Conceptual Design of the Power Supply for Magnetic Island Divertor Configuration on J-TEXT

The ac power supply system of the magnetic island divertor coil is widely applied to reduce the peak thermal load of the boundary target plate. It was found that this system should have the current frequency in the range of 0-100 Hz and the amplitude of 5 kA at 100 Hz. In this article, a new main circuit is proposed for the variable-frequency power supply system. The proposed circuit consists of a six-pulse, thyristor rectifier and a parallel, H-bridge inverter. The control strategy applies the carrier phase-shifted, sinusoidal pulsewidth modulation (CPS-SPWM) to form an almost sinusoidal current and calculate the LC filter parameters of the bus and inverter. Based on the requirements and load parameters of the power supply, it is found that the voltage and current double-closed loop PI control accelerates the system dynamic response and improves the nonlinear, load adaptability of the system. Moreover, the phase-shifting transformer with high-overload capability is applied in the proposed power supply to reduce the volume of the transformer and in advance charging. On the other hand, the water-cooling mode is adopted and the structure of water-cooled plate is designed. Moreover, optimal device and layout selection is performed to achieve reasonable modularization. Finally, the proposed method is applied to complete the main components of the space layout of the power supply. In the studied cases, the power density of 0.42 W/L is obtained.