JPH0819109A - Controlling method for motor - Google Patents

Abstract

PURPOSE:To prevent the slip of a tire and the vibration of a vehicle body at the time of starting and the decrease of traveling performance by detecting the number of revolutions of a motor according to the signal of an encoder, detecting the vehicle speed by a vehicle speed sensor, and filter-processing a command signal to the motor to an accelerator signal only when the vehicle speed is lower than a predetermined speed. CONSTITUTION:When an accelerator signal is abruptly increased in the state that a vehicle is stopped or at the time of low speed, a command signal to a motor is maximized at once. When the vehicle speed is at a certain speed or less at this time, the accelerator signal is so controlled as to be a curve (a) of the motor command signal. When the speed is the certain speed or more, it is so controlled as to be a curve (b). Then, at the time of starting the vehicle, abrupt torque is not generated and hence the slip of a tire and the vibration of a vehicle body can be prevented. When the tire is a certain speed or more, a filter-process is not executed, but the command remains at the motor command signal as it is, and hence accelerating performance is not dropped, and feeling at the time of starting is also improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a motor which is a drive source of an electric vehicle, for example.

[0002]

2. Description of the Related Art In recent years, the development of electric vehicles has become popular as a measure against environmental problems. A DC motor or an AC motor is used as the power source. Among them, a synchronous motor using a permanent magnet for a rotor has high efficiency, and thus is being actively developed as an electric vehicle.

Conventionally, this type of motor has been widely used for FA and industrial purposes, but the basic control method for electric vehicles is almost the same. Conventionally, since a synchronous motor or the like uses a permanent magnet for the rotor, the reaction at the time of starting is very good, and it is one of the important capabilities when used for FA. However, in the case of an electric vehicle, if the motor generates abrupt torque when the vehicle starts, the tires may idle or the vehicle body may vibrate, which may cause a driver to feel uncomfortable. Therefore, it has been dealt with by subjecting the accelerator signal to filter processing, reducing the gain of the command signal to the motor to slow the reaction to the accelerator signal, and subjecting the command signal to the motor to filter processing.

[0004]

The electric vehicle, of course, is required to have a power performance equivalent to that of an ordinary gasoline engine vehicle. Therefore, in order to improve the reaction of the motor as much as possible, it is necessary to increase the gain of the command signal to the motor with respect to the accelerator signal. However, if the gain is high, tire slipping and vehicle body vibration occur as described above. Therefore, if the filter processing as described above is applied, the response to the accelerator feeling deteriorates.

An object of the present invention is to provide a control method which prevents the tires from spinning and the vehicle body from vibrating when the vehicle starts, and does not deteriorate the running performance in other cases.

[0006]

In order to achieve the above object, the present invention detects the number of revolutions of a motor from a signal of an encoder provided in the motor, or detects a vehicle speed by a vehicle speed detector provided in the vehicle. When the speed is detected and the speed of the vehicle is slower than a certain speed, the command signal to the motor for the accelerator signal is filtered to prevent tire slipping and vibration of the vehicle body when the vehicle starts, and when the speed is higher than a certain speed. Does not reduce the running performance by not performing filtering.

[0007]

With the above structure, the present invention prevents the tire from idling and the vehicle body from vibrating when the speed of the vehicle is lower than a certain speed, that is, when the vehicle starts, and does not deteriorate the running performance when the speed is higher than a certain speed. it can.

[0008]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a circuit block diagram of a motor control device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is a motor, such as a synchronous motor, which is a drive source of an electric vehicle. Reference numeral 2 is an encoder that is provided in the motor 1 and outputs an A-phase signal and a B-phase signal.

Reference numeral 3 is an address generating means for generating a digital address signal corresponding to the rotor position of the motor 1 based on the Z-phase signal, the A-phase signal and the B-phase signal output from the encoder 2.

