JP2001061202A - Safety protection method of electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to detect an abnormal state easily by judging that there is an abnormality if a drive motor rotates continuously for a specified period of time at a speed equal to or more than a specified one when the accelerator is off and the shift lever is in the neutral position. SOLUTION: This method starts with the judgment as to whether or not an accelerator is off. If it is off, it is judged whether or not the shift lever is in a neutral position. If it is, since the rotational speed of a motor is controlled with a command variable from a controller, whether the control is normal or abnormal can be judged by monitoring the rotational speed. When it is judged to be neutral, it is judged whether the motor is rotating at a specified rotational speed or more. If that state continues for a specified period of time or longer, it is judged to be abnormal, and an inverter is stopped to interrupt the motor control. This method makes it possible to easily detect the abnormal state that the current is not flowing in accordance with the command variable at the time of the regenerative operation of the drive motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for protecting a control device mounted on a controller of a motor for driving an electric vehicle.

[0002]

2. Description of the Related Art In recent years, electric vehicles without exhaust gas have attracted attention from the viewpoint of global environmental protection. The drive motor of this electric vehicle functions as a generator during regeneration to charge the battery.

[0003] Among the configurations for controlling the current of the drive motor, in a control configuration in which a component for controlling an actual motor current as instructed by hardware without using a microprocessor or the like, an actual configuration is used. The current is often configured without a check function for confirming that the current flows as instructed including the current phase.

Further, the reliability of motor control is established by ensuring the reliability of the components that are configured.

[0005]

However, in the above-described conventional configuration, if the current cannot be controlled according to the command value including the current phase, the actual current flows at the powering phase despite the regenerative command, or the current does not flow. The opposite symptoms appear.

When the current phase is actively controlled using field weakening control or the like, the probability of occurrence of the above-mentioned phenomenon increases unless the motor current is controlled exactly according to the command value. was there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and provides a highly safe safety protection method which can easily detect an abnormal state in which a current does not flow according to a command value when a driving motor is regenerated. The purpose is to provide.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a control device for an electric vehicle for performing regenerative control when an accelerator is off, wherein the accelerator is off and the shift position is neutral. In this state, it is determined that the drive motor is abnormal when the drive motor continuously rotates for a specified period of time at or above the specified number of revolutions.

In addition, when the battery current is observed and the accelerator-off is detected, it is determined that an abnormality has occurred when the battery current continues to flow in a direction of consuming a specified value or more despite the regenerative control for a specified time. Things.

The motor control inverter is stopped when it is determined that there is an abnormality, and a malfunction of the control device is detected to ensure the safety of the electric vehicle.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS To solve the above-mentioned problems, the present invention relates to a control device for an electric vehicle that performs regenerative control when an accelerator is off, wherein the accelerator is off and the shift position is in a neutral state. This is a safety protection method for an electric vehicle in which a drive motor is determined to be abnormal when the drive motor continuously rotates for a specified period of time at or above a specified number of revolutions.

In addition, when the battery current is observed and the accelerator-off is detected, it is determined to be abnormal when the state in which the battery current flows in a direction of consuming a specified value or more despite the regenerative control continues for a specified time. This is a safety protection method for electric vehicles.

Further, the present invention is the safety protection method for an electric vehicle according to claim 1 or 2, wherein when it is determined that the abnormality is abnormal, the motor control inverter is stopped.

Thus, in the regenerative state of the accelerator off,
When the brake is depressed, the rotation speed is rapidly reduced, and the rotation speed is gradually reduced even when the brake is not depressed. Therefore, it can be determined that a state where the rotation speed is equal to or more than the specified rotation speed continues for a long time is abnormal.

Further, by observing the battery current, since the battery is in the charging direction in the regenerative state in which the accelerator is off, it can be determined that the battery current is abnormal if the battery current flows in a direction that consumes a specified value or more.

Further, when it is determined that there is an abnormality, the motor control inverter is stopped to ensure the safety of the electric vehicle.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a flowchart for explaining Embodiment 1 of the present invention.

In the control method in which the control of stopping the motor rotation by regenerative braking when the accelerator of the electric vehicle is in the off state, when the accelerator is off, the motor cannot generate the power running torque and continue to rotate.

Therefore, as shown in FIG. 1, first, the state of the accelerator is monitored to determine whether or not the accelerator is off.

Next, if the accelerator is in the off state, it is determined whether the shift position is in the neutral state. If the shift is in the neutral state, the motor rotation is controlled by a command value from the controller regardless of the state of the vehicle. Therefore, it is possible to determine whether the motor is normal or abnormal by observing the rotation of the motor.

If it is determined that the motor is in neutral, it is determined whether the motor is rotating at a motor rotation speed of a specified value (for example, 3500 rpm) or more. Judge. If it is determined to be abnormal, the inverter is stopped immediately and the motor control is stopped.

(Embodiment 2) FIG. 2 is a flowchart for explaining Embodiment 2 of the present invention.

In FIG. 2, it is determined whether the motor current is controlled according to the command value regardless of the shift position.

As in the first embodiment, when a battery is used as a power source for driving the motor when the accelerator is off, regenerative energy may be recovered to the battery but energy is consumed from the battery. No current can flow in that direction.

Therefore, as shown in FIG. 2, first, it is determined whether or not the accelerator is off, and if the accelerator is off, the battery current is observed next.

It is determined whether the battery current exceeds a specified value (for example, 10 A) including a plus sign when taking out energy from the battery and a minus sign and a plus / minus sign when returning energy to the battery. Specified value (10A)
Is determined to be abnormal, if the state continues for a specified value (for example, 3 seconds) or more.

If it is determined that there is an abnormality, the inverter is immediately stopped, and the motor control is stopped.

It should be noted that the rotation speed, time,
It goes without saying that the specified value of the battery current value is a constant that greatly varies depending on the vehicle type, motor characteristics, battery type, and the like.

[0030]

As is apparent from the above embodiment, according to the first or second aspect of the present invention, it is possible to easily detect an abnormal state in which a current does not flow according to a command value during regeneration of the driving motor. Therefore, safety of the electric vehicle can be ensured.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating a second embodiment of the present invention.

Claims (3)

[Claims] 1. A control device for an electric vehicle that performs regenerative control when an accelerator is in an off state. A safety protection method for an electric vehicle that determines that it is abnormal when it rotates continuously for a specified time. 2. A control device for an electric vehicle that performs regenerative control when an accelerator is off, monitors a battery current, and when the accelerator is off, consumes the battery current not less than a specified value despite regenerative control. A safety protection method for an electric vehicle that determines that an abnormality has occurred when the vehicle is flowing for a specified period of time. 3. The safety protection method for an electric vehicle according to claim 1, wherein when it is determined that the abnormality is abnormal, the motor control inverter is stopped.