Model Predictive Control for Starvation Prevention in a Hybrid Fuel Cell System1

When current is drawn from a fuel cell, it is critical that the reacted oxygen is replenished rapidly by the air supply system to avoid stack starvation and damage. We first explain that in a stand-alone fuel cell, there is lack of control authority in avoiding excessive oxygen starvation during high current demand. In the hybrid configuration introduced in this paper, a small auxiliary power source significantly extends the control authority in avoiding oxygen starvation. To achieve best possible results without violating operational constraints of the system, a well-devised current split strategy is required. We formulate distribution of current demand between the fuel cell and the auxiliary source in a constrained optimization (model predictive control) framework. As a result, the reactant deficit during sudden increases in stack power was reduced from 50% in stand-alone architecture to less than 1% in the hybrid configuration.