Reference numeral 4 is a speed or torque command input (accelerator input, brake input) and A output from the encoder 2.
It is a speed control unit including a CPU that outputs a speed command signal and a torque command signal corresponding to the difference between the rotation speed of the motor 1 obtained from the phase signal and the B phase signal.

Reference numeral 5 stores the waveform data for driving the motor 1 for one cycle, and uses the digital address signal output from the address generating means 3 as an address input to output the waveform data sin θ for driving the motor 1 to the rotor position of the motor 1. The waveform storage means is composed of a ROM or the like for reading in correspondence with the above.

Reference numeral 6 adds the speed or torque control command signal output from the speed control means 4 to the waveform data for driving the motor 1 output from the waveform storage means 5, and performs digital / analog conversion on the addition result. (Hereafter, D
/ A conversion) for performing integrated D / A conversion means.

Reference numeral 7 is a current control circuit for outputting an error signal between the output signal of the integrated D / A conversion means 6 and the detection signal of the load current flowing in the motor 1 by a current transformer or the like.

Reference numeral 8 is a pulse width modulation (hereinafter referred to as PWM) which generates a pulse width modulation signal according to the output signal of the current control circuit 7.
It is a control circuit.

A PWM inverter 9 drives the motor 1 according to the output signal of the PWM control circuit 8.

The operation of the motor control device having the above configuration will be described below with reference to FIG.

For example, when the accelerator signal suddenly increases from the state where the vehicle is stopped or when the vehicle speed is low, the command signal to the motor becomes maximum. Therefore, the vehicle speed S is a certain speed M
When N or less, the motor command signal MS is set to S <MN MS = AS * K / T * t with respect to the accelerator signal AS (...
The curve a) is controlled so that However, K is a constant, T is the time for filtering, and t is the time from the accelerator input. When the speed S of the vehicle is equal to or higher than MN, S> MN MS = AS * K ... (Curve b in FIG. 2) and no filter is provided. By controlling in this way, a sudden torque is not generated when the vehicle starts, so that the tire does not idle and the vehicle body does not vibrate. However, when the tire starts to rotate to some extent, the inertial force of the vehicle decreases toward the acceleration side, so even if there is a sudden torque generation, the tire will not idle or the vehicle body will not vibrate, so in this case do not filter. The accelerator command is used as it is as a motor command signal. Therefore, the acceleration performance does not deteriorate and the feeling at the start can be improved.

As the above filter processing, MS = AS * K (1-e- ^{t / T} ) ... (Curve c in FIG. 2) MS = AS * K (1- (1 + t / T) e- ^{t / T} ...
Needless to say, the same effect can be obtained by using (curve d in FIG. 2) or the like.

(Embodiment 2) Another embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, the conditions similar to those in FIG. 1 are detected, and the speed S of the vehicle is detected by the speed detector 10 provided in the vehicle, and the same control as in the first embodiment is performed. Of course, the same effect as that of the first embodiment can be obtained.

[0022]

As is apparent from the above description, according to the present invention, no sudden torque is generated when the electric vehicle is started, so that the tire does not idle and the vehicle body does not vibrate. Further, when the tire is at a certain speed or higher, the accelerator command is directly used as the motor command signal without performing the filtering process, so that the acceleration performance is not deteriorated and the feeling at the start can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a motor control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a motor command in response to an accelerator command according to an embodiment of the present invention.

FIG. 3 is a block diagram showing the configuration of a motor control device according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 motor 2 encoder 3 address generation means 4 speed control means 5 waveform storage means 6 integration D / A conversion means 7 current control circuit 8 PWM control circuit 9 PWM inverter 10 speed detector

Claims (2)

[Claims] 1. A control of a motor, which detects a rotation speed of the motor from an output signal of an encoder provided in a motor of an electric vehicle and delays a command signal to the motor with respect to an accelerator input signal at a predetermined rotation speed or less. Method. 2. A motor control method for detecting a vehicle speed by a vehicle speed detector separately provided in an electric vehicle, and delaying a command signal to the motor with respect to an accelerator input signal at a constant vehicle speed or less.