JP2017041942A - Electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric automobile which allows electric motors for driving wheels to have a parking assist function during parking or stopping of the automobile, as assistance of a parking brake, while using almost no electric power.SOLUTION: An electric automobile comprises electric motors 2, inverters 19, drive control parts 41, gate circuits 20 and a parking brake. A motor restraint control part 42 is provided for making a motor coil of each of U, V, W phases to be short-circuited to restrain the electric motor 2 by turning on all driving elements 21, 22, 23 (24, 25, 26) which are connected to either one of a positive voltage side circuit part 27 and a negative voltage side circuit part 28, in place of control by the drive control part 41, when a parking position is detected by parking position detection means 43.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electric vehicle including an electric motor that rotationally drives a drive wheel, and relates to a technique for providing a parking assist function to the electric motor while using almost no electric power when parking and stopping.

  In the parking mode of an electric vehicle, a parking brake or a parking lock mechanism is usually used without using a wheel driving motor. When the motor function is actively used for parking, it is realized by zero speed control or direct current flowing in a part of the motor (Patent Document 1).

JP 2010-22162 A

  In this case, since power is always consumed in the parking mode, the battery is discharged during long-time parking, which is not practical.

  An object of the present invention is to provide an electric vehicle capable of providing a parking assist function to an electric motor for driving a wheel while using almost no electric power as an assist of a parking brake during parking and stopping.

The electric vehicle according to the present invention includes an electric motor 2 that rotationally drives the drive wheels 1, and
An inverter 19 that converts the DC power of the battery Bt into AC power used to drive the electric motor 2 by turning on and off the plurality of drive elements 21 to 26;
A drive control unit 41 that outputs a motor output command in accordance with a drive command generated by an operation of the accelerator operation unit 15;
A driver circuit 20 that gives on / off commands to the plurality of drive elements 21 to 26 based on a motor output command output by the drive control unit 41;
A parking brake PB that generates a braking force by an operation by an operator when the vehicle is stopped;
With
The drive elements 21 to 26 of the inverter 19 include a plurality of phase circuit units 36 connected in parallel between a positive voltage side circuit unit 27 and a negative voltage side circuit unit 28 connected to the battery Bt. , 37 and 38 are connected in series two by two, and the portions between the two drive elements 21 and 24 (between 22 and 25) and (between 23 and 26) in each phase circuit section 36, 37, 38 are In the electric vehicle connected to the motor coil 2c of each phase of the electric motor 2,
A parking position detecting means 43 for detecting a parking position for generating a braking force in the parking brake PB;
When the parking position is detected by the parking position detecting means 43, it is connected to either the positive voltage side circuit section 27 or the negative voltage side circuit section 28 in the inverter 19 instead of the control by the drive control section 41. A motor restraint controller that restrains the electric motor 2 by short-circuiting the motor coils 2c of each phase of the electric motor 2 by turning on only the drive elements 21, 22, 23 (24, 25, 26). 42 is provided.

  According to this configuration, during normal travel, the drive control unit 41 outputs a motor output command in accordance with the drive command generated by the operation of the accelerator operation unit 15. The driver circuit 20 controls the electric motor 2 by giving on / off commands to the plurality of drive elements 21 to 26 based on the motor output command. Thereby, the driving wheel 1 is rotationally driven. When the electric vehicle is parked or stopped, the parking position detection means 43 detects the parking position when the parking brake PB is operated to generate a braking force. Thereby, instead of the control by the drive control unit 41, the electric motor 2 is restrained by the motor restraint control unit 42.

  This motor restraint control unit 42 turns on only the drive elements 21, 22, 23 (24, 25, 26) connected to either the positive voltage side circuit unit 27 or the negative voltage side circuit unit 28, Each phase motor coil 2c is short-circuited. Therefore, by restraining the electric motor 2, the braking force by the electric motor 2 can be generated. In this way, the electric motor 2 can be used as an auxiliary to the parking brake PB when parking. In this case, only a small amount of power is consumed by the control circuit 40 including a drive control unit that operates the drive elements 21 to 26. When the braking force of the parking brake PB is weak, the electric motor 2 can be used as an auxiliary to the parking brake PB to prevent the vehicle from starting undesirably.

