Control upgrade for the TCV coils power supplies

The Tokamak a` Configuration Variable (TCV) coil converters are fed, during the plasma pulse, by a flywheel generator (FG) providing the AC voltages few seconds before the plasma pulse. The synchronization with the 120 Hz frequency delivered by the FG, varying rapidly during the plasma pulse (up to 25 Hz/sec) is therefore one of the two main challenges of this work. The second one being the extraction of the synchronization signal in presence of the notches on the AC voltages due to thyristors commutations, in order to ensure a proper and accurate firing sequence. This has been solved making use of an innovative implementation of a PLL. Another important feature of this ongoing upgrade is the ability of the controller to be driven by digital voltage references directly transmitted via EtherCAT [1] through the future digital calculator which will ensure the plasma equi-libria. Open Platform Communications Unified Architecture (OPC UA) [2] will be used as an upgraded protocol allowing for the TCV Control to interact with the converters interface (HMI).