JPS6029359Y2 - Motor rotation control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for controlling the rotational speed of a motor to maintain a constant rotation speed, and particularly relates to a rotation control device for a motor whose rotational direction is difficult to reverse, such as an AC servo motor. .

A common motor usually has torque-voltage characteristics as shown in FIG.

The slope of this characteristic curve becomes gentler as the voltage E becomes smaller.

Therefore, if the motor is used at a low voltage E, sufficient torque cannot be generated to withstand external disturbances applied to the rotation of the motor.

In other words, when a disturbance that acts as a brake is applied to the rotation of the motor, the control device increases the voltage supplied to the motor in order to increase the number of rotations of the motor, but the amount of increase in torque is small in response to this change in voltage. It is.

If it is desired to obtain a large change in torque, a large voltage E may be used, but this is not preferable as it may cause heating of the motor.

Also, if the motor rotation speed is increased due to disturbance,
Alternatively, when the reference rotational speed of the motor is lowered, the control device lowers the motor supply voltage in order to lower the motor rotational speed, but this is sufficient when used in a place where the voltage E is small. It is not possible to obtain a sufficient reduction in torque, and it takes a considerable amount of time to reach the standard rotational speed.

In particular, in record players where the turntable on which the record is placed is directly connected to the rotating shaft of this motor, and the turntable is tilted, the rotational speed increases due to the imbalance in the dynamic balance of the turntable. There are many disturbances that cause the rotation to increase or decrease, and there is a need for effective rotation control means that can be applied in a short period of time to eliminate the effects of these disturbances.

The present invention was developed in view of the above-mentioned current situation, and it is an object of the present invention to provide a device that can reach the standard rotational speed in a short period of time.

An embodiment of the present invention will be described below with reference to the drawings.

What is shown in FIG. 2 is a block diagram of a motor rotation control device according to the present invention.

1 is a motor; 2 is a rotary plate such as a turntable rotated by the motor 1;

For example, a magnetic signal is recorded on the outer periphery of the rotary plate, and this signal is forced to be picked up by the magnetic head 3.

Further, the motor 1 is rotated by a voltage supplied by a motor drive AC power source 4.

The signal picked up by the magnetic head 3 is F
It is demodulated by M demodulator 5, and its output voltage is compared with the voltage of reference voltage generator 7 by comparator 6.

In this comparator 6, the output voltage of the reference voltage generator 7 and F
A voltage different from the output voltage of the M demodulator 5 is generated.

The output voltage of this comparator 6 is applied to the AM modulator 8 and inverter 9.
given to.

This AM modulator 8 changes due to the change in the output voltage of the comparator 6.
This changes the voltage E supplied to the motor 1.

The inverter 9 is used to generate a change opposite to the change in the output voltage of the comparator 6, and its output voltage is directly or indirectly attached to the rotating shaft of the motor 1. is supplied to the auxiliary motor 10, which rotates in a direction opposite to the direction of rotation of the motor.

Therefore, when the rotation speed of motor 1 is increased,
The output voltage of the motor comparator 6, which is difficult to reverse as in an AC servo motor, decreases, and the voltage supplied to the motor decreases.

On the other hand, the output voltage of the inverter 9 increases, and the auxiliary motor 10
The voltage supplied to the motor 1 is increased, and the rotational speed of the motor 1 is decreased until it reaches the reference rotational speed.

Also, when the rotation speed of the motor 1 decreases, the comparator 6
The output voltage of increases, the supply voltage to motor 1 increases,
The voltage supplied to the auxiliary motor is reduced and the rotational speed of the motor 1 is increased to the reference value.

As explained above, in the present invention, since the auxiliary motor is provided, there is an advantage that the deceleration time required to reach the reference rotation speed can be shortened.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram of the motor. FIG. 2 is a block diagram showing one embodiment of the present invention. 1 is a motor, 2 is a rotary plate, 3 is a magnetic head, 4 is a motor drive AC power supply, 5 is an FM demodulator, 6 is a comparator, 7 is a reference voltage generator, 8 is an AM modulator, 9 is an inverter, 10 is an auxiliary motor.

Claims (1)

[Scope of utility model registration request] A main motor directly connected to the motor load, an auxiliary motor coupled coaxially with the main motor and rotated in a direction opposite to the main motor, a detection means for detecting the rotational speed of the load, and the The supply voltage of the main motor is changed to compensate for the variation in the rotation speed of the main motor by the output obtained by comparing the output of the detection means with the reference voltage source, and the supply voltage opposite to the comparison output is supplied to the auxiliary motor. A motor rotation control device characterized by comprising means for controlling the rotation of a motor.