Investigation on Transient Response of Fuel Cell Power Conditioning Unit during Rapid Load Changes

Fuel cell is one of the renewable energy sources used extensively in stand-alone as well as grid tied applications. Fuel cell provides a low voltage and high current DC output which has to be properly conditioned according to the demand of load. Therefore, a power conditioning unit (PCU) is essential for processing the unregulated DC voltage. The PCU posses different dynamics from the fuel cell, so proper modeling of fuel cell as well as PCU is essential. Tight voltage regulation of the power converters used in PCU is also necessary, so that regulated power can be provided to sophisticated load. The transient state performance and recovery time during load changes has to be very small. This paper focusses on the application of synchronous buck converter which provides low voltage output for different appliance of electric vehicle. Synchronous buck converter is used because of its low losses. A digital compensator is used to control the voltage during sudden changes in load profile. Simulation studies are performed to study the transient state performance of the converter.