Fuel-cell energy processing using a quadratic boost converter for high conversion ratios

A fuel-cell stack generates low and unregulated DC output voltage, which depends on the demanded current. Therefore, a DC-DC converter is required to step up and regulate the output voltage. This voltage can be used as an input for an inverter to generate an AC voltage. In this work, a quadratic boost converter with a single active switch is proposed to obtain high conversion ratios and regulated the output voltage. A controller of the switching regulator is designed using average current-mode control approach. Experimental results are shown for a 400 W laboratory prototype to verify the performance of the designed regulator. In this case, a power module with polymer electrolyte membrane (PEM) fuel cell is used as an input source. This module delivers an output voltage between 22 V and 42 V, depending on the demanded current. Load step changes are applied to exhibit the robustness of the switching regulator. Finally, system stability is verified with experimental frequency response analysis.