A strategy for the spatial temperature control of a molten carbonate fuel cell system

The object of the paper is to develop a simple and practical control strategy for a molten carbonate fuel cell (MCFC) system. Based on a dynamic model and the control demand, a cascade control strategy is designed. The master controller imposes a change of cell current representing a change in power demand and sets the amount of fuel gas, the steam-to-carbon ratio, the air number and the cathode gas recycle ratio to their corresponding conditions for optimal steady state electric efficiency. Two feedback PID controllers are in the inner loop, one guarantees the solid temperature not to exceed a maximum temperature by changing the air number around the default set by the master controller; the other controls the maximum temperature difference by adjusting the steam-to-carbon ratio. Step response tests show that this control strategy works well when the cell current changes.