AC Loss Evaluation of NI REBCO Pancake Coils in External Low-Frequency Magnetic Field

• Published in: IEEE transactions on applied superconductivity Vol. 32; no. 6; pp. 1 - 5
• Main Authors: Daiho, Kazuhiro, Ishiyama, Atsushi, Noguchi, So
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-09-2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: AC loss; Aircraft propulsion; Barium; Coils; Conductivity; Copper oxides; Equivalent circuits; Field coils; joule loss; Magnetic fields; Magnetic hysteresis; Magnetic resonance imaging; Magnetism; magnetization loss; no-insulation winding technique; Pancake coils; Rare earth elements; REBCO magnet; Synchronous motors; Thermal stability
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2022.3191297

No-insulation (NI) rare-earth barium copper oxide (REBCO) pancake coils have attracted much attention because of their high thermal stability. It is, therefore, expected to apply NI REBCO pancake coils to various applications. In recent years, there have been discussions on the possibility of applying NI REBCO pancake coils to field coils of synchronous motors for ship and aircraft propulsion. NI REBCO field coils would be exposed to an AC magnetic field of ∼1 Hz. The AC losses must be discussed because a current is induced in an NI REBCO coil under externa AC field. AC losses in NI REBCO pancake coils exposed to changing magnetic fields should be investigated in detail. In this paper, the AC Joule loss of the NI-REBCO pancake coils is investigated by simulation using a partial element equivalent circuit (PEEC) model. The magnetization loss is also investigated based on the Bean model when a low-frequency AC magnetic field is applied to the NI REBCO pancake coil. From the simulation results, we concluded a high contact resistivity can sufficiently reduce the Joule loss.