  When the parking position is detected by the parking position detection means 43, the motor restraint control unit 42 may cut off the power supply from the battery Bt to the inverter 19. In this case, since no current flows from the battery Bt to the inverter 19 when the vehicle is parked or stopped, power consumption can be reliably reduced.

  An auxiliary battery Bh that supplies power to the drive control unit 41 may be provided when the motor constraint control unit 42 cuts off power supply to the inverter 19. In this case, since the power is consumed by the drive control unit or the like which is a weak electric circuit portion, only about several W is consumed. The drive control unit and the like can be operated for a long time with a small amount of power from the auxiliary battery Bh.

  When the power supply to the inverter 19 is cut off by the motor restraint control unit 42, switching means Sa for cutting off the power supply from the auxiliary battery Bh to the drive control unit 41 is provided, and the driver circuit 20A In response to a signal for cutting off the power supply from the switching means Sa, all the driving elements 21, 22, 23 (24, 24) connected to either the positive voltage side circuit unit 27 or the negative voltage side circuit unit 28 25, 26) may be turned on. In this case, not only the power supply to the inverter 19 is cut off, but also the power supply from the auxiliary battery Bh to the drive control unit 41 is cut off. That is, only the gate circuit 20A consumes power, and the braking force by the electric motor 2 can be operated for a longer time.

  The electric vehicle according to the present invention includes an electric motor that rotationally drives the driving wheels, an inverter that converts DC power of the battery into AC power used to drive the electric motor by turning on and off a plurality of driving elements, and an operation of an accelerator operation unit. A drive control unit that outputs a motor output command in accordance with the generated drive command, a driver circuit that gives an on / off command to the plurality of drive elements based on the motor output command output from the drive control unit, and a vehicle stop A parking brake that generates a braking force by an operation of the operator at times, and each drive element of the inverter is connected in parallel between a positive voltage side circuit unit and a negative voltage side circuit unit connected to the battery Two each of the plurality of phase circuit units are connected in series, and the portion between the two drive elements in each phase circuit unit is the electric motor. In the electric vehicle connected to the motor coil of each phase, there is provided parking position detecting means for detecting a parking position for generating a braking force in the parking brake. When the parking position is detected by the parking position detecting means, the drive control is performed. In place of the control by the unit, by turning on only the drive elements connected to either the positive voltage side circuit unit or the negative voltage side circuit unit in the inverter, the motor coils of the respective phases of the electric motor A motor restraint control unit for restraining the electric motor by short-circuiting the motor is provided. For this reason, the parking assist function can be provided to the electric motor for driving the wheel while using almost no electric power as an auxiliary to the parking brake when parking and stopping.

1 is a block diagram of a conceptual configuration showing an electric vehicle according to an embodiment of the present invention in a plan view. It is sectional drawing which shows schematically the structure of the in-wheel motor drive device of the same electric vehicle. It is a figure which shows the structural example of the parking brake of the same electric vehicle. It is a block diagram which shows conceptual composition, such as an inverter apparatus of the same electric vehicle. It is a block diagram which shows the detailed structure of the inverter apparatus. It is a flowchart which shows the parking sequence of the same electric vehicle. It is a figure which shows the circuit examples, such as an inverter apparatus of the electric vehicle which concerns on other embodiment of this invention. It is a figure which shows the circuit examples, such as an inverter apparatus of the electric vehicle which concerns on further another embodiment of this invention. It is a block diagram of the conceptual structure which shows the electric vehicle which concerns on further another embodiment of this invention with a top view. It is a block diagram of the conceptual structure which shows the electric vehicle which concerns on further another embodiment of this invention with a top view.

