Feedback control of plasma position in the HL-1 tokamak

A feedback control system is installed in the HL-1 tokamak with a thick copper shell (d=5 cm). The control field coils outside the copper shell are fed by a six-pulse thyristor rectifier. The power supply is operated by a pulse-width-modulated regulator which consists of a dual-mode circuit without dead zone and a PID circuit. The operation on the HL-1 shows that the horizontal and vertical plasma positions can be controlled to +or-2 mm.< >