3D simulations of total AC loss in a twisted multifilamentary MgB2 wire carrying AC currents under AC magnetic fields at 20 K

Yukai Qiao; Mark Ainslie; Yueming Sun; Matt Rindfleisch; Rodney A. Badcock; Nicholas M. Strickland; Zhenan Jiang

doi:10.1088/1361-6668/add42a

3D simulations of total AC loss in a twisted multifilamentary MgB₂ wire carrying AC currents under AC magnetic fields at 20 K

Yukai Qiao, Mark Ainslie, Yueming Sun, Matt Rindfleisch, Rodney A. Badcock, Nicholas M. Strickland, Zhenan Jiang^*

^*Corresponding author for this work

Engineering

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

12 Downloads (Pure)

Abstract

In the pursuit of enabling the application of all-superconducting rotating machines in electric aviation, high AC loss in the armature windings where superconductors carry AC currents and exposed to AC/rotating magnetic fields is a critical stumbling block. For lowering AC loss, multifilamentary magnesium diboride (MgB₂) wires with fine filaments and tight twist are one promising candidate for aviation applications. In this paper, 3D AC loss simulations of a 54-filament MgB₂ wire with a non-magnetic matrix at 20 K are carried out based on the H-formulation. The transport loss carrying AC current without external field, Q_t0, of 12-, 30- and 54-filament wires is firstly obtained, where the current amplitudes range from 20% to 90% of its self-field critical current I_c0. Then the magnetization loss exposed to field amplitudes up to 2 T without current, Q_m0, is presented, where the operational frequency, the twist pitch and resistivity of the matrix are varied to investigate their impacts on Q_m0 and its three loss components (hysteresis loss Q_h, coupling loss Q_c and eddy current loss Q_e). Lastly, the total loss, Q_total, of the 54-filament wire with various twist pitches and frequencies is compared, where the current amplitudes vary from 30% to 70% of I_c0 and the field amplitudes are up to 2 T. All simulations use the measured J_c(B, 20 K) and n(B, 20 K) data of the 54-filament wire. Simulation results show that, the use of the 5 mm twist pitch wire can significantly reduce Q_m0 due to the decoupling of the filaments, where the simulated Q_h matches well with the analytical hysteresis loss for a cylindrical superconductor multiplied by 54 (the number of filaments). With increasing twist pitch, the filaments become coupled, resulting in a greater increase in both Q_c and Q_h. Surprisingly, the simulated Q_total values in the wires with different twist pitches agree well with the sum of Q_m0 and Q_t0 for all different current levels. This implies that Q_total in an MgB₂ wire carrying an AC current exposed to an AC magnetic field can be accurately predicted by knowing Q_m0 and Q_t0 values which are more easily obtained.

Original language	English
Article number	055027
Journal	Superconductor Science and Technology
Volume	38
Issue number	5
DOIs	https://doi.org/10.1088/1361-6668/add42a
Publication status	Published - 15 May 2025

Keywords

all-superconducting rotating machines
coupling loss
hysteresis loss
magnetization loss
MgB2 wires
transport loss
total loss
3D modelling

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1088/1361-6668/add42aLicence: CC BY

SUST-106763 Accepted ManuscriptAccepted author manuscript, 2.53 MBLicence: CC BY

Cite this

@article{045314d30ff04dc5b5dd3c1265ff354d,

title = "3D simulations of total AC loss in a twisted multifilamentary MgB2 wire carrying AC currents under AC magnetic fields at 20 K",

abstract = "In the pursuit of enabling the application of all-superconducting rotating machines in electric aviation, high AC loss in the armature windings where superconductors carry AC currents and exposed to AC/rotating magnetic fields is a critical stumbling block. For lowering AC loss, multifilamentary magnesium diboride (MgB2) wires with fine filaments and tight twist are one promising candidate for aviation applications. In this paper, 3D AC loss simulations of a 54-filament MgB2 wire with a non-magnetic matrix at 20 K are carried out based on the H-formulation. The transport loss carrying AC current without external field, Qt0, of 12-, 30- and 54-filament wires is firstly obtained, where the current amplitudes range from 20% to 90% of its self-field critical current Ic0. Then the magnetization loss exposed to field amplitudes up to 2 T without current, Qm0, is presented, where the operational frequency, the twist pitch and resistivity of the matrix are varied to investigate their impacts on Qm0 and its three loss components (hysteresis loss Qh, coupling loss Qc and eddy current loss Qe). Lastly, the total loss, Qtotal, of the 54-filament wire with various twist pitches and frequencies is compared, where the current amplitudes vary from 30% to 70% of Ic0 and the field amplitudes are up to 2 T. All simulations use the measured Jc(B, 20 K) and n(B, 20 K) data of the 54-filament wire. Simulation results show that, the use of the 5 mm twist pitch wire can significantly reduce Qm0 due to the decoupling of the filaments, where the simulated Qh matches well with the analytical hysteresis loss for a cylindrical superconductor multiplied by 54 (the number of filaments). With increasing twist pitch, the filaments become coupled, resulting in a greater increase in both Qc and Qh. Surprisingly, the simulated Qtotal values in the wires with different twist pitches agree well with the sum of Qm0 and Qt0 for all different current levels. This implies that Qtotal in an MgB2 wire carrying an AC current exposed to an AC magnetic field can be accurately predicted by knowing Qm0 and Qt0 values which are more easily obtained.",

keywords = "all-superconducting rotating machines, coupling loss, hysteresis loss, magnetization loss, MgB2 wires, transport loss, total loss, 3D modelling",

author = "Yukai Qiao and Mark Ainslie and Yueming Sun and Matt Rindfleisch and Badcock, {Rodney A.} and Strickland, {Nicholas M.} and Zhenan Jiang",

note = "Publisher Copyright: {\textcopyright} 2025 The Author(s). Published by IOP Publishing Ltd.",

year = "2025",

month = may,

day = "15",

doi = "10.1088/1361-6668/add42a",

language = "English",

volume = "38",

journal = "Superconductor Science and Technology",

issn = "0953-2048",

publisher = "IOP Publishing Ltd.",

number = "5",

}

TY - JOUR

T1 - 3D simulations of total AC loss in a twisted multifilamentary MgB2 wire carrying AC currents under AC magnetic fields at 20 K

