Modeling and Control of Cathode Air Humidity for PEM Fuel Cell Systems

Abstract This paper deals with modeling and control for the humidification process in the cathode of the PEM fuel cell system at high current demand. An improved control oriented model of the humidification process is developed in this paper. We add a pressure factor into the equation of mass transfer to improve the accuracy of the model in the domain of our study. Under an exhaust gas recirculated structure, we combine the model of air supply system with the humidification process model. The effectiveness of this model is validated by simulation results. Based on the model, we analyze the control objectives and divide them into a fast one and a slow one. Finally, a feedforward controller is designed to regulate the humidification process based on the analysis of the control objectives. Simulation results show that while satisfying the current demand, the strategy can improve the performance of the humidifier dramatically without affecting the regulation of the oxygen excess ratio.