Characteristics of a series-parallel resonant converter with capacitive output filter operating on the utility line

The characteristics of a high-frequency transformer isolated series-parallel resonant converter operating on the utility line is presented. This converter uses a capacitive output filter. Variable frequency as well as fixed-frequency (phase-shift) control methods are considered. Based on the available analysis, of the DC-to-DC converter, a design procedure (with a design example) is given. SPICE (and SABER) simulation and experimental results, obtained for the designed converter (rated at 250 W) are presented to verify the theory. It is shown that high line PF with lower total harmonic distortion (compared to conventional rectifier followed by large filter capacitor) can be obtained with the proposed converter