Loading…
Modeling of screening currents in coated conductor magnets containing up to 40000 turns
Screening currents caused by varying magnetic fields degrade the homogeneity and stability of the magnetic fields created by REBCO coated conductor coils. They are responsible for the AC loss; which is also important for other power applications containing windings, such as transformers, motors and...
Saved in:
Published in: | Superconductor science & technology 2016-06, Vol.29 (8), p.85004 |
---|---|
Main Author: | |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | Screening currents caused by varying magnetic fields degrade the homogeneity and stability of the magnetic fields created by REBCO coated conductor coils. They are responsible for the AC loss; which is also important for other power applications containing windings, such as transformers, motors and generators. Since real magnets contain coils exceeding 10000 turns, accurate modeling tools for this number of turns or above are necessary for magnet design. This article presents a fast numerical method to model coils with no loss of accuracy. We model a 10400-turn coil for its real number of turns and coils of up to 40000 turns with continuous approximation, which introduces negligible errors. The screening currents, the screening current induced field (SCIF) and the AC loss is analyzed in detail. The SCIF is at a maximum at the remnant state with a considerably large value. The instantaneous AC loss for an anisotropic magnetic-field dependent Jc is qualitatively different than for a constant Jc, although the loss per cycle is similar. Saturation of the magnetization currents at the end pancakes causes the maximum AC loss at the first ramp to increase with Jc. The presented modeling tool can accurately calculate the SCIF and AC loss in practical computing times for coils with any number of turns used in real windings, enabling parameter optimization. |
---|---|
ISSN: | 0953-2048 1361-6668 |
DOI: | 10.1088/0953-2048/29/8/085004 |