Design of variable-frequency power supply system based on multilevel inverters for dynamic resonant magnetic perturbation coils on J-TEXT tokamak

The dynamic resonant magnetic perturbation (DRMP) coils have been designed to study the feedback control of tearing mode (TM) instability in J-TEXT tokamak with rotating resonant magnetic perturbation. The AC power supply system energizing coils should have the ability of controlled current frequency in the range of 1 kHz to 5 kHz and amplitude of 5 kA peak value at 5 kHz. In further study, TM will be feedback controlled. In this paper, the main circuit of the variable-frequency power supply system with thyristor rectifier and cascaded H-bridges multilevel inverter is proposed. In order to adapt for the digital feedback control, a fast algorithm to calculate conduction angles of cascaded inverter is emphasized. Experimental results of the main circuit prototype are presented in the end of this paper.