Improving the performance of the JET Shape Controller

Highlights: • Implementation of reliable simulation tool to minimize experimental time for controller tuning. • Improving the inductive decoupling among JET poloidal field coils. • Improving the performance of the specific controlled variables. • New algorithm used in the majority of JET pulses since January 2014. - Abstract: The JET Shape Controller (SC) uses nine distinct circuits, powering the JET poloidal field coils, to control in real time the coil currents, and the plasma shape, current and position. The control scheme presently used [1] is based on a Multiple Input Multiple Output (MIMO) controller, which is designed to decouple the inductive coupling of the different coils. Achieving such a decoupling, the SC allows the user to tune independently the time response of each circuit. As a matter of fact the intended decoupling algorithm has been incorrectly coded in the JET SC system. This paper describes the modelling and experimental activities performed to correct the code error, and to improve the performance on a subset of the controlled parameters.