Integrated Modeling and Variable Universe Fuzzy Control of a Hydrogen-Air Fuel Cell System

This paper deals with the problem of integrated modeling and control of a hydrogen-air fuel cell system with a DC-DC buck converter. Unlike hydrogen-oxygen fuel cells, the hydrogen-air fuel cell needs to consider the effect of the nitrogen and the water vapor to the system. Thus, the modeling of process becomes more complex. This paper focuses on a 1KW PEM fuel cell unit and develops the models of stack voltage, cathode flow, anode flow and DC-DC converter based on the mass conservation, Henry law, Dalton partial pressure law, ideal gas equation and electrochemical theory etc. According to the changes of the current of load and the polarization curve at the operational temperature, the stack output voltage can be controlled to a given value by using a variable universe fuzzy controller. Then a DC/DC buck converter is implemented to convert the stack output voltage to a standard 12V DC which can be used as a standard electric source for DC load.