Electrical modeling of HF coupled inductors supplying a double frequency inductive plasma reactor

A new inductive plasma reactor has been developed for metal coating. It combines magnetic plasma generation at 13.56 MHz and induction heating at 100 kHz. The unavoidable coupling of the two coaxial coils allows one electrical generator to force power in the other, compromising the reliability of the system, except if rejecting filters are inserted. Therefore, an equivalent circuit of the double coil set is needed to specify and design the necessary filters. The aim of this paper is to present and justify the electrical representation of this very special high frequency transformer which have been used successfully.