A single-switch power-factor-corrected converter with reduced repeated power processing

By adding an auxiliary winding in series with the input boost inductor of a discontinuous conduction mode (DCM) boost/flyback single-switch power-factor-corrected converter (SSPC), the storage capacitor voltage and its range of voltage fluctuation under line variations can be reduced while maintaining high power factor. Furthermore, the flyback transformer provides a direct energy transfer path to output to increase the conversion efficiency of the converter. It is also found that the power factor, the storage capacitor voltage and the conversion efficiency are controlled by the inductance ratio between the input boost inductor, the auxiliary winding and the output transformer. This paper presents a detailed analysis of the converter operating in DCM. Experimental results for a 15V/60W prototype with wide input voltage range (90-235V/sub rms/) are given to confirm the theoretical analysis of the converter.