Zero-crossing trigger control circuit of anti-parallel thyristor split-phase switching capacitor

Abstract

The invention discloses a zero-crossing trigger control circuit of an anti-parallel thyristor split-phase switching capacitor, comprising an input and output signal photoelectric isolation unit, a control processing unit, a zero-crossing detection unit and a drive isolation unit; the input and output signal photoelectric isolation unit is controlled by an external The signal generates a low-level control signal and sends it to the control processing unit; the zero-crossing detection unit detects the voltage at both ends of the thyristor and sends it to the control processing unit; when the voltage at both ends of the thyristor is equal, the control processing unit generates it according to the low-level control signal The driving signal for controlling the start of the thyristor is sent to the driving isolation unit; and when the voltages at both ends of the thyristor are not equal, a stop signal for controlling the closing of the thyristor is generated and sent to the driving isolation unit; the driving isolation unit drives the thyristor to pass through according to the driving signal. Zero triggering, and zero-crossing triggering that stops driving thyristors based on a stop signal. The above zero-crossing trigger control circuit can prevent non-zero-crossing triggering of the thyristor.

Description

technical field [0001] The invention relates to the technical field of reactive power compensation and power quality control, in particular to a zero-crossing trigger control circuit of an anti-parallel thyristor split-phase switching capacitor. Background technique [0002] With the development of social economy and technological progress, the application of a large number of high-power power electronic equipment has caused the lack of large-capacity reactive power in the grid, low power factor, increased voltage and current harmonic content, and unbalanced three-phase voltage, etc., and the power quality has deteriorated. serious. However, the traditional contactor switching capacitor reactive power compensation equipment has been unable to meet the requirements of rapidity, accuracy, economy and reliability of reactive power compensation in the field of low-voltage and high-power reactive power compensation. Therefore, as a more optimal solution, thyristor switched capac...

AI Technical Summary

Problems solved by technology

The core of the thyristor switching capacitor equipment is the thyristor zero-crossing trigger control circuit, and if the zero-crossing signal acquisition is inaccurate and the trigger timing is unreasonable, it will cause the thyristor to trigger non-zero-crossing, which will cause inrush current impact on the power grid, or the trigger pulse is unreasonable , the secondary surge will damage the thyristor module

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