High-Performance Active-Clamped Isolated SEPIC PFC Converter With SiC Devices and Lossless Diode Clamp

An isolated active-clamped single-ended primary-inductor converter (SEPIC) power factor correction (PFC) converter based on SiC devices is presented. The impact of the resonant inductance on the switch voltage stress and range of zero-voltage switching is analyzed. Analytical expressions for the operating points of the switches over the line cycle are derived and used to evaluate the switching loss. Resonant inductance and snubber capacitance are chosen based on the analysis to reduce the switching loss without overstress of the switches. Lossless diode clamp circuits are designed for the output diode so that the peak voltage and extra losses due to device parasitics-induced oscillation are significantly reduced. The analysis is validated with a 2-kW single-phase PFC rectifier module with a peak efficiency of 96.56% at the 200-kHz switching frequency, total harmonic distortion (THD) < 2%, and power density of 58 W/in
³
.