Research on Current Sharing Control Strategy of CRAFT Rectifier Power Supply

Fast and stable control of the Comprehensive Research Facility for Fusion Technology (CRAFT) high-power rectifier power supply output current is an important guarantee for reliable plasma operation, and achieving current sharing control in each parallel branch is key to ensuring stable operation of the high-power rectifier power supply. The total output current feedback compensation control method is proposed to achieve fast and stable reference current tracking and branch current balance control in the high-power rectifier power supply. Based on independent current control in each rectifier bridge branch, the error of total current tracking reference current is used as the compensation factor to adjust each branch current in real time, ensuring branch current balance. The branch current balance tracking reference current further ensures the total output current tracking error being smaller. Independent tracking control of the branch current and compensation control of the total output current work together in the dynamic regulation process, and the control structure is simple and reliable. Simulation and practical engineering experiments of the CRAFT high-power rectifier power supply verify that the total output current can quickly and stably track the reference current output to 50 kA, effectively suppressing the circulating current for parallel branches and achieving a good current sharing effect for branches.