Improvement of Single-Switch Bridgeless PFC Cuk Converter for Circulating Current Elimination and Components Maximum Current Stress Reduction

Abstract

This paper presents the improvement of single-switch bridgeless PFC Cuk converter for circulating current elimination and maximum current stress reduction on components. On the existing converter structure, circulating current at diodes causes conduction losses and maximum current stress that increase the component size. Therefore, circulating current is eliminated by rearranging the position of input diodes thus the input diodes in which can block the returning path of current through the input inductors. The principle of circulating current elimination is also discussed in detail in this paper. A 100 W converter with output voltage of -48 V has been tested to verify the principle. The results of the experimental hardware show the removal of the circulating current, the maximum current stress in input diodes are reduced from 8 A to 2.8 A and the maximum current stress in input capacitors also reduced from 10.3 A to 6.5 A.