KR900003467Y1 - Arrangement for starting electric motor - Google Patents

Abstract

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Description

Instantaneous power failure restart circuit of induction motor

1 is a block diagram of the present invention.

Figure 2 is an embodiment of the present invention.

3 is an input / output waveform diagram of the main part of FIG.

* Explanation of symbols for main parts of the drawings

A: rectification smoothing part B: allowable voltage detecting part

2: residual voltage detector 3: instantaneous power failure detector

4 latch portion 5 comparison unit

6: Clock pulse generator 7: Microcomputer

The present invention relates to an instantaneous power failure retries circuit of an induction motor. In particular, the present invention detects whether the residual voltage caused by the stored energy of the induction motor is within an allowable value, and detects when a power supply is interrupted while operating an induction motor. When the induction motor is automatically operated.

In general, there has been a conventional circuit in which the induction motor is normally operated when the power supply is interrupted during the operation of the induction motor, and the power is restored automatically when the power is restored. Induction motor variable speed control device is to control the bar, there was a disadvantage that can not operate the induction motor efficiently.

Therefore, the purpose of the present invention is to operate a circuit that efficiently restarts the inverter by controlling the induction motor only when the residual voltage is within the allowable value without driving the induction motor variable speed controller even when the instantaneous power failure is restored when the residual voltage remaining in the induction motor is higher than the allowable value. In providing.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram according to the present invention, after rectifying and smoothing the residual voltage due to the stored energy of the induction motor, and determining whether the voltage is within the allowable value set by the user, and outputting the determined interval. And instantaneous power failure detection unit 3 for detecting whether the instantaneous power failure voltage is returned within a predetermined time, and instantaneous power failure is constant when power is restored within a predetermined time and when a clock pulse is generated in a predetermined clock pulse generator 6. The latch unit 4 for controlling the timer IC used as a means for detecting recovery within a time period, and the comparison unit 5 for comparing the output of the latch unit 4 with the output of the current voltage detector 2. It consists of a click pulse generator 6 which generates a clock pulse by an output and resets the microcomputer 7 which is an induction motor variable speed control device. The basic outline is as shown in FIG.

In addition, the residual voltage detection unit 2 determines whether the rectification smoothing unit A rectifies and smoothes the residual voltage by the accumulated energy of the induction motor, and whether the output voltage of the rectifying smoothing unit A is within the allowable voltage set by the user. It is comprised by the allowable voltage detection part B to discriminate.

2 is a detailed circuit diagram of FIG. 1 according to the present invention. The residual voltage detection unit 2 includes a rectifier smoothing unit A of the residual voltage of an induction motor consisting of a capacitor 1 and diodes D1-D2, and a diode D1-1. Resistors Rl-R2, R4, zener diodes ZD, and variable resistors VR1 to adjust the allowable values of the voltages output from the residual voltage sensing section 1 consisting of D4) and a capacitor C1 as desired by the user. ), An operational voltage detector P1, a photoelectric sensor PC1, a capacitor C2, and the like.

In addition, the instantaneous power failure detection unit 3 includes resistors R15-R2O, R22-R23, R106.R201, variable resistors VR2, capacitors C4 and C55, operational amplifiers OP4 output during power failure and recovery, The output signal of the operational amplifier OP4 includes a transistor Q1 for inputting a power-on state to a timer IC for setting the instantaneous power failure time, the backflow prevention diodes D8 and D9, and the like.

The latch unit 4 resets the above-described timer IC when the power is restored within the set time, and resets the timer IC when the pulse is generated by the clock pulse generator 6. , Q3), a differential circuit composed of a capacitor (C6), a resistor (R29), and a resistor (R25-R28).

The comparison unit 5 compares the output voltage of the allowable voltage adjusting unit 2 with a predetermined reference voltage according to the operation of the latch unit 4 and the reference voltage generating resistors R16 and R17 and the operational amplifier OP2. It consists of diodes D5 and D7 and resistors R5 and R8.

The clock pulse generator 6 receives the output of the comparator 5 to generate a clock pulse and applies it to the microcomputer 7 and the latch unit 4 to the differential circuit by the capacitor C3 and the resistors R9 and R10. And the operational amplifier OP3, the resistors R10-Rl2 and R202, and the diode D6.

3 is an operational waveform diagram of FIG. 2 according to the present invention.

Hereinafter, embodiments of the present invention having the above configuration will be described in detail with reference to the accompanying drawings.

