JPH0724960Y2 - DC motor controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control device for a control DC motor used for mode switching of an air conditioner, adjustment of an air mix door, and the like.

(Prior Art) A conventional example is shown in FIG. In FIG. 5, 1 is a control DC motor, 2 is a motor potentiometer, 3 is a motor driver, 4 and 5 are comparators, 6 is a reference voltage generating circuit for generating reference voltages Va, Vb, Vc, and 7 is This is an operational amplifier that takes the difference voltage between the set voltage Via and the detection voltage Vib of the motor potentiometer 2 with reference to the reference voltage Vc of the reference voltage generation circuit 6 and amplifies the output voltage Vo of the amplifier 7 and the reference voltage. Va and Vb are compared by the comparators 4 and 5, the comparison result is given to the driver 3, and the motor 1 is operated so that Va>Vo> Vb. That is, the motor 1 is controlled so that the object to be driven by the motor 1 is at a required position.

In this case, however, the reference voltage generating circuit 6 obtains the voltage V'cc, which is a constant voltage by a three-terminal regu- lator, a zener diode, etc., by dividing it with a resistor, etc., so that the power supply voltage of the motor 1 changes. Also, the reference voltages Va, Vb, Vc are always constant, and when the motor power supply voltage rises and its torque increases, the output signal Vo of the amplifier 7 changes the dead zones Va to Vb of the comparators 4,5.
As a result, the speed at which the motor passes through becomes faster, and it may not be possible to stop with the stop signal of the motor generated in the dead zone Va to Vb. That is, the reverse rotation control signal is input to the motor beyond the dead zone with respect to the motor stop signal. As a result, the direction of rotation of the motor goes through the dead zone and repeats forward / reverse rotation, making it impossible to stop the motor. A so-called continuous lock state of the motor 1 occurs.

(Object of the Invention) It is an object of the present invention to provide a DC motor control device capable of performing accurate control without causing a continuous lock state even when the power supply voltage of the motor changes.

(Summary of the Invention) The present invention has a dead band between a motor potentiometer that interlocks with a control DC motor, a motor driver that supplies drive power to the control DC motor, and two reference voltages.
A window comparator that gives a reverse or forward control signal to the motor driver when the input is above and below, and two reference voltages of this window comparator and a reference voltage generation that generates a reference voltage in the middle by voltage division by a resistor. DC motor control device including a circuit and an operational amplifier that inputs the difference between the detected voltage of the motor potentiometer and the set voltage with respect to an intermediate reference voltage of the reference voltage generation circuit to the window comparator In the above, the power supply voltage of the reference voltage generating circuit is a variable voltage proportional to the power supply voltage of the control DC motor.

(Embodiment) FIGS. 1 to 3 show an embodiment of the present invention, in which 1 is a motor, 2 is a motor potentiometer, 3 is a motor driver, and 4 and 5 are comparators constituting a window comparator. , 6 divides the voltage Vcc with a resistor and divides the reference voltage Va, V
Reference voltage generating circuit for obtaining b, Vc, 7 is an operational amplifier for amplifying by taking the difference voltage between the set voltage Via and the detection voltage Vib with reference to the reference voltage Vc, and its circuit configuration is the same as the conventional one (Fig. 5). It is almost the same.

The present invention differs from the prior art in that the power supply voltage Vcc of the reference voltage generating circuit 6 is a variable voltage proportional to the power supply voltage of the motor 1.

That is, the reference voltages Va, Vb, Vc of the reference voltage generating circuit 6 are the second
As shown in the figure, it gradually increases as the motor power supply voltage rises.

Next, the operation will be described. The power supply voltage Vcc of the reference voltage generating circuit 6 changes in proportion to the motor power supply voltage, and thus the reference voltages Va, Vb, Vc also change. As a result, as shown in FIG. 3, the dead zone (between the reference voltages Va and Vb) of the window comparator composed of the comparators 4 and 5 is the motor power supply voltage Vm ₁ , Vm ₂ ,
It depends on Vm ₃ (Vm ₃ > Vm ₂ > Vm ₁ ). That is, the dead band becomes wider as the motor power supply voltage becomes higher. Therefore, even if the motor power supply voltage rises and the torque becomes large, the dead zone is widened at that time, and abnormal control operations that exceed the dead zone are avoided, and the motor may enter the continuous lock state. To be prevented.

Note that overvoltage protection can be achieved by using, for example, a power supply having a voltage stabilizing circuit having the configuration shown in FIG. 4 as the power supply unit so that the input voltage becomes a constant voltage when the input voltage exceeds a certain value. The stabilizing circuit has a configuration in which a series circuit of a resistor 12 and a zener diode 13 is connected between the collector of the transistor 11 and the ground, and the connection point of the resistor 12 and the zener diode 13 is connected as a base, and the input voltage is When the voltage exceeds the zener voltage of the zener diode 13, the voltage of the emitter of the transistor 11 becomes constant.

As described above, according to the present invention, the power supply voltage of the reference voltage generating circuit is a variable voltage proportional to the motor power supply voltage.
When the motor power supply voltage is high and the torque is large, the dead zone of the comparator is wide, and the reverse rotation control signal is input beyond the dead zone to prevent a situation where the motor is in the continuous lock state.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a DC motor control device according to the present invention, FIG. 2 is a characteristic diagram showing a relationship between a motor power supply voltage and each reference voltage in the embodiment, and FIG. FIG. 4 is a characteristic diagram showing the relationship between the detected voltage of the motor potentiometer and the motor angular velocity using the motor power supply voltage as a parameter, FIG. 4 is a circuit diagram of a constant voltage power supply used for overvoltage protection, and FIG. 5 is a conventional control. It is a circuit diagram which shows the structure of an apparatus. 1 ... DC motor for control, 2 ... Motor potentiometer, 3 ... Motor driver, 4 and 5 ... Comparator, 6
...... Reference voltage generation circuit, 7 …… Operational amplifier, Va, Vb and V
c ... Reference voltage, Vcc ... Power supply voltage of reference voltage generation circuit 6.

Claims (1)

[Scope of utility model registration request] 1. A motor potentiometer interlocked with a control DC motor, a motor driver for supplying drive power to the control DC motor, and a dead zone between two reference voltages, and the motor when the input is above and below the dead zone. A window comparator for giving a reverse or forward control signal to the driver, a reference voltage generating circuit for generating two reference voltages of the window comparator and a reference voltage in the middle by voltage division by a resistor, and the motor potentiometer. In the controller of the DC motor, which is provided with an operational amplifier which takes the difference between the detected voltage and the set voltage with reference to the intermediate reference voltage of the reference voltage generation circuit, and which inputs the difference to the window comparator, A direct current motor characterized in that the power source voltage is a variable voltage proportional to the power source voltage of the control DC motor. Other control devices.