Flux pumping, fluctuations and climbing fields

Coombs, Tim; Hadeler, O.; Zhang, M; Matsuda, Koichi

doi:10.1088/0953-2048/25/10/104007

Cited by 12 publications

(4 citation statements)

References 13 publications

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“…This may be due to the fact that with successive movements, there is a partial magnetization reversal of the CC-tapes. The magnetic flux is pumped into the CC-tape [29], which leads to a decrease in the levitation force at each cycle of motion. This effect was previously observed in levitation systems based both on bulk YBCO high-temperature superconductors [30,31] and in systems based on CC-tapes [8,9,15].…”

Section: Experimental Results and Their Discussionmentioning

confidence: 99%

Scalable superconductive magnetic bearing based on non-closed CC tapes windings

Osipov

Anishenko

Starikovskii

et al. 2021

Supercond. Sci. Technol.

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A new type of scalable high-temperature superconducting magnetic bearing is proposed. The bearing is based on the multilayer open windings made of coated conductor-tapes (CC-tapes). To demonstrate the possibility of manufacturing such a bearing construction we have built a working prototype and studied its characteristics. The manufactured model of bearing includes a stator, consisting of three multilayer rings (CC-tapes pancake coils) of 12 mm CC-tape and a composite rotor consisting of three rings of permanent magnets, each composed of 16 NdFeB 10 × 10 mm permanent magnets. We showed a contactless levitation of rotor relative to stator, as well as rotation of rotor and we measured load curves, namely the dependence of the rotor displacement on restoring force for axial and radial loads. Numerical simulation of bearing load characteristics has been carried out by the finite element method in the Comsol Multiphysics software. The calculation results are in a good agreement with the experimental data.

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Section: Experimental Results and Their Discussionmentioning

confidence: 99%

Scalable superconductive magnetic bearing based on non-closed CC tapes windings

Osipov

Anishenko

Starikovskii

et al. 2021

Supercond. Sci. Technol.

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“…This E(J) relation is then implemented into an electromagnetic numerical model. In this paper, we choose the 3D H-formulation model [68][69][70] established in the mfh module of the software COMSOL 6.0 based on the second-order curl element. The finite-element software package, COMSOL Multiphysics ® [71], enables an easy implementation of the Hformulation, and has been shown to be one of the most reliable computational methods to simulate electromagnetic fields of HTSs.…”

Section: Methodsmentioning

confidence: 99%

Study of the demagnetization behavior of no-insulation persistent-current mode HTS coils under external AC fields by 3D FEM simulation

Zhong,

Wu,

et al. 2024

Supercond. Sci. Technol.

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The no-insulation (NI) winding technique is promising to be applied in the persistent-current mode (PCM) operation of high-temperature superconducting (HTS) coils to provide those advantages. To apply the NI PCM coil, its demagnetization behaviour (i.e., decay of persistent DC current) by external AC field, which occurs in maglev trains, electric machines, and other dynamic magnet systems, is essential to be understood. For this purpose, a 3D FEM model, capturing the full electromagnetic properties of NI HTS coils, is established. This work has studied three kinds of AC fields, observing the impact of turn-to-turn contact resistivity on demagnetization rates, which is attributed to current distribution modulations. Under transverse AC field, the lower contact resistivity attracts more transport current to flow in the radial pathway to bypass the ‘dynamic resistance’ generated in the superconductor, leading to slower demagnetization. Under axial AC field, the demagnetization rate exhibits a non-monotonic relation with the contact resistivity: (1) the initial decrease of contact resistivity leads to concentration of induced AC current on the outer turns, which accelerates the demagnetization; (2) the further decrease of contact resistivity makes the current smartly redistribute to avoid to flow through the loss-concentrated outer turns, thus slowing down the demagnetization. Under the rotating DC field, a hybrid of the transverse and axial fields, the impact of contact resistivity on the demagnetization rate exhibits combined characteristics of the transverse and axial components. Besides, quantitative prediction on the demagnetization rate of NI PCM coil under external AC field is instructive for practical designs and operations, which is tried by this 3D FEM model, and a comparison with experimental result is conducted.

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“…Due to the flux pump [20] inside the YBCO bulks the levitation force was reduced drastically, as presented in Fig. 5.…”

Section: Slmb Dynamic Measurementsmentioning

confidence: 95%

A Full Scale Superconducting Magnetic Levitation (MagLev) Vehicle Operational Line

Sotelo

Oliveira

Costa

et al. 2015

IEEE Trans. Appl. Supercond.

154

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This paper describes the construction and main components of a full-scale superconducting magnetic levitation vehicle. The prototype, comprising four 1.5-m-long wagons, will travel a short test line of 200 meters, connecting two buildings inside the campus of the Federal University of Rio de Janeiro. The efforts to implement this technology started thirteen years ago with a small-scale prototype in an attempt to prove the concept. The second step was the construction of a functional prototype that could levitate more than one Ton. The actual stage of this project is the construction of an operational prototype mentioned above, designed to transport up to 24 passengers. This work has been reported in several previous editions of the ASC conference. New details about the elevated test line, the permanent magnetic (Nd-Fe-B) guideways, the cryostats with YBCO high critical temperature superconductors, the energy conditioning, the linear induction motor and its regenerative braking, as well as the automatic supply system of liquid nitrogen will be presented in the proposed paper. Tests with this operational prototype demonstrate the technology feasibility.

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Flux pumping, fluctuations and climbing fields

Cited by 12 publications

References 13 publications

Scalable superconductive magnetic bearing based on non-closed CC tapes windings

Scalable superconductive magnetic bearing based on non-closed CC tapes windings

Study of the demagnetization behavior of no-insulation persistent-current mode HTS coils under external AC fields by 3D FEM simulation

A Full Scale Superconducting Magnetic Levitation (MagLev) Vehicle Operational Line

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