Observer-Based Robust Adaptive Sliding Mode Control for Oxygen Excess Ratio of PEMFC Systems via Improved Time Delay Estimation

Aiming at the estimation and control for oxygen excess ratio (OER) of proton exchange membrane fuel cell system (PEMFC) with external disturbances and unknown uncertainties, a robust adaptive sliding mode control scheme using time delay estimation (TDE) and extended state observer (ESO) is developed, so as to optimize the output performance and durability of PEMFC system. First, an ESO is designed to estimate the unmeasured cathode pressure for the reconstruction of OER. Then, an improved TDE strategy that only uses one-step delay of control input is presented to approximate and compensate the unknown system dynamics. Besides, the adaptive sliding mode control scheme is employed to ensure fast and high-precision convergence of tracking error, in which the switching gain is actively adjusted online by an adaptive law without any prior information. Finally, comparative simulations demonstrate the effectiveness, superiority and robustness of the proposed control scheme.