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

Magnusson, Niklas; Abrahamsen, Asger Bech; Liu, Dong; Runde, M.; Polinder, H.

doi:10.1016/j.physc.2014.06.012

Cited by 15 publications

(6 citation statements)

References 28 publications

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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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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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show abstract

“…To achieve the required overall system efficiency of 85% for WPT-systems [12], the losses in the coils must be reduced. The losses generated by the HTS coils are extremely high for LF and frequencies targeted by such systems, particularly taking into account that the operating temperature is 77 K. To minimise the impact of the skin effect, other materials such as MgB 2 are used in superconducting applications, which allows reduced AC losses due to its multifilament structure [30][31][32][33]. However, there is no literature on the use of MgB 2 in the frequency range used in WPT, which makes it difficult to gauge feasibility.…”

Section: Ac Transport Current Lossmentioning

confidence: 99%

Loss characteristics of superconducting pancake, solenoid and spiral coils for wireless power transfer

Machura

Zhang

Kails

et al. 2020

Supercond. Sci. Technol.

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Wireless power transfer (WPT) is an emerging technology with widespread applications, such as wireless charging for electric vehicles (EVs), which has become a major point of interest. Conventionally, it is used for stationary charging, but also dynamic systems emerge. Key drawbacks of standard WPT systems are the limited transfer distance between the copper coils and the transfer efficiency. By employing high-temperature superconductors (HTS) as coil material these limitations can be alleviated. However, HTS coils have highly nonlinear ac loss characteristics, which will be studied. This paper investigates the transport current loss and the magnetisation loss of HTS coils individually and when combined in the high frequency range relevant to WPT for EVs. A multilayer 2D axisymmetric coil model based on H -formulation is proposed and validated by experimental results as the HTS film layer is inapplicable at such frequencies. Three of the most commonly employed coil configurations, namely: double pancake, solenoid and circular spiral are examined. While spiral coils experience the highest transport current loss, solenoid coils are subject to the highest magnetisation loss due to the overall distribution of the turns. Furthermore, a transition frequency is defined for each coil when losses in the copper layer exceed the HTS losses. It is much lower for coils due to the interactions between the different turns compared to single HTS tapes. At higher frequencies, the range of magnetic field densities, causing a shift where the highest losses occur, decreases until losses in the copper stabilisers always dominate. In addition, case studies investigating the suitability of HTS-WPT are proposed.

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“…The AC loss in SC winding consists of magnetic hysteresis loss P h and eddy-current loss P e , as can be expressed from (2)-(5), [13]- [15].…”

Section: Loss Analysis and Efficiencymentioning

confidence: 99%

Comparison of Electromagnetic Performance of SCPM Wind Power Generators With Different Topologies

Huang

Zhou

Zhang

et al. 2019

IEEE Trans. Appl. Supercond.

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This paper mainly focuses on the comparison of electromagnetic performance of the superconducting permanent magnet (SCPM) generators with two different topologies. The torque capabilities of the two generators are first investigated. The peak torque is largely restricted by the material characteristics of the SC and the permanent magnet (PM). It turns out that the SCPM generators with iron-cored rotor and iron-cored stator topology (IRIST) is superior to the one with iron-cored rotor and air-cored stator topology (IRAST) in terms of torque capability. Furthermore, the flux density, line electromotive force (EMF), torque and its torque ripple, and the efficiency of the designed generators are evaluated by using numerical model. The simulation results confirm that IRIST has higher output torque and efficiency with the penalty of higher harmonics and torque ripples.  Index Terms-Finite element method (FEM); superconducting permanent magnet wind power generator; topology; comparison

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

Cited by 15 publications

References 28 publications

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

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

Loss characteristics of superconducting pancake, solenoid and spiral coils for wireless power transfer

Comparison of Electromagnetic Performance of SCPM Wind Power Generators With Different Topologies

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