Model predictive control of ITER plasma current and shape using singular-value decomposition

A model predictive control (MPC) scheme for ITER plasma current and shape controller (PCSC) is presented. The controller is able to control a large number of geometrical plasma shape descriptors using output-space reduction based on singular-value decomposition (SVD). The online optimisation problems imposed by MPC are solved using the dual fast gradient method (dFGM) solver, which is shown to be computationally feasible when MPC complexity-reduction techniques are applied. A performance evaluation in simulation of the flat-top phase of ITER Scenario 1 is presented, showing a moderate general improvement of control, compared to a reference control scheme based on multivariable PID control with SVD. Moreover, the proposed MPC PCSC is capable of avoiding superconductive current saturations, and in some cases shows better performance regarding voltage saturations.