A novel single-phase soft-switching AC/AC converter

A novel single-phase soft-switching AC/AC converter using a simple auxiliary resonant unit and a small AC capacitor is proposed. All main switching devices operate at zero-voltage-switching (ZVS) turn-on, while the auxiliary switches operate at zero-current-switching (ZCS) turn-off. The advantages of this topology are found in efficiency improvement, reduced the voltage stresses, and greatly reduced EMI. Moreover, the proposed AC/AC converter achieves a unity power factor and a sinusoidal input current under linear load. Using a small ac capacitor, instead of a large electrolytic capacitor on the dc-link, increases the lifetime of the converter and reduces its size. Finally, some simulation results are presented for demonstration.