Fully Soft-Switched Buck–Boost Bridgeless PFC Converters With Single-Magnetic Core

This article proposes new fully soft-switched bridgeless buck–boost power-factor-correction converters using single-magnetic core with capability of realizing positive or negative output voltages. Full zero-voltage switching operation is provided for the main switches independent of the load and grid voltage variations. Also, the proposed converters have common ground and single ended output, which increase power density and alleviates common mode noise. The proposed converters operate under discontinuous conduction mode to shape the input current inherently. A 120 W, 100 kHz laboratory prototype with negative output voltage is implemented to verify the theoretical analysis and the effectiveness of the proposed topologies. The results demonstrate efficiency of 96.2% and total harmonic distortion of 4% at full-load condition.