Real Time Control of a Fast RF Impedance Matching System

A real time control system has been developed to maintain an RF impedance match in the ion cyclotron range of frequencies (ICRF). This system is designed to adjust output parameters with a cycle period of approximately 100 useconds using commercially available VME based components and a UNIX workstation host. Advanced Ferrite Technologies (AFT) has developed the hybrid tuning system (HTS) which has the capability of tracking a mismatch on the time scale of milliseconds (2.5 MW, 60 MHz) by varying the magnetic field bias of ferrite loaded transmission lines. The control algorithm uses a combination of neural network and fuzzy logic techniques. Initial results of a test facility using a low power prototype are presented.