Design and Implementation of Soft Switched High Gain Current Fed Full Bridge DC-DC Converter for Fuel Cell Applications

Abstract

This paper proposes the analysis and design of new current fed full bridge high gain isolated dc-dc converter for fuel cell application. The proposed converter uses voltage multiplier cells on the secondary side. The objective of the proposed converter is to generate DC link voltage for three phase grid from fuel cell. Current fed Converter reduces the input current ripple at the fuel cell input. The converter utilizes the energy stored in the transformer leakage and parasitic capacitance to maintain zero-current-switching (ZCS) over wide range. Soft switching permits higher switching frequency operation, reducing the size, weight and cost of the magnetic components and improve the converter efficiency. A new design method of half-wave Cockcroft–Walton Voltage Multiplier (H-W C-W VM) that lays on the calculation of the optimal number of stages, which is necessary to produce the desired output voltage with the minimum total capacitance value, is also presented. The operating frequency of the converter is 100kHz. The Analysis, simulation and experimental results of the proposed converter are presented. The proposed converter with three stage voltage multiplier is simulated for two different cases full load and half load conditions and the results were analysed. The hardware model for an input voltage of 30V and input current of 5 Amps was designed, the output from the inverter is 40V and output from the voltage multiplier of three stages is 240V and 0.6 Amps.