Design and Simulation of ISTTOK Real-Time Magnetic Multiple-Input Multiple-Output Control

Abstract

Control of the plasma current and the position of its centroid and its shape is vital for obtaining advanced performance regimes in tokamak operation. For that aim, the use of poloidal magnetic coils for feedback control is essential. In this paper, a multiple-input multiple-output (MIMO) optimal control algorithm for the vertical and horizontal control position of the plasma current centroid at IST tokamak (ISTTOK) is presented. Using the ISTTOK magnetic system, the real-time control is made possible by the execution of generic application modules (GAMs), developed to be executed on the Multithreaded Application Real-Time executor ISTTOK controller. The design of the proposed MIMO controller is based on a state-space model of the ISTTOK magnetic response that has been identified from experimental data. Both the control design and the identification procedure rely on the reconstruction of the plasma centroid position computed by the magnetic probes (Mirnov coils) installed at ISTTOK. The centroid position is reconstructed in the Position GAM by numerical integration of the magnetic probes signals in the recently upgraded hardware based on the Advanced Telecommunications Computing Architecture. The effectiveness of the proposed control approach is presented comparing simulation results with experimental ones obtained using single-input single-output PID controllers. Moreover, due to the modularity of the ISTTOK control system, the proposed real-time reconstruction algorithm has been easily deployed on the plant, and the same approach will be adopted to test the MIMO controller in the future.