A combined steady state and dynamic model of a proton exchange membrane fuel cell for use in DG system simulation

This paper proposes a combined steady state (SS) and dynamic model of a proton exchange membrane fuel cell (PEMFC) for use in distributed generation (DG) systems simulation. The SS fuel cell parameters associated with ohmic loss, activation overpotential and concentration over potential which are not easily accessible are estimated using a non-linear fitting of measured V-I fuel cell characteristics. Effect of fuel and air flow dynamics, electrical delay, and delay associated with fuel cell current reference feed back loop on the dynamics of the Nernst potential is modelled. The SS and dynamic models of the FC are then combined to establish a SIMULINK/SIMPOWER terminal model that can easily be interfaced in DG systems simulations. The model SS response is verified using voltage measurements taken by slowly varying the load (current). Simulation results, using SIMULINK/SIMPOWER, are then presented to demonstrate that the model works as desired both for SS and dynamic loads. To demonstrate its applicability in DG Systems simulations, the model is used in long time simulation of an example grid connected FC/Battery Hybrid power system.