JP2001224108A - Motor control device for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable conducting highly accurate control of speed, acceleration and deceleration with gain, when controlling a driving motor for an electric vehicle. SOLUTION: In a motor control device for an electric vehicle, that determines the target speed at that time from the opening of an accelerator, obtains a command speed that corresponds to the determined target speed and a current speed by a given processing, and controls the motor in accordance with the command speed, means are provided that obtain command acceleration and deceleration by a given processing making use of each detected value of the opening of the accelerator and the current speed, the target speed, and the preset limit values of the maximum acceleration and deceleration of the vehicle, that revise the command speed using the obtained command acceleration and deceleration, and that calculate torque that makes the deviation between the revised command speed and the current speed close to zero, to control motor torque in accordance with the calculation result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for an electric vehicle which controls a driving motor in the electric vehicle.

[0002]

2. Description of the Related Art Generally, in an electric vehicle such as a golf cart, the maximum speed is limited to about 20 km / h, and when the maximum speed is exceeded, a process of cutting a motor torque is performed. It becomes necessary, and in that case, driving of the motor becomes unnatural and gives a feeling of strangeness to driving.

The general torque characteristics of a motor are shown in FIG.
When the output torque is set to 100% at the accelerator opening of 100%, an excessive torque is generated in a low speed range, and the drive feeling deteriorates. Therefore, as shown by the dotted line in the figure, when the limiter control is performed such that the torque of the motor is suppressed to a certain value or less in a low speed range, the drive feeling is improved, but the motor performance cannot be sufficiently exhibited. Acceleration becomes worse.

Conventionally, in order to enable smooth acceleration, a target speed at that time is determined from each detection result of the accelerator opening and the current speed of the vehicle.
An electric vehicle in which a command speed considering a speed change rate necessary for causing the current speed to converge to the determined target speed is determined by predetermined arithmetic processing, and the number of rotations of the motor is controlled according to the command speed. (See JP-A-6222805).

[0005]

A problem to be solved is that a motor speed of a conventional electric vehicle is controlled by obtaining a command speed from a target speed determined according to an accelerator opening to control the number of rotations of the motor. In the control device, when the accelerator pedal is suddenly depressed, the target speed changes suddenly and the deviation between the commanded speed and the current speed becomes large, so the control gain must be set considerably low to perform smooth acceleration. Therefore, it takes time to converge on the target speed, and the controllability deteriorates.

[0006] Further, in such a conventional motor control device for an electric vehicle, it is not possible to perform control for smooth deceleration while limiting the traveling speed on a downhill.

[0007]

According to the present invention, a target speed at that time is determined from an accelerator opening, and a command speed corresponding to the determined target speed and the current speed is obtained by a predetermined arithmetic processing. In a motor control device for an electric vehicle that controls the motor according to the command speed, the current speed is controlled while limiting the running speed even when the accelerator pedal is suddenly depressed or when going downhill. In order to optimally control acceleration and deceleration for converging to the target speed, the detected values of the accelerator opening and the current speed, the target speed, and the preset limit values for the maximum acceleration and deceleration of the vehicle are used. The command acceleration / deceleration is determined by the predetermined arithmetic processing, and the command speed is updated using the determined command acceleration / deceleration, and the deviation between the updated command speed and the current speed approaches zero. Calculated and is acceptable to provide a means for performing the torque control of the motor in accordance with the calculation results.

[0008]

FIG. 1 shows an example of the configuration of a motor control device for an electric vehicle for carrying out the present invention.

The motor control device for an electric vehicle includes an accelerator opening detector 1 for detecting an accelerator opening, a speed detector 2 for detecting a current speed of the vehicle, and respective detection values of the accelerator opening and the current speed. And calculating a predetermined target speed from a preset table and performing a predetermined calculation process to obtain a motor drive control amount for converging the current speed to the target speed. The motor control unit 4 controls the drive of the motor 6 via the inverter 5 according to the obtained control amount.
The rotation speed N of the motor 6 is detected by the rotation detector 7, and the rotation speed N is fed back to the motor control unit 4.

The arithmetic processing unit 3 and the motor control unit 4 are specifically constituted by an ECU. As the motor 6, for example, a three-phase magnet synchronous generator capable of controlling torque is used.

The present invention is configured as described above, and basically, in the arithmetic processing unit 3, the command speed is determined by taking into account the speed change rate necessary for converging the current speed to the target speed. Is calculated by the above calculation processing.

The command speed Vs in consideration of the speed change rate ΔV required to converge the current speed V to the target speed Vo is obtained by a calculation process based on the following equations (1) and (2).

