Constant frequency variable power factor PWM scheme for single phase boost type AC-DC converter

Abstract

A new constant switching frequency control method for single phase boost type ac-dc converters is presented. The duty cycle of operation of the converter switches in each switching period is determined such that the input average current tracks the reference template in a cycle by cycle fashion. The problems encountered in achieving smooth and stable operation and the modifications made to overcome them are discussed. The simulation studies done on the converter controlled with this method which is given the name Predicted (on-time) Equal Charge Criterion (PECC) indicate stable operation. The control complexity in this method is offset by advantages like simplified filter design, ability to operate under different power factors and input current levels. The proposed method is expected to be applicable for three phase converters also.