Hysteresis losses in MgB2 superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents

N. Magnusson, Asger Bech Abrahamsen, Dawei Liu, M. Runde, H. Polinder

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

MgB2 superconductors are considered for generator field coils for direct drive wind turbine generators. In such coils, the losses generated by AC magnetic fields may generate excessive local heating and add to the thermal load, which must be removed by the cooling system. These losses must be evaluated in the design of the generator to ensure a sufficient overall efficiency. A major loss component is the hysteresis losses in the superconductor itself. In the high DC – low AC current and magnetic field region experimental results still lack for MgB2 conductors. In this article we reason towards a simplified theoretical treatment of the hysteresis losses based on available models in the literature with the aim of setting the basis for estimation of the allowable magnetic fields and current ripples in superconducting generator coils intended for large wind turbine direct drive generators. The resulting equations use the DC in-field critical current, the geometry of the superconductor and the magnitude of the AC magnetic field component as parameters. This simplified approach can be valuable in the design of MgB2 DC coils in the 1–4T range with low AC magnetic field and current ripples.
Original languageEnglish
JournalPhysica C: Superconductivity and its Applications
Volume506
Pages (from-to)133-137
ISSN0921-4534
DOIs
Publication statusPublished - 2014

Keywords

  • Generator field winding
  • Ac losses
  • Magnesiumdiboride

Cite this

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title = "Hysteresis losses in MgB2 superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents",
abstract = "MgB2 superconductors are considered for generator field coils for direct drive wind turbine generators. In such coils, the losses generated by AC magnetic fields may generate excessive local heating and add to the thermal load, which must be removed by the cooling system. These losses must be evaluated in the design of the generator to ensure a sufficient overall efficiency. A major loss component is the hysteresis losses in the superconductor itself. In the high DC – low AC current and magnetic field region experimental results still lack for MgB2 conductors. In this article we reason towards a simplified theoretical treatment of the hysteresis losses based on available models in the literature with the aim of setting the basis for estimation of the allowable magnetic fields and current ripples in superconducting generator coils intended for large wind turbine direct drive generators. The resulting equations use the DC in-field critical current, the geometry of the superconductor and the magnitude of the AC magnetic field component as parameters. This simplified approach can be valuable in the design of MgB2 DC coils in the 1–4T range with low AC magnetic field and current ripples.",
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author = "N. Magnusson and Abrahamsen, {Asger Bech} and Dawei Liu and M. Runde and H. Polinder",
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doi = "10.1016/j.physc.2014.06.012",
language = "English",
volume = "506",
pages = "133--137",
journal = "Physica C: Superconductivity and its Applications",
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Hysteresis losses in MgB2 superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents. / Magnusson, N.; Abrahamsen, Asger Bech; Liu, Dawei; Runde, M.; Polinder, H.

In: Physica C: Superconductivity and its Applications, Vol. 506, 2014, p. 133-137.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Hysteresis losses in MgB2 superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents

AU - Magnusson, N.

AU - Abrahamsen, Asger Bech

AU - Liu, Dawei

AU - Runde, M.

AU - Polinder, H.

PY - 2014

Y1 - 2014

N2 - MgB2 superconductors are considered for generator field coils for direct drive wind turbine generators. In such coils, the losses generated by AC magnetic fields may generate excessive local heating and add to the thermal load, which must be removed by the cooling system. These losses must be evaluated in the design of the generator to ensure a sufficient overall efficiency. A major loss component is the hysteresis losses in the superconductor itself. In the high DC – low AC current and magnetic field region experimental results still lack for MgB2 conductors. In this article we reason towards a simplified theoretical treatment of the hysteresis losses based on available models in the literature with the aim of setting the basis for estimation of the allowable magnetic fields and current ripples in superconducting generator coils intended for large wind turbine direct drive generators. The resulting equations use the DC in-field critical current, the geometry of the superconductor and the magnitude of the AC magnetic field component as parameters. This simplified approach can be valuable in the design of MgB2 DC coils in the 1–4T range with low AC magnetic field and current ripples.

AB - MgB2 superconductors are considered for generator field coils for direct drive wind turbine generators. In such coils, the losses generated by AC magnetic fields may generate excessive local heating and add to the thermal load, which must be removed by the cooling system. These losses must be evaluated in the design of the generator to ensure a sufficient overall efficiency. A major loss component is the hysteresis losses in the superconductor itself. In the high DC – low AC current and magnetic field region experimental results still lack for MgB2 conductors. In this article we reason towards a simplified theoretical treatment of the hysteresis losses based on available models in the literature with the aim of setting the basis for estimation of the allowable magnetic fields and current ripples in superconducting generator coils intended for large wind turbine direct drive generators. The resulting equations use the DC in-field critical current, the geometry of the superconductor and the magnitude of the AC magnetic field component as parameters. This simplified approach can be valuable in the design of MgB2 DC coils in the 1–4T range with low AC magnetic field and current ripples.

KW - Generator field winding

KW - Ac losses

KW - Magnesiumdiboride

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DO - 10.1016/j.physc.2014.06.012

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JO - Physica C: Superconductivity and its Applications

JF - Physica C: Superconductivity and its Applications

SN - 0921-4534

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