An electric vehicle according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, this electric vehicle has left and right rear wheels 1, 1 at the rear of the vehicle as drive wheels that are individually driven by an electric motor 2, and front wheels 3, 3 are turned by a steering device 4. It is a rear-wheel two-wheel drive vehicle which becomes a driven wheel to be steered. The steering device 4 is operated by a steering operation means 5 such as a steering wheel. Each electric motor 2 for traveling constitutes an in-wheel motor drive device IWM (FIG. 2) described later. Each wheel 1, 3 is provided with a brake SB (service brake) that generates a braking force by operating a brake operation unit 16 such as a brake pedal. Further, the left and right rear wheels 1 and 1 generate a braking force by a parking brake PB (FIG. 3) described later when the electric vehicle is stopped.

  FIG. 2 is a cross-sectional view schematically showing the configuration of the in-wheel motor drive device IWM of this electric vehicle. Each in-wheel motor drive device IWM has the electric motor 2, the reduction gear 6, and the wheel bearing 7, respectively, These are arrange | positioned in part or the whole in a wheel. The rotation of the electric motor 2 is transmitted to the rear wheel 1 which is a drive wheel via the speed reducer 6 and the wheel bearing 7. A brake rotor 8 constituting the brake SB is fixed to a flange portion of the hub wheel 7 a of the wheel bearing 7, and the brake rotor 8 rotates integrally with the rear wheel 1. The electric motor 2 is, for example, an embedded magnet type synchronous motor in which a permanent magnet is built in the core portion of the rotor 2a. The electric motor 2 is a motor in which a radial gap is provided between a stator 2 b fixed to the housing 9 and a rotor 2 a attached to the rotary output shaft 10.

  As shown in FIG. 3, the parking brake PB includes, for example, a side brake lever 31, a side brake wire 32, a link mechanism 35, a brake shoe 34, a brake drum 33, and the like. A link mechanism 35 is connected to the side brake lever 31 via a side brake wire 32, and two brake shoes 34, 34 are configured to be movable inward and outward in the radial direction to the link mechanism 35. The two brake shoes 34 are provided to the brake drum 33 through a radial gap.

  When the driver (operator) operates the side brake lever 31 in the (1) direction when the electric vehicle is stopped, the tension (tension in the (2) direction) is transmitted to the side brake wire 32 connected to the side brake lever 31. Then, the two brake shoes 34, 34 move radially outward (direction (3)) via the link mechanism 35 and come into contact with the brake drum 33. As a result, a braking force is generated. When the side brake lever 31 is released from this state in the direction opposite to the direction (1)), the two brake shoes 34, 34 move radially inward via the side brake wire 32 and the link mechanism 35, and the brake drum Leave 33. Thereby, the brake force is released.

The control system will be described.
As shown in FIG. 1, a control device 14 including an ECU 12 and a plurality (two in this example) of inverter devices 13 is mounted on the vehicle body 11. The ECU 12 is a higher-level control unit that performs overall control of the entire vehicle and gives commands to the inverter devices 13. In the case of an electric vehicle, the ECU 12 is also referred to as a VCU (vehicle control unit). The inverter device 13 gives a driving current to each electric motor 2 for driving driving according to a driving command sent from the ECU 12.

  The ECU 12 and the inverter device 13 are connected so as to be able to transmit signals to each other by a controller area network (abbreviation: CAN) communication or the like. When the electric vehicle is traveling, the ECU 12 reads the operation angle of the accelerator operation unit 15 such as an accelerator pedal. The ECU 12 converts the operation angle into a torque command and commands the inverter device 13 for each electric motor 2.

  The ECU 12 has torque command generation means 12a. The torque command generating means 12a is configured to calculate the left and right rear wheels 1 from the accelerator opening signal output from the accelerator operating section 15, the deceleration command output from the brake operating section 16, and the turning command output from the steering operating means 5. , 1 is generated as a torque command and output to each inverter device 13. The ECU 12 includes a microcomputer, a program executed on the microcomputer, an electronic circuit, and the like.

