Robust Control of the Spatial Current Profile in the DIII-D Tokamak
J. Barton, E. Schuster, M. L. Walker and D. A. Humphreys
Division of Plasma Physics (DPP) Annual Meeting of the American Physical Society (APS)
Salt Lake City, Utah, USA, November 14-18, 2011
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Abstract
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Advanced tokamak operating scenarios, characterized by large
noninductively driven plasma currents, typically require active
regulation of a specific current density profile. Non-model-based
control of the q profile has been tested at DIII-D. However, some
present limitations of the controller motivate the design of a
model-based controller that accounts for the dynamics of the whole q
profile in response to the control actuators. A control-oriented model
of the current profile evolution in DIII-D was recently developed and
used to design feedforward control schemes. In order to reject the
effects of external disturbances to the system, a feedback control
input needs to be added to the feedforward input. In this work, we
report on the design of a robust feedback controller, on the
implementation of the combined model-based feedforward + feedback
controller in the DIII-D Plasma Control System, and on the experimental
validation of the combined controller in the DIII-D tokamak.
