Estimation of temperature rise from trapped field gradient on superconducting bulk magnetized by multi-pulse technique

Fujishiro, Hiroyuki; Naito, Tomoyuki; Kakehata, Kosuke; Yanagi, Yosuke; Itoh, Yoshitaka

doi:10.1088/0953-2048/23/2/025013

Cited by 5 publications

(2 citation statements)

References 15 publications

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“…The magnetization of 2G HTS bulks has been studied extensively, partly because it is one of the key challenges. Pulsed field magnetization (PFM) has been identified as an effective and practical way to magnetize 2G HTS bulks [10,11,12,13]. Due to the heat generated in the stack, the trapped field and flux acquired by PFM is usually less than that acquired by field cooling or zero field cooling methods, especially at lower temperatures [14,15].…”

Section: Introductionmentioning

confidence: 99%

A new ring-shape high-temperature superconducting trapped-field magnet

Sheng

Zhang

Wang

et al. 2017

Supercond. Sci. Technol.

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This paper presents a new type of trapped field magnet made of second generation high temperature superconducting (2G HTS) rings. This so-called ring-shape 2G HTS magnet has the potential to provide much stronger magnetic fields than existing permanent magnets. Compared to existing 2G HTS trapped field magnets, e.g. 2G HTS bulks and stacks, this new ring-shape 2G HTS magnet provides a promising technique to produce lager dimension magnets for industrial applications. This paper focuses on the working mechanism of this new structure magnet, both experimental and numerical study based on commercial magnetization techniques were carried out. Unique features have been identified and quantified for this new type of HTS magnet in field cooling and zero field cooling process. The magnetization mechanism is explained from the view of shielding and penetration of external magnetic field. An accumulation in the trapped field was observed by using multiple pulse field cooling. Besides, three types of demagnetization were also studies to ensure the practical properties of the ring-shape magnets. Conclusions obtained in this paper shows that this new ring-shape HTS magnet is very promising in trapping high magnetic field. As a super permanent magnet, it will have impacts in large-scale industrial applications, e.g. developing HTS machines with very high power density.

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Section: Introductionmentioning

confidence: 99%

A new ring-shape high-temperature superconducting trapped-field magnet

Sheng

Zhang

Wang

et al. 2017

Supercond. Sci. Technol.

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“…It has been experimentally proved that the multi-pulse technique can improve the trapped field of HTS bulks by PFM effectively. The multi-pulse techniques include successive pulsed-field application (SPA), iteratively magnetizing pulsed field method with reducing amplitude (IMRA), and multi-pulse technique with step-wise cooling (MPSC) [13], [14], [15], [16]. The increase of the trapped field by successive pulses is understood as a result of reducing temperature rise due to the existence of currents produced by previous pulses.…”

Section: Introductionmentioning

confidence: 99%

Simulation and experiments of stacks of high temperature superconducting coated conductors magnetized by pulsed field magnetization with multi-pulse technique

Zou

Zermeño

Baškys

et al. 2016

Supercond. Sci. Technol.

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High temperature superconducting (HTS) bulks or stacks of coated conductors (CCs) can be magnetized to become trapped field magnets (TFMs). The magnetic fields of such TFMs can break the limitation of conventional magnets (<2 T), so they show potential for improving the performance of many electrical applications that use permanent magnets like rotating machines. Towards practical or commercial use of TFMs, effective in situ magnetization is one of the key issues. The pulsed field magnetization (PFM) is among the most promising magnetization methods in virtue of its compactness, mobility and low cost. However, due to the heat generation during the magnetization, the trapped field and flux acquired by PFM usually cannot achieve the full potential of a sample (acquired by the field cooling or zero field cooling method). The multi-pulse technique was found to effectively improve the trapped field by PFM in practice. In this work, a systematic study on the PFM with successive pulses is presented. A 2D electromagnetic-thermal coupled model with comprehensive temperature dependent parameters is used to simulate a stack of CCs magnetized by successive magnetic pulses. An overall picture is built to show how the trapped field and flux evolve with different pulse sequences and the evolution patterns are analyzed. Based on the discussion, an operable magnetization strategy of PFM with successive pulses is suggested to provide more trapped field and flux. Finally, experimental results of a stack of CCs magnetized by typical pulse sequences are presented for demonstration.

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New application of temperature-dependent modelling of high temperature superconductors: Quench propagation and pulse magnetization

Zhang

Matsuda

Coombs

2012

Journal of Applied Physics

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We present temperature-dependent modeling of high-temperature superconductors (HTS) to understand HTS electromagnetic phenomena where temperature fluctuation plays a nontrivial role. Thermal physics is introduced into the well-developed H-formulation model, and the effect of temperature-dependent parameters is considered. Based on the model, we perform extensive studies on two important HTS applications: quench propagation and pulse magnetization. A micrometer-scale quench model of HTS coil is developed, which can be used to estimate minimum quench energy and normal zone propagation velocity inside the coil. In addition, we study the influence of inhomogeneity of HTS bulk during pulse magnetization. We demonstrate how the inhomogeneous distribution of critical current inside the bulk results in varying degrees of heat dissipation and uniformity of final trapped field. The temperature-dependent model is proven to be a powerful tool to study the thermally coupled electromagnetic phenomena of HTS.

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Estimation of temperature rise from trapped field gradient on superconducting bulk magnetized by multi-pulse technique

Cited by 5 publications

References 15 publications

A new ring-shape high-temperature superconducting trapped-field magnet

A new ring-shape high-temperature superconducting trapped-field magnet

Simulation and experiments of stacks of high temperature superconducting coated conductors magnetized by pulsed field magnetization with multi-pulse technique

New application of temperature-dependent modelling of high temperature superconductors: Quench propagation and pulse magnetization

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