  FIG. 4 is a block diagram showing a conceptual configuration of an inverter device and the like of this electric vehicle. In FIG. 4, only one electric motor 2 and an inverter device 13 corresponding to the electric motor 2 are illustrated, and other electric motors and inverter devices corresponding to the electric motor are omitted. Each inverter device 13 includes a power circuit unit 17 that is a power conversion circuit unit provided for each electric motor 2, and an arithmetic device 18 that controls the power circuit unit 17. The arithmetic device 18 has a function of outputting information such as each detected value and control value related to the in-wheel motor drive device IWM (FIG. 2) to the ECU 12.

  The power circuit unit 17 includes an inverter 19 that converts DC power of the battery Bt (FIG. 1) into three-phase AC power that is used to drive the electric motor 2, and a gate circuit (driver circuit) 20 that controls the inverter 19. Have. The inverter 19 is composed of a plurality of (six in this example) drive elements 21 to 26 which are semiconductor switching elements, and the three phases (U, V, The drive current of each phase (W phase) is output in a pulse waveform. As the driving elements 21 to 26, for example, semiconductor switching elements such as insulated gate bipolar transistors (abbreviated as IGBT), field effect transistors (abbreviated as FET), and other transistors are applied. .

FIG. 5 is a block diagram showing a detailed configuration of the inverter device.
Each drive element 21 to 26 of the inverter 19 includes three phase circuit units 36, 37, 37 connected in parallel between a positive voltage side circuit unit 27 and a negative voltage side circuit unit 28 connected to the battery Bt. 38 (U, V, W phase circuit section) are connected in series two by two. The portions between the two drive elements 21 and 24 (between 22 and 25) and (between 23 and 26) in each phase circuit section 36, 37, and 38 are motor coils 2c for each phase of the electric motor 2 (FIG. 4). Connected to. A diode (FIG. 4) is connected in parallel to each drive element 21-26. A smoothing capacitor 39 is provided between the positive voltage side circuit unit 27 and the negative voltage side circuit unit 28.

  The gate circuit 20 performs pulse width modulation on the input current command and gives an on / off command to each of the drive elements 21 to 26. The pulse width modulation is performed, for example, so as to obtain a current output driven by a sine wave. The gate circuit 20 that is the weak electric circuit portion of the power circuit portion 17 (FIG. 4) and the arithmetic unit 18 constitute the control circuit 40 that is the weak electric circuit portion in the inverter device 13. The control circuit 40 is constituted by, for example, a computer, a program executed by the computer, and an electronic circuit.

  The arithmetic device 18 includes a drive control unit 41 and a motor constraint control unit 42 described later. The drive control unit 41 outputs three-phase AC voltage command values Vu, Vv, and Vw by a predetermined circuit in accordance with a torque command value given from the torque command generation unit 12a of the ECU 12, which is the host control unit. The power circuit unit 17 (FIG. 4) converts the voltage command values Vu, Vv, Vw output from the drive control unit 41 to output motor drive currents Iu, Iv, Iw.

  For example, when a current is desired to flow from the U phase to the V phase of the electric motor 2, the U-phase driving element 21 (the driving element on the upper left in FIG. 5) connected to the positive voltage side circuit section 27 and the negative voltage side circuit section 28. The switch of the V-phase driving element 25 (the driving element in the lower center of FIG. 5) connected to is turned on, that is, conducted. Then, the current sequentially passes through the U-phase drive element 21 and the U-phase, V-phase, and V-phase drive elements 25 of the electric motor 2 from the positive side of the battery Bt, and flows to the negative side of the battery Bt. When the electric motor 2 is rotated during normal traveling, a current is alternately passed through the U, V, and W phases of the electric motor 2 to generate a rotating magnetic field.

