AC Loss Measurements on Multi-Filamentary $ \hbox{MgB}_{2}$ Wires With Non-Magnetic Sheath Materials

Taxt, Henning; Magnusson, Niklas; Runde, M.; Brisigotti, S.

doi:10.1109/tasc.2012.2231136

Cited by 10 publications

(6 citation statements)

References 19 publications

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“…(2) for large aspect ratios and, for a = 1 both B p and the losses attain the values derived for a round wire [25]. The model fits fairly well with results in the literature, e.g., [20,24] for BSCCO/Ag tapes and [26] for a round and a rectangular MgB 2 conductor using the dimensions of the cross-section of the elliptic filament region (not the entire conductor).…”

Section: Handling the Wire Geometry And Magnetic Field Orientationsupporting

confidence: 81%

Hysteresis losses in MgB 2 superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents

Magnusson

Abrahamsen

Liu

et al. 2014

Physica C: Superconductivity and its Applications

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a b s t r a c tMgB 2 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 MgB 2 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 MgB 2 DC coils in the 1-4 T range with low AC magnetic field and current ripples.

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Section: Handling the Wire Geometry And Magnetic Field Orientationsupporting

confidence: 81%

Hysteresis losses in MgB 2 superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents

Magnusson

Abrahamsen

Liu

et al. 2014

Physica C: Superconductivity and its Applications

Self Cite

View full text Add to dashboard Cite

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“…Various analytical models have been proposed in the literature to evaluate ac losses in multi-filamentary MgB 2 superconductors [38]- [41]. These approaches use conductor geometric properties and the applied field and current characteristics to estimate losses per unit volume.…”

Section: Methods To Evaluate Ac Loss With Harmonicsmentioning

confidence: 99%

Methods of Estimating AC Losses in Superconducting MgB$_{2}$ Armature Windings With Spatial and Time Harmonics

Balachandran

Salk²,

Lee³

et al. 2022

IEEE Trans. Appl. Supercond.

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Recent developments in low ac loss MgB 2 conductors are of significant importance given renewed interest in fully superconducting (SC) machines. Evaluating ac losses in fully SC machines is a critical step in developing feasible designs. In fully SC machines, SC armature windings experience non-uniform rotating magnetic fields, with spatial and temporal harmonics, which has an undisputed impact on ac losses. Existing ac loss models in the literature, which have been validated for stationary sinusoidal external fields, were extended to constant amplitude rotating fields. There is not enough research on validating the ac loss models for rotating non-uniform magnetic fields with harmonics. This paper proposes simplified methods to estimate the ac losses in conductors with non-uniform rotational applied magnetic fields experienced by the armature in a machine's environment. Extended analytical models are proposed to estimate the ac loss in single and multi-filament MgB 2 conductors. The models are then compared against finite element analysis (FEA) results with Power Law loss estimation to evaluate model fidelity.

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“…2 (b). When evaluating fully SC machine losses, the air-gap field is obtained from a detailed transient simulation, then analytical and FEA models are used on loss estimation [7], [27]- [31]. Carr's proposed ac loss models for stationary and uniform rotating fields to estimate losses in SC [12].…”

Section: Introductionmentioning

confidence: 99%

Instantaneous Loss Integration Method to Estimate AC Losses in Superconductors With Spatial and Time Harmonics

Balachandran

Haran

2023

IEEE Trans. Appl. Supercond.

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Estimating AC loss is an essential step in designing fully superconducting (SC) machines, which typically involves using analytical and Finite Element Analysis (FEA) models. Established analytical models are available for stationary sinusoidal and uniform rotating fields. But, the fully SC armature winding experiences a non-uniform rotating magnetic field that can result in varying losses. In this paper, we propose extended analytical methods to estimate AC losses in non-uniform rotating magnetic fields. Our proposed methods can refine the AC loss estimation process and improve the subsequent cryogenic load design. The significant advantage of our proposed method is the ability to capture the impact of AC losses due to varying field magnitude within a single cycle. We estimate losses for various scenarios and compare them to FEA analysis results to verify the accuracy of our model. We then experimentally validate the FEA models used in the analysis for uniformly rotating fields, which establishes the feasibility of our proposed models.

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AC Loss Measurements on Multi-Filamentary $ \hbox{MgB}_{2}$ Wires With Non-Magnetic Sheath Materials

Cited by 10 publications

References 19 publications

Hysteresis losses in MgB 2 superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents

Hysteresis losses in MgB 2 superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents

Methods of Estimating AC Losses in Superconducting MgB$_{2}$ Armature Windings With Spatial and Time Harmonics

Instantaneous Loss Integration Method to Estimate AC Losses in Superconductors With Spatial and Time Harmonics

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