Model-based Linear Quadratic Integral Control Design for q-profile Shaping in EAST

In order to achieve advanced modes of operation, characterized by confinement improvement and possible steady-state operation, control capabilities for shaping the spatial profile of the toroidal current density, or equivalently the safety factor $q$ or the gradient of the poloidal magnetic flux, are essential. A linear quadratic integral (LQI) control-design approach has been followed in this work to further develop such control capabilities in EAST. The controllers, which have been designed based on a first-principles-driven control-oriented model of the poloidal magnetic flux profile evolution, have the capability of regulating several points of the q profile and its integral properties such as the internal inductance $l_{i}$. Moreover, by controlling the plasma current \textit{Ip} and the powers of both the low frequency (2.45 GHz) and the high-frequency (4.60 GHz) lower hybrid wave sources, the controllers can also regulate $\beta _{N}$. Nonlinear simulations show that the controllers can effectively regulate a combination of $q$(0.1), $q$(0.5), $q$(0.9), $l_{i}$ and $\beta_{N}$. The proposed control laws have been implemented in the recently developed Profile Control category in the EAST Plasma Control System (PCS) with the ultimate goal of testing them experimentally.