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Title: Adaptive optimal stochastic state feedback control of resistive wall modes in tokamaks

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.2161168· OSTI ID:20782454
; ;  [1]
  1. Electrical Engineering Department, Columbia University, New York, New York 10027 (United States)

An adaptive optimal stochastic state feedback control is developed to stabilize the resistive wall mode (RWM) instability in tokamaks. The extended least-square method with exponential forgetting factor and covariance resetting is used to identify (experimentally determine) the time-varying stochastic system model. A Kalman filter is used to estimate the system states. The estimated system states are passed on to an optimal state feedback controller to construct control inputs. The Kalman filter and the optimal state feedback controller are periodically redesigned online based on the identified system model. This adaptive controller can stabilize the time-dependent RWM in a slowly evolving tokamak discharge. This is accomplished within a time delay of roughly four times the inverse of the growth rate for the time-invariant model used.

OSTI ID:
20782454
Journal Information:
Physics of Plasmas, Vol. 13, Issue 1; Other Information: DOI: 10.1063/1.2161168; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
Country of Publication:
United States
Language:
English