Observer-based Sliding Mode Control for Internal Oxygen Supply of PEM Fuel Cell

The performance and durability of proton exchange membrane fuel cell (PEMFC) system are greatly associated with the oxygen excess rate (OER). However, the strongly nonlinear, coupling with numerous unavailable internal states PEMFC system pose a challenge to the OER control. To address it, this paper proposed an observer-based cascaded sliding mode controller. The cascaded controller is composed of the outer loop for oxygen excess ratio tracking and inner loop for compressor flow rate regulation, providing the accurate and fast control of OER. In addition, an injection term-based nonlinear observer is developed to estimate the unmeasurable states in the solution of control procedure. The comparative simulation with current control strategies is executed, the results demonstrate a more accurate and fast control of proposed method by the enhancement of mean absolute percentage error (MAPE) and regulation time with 5.73% and 6.98s.