Model-based control strategies in the dynamic interaction of air supply and fuel cell

Model-based control strategies are utilized to analyse and optimize the transient behaviour of a polymer electrolyte membrane (PEM) fuel cell system consisting of air and fuel supply subsystems, a perfect air/fuel humidifier and a fuel cell stack at constant fuel cell temperature. The model is used to analyse the control of the fuel cell system with respect to maintaining a necessary level of oxygen partial pressure in the cathode during abrupt changes in the current demanded by the user. Maintaining the oxygen partial pressure in the cathode is necessary to prevent short circuit and membrane damage. The results obtained indicate that the oxygen level in the cathode can be successfully maintained through feedforward control of the air compressor motor voltage. However, the net power provided by the fuel cell system is compromised during the transients following abrupt changes in the stack current, suggesting a need for power management via the use of a secondary power source such as a battery.