JP5797983B2 - Electric vehicle capacitor discharge device - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle capacitor charge discharging apparatus for discharging electric charges of a smoothing capacitor in an in-hole motor type electric vehicle when the power is turned off.

  In an electric vehicle that receives power supply from a storage battery and drives a motor with an inverter, a smoothing capacitor is provided in parallel with the inverter. The electric charge stored in the smoothing capacitor is stored without being discharged immediately even when the main power switch is turned off. This stored charge is not preferable for safety and is preferably discharged.

  As a method for discharging the smoothing capacitor, a method is proposed in which a current is passed through the motor coil and the electric charge of the smoothing capacitor is consumed by the motor coil (for example, Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 7-7807 JP 2009-27831 A

  In an in-wheel motor type electric vehicle, when the main power is turned off, simply passing a current through the motor coil and consuming the electric charge of the smoothing capacitor in the motor coil causes the vehicle to move slightly, giving the passenger a sense of abnormality. There is a case.

  An object of the present invention is that in an in-wheel motor type electric vehicle, when the main power is turned off, the electric charge of the smoothing capacitor can be consumed and discharged by the motor coil without causing the vehicle to move, and safety is ensured. It is an object of the present invention to provide a capacitor charge discharge device for an electric vehicle that can improve the efficiency.

The electric vehicle capacitor charge discharge device of the present invention has two or more drive wheels 2 driven by independent in -wheel type motors 6, and a storage battery 19 as a power supply system for driving each motor 6, A plurality of inverters 31 that are supplied with electric power from the storage battery 19 to drive the motors 6, a smoothing capacitor 33 a connected in parallel to the inverters 31, and an open / close command according to the operation of the power supply operating means 18. a switching command means 39, in response to switching command from the inverter 31 and the switching command means 39 provided on the battery 19 side of the parallel circuit of the capacitor 33a to open and close the flow of current between battery 19 and the inverter 31 In an electric vehicle having a main power switch 38,
When an off signal for turning off the main power switch 38 is received from the opening / closing command means 39, the torque in the reverse rotation direction is applied to the left and right wheels or the front and rear wheels as the driving wheels by the electric charge stored in the capacitor 33a. A mutual reverse rotation discharge control means 40 for controlling the flow of current to the coils of the motors 6 is provided so as to occur.
In this specification, the “in-wheel type motor” means that the motor 6 does not necessarily have to be provided in the wheel, and a part of the in-wheel motor device 8 that is an assembly part integrated with the motor 6. Is provided in the wheel 2.

According to this configuration, when the main power switch 38 is turned off, the motor 6 is controlled such that torque in the reverse rotation direction is generated in the left and right wheels or the front and rear wheels as drive wheels by the control of the mutual reverse rotation discharge control means 40. Current flows through the coil. As a result, the electric charge of the smoothing capacitor 33a is consumed by the coil of the motor 6 and discharged. Torque is generated by the current of the motor coil for this discharge, but the direction of torque is opposite between the left and right wheels or between the front and rear wheels, and the charge of the smoothing capacitor 33a is slight. Due to the inertia of the vehicle and the static frictional resistance between the tire and the road surface, the vehicle will not move.
In this way, even though it is an in-wheel motor type electric vehicle, when the main power is turned off, the electric charge of the smoothing capacitor 33a can be consumed and discharged by the motor coil without causing any movement of the vehicle, which is safe. It is possible to improve the performance. Further, since the electric charge is consumed by the motor coil, it is not necessary to provide a resistor for consuming electric charge, and a safe discharge can be realized only by control without increasing the number of high electric components.

