Family of Enhanced ZCS Single-Stage Single-Phase Isolated AC-DC Converter for High-Power High-Voltage DC Supply

AC-DC power supply is essential equipment which builds the connection between the ac grid and the dc loads. In order to achieve high-power density and high efficiency, a family of enhanced zero-current-switched (ZCS) single-stage single-phase isolated ac-dc converters is proposed for high-power high-voltage dc application. Only one resonant capacitor is required for the proposed converters to realize ZCS operation. On the other hand, the over voltage problem which exists in former developed ZCS ac-dc topologies is eliminated. Thus, lower voltage rating IGBTs can be applied. Higher efficiency is realized. At the same time, these converters inherit the feature such as one-stage power conversion, low conduction loss, good total harmonics distortion performance, etc. A 3 kW prototype is built to verify the proposed converters. A comparison is made to show the efficiency improvement clearly.