instead of capacitor device 40 in the configuration of vehicle 100 in the first embodiment shown in FIG. 1. Capacitor device 40A includes capacitors C4 to C6. Capacitor C4 is connected between the U-phase cable and V-phase cable of motor cable 30, capacitor C5 is connected between the V-phase cable and W-phase cable, and capacitor C6 is connected to U-phase cable and W-phase cable. Connected between cables.

  Capacitor device 40A also removes the high-frequency component of the voltage supplied from inverter 10 to motor generator 20 in the same manner as capacitor device 40 in the first embodiment. Specifically, capacitor device 40 </ b> A circulates the high frequency component of the current output from inverter 10 to motor cable 30, and prevents the high frequency component of the current from being input to motor generator 20.

  FIG. 6 is a plan view for illustrating the structure of capacitor device 40A in the second embodiment, and FIG. 7 is a cross-sectional view taken along section VII-VII shown in FIG. Referring to FIGS. 6 and 7, capacitor device 40 </ b> A according to the second embodiment is also provided on terminal block 70 </ b> A for connecting motor cable 30 to motor generator 20. In this terminal block 70A, the U-phase bus bar 72, the V-phase bus bar 74, and the W-phase bus bar 76 are arranged in parallel at an appropriate interval so that the adjacent bus bar faces the wide surface.

  Capacitor device 40 </ b> A includes a metal member 88 and a dielectric material 90. The metal member 88 includes a first facing portion that faces a wide surface of the U-phase bus bar 72 that does not face the adjacent V-phase bus bar 74, and a wide and adjacent V-phase of the W-phase bus bar 76. A conductive portion having a second facing portion facing the surface that does not face the bus bar 74 and a connection portion that electrically connects the first and second facing portions while having a clearance between each phase bus bar; It is a sex member. Dielectric material 90 is disposed so as to be filled between each phase bus bar and metal member 88, and is a member having high dielectric properties and pressure resistance, similar to dielectric material 80 in the first embodiment.

  Capacitor device 40A having such a structure is also structurally strong because it is installed on each phase bus bar arranged side by side on terminal block 70A. In addition, since the structure is simple, manufacturing is easy. Further, the capacitor device 40A is also formed by using the arrangement space of each phase bus bar in the terminal block 70A, which contributes to space saving of the vehicle 100A.

  In the above description, the metal member 88 is arranged so as to cover each phase bus bar arranged in parallel from three directions, but the metal member 88 is arranged so as to completely surround each phase bus bar arranged in parallel. May be.

  As described above, also in the second embodiment, by providing capacitor device 40A, the occurrence of voltage concentration near the input end of motor generator 20 due to the stray capacitance of motor generator 20 is prevented. Therefore, also according to the second embodiment, it is possible to prevent the insulation of motor generator 20 from being lowered.

  Also in the second embodiment, since the capacitor device 40A is provided on the terminal block 70A, it is easy to mount and it is not necessary to separately secure a space for disposing the capacitor device 40A. The capacitor device 40A is also provided on the terminal block 70A and is installed on each phase bus bar arranged side by side, so that the structure is strong. Therefore, according to the second embodiment, it is also possible to configure a capacitor device that is excellent in earthquake resistance and realizes space saving and cost reduction.

  In the above embodiment, the capacitor device 40 (40A) is provided on the terminal block 70 (70A) for connecting the motor cable 30 to the motor generator 20, but the motor cable 30 is connected to the inverter 10. If there is a terminal block for connection to the capacitor, a capacitor device may be provided on the terminal block. Note that the capacitor device may be provided only in the terminal block for connecting the motor cable 30 to the inverter 10, but in this case, since the inductance of the motor cable 30 cannot be sufficiently utilized, The reflux effect, that is, the effect of removing the high-frequency component of the voltage is small compared to the first and second embodiments.

  In the above description, the motor generator 20 drives the drive wheels 25. However, for example, in a hybrid vehicle further equipped with an engine as a driving power source, the motor generator 20 uses the power of the engine. It may be a motor generator for generating electricity.

  Further, a boost converter capable of adjusting the inverter input voltage to a predetermined value equal to or higher than the voltage of power storage device B may be provided between power storage device B and inverter 10. As such a boost converter, for example, a known boost chopper circuit can be used.

  In the above, motor generator 20 corresponds to “motor” in the present invention, and motor cable 30 corresponds to “power line” in the present invention.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

It is the figure which showed the power train structure of the vehicle carrying the electric motor drive system by Embodiment 1 of this invention. FIG. 2 is an equivalent circuit diagram of a circuit including an inverter, a motor generator, a motor cable, and a capacitor device shown in FIG. 1. It is a top view for demonstrating the structure of the capacitor | condenser apparatus shown in FIG. It is sectional drawing of the cross section IV-IV shown in FIG. It is the figure which showed the powertrain structure of the vehicle carrying the electric motor drive system by Embodiment 2. FIG. FIG. 11 is a plan view for illustrating the structure of a capacitor device in a second embodiment. It is sectional drawing of the cross section VII-VII shown in FIG.

Explanation of symbols

  10 Inverter, 12 U-phase arm, 14 V-phase arm, 16 W-phase arm, 20 Motor generator, 25 Drive wheel, 30 Motor cable, 40, 40A Capacitor device, 50 Power supply, 60 Load, 72 U-phase busbar, 74 V-phase Bus bar, 76 W phase bus bar, 78 metal plate, 80, 90 dielectric material, 82 U phase coil terminal, 84 V phase coil terminal, 86 W phase coil terminal, 88 metal member, 100, 100A vehicle, B power storage device, MPL positive electrode Wire, MNL negative electrode wire, Q11 to Q16 switching element, D11 to D16 diode, LU, LV, LW, L inductance, C1 to C6, C capacitor, R resistance.

Claims (5)

An inverter that drives an electric motor;
A power line disposed between the electric motor and the inverter;
A capacitor device provided on a terminal block to which the power line is connected, and removing a high frequency component of a voltage supplied from the inverter to the electric motor;
The said capacitor | condenser apparatus is an electric motor drive system comprised by interposing a dielectric material between each phase bus bar arrange | positioned at the said terminal block, and a metal member. The respective phase bus bars are arranged side by side so that the wide surfaces are arranged in the same plane,
2. The electric motor drive system according to claim 1, wherein the metal member has a plate shape and is disposed to face a wide surface of each phase bus bar with the dielectric material interposed therebetween. Each phase bus bar is arranged side by side so that the adjacent bus bar and the wide surface face each other
The metal member is
A first and a second facing portion facing a wide surface of the bus bars at both ends of each phase bus bar and facing a surface not facing an adjacent bus bar;
2. The electric motor drive system according to claim 1, further comprising a connection portion that electrically connects the first and second opposing portions with a clearance between each phase bus bar.   The electric motor drive system according to any one of claims 1 to 3, wherein the capacitor device is provided on a terminal block for connecting the power line to the electric motor. The motor drive system according to any one of claims 1 to 4,
A vehicle comprising drive wheels driven by the electric motor.

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