Robust voltage tracking control for proton exchange membrane fuel cells

This paper presents a robust control approach for proton exchange membrane (PEM) fuel cell systems. In a linear parameter varying system representation of the nonlinear PEM fuel cell dynamics, the system matrices are dependent on the system varying parameters, the output current and the stack temperature. To obtain guaranteed design performance, system uncertainties caused by the variational system parameters are addressed during controller design. The voltage tracking performance is expressed in terms of H-infinity optimization of the ratio of the tracking error to the issued command. The controller is constructed numerically in terms of the convex tractable linear matrix inequalities. Due to the parameter-dependent system matrices of the PEM fuel cells, the formulated matrix inequalities in denoting various design specifications are also dependent on the system varying parameters. Using the affinely dependent property of these matrix inequalities, design performance can be established by evaluating only the matrix inequalities in the extremes of the varying parameters. Both nominal and robust controller designs are verified through time response simulation for both nominal PEM fuel cell and nonlinear PEM fuel cell dynamics. (C) 2012 Elsevier Ltd. All rights reserved.