Magnetizing-Inductance-Assisted Extended Range Soft-Switching Three-Phase AC-Link Current-Fed DC/DC Converter for Low DC Voltage Applications

This paper proposes a new design with magnetizing inductance to achieve extended range soft switching of a current-sharing three-phase ac-link active-clamped zero-voltage switching (ZVS) current-fed dc/dc converter for low-voltage dc sources, i.e., battery, fuel cells, etc. The paper explains steady-state operation and presents steady-state analysis and design including magnetizing inductance effect. The proposed converter maintains ZVS of all power semiconductor devices over wide range of load and source voltage. Current sharing results in reduced peak currents and conduction losses. The proposed converter combines the merits of three-phase configuration with zero-current switching of rectifier diodes, making it a competitive topology in the area of power supplies/converters for medium power applications requiring high-voltage amplification ratio. Simulation results using PSIM 9.0 are given to verify the proposed analysis and design. An experimental converter prototype rated at 300 W has been designed, developed, and tested in the laboratory to verify and demonstrate the converter performance over wide variations in input voltage and output power for fuel cell applications.