By the way, the method of applying the brake with the electric motor for driving the wheel includes the method of generating the torque in the reversal direction of the electric motor and generating the torque in the direction opposite to the vehicle traveling direction, the method of controlling the rotation speed of the electric motor to zero, the electric motor A method is conceivable in which a direct current is applied to a part of the phase of the phase and no rotating magnetic field is generated.
However, the method of generating torque in the direction opposite to the vehicle traveling direction with the electric motor is effective only when the vehicle is traveling on flat ground, and therefore cannot be applied as an assist for the parking brake during parking. The method of controlling the rotation speed of the electric motor to zero and the method of flowing a direct current through some phases of the electric motor are not effective from the viewpoint of energy utilization efficiency because a large current is always flowed even when the vehicle is parked or stopped. .

  In this embodiment, instead of the control by the drive control unit 41 when the vehicle is parked or stopped, a motor constraint control unit 42 that short-circuits the motor coil 2c (FIG. 4) of the electric motor 2 is provided. When the motor restraint control unit 42 detects that the vehicle is parked or stopped by a parking position detection means 43 described later, only the three drive elements 24, 25, 26 on the negative voltage side (lower side in FIG. 5) are used. All of the three drive elements 21, 22, 23 on the positive voltage side (upper side in FIG. 5) are turned off to short-circuit the motor coil 2c (FIG. 4) of the electric motor 2.

  Thus, by restraining the electric motor 2, a braking force by the electric motor 2 can be generated. The motor restraint control unit 42 turns on all three drive elements 21, 22, and 23 on the positive voltage side (upper side in FIG. 5) and three drive elements 24 on the negative voltage side (lower side in FIG. 5). , 25 and 26 may be turned off to short-circuit the motor coil 2c of the electric motor 2 (FIG. 4). When all the six drive elements 21 to 26 are turned off, there is no power input / output, and the electric motor 2 is in a free state. That is, the electric motor 2 is not restrained.

  The parking position detection means 43 may be, for example, a switch that detects that the driver has operated the side brake lever 31 (FIG. 3) in the direction (1) (FIG. 3) (parking position). It may be a means for detecting that the driver has operated a shift switch (not shown) to the parking position.

  When the parking position detection unit 43 detects the parking position, the motor restraint control unit 42 short-circuits the motor coil 2c (FIG. 4) as described above and cuts off the power supply from the battery Bt to the inverter 19 via the ECU 12. To do. Specifically, switching means 44 is provided for switching the electrical connection between the battery Bt and the inverter 19 so as to be freely opened and closed. As this switching means 44, for example, a relay or the like can be applied. During normal travel, the switching means 44 is closed, and the battery Bt and the inverter 19 are electrically connected. When the motor restraint control unit 42 provides the switching means 44 to the switching means 44 via the ECU 12, the switching means 44 is opened. In this case, since no current flows from the battery Bt to the inverter 19 when the vehicle is parked or stopped, the power consumption can be reliably reduced.

  This electric vehicle is equipped with an auxiliary battery Bh different from the battery Bt. The auxiliary battery Bh supplies power to the control circuit 40 when the motor constraint control unit 42 cuts off the power supply from the battery Bt to the inverter 19. As this auxiliary battery Bh, for example, a battery smaller than a battery generally used in a vehicle, a capacitor, or the like can be applied.

  When the power supply from the battery Bt to the inverter 19 is cut off, only the control circuit 40 including the gate circuit 20 and the arithmetic unit 18 for operating the drive elements 21 to 26 is consumed. The power consumption of only the control circuit 40 is only about several watts. These can be operated for a long time with a small amount of power from the auxiliary battery Bh. In a state where the motor restraint control unit 42 performs control to restrain the electric motor 2, for example, the driver or the like presses the side brake lever 31 (FIG. 3) of the parking brake PB (FIG. 3) in the braking force release direction. Is released, the motor restraint control unit 42 returns to the control by the drive control unit 41 and the switching means 44 is closed. The parking position detection means 43 determines whether or not the side brake lever 31 (FIG. 3) has been released.

