Observer-based output feedback control of a PEM fuel cell system by high-order sliding mode technique

This paper deals with an high-order sliding-mode approach to the observer-based output feedback control of a PEM fuel cell system comprising a compressor, a supply manifold, the fuel-cell stack and the return manifold. The suggested scheme assumes the availability for measurements of readily accessible quantities such as the compressor angular velocity, the load current, and the supply and return manifold pressures. The control task is formulated in term of regulating the oxygen excess ratio (which is estimated by the observer) to a suitable set-point value by using, as adjustable input variable, the compressor supply voltage. The treatment is based on a nonlinear modeling of the PEM fuel cell system under study. Simulations results showing the feasibility and satisfactory performance of the proposed approach are provided.