A feedback control system is needed to restrain plasma vertical displacement in EAST(Experimental Advanced Superconducting Tokamak).A fast control power supply excites active feedback coils,which produces a magnetic field to control the plasma's displacement.With the development of EAST,new demands on the new fast control power supply have led to an enhanced ability of fast response and output current,as well as a new control mode.The structure of cascaded and paralleled H-bridges can meet the demand of extended capacity,and digital control can realize current and voltage mixed control mode.The validity of the proposed scheme is confirmed by experiments.
The effectiveness of the magnetic confinement of plasma can be improved by elongating the plasma cross-section in tokamak devices.But elongated plasma has vertical displacement instability,so a feedback control system is needed to restrain the plasma's vertical displacement.A fast control power supply is needed to excite the active feedback coils,which produces a magnetic field to control the plasma's displacement.With the development of EAST,the fast control power supply needs to keep on enhancing the fast response and output current.The structure of a new power supply is introduced in this paper.The method of multiple inverters paralleled with the current sharing reactor is presented to meet the need for large current and fast control.According to the design demands of the EAST fast control power supply,the adjuster of the current close loop is applied to the inverter,which can advance its ability to restrain the loop current in low frequency and DC output.The result of the experiment confirms the validity of the proposed scheme and control strategy.
