JPS60237885A - Speed controller of induction motor - Google Patents

Abstract

PURPOSE:To eliminate the deceleration of an induction motor and the flicker of display means by controlling the display means only during specific zone with both an interrupt signal and a zero point detection signal as a reference. CONSTITUTION:When an AC power source voltage becomes zero, a zero point detector 2 outputs a zero point detection signal A. A microcomputer 3 inputs a zero point detection signal A, thereby outputting a control signal C in display means 8 to execute a time division control. A CPU5 obtains the output timing of a firing signal B, and sets a timer beta. When a timer alpha counts the prescribed time, it outputs an interrupt signal F to a CPU5. Accordingly, the CPU5 outputs a control signal C to the means 8 during the zone Y to execute time division control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a speed control device for an induction motor equipped with a display means, and particularly to a speed control device for an induction motor equipped with a display means, in particular, a speed control device for controlling the speed by controlling the firing angle, and further comprising:
The present invention relates to a speed control device for an induction motor that controls the display means using time-division control.

[Prior art]

FIG. 1 shows an example of speed control of an induction motor according to the prior art.

The speed control of an induction motor according to the prior art is based on a point at a predetermined phase based on a zero point detection signal (shown in Figure 1 (B)) generated when the AC power input reaches the zero point as shown in Figure 1 (A). By generating an arc signal (shown in Figure 1 ti) and controlling a thyristor as an ignition means connected to a power supply with this ignition signal, the voltage shown in Figure 1) is supplied to the induction motor. I try to do that.

Such control is normally performed using a Lebel microcomputer, and this microcomputer displays display means for displaying the actual speed, set speed, etc. of the induction motor, for example, the three-digit segment P1. P2. When controlling the display means consisting of p5 in a time division manner, the following problem occurs. That is, in controlling the display means, a timer means outputs an interrupt signal of a constant period as shown in FIG. , X2, and X5. For example, at time X1, a segment with 1 digit P1 is controlled, at time X2, a segment with 2 digits P2 is controlled, and at time X3, a segment with 3 digits P5 is controlled.

However, in conventional speed control, the interrupt signal shown in FIG. 3 (a) K is set independently of the zero point detection signal shown in FIG. 1 (b). Even if the zero point detection signal is output, the microcomputer cannot accept it, and therefore the ignition signal cannot be set, resulting in a reduction in the speed of the induction motor. On the other hand, if the speed of the induction motor is controlled to be constant, flickering will occur on the display means.

[Summary of the invention]

The present invention was made in view of the drawbacks of the prior art in Japan, and
The interval y is based on both the interrupt signal and the zero point detection signal.
By controlling the display means so that the output time of the zero point detection signal does not coincide with the control time of the display means, deceleration of the induction motor and flickering of the display means are eliminated at once. The purpose is to provide a control device.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 4 and 5.

In the figure, 1 is a full-wave rectifier that performs full-wave rectification of the power supply voltage, and 2 is a zero-point detection means that detects the zero point of the full-wave rectified waveform output from the full-wave rectifier 1 and outputs the zero point detection means. A timer, which will be described later, starts operating according to the zero point detection signal A.
A signal F is generated.

3 is a microcomputer as a control means, the microcomputer 3 has a level of interrupt, and an input circuit 4 for A/D converting the zero point detection signal A;
It is composed of a CPU 5, a memory 6, timers α and β, and an output circuit 7 that converts internal signals from D/A and outputs them. The CPU 5 calculates the output time of the ignition signal date based on the set speed of the speed detection signal 1 outputted by a speed detection section (not shown) that measures the actual speed of the induction motor M, and sets the timer β. By inputting the zero point detection signal A or an interrupt signal output from the timer α, which will be described later, a control signal C is output for controlling the display means 8 in a time-division manner over the interval y.

Further, the generation timing of the ignition signal B is set according to the time measured by the timer β. Note that the timer α has a predetermined number (
When the interrupt signal F (3m) in the drawing is interrupted, it has a function as an interrupt operation stopping means that stops the generation of the interrupt signal F thereafter. That is, it takes 4 hours for the CPU 5 to time-divisionally control the display means 8.
A processing time y (shown in FIG. 5 (-→)) of approximately 0 steps is required, and the processing time y is a period in which other signals are prohibited from interrupting. Therefore, the zero point detection signal A (
Even if the signal shown in FIG. 5(b) is output, the microcomputer 3 cannot accept the zero point detection signal A.

Therefore, the timer β is used as an interrupt operation stopping means to stop the interrupt operation after outputting the third interrupt signal F so that the processing time y does not coincide with the output point of the zero point detection signal A, that is, the zero point of the power supply voltage. is also working.

9 is an ignition means connected between the AC power supply 10 and the induction motor M, and the ignition means 9 includes a light emitting device 11 such as a light emitting diode that emits light when the above ignition signal B is input; A light-receiving element 12 such as a phototransistor that induces a pulse voltage when light from the element 11 is input, and the pulse voltage induced by the light-receiving element 12 is input as a gate signal to connect the AC power source 10 and the induction motor M. It is composed of a triac 13 that conducts and interrupts conduction.

