Comparison of strategies and regulator design for active control of MHD modes

Cavinato, M.; Gregoratto, D.; Marchiori, G.; Paccagnella, R.; Brunsell, Per R.; Yadikin, Dmitriy

doi:10.1016/j.fusengdes.2005.06.248

Cited by 3 publications

(3 citation statements)

References 11 publications

(12 reference statements)

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“…The digital controller is a prototype of the controller developed for the RFX device at Padova [4]. In the feedback mode, the controller performs a real time FFT on the sensor coil data and utilizes a feedback law to determine the control harmonics.…”

Section: Feedback Control Experimentsmentioning

confidence: 99%

Experimental and theoretical studies of active control of resistive wall mode growth in the EXTRAP T2R reversed-field pinch

Drake¹,

Brunsell²,

Yadikin³

et al. 2005

Nucl. Fusion

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Active feedback control of resistive wall modes (RWMs) has been demonstrated on the EXTRAP T2R reversed-field pinch experiment. The control system includes a sensor consisting of an array of magnetic coils (measuring mode harmonics) and an actuator consisting of a saddle coil array (producing control harmonics). Closed-loop (feedback) experiments using a digital controller based on a real time Fourier transform of sensor data have been studied for cases where the feedback gain was constant and real for all harmonics (intelligent-shell) and cases where the feedback gain could be set for selected harmonics, with both real or complex values (targeted-harmonics). The growth of the dominant RWMs can be suppressed by feedback for both the intelligent-shell and targeted-harmonic control systems. Because the number of toroidal positions of saddle coils in the array is half the number of sensors, it is predicted and observed experimentally that the control harmonic spectrum has sidebands. As a result, each control harmonic has to control simultaneously two mode harmonics. Real gains can stabilize non-rotating RWMs, while complex gains give better results for (slowly) rotating RWMs. In addition open loop experiments have been used to observe the effects of resonant field errors applied to unstable, marginally stable and robustly stable modes. The observed effects of field errors are consistent with the thin-wall model, where mode growth is proportional to the resonant field error amplitude and the wall penetration time for that mode harmonic.

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Section: Feedback Control Experimentsmentioning

confidence: 99%

Experimental and theoretical studies of active control of resistive wall mode growth in the EXTRAP T2R reversed-field pinch

Drake¹,

Brunsell²,

Yadikin³

et al. 2005

Nucl. Fusion

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“…III. FEEDBACK CONTROL Several different schemes are considered for the active control of field errors and MHD modes [3].…”

Section: Open Loop Electromagnetic Characterizationmentioning

confidence: 99%

“…The choice of a proportional complex gain regulator comes from the experience acquired on the T2R machine [3,4] with a similar saddle coil system. Starting from a simple proportional controller helps in getting a good insight on the closed loop dynamics.…”

Section: A Virtual Shellmentioning

confidence: 99%

Characterization of the RFX-mod Saddle Coil System and design of the regulator for the control of MHD modes

Cavinato

Chitarin

Grando

et al. 2005

21st IEEE/NPS Symposium on Fusion Engineering SOFE 05

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The RFX-mod layout is equipped with a complex system for the active control of MHD modes. The system has been fully commissioned and a plasmaless experimental campaign was devoted to its characterization. Several tests were performed in presence of plasma in order to commission the implementation of the main algorithms developed to drive the saddle coils. The results of the tests are very encouraging in terms of plasma performances and are presented in the paper along with discussion of the characterization results and a description of the control schemes adopted.

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MHD modes control in fusion devices

Cavinato

Marchiori

Soppelsa

et al. 2006

Proceedings of the 45th IEEE Conference on Decision and Control

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The control of the 3D deformations of the plasma column due to MHD modes is becoming a crucial issue in modern fusion experiments since it is a prerequisite for operation at high beta and is essential for the advanced configurations. Aim of the paper is to present some issues related to the design of the mode control system which are of general interest for experimental reactors. The work presented mainly originates from the studies performed on the RFX-mod machine which is equipped with the most flexible and complete saddle coils system available, at present, for experimenting the control of MHD plasma modes. The paper focuses in particular on the multivariable linear model developed for the design of the controller and on the different strategies envisaged for the stabilization of the modes. Some results obtained in RFX-mod with the designed algorithms are also proposed along with some issues specific to configurations with a limited number of saddle coils available as actuator

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Comparison of strategies and regulator design for active control of MHD modes

Cited by 3 publications

References 11 publications

Experimental and theoretical studies of active control of resistive wall mode growth in the EXTRAP T2R reversed-field pinch

Experimental and theoretical studies of active control of resistive wall mode growth in the EXTRAP T2R reversed-field pinch

Characterization of the RFX-mod Saddle Coil System and design of the regulator for the control of MHD modes

MHD modes control in fusion devices

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