Air flow rate and pressure control approach for the air supply subsystems in PEMFCs

Simultaneous control of the air flow rate and the cathode pressure plays an essential role in enhancing the performance and prolonging the service life of a polymer electrolyte membrane fuel cell (PEMFC). However, this is challenging to implement in practice due to the high complexity and coupled dynamics of the air supply subsystem in the PEMFC. This work, based on a simplified control-oriented model, puts forward a disturbance-observer-based multi-output feedback control strategy to address the issue of synergistically controlling the air flow rate and cathode pressure. The disturbances (Including humidity, temperature, water vapor, etc.) are estimated through an extended state observer (ESO). The final control law, which takes the disturbances observation into account, is designed through feedback linearization technique. A complex, high-order, nonlinear model is used as the high-fidelity plant in the validation process, and a series of simulations are implemented under different operational conditions. The outcomes show that the proposed control strategy offers a rapid dynamic response, precise steady-state tracking performance, and strong robustness against disturbances and unmodeled dynamics.