Performance optimisation of tokamak operation in ASDEX Upgrade through novel feedback control capabilities

Abstract Optimising the performance of tokamak operation is not only a matter of tuning individual control loops, but needs a holistic approach with a focus on the effective interplay of all control system components. The ASDEX Upgrade Discharge Control System (DCS) has enabled outstanding results of physics effect studies and operation scenario development. This is facilitated by efficient and highly robust algorithms for measurements data processing and plasma state estimation, a versatile feedback control suite, a powerful actuator management approach that optimises the utilisation of the limited number of actuators, and pulse supervision control reacting to events and plasma state conditions to achieve a maximum exploitation of the pulse and protect device and investment. Moreover, Fenix, a fast “flight simulator” with a full model of the control system and a control-oriented plasma and plant model, assists in scenario design, validation and control method development, thus accelerating the turnaround time from the design of emerging capabilities to their exploitation in plasma pulses. Larger and more complex fusion devices such as ITER and DEMO in particular, will benefit from such a control structure and active contributions are being made to the architectural design of their control systems.