This paper provides two types of control relevant models of planer solid oxide fuel cell system with different details. Dynamic models of system components which include heat exchanger, reformer and after-burner are also provided along with the necessary formulation of a fuel cell connected in parallel with a capacitor. Steady-state and dynamic simulations of fuel cell system for both types of models are performed. The results indicate that both models are comparable in predicting stack voltage at lower current load. But, the discrepancy in the stack voltage, power and temperature of different components become more prominent at higher current load. (c) 2006 Elsevier B.V. All rights reserved.