Trapped Field Characteristic of YBCO Bulk in AC External Magnetic Field

Ueda, Hiroshi; Ishiyama, Atsushi; Morisaki, T.

doi:10.1541/ieejpes.124.1357

Cited by 2 publications

(2 citation statements)

References 6 publications

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“…as well as analysing the power application systems [4][5][6][7]. However, the behaviour of the trapped magnetic flux in the bulk HTSs change complicatedly and nonlinearly depending on the operational conditions such as temperature and trapped field intensity.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, we consider that the percolation transition temperature can become the above-mentioned indicator. Some reports have been made about the relationship between the flux pinning property of a bulk HTS and T p [7,15]. However, as far as we know, no reports has been made which investigate their relationship strictly from a practical point of view.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Direct relationship between trapped magnetic flux characteristics and percolation transition temperature in a practical sized bulk high-temperature superconductor

Ogama¹,

Nakamura²

2006

Supercond. Sci. Technol.

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The trapped magnetic flux characteristics of a Gd-system bulk high-T c superconductor (HTS) near the so-called percolation transition temperature was investigated experimentally. The percolation transition temperature was directly determined from the temperature dependence of the E-J characteristics with a bar-shaped HTS. Next, the disc-shaped bulk HTS sample was magnetized by means of a field-cooling process, and then the decay of the trapped magnetic flux density was monitored for 30 min after the exciting current of the electromagnet was cut off. It was shown that the decay rate of trapped magnetic flux changed considerably around the percolation transition temperature. Furthermore, the trapped flux showed stepwise decay, and these phenomena could explain the percolation mechanism of the depinning process. From our study, the percolation temperature may be utilized for the limit parameter in order to design application systems with a practical sized bulk HTS.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Direct relationship between trapped magnetic flux characteristics and percolation transition temperature in a practical sized bulk high-temperature superconductor

Ogama¹,

Nakamura²

2006

Supercond. Sci. Technol.

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Motor structure and mechanical output density of IPM motor using bulk superconductors as magnetic field

Akada

Terao

Ohsaki

2019

J. Phys.: Conf. Ser.

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Recently, means of transportation with electrical motors such as electric vehicles and ships are rapidly increasing. Various attempts have been made to reduce the size of the motors to increase the freedom of transport equipment system layouts and the energy efficiency of their transportation. Interior permanent magnet synchronous motors (IPMSMs) can realize higher torque than surface permanent magnet synchronous motors (SPMSMs) by using reluctance torque caused by magnetic saliency in addition to magnet torque. In comparison with SPMSMs, IPMSMs can have wide operation ranges by applying control methods such as maximum output control and field weakening control. Therefore, IPMSMs are expected to be used for a variety of application such as electric vehicles, ships and heavy equipment. By replacing permanent magnets with bulk superconductors in the rotors of IPMSMs, the magnet torque increases due to the stronger magnetic field of magnetized bulk superconductors. This leads to an increase in total torque density of the motors and contributes to motor size reduction. In this research, we propose an IPMSM with bulk superconductors with the goal of increasing the mechanical output density. In the proposed IPMSM, cooling space is left inside the rotor to cool the bulk superconductors to their superconducting state. Here, analysis based on finite element method was carried out to verify the utility of the proposed motor. First, the design of the motor with bulk superconductors and cooling space is discussed. It is shown that the total torque can be increased by adjusting the position of the bulk superconductor and modifying the structure of the flux barrier. The maximum total torque shown here was 22500 Nm. Then, the mechanical output density of the proposed IPMSM is compared with a conventional IPMSM. It is shown that the mechanical output density of the proposed IPMSM is 38% higher than the conventional IPMSM. Finally, the magnetic shielding effect, which might be a problem when using bulk superconductors, is discussed. By using electromagnetic analysis, it is shown that the external magnetic flux is weakened by the cooling space to several percent of the magnets’ surface and the effect of the shielding current is trivial.

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Trapped Field Characteristic of YBCO Bulk in AC External Magnetic Field

Cited by 2 publications

References 6 publications

Direct relationship between trapped magnetic flux characteristics and percolation transition temperature in a practical sized bulk high-temperature superconductor

Direct relationship between trapped magnetic flux characteristics and percolation transition temperature in a practical sized bulk high-temperature superconductor

Motor structure and mechanical output density of IPM motor using bulk superconductors as magnetic field

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