Multi-experiment state-space identification of coupled magnetic and kinetic parameters in tokamak plasmas

Mavkov, Bojan; Witrant, Emmanuel; Prieur, Christophe; Moreau, D.

doi:10.1016/j.conengprac.2016.12.006

Cited by 7 publications

(7 citation statements)

References 37 publications

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“…Using the first version of the system, with generic controllers and a preliminary actuator manager, RT integrated control of NTMs, β and model-estimated q profiles has been demonstrated on TCV. The details of various β and q profile controllers have been presented in references [23][24][25], and here we only concentrate on the generic NTM controller. As shown in figure 21 and preliminarily presented in reference [26], three EC launchers (L1, L4 and L6) are used to perform the three control tasks.…”

Section: Rt Integrated Control Of Ntms β and Model-estimated Q Profimentioning

confidence: 99%

“…For large devices like ITER, supervising the plasma discharge evolution and performing multiple control tasks sharing a limited set of actuators are essential [12]. This requires reliable RT plasma state reconstruction, monitoring and supervision [21], actuator management [22] and controllers [22][23][24][25][26]. With the NTM controller mentioned above and following a generic integrated control framework [21,22], integrated control of NTMs, β (the ratio of plasma pressure to magnetic pressure) and model-estimated safety factor (q) profiles has been demonstrated on TCV.…”

Section: Introductionmentioning

confidence: 99%

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Control of neoclassical tearing modes and integrated multi-actuator plasma control on TCV

et al. 2019

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The control of 2/1 neoclassical tearing modes (NTMs) with electron cyclotron (EC) waves has been studied both experimentally and numerically on TCV. Dynamic evolutions of NTMs along with time-varying deposition locations of the control beam have been studied in detail. The prevention of NTMs by means of preemptive EC (i.e. the control beam is switched on before the mode onset) has also been explored. A small sinusoidal sweeping with full amplitude of 0.07 (normalized to the minor radius) has been added to the control beam in two of the experiments to facilitate the comparison between NTM stabilization and prevention. It is shown that the prevention of NTMs is more efficient than NTM stabilization in terms of the minimum EC power required. Interpretative simulations with the Modified Rutherford Equation (MRE) have been performed to better quantify various effects, with coefficients well defined by dedicated experiments. Specifically, in order to obtain more insight on the dominant dependencies, a simple ad-hoc analytical model has been proposed to evaluate the time-varying classical stability index ∆ in the test discharges, based on the ∆ -triggered nature of these 2/1 NTMs. This allows simulating well the entire island width evolution with the MRE, starting from zero width and including both NTM stabilization and prevention cases for the first time. The exploration of NTM physics and control has facilitated the development of an NTM controller that is independent of the particular features of TCV and has been included in a generic plasma control system (PCS) framework. Integrated control of 2/1 NTMs, plasma β (the ratio of plasma pressure to magnetic pressure) and model-estimated safety factor q profiles has been demonstrated on TCV.

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Section: Rt Integrated Control Of Ntms β and Model-estimated Q Profimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Control of neoclassical tearing modes and integrated multi-actuator plasma control on TCV

et al. 2019

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“…See [21,22,23,24] for Lyapunov design control on the safety factor dynamics. See [139,141] with the coupling with electron temperature profile and finally [140] for real experiments on the tokamaks using Lyapunov based control and ISS properties.…”

Section: Applicationsmentioning

confidence: 99%

Input-to-state stability of infinite-dimensional systems: recent results and open questions

Mironchenko¹,

Prieur²

2019

Preprint

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In a pedagogical but exhaustive manner, this survey reviews the main results on input-to-state stability (ISS) for infinite-dimensional systems. This property allows to estimate the impact of inputs and initial conditions on both the intermediate values and the asymptotic bound on the solutions. ISS has unified the input-output and Lyapunov stability theories and is a crucial property in stability theory of control systems as well as for many applications whose dynamics depend on parameters, unknown perturbations, or other inputs. In this paper, starting from classic results for nonlinear ordinary differential equations, we motivate the study of ISS property for distributed parameter systems. Then fundamental properties are given, as an ISS superposition theorem and characterizations of (global and local) ISS in terms of Lyapunov functions. We explain in detail the functional-analytic approach to ISS theory of linear systems with unbounded input operators, with a special attention devoted to ISS theory of boundary control systems. Lyapunov method is shown to be very useful for both linear and nonlinear models, including parabolic and hyperbolic partial differential equations. Next, we show the efficiency of ISS framework to study stability of large-scale networks, coupled either via the boundary or via the interior of the spatial domain. ISS methodology allows reducing the stability analysis of complex networks, by considering the stability properties of its components and the interconnection structure between the subsystems. An extra section is devoted to ISS theory of time-delay systems with the emphasis on techniques, which are particularly suited for this class of systems. Finally, numerous applications are considered in this survey, where ISS properties play a crucial role in their study. This survey contains recent as well as classical results on systems theory and suggests many open problems throughout the paper.

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“…selection of operating condition or selection of informative data). Examples of such applications include: the linearmodeling of helicopter ight-mechanics from multiple short ight data [1]; the identication of linear-models for Lithium-Ion batteries and tokamaks with data from multiple experiments [2,3]; and the modeling of Linear Parameter-Varying systems from a local approach where, after operating condition selection, multiple records are available to identify a local Linear Time-Invariant (LTI) model [4].…”

Section: Introductionmentioning

confidence: 99%

On the consistency and asymptotic normality of discrete-time LTI models identified from concatenated data sets

2022

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Multi-experiment state-space identification of coupled magnetic and kinetic parameters in tokamak plasmas

Cited by 7 publications

References 37 publications

Control of neoclassical tearing modes and integrated multi-actuator plasma control on TCV

Control of neoclassical tearing modes and integrated multi-actuator plasma control on TCV

Input-to-state stability of infinite-dimensional systems: recent results and open questions

On the consistency and asymptotic normality of discrete-time LTI models identified from concatenated data sets

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