Fault tolerant control of an anode offgas recycle based SOFC system

This research investigates the solid oxide fuel cell system (SOFC) control problems by applying the anode offgas recycle (AOR),when the system is with normal operating state and affected by the stack degradation disturbance, respectively. The AOR structure is first introduced for the tolerant control of hydrogen-fuel SOFC systems. The stack degradation disturbance is simulated by the First Order Plus Dead Time (FOPDT) transfer function. Based on the AOR a Fault Tolerant Control (FTC) strategy is designed to control the system under the stack degradation circumstance. It is shown by simulation results that the FTC can maintain the system temperatures within a safety margin and guarantee the fuel utilization at a high level when the stack degradation occur, but the conventional control lose efficacy.