Performance analysis and improvement of a proton exchange membrane fuel cell using comprehensive intelligent control

To analyze and improve the performance of proton exchange membrane fuel cell (PEMFC) stack, this paper conducts research in intelligent comprehensive control of the operational parameters, such as the operating temperature, pressure, mass flows of hydrogen and air for the PEMFC stack, current density, the exhaust emission quantity of reactant gas, and humidity of the hydrogen and air/oxygen. A detailed analysis is presented about the factors which affect the performance of PEMFC stack, including the operating temperature and pressure, the activation polarization loss, Ohmic loss, concentration polarization loss and the influences of the leakage loss, gas crossover, internal current, exchange current density, limiting current density, and internal structures of the stack. An intelligent comprehensive control strategy is proposed and applied to a 500 W PEMFC system for an uninterruptible power system with backup PEMFC and battery power sources. The experimental results show that the current-voltage performance for the PEMFC stack has been improved comparing with the normal performance using the conventional PI control.