Vs = Vo−ΔV (1)

ΔV = K / (Vo−V) (2) K: constant

In particular, the present invention provides a command processing by a predetermined arithmetic processing using each detected value of the accelerator opening and the current speed, a target speed, and a preset limit value of maximum acceleration and deceleration of the vehicle. Means for determining the deceleration, means for updating the command speed using the obtained command acceleration and deceleration,
Means for calculating a torque that brings the deviation between the updated command speed and the current speed close to zero is employed, and the drive of the motor 6 is controlled using the calculated torque as a control amount.

These means are executed in the arithmetic processing unit 3.

FIG. 2 shows a specific processing flow in the arithmetic processing unit 3. Specific processing according to the flow will be described below.

First, the accelerator opening H (%) and the current speed V are detected at regular intervals ΔT (step S1), and a predetermined table is set according to the detected accelerator opening H in accordance with the detected accelerator opening H. The target speed Vo is obtained (Step S2).

Next, it is determined whether or not the obtained target speed Vo is higher than the current speed V (step S3). If Vo> V at that time, the process enters the acceleration mode, and Vo ≦ V If so, the process enters the deceleration mode.

In the processing in the acceleration mode, it is determined whether or not the command speed Vs obtained as described above is lower than the current speed V (step S4). The command speed Vs at that time is rewritten and reset so that it becomes the same value as the current speed V (step S5).

If Vs ≧ V, it is determined whether the command speed Vs is higher than the target speed Vo (step S6). If Vs> Vo, the command speed Vs at that time is determined. Is rewritten and reset to the same value as the target speed Vo (step S7). At that time, if Vs ≦ Vo, the command speed Vs is not reset at all.

Next, the acceleration 1 is obtained by multiplying a preset limit value of the maximum acceleration by the accelerator opening H (step S8), and a deviation between the target speed Vo and the current speed V is multiplied by a predetermined acceleration gain. Thus, the acceleration 2 is obtained (step S9), and it is determined whether the acceleration 1 is smaller than the acceleration 2 (step S1).
0).

At this time, if acceleration 1 <acceleration 2,
The command acceleration α is set to be the acceleration 1 (step S11). If acceleration 1 ≧ acceleration 2, the command acceleration α is set to be acceleration 2 (step S
12).

The command speed Vs is updated by adding a speed component obtained by multiplying the set command acceleration α by a certain period (period) ΔT to the command speed Vs at that time (step S13).

FIG. 3 shows a torque characteristic with respect to a speed deviation between the current speed V and the target speed Vo using the accelerator opening H as a parameter. The acceleration 2 indicates a rising characteristic from a speed deviation of 0, and the acceleration 1 indicates a rise characteristic. It shows the characteristics after the rise.

Next, it is determined whether or not the updated command speed Vs is greater than the current speed V plus a preset speed deviation limit value (step S1).
4).

At this time, if the command speed Vs is higher, a speed deviation Err between the command speed Vs and the current speed V is obtained (step S15). If the command speed Vs is smaller, the command speed Vs plus the speed deviation limit value is used as the new command speed Vs (step S1).
6) The speed deviation Err between the new command speed Vs and the current speed V is obtained (step S15).

Then, finally, a torque that brings the speed deviation Err closer to zero is calculated as a proportional control component (Err + P gain) + an integral control component (ΣErr + I gain) (step S17).

In the acceleration mode processing, it is determined whether or not the command speed Vs obtained as described above is higher than the current speed V (step S18).
If s> V, the command speed Vs at that time becomes the current speed V
Is rewritten so as to have the same value as, and reset (step S19).

If Vs ≦ V, it is determined whether the command speed Vs is lower than the target speed Vo (step S20). If Vs <Vo, the command speed Vs at that time is determined. Is rewritten so as to have the same value as the target speed Vo and reset (step S21). At that time, if Vs ≧ Vo, no reset of the command speed Vs is performed.

Next, the deceleration is obtained by multiplying the deviation between the current speed V and the target speed Vo by a predetermined deceleration gain (step S22), and determines whether the deceleration is greater than a preset maximum deceleration. It is determined whether or not it is (step S23).

At that time, if deceleration> maximum deceleration,
The command deceleration β is set to be the maximum deceleration (step S24). If deceleration ≦ maximum deceleration, the command deceleration β is set to be the deceleration at that time (step S25).

Then, the command speed Vs is updated by adding a speed component obtained by multiplying the set command deceleration β by a certain period (period) ΔT to the command speed Vs at that time (step S26).

