Air Flow Control in Fuel Cell Systems: An Extremum Seeking Approach

This paper examines the problem of maximizing net power output in a polymer electrolyte membrane (PEM) fuel cell system. The net power production depends heavily on the oxygen excess ratio in the cathode. However, the time-varying parameters and complex nonlinear dynamics of the system present many challenges to regulating oxygen excess ratio under all operating conditions. A constrained extremum seeking control architecture is presented to effectively regulate oxygen excess ratio about an optimum value that maximizes net power output over a broad range or operating conditions. Simulation results demonstrate that this control technique improves fuel cell system performance and our constrained optimization approach enables faster convergence rates for an admissible level or overshoot.