  In the present invention, each of the motors 6 includes a motor 6, a wheel bearing 4 that supports the driving wheel, and a speed reducer 7 that decelerates the rotation of the motor 6 and transmits it to the rotating side wheel of the wheel bearing 4. The in-wheel motor apparatus 8 which consists of these may be comprised. In the in-wheel motor device 8 provided with the speed reducer 7, even a slight torque of the motor 6 leads to the movement of the vehicle, but the direction of the torque is reversed between the left and right wheels or between the front and rear wheels as described above. Thus, the smoothing capacitor 33a can be discharged by consuming electric charge with the motor coil without causing movement of the vehicle.

In this invention, when the mutual reverse rotation discharge control means 40 receives an off signal for turning off the main power switch 38 from the open / close command means 39, the output voltage of the inverter 31 is less than a set discharge voltage threshold value or The operation of the inverter 31 may be started until the value becomes equal to or less than the threshold value, and the operation of the inverter 31 may be stopped when the value becomes less than or less than the threshold value.
By starting the operation of the inverter 31 after the main power switch 38 is turned off, the electric charge can be consumed by the coil of the motor 6. Further, by comparing the output voltage of the inverter 31 with the threshold value and stopping the operation of the inverter 31, it can be confirmed that the necessary discharge has been performed, and the inverter 31 can be brought into a current interruption state. Thereby, after the necessary discharge, the motor 6 can be stopped completely and the safety can be improved.

  In the present invention, in the case of two-wheel drive, the drive wheels on which the motor 6 is installed may be left and right front wheels or left and right rear wheels. In that case, by causing a current to flow in the motor coil so that torque in the reverse rotation direction is generated in the left and right wheels, the vehicle can be discharged without causing movement.

  Four-wheel drive, that is, drive wheels on which motors are installed may be left and right front wheels and left and right rear wheels. In that case, it is possible to cause the vehicle to discharge without causing movement by causing currents to flow in the front and rear wheels so that torques in the opposite rotation directions are generated. The direction of rotation for generating torque may be the direction in which the front and rear wheels approach each other or the direction in which they move away from each other.

The capacitor charge discharge device for an electric vehicle according to the present invention has two or more drive wheels driven by independent in -wheel type motors, a storage battery as a power supply system for driving each motor, and electric power from the storage battery. A plurality of inverters that are supplied to drive each of the motors, a smoothing capacitor connected in parallel to the inverters, an open / close command unit that issues an open / close command in accordance with an operation of a power supply operation unit, and in an electric vehicle having a main power switch than parallel circuit portion provided on the battery side in response to switching command from the switching command means for opening and closing the flow of current between the battery and the inverter, the mains from said switching command means When an off signal for turning off the switch is received, the electric charge stored in the capacitor causes the drive wheel to In the in-wheel motor type electric vehicle, the left and right wheels or the front and rear wheels are provided with mutual reverse rotation discharge control means for controlling the flow of current to the coils of the motors so that torque in the reverse rotation direction is generated. When the main power is turned off, the electric charge of the smoothing capacitor can be consumed and discharged by the motor coil without causing movement of the vehicle, and safety can be improved.

It is a top view which shows the conceptual structure of the vehicle provided with the capacitor | condenser charge discharge apparatus of the electric vehicle which concerns on one Embodiment of this invention. It is a circuit diagram of the inverter device. It is a flowchart which shows control of the mutual reverse rotation discharge control means of the capacitor | condenser charge discharge apparatus. It is explanatory drawing which shows the torque generation direction of each drive wheel by the mutual reverse rotation discharge control means in a two-wheel drive vehicle. It is explanatory drawing which shows the torque generation direction of each drive wheel by the mutual reverse rotation discharge control means in a four-wheel drive vehicle.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view showing a conceptual configuration of an electric vehicle equipped with the capacitor charge discharging device of this embodiment. This electric vehicle is a four-wheeled vehicle in which the wheels 2 that are the left and right rear wheels of the vehicle body 1 are drive wheels and the wheels 3 that are the left and right front wheels are driven wheels. The front wheel 3 is a steering wheel. The left and right wheels 2, 2 serving as driving wheels are driven by independent in-wheel motors 6. The rotation of the motor 6 is transmitted to the wheel 2 via the reduction gear 7 and the rotation side wheel of the wheel bearing 4. The motor 6, the speed reducer 7, and the wheel bearing 4 constitute an in-wheel motor device 8 that is an assembly part. The reducer 7 is, for example, a cycloid type reducer and has a high reduction ratio of 10 or more. In the in-wheel motor device 8, the motor 6 is installed close to the wheel 2, and a part or the whole of the in-wheel motor device 8 is disposed in the wheel 2. The storage battery 19 is used as a drive for the motor 6 and as a power source for the electrical system of the entire vehicle.

