The Feedback Control of the −200 kV High Voltage Power Supply for CRAFT NNBI

The −200 kV high-voltage power supply serves as the acceleration power supply for the Comprehensive Research Facility for Fusion Technology neutral beam injector (CRAFT NNBI) system, and its operation entails strict requirements to ensure its dynamic and steady-state performance. This article proposes a power supply topology for its application based on phase-controlled rectification, a three-level NPC inverter, a boost converter transformer, and high-voltage uncontrollable rectification (AC-DC-AC-DC). This topology provides a structural advantage by enabling control functionality on the low-voltage side, thereby eliminating the need for control functions on the high-voltage side. The boost converter transformer ensures electrical isolation between the high-voltage and low-voltage sides, while the precise control of the output voltage is coordinated by the phase-controlled rectifier and NPC inverter. Coarse adjustment is achieved through regulation of the DC bus voltage while the duty cycle of the NPC can be adjusted for fine-tuning. The quality of the DC output voltage is controlled through a combination of phase-controlled rectification and the NPC inverter to ensure the stability, accuracy, and ripple requirements of the final high-voltage DC side. This article also provides a detailed analysis of the hardware selection and feedback control of the system through a simulation of the power supply using MATLAB/Simulink software. The experimental tests and simulation results consistently indicated that the power supply meets the stability and dynamic response requirements necessary for the CRAFT NNBI system’s implementation.