JPS6051484A - Controller for motor - Google Patents

Abstract

PURPOSE:To stabilize the phase of synchronously detecting the variation in a speed command by controlling a servo circuit by the output of a phase comparator, and controlling a motor by the combination of the output and an output from a pulse signal for instructing the speed. CONSTITUTION:A pulse signal 1 for instructing the speed of a motor 7 and a pulse signal of a frequency generator FG8 are compared by a phase comparator 2, a signal of the FG8 is applied to a servo circuit 4 to obtain a DC output by holding a sample, the slope of a sample holding sawtooth wave voltage of the servo circuit 4 is controlled by the comparator 2, and inputted to a composite circuit 5. On the other hand, the speed command 1 is applied through an F/V converter 13 to the composite circuit 5, and the motor 7 is controlled by the composite output. Accordingly, the gains of the comparator 2 and the servo circuit 4 are varied corresponding to the variation in the pulse frequency of the speed command, thereby stably controlling the synchronous rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor control device, particularly a phase-locked loop system (
p, r, , r, system) This relates to improvement of the control device.

FIG. 1 (IL) shows a conventional DC motor control device. In such a control device, speed command pulse 2 is input from terminal 1.
-1 to one terminal of the phase comparator circuit 2, and the output of a frequency generator (FG) 8 directly connected to the motor 7 is applied as a pulse 2-2.
The output pulse 2-3 which is proportional to the phase difference angle is obtained by converting it to the other terminal of the comparator circuit 2, comparing the phase angles of both pulses, and outputting the output pulse 2-3 which is proportional to the phase difference angle. and sends it to the synthesis circuit 5 as a DC level.

The time chart of the input and output signals in the phase comparison plane $2 is as shown in FIG. 1(b).

To explain in more detail the operation of each part of the circuit shown in FIG. 1(,), in the phase comparator circuit 2, as shown in the timing chart shown in FIG. When the detection pulse 2-2 arrives a little later, the output pulse 2-3 of the comparator circuit 2 [0 level output pulse tonnage pulse 2-3 after the arrival of the pulse 2-1 until the arrival of the pulse 2-2] Even if pulse 1 and pulse 2-2 arrive at the same time, it will be at zero level (high impedance).If pulse 2-2 arrives before the arrival of pulse 2-1, the output pulse of comparator circuit 2 will be at ←) level. The output is

Therefore, if the output pulses 2-3 of the comparator circuit 2 are at (G) level and high impedance, the phase of the motor 70 is either ahead of or coincides with the command pulse.
Since there is no need for electric power to accelerate
In the case of level, the phase of the motor 7 is behind the command pulse, so electric power is required to accelerate the motor 7.The output is output from the integrating circuit j83 and the motor 7 is accelerated via the power amplifier 6. It is working. In other words, if the phase of the GL motor 7 lags behind the speed command pulse 2-1, it operates to supply accelerating power to the electric motor 7, allowing extremely high precision control. There is a drawback that if the speed deviates from the speed command pulse (taxed), the control function is lost, so in order to compensate for this drawback, F
The control of the G servo circuit 4 is used in parallel.

In the FG servo circuit 4, as shown in the timing chart of FIG. 1(c), the sawtooth wave 4-3 generated according to the reference pulse 4-2 is converted into a pulse 4-1 obtained by shaping the output of the FG 8.
sample and hold to create output 4-4, and output this output 4-4 as the output of FG servo circuit 4 to synthesis circuit
In addition, it is compared with the output of the phase comparator circuit 2 taken out via the integrating circuit 3, and operates to drive the electric motor 7 via the power amplifier 6 with this comparison output.

In the FG servo circuit 4, the output when the sampling time of the pulse 4-1 of FG8 with respect to the sawtooth wave 4-3 is approximately at the midpoint of the 9...1 side of the sawtooth is set as the midpoint, and sampling is performed earlier than this point. If the speed is ahead, a voltage higher than the midpoint will be held, and conversely, if the speed is lagging, a voltage lower than the midpoint will be held because the speed is lagging. If it is low, the drive output is compared with a reference value and sent to the synthesis circuit 5. Therefore, when the motor speed is far behind the command speed as at startup, the sawtooth wave 4-3 (1: sampled and held output of the FG servo circuit 4 becomes the lowest value, and the output of the synthesis circuit 5 becomes the electric power The motor 7 is accelerated at maximum output via the amplifier 6, and when the motor 7 reaches the command speed, it is controlled by the composite output of the output of the FG servo circuit 4 and the output of the phase comparator circuit 2, and the motor 7 reaches the speed command. ) (It will rotate in synchronization with Luz 2-1 and become 2.

In order for the circuit illustrated in FIG. 1(1) to operate well, there is a restriction that the frequency of the speed command pulse 2-1 and the reference pulse 4-2 of the FG servo circuit 40 must be the same frequency. This is because the frequency of FG8 is commonly used by both the phase comparator circuit 2 and the FG servo circuit 4. Therefore, when changing the frequency of the speed command pulse 2-1 to change the speed of the motor, it is also necessary to change the frequency of the sawtooth wave of the FG servo circuit 4. Currently, such usage conditions are increasing, and for example, in systems that drive magnetic desks for computers, the rotation speed of the disk must be changed when recording at the outer and inner positions in order to increase the disk's recording density. , that is, when storing information, the circumferential speed of the track is
Systems have been developed to ensure a constant value for every track. In this case, it is necessary to set the speed of the spindle for each track, and although it is easy to set the speed command pulse, it is not easy to change the sawtooth waveform of the FG servo circuit 4.

