Simulation of transient response is crucial to understand the ability of a fuel cell based power system to respond to a sudden change in the load. Various models for the Direct Methanol Fuel Cell (DMFC) are proposed in literature. However, to the best of the author's knowledge, no electrochemical model of DMFC has been developed which can effectively predict the dynamic response of the fuel cell. In this thesis, an electrochemical model for a DMFC is introduced, which also incorporates the methanol crossover rate, to study the transient response and the load following capability of DMFC. The proposed DMFC system is subjected to a residential load profile to illustrate the ability of DMFC to respond to the rapidly varying load.

With advancement in fuel cells being used for hybrid vehicular applications, recent studies have shown that DMFC is also a viable option for hybrid system. In this thesis, a dynamic model of DMFC/UC hybrid vehicular power system is also presented. With DMFC and ultracapacitor (UC) operating in parallel, both steady state and peak power demands can be satisfied while providing better efficiency and reducing the FC system cost. Test results obtained using the MATLAB^®, Simulink and SimPowerSystems^® software packages are presented to verify the effectiveness of the proposed scheme.