Anti-windup Scheme for Plasma Shape Control with Rate and Magnitude Actuation Constraints in the DIII-D Tokamak
E. Schuster, M.L. Walker, D.A. Humphreys and M. Krstic
42nd IEEE Conference on Decision and Control
Maui, Hawaii, USA, December 2003
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Abstract
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The Advanced Tokamak (AT) operating mode is the principal focus of the
DIII-D tokamak. In order to be prepared for the higher control demands
arising in AT scenarios, current efforts are focused on the
development of an integrated multivariable controller to take into
account the highly coupled influences of equilibrium shape, profile,
and stability control. The first step of this project is the design of
the shape and vertical controller which will be integrated in the
future with control of plasma profiles. The time-scale properties of
the system allow the separation of the vertical stabilization problem,
approached by the authors in prior work, from the shape control
problem, which is the focus of this paper. Ensured the vertical
stability of the plasma, in this work we implement an anti-windup
compensator that keeps the given nominal shape controller well-behaved
in the presence of rate and magnitude constraints at the input of the
nonlinear plant. The anti-windup synthesis problem is to find a
nonlinear modification of the nominal linear controller that prevents
undesirable oscillations but leaves the nominal closed loop unmodified
when there is no input saturation.
