Design and experimental verification of model-free adaptive sliding controller for air supply system of PEMFCs

The control performance of cathode flow rate and pressure directly determines the efficiency and service life of proton exchange membrane fuel cell vehicles. The mechanism modeling methods are difficult to accurately describe the parameter perturbations and model uncertainties, which leads to the deterioration of the control performance. For this reason, it is of great practical significance to study control methods independent of the mathematical model of the cathode flow rate. The paper investigates a model-free adaptive discrete sliding control strategy for cathode flow rate. First, the nonparametric dynamic linearization technology is used to obtain a cathode flow rate dynamic linearization model, which can realize the adaptability and robustness to internal parameter perturbations and external disturbances of the controlled system; Second, an adaptive second-order discrete sliding mode controller based on the novel data-driven sliding surface is designed to improve the transient quality with smaller steady state errors, and the stability and robustness are theoretically guaranteed. Third, given that the cathode pressure mechanism is described clearly and simply, the backstepping method is applied to control the cathode pressure , and the robustness is proved in the framework of input-to -state stability theory. Finally, the simulation results are given to verify the effectiveness and robustness of the proposed method compared to the benchmark controllers, and the experimental results show that the proposed method can achieve accurate tracking control of cathode flow rate and pressure with excellent response speed.