Vertical instability active controlled power supply of HL-3 tokamak

To mitigate plasma vertical instability and ensure high-quality physical experiments as well as the safety of the machine, the vertical instability active controlled power supply (VS PS) must respond rapidly to bias plasma vertical displacement events within the vacuum vessel. This paper presents the design of a cascaded H-bridge structure based on IGBT technology, marking the first implementation of a VS PS in the HL-3 tokamak. Unlike traditional power sources supplied by the grid, the VS PS is powered by a 300 MVA double Y six-phase motor-generator, which necessitates careful consideration of its unique supplying conditions. The modular design of the H-bridge allows for scalability to meet future demands for higher operational parameters. The cascaded H-bridge configuration enhances output voltage and reduces total harmonic distortion (THD) at the output side. The system effectively meets the control requirements for plasma vertical instability in the HL-3 tokamak, achieving a control response time of approximately 200 μs and managing plasma conditions under 1.6 elongation and 500 kA plasma current.