JPH0787641B2 - Electric vehicle motor control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for controlling a motor for an electric vehicle, and more particularly to controlling a current supplied to a driving motor.

[Prior Art] Conventionally, in speed control of an electric vehicle, a traveling speed is controlled by controlling a power supply amount to a drive motor according to an accelerator opening degree. However, according to such control means, for example, when the accelerator pedal and the brake pedal are depressed at the same time, the motor is forcibly brake-braked while current is flowing to the motor to generate a rotational force corresponding to the accelerator opening at that time. As a result, an excessive current flows through the motor, which may cause the main fuse to break or the coil to burn.

In order to solve such a problem, in Japanese Patent Laid-Open No. 57-31301, a brake switch that operates when the brake pedal is depressed is provided so that the power supply to the traveling motor is cut off by the operation of the brake switch. Then, a proposal has been made to prevent the motor lock current from flowing even when the accelerator pedal and the brake pedal are depressed at the same time.

According to this conventional technique, the motor lock current is not generated even when the brake is applied, and the adverse effects such as the breaking of the main news are prevented.

[Problems to be Solved by the Invention] Conventional Problems However, in the above-described conventional technique, if the accelerator pedal fails to return or the accelerator sensor fails, the current flows to the motor if the brake pedal is depressed. However, when the brake pedal is released, a current flows into the motor due to the offset voltage of the accelerator pedal so as to generate a rotational force corresponding to the accelerator opening degree of the accelerator pedal at that time, and a revolving power is generated.

Therefore, when the accelerator pedal returns to a defective state, the driver must continue to depress the key switch in order to stop the motor, which is an unfavorable situation.

An object of the present invention is to solve the above problems, and to provide an electric vehicle motor that prevents the motor from being driven regardless of the driver's intention even if the accelerator sensor causes a return failure. The purpose is to provide a control method.

[Means and Actions for Solving Problems] In order to achieve the above object, the present invention outputs an accelerator sensor that outputs a signal corresponding to an accelerator opening and a signal indicating whether or not a brake is in operation. Control of a motor for an electric vehicle, which includes a control computer for controlling the rotational force of the drive motor based on a signal from a brake switch, and controls the drive motor via an inverter main circuit based on a calculation result by the control computer In the method, when the brake switch is on, the actual accelerator opening signal value is set as the offset signal value when the accelerator is fully closed, and the drive motor is controlled with the accelerator fully closed. Is the value obtained by subtracting the offset signal value from the actual accelerator opening signal value. To is characterized in that so as to control the driving motor.

With the above configuration, according to the method of the present invention, when the brake switch is turned on, even if the accelerator opening signal value at this time is equal to or more than the signal value originally assumed as the accelerator fully closed state, the accelerator opening at this time is opened. Degree voltage is regarded as the accelerator fully closed state and the drive motor is controlled, and the accelerator opening signal value at this time is set as an offset signal value.
This offset signal value is stored. Then, even after the brake switch is turned off next time, the accelerator is judged to be opened only when the accelerator opening signal value equal to or greater than the stored offset signal value is input, and the actual accelerator opening degree is determined. The current corresponding to the difference between the signal value and the stored offset signal value is supplied to the drive motor.

As a result, even if the accelerator pedal returns badly or the accelerator sensor fails, once the brake switch is turned on, the accelerator opening signal value at this time is stored as the offset signal value when the accelerator is fully closed. Thus, it is possible to prevent the motor from being driven regardless of the driver's intention.

[Embodiment] A preferred embodiment of the method of the present invention will be described below with reference to the drawings.

FIG. 2 shows a system block diagram used in this embodiment.

In the figure, an accelerator sensor 10 that outputs a signal of a voltage corresponding to the accelerator opening and a brake switch 12 that outputs a signal indicating whether or not the brake is operating are provided.
The signals from the accelerator sensor 10 and the brake switch 12 are input to the control computer 14. The control computer 14 performs a calculation for controlling the rotational force of the drive motor 16 based on the signals from the accelerator sensor 10 and the brake switch 12, the calculation result is input to the inverter main circuit 18, and the motor 16 is The rotation is controlled according to the calculation amount.

Here, the characteristic of the present invention is that when the brake switch is in the ON operation state, this actual accelerator opening signal value is set as an offset signal value when the accelerator is fully closed, and the accelerator opening degree at this time is set. The motor is controlled assuming that the accelerator is fully closed, and when the brake switch is off, the value obtained by subtracting the offset signal value from the actual accelerator opening signal value at that time is used as the accelerator opening signal value for driving. That is, the motor is controlled.

That is, according to the present embodiment, the control computer 14 is a storage unit 20 that stores the accelerator opening voltage, which is the accelerator opening signal value, and the accelerator opening voltage when the brake switch is in the ON operation state, It includes a comparison calculation unit 22 that compares the actual accelerator opening voltage when the brake switch is in the OFF state, and the motor with a current corresponding to the comparison value at this time.
Control 16

FIG. 1 shows a flowchart of motor control according to the method of this embodiment.

