JPS6070984A - Control circuit of dc motor - Google Patents

Abstract

PURPOSE:To simplify the circuit configuration by digitally processing together with the digital processing of a motor angle velocity all by a microprocessor. CONSTITUTION:The rotary angle to the target value is set in a counter 7, the counted value is subtracted or added by 1 whenever a tachometer pulse (e) is outputted by the rotation of a motor 4, and the motor rotary angle signal (a) is outputted. A target tachometer period setter 1 outputs a target tachometer period (b) in response to the motor rotary angle signal (b). A pulse width calculator 2 compares the period of the pulse (e) with the target tachometer period, and drives a switching power amplifier 3 in response to the compared result. Thus, all can be digitally processed to simplify the circuit configuration.

Description

[Detailed description of the invention] Subject of invention 15 The present invention is for controlling a DC motor with a tachometer.

Regarding circuits.

Conventional technology Direct current using a conventional switching amplifier.

Input pulse of power amplifier of motor control circuit 2. .

The signal is converted by converting the logic signal into an analog signal using a digital analog converter (DA'C).

sawtooth at a frequency sufficiently higher than that of the analog signal.

The pulse width is controlled by comparing the waveform with the analog signal and the time between high level and low level.

The disadvantage of this conventional method is that it requires a step to convert a logic signal into an analog signal, making the circuit configuration complicated.

OBJECTS OF THE INVENTION 10 An object of the present invention is to provide an inexpensive DC motor control circuit using a switching amplifier.

SUMMARY OF THE INVENTION In the present invention, the input signal of the power amplifier is pulsed using a microprocessor.

Digital processing is performed in the width calculation section, and the DAC is processed.

The road was omitted. Also, the target angular velocity is PRσM.

All digital processing was performed using the microprocessor described above, including the method of recording the motor angular velocity data and using it as sequential data, and the digital processing of the motor angular velocity data.

Embodiments of the Invention The present invention resides in a circuit for controlling a motor to rotate by a desired angle.Fifteen embodiments of the present invention will be explained below with reference to FIGS. 1 to 8. Ma.

First, in FIG. 1, the motor rotation angle signal a gives the rotation angle up to the target as a count value of tacho pulses.

It is a digital signal. The initial value is set in the counter 7, and is subtracted or added by 1 every time 10 tacho pulses are output as the motor rotates.

The initial value has a positive or negative sign depending on the rotation direction of the motor 4.

This is given to the pulse width calculation section 2.

It will be done. The target tacho cycle setting section 1 is a decoding circuit for presetting the tacho pulse cycle which indicates the motor rotational angular velocity, and is a decoding circuit for presetting the tacho pulse cycle which indicates the motor rotational angular velocity.

Consists of two FROMs with bit input and 4-bit output.

The motor rotation angle signal a is used to give the optimum motor angular velocity according to the rotation angle up to the target.

The target tachometer cycle becomes smooth. This is the value of counter 7.

The motor 4 rotates faster as long as .

Control is performed by decreasing the tacho period and slowing down the rotation of the motor as it approaches the target, that is, increasing the tacho period.

Next, the switching power amplifier 3 of FIG. 1 has transistors Q1 to Q4 and diodes D1 to 5 as shown in FIG.
The input signal q2. q
4 are given, pulse width controlled signals ql, qa
turns on Ql or Q3. 1° The pulse width signal C in FIG. 1 is the signal q1 to q4 in FIG.

number, q" + q' is one set, and q21q3
There is one set. When q4 is on, ql is on.

Then, from vCC, it passes through Ql, passes through the motor, and passes through Q4.

A current flows to ground, and q2 is on.

When qa is turned on, a current flows from Vcc through Q3, the motor, and Q2 to ground. these.

The directions of the currents are opposite to each other. of the signal in Figure 4.

In this case, Q4 in Figure 3 is always ON, and Ql is for a certain period of time.

A signal that turns ON and drives the motor in a fixed direction.

3. No. 3. This signal is the motor drive signal d, and therefore the motor rotates with a drive voltage proportional to the time width of the pulse width signal C.

