Experimental Study on Temperature-Controlled Charging Sequence for Reduction of Screening Current Effect in HTS Magnet

High-temperature superconductor (HTS) rare-earth barium copper oxide (REBCO) conductor has been extensively researched and developed for various applications. However, due to the intrinsic properties of REBCO conductors, the screening current occurs and this effect causes induced field and stress in superconducting magnets. Therefore, we investigated a strategy to mitigate the screening current effect in HTS magnets with the simultaneous control of temperature and current. In this paper, we ramped up the coil and measured the magnetic field of the HTS magnet as a references on conduction cooling system within different temperature: 20 K and 50 K. Then, the temperature-controlled charging sequence method with PID control was conducted so that the current ramping up simultaneously started with the magnet cool down: (1) 50 K to 20 K and (2) 80 K to 50 K. Finally, we analyzed the experiment results of the magnetic field distribution compared to reference charging values. These results showed the possibility to develop the operating techniques for high-field REBCO magnets that reduce the screening current induced field.