Dynamical Modeling for a Fuel-Cell Based Power Generation System

Fuel-cell stacks are an attractive and efficiently way for power generation; however, its low and unregulated DC output voltage demands a DC-DC conversion stage to step-up the voltage to suitable levels. In this way, a transformerless boost converter with high step-up conversion ratios is proposed in this work to process the energy from a fuel-cell stack. This configuration is formed by two inductors, two active switches, one diode and one output capacitor. Both inductors are charged (simultaneously) in parallel via the active switches, and discharged in series across the diode. The dynamical behavior of the fuel-cell stack connected to the transformerless boost power converter is captured in terms of Kirchhoff voltage and current laws. As a result, a set of mathematical representations for feedback purposes is detailed. Experimental results are shown for a 250 W laboratory prototype to verify the validity of the proposed models.