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 the one produced with standard H_∞ design techniques