Implementation on a mock-up of the automatic feedback controlled matching options of the full ITER ICRH system

The hybrid option has been chosen for the matching of the ITER ICRH system. Presently, the corresponding 3 dB hybrid matching circuit is being developed, and tested for optimization on a low-powered scaled mock-up. Impedance matching and antenna array current control of the hybrid option is provided by simultaneous feedback control of the decouplers and double stub tuners (23 actuators in total) and is being progressively implemented. Already half of the array has been successfully tested. The article goes into the details of the automatic feedback implementation and covers the developed control systems and algorithms. Feedback stability and starting conditions are also discussed.