High-power pulse transformer for a 1.5-MW magnetron of KSTAR LHCD microwave application

Abstract

The microwave heating system of KSTAR consists of ECH and LHCD. ECH and LHCD offer reliability of operation at the beginning of plasma formation and non-inductive current drive for long-time steady-state operation, respectively. LHCD demands a C-band microwave system with a frequency of 5 GHz. A pulse generator with a power of 3.6 MW, 4 mu s, 200 pps is required to drive a high-power magnetron. The high power pulse transformer has the function of transferring pulse energy from a pulsed power source to a high-power load. A pulse transformer producing a pulse with a peak voltage of 45 kV is required to produce a 5 GHz microwave source in a 1.5 MW magnetron. We have designed the high-power pulse transformer with 1 : 4 step-up ratio. The peak power handling capability is 3.6 MW (45 W, 90 A at load side with 4 mu s pulse width). In this paper, a system overview and test results of the high power pulse transformer are presented.