Hydrogen saving and power improvement for proton exchange membrane fuel cells via optimum stack operating temperature tracking with enhanced performance

Thermal management is one of the most focal tasks to maintain the safe and efficient power generation of proton exchange membrane fuel cell (PEMFC) stack. Due to various disturbances, uncertainties and couplings, the existing PEMFC thermal management strategies mostly exhibit unstable temperature regulation effect, high energy consumption and poor design flexibility. This research proposes innovative contributions to address the above challenges. Firstly, the minimum stack current and the optimum stack operating temperature (SOT) as a function of the net power demand are calibrated simultaneously based on a high-fidelity PEMFC system model. Secondly, an adaptive disturbance observer with preset settling time is developed to exactly counteract the impacts of external disturbances and modeling errors, thus enhancing the control robustness. Thirdly, an enhanced constraint tracking controller is devised to ensure that the SOT and the temperature difference between the stack inlet and outlet track respective setpoints, without violating user-configured constraints regarding regulation time, overshoot and stable accuracy. The simulation results under a hybrid working scenario indicate that the proposed controller exhibits more superiority in optimum SOT tracking and fuel economy improvement, moreover, the gravimetric energy density achieved by the proposed controller is 2.2-5.4% higher than that corresponding to other representative controllers.