Design and Analysis of Power Supply System for EAST In-Vessel Down Divertor Coil

EAST (Experimental Advanced Superconducting Tokamak) requires the use of in-vessel down divertor coil to realize quasi-snowflake, FTD (Fishtail Divertor) and detachment of plasma. The required current of the down divertor coil is up to dc 20kA and ac 30kA with adjustable frequency from 5 to 100Hz. The response time is less than 1ms, the current rise rate is more than 10kA/ms, and the power factor is unity or high. This paper describes a topology design through analyzing three different high-power topologies. The carrier phase-shift modulation method (CPS-PWM) is applied to solve the contradiction of high-power switch devices between output high current capability, fast response speed and low output ripple. The advantages and feasibility of the proposed design have been verified by simulation using MATLAB.