Application of cautious stable predictive control to vertical positioning in COMPASS-D tokamak

Recent advances in guaranteed stable generalized predictive control algorithms are applied to vertical positioning of plasma in the COMPASS-D tokamak, a test device used to study instabilities and control techniques necessary for fusion power plants in the future. The tokamak current P+D controller cannot stabilize the plasma vertical position without internal sensors which will not be available in larger devices. A controller which is derived,with the stable predictive control algorithms described in this paper stabilizes the plasma with only external sensors and also solves noise and robustness problems; it compares favorably to one produced with standard H-infinity design techniques.