There are two important objectives for airflow control in proton exchange membrane fuel cells(PEMFCs). One is to keep the desired excess ratio(to provide sufficient reactant airflow) to ensure fast transient response and to minimize auxiliary power consumption, and the other one is to control the cathode pressure in stack within an acceptable range. In reality, the big inertia of stack's airflow-supplying activator limits the bandwidth of air-flow supply loop, which makes the first objective difficult to achieve, and another difficulty is that airflow is coupled with the cathode pressure in stack, which make it uneasy to keep the pressure unchanged in case of airflow perturbation. In order to overcome these difficulties, three dependant controllers are presented in this paper to control airflow, decouple the cathode pressure in stack from airflow and stabilize the cat hode pressure in stack respectively. The effectiveness of these controllers is proven by subsequent simulation and test results.
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