Dynamic modeling and simulation of a DMFC/UC based hybrid vehicular system

Fuel cell (FC) technology has proven to be a viable solution for vehicular applications. The most widely used FC for vehicular application is Proton Exchange Membrane Fuel Cell (PEMFC). However, limitations of PEMFC such as need of reformer and hydrogen storage concerns have demanded a search for better options. Direct Methanol Fuel Cell (DMFC) has shown remarkable promise to overcome these limitations because it does not require a reformer and has no storage issues reported till date. A standalone FC system may not be sufficient to satisfy the overall load demands of a vehicle, especially during cold start, peak power demand and transient events. Furthermore, FC is a unidirectional power unit and it cannot operate in the reverse direction. An ultra-capacitor (UC) bank has high power density and can supply large bursts of power for short durations. By integrating the FC and UC in parallel, both steady state and peak power demands can be satisfied resulting in better efficiency and reduced system cost. This paper proposes a dynamic model of DMFC/UC hybrid vehicular power system. Test results obtained using the MATLAB^®, Simulink and SimPowerSystems^® software packages are presented to verify the effectiveness of the proposed scheme.