Identification and Control of Magneto-Kinetic Response During Advanced Tokamak Scenarios in DIII-D
W. Wehner, W. Shi, E. Schuster, D. Moreau, M.L. Walker, J.R. Ferron, T.C. Luce, D.A. Humphreys, B.G. Penaflor and R.D. Johnson
American Control Conference
Washington, DC, USA, June 17-19, 2013
Abstract
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The paper proposes a model-based control approach for the coupled
evolution of the poloidal magnetic flux profile and the normalized
pressure ratio beta_N. The model is determined by a system
identification method which is shown to sufficiently reproduce the
plasma response to variations in particular actuators. Data for model
identification is collected during the plasma current flattop in a
large beta_N, high-confinement scenario (H-mode) with the actuators
modulated in open loop. Using this data, a linear state-space plasma
response model for the poloidal magnetic flux profile and beta_N
dynamics around a plasma equilibrium state is identified. An optimal
state feedback controller with integral action is designed for the
purpose of simultaneous control of the poloidal flux profile and
beta_N. Experimental results showing the performance of the proposed
controller implemented in the DIII-D tokamak are presented.