Modeling of SOFC System Reduction and Simulation Testing

As a high order and non-linear complex system, a control-oriented reduced order model is first designed for the 5kW solid oxide fuel cell (SOFC) system, and then its dynamic and static performances with the four temperature layers, three temperature layers, and two temperature layers are respectively discussed. Although the simulation results show some theoretical design error with the different operating points in the different temperature layer system model, including the electrical static output characteristics (V-P characteristic curve, current density distribution), thermal static output characteristic (solid layer temperature, temperature distribution at the air side), and fluid static output characteristics (H
2
O > H
2
and O
2
), the reduced order system model can reflect the static characteristics of the SOFC stand-alone system pretty accurately. As the response curve and response time scale of dynamic output characteristics (current density, fuel cell output voltage, and system output power) tend the same in the different temperature layers model, thus it can be argued that the characteristics of the original model are very effectively retained in the reduced order model. Finally, two temperature layers model not only dramatically reduces the complexity of the model, but also shows the higher precision, which should be preferred in the controller design.