Feed-forward control of a solid oxide fuel cell system with anode offgas recycle

In this work a combined heat and power unit (CHP unit) based on the solid oxide fuel cell (SOFC) technology is analysed. This unit has a special feature: the anode offgas is partially recycled to the anode inlet. Thus it is possible to increase the electrical efficiency and the system can be operated without external water feeding. A feed-forward control concept which allows secure operating conditions of the CHP unit as well as a maximization of its electrical efficiency is introduced and validated experimentally. The control algorithm requires a limited number of measurement values and few deterministic relations for its description. •A feed-forward control for SOFC system with anode offgas recycle was developed.•The control strategy requires a limited number of variables and relations.•A prototype of SOFC system with anode offgas recycle has been started-up.•The start-up procedure does not require any liquid water feeding.•The prototype shows a gross electrical efficiency larger than 60%.