Levitated Control and Simulation of Cat-1 Dipole Field Superconducting Magnet

Abstract: In response to the requirements of the dipole field plasma physics experiment for（CAT-1: China Astro Torus 1）, the device requires the center floating superconducting coil to be stably suspended for at least 5 hours without cooling and power supply conditions. A suspension control system for the coupling system of the superconducting lifting coil and the center floating coil was designed. To ensure the stable suspension of 1200kg and 5MA suspension magnets, the Simulink model of the control system was established and simulated. Based on the Routh Hurwitz stability criterion, the influence of PID control strategy on stable control was studied, and the range of stable control parameters was determined: when the power response frequency of the driving lifting coil should be greater than 9 Hz, and the error of the output current is less than 0.1%, the most effective control effect of the PD control system under ideal conditions is a delay time of 0.0463 seconds Rise time is 0.1545s, peak time is 0.6283s, adjustment time is 0.0848s, overshoot =1.6. The steady-state error err is less than 0.05mm, indicating that the corresponding frequency of the power supply is greater than 9Hz and the output error is less than 0.05%. The results show that based on PID, the suspended superconducting ring can be placed in the preset position in a short period of time, and under the appropriate starting method, the load of the circuit can be greatly reduced, providing strong support for the technical feasibility of the suspended superconducting dipole field device.