Control system of dc power supplies for LHD superconducting coils

The LHD is a fusion plasma experimental device and it has six dc power supplies to excite three sets of superconducting helical coils and three sets of superconducting poloidal coils. Although the basic operation of an LHD experiment is performed under the dc magnetic field, some experiments require dynamic control of the magnetic field. For the dynamic excitation of coils, all of the output current of power supplies must be controlled by the current regulator which takes into account the coupling between coils. This paper introduces the control system of the dc power supplies for the LHD. The outline of the system, the state control scheme, the current regulator, and some dynamic operation results are described.