Active soft switching technique for single phase series capacitive link universal rectifier

Double line frequency pulsating power is a major challenge for single phase inverters and rectifiers. While traditional solution of bulky DC bus capacitor can filter out the inherent double frequency harmonic of single-phase inverters, its physical size and high failure rates are often undesirable, especially for applications that demand small volume and weight, high reliability and efficiency. In this paper a novel soft-switching single-phase AC to DC topology, which absorbs the pulsating power with a small film capacitor, is proposed. This eliminates the need for a bulky DC bus capacitor. The proposed topology uses an active auxiliary structure to achieve soft switching for all switches across the full load range. This lowers the power loss, volume and weight. In this paper simulation results and mathematical analysis are presented. Additionally, the behavior of the proposed rectifier is verified through experimental results.