Minimum supercapacitor choice to provide current step variation in FC PEM

The adoption of fuel cells for industrial applications, transportations and home power generation has widely increased during recent years. The performance evaluation of a fuel cell system requires both static and dynamic model, especially for the automotive applications which involve step variations of electric load. Besides, current step variations abruptly change the fuel cell voltage causing a non-linear behavior (under-voltages). In this case, a parallel supercapacitor becomes an important element to provide energy during transients. Fuel cell dynamic models presented in literature adopt chemical-physic-electrical parameters that are not usually provided by factories. In this paper, we deal with the implementation of dynamic fuel cell model during step current transients from the electrical point of view [1]. The FC model is used to compute the minimum capacitance of the supercapacitor needed to obtain gradual variations of fuel cell terminal voltage from initial steady state to final steady state values.