Voltage enhancement of the dc power supplies for dynamic current control of large scale superconducting coils for fusion plasma experimental device LHD

The LHD is a helical-type fusion plasma device using six superconducting coils to form a magnetic field. The fundamental operation of the LHD is performed under a dc magnetic field, and a power system which was suitable for steady state excitation was designed and constructed. With the progress in the fusion plasma research, more dynamic experiments are planned, and require dynamic control of magnetic field. For this purpose, the output voltages of power supplies were enhanced using additional pulse power supplies.