Cathode partial pressures estimation of a proton exchange membrane fuel cell for transportation applications

Cathode partial pressures, such as the oxygen partial pressure and nitrogen partial pressure, are important performance parameters of the proton exchange membrane fuel cell. Oxygen partial pressure has a direct influence to the fuel cell output voltage. And the cathode total pressure, mainly composed of oxygen partial pressure, nitrogen partial pressure and vapor partial pressure, has to be kept at the optimal value to ensure the high efficiency of the fuel cell. Therefore, partial pressures are crucial variables which need to be appropriately controled. However, those parameters are usually not measurable. In this paper, an extended state observer, which can effective deal with the nonlinearity and disturbance of the system is proposed. The simulation results show that this observer can accurately estimate the partial pressures.