Analysis of Input Current Ripple and Optimum Filter Capacitor for Fuel Cell Based Single Phase Inverter

Abstract

Most singlephase inverters, being sourced by fuel cell stacks (FCSs), subject the stacks to reflected lowfrequency (120 Hz) current ripples that ride on average dc currents. The ripple current impacts the sizing and efficiency of the FCS. As such and typically, a passive or active filter is required at the input of the inverter (or output of the FCS) to mitigate the ripple current. Toward that end, this paper outlines a guideline to choose the optimum size of a passive inputfilter capacitor for a fuelcellbased power system from the standpoints of the overall system energy density and cost. Detailed casespecific simulation results, based on an analytical approach, are provided to illustrate key issues for both unity power factor as well as harmonic loads.