Design of control system for quench protection unit in CRAFT project

Quench Protection Unit (QPU) is required to immediately control the high-power DC switch when the quench event occurs in the superconducting magnet. The energy in the magnet coil is quickly transferred to the Fast Discharge Resistor (FDR), which dissipates a large amount of stored energy and protects the magnet coil from damage. To ensure reliable protection of magnet coils, this paper proposes a design scheme of a soft-hard separation control system based on The Windows Control and Automation Technology (TwinCAT3). According to the high-power DC switch requirement for hundred-microsecond operation in QPU, this paper proposes a fast task priority cross-core scheduling algorithm. Tasks with short cycle times are prioritized and allocated to different cores. The experiment results demonstrate that the control system has excellent accuracy, speed, and reliability. Therefore, it can meet the high-power DC switch action requirements in QPU.