Study on control strategy for a SOFC-GT hybrid system with anode and cathode recirculation loops

The solid oxide fuel cell-gas turbine (SOFC-GT) hybrid power generation system offers a possible technology of high efficiency combined with low emissions. Due to its highly coupled system and complex dynamic characteristics, several vital parameters such as fuel cell temperature, thermal stress, steam-to-carbon, turbine inlet temperature, and compressor surge margin must be controlled and restricted to a feasible zone to guarantee the safe operation of the hybrid system. A novel control strategy was carried out for the SOFC-GT hybrid system with anode and cathode recirculation loops. In the SOFC thermal management system, two control loops were introduced to keep anode temperature and cathode temperature. The behaviors of the control system were compared with the control system without an anode temperature control loop during load following. The results reveal that the anode channel temperature and cathode channel temperature should both be controlled to avoid huge temperature differences and temperature gradient in SOFC. The designed control system 1 in this study for the hybrid system is feasible and effective.