High Efficiency Bridgeless Power Factor Correction Buck Converter for High Frequency AC Systems

This paper presents a bridgeless power factor correction (PFC) buck converter for high frequency AC systems. This PFC converter utilizes series resonant circuit at the AC-side to perform the PFC and buck topology at the DC-side to regulate the output voltage. In order to reduce the number of components and to improve the efficiency of the converter, a bridgeless topology is proposed. A detailed circuit analysis has been done. The AC to DC voltage conversion ratio and boundary of the converter operation are explicitly expressed. Afterwards, experimental results are provided to verify the operation of the topology. The converter prototype operates at 100 kHz with an output power of 10 W. Its efficiency is over 90 %. The total harmonic distortion of the input AC current at full load condition is less than 20 %.