Further, the display means 8 is an induction motor M as in the prior art.
It displays the speed, set speed, etc., and is composed of three-digit segments, and is activated by inputting the control signal C mentioned above.

The speed control device for an induction motor according to the present invention is configured as described above, and its operation will be explained next.

First, when the AC power supply voltage becomes zero, the zero point detection circuit 2 outputs the zero point detection signal A.

On the other hand, the microcomputer 3 inputs the zero point detection signal A and outputs a control signal C to the display means 8 to execute time division control. In this case, a process of, for example, 40 steps for time-sharing control continues from time jo to time tl. In this way, since the display means 8 is controlled after waiting for the zero point detection signal A, the signal A is reliably captured. Between times t1 and t2, the CPU 5 performs arithmetic operations to determine the output timing of the ignition signal B and to set the timer β. Therefore, the induction motor is set to a speed according to this calculation result. When the timer α measures a predetermined time t2, the time t2
In order to output the interrupt signal F to C'PU 5, the CPU 5 outputs the control signal C to the display means 8 for only the interval y to execute time-sharing park opening. In this case, the processing for time-sharing control of the display means 8 continues until time t3. Between time t5 and curtain t, the CPU 5 executes a calculation operation to determine the output time of the ignition signal B.

After that, it is assumed that the same time division control as described above is executed and time point tB is reached. However, at time t11, the timer α has counted a predetermined number (3) of interrupt signals and is in a stopped state, so the timer α does not output the interrupt signal F to the CPU 5, and the time division of the CPU 5 to the display means 8 is Control is temporarily suspended. Therefore, when the zero point detection signal A is output at time t91c, this signal A is taken in, so that the same control as at time to described above is executed.

In this way, the output time of the zero point detection signal A does not coincide with the processing time y of the display means 8, and therefore the microcomputer 3 can reliably receive the zero point detection signal A. Therefore, the point of the induction motor M Delays in the output timing of the arc signal B can be prevented and the speed can be maintained at a predetermined level.

Furthermore, since the microcomputer 3 executes the time division control of the display means 80 based on both the zero point detection signal A of the power supply voltage and the interrupt signal F from the timer α, the time division control of the display means 80 may be made longer. This prevents the display means 8 from flickering.

Note that the ignition means 91, the interrupt signal generating means, and the interrupt signal stopping means α are not limited to those of the embodiment, and various other means may be used.

〔Effect of the invention〕

As explained above, according to the present invention, the display means is controlled for a certain period y based on both the interrupt signal and the zero point detection signal output when the AC power supply voltage becomes zero,
Since the phase angle of the ignition signal is set in other sections, it is possible to prevent a delay in the output timing of the ignition signal, and also to prevent flickering of the display means.

Furthermore, if the control of the display means is stopped immediately before the zero point detection signal is generated, it is possible to reliably prevent the zero point detection signal and the interrupt control section from overlapping each other, so that the output timing of the ignition signal can be delayed. This can definitely be prevented.

[Brief explanation of drawings]

Figures 1 and 2 show the speed control of an induction motor according to the prior art, and Figure 1 (a) shows the AC power supply voltage, and Figure 1 (b)
shows the zero point detection signal, Fig. 1←received ignition signal, Fig. 1) shows the voltage applied to the induction motor, Fig. 2 shows the display means consisting of three-digit segments, and Fig. 3 (A) shows the voltage applied to the induction motor. 3 (b) shows the control time of the display means, FIG. 4 shows a circuit configuration diagram of the speed control device for an induction motor according to the present invention, and FIG. 5 shows a timing chart. 2φ@system zero point detection means, 3...-micro combinator (control means), 8... display means, β... timer (
Interrupt signal generation means 2 interrupt operation stop means), A...
Zero point detection signal, F...interrupt signal, M...induction motor. Agent Masuo Osho (and 2 others) Figure 2 Figure 3

Claims (2)

[Claims] (1) An ignition means connected between the induction motor and the power supply, a display means for displaying information related to the operation of the induction motor, a power supply input zero point detection means, and a signal from the zero point detection means as a reference. and control means for generating an ignition signal with a predetermined phase angle to control the ignition means, and interrupt signal generation means for outputting an interrupt signal of a predetermined cycle based on the signal from the zero point detection means, The control means controls the display means for a certain period y based on the interrupt signal from the interrupt signal generation means and the signal from the zero point detection means, and sets the phase angle of the ignition signal at least for a period other than the period y. A speed control device for an induction motor, characterized in that: (2) An ignition means connected between the induction motor and the power supply, a display means for displaying information related to the operation of the induction motor, a human power zero point detection means, and a signal from the zero point detection means as a reference. control means for generating an ignition signal with a predetermined phase angle to control the ignition means; interrupt signal generation means for outputting an interrupt signal of a predetermined period based on the signal from the zero point detection means; and the interrupt signal. Interrupt operation stopping means counts the signal output from the interrupt signal generating means and stops generating the interrupt signal when the count value reaches a set value, and the control means controls the signal from the interrupt signal generating means and zero point. Controlling the display means for a certain period y based on the signal from the detection means, setting at least the phase angle of the ignition signal for a period other than the period y, and controlling the display means immediately before the generation of the zero point detection signal. A speed control device for an induction motor, characterized in that the speed is stopped.