  FIG. 6 is a flowchart showing a parking sequence of the electric vehicle. Hereinafter, description will be made with reference to FIGS. 4 and 5 as appropriate. After the start of this process, the parking position detection means 43 detects whether or not the parking position has been operated by a switch or the like when the vehicle is stopped (step S1). If the determination is “No” (step S1: No), the process returns to step S1. If it is determined that the parking position has been operated (step S1: Yes), the motor restraint control unit 42 cuts off the power supply from the battery Bt to the inverter 19 via the ECU 12. That is, the switching means 44 is opened (step S2). Next, the motor restraint control unit 42 turns on all the U, V, and W phase drive elements 24, 25, and 26 on the lower side of FIG. 5 (step S3), and then ends this process.

  According to the electric vehicle described above, when the electric vehicle is parked or stopped, if the parking brake PB is operated to generate a braking force, the parking position detecting means 43 detects the parking position. Thereby, instead of the control by the drive control unit 41, the electric motor 2 is restrained by the motor restraint control unit 42. This motor restraint control unit 42 turns on only the drive elements 21, 22, 23 (24, 25, 26) connected to either the positive voltage side circuit unit 27 or the negative voltage side circuit unit 28, Each phase motor coil 2c is short-circuited. Therefore, by restraining the electric motor 2, the braking force by the electric motor 2 can be generated.

  In this way, the electric motor 2 can be used as an auxiliary to the parking brake PB when parking. In this case, only a small amount of power is consumed by the control circuit 40 including a drive control unit that operates the drive elements 21 to 26. When the braking force of the parking brake PB is weak, the electric motor 2 can be used as an auxiliary to the parking brake PB to prevent the vehicle from starting undesirably. Further, when the parking position is detected by the parking position detection means 43, the motor restraint control unit 42 cuts off the power supply from the battery Bt to the inverter 19. In this case, since no current flows from the battery Bt to the inverter 19 when the vehicle is parked or stopped, power consumption can be reliably reduced.

Another embodiment will be described.
In the following description, the same reference numerals are assigned to the portions corresponding to the matters described in the preceding forms in each embodiment, and overlapping descriptions are 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.

When the computing device 18 becomes unable to perform its function (when the computing device 18 stops), the drive elements 24, 25, and 26 for the U, V, and W phases on the negative voltage side are turned on. If the gate circuit 20 is configured and the power supply to the arithmetic device 18 is cut off, only the gate circuit 20 consumes power. In this case, operation for a longer time is possible. An example of this circuit is shown in FIG.
In the circuit example of FIG. 7, when the power supply from the battery Bt to the inverter 19 is cut off, a key switch Sa (switching means) that cuts off the power supply from the auxiliary battery Bh to the arithmetic unit 18 is provided. . Further, the following gate circuit 20A is provided.

  When the vehicle is turned off by the key switch Sa, the power supply from the auxiliary battery Bh to the gate circuit 20A continues, but the power supply to the arithmetic unit 18 is cut off. As a result, the signal from the arithmetic unit 18 to the gate circuit 20A is interrupted, and all the gates are stopped. However, in the gate circuit 20A, OR circuits 46, 47, 47 connected to the respective driving elements 24, 25, 26 on the lower side of FIG. The gate signal to each of the driving elements 24, 25, and 26 is effective.

As a result, the lower U, V, and W phase drive elements 24, 25, and 26 can all be turned on. Therefore, the motor coils 2c (see FIG. 4) for each phase can be short-circuited. Therefore, by restraining the electric motor 2, the braking force by the electric motor 2 can be generated.
According to the circuit example of FIG. 7, while the braking force is generated by the electric motor 2, only the gate circuit 20 </ b> A is consumed in the control circuit 40, and the braking force by the electric motor 2 can be used for a longer time.

