Zero-cross trigger circuit based on bidirectional thyristor

Abstract

The invention discloses a zero-crossing triggering circuit based on a bidirectional silicon-controlled switch, including an input end for obtaining voltages signals of two ends of a silicon-controlled switch, and an output end for sending a zero-crossing triggering signal to the silicon-controlled switch, wherein a bridge type circuit for performing full-wave rectification on the voltages signals of two ends of the silicon-controlled switch, a first optocoupler for feeding the voltage signals back to a CPU (Central Processing Unit), a second optocoupler for performing level conversion on the voltages signals of two ends of the silicon-controlled switch to generate a corresponding preliminary zero-crossing pulse signal, a comparison amplifier for generating a silicon-controlled zero crossing point triggering signal, a gating element for performing AND on the zero crossing point triggering signal and a capacitor switch triggering signal sent by a process tuning CPU, and a driver for generating a silicon-controlled zero-crossing trigger driving signal are sequentially arranged between the input end and the output end. According to the zero-crossing triggering circuit, the silicon-controlled switch can be turned on by generating the triggering signals at the voltage zero crossing points of two ends of the bidirectional silicon-controlled switch; and the tuning transition process of a system can be stably completed by switching a capacitor in a system tuning process.

Description

technical field [0001] The invention relates to a reactive power compensation circuit of a power system, in particular to a zero-crossing trigger circuit based on a bidirectional thyristor. Background technique [0002] Due to the sudden change of the voltage across the capacitor, inrush current and a series of harmonics will be generated. In the current trigger circuit based on the triac capacitive (TSC) arc suppressing coil, the method of suppressing the inrush current and harmonics at the moment of capacitor switching through the series reactor, that is, at the moment of system switching capacitor tuning, through The series reactor increases the reactance rate to suppress the inrush current and the corresponding harmonics generated by the capacitor, so that the capacity of the arc suppressing coil to compensate the switching capacitor is correspondingly reduced. This compensation method has high device cost, large noise, and takes up a large volume space. At the same time...

AI Technical Summary

Problems solved by technology

In the current trigger circuit based on the triac capacitive (TSC) arc suppressing coil, the method of suppressing the inrush current and harmonics at the moment of capacitor switching through the series reactor, that is, at the moment of system switching capacitor tuning, through The series reactor increases the reactance rate to suppress the inrush current and the corresponding harmonics generated by the capacitor, so that the capacity of the arc suppressing coil to compensate the switching capacitor is correspondingly reduced. This compensation method has high device cost, large noise, and takes up a large volume space. At the same time, The tuning and compensation device needs to switch on and off the same capacitor again, and set the discharge waiting time. The general waiting time is 3 to 5 minutes

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