Design of the power supply system for the plasma current modulation on J-TEXT tokamak

• A modification scheme of heating field power supply system for plasma current modulation.
• High-power fast control power supply with multilevel cascade circuit.
• Restraining circulating current with coupled inductors in cyclic symmetric structure.

In order to further study the influence of current modulation parameters on suppressing tearing instability, the plasma current should be modulated in a wider range. So a modification scheme is designed to improve the performance of ohmic heating power supply system on J-TEXT tokamak. A multilevel cascade circuit with carrier phase-shifted PWM technique has been proposed. Coupled inductors are connected in the form of cyclic symmetry to restrain the circulating current caused by multiple paralleled branches. The simulation proves this proposed current modulation power supply system matches output requirement and achieves good current sharing effect. Finally, a prototype is designed, and the experiment results can verify the correctness of the simulation model well.