Research on control strategy of PEMFC air supply system for power and efficiency improvement

Proton exchange membrane fuel cell (PEMFC) is considered as a type of clean and efficient energy device. Fuel cell air supply system is a key component to maintaining the system output efficiency. In this paper, a dynamic control model for PEMFC system oxygen excess ratio (OER) management is built, and an OER control strategy is designed based on Fractional-Order PID. An OER control index mapping the relationship between the OER and the optimal net power under different load currents is proposed to improve the output performance of the system. The results show that Fractional-Order PID can achieve high accuracy and fast response real-time OER regulation under the step current in comparison to the traditional PID and Fuzzy PID control. Furthermore, under the dynamic load current of vehicle, the average relative error of OER is 2.81 % under optimal OER control based on Fractional-Order PID and the power generation efficiency of the PEMFC system can be increased to 52.55 %.