---------------------------------------------------------------------***--------------------------------------------------------------AbstractIn recent years, the application of high power isolated bidirectional DC-DC converters has increased in fuel cell vehicles and battery based energy storage systems. The main advantages of fuel cells are clean electricity generation high density current output ability, and high efficiency operation. The fuel cell lacks energy storage capability. So in electric vehicle applications, an auxiliary energy storage device (i.e., lead-acid battery) is always used for a cold start and to absorb the regenerated energy fed back by the electric machine. A bidirectional dc to dc converter is necessary between the energy storage battery and the supply to match the voltage level. The regenerated braking energy can be fed back to store the battery using the DC-DC converter. So here the paper presents an isolated bidirectional DC-DC converter with high conversion ratio which can be used in Fuel cell electric vehicles. The simulation of converter with low voltage of 24 V and high voltage of 200V is done using MATLAB/SIMULINK with fuel cell as the input and BLDC motor as the load.