Stability analysis and model-based control in EXTRAP-T2R with time-delay compensation

Abstract

In this paper, we investigate the stability problems and control issues that occur in a reversed-field pinch (RFP) device, EXTRAP-T2R (T2R), used for research in fusion plasma physics and general plasma (ionized gas) dynamics. The plant exhibits, among other things, magnetohydrodynamic instabilities known as resistive-wall modes (RWMs), growing on a time-scale set by a surrounding non-perfectly conducting shell. We propose a novel model that takes into account experimental constraints, such as the actuators dynamics and control latencies, which lead to a multivariable time-delay model of the system. The openloop field-error characteristics are estimated and a stability analysis of the resulting closed-loop delay differential equation (DDE) emphasizes the importance of the delay effects. We then design a structurally constrained optimal PID controller by direct eigenvalue optimization (DEO) of this DDE. The presented results are substantially based on and compared with experimental data.

DOI: 10.1109/CDC.2008.4738882

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Cite this paper

@inproceedings{Olofsson2008StabilityAA, title={Stability analysis and model-based control in EXTRAP-T2R with time-delay compensation}, author={Erik Olofsson and Emmanuel Witrant and Corentin Briat and Silviu-Iulian Niculescu and Per Brunsell}, booktitle={CDC}, year={2008} }