Chopper Circuits for Direct AC/DC Conversion

The feasibility of using chopper circuits in ac supply to provide variable dc output is investigated. The three basic chopper circuits are considered and their input and output characteristics are thoroughly studied for direct ac/dc conversion. The performances of these ac-fed choppers for two types of control, time-ratio control (TRC) and phase-shift control (PSC), are compared. One chopper circuit is found to provide better performance characteristics than the other two choppers. The three ac-fed choppers are tested on experimental models to verfy theoretical predictions.