AU - Qiao, Yukai

AU - Ainslie, Mark

AU - Sun, Yueming

AU - Rindfleisch, Matt

AU - Badcock, Rodney A.

AU - Strickland, Nicholas M.

AU - Jiang, Zhenan

PY - 2025/5/15

Y1 - 2025/5/15

N2 - In the pursuit of enabling the application of all-superconducting rotating machines in electric aviation, high AC loss in the armature windings where superconductors carry AC currents and exposed to AC/rotating magnetic fields is a critical stumbling block. For lowering AC loss, multifilamentary magnesium diboride (MgB2) wires with fine filaments and tight twist are one promising candidate for aviation applications. In this paper, 3D AC loss simulations of a 54-filament MgB2 wire with a non-magnetic matrix at 20 K are carried out based on the H-formulation. The transport loss carrying AC current without external field, Qt0, of 12-, 30- and 54-filament wires is firstly obtained, where the current amplitudes range from 20% to 90% of its self-field critical current Ic0. Then the magnetization loss exposed to field amplitudes up to 2 T without current, Qm0, is presented, where the operational frequency, the twist pitch and resistivity of the matrix are varied to investigate their impacts on Qm0 and its three loss components (hysteresis loss Qh, coupling loss Qc and eddy current loss Qe). Lastly, the total loss, Qtotal, of the 54-filament wire with various twist pitches and frequencies is compared, where the current amplitudes vary from 30% to 70% of Ic0 and the field amplitudes are up to 2 T. All simulations use the measured Jc(B, 20 K) and n(B, 20 K) data of the 54-filament wire. Simulation results show that, the use of the 5 mm twist pitch wire can significantly reduce Qm0 due to the decoupling of the filaments, where the simulated Qh matches well with the analytical hysteresis loss for a cylindrical superconductor multiplied by 54 (the number of filaments). With increasing twist pitch, the filaments become coupled, resulting in a greater increase in both Qc and Qh. Surprisingly, the simulated Qtotal values in the wires with different twist pitches agree well with the sum of Qm0 and Qt0 for all different current levels. This implies that Qtotal in an MgB2 wire carrying an AC current exposed to an AC magnetic field can be accurately predicted by knowing Qm0 and Qt0 values which are more easily obtained.

AB - In the pursuit of enabling the application of all-superconducting rotating machines in electric aviation, high AC loss in the armature windings where superconductors carry AC currents and exposed to AC/rotating magnetic fields is a critical stumbling block. For lowering AC loss, multifilamentary magnesium diboride (MgB2) wires with fine filaments and tight twist are one promising candidate for aviation applications. In this paper, 3D AC loss simulations of a 54-filament MgB2 wire with a non-magnetic matrix at 20 K are carried out based on the H-formulation. The transport loss carrying AC current without external field, Qt0, of 12-, 30- and 54-filament wires is firstly obtained, where the current amplitudes range from 20% to 90% of its self-field critical current Ic0. Then the magnetization loss exposed to field amplitudes up to 2 T without current, Qm0, is presented, where the operational frequency, the twist pitch and resistivity of the matrix are varied to investigate their impacts on Qm0 and its three loss components (hysteresis loss Qh, coupling loss Qc and eddy current loss Qe). Lastly, the total loss, Qtotal, of the 54-filament wire with various twist pitches and frequencies is compared, where the current amplitudes vary from 30% to 70% of Ic0 and the field amplitudes are up to 2 T. All simulations use the measured Jc(B, 20 K) and n(B, 20 K) data of the 54-filament wire. Simulation results show that, the use of the 5 mm twist pitch wire can significantly reduce Qm0 due to the decoupling of the filaments, where the simulated Qh matches well with the analytical hysteresis loss for a cylindrical superconductor multiplied by 54 (the number of filaments). With increasing twist pitch, the filaments become coupled, resulting in a greater increase in both Qc and Qh. Surprisingly, the simulated Qtotal values in the wires with different twist pitches agree well with the sum of Qm0 and Qt0 for all different current levels. This implies that Qtotal in an MgB2 wire carrying an AC current exposed to an AC magnetic field can be accurately predicted by knowing Qm0 and Qt0 values which are more easily obtained.

KW - all-superconducting rotating machines

KW - coupling loss

KW - hysteresis loss

KW - magnetization loss

KW - MgB2 wires

KW - transport loss

KW - total loss

KW - 3D modelling

UR - http://www.scopus.com/inward/record.url?scp=105005203206&partnerID=8YFLogxK

U2 - 10.1088/1361-6668/add42a

DO - 10.1088/1361-6668/add42a

M3 - Article

SN - 0953-2048

VL - 38

JO - Superconductor Science and Technology

JF - Superconductor Science and Technology

IS - 5

M1 - 055027

ER -