Coordinated Control of Fuel Cell Air Supply System Using Model Predictive Control

Oxidant (air flow) control is an important aspect of fuel cell reactant control system which is designed to fulfill two purposes: air flow rate control and pressure control. These tasks require coordinated valve operation to reduce pressure variation and stabilize flow rate. In this paper, a nonlinear model describing filling dynamics of the supply and return manifolds is presented. The nonlinear model is then linearized around the stack operating point, based on which a model predictive controller is designed to maintain a constant supply and manifold pressures, as well as a constant pressure on the cathode side. Simulation studies demonstrate the model predictive controller is capable of not only regulating constant pressures during steady state operation, but also substantially reducing pressure variations during transient periods. Simulation also indicates that the control system has good robustness against model uncertainty.