Implementation and Initial Testing of a Model Predictive Controller for Safety Factor Profile and Energy Regulation in the EAST Tokamak

Z. Wang, H. Wang, E. Schuster, Z. Luo, Y. Huang, Q. Yuan, B. Xiao, D. Humphreys, S.T. Paruchuri

American Control Conference (ACC)

San Diego, CA, USA, May 31 – June 2, 2023

Abstract

The tokamak, a potential candidate for realizing nuclear fusion energy on Earth, uses strong magnetic fields to confine a hot ionized gas (plasma) in a toroidal vacuum chamber. The ability of tokamaks to run in high-performance modes of operation demands advanced control capabilities to regulate the spatial distribution (profile) of several plasma properties such as the safety factor q. A model predictive control (MPC) approach has been followed to further advance such control capabilities for the EAST tokamak. The proposed controllers have the capability of simultaneously regulating the q-profile and the plasma stored energy W by controlling the plasma current Ip, the individual powers of four neutral beam injectors (NBI1L, NBI1R, NBI2L, NBI2R), and the powers of two lower hybrid wave sources with different frequencies (2.45 GHz, 4.60 GHz). An active-set algorithm has been employed to solve the Quadratic Programming (QP) problem arising from the MPC formulation. Initial experimental tests of the MPC show that the real-time optimization is successfully carried out within the time constraints imposed by the dynamics of the plasma.