Analysis and Design of Zero-Voltage-Switching Multi-phase AC/DC Converters

In this paper, the generic analysis and design of Zero-Voltage-Switching (ZVS) multi-phase AC/DC converters are proposed. With the Edge Aligned PWM (EA-PWM) scheme, all switches of ZVS multi-phase AC/DC converters can realize ZVS operation. Besides, the switching frequency is fixed and the auxiliary switch only operates once in each switching period. Its operation stages in a switching cycle are analyzed and a generic ZVS condition is derived. Based on the proposed theory, a ZVS two-stage three-phase photovoltaic (PV) inverter is investigated, which is regarded as a 5-phase converter. Its ZVS condition under different working conditions is discussed. Finally, a 10kW prototype with 150kHz switching frequency of the ZVS two-stage three-phase PV inverter is built and the experiment results are given to verify the analysis. In addition, the extension of the ZVS multi-phase converter in different applications is introduced.