A time-delay approach for the modeling and control of plasma instabilities in thermonuclear fusion

Abstract : This letter presents a summary of [1], where we investigated the stability problems and control issues that occur in a reversedfield pinch (RFP) device, EXTRAP-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 new modeling approach that takes into account experimental constraints, such as the actuators dynamics and control latencies leading to a multivariable time-delay model of the system. The open-loop 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 an optimal PID controller (its structure being constrained by the intelligent-shell (IS) control architecture) that achieves a direct eigenvalue optimization of the corresponding DDE. The presented results are substantially based on and compared with experimental data.
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https://hal.archives-ouvertes.fr/hal-00444540
Contributor : Emmanuel Witrant <>
Submitted on : Wednesday, January 6, 2010 - 5:35:20 PM
Last modification on : Thursday, August 22, 2019 - 11:32:03 AM
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  • HAL Id : hal-00444540, version 1

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Emmanuel Witrant, Erik Olofsson, Silviu-Iulian Niculescu. A time-delay approach for the modeling and control of plasma instabilities in thermonuclear fusion. 2009. ⟨hal-00444540⟩

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