ITER-like vertical stabilization system for the east Tokamak

A ITER-like vertical stabilization (VS) algorithm has been successfully deployed and commissioned at EAST. The proposed algorithm decouples the VS from the plasma shape control, while the algorithms previously implemented to stabilize the EAST plasma exhibit a strong coupling with plasma shape control system. As a consequence, the VS algorithms previously implemented at EAST prevent the deployment of advanced multi-input-multi-output (MIMO) plasma shape control schemes, such as the ones proposed in Albanese et al 2016 (Proc. 2016 IEEE Multi-Conf. System Control (Buenos Aires, Argentina) pp 611–6) and Kolemen et al (2015 J. Nucl. Mater. 463 1186). Indeed, such MIMO controllers rely on the decoupling with the VS system. The proposed ITER-like stabilizes the plasma column (i.e. it controls to zero the plasma vertical speed) on the fastest possible time scale, while leaves the control of the plasma vertical position to the plasma shape controller. Thanks to this frequency separation approach, the plasma shape controller can than be designed starting from the stabilized system, without explicitly taking the VS into account. In this paper we present the implementation details of the adopted solution for the EAST vertical stabilization, together with the results obtained during the 2016 experimental campaign.