A fuzzy extend state observer-based cascade decoupling controller of air supply for vehicular fuel cell system

Abstract

Appropriate air mass flow and pressure management can not only improve the performance and efficiency of the fuel cell, but also prevent irreversible degradation caused by oxygen starvation and pressure fluctuation. In this paper, a novel observer-based cascade decoupling control schemeis proposed for the air supply subsystem. First, a dynamic fuel cell system model is established and parameterized using an 80-kW fuel cell system experimental dataset. Based on this, an improved extended state observer by fuzzy logic technique is put forward to reconstruct the oxygen excess ratio. In the proposed cascade control, the outer loop is established by the sliding mode controller coupling fuzzy extended state observer to realize oxygen excess ratio tracking, and the inner loop is developed by inverted decoupling controller combining active disturbance rejection control to decouple control air mass flow and cathode supply pressure, where total disturbance comprised model uncertainty and external disturbances can be estimated and compensated. Then, the proposed fuzzy extended state observer is validated and compared with traditional linear extended state observer, and the present results show that the fuzzy operation holds better performance in the presence of initial deviation, noise, and parameter uncertainty. Furthermore, the proposed observer-based cascade decoupling control framework is validated through a series of comparative simulations, and the results confirm the effectiveness and robustness of the proposed scheme in air mass flow and pressure decoupling control, concurrently ensuring that the estimated oxygen excess ratio can track the target value within 1 s.