Development of a Complete Power Supply System With Control and Quench Protection for the HFRS Superconducting DC Dipole Magnet

Abstract

The high-energy fragment separator (HFRS) at the high-intensity heavy-ion accelerator facility (HIAF) employs 11 superferric superconducting dipole magnets to deflect heavy-ion beams. Operating at a design current of 210 A and storing 370 kJ of magnetic energy, each magnet requires a dedicated DC power supply capable of providing highly stable excitation current and fast quench protection. This article presents a complete power supply system for these magnets, with particular emphasis on a modular quench protection module (QPM) and an FPGA-based centralized controller. The QPM adopts a redundant full-bridge IGBT architecture in a compact 4U form factor. Upon receiving magnet quench trigger signals via a fiber optic interface, it completes IGBT turn-off and energy extraction circuit engagement within a microsecond-scale response time, thereby enabling fast and reliable magnet protection. The FPGA main controller incorporates a masking communication mechanism, which provides centralized management, independent control, and real-time diagnosis of magnet quench and module faults for distributed power units. Through a serial device server, the centralized controller simultaneously monitors the operating status and configures parameters for up to six power supply units over RS-485 links. Experimental results confirm that the power supply achieves a current stability of $\pm 1 \times 10^{-4}$ . Under simulated magnet quench conditions, the protection system successfully transfers the stored energy to an external dump resistor, validating the reliability and effectiveness of the proposed scheme. The system provides a scalable protection solution for the HFRS superconducting dipole magnet array.