GRDG analysis of the ALSTOM gasifier benchmark process under model plant mismatch

An optimization based method for determining relative disturbance gain array (RDGA) range for uncertain system is presented and is then applied to control structure analysis of the ALSTOM gasifier benchmark process. Reduced order linear models were identified from simulated plant operating data. Several different models were obtained under different operating conditions and model uncertainty bounds were obtained from those models. The generalized relative disturbance gain (GRDG) ranges under plant model uncertainty were then determined from a structure selection matrix in conjunction with relative disturbance gain array (RDGA) range and used in selecting robust decentralized control structure. GRDG bounds are particularly useful for control structure determination and the related robustness as they provide information regarding the sensitivity to gain uncertainties.