High power factor operation of DCM series-parallel resonant converter

This work presents the operating principle, analysis, design, simulation, and experimental results for a high frequency (HF) transformer isolated single stage ac-to-dc series-parallel resonant converter (SPRC) operating on the utility line, in discontinuous current mode (DCM). The equivalent circuit models and the state space analysis of the SPRC in DCM are presented. PROMATLAB software is used to solve the equations and to obtain important design parameters. SPICE3 simulation and experimental results obtained from a 150 W prototype are presented to verify the analysis. High power factor operation (>0.99) with low harmonic distortion (<18%) have been achieved for the entire load range even without active control, in addition to eliminating switching losses.