JPH03251002A - Motor controller for electric car - Google Patents

Abstract

PURPOSE:To prevent consumption of battery by a method wherein the control section of a car interrupts exciting current supply from an inverter to a motor when the rotational speed sensor in a car senses zero speed for longer than a predetermined time during operation and a brake switch detects turn ON of brake. CONSTITUTION:A motor controller 18 on a car body 16 feeds output from a secondary battery 20 to an inverter 22 which produced VVVF power for rotting a motor 24, the rotational speed thereof is then detected through a rotation sensor 26. Controller 28 for the inverter 22 is connected with the rotation sensor 26, the inverter 22, an accelerator opening sensor 30, a brake switch 34 to be operated through a brake pedal 32, and a timer 36. If the rotation sensor 26 indicates zero during operation of an electric car 10, the timer 36 is actuated and when turn ON of the brake switch 34 is detected upon elapse of a predetermined time, a controller 28 interrupts exciting current supply from the inverter 22 to the motor 24.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention includes a battery that charges and discharges electric power, an inverter that converts direct current supplied from the battery into alternating current, and an inverter that uses the alternating current converted by the inverter. The present invention relates to a motor control device for an electric vehicle that includes a motor that drives drive wheels.

[Background Art] Recently, electric vehicles have been studied as pollution-free vehicles that do not produce harmful exhaust gases, and some of them have already been put into practical use.

DC motors, which are easy to control, were used as the drive source for early electric vehicles, but DC motors have brushes and other parts that are difficult to maintain, so recently induction motors, which are easy to maintain, have been used. It has become.

The motors used in electric vehicles are torque-controlled, unlike normal industrial motors. In order to perform the necessary torque control and stabilize the vehicle's maneuverability, the induction motor is controlled by vector control or slip frequency control. In order to improve the response during starting, the excitation current is supplied to the motor even when the motor is stopped.

On the other hand, as a known technique, as shown in Japanese Unexamined Patent Publication No. 57-130839, there is a technique in which the brake lamp does not light up when the parking brake is operated.

Further, as a known technique, as shown in Japanese Patent Application Laid-Open No. 63-71445, there is a technique in which the brake lamp current is changed depending on the amount of depression of the brake.

[Problem to be solved by the invention] When starting a conventional electric vehicle, the motor control device
Although it takes time to switch from the brake pedal to the accelerator pedal, and there is sufficient time for the excitation current to rise at data start, the excitation current continues to flow to the motor even when the motor is stopped, so the battery is This has the problem of consuming power and causing an unnecessary temperature rise in the control element.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a motor control device for an electric vehicle that prevents battery consumption by stopping excitation current when the vehicle is stopped.

[Means for Solving the Problems] A motor control device for an electric vehicle according to the present invention includes a battery that charges and discharges electric power, an inverter that converts direct current supplied from the battery into alternating current, and A motor that drives a drive wheel with an alternating current, a rotation speed sensor that detects the rotation speed of the motor, a brake switch that detects ON/OFF of a brake that brakes a vehicle, and a rotation sensor and a detection signal of the brake switch. and a control section for input. Therefore,
When the control unit detects that the rotation speed of the motor is zero for a predetermined time or more based on the signal from the rotation speed sensor and the brake is in the ON state based on the signal from the brake switch when the vehicle is in a running state, The feature is that the inverter is controlled to stop the excitation current to the motor.

[Function] The electric vehicle motor control device of the present invention converts direct current supplied from a battery into alternating current using an inverter, drives a motor with the converted alternating current, and rotates drive wheels with the motor. The rotation speed of the motor is detected by a rotation speed sensor, the ON/OFF state of the brake that brakes the vehicle is detected by a brake switch, and the detection signals from the rotation sensor and brake switch are input to the control unit, and the vehicle is in a running state. In this case, if it is detected that the rotation speed of the motor is zero for a predetermined time or longer based on the signal from the rotation speed sensor and that the braking brake is in the ON state based on the signal from the brake switch, the control section controls the excitation current to the motor. Control the inverter to stop.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 2, the electric vehicle 10 has a vehicle body 16 supported by front wheels 12 and rear wheels 14, and a motor control device 18 is mounted on the vehicle body 16.

As shown in detail in FIG. 1, the motor control device 18 has a battery 20 that charges and discharges power.
An inverter 22 is connected to convert direct current supplied from the battery into alternating current.

A motor 24 that drives the front wheels 12 as drive wheels using the converted alternating current is connected to the inverter 22, and the motor 24 is provided with a rotation speed sensor 26 that detects the motor rotation speed.