In other words, if the frequency of the speed command pulse is changed in a motor system operating at a synchronous speed with respect to the current speed command pulse, the distribution of the gain of the phase comparator circuit 2 and the gain of the FG servo circuit 4 will not be appropriate, resulting in instability. The speed cannot be changed simply by changing the frequency of the speed command pulse.

The purpose of the present invention is to provide a P, L, L control type electric motor control device that solves the problems in the above-mentioned prior art and makes it possible to significantly change the electric fl II machine speed simply by changing the frequency of the speed command pulse. There is something to do.

The motor control device of the present invention includes a phase comparison circuit that compares the phase difference between a pulse IK commanding the speed of the motor and a pulse signal corresponding to the speed of the motor, and a sample-holding of the pulse signal corresponding to the speed of the motor. a servo circuit that obtains a DC output proportional to the speed of the motor; a circuit that uses the output of the phase comparator circuit to control the slope of the sawtooth wave voltage for the sample bold of the servo circuit; and a circuit that receives a pulse signal that commands the speed. , a power conversion circuit that outputs a DC voltage proportional to the frequency of the pulse signal, and the output voltage of the F/v'A conversion circuit and the output of the servo circuit that obtains an output proportional to the motor speed. The feature is that the electric motor is controlled by the combined output.

The present invention will be explained in detail below with reference to the drawings.

Figure 2 shows an embodiment of the X-motor control device for the blade,
The same parts as in FIG.

In the present invention, the speed command pulse is shaped into a regular pulse via the waveform shaping circuit 11, and then added to the set terminal of the phase comparator circuit 20, and the reset terminal of the comparator circuit 2 is connected to an FG8.
The output is shaped into a regular pulse via the waveform shaping circuit 4-1, and then applied to the FG servo circuit 4.

In addition, the output of the phase comparison circuit 2 is connected to the input terminal of the sawtooth wave generation circuit (not shown) of the FG servo circuit 4 in the time constant circuit 12.
The output of the FG servo circuit 4 is applied to one input terminal of the synthesis circuit 5, and the output of the waveform shaping circuit 11 is converted by the target conversion circuit 13 into a DC voltage proportional to the frequency of the speed command pulse. This is added to the other input terminal of the synthesizing circuit 5, and the electric motor 7 is driven by the synthesized output via the power amplifier 6.

The operation of the FG servo circuit section and the section that obtains the fC DC voltage proportional to the speed command pulse, which are the characteristic parts of the device u of the present invention, will be described in detail below.

Figure 3 shows the output terminal of the phase comparison circuit 2 and the FG servo circuit 4.
A time constant circuit 12 inserted in between is shown, where Q is a transistor, C and R1+R2 are time constant circuits that determine the slope of a sawtooth wave of a sawtooth wave generation circuit (not shown) in the FG servo circuit 4. . If the output of the phase comparison circuit 2 is now at zero level, the transistor Q is turned off and the resistance of the time constant circuit 12 is R.
, 0R8, and when the output level of the phase comparator circuit 2 is H level, the transistor Q is turned on.The resistance of the time constant circuit 12 is only R8, so the time constant is lower than when the output level of the comparator circuit 2 is zero. becomes shorter, and the sampling frequency within the FG servo circuit 4 becomes higher. The output of the phase comparator circuit 2 is a pulse output proportional to the phase difference between the speed command pulse and the FG output pulse, so the time that the transistor Q is ON increases in proportion to the phase difference, and the time constant of the sawtooth wave increases. If the reference timing is short and the reference timing is short, the motor is accelerated in synchronization with this frequency, and the motor operates at a speed synchronized with the speed command pulse.

The output of the one-sided conversion circuit 13 becomes an output proportional to the frequency of the speed command pulse, and the input of the power amplifier 6 becomes proportional to the command speed.

As described above, the motor control device of the present invention changes the respective gains of the phase comparator circuit and the FG servo circuit in response to changes in the frequency of the speed command pulse, and automatically adapts to the frequency of the speed command pulse. Since the adjustment is made to match the operating conditions, the phase of synchronous detection is always in a stable state, and there is a great advantage that stable synchronous rotation control can be performed even if the speed command pulse changes greatly.

[Brief explanation of the drawing]

FIG. 1(a) is a circuit diagram of a conventional motor control device, FIG. 1(b) + (c) is a signal timing chart of its phase comparator circuit and FG servo circuit, respectively, and FIG. 2 is a circuit diagram of the device of the present invention. 3 are explanatory diagrams of a time constant circuit inserted between the phase comparator circuit and the FG servo circuit. 1...Terminal, 2...Phase comparison circuit, 2-1...Speed command pulse, 2-2...Speed detection pulse, 2-3...
... Output pulse, 3... Integrating circuit, 4... FG servo circuit, 4-1... Pulse, 4-2... Reference pulse, 4-3... Sawtooth wave, 4-4 ...output, 5...
Synthesis circuit, 6... Power amplifier, 7... Electric motor, 8.
... Frequency generator (FG), 7'//11... Waveform shaping circuit, 12... Time constant circuit, 13... All conversion circuits. 510- Dimension Dimension Dimension

Claims (1)

[Claims] a phase comparison circuit that compares the phase difference between a pulse signal that commands the speed of the electric motor and a pulse signal that corresponds to the speed of the electric motor;
A servo circuit that samples and holds a pulse signal corresponding to the speed of the motor to obtain a DC output proportional to the motor speed, and the output of the phase comparison circuit controls the slope of the sawtooth wave voltage for sample and hold of the servo circuit. and an F/v conversion circuit that receives a pulse signal that commands the speed and outputs a DC voltage proportional to the frequency of the pulse signal, and the output voltage of the nuclear conversion circuit is proportional to the motor speed. A motor control device characterized in that an electric motor is controlled by a combined output with an output of a servo circuit that obtains the output.