First, in step 100, it is determined whether or not the brake switch is in the ON state. When the brake switch is in the ON state, in step 110, the accelerator opening voltage (V _ACL ) which is the accelerator opening signal value indicating the accelerator opening. Is read. At this time, if the accelerator sensor is operating normally, the accelerator voltage at this time is normally read as the voltage corresponding to the accelerator opening when fully closed, but if the accelerator sensor is not returning properly, or if the brake When the accelerator and the accelerator are both depressed at the same time, the accelerator opening voltage becomes a value equal to or higher than the fully closed voltage.

In step 120, the accelerator opening voltage at this time is set as an offset voltage (Vofst) which is an offset signal value, and this offset voltage is stored in the storage unit in the control computer. In this case, the brake switch has priority over the accelerator opening, so step 13
At 0, the accelerator opening is the offset voltage (Vofst)
In case of, the torque command (Tref) to the motor is 0. Then, in the inverter control routine of step 140, the transistors in the inverter main circuit are on / off controlled so that the torque corresponds to the torque command (Tref) = 0 at this time.

In the present embodiment, as shown in the flow chart of FIG. 1, while the brake is in the ON operation state, the actual accelerator opening voltage at that time is continuously read, and the accelerator voltage at the time of fully closing the accelerator is read. Since it is updated and set as the offset voltage, the accelerator pedal that is causing the return failure moves while the brake pedal is being pressed, or the accelerator pedal and the brake are intentionally simultaneously pressed while the accelerator pedal is being pressed. Even if the depression state fluctuates and the accelerator opening fluctuates, the latest offset voltage can be stored, so that the control can be favorably performed when the brake pedal is released thereafter.

Note that the present invention is not limited to this, and the first actual accelerator voltage at that time may be stored as an offset voltage only at the moment when the brake switch shifts from the off state to the on operating state.

On the other hand, in step 100, when the brake switch is in the off state, the actual accelerator opening voltage (V _ACL ) at that time is read in step 150, and the offset voltage (Vofst) in step 120 stored when the brake switch is turned on is stored. The difference (V _ACL −Vofst) is newly set as the accelerator opening voltage (step 160),
A torque command corresponding to the accelerator voltage is calculated (step 170).

That is, in the flow chart of the present embodiment, even when the accelerator sensor fails to return, by setting a new offset voltage (Vofst), as shown in FIG. The torque control described above can be performed, and once the brake pedal is depressed, the accelerator is apparently fully closed and the subsequent torque command is calculated.

By the way, according to the conventional control means, for example, when the accelerator return failure occurs, the vehicle speed is increased irrespective of the driver's intention. In this case, however, the driver temporarily puts his foot on the brake. I try to stop, but at the moment when I release my foot from the brakes, the speed of the vehicle increases again and I am very confused.

However, according to the embodiment of the present invention, when the speed of the vehicle is increased against the driver's intention due to a poor accelerator return, the rotational force of the motor becomes zero simply by putting a foot on the brake,
Since the rotational force of the motor continues to be 0 even when the foot is released from the brake, the driver can drive safely without being confused.

[Effects of the Invention] As described above, the present invention sets the accelerator opening signal value at that time when the brake switch is in the ON operation state as the offset signal value when the accelerator is fully closed, and uses the offset signal value at this time as a reference. By performing the motor control thereafter, it is possible to prevent the motor from being driven irrespective of the driver's intention due to a defective accelerator return or the like.

[Brief description of drawings]

FIG. 1 is a diagram showing a flow chart of a motor control used in a preferred embodiment of the method of the present invention, FIG. 2 is a system block diagram used in a preferred embodiment of the method of the present invention, and FIG. It is a figure which shows the relationship with the torque instruction | command to a motor. 10 …… Accelerator sensor 12 …… Brake switch 14 …… Control computer 16 …… Drive motor 18 …… Inverter main circuit

Claims (1)

[Claims] 1. A control for controlling the rotational force of a drive motor based on a signal from an accelerator sensor that outputs a signal corresponding to an accelerator opening and a brake switch that outputs a signal indicating whether a brake is operating. In a method for controlling a motor for an electric vehicle, which comprises a computer for control and controls a drive motor via an inverter main circuit based on a calculation result by the control computer, an actual accelerator opening signal when a brake switch is in an ON operation state. Set the value as the offset signal value when the accelerator is fully closed, control the drive motor with the accelerator fully closed, and when the brake switch is in the off state, subtract the offset signal value from the actual accelerator opening signal value A motor for an electric vehicle characterized in that a drive motor is controlled as an opening signal value. Data control method.