Multivariable Model-based Shape Control for the National Spherical Torus Experiment (NSTX)
Division of Plasma Physics (DPP) Annual Meeting of the American Physical Society (APS)
Chicago, Illinois, November 8-12, 2010
Abstract |
Because of the coupling between the different geometrical parameters, multi-input-multi-output (MIMO) model-based shape controllers are necessary to achieve the very stringent plasma shape requirements in highly-efficient tokamaks. Leveraging the availability of rtEFIT, we propose a robust model-based MIMO controller to provide real-time shaping and position control of the plasma in NSTX. The proposed controller is composed of three loops that transform the shape control problem into a tracking problem. A singular value decomposition of the plasma model is carried out to define the weights associated to the tracking errors. The H∞ technique is used to minimize the tracking errors and optimize input efforts. Computer simula- tion results illustrate the performance of the robust shape controller, showing the potential for improving the performance of present non-model-based controllers.