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

Abstract

Fuel cell is one of the renewable energy sourcesused extensively in stand-alone as well as grid tied applications.Fuel cell provides a low voltage and high current DC outputwhich has to be properly conditioned according to the demandof load. Therefore, a power conditioning unit (PCU) is essentialfor processing the unregulated DC voltage. The PCU possesdifferent dynamics from the fuel cell, so proper modeling of fuelcell as well as PCU is essential. Tight voltage regulation of thepower converters used in PCU is also necessary, so that regulatedpower can be provided to sophisticated load. The transient stateperformance and recovery time during load changes has to bevery small. This paper focuses on the application of synchronousbuck converter which provides low voltage output for differentappliance of electric vehicle. Synchronous buck converter is usedbecause of its low losses. A digital compensator is used to controlthe voltage during sudden changes in load profile. Simulationstudies are performed to study the transient state performanceof the converter.