Processing energy from fuel cell modules using cascade converters

A fuel cell system produces a low DC voltage with wide variations; 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 obtain an AC voltage. In this work, an interface is proposed to connect a fuel cell system to an inverter. This interface consists of a DC-DC switching regulator using a three-stage cascade boost converter and an average current-mode controller. The proposed converter provides a high step-up conversion voltage ratio. The switching regulator is tested using a power module, which uses polymer electrolyte membrane fuel cells. This module delivers an output voltage between 26 V to 42 V. Experimental results verify the well-known benefits of current-mode control. The proposed control scheme can be easily implemented using a minimum number of IC elements; therefore, it is cost effective for a practical application.