When the motor rotates in FIG. 1, a motor tacho pulse e is output, which becomes the input signal 5 of the pulse width calculation section 2. The pulse width calculation section 2 is microproduced and controlled by a microprocessor, and is composed of a motor-tacho period detection section 8 and an output signal processing section 9, as shown in FIG. It is assumed that the tacho pulse e has a data cycle of 50q6, that is, 1O in which the high period and the low period are equal. The signal is a digital representation of the length of a half cycle.

The motor tacho period detection section 8 is a motor tacho pulse.

It has a function to detect the period of e, and has the function of detecting the period of tacho pulse.

The high and low times are stored in a register 1 as a count value.

FIG. 6 shows the flowchart of 1. That is,.

Kara during that period when the taco pulse is at a high level.

When the count value is low level, the count value for that period is RF
Create it in iGl and move it to RE G1'. 9 in Figure 6. .

・ 4 ・ REGI and RF3 G 1' are microprograms.

You can manage any different registers. next.

Acceleration and deceleration of the motor of the output signal processing unit 9.

The time processing will be explained.

FIG. 7 shows control of deceleration. Note that whether the speed is deceleration or acceleration is 5th speed, the rotation amount has passed halfway through the set rotation amount.

It is determined by the amount of time. From motor 4.

-Receive a signal indicating the rotation direction of Y4 and reverse.

q like passing current through rotation! Or select one of q4. Next, a constant value (1000) of 10 is set in REG4. Target value REG 2' and actual value REG 1'.
For comparison, if the actual measurement is slower, q1 to q4 are set to 0 and no current is passed for a certain period of time. When it's fast, it's speed.

Calculate the difference and apply a reverse current for a period of time proportional to the difference.

and applies the brake to motor 4. 15 FIG. 8 shows acceleration processing. On counter 7.

The direction of rotation is known from the set sign and the machine accelerates.

High level by selecting either direction q2 or q4.

shall be. Check the speed like last time and measure it.

When is fast, q1 to q4 are set to 0, and the current for a certain period of time.

Don't flush. If it is slow, the current flows in a direction that accelerates the time proportional to the difference.

Repeat the process from -E.

According to this embodiment, digital to analog conversion.

No circuit is required, all digital signal processing is possible, and the circuit configuration can be simplified.

Effects of the Invention According to the present invention, since all digital signal processing can be performed, the circuit configuration can be simplified, and the amount of hardware can be reduced by micro1[] program processing, which has the effect of reducing costs.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of motor control, and FIG. 2 is a schematic block diagram of motor control. 3 is a detailed diagram of the target tacho cycle setting section, FIG. 3 is a configuration diagram of the switching power amplifier, FIG. 4 is a diagram showing a detailed example of the pulse 9 width signal C, and FIG. 5 is the configuration of the nose section of the pulse width meter. Figure, 6th
The figure shows the motor tacho cycle detection section. The flowcharts in FIGS. 7 and 8 are output signal processing. Circumferential flowchart. 1...Target tacho cycle setting section 2...Pulse width calculation section 3...Switching power amplifier 4...
・Motor with tacho 6...P ROM 5 8...Motor tach cycle detection section 9...Output signal processing section 0 5 = Go 1'' I ffi 2 Figure 8 ・3 Figure 1 4 Figure O 6 Figure 7 Figure Actual rotation 1''J7 182=1 1-e-1 f? :Ecr4-10θO Ta N upper 2-shaku Ea t= 搏H0 搲I~ N-- 9t=I3=f F? ECr3- t = rEQ3 [phase]

Claims (1)

[Scope of Claim] A control circuit for a DC motor having a tachometer that outputs a tacho pulse at every fixed rotation angle, comprising a target/target tacho cycle setting section that gives a target angular velocity of the motor as a digital signal; ,
A detection circuit that converts the actual tacho period from the tacho pulse into a digital signal and detects it, and the target tacho period setting section. The outputs of the circuits are compared, and according to the comparison result, 1c] the DC current is applied for a time corresponding to the difference between the respective outputs. It is characterized by being equipped with a circuit that drives the motor. DC motor control circuit.