  The control system will be described. A general control unit 21 that is a main ECU (electrical control unit) that performs overall control of the entire vehicle, and a plurality of (two in the illustrated example) that control each driving motor 6 in accordance with instructions from the general control unit 21. ) Inverter device 22 is mounted on the vehicle body 1. The overall control unit 21 and the inverter device 22 constitute a motor drive device 20. The overall control unit 21 includes a computer, a program executed by the computer, various electronic circuits, and the like. The overall control unit 21 and the weak electric system of each inverter device 22 may be configured by a common computer or an electronic circuit on a common substrate.

  The overall control unit 21 includes a torque distribution unit 48, and the torque distribution unit 48 outputs an accelerator opening signal output from the accelerator operation unit 16, a deceleration command output from the brake operation unit 17, and a steering unit 15. Are generated as torque command values and output to each inverter device 22. The accelerator operation unit 16 and the brake operation unit 17 are each composed of a pedal such as an accelerator pedal and a brake pedal, and a sensor that detects an operation amount of the pedal. The steering means 15 includes a steering wheel and a sensor that detects a rotation angle thereof. In addition to the above control, the overall control unit 21 controls each part of the vehicle based on signals from various sensors such as a vehicle speed sensor, a load sensor, and a wheel rotation sensor (all not shown) provided in the vehicle. The function to perform.

  The inverter device 22 includes a power circuit unit 28 that is a power conversion circuit unit provided for each motor 6 and a motor control unit 29 that controls the power circuit unit 28. The motor control unit 29 has a function of outputting information such as detection values and control values regarding the in-wheel motor device 8 included in the motor control unit 29 to the overall control unit 21. The power circuit unit 28 includes an inverter 31 that converts the DC power of the storage battery 19 into three-phase AC power that is used to drive the motor 6, and a PWM driver 32 that is a means for controlling the inverter 31.

  In FIG. 2, the motor 6 comprises a three-phase synchronous motor, for example, an IPM type (embedded magnet type) synchronous motor. The inverter 31 includes a plurality of drive elements 31a that are semiconductor switching elements, and outputs a drive current of each phase of the three phases (U, V, W phase) of the motor 6 in a pulse waveform. The PWM driver 32 performs pulse width modulation on the input current command and gives an on / off command to each of the drive elements 31a. The pulse width modulation is performed, for example, so as to obtain a current output driven by a sine wave. The PWM driver 32 which is a weak electric circuit part of the power circuit part 28 and the motor control unit 29 constitute an arithmetic unit 33 which is a weak electric circuit part in the inverter device 22. The calculation unit 33 includes a computer, a program executed on the computer, and an electronic circuit. The calculation unit 33 controls the motor current by vector control or the like using the detection value of the angle detector 36 that detects the rotation angle of the motor 6.

  In addition to this, the inverter device 22 is provided with a smoothing portion 33 by a smoothing capacitor 33 a interposed in parallel between the storage battery 19 and the inverter 31. The smoothing unit 33 may be provided with a capacitor 33a.

