Design, Simulation and Implementation of Current Fed Isolated Full Bridge DC-DC with Voltage Multiplier for Fuel Cell Grid Applications

This paper proposes novel current fed converter full bridge isolated DC-DC converter with voltage multiplier and active clamp circuit for fuel cell grid connected applications. The proposed converter is best suited for fuel cells and their interfacing to utility three phase grid. Active clamp concept introduced on the primary side of isolation transformer to reduce the turn-off voltage spikes of full bridge active devices. Innate soft-switching with elongated range can be achieved in the recommended converter by using the parasitic capacitance of MOSFET switches and leakage inductance of the high frequency transformer. Zero Voltage Switching(ZVS) is achieved for all the primary devices which allow greater switching frequency operation and improvement in over-all efficiency of the converter for utility interface. Cost, size and weight of the converter minimizes for the higher switching operation of the converter. Half-wave Cockcroft-Walton Voltage Multiplier (H-W C-W VM) having minimum number of multiplying stages is used on the secondary side of the designed converter in order toget the required DC-link voltage for three phase utility grid connection. The converter's switching frequency is maintained at 100 KHz. This paper is organized as introduction, steady state operation, simulation results with two different cases i.e. full load and half load conditions and finally, test result validation of a 250 Watt experimental setup with the proposed converter.