When the power applied to the induction motor is instantaneous power failure, the low level is maintained in the inverting terminal (-) of the operational amplifier OP4 in the instantaneous power failure detection unit 3 as in the t1-t2 section of FIG. Since it is applied, the output of the operational amplifier OP1 becomes a high signal and instantaneously passes the transistor Q1 through the diode D7 and the resistor R18 through a differential circuit composed of a capacitor C4 and a resistor R7. Warm it up.

When the transistor Q1 is turned on, the waveform as shown in FIG. 3 (b) is inputted to the input terminal IN of the timer IC so that the timer IC recognizes that the power supply is momentarily interrupted.

When the low signal is recognized by the timer IC, the output pulse is determined by the variable resistor VR2, the resistor R20l, and the capacitor C55, and outputs a waveform as shown in FIG.

That is, when 555 is used in the timer IC, when the power is returned during the output period of the low pulse, the transistor Q1 is applied to the inverting terminal (-) of the operational amplifier OP4 in the instantaneous power failure detection unit 3. Since the signal is turned off, the output of the timer IC becomes a high signal and is applied to the base terminal of the transistor Q2 through the resistor R24, the diode D9, and the resistor R25 in order, so that the transistor Q2 is applied. It's warm.

Therefore, the collector terminal voltage of transistor Q2 becomes a low signal as shown in (d) of FIG. 3, resets timer IC, and turns on transistor Q3. Since the waveform as shown in (e) is continuously applied to the base terminal, the timer IC continues the reset state.

On the other hand, when the transistor Q3 is turned on, the collector terminal voltage becomes as shown in FIG. 3 (f) and is inputted to the non-inverting terminal (+) of the operational amplifier OP4, so that the diode D7 in the comparator 5 The cathode of the is connected.

In the above state, the voltage output from the rectifying smoother A detecting the residual voltage of the induction motor is determined by the variable resistor VR and the resistor R1 selected by the user, thereby inverting the operational amplifier OP1. The voltage is applied to the terminal (-) and compared with the reference voltage to be applied to the non-inverting terminal (+).

That is, when the reference voltage applied to the non-inverting terminal (+) of the operational amplifier (OP1) is greater than the output of the operational amplifier OP1 is in a low state, the phototransistor (P1) in the photocoupler (PC1) eventually becomes It's warm.

Therefore, the voltage applied to the non-inverting terminal (+) of the operational amplifier OP2 in the comparator 5 becomes a low state and the clock pulse generator 6 cannot be operated.

On the contrary, when the output voltage of the rectifying smoother A is less than the reference voltage, the phototransistor P1 is turned off to the waveform shown in (h) of FIG. 3 and the output of the operational amplifier OP2 is The signal becomes a high signal and is differentiated through the capacitor C3 and the resistor R9 to generate the clock pulse for resetting the output of the operational amplifier OP3 as shown in (i) of FIG. (7), the induction motor is operated normally, and the reset pulse is differentiated through the capacitor C6 and the resistor R29 and applied to the base terminal of the transistor Q2 as a low voltage so as to turn off. The state is maintained so that the circuit of the present invention is in a reoperation state.

The operation and effect of the present invention, which operates as described above, has the advantage of efficiently restarting the induction motor during instantaneous power failure recovery by sensing whether the residual voltage of the induction motor is constant.

Claims (2)

The instantaneous power failure detection unit 3 detects whether the instantaneous power failure voltage is restored within a predetermined time, and latches a detection signal from the instantaneous power failure recovery detection signal of the instantaneous power failure detection unit 3 and restores the instantaneous power failure detection unit 3 when power is restored. A latch unit 4 for resetting the detection time timer of the control unit; a comparison unit 5 for comparing the output of the latch unit 4 and the output of the allowable voltage adjusting unit 2; and the comparison unit 5 An induction motor using a microcomputer 7 having a clock generator 6 for generating a clock by the output of the microcomputer 7 of the induction motor variable speed control device and initializing the latch unit 4. In the instantaneous power failure restarting circuit, the rectified smoothing unit (A) for rectifying and smoothing and outputting the voltages of the predetermined two phases (U, V) to be input, and the output values of the rectified smoothing unit (A) and the reference allowable residual voltage. Tolerance value check that outputs that status when compared with tolerance Unit comes within (B) consists of the induction motor residual voltage tolerances, even if the residual voltage is not completely disappear circuit, characterized in that the microcomputer (7) constituting the remaining voltage detector (2) which operates to set the Li. The method according to claim 1, wherein the allowable value detecting section (B) compares the zener diode means (ZD) with the reference allowable residual voltage set using the direct current limit (OP1) of the rectifying smoothing section (A). When within the allowable value, the instantaneous power failure restart circuit of the induction motor, characterized in that for outputting the output voltage of the comparator means (OP1) by using the photocoupler means (PC1).