A novel AC voltage regulator

This paper describes a new single-phase voltage controller for supplying resistive loads, with two different strategies. Load voltage is varied by controlling the flux linkage of single-phase transformer windings used with the proposed system. The primary of the transformer is connected in series with the load to the AC supply, while the secondary is shunted with a control device. The flux linkage is controlled by using either a pair of thyristor "triacs" (phase controlled) or a MOSFET transistor (AC chopper topology). Simulation analyses of the two proposed methods of control are presented and verified by experimental results in different cases of operation. The advantages of the proposed system are that it is simple, effective, accurate and has low distortion of supply current, smooth regulation of load voltage and low cost. The proposed system can be used in industrial applications such as heaters, lighting control and AC motor drives controls.