A programmable self-adjusting SCR-based AC voltage regulator

Abstract

The objective of the thesis is to simulate, design and implement a smart AC voltage regulator which maintains load voltage of a circuit within a predetermind range. The regulator consists basically of two thyristors, a signal conditioner circuit and an 8-bit microcontroller. The regulator is designed to continuously monitor the output voltage across a load. If the monitored load voltage deviates from the predetermined range, the regulator will adjust the firing angles of the thyristors to cope with the deviation in the load voltage. The regulator was tested with resistive and inductive loads. During the tests, the regulator was able to regulate the flow of current from the supply to the load by manipulation of the firing angles of the thyristors in such a way that the predetermined range is never violated. The accuracy provided by the regulator is quite good (< 5%) from the desirable range. In addition, the regulator provides the flexibility of programming. It also ensures voltage stability, because of its automatic nature and fast response time.