Further, the rotation speed sensor 26 is connected to a controller 28 that controls the inverter 22, and the controller 28 includes the inverter 22, an accelerator sensor 30 that detects the opening degree of the accelerator. Turn on/off by operating the brake pedal 32.
A brake switch 34 that is turned off and a timer 36 are connected.

Further, a brake lamp 40 is connected to the battery 20 via a switch 38, and the switch 38 is turned on and off in conjunction with the brake switch 34.

Next, the operation of this embodiment will be explained along the flowchart of FIG.

When the electric vehicle 10 is in a running state, the controller 28
controls the driving of the inverter 22 based on the signals from the rotation speed sensor 26 and the accelerator sensor 30 (Step
).

Then, the controller 28 determines whether the motor rotation speed has become zero based on the signal from the rotation speed sensor 26, that is, whether the electric vehicle 10 has stopped (5tep 2).
When it is determined that the motor rotation speed has become zero, the timer 36
(Step 3).

Then, the controller 28 determines whether the motor rotation speed remains zero based on the signal from the rotation speed sensor 26.
step 4), if it is determined that the motor rotation speed remains zero, it is determined whether the timer 36 has elapsed for 1 second (step 4).
ep5).

Further, when the controller 28 determines that the timer 36 has elapsed for 1 second, the controller 28 determines whether the brake switch 34 is in the ON state (5tep 6), and determines whether the brake switch 34 is in the ON state.
When it is determined that the electric vehicle 10 is completely stopped, the inverter 22 is controlled to stop the excitation current to the motor 24 (Step 7).
(See Figure 4).

Note that if it is determined that the motor rotation speed is not zero in the aforementioned 5tep2, if it is determined that the motor rotational speed is not zero in the aforementioned 5tep4, or if it is determined that the brake switch 34 is not in the ON state in the aforementioned 5tep6, the process returns to 5tepl.

Furthermore, if the timer 36 determines that one second has not elapsed in step 5, the operations from step 4 onwards are performed.

On the other hand, when the electric vehicle 10 is in the stopped state, the controller 28 determines whether the brake switch 34 is in the ON state (step 8), and if it is determined that the brake switch 34 is in the ON state, that is, the electric vehicle 10 is stopped,
It is determined whether the motor rotation speed remains zero based on the signal from the rotation speed sensor 26 (5tep 9), and if it is determined that the motor rotation speed is zero, the process returns to 5tep 8.

Further, if the controller 28 determines that the brake switch 34 is not in the ON state in the aforementioned 5tep 8, or if it determines that the motor rotation speed is not zero in the aforementioned 5tep9, that is, if it determines that there is movement in the electric vehicle 10, the controller 28 switches the brake switch 34 to the motor 24. The inverter 22 is controlled to send excitation current (Step 1O).

In addition, when braking, a part of the regenerated power is sent to the brake lamp 4.
If the power is configured to be supplied to 0, it is possible to supply electric power to the brake lamp 40 according to the braking force, and it is possible to change the brightness of the brake lamp 40 according to the braking force.

[Effects of the Invention] As explained above, according to the present invention, when the vehicle is in a running state, when it is detected that the rotation speed of the motor is zero for a predetermined period of time or more and the braking brake is in the ON state, the motor is Since the motor is configured to stop the excitation current of the motor while the vehicle is stopped, it is possible to prevent the consumption of battery power and prevent unnecessary temperature rise of the control element. can do.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a motor control device according to an embodiment of the invention, FIG. 2 is a schematic diagram showing the configuration of an electric vehicle according to an embodiment of the invention, and FIG. 3 is a block diagram showing the configuration of an electric vehicle according to an embodiment of the invention. FIG. 4 is a flowchart diagram showing the operation of one embodiment. FIG. 4 is a diagram showing changes in the excitation current. 18... Motor control device 20... Battery 22... Inverter 24... Motor 26... Rotation speed sensor 28... Control unit 34... Brake switch

Claims (1)

[Claims] An electric vehicle that includes a battery that charges and discharges power, an inverter that converts direct current supplied from the battery into alternating current, and a motor that drives drive wheels using the alternating current converted by the inverter. The motor control device includes: a rotation speed sensor that detects the rotation speed of the motor; a brake switch that detects ON/OFF of a brake that brakes the vehicle; and a control unit that inputs detection signals of the rotation sensor and the brake switch. Preparation: When the vehicle is in a running state, the control unit determines that the rotational speed of the motor is zero for a predetermined time or more based on a signal from a rotational speed sensor, and the brake is in an ON state based on a signal from a brake switch. 1. A motor control device for an electric vehicle, which controls an inverter to stop supplying an excitation current to a motor when detected.