SU1684873A1 - Device for control over triac - Google Patents

Abstract

The invention relates to electrical engineering and can be used when turning on converters. The purpose of the invention is improving the reliability of the device. The goal is achieved by the fact that when the closure of the closing contact of the key element 12 is closed at an arbitrary time, the unlocking of the triac 1 does not occur, since transistor 6 remains closed. When the polarity of the mains voltage is changed, the transistor 6 is turned off, and the transistor 5 is kept in the open state by charging voltage of the capacitor 14. As a result, the initial unlocking of the triac 1 occurs at zero voltage, which eliminates power surges in transients 2 or more.

Description

fig1

The invention relates to electrical engineering and can be used to turn on transducers with limited surges or in the absence of current surges at the time of switching on (depending on the nature of the load).

The purpose of the invention is to increase the reliability of the device.

FIG. 1 shows a diagram of the device; in fig. 2 is a diagram explaining the operation of the null organ.

The device for controlling the triac 1, connected in series by the converter 2 to the terminals 3 and A of the power supply, contains connected in series the first 5 and second 6 controlled keys connected between the control electrode of the triac 1 and the output of the zero-organ 7, which also through diodes 8 and 9, connected in opposite, connected to the control inputs of keys 5 and 6, the input of the null organ 7 is connected to the output of a voltage divider on resistors 1C and 11, which is connected to terminals 3 and 4, two RC-chains through the closing contact of the key element 12 13, 14 and 15, 16, one terminals of which are connected to the common point of the device and one terminal of resistor 17, the other terminal of which is connected to the reference terminal of the triac 1, the other terminals of the RC chains 13, 14 and 15, 16 are connected respectively to the control inputs of the keys 5 and 6 and through the break contact of the key element 12 are interconnected. A load 19 is connected to the output of converter 2 through a filter capacitor 18. As a switch 5, a field effect transistor with an integrated p-channel, with an induced p-channel, with a control junction and a p-channel can be used. as key 6 - the above transistors with p-channel.

The device works as follows.

The initial state of the circuit: the closing contact 12 is open, and the opening contact is closed, triac 1 is locked. The closure of contact 12 can be at any value of the voltage.m of a positive or negative half-wave at terminal 3. Let the switch-on occur at the time tt (Fig. 2) with a positive half-wave at the input terminal 3 of the device. At the output of the null organ 7, an output voltage of positive polarity appears. The transistor switch 5 is fully opened, and the capacitor 14 is charged to the magnitude of the output voltage. The trigger pulse to the triac does not pass, since the transistor of the switch 6 is closed, therefore, the triac 1 does not open at any value of the source voltage at the moment of switching on. During the transition of the source voltage 1) source and the input voltage of the null organ 7 Uex. through zero (Fig. 2), a negative polarity appears at the output of the null organ, which leads to unlocking the transistor of the switch 6 and charging the capacitor 16 to a voltage of 11V. With

a negative polarity current flows through the control electrode of the triac 1 through a zero-organ output- to the power circuits of the transistors of the keys 5 and 6 — the triac control transition 1 — the resistor 17 the zero-organ housing 7. The triac opens when the source voltage, when the source voltage is close to zero. The filter capacitor 18 begins to charge as the voltage increases according to the law of the sinusoid (it increases almost from zero and almost to the maximum of the source voltage). Then, with each new half-wave of the source voltage, the transistor proceeds mainly

current sub air and capacitor 18 (a small part of the current at the same time branched off into the load).

If the key closes at a negative voltage half-wave at terminal 3, the switch transistor 6 opens first, and the switch transistor 5 opens at the next half-wave, and consequently, shimisto 1. i. the scheme operates in a similar way.

When the closing contact 12 is opened, the device is turned off, and the closed contact opens the circuit to discharge the capacitor 14 and 16, after which the device returns to its original state.

Technical and economic advantages of the invention lies in the fact that the device eliminates the transient in the converter due to the first inclusion

the triac at the time of the zero across voltage, which eliminates the harmful current surges resulting from the transition process. This increases the reliability of both the device and the converter.

Claims (1)

Invention Formula A device for controlling a triac with a reference output connected in series with a load, containing a first control key, the input of which is connected to the anode of the first diode and cathode of the second diode, the output to the input of the second control key, the output of which is intended to be connected to the control electrode a triac, a limiting resistor, and t-kicking so that, in order to increase reliability, two RC-chains, a key element with closing and opening contacts, a resistive voltage divider and a zero-organ, are introduced, and the resistive voltage divider through the key contact element is designed to connect to the mains, the resistive voltage divider is connected to the input of the zero-organ, the output of which is connected to the input of the first control key, the cathode of the first diode is connected to the control input of the first 0 controlled key and one output of the first RC chain; the other output of which is connected to the common point of the device; the anode of the second diode is connected to the control input of the second controlled key, one output of the second RC chain and through the break contact of the key element to one output of the first RC -chain, another output of the second RC-chain is connected to the common point of the device and one output of the limiting resistor, the other output of which is intended to be connected to the reference output of the mmstore. figure 2.