Switching regulator using a high step-up voltage converter for fuel-cell modules

A typical fuel-cell stack produces a low DC voltage with wide variations; therefore a DC-DC switching converter is required to step up and regulate the output voltage. In this work, a model based on electrical variables is developed for a fuel-cell stack. This model is later combined with the model of a high step-up voltage converter to obtain a combined model that incorporates the behaviour of fuel-cell stack. The resulting model is then used to design an average-current mode controller for a switching regulator. To test the proposed regulator, a power module with polymer electrolyte membrane fuel cells is used as an input source. This module delivers an output voltage between 26 and 42 V depending on the current being drawn. Experimental results exhibit the robustness of the switching regulator to step changes in the output load and the output voltage of the fuel-cell stack.