Abstract
In this paper, the control system which has been proposed to upgrade the toroidal field coil (TFC) power source at JFT-2M tokamak machine in Japan Atomic Energy Reseach Institute is presented. This power source, us-ing four dc generator-motors with flywheel (DCG) for storing 210MJ of the energy, can produce 51.3MW (2.7kV, 19kA) of the flat top over 1 sec. The control characteristics of the DCG operating as generator are described, especially emphasized such features as the unique method for opening the contactor of a main-circuit-switch by controlling the field current of DCG. A pair of thyristor convertors for DCG exiciter are used not only for rapidly varing the coil current between zero and 19kA, which are original purposes, but also for reducing it to less 10A to make the contactor of the gaseos circuit braker (GCB) for the switch open. The system configuration and the operating principle of the proposed control system are explained, and the basic characteristics which have been investigated by solving directly the linearized equations for the system or the analog simulation for it are presented. The required performance has been achieved through the field-tests, and some of test results were compared and got good agreement with the simulation results.
