Analysis of a Bridgeless Single Stage PFC based on LLC Resonant Converter for Regulating Output Voltage

Abstract

This paper has analysis a single stage bridgeless power factor correction converter based on a LLC resonant converter. The analysis is taken under DCM condition under the resonant frequency in BOOST region. Operation under DCM condition leads into natural power factor correction, in addition the operation under the resonant frequency leads into zero voltage switching (ZVS) for the MOSFETs and zero current switching (ZCS) for the diodes. The frequency modulation technique is synchronized with pulse width modulation technique in which they are both used in the converter analysis. In addition, the both mentioned techniques have achieved more open wide control degree in system designing in contrary with conventional methods. The converter has been analyzed in three subintervals of the duty-cycle because of DCM mode. This converter was implemented in laboratory by 100 DC volt output voltage and AC input voltage by 200 watt output load.