Predictive Rotation Profile Control for the DIII-D Tokamak
W. Wehner, E. Schuster, M.D. Boyer, M.L. Walker, D.A. Humphreys
Division of Plasma Physics (DPP) Annual Meeting of the American Physical Society (APS)
Milwaukee, WI, USA, October 23-27, 2017
Abstract
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Control-oriented modeling and model-based control of the rotation
profile are employed to build a suitable control capability for aiding
rotation- related physics studies at DIII-D. To obtain a control-oriented
model, a simplified version of the momentum balance equation is combined
with empirical representa- tions of the momentum sources. The control
approach is rooted in a Model Predictive Control (MPC) framework to
regulate the rotation profile while satisfying constraints associated
with the desired plasma stored energy and/or βN limit. Simple modifications
allow for alternative control objectives, such as maximizing the plasma
rotation while maintaining a specified input torque. Because the MPC
approach can explicitly incorporate various types of constraints, this
approach is well suited to a variety of control objectives, and therefore
serves as a valuable tool for experimental physics studies. Closed-loop
TRANSP simulations are presented to demonstrate the effectiveness of
the control approach.