Development of the Magnet Coil Power Supply for Fishtail Divertor on EAST

Fishtail divertor (FTD), a new divertor concept, is a significant research object of Experimental Advanced Superconducting Tokamak (EAST) tokamak divertor system. In order to meet the requirement of sinusoidal current precision and variable frequency, the combination of inductance and capacitance (
LC
) series resonance theory and high-frequency pulsewidth modulation (PWM) technology is put forward. A sine wave power supply with multifrequency points (1–3800 Hz) and current up to 8000 A is developed. The FTD power supply (PS) adopts dc switching power technology, sinusoidal PWM (SPWM) technology, and
LC
series resonance theory. The operating points of output current include 10–20 Hz at 8000 A, 30–110 Hz at 5000 A, and 1300–3800 Hz at 2400 A. The electromagnetic environment in the device is complex and arguable. The output current accuracy can reach 5% by the current feedback and frequency feedback control strategy. The test results demonstrate that the FTD PS can meet the system requirements, and it has strong reference significance, which can provide reference for the design of other divertor PS.