Soft-Switching Single-Stage Power Factor Correction Converter

1 This work is supported by NASA-STTR grant # NAS10-00005 AbstractA single-stage, ZVT-PWM, power factor correction converter is proposed in this paper. Zero-voltage switching for the main switch and zero-current switching for the auxiliary switch are realized by utilizing the leakage inductance of the output transformer and the capacitance of the switches. As a result, no additional resonant components need to be added. ZVS operation is realized for wide range of load and line. High frequency operation of the proposed converter makes the ac-dc power supply possible to be minimized in size and weight and the soft switching scheme will reduce the electromagnetic interference (EMI). The proposed converter uses a grounded auxiliary switch so that the isolated driving circuit is not required. The simplified driving circuitry again improves the overall efficiency and power density. Practically, the direct driving schemes of both the main and the auxiliary switches allows the proposed converter to operate in even high switching frequency and have good regulation capability. A 50-W 500-kHz prototype has been built in the laboratory to experimentally verify the analysis and simulation results.