The main power switch 38 is a switch for switching supply / interruption of electric power from the storage battery 19 to each inverter device 22 and electric devices in each part of the vehicle. The main power switch 38 comprises an electromagnetic contactor or the like, and is opened and closed in response to an opening / closing command from the opening / closing command means 39 as shown in FIG. The open / close command means 39 is a means for giving an open / close command to the main power switch 38 in accordance with the operation of the power supply operation means 18. The power supply operating means 18 may be a key switch or a button switch. The opening / closing command means 39 is provided in the overall control section 21 in the illustrated example, but may be provided separately from the overall control section 21, for example, may be integrated with the power supply operation means 18.

  In this embodiment, the mutual reverse rotation discharge control means 40 having the following functions is provided in the electric vehicle configured as described above. When the mutual reverse rotation discharge control means 40 receives an off signal for turning off the main power switch 38 from the open / close command means 39, the back side of the driving wheel is driven by the electric charge stored in the smoothing capacitor 33a. This is a means for controlling current to flow to the coils of the stators of the motors 6 and 6 so that the left and right wheels 2 and 2 generate torques in the directions opposite to each other. That is, a current is passed through the coils of the motors 6 and 6 so as to rotate one of the left and right wheels 2 to the forward side and the other wheel 2 to the reverse side. The mutual reverse rotation discharge control means 40 is provided in the overall control unit 21, for example, but may be provided in the inverter device 22.

  Specifically, the mutual reverse rotation discharge control means 40 performs the control shown in the flowchart in FIG. When the main power supply off signal is received (step S1), the operation of the inverter 31 is started (S2). The operation of the inverter 31 is started so that current flows through the coils of the motors 6 and 6 so that torques in the opposite rotation directions are generated in the left and right wheels 2 and 2. For example, as shown by arrows A and B, when the right wheel 2 receives the torque in the backward direction and the left wheel 2 receives the forward torque, the inverter 31 driving the right wheel 2 The operation of the inverter is started so that a rotating magnetic field in the backward direction with a predetermined extremely low speed is generated in the coil. In the inverter 31 that drives the left wheel 2, the operation of the inverter is started so that a rotating magnetic field in the forward direction at a very low speed is generated in the coil of the motor 6. It should be noted that which of the left and right wheels 2 and 2 is set in the reverse direction and the rotational advance speed of the rotating magnetic field is set in the mutual reverse rotation discharge control means 40 as appropriate.

  In this way, a current is passed through the coil of the motor 6 to discharge the electric charge of the capacitor 33a. During this time, the inverter voltage VINV which is the output of the inverter 31 is compared with the set discharge voltage threshold VTHR (S3), and the inverter voltage VINV Becomes less than the discharge voltage threshold VTHR, the operation of the inverter 31 is stopped (S4).

According to this capacitor charge discharging apparatus, when an OFF command of the main power switch 38 is output by the opening / closing command means 39 by operating the power supply means 18 or the like, the main power switch 38 turns the main power switch 38 in response to this command. Turn off. At this time, the turn-off command from the open / close command means 39 is also given to the mutual reverse rotation discharge control means 40, and controlled by the mutual reverse rotation discharge control means 40 to the rear left and right wheels 2, 2 as drive wheels. An electric current is passed through the coils of the motors 6 of the wheels 2 and 2 so that torques in the opposite rotation directions are generated. As a result, the electric charge of the smoothing capacitor 33a is consumed by the coil of the motor 6 and discharged. Torque is generated by the current of the motor coil for this discharge, but the directions of the torques of the left and right wheels 2 and 2 are opposite to each other, and the electric charge of the smoothing capacitor 33a is slight. Due to inertia and static frictional resistance between the tire and the road surface, the vehicle will not move. In the in-wheel motor device 8 provided with the speed reducer 7, even a slight torque of the motor 6 leads to the movement of the vehicle, but as described above, the directions of the torques are reversed between the left and right wheels 2, 2. Without causing the vehicle to move, electric charge is consumed by the motor coil, and the smoothing capacitor can be discharged.