Next, it is determined whether or not the updated command speed Vs is smaller than the current speed V plus a preset speed deviation limit value (step S2).
7).

At this time, if the commanded speed Vs is smaller, a speed assist difference Err between the commanded speed Vs and the current speed V is obtained (step S15). If the command speed Vs is higher, the command speed Vs plus the speed deviation limit value is used as the new command speed Vs (step S2).
8) The speed deviation Err between the new command speed Vs and the current speed V is obtained (step S15).

Then, finally, a torque for bringing the speed error Err closer to zero is calculated as a proportional control component (Err + P gain) + an integral control component (ΣErr + I gain) (step S16).

As described above, according to the present invention, the command speed Vs approximated to the current speed Vo by a predetermined rule with respect to the target speed Vo determined by the accelerator opening H.
Is generated, the accelerator opening H, the current speed V, and the target speed Vo
And command acceleration and deceleration α, which are obtained by a predetermined calculation process using preset maximum acceleration and deceleration limit values,
The command speed Vs is updated using β, and a so-called follow-up control is performed by using a torque that brings the deviation between the updated command speed Vs and the current speed V close to zero as a control amount, so that the motor 6 has a high gain. Can be controlled, and the speed and acceleration / deceleration can be controlled with high accuracy.

[0038] Therefore, automatically increasing or decreasing the weight of the vehicle body, suddenly depressing the accelerator pedal, or changing running conditions (running on uphill, downhill or flat road, running resistance due to wind, etc.). Since the torque is adjusted, the drive feeling is improved. In particular, since a negative torque due to regenerative braking is applied to the motor 6 on a downhill, smooth deceleration control can be performed while limiting the speed.

[0039]

As described above, in the motor control device for the electric vehicle according to the present invention, the target speed at that time is determined from the accelerator opening and the command speed according to the determined target speed and the current speed is determined. When the motor is controlled in accordance with the commanded speed, which is obtained by a predetermined arithmetic processing, the detected values of the accelerator opening and the current speed, the target speed, and the preset limit values of the maximum acceleration and deceleration of the vehicle. The command acceleration and deceleration are obtained by a predetermined arithmetic processing using, and the command speed is updated using the obtained command acceleration and deceleration, and the deviation between the updated command speed and the current speed is reduced to zero. Since the approaching torque is calculated and the motor torque control is performed according to the calculation result, it is possible to control the speed and acceleration / deceleration with high gain with high accuracy. It has the advantage.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a motor control device of an electric vehicle for implementing the present invention.

FIG. 2 is a diagram showing a specific processing flow in an arithmetic processing unit having the same configuration example.

FIG. 3 is a diagram showing a torque characteristic with respect to a speed deviation between a current speed and a target speed using an accelerator opening as a parameter.

FIG. 4 is a diagram showing general torque characteristics of the motor in the configuration example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Accelerator opening detector 2 Speed detector 3 Operation processing unit 4 Motor control unit 5 Inverter 6 Motor 7 Rotation detector

Claims (3)

[Claims] An accelerator opening and a current speed of a vehicle are detected, a target speed is determined from the detected accelerator opening, and a command speed corresponding to the determined target speed and the current speed is determined by a predetermined speed. In a motor control device for an electric vehicle, which is obtained by arithmetic processing and controls a motor so as to achieve the command speed, detection values of an accelerator opening and a current speed, a target speed, a preset maximum acceleration of the vehicle, Means for obtaining command acceleration and deceleration by predetermined arithmetic processing using the deceleration limit value; means for updating the command speed using the obtained command acceleration and deceleration; A motor control device for an electric vehicle, comprising: means for calculating a torque that makes a deviation from a current speed close to zero; and means for performing torque control of a motor in accordance with the calculation result. 2. A first acceleration is obtained by using an accelerator opening and a limit value of a maximum acceleration of the vehicle, and a second acceleration based on a deviation between a target speed and a current speed is obtained.
When the first acceleration is smaller than the second acceleration, the first
2. The motor control device for an electric vehicle according to claim 1, wherein the first acceleration is the command acceleration, and the second acceleration is the command acceleration when the first acceleration is equal to or higher than the second acceleration. 3. A deceleration based on a deviation between a current speed and a target speed is determined. If the determined deceleration is equal to or less than a maximum deceleration limit value, the deceleration is set as a commanded deceleration. 2. The motor control device for an electric vehicle according to claim 1, wherein when the deceleration is larger than the maximum deceleration limit value, the maximum deceleration limit value is set as the command deceleration.