Wind turbine generators using superconducting coils and bulks

Ohsaki, Hiroyuki; Terao, Yutaka; Sekino, Masaki

doi:10.1088/1742-6596/234/3/032043

Cited by 20 publications

(13 citation statements)

References 7 publications

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“…Akin to YBa 2 Cu 3 O 7‐δ (YBCO) and (Rare‐Earth)Ba 2 Cu 3 O 7 (REBCO) cryomagnets, 8,9 bulk MgB 2 could be used for various applications such as the delivery of drug at specified locations in the human body using an external magnetic force, 10 magnetic separation systems, 11 portable nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) devices, 12 generators or motors 13,14 etc… For all these applications, the trapped magnetic field of present MgB 2 bulks must be improved. According to the Bean model, the trapped field is proportional to the critical current density, J c , and depends on the size of the persistent current loops, 15 that is linked to the sample size.…”

Section: Introductionmentioning

confidence: 99%

Improvement of critical current density of MgB₂ bulk superconductor processed by Spark Plasma Sintering

et al. 2020

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Spark Plasma Sintering (SPS) is a promising rapid consolidation technique that allows a better understanding and optimization of the sintering kinetics and therefore makes it possible to obtain MgB2 bulk superconductor with tailored microstructures consisting of grains with either spherical or elongated morphology. In this contribution, the role of the precursor powders on the superconducting properties of MgB2 is investigated. Three sets of bulk MgB2 material were processed from: (i) a commercially available MgB2 powder; (ii) a mixture of Mg metal and amorphous B using a single‐step solid‐state reaction process and (iii) a mixture of amorphous boron coated with carbon and Mg metal. The samples were prepared in the same SPS processing conditions. The microstructure of the samples was investigated by X‐ray diffraction, SEM and TEM and correlated to their superconducting properties. The critical current density of the best sample at 20K was Jc = 500 kA/cm2 in self‐field, which is one of the highest critical current density reported for MgB2 bulk superconductors.

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Section: Introductionmentioning

confidence: 99%

Improvement of critical current density of MgB₂ bulk superconductor processed by Spark Plasma Sintering

et al. 2020

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“…A trapped field over 2 T was successfully achieved at 6 K using an MgB 2 bulk (28 mm in diameter) synthesized under a pressure of 2 GPa [10]. Recently, research on MgB 2 bulk magnets has come into the spotlight again [11][12][13][14], because it is rare-earth free and light weight, in addition to weak-link-free, which makes them suitable for industrial applications, such as magnetically levitated trains, wind power generators, and so on [15]. We have reported that the trapped field was improved by densification, from 1.5 T for the MgB 2 bulk (the filling factor, f, was about 50%) fabricated by the capsule method under an ambient pressure [11], to 2.5 T for the bulk (f was higher than 90%) fabricated by a hot isostatic pressing (HIP) method under a pressure of 98 MPa [12]; the HIP method has been used to densify MgB 2 in many works [6,16,17].…”

Section: Introductionmentioning

confidence: 99%

Ti-doping effects on magnetic properties of dense MgB₂bulk superconductors

Naito¹,

Yoshida²,

Fujishiro³

2015

Supercond. Sci. Technol.

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We have studied the effects of Ti doping on the magnetic properties of MgB 2 superconducting bulks. The trapped field, which was obtained by field-cooled magnetization, B T FC , was about 3.6 T at 13 K at the surface of the single Ti5-20% doped MgB 2 bulks, which was about 1.3 times larger than that of the non-doped bulk. The B T FC of 4.6 T was achieved at 14.1 K in the centre of the doubly stacked Ti-doped MgB 2 bulks. The remanent magnetic flux density, which corresponds to the trapped field by zero-field cooled magnetization, B T ZFC , was comparable with the absolute value of coercive force with a very small vortex creep rate of about 2% over 40 h. These results suggested that the MgB 2 bulk was an excellent 'quasipermanent' magnet. The critical current density, J c , under magnetic field was also enhanced by Ti doping; under 3 T at 20 K, the J c of 4.0 10 3 × A cm −2 for the pristine sample was enhanced to that of 1.6-1.8 10 4 × A cm −2 for the Ti-doped samples. The irreversibility field exceeded 5 T at 20 K for the Ti-doped samples. The existence of nanometric unreacted B and strongly Mg-deficient Mg-B particles and TiB 2 layers at the periphery of Ti precipitates was suggested in the Ti-doped bulks by microscopic observation. The improvement of the vortex pinning properties in Ti-doped MgB 2 originated from the creation of the nanometric nonsuperconducting particles and TiB 2 layers acting as strong vortex pinning centres.

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“…MgB 2 bulk magnets have potential as quasi-permanent magnets that take place of oxide superconducting bulk magnets. It is expected to be applied for magnetic resonance imaging (MRI), motors and magnetically levitated trains [3], generator systems [4] in the future. Therefore, the trapped magnetic field of MgB 2 bulk magnet has been analyzed by the numerical calculation using finite element method (FEM).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Trapped Magnetic Field Properties in Superconducting MgB2 Bulk Magnets by Finite Element Method

et al. 2015

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The trapped magnetic field properties in superconducting MgB 2 bulk magnets with various kinds of shape such as a disk, a ring and a pair of disks were calculated by the finite element method (FEM). For simplicity, field cool magnetization was replaced by a simple magnetization process at constant temperature to obtain equivalent distribution of magnetic field, and the thermal equation in FEM was omitted. It was confirmed that the result of FEM agreed well with the result by analytical method in infinite long cylinder. We compared the trapped magnetic field property between FEM result and experimental result in reference in order to research the simple evaluation method of the trapped magnetic field of MgB 2 bulk magnet. It was found that the result of FEM agreed with the experimental result and it can explain the distribution of trapped magnetic field of superconducting MgB 2 bulk magnet. From these results, it was found that it was possible to be calculated in various kinds of shape with using simple evaluation by FEM. Therefore, the optimization of the maximum trapped magnetic field in superconducting MgB 2 bulk magnet can be discussed.

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Wind turbine generators using superconducting coils and bulks

Cited by 20 publications

References 7 publications

Improvement of critical current density of MgB₂ bulk superconductor processed by Spark Plasma Sintering

Improvement of critical current density of MgB₂ bulk superconductor processed by Spark Plasma Sintering

Ti-doping effects on magnetic properties of dense MgB₂bulk superconductors

Evaluation of Trapped Magnetic Field Properties in Superconducting MgB2 Bulk Magnets by Finite Element Method

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Wind turbine generators using superconducting coils and bulks

Cited by 20 publications

References 7 publications

Improvement of critical current density of MgB2 bulk superconductor processed by Spark Plasma Sintering

Improvement of critical current density of MgB2 bulk superconductor processed by Spark Plasma Sintering

Ti-doping effects on magnetic properties of dense MgB2bulk superconductors

Evaluation of Trapped Magnetic Field Properties in Superconducting MgB2 Bulk Magnets by Finite Element Method

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Product

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Improvement of critical current density of MgB₂ bulk superconductor processed by Spark Plasma Sintering

Improvement of critical current density of MgB₂ bulk superconductor processed by Spark Plasma Sintering

Ti-doping effects on magnetic properties of dense MgB₂bulk superconductors