  FIG. 8 shows a single-phase motor control circuit using four drive elements in the inverter. The operating principle of using the electric motor 2 as an auxiliary to the parking brake and the technology for cutting off the power supply to the arithmetic unit 18 are the same as those of the circuit using the above-described three-phase motor.

In each said embodiment, although applied to the electric vehicle of an in-wheel motor drive type, it is not limited to this in-wheel motor drive type.
For example, as shown in FIG. 9, a two-motor on-board transmits driving force from two motors 2 and 2 mounted on the vehicle body to the rear wheels 1 and 1 via a drive shaft DS (constant velocity universal joint and shaft). It is good as a form.
As shown in FIG. 10, a single motor-on-board type may be used in which a driving force is transmitted from one motor 2 mounted on the vehicle body to the rear wheels 1 and 1 via a drive shaft DS.

As the vehicle, a front-wheel drive type electric vehicle that drives the left and right front wheels may be applied in an in-wheel motor drive format, a one-motor on-board format, or a two-motor on-board format. In each of the above types, a four-wheel drive electric vehicle that drives the front, rear, left, and right wheels may be applied.
The in-wheel motor drive unit IWM is a so-called direct motor type in which a cycloid reduction gear, a planetary reduction gear, a parallel biaxial reduction gear, and other reduction gears can be applied. Also good.

  As mentioned above, although the form for implementing this invention based on embodiment was demonstrated, embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 ... Rear wheel (drive wheel)
2 ... Electric motor 2c ... Motor coil 15 ... Accelerator operation unit 19 ... Inverter 20 ... Gate circuit (driver circuit)
21-26 ... drive element 27 ... positive voltage side circuit unit 28 ... negative voltage side circuit unit 41 ... drive control unit 42 ... motor restraint control unit 43 ... parking position detection means Bt ... battery Bh ... auxiliary battery PB ... parking brake

Claims (4)

An electric motor that rotationally drives the drive wheels;
An inverter that converts battery direct current power into alternating current power used to drive the electric motor by turning on and off a plurality of drive elements;
A drive control unit that outputs a motor output command in accordance with a drive command generated by an operation of an accelerator operation unit;
Based on a motor output command output by the drive control unit, a driver circuit that gives on / off commands to the plurality of drive elements;
A parking brake that generates a braking force by an operation by an operator when the vehicle is stopped,
Each of the drive elements of the inverter is connected in series to each of a plurality of phase circuit units connected in parallel between a positive voltage side circuit unit and a negative voltage side circuit unit connected to the battery. In the electric vehicle in which the portion between the two drive elements in each phase circuit unit is connected to the motor coil of each phase of the electric motor,
A parking position detecting means for detecting a parking position for generating a braking force in the parking brake;
When the parking position is detected by the parking position detecting means, all the drive elements connected to either the positive voltage side circuit unit or the negative voltage side circuit unit in the inverter are all replaced with the control by the drive control unit. An electric vehicle comprising: a motor restraint control unit that restrains the electric motor by short-circuiting the motor coil of each phase of the electric motor by turning it on.   The electric vehicle according to claim 1, wherein when the parking position is detected by the parking position detection unit, the motor restraint control unit cuts off power supply from the battery to the inverter.   3. The electric vehicle according to claim 2, further comprising an auxiliary battery that supplies power to the drive control unit when power supply to the inverter is interrupted by the motor restraint control unit. The electric vehicle according to claim 3, wherein when the power supply to the inverter is cut off by the motor restraint control unit, a switching unit that cuts off the power supply from the auxiliary battery to the drive control unit is provided, The driver circuit is an electric vehicle that receives a signal for cutting off the power supply from the switching means and turns on all the drive elements connected to either the positive voltage side circuit unit or the negative voltage side circuit unit.

Images