JPH0370489A - Drive circuit for dc motor - Google Patents

Abstract

PURPOSE:To obtain continuity of a torque by providing means for generating a PWM modulation output with the output of means for obtaining an absolute value or inverted output of an error signal in a driving circuit, means for chopping a supply current of a motor, a choke coil connected to the other end of the motor, and a capacitor connected between the ends of the motor. CONSTITUTION:A reference triangular wave input unit 3 is compared with the output of an absolute value circuit 2 by a comparator 4, a speed or a phase error signal is PWM-modulated, and its output and the output of a comparator 6 are input to a controller 7. Switches 13, 14 are controlled by the outputs of the controller 7 and an inverter 17 to be chopped, the output of a choke coil 8 is input to one end of a motor 9, and a capacitor 10 is disposed between both ends of the motor 9 to form a filter.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a drive circuit for a DC motor, and relates to a chisel-twisting type drive circuit suitable for control requiring forward rotational torque and reverse rotational torque. Regarding.

[Conventional technology]

The conventional tick-tubing type drive circuit is disclosed in Japanese Patent Application Laid-open No. 61-106.
As described in the No. 088 publication, the chopped power supply has a source capability, but does not have a sink capability, h'4.

[Fi problem that the invention is supposed to solve]

The above conventional technology requires reverse torque.

It is driven by reversing the polarity, and by supplying a voltage less than the speed electromotive force, it is possible to completely eliminate the discontinuity of torque by applying a reverse torque from the electromagnetic brake. could not.

An object of the present invention is to provide a chi-knobbing type drive circuit that has continuity of torque in the above portion.

[! Means for Solving a Problem] In order to achieve the above object, the chopping type NR is changed to a threading ms using a push-pull method.

Also, in order to make effective use of the power supply, one end of the motor t? This uses a bridge method by switching to the power supply.

[Effect]

Push-pull type switching power supplies can be used even if the output voltage to the other end of the load is positive.

It is possible to have tank ability. Therefore, even if the load has a speed electromotive force, it is possible to apply the υ electromagnetic brake based on the tank capacity.

〔Example〕

Hereinafter, one embodiment of the present invention will be referred to as j7a#1 in FIG.

1 is an input section for a velocity or phase error signal, which is input to the absolute value circuit 2 and the comparator 6. The comparator 6 compares it with the reference voltage 5 and applies the result to the switch 12 or switch 11 to determine whether the voltage to be applied to the motor 9 is positive or negative.

The absolute value circuit 2 takes the absolute value with respect to the reference voltage 5. 5 is the reference triangular wave input section, which is input to the comparator 4,
The speed or phase error signal is PWM'RIA'd by comparing it with the output of the two absolute value circuits. The pwMyRml
The output and the output of the comparator 6 are input to a controller 70. The controller 7 can be configured in many ways, for example as an exclusive fi1 summation. Switches 13 and 1 are connected to the output of the controller 7 and the inverted a17 output.
Control 4 and make it tick. One side of the switch 15 is connected to the source 15, one side of the switch 14 is connected to the power source 16, and the other side of the switch 114 is connected together to input the voltage to the check coil 8. The output of the choke coil 8 is input to one end of the motor 9, and a capacitor 1 is connected between both ends of the motor 9.
0, and the choke coil 8 and capacitor 10 constitute a multi-purpose filter. One side of switch 11 connects + to source 15
Also, one of the switches 12 is connected to one power source 16, and the other of the switches 11 and 120 are connected together and connected to the other end of the motor 90. The switches 11 and 12 are controlled by the comparator 6 output and the inverter 18 output.

Further, a flywheel diode 19 is connected to the outputs of the switches 11 to 14 and the stain source.

Since the output of the PWM modulated speed phase error signal performs the push-pull type tilting operation using the switch 13*14, it has source and sink capabilities even when the voltage across the motor 9 is positive or negative. , 6 motor 9
Even if there is a speed electromotive force due to the rotation of the motor, it is possible to apply an electromagnetic brake due to the sink ability, so continuity of torque can be obtained.

Further, since the switches 11 and 12 provide a bridge system, it is possible to apply a total voltage of ten power sources to the motor.

In this embodiment, PWM modulation is performed by taking the absolute value of the velocity phase error signal, but it is also possible to perform PWM modulation by inverting the reference triangular wave using the output of the comparison 56. Further, the reference voltage 5 can also be set to Ov, which is the reference voltage of the speed phase error signal.

〔Effect of the invention〕

According to the present invention, since it is possible to apply a voltage lower than the speed electromotive force to the motor during electromagnetic play, it is possible to obtain continuity of applied torque and to stabilize the motor servo.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a motor drive circuit as an embodiment of the present invention.

Claims (1)

[Claims] 1. In a DC motor drive circuit that controls the speed of a DC motor by chopping a positive or negative current supplied to the DC motor based on a speed or phase error signal, the error signal voltage level is a certain level. switching means (11, 12) for switching one end of said motor (9) to a positive or negative power supply depending on whether the voltage level is higher or lower than a reference value (5); means (2) for taking a value or a means for taking an inverted output of a reference triangular wave; and means (2) for generating a PWM modulated output from the output from the means (2) for taking an absolute value or the means for taking an inverted output;
4), means (13, 14) for chopping the positive or negative current supplied to the DC motor (9) by a push-pull method according to the output of the generating means (4) and the error signal voltage level; Means to do (1)
3, 14) to the other end of the DC motor (9); and a capacitor (10) connected between both ends of the DC motor (9). A DC motor drive circuit featuring: