Algebraic observer-based output-feedback controller design for a PEM fuel cell air-supply subsystem

Abstract

In this study, an algebraic-observer-based output-feedback controller is proposed for a proton exchange membrane fuel cell (PEMFC) air-supply subsystem, based on both algebraic differentiation and sliding-mode control approaches. The goal of the design is to regulate the oxygen excess ratio (OER) towards its optimal set point value in the PEMFC air-supply subsystem. Hence, an algebraic estimation approach is used to reconstruct the OER based on a robust differentiation method. The proposed observer is known for its finite-time convergence and low computational time compared to other observers presented in the literature. Then, a twisting controller is designed to control the OER by manipulating the compressor motor voltage. The parameters of the twisting controller have been calculated by means of an off-line tuning procedure. The performance of the proposed algebraic-observer-based output-feedback controller is analysed through simulations for different stack-current changes, for parameter uncertainties, and for noise rejection. Results show that the proposed approach properly estimates and regulates the OER in finite-time.