Reference design of the power supply system for the resistive-wall-mode control in JT-60SA

•In JT-60SA, a power supply system (RWM-PS) will feed 18 coils to control the RWMs.•One power amplifier per coil will follow an arbitrary real-time reference.•Very fast dynamics is required (current bandwidth: 3kHz; latency: 50μs).•The requirements of the RWM-PS are updated and design solutions discussed.•The reference design of the RWM-PS is based on H-bridges operated at 20–30kHz. The mission of JT-60SA, the satellite Tokamak under construction in Naka (Japan), includes the attainment of steady-state high-beta plasmas. For this purpose, an active control system based on 18 in-vessel sector coils (SC) is foreseen to suppress the resistive wall modes (RWM). Each coil will be independently fed by a dedicated converter, rated for 300A and 240V, which has to produce the required current/voltage following in real time the reference provided by the JT-60SA MHD Controller. To minimize the current rating, these converters shall be sufficiently fast to avoid an excessive growth of the RWM. This requires a very high dynamic performance, largely beyond that of standard industrial applications. This paper firstly reports the latest results of the studies on the requirements of the RWM active control system. Then, the reference design of the power supply system is presented, including the ac/dc conversion stage, the fast converters and the control section. The advantages of the proposed scheme are discussed and the main electrical parameters are presented.