Plasma position control in SST1 tokamak

Abstract

For long duration steady state operation of SST1, it would be very crucial to maintain the plasma radial and vertical positions accurately. For designing the position controller in SST1 we have adopted the simple linear RZIP control model. While the vertical position instability is slowed down by a set of passive stabilizers placed closed to the plasma edge, a pair of in-vessel active feedback coils can adequately control vertical position perturbations of up to 1 cm. The shifts in radial position arising due to minor disruptions would be controlled by a separate pair of poloidal field (PF) coils also placed inside the vessel, however the controller would ignore fast but insignificant changes in radius arising due to edge localised modes. The parameters of both vertical and radial position control coils and their power supplies are determined based on the RZIP simulations.

Modeling and robust decentralized control system design for plasma current and position in Damavand tokamak

“…The plasma dynamic model in DT as shown in equation (3) has four inputs and three outputs so the transfer function of the system in an operating point is as equation (7). The frequency response of the nonsquare-DRGA of the system in the presence of uncertainty, equation (7), has been shown in figure 9. The following results can be concluded from figure 9:…”

“…RZIP is a three degrees-of-freedom model of the current, radial, and vertical position, which has been developed based on the Hamiltonian mechanics and was implemented in TCV [6]. A simple linear RZIP model was adopted to design the position controller in SST1 [7]. The generalized RZIP model was validated based on the open-loop response in JT-60U [8].…”

Using LQR controller for vertical position control on EAST

“…In the DIII-D, an anti-windup compensator was implemented for a particular nominal plasma vertical controller, which ensured global vertical stabilization of the plasma in actuator saturation for all reference commands [8]. In the SST1, the RZIP model is applied to the vertical position control, and the control system is evaluated for the effects of various disturbances [9]. In the TCV, a structured H-infinity design extending classical H-infinity to fixed-structure control systems was applied to obtain an optimized controller using all available coils for position control [10].…”

Design and Implementation of nonlinear neural network controller based on simulator model in Damavand Tokamak

“…Actuator circuits of GLOBUS-M Tokamak were simulated and plasma vertical motion was simulated by DINA code and consequently PID controller was designed to control plasma vertical motion in 2004 [8]. Simple linear RZIP control model was considered to control of plasma position in SST1 Tokamak in 2000 [9].…”