A bipolar gain bridgeless set-up AC/DC converter with power factor correction

Abstract

Bipolar gain step-up converter can realize dc output voltage regulation no matter the input voltage is positive or negative. Therefore, bipolar gain step-up converter can be used as bridgeless PFC converter, without using the front-end bridge rectifier. In this paper, a bipolar gain step-up AC/DC converter operating in discontinuous conduction mode (DCM) as bridgeless PFC converter is introduced. Its operating principle in DCM is illustrated, and its steady-state characteristic is analyzed. It is found that the turn-on loss of the switch and the reverse-recovery losses of the diodes are reduced. Furthermore, the voltage gain of this converter is similar to that of conventional boost converter in DCM. Finally, experimental results are provided with a 50W/200V prototype for line voltage of 85~135Vrms to evaluate the performance of the DCM bridgeless PFC converter.