  As described above, even though the electric vehicle is an in-wheel motor type, when the main power switch 38 is turned off, the electric charge of the smoothing capacitor 33a can be consumed by the motor coil and discharged without causing the vehicle to move. It is possible to improve safety. Further, since the electric charge is consumed by the motor coil, it is not necessary to provide a resistor for consuming electric charge, and a safe discharge can be realized only by control without increasing the number of high electric components.

  During the above discharge, the inverter voltage VINV is monitored, and when the inverter voltage VINV falls below the discharge voltage threshold VTHR, the operation of the inverter 31 is stopped. Can be improved.

In addition, although the said embodiment demonstrated about the case where a vehicle is a two-wheel drive and a rear-wheel drive, this invention is applicable also when it is a two-wheel drive and is a front-wheel drive. In the case of front wheel drive, when the capacitor 33a is discharged after the main power supply is cut off, for example, as shown in FIG. In addition, the control of flowing current to the coils of each motor is performed by the mutual reverse rotation discharge control means.
In the case of four-wheel drive, when the capacitor 33a is discharged after the main power supply is cut off, for example, as shown in FIG. 5 (A) or (B), the front wheel 3 and the rear side in the same direction on the left and right. The mutual reverse rotation discharge control means controls the current to flow to the coils of the motors so that torques in the opposite rotation directions are generated in the wheels 2.
4 and 5, the arrows indicate the traveling direction due to the application of torque to the wheels 2 and 3.

DESCRIPTION OF SYMBOLS 1 ... Vehicle body 2, 3 ... Wheel 4 ... Wheel bearing 6 ... Motor 7 ... Reducer 8 ... In-wheel motor device 18 ... Power supply operation means 19 ... Storage battery 21 ... General control part 22 ... Inverter device 31 ... Inverter 33a ... For smoothing Capacitor 38 ... main power switch 39 ... open / close command means 40 ... mutual reverse rotation discharge control means

Claims (6)

Two or more drive wheels driven by independent in -wheel type motors, and as a power supply system for driving the motors, a storage battery and a plurality of power supplies from the storage battery to drive the motors. inverter and a capacitor for smoothing connected in parallel with the inverter, a switching command means for issuing a switching command in response to the operation of power operation means, provided on the battery side of the parallel circuit of the inverter and a capacitor wherein the opening and closing In an electric vehicle having a main power switch that opens and closes the flow of current between the storage battery and the inverter in response to an opening / closing command from the command means,
When an off signal for turning off the main power switch is received from the opening / closing command means, torque in the reverse rotation direction is generated in the left and right wheels or the front and rear wheels, which are the driving wheels, due to the electric charge stored in the capacitor. A capacitor charge discharging device for an electric vehicle, comprising a mutual reverse rotation discharging control means for controlling a current to flow to the coils of the motors.   2. The in-wheel according to claim 1, wherein each of the motors includes the motor, a wheel bearing that supports the driving wheel, and a speed reducer that decelerates the rotation of the motor and transmits the rotation to the rotating side wheel of the wheel bearing. A capacitor charge discharging device for an electric vehicle constituting a motor device.   In Claim 1 or Claim 2, when the mutual reverse rotation discharge control means receives an off signal for turning off the main power supply from the open / close command means, the output voltage of the inverter is less than a set discharge voltage threshold value or An electric vehicle capacitor charge discharging device that starts operation of an inverter until it becomes equal to or less than a threshold value, and stops operation of the inverter when less than or less than the threshold value.   4. The capacitor charge discharging apparatus for an electric vehicle according to claim 1, wherein the drive wheels on which the motor is installed are left and right rear wheels. 5.   4. The capacitor charge discharging apparatus for an electric vehicle according to claim 1, wherein the drive wheels on which the motor is installed are left and right front wheels. 5.   4. The capacitor charge discharging apparatus for an electric vehicle according to claim 1, wherein the driving wheels on which the motor is installed are left and right front wheels and left and right rear wheels. 5.

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