Sliding-mode-based temperature regulation of a proton exchange membrane fuel cell test bench

The temperature regulation of a cooling system of a PEMFC (Proton Exchange Membrane Fuel Cell) test bench is studied in this paper. Because of the unique configuration which is dedicated for cold start experiments, the operation at nominal temperature is unstable with a simple PI controller. A sliding-based control strategy is applied to suppress the temperature fluctuation. Firstly the structure of the cooling system is demonstrated and the cause of temperature fluctuation is analyzed. Then, a physics-based model of the cooling system is proposed on the Matlab/Simulink platform and validated with experimental data. Based on the model, a Sliding-mode controller with Extended Kalman Filter (EKF) is designed to regulate the temperature. The simulation results showed that the controlled system performed satisfactorily. Furthermore, when applied to the real system, the controller's real-time performance fulfills the test bench criterion. Experimental data show that the coolant temperature at the outlet of the fuel cell stack is kept in a range within ±1 °C, disregarding the heat generated at various working condition.