Magnetisation loss behaviour in insulated and non-insulated HTS REBCO double-pancake and racetrack coils at 77 K

TY - JOUR

T1 - Magnetisation loss behaviour in insulated and non-insulated HTS REBCO double-pancake and racetrack coils at 77 K

AU - Koshy, Ben George

AU - Bouloukakis, Konstantinos

AU - Ainslie, Mark

AU - Sun, Yueming

AU - Badcock, Rodney A.

AU - Mallett, Benjamin P. P.

AU - Jiang, Zhenan

N1 - Publisher Copyright: © 2025 The Author(s). Published by IOP Publishing Ltd.

PY - 2025/4/1

Y1 - 2025/4/1

N2 - In many high-temperature superconducting applications, the advantages of no-insulation (NI) coils, such as self-protecting capability and thermal stability, make them a promising alternative to insulated (INS) coils. Magnetisation loss will be generated when the coil is exposed to time-varying magnetic fields. This loss can vary with the applied field angle, magnitude, and frequency, resulting in parasitic heat loads. In this study, we investigate magnetization loss in NI and INS double-pancake and double-racetrack coils of identical dimensions, experimentally and numerically. Experiments were conducted at 77 K under external AC magnetic fields up to 100 mT, considering various field angles (0°-90°) and frequencies (73-146 Hz). The experimental results are compared with the finite element simulation results of the coils’ three-dimensional models. Interestingly, NI coils exhibit no significant angular dependence of loss within a specific field range; however, beyond this range loss increases with increasing field angles. In contrast, the loss in INS coils consistently increases with decreasing field angles across the entire field range. Coil level shielding of the magnetic field is observed in NI coils under parallel fields which is similar to a bulk superconductor. The losses in INS and NI coils are comparable under a perpendicular magnetic field, which can be attributed to the dominance of superconducting currents, as confirmed by the current and field distributions observed in simulations.

AB - In many high-temperature superconducting applications, the advantages of no-insulation (NI) coils, such as self-protecting capability and thermal stability, make them a promising alternative to insulated (INS) coils. Magnetisation loss will be generated when the coil is exposed to time-varying magnetic fields. This loss can vary with the applied field angle, magnitude, and frequency, resulting in parasitic heat loads. In this study, we investigate magnetization loss in NI and INS double-pancake and double-racetrack coils of identical dimensions, experimentally and numerically. Experiments were conducted at 77 K under external AC magnetic fields up to 100 mT, considering various field angles (0°-90°) and frequencies (73-146 Hz). The experimental results are compared with the finite element simulation results of the coils’ three-dimensional models. Interestingly, NI coils exhibit no significant angular dependence of loss within a specific field range; however, beyond this range loss increases with increasing field angles. In contrast, the loss in INS coils consistently increases with decreasing field angles across the entire field range. Coil level shielding of the magnetic field is observed in NI coils under parallel fields which is similar to a bulk superconductor. The losses in INS and NI coils are comparable under a perpendicular magnetic field, which can be attributed to the dominance of superconducting currents, as confirmed by the current and field distributions observed in simulations.

KW - magnetization loss

KW - HTS no-insulation coils

KW - HTS insulated coils

KW - HTS coil modelling

KW - angular dependence

UR - http://www.scopus.com/inward/record.url?scp=105000021637&partnerID=8YFLogxK

U2 - 10.1088/1361-6668/adbce2

DO - 10.1088/1361-6668/adbce2

M3 - Article

SN - 0953-2048

VL - 38

JO - Superconductor Science and Technology

JF - Superconductor Science and Technology

IS - 4

M1 - 045004

ER -