Study of frequency dependent AC loss in Bi-2223 tapes used for gradient coils in magnetic resonance imaging

Yuan, Jing; Fang, Jin; Qu, Peng; Shen, Gary X.; Han, Z.

doi:10.1016/j.physc.2005.04.022

Cited by 16 publications

(4 citation statements)

References 12 publications

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“…This demonstrates the role of the frequency dependence of critical current in transport ac loss studies. Reference [34] has measured the frequency-dependent transport ac loss in Bi-2223 tapes and found it to decrease with increasing frequency. Norris' [32] equation for ac loss in a thin strip of superconductor is given by…”

Section: Transport Ac Lossmentioning

confidence: 99%

Frequency-dependent critical current and transport ac loss of superconductor strip and Roebel cable

Thakur¹,

Raj²,

Brandt³

et al. 2011

Supercond. Sci. Technol.

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The frequency-dependent critical current of a superconductor strip and Roebel cable has been studied using a 2D finite element simulation. It is shown that the critical current of the superconductor increases with frequency as f 1/n , where n is the exponent of the power law flux creep model. Transport ac loss in a superconductor strip decreases with frequency as f −2/n when the amplitude of the applied ac current is far less than its critical current. However, when the applied current is large and becomes comparable to the critical current, the transport ac loss decreases with frequency as 1/ f . The analytical results are substantiated with available experimental data and the results of a 2D finite element simulation.

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Section: Transport Ac Lossmentioning

confidence: 99%

Frequency-dependent critical current and transport ac loss of superconductor strip and Roebel cable

Thakur¹,

Raj²,

Brandt³

et al. 2011

Supercond. Sci. Technol.

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“…23,24 Further experimental and numerical results showed that this is because the hysteresis losses per cycle, which are dominant at very low frequencies, slightly decrease proportionally to the frequency. [25][26][27][28] Furthermore, Thakur et al 28 included the impact of the frequency-dependent critical current in the Norris equation for the hysteresis losses of a current-carrying thin strip. Supported by experimental data, they demonstrated that the hysteresis losses per cycle in fact decrease with the frequency as f −2/n (n being the exponent of the E-J power law) for ac currents well below the critical current and at low frequencies (maximum 400 Hz).…”

Section: Introductionmentioning

confidence: 99%

Transition frequency of transport ac losses in high temperature superconducting coated conductors

Zhou

Quéval

2019

Journal of Applied Physics

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Experimental data reveal that the classical description of transport ac losses in high-temperature superconducting (HTS)-coated conductors (CCs), based on investigations at low frequencies, is incomplete in some aspects when transport currents in the kilohertz range are considered. More specifically, above a certain "transition frequency," the ac losses per cycle no longer increase with the frequency as the theory predicts. Using a finite element model to allow for loss separation, we find that this phenomenon is caused by a combination of several factors that appear only above the transition frequency: the hysteresis and ferromagnetic losses per cycle are no longer independent of the frequency, while the eddy current losses per cycle no longer increase proportionally to the frequency. Based on a circuit model, we propose that the physical reason for this is that when the frequency increases, part of the supercurrent starts migrating into the metallic path. We argue that the current in the metallic path is not an eddy current but a transport current inductively coupled to the superconducting current. Finally, we discuss the relationship between the magnetic material magnetization, the critical current, and the transport current frequency. This study provides explicit insights into the frequency-dependent transport ac losses of HTS CCs in a broad frequency band, which is valuable for the design and optimization of HTS CC-based power devices.

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“…However, most applications of superconductor are operating at alternating current. Moreover, the AC current-carrying capability of superconductor has attracted extensive attention [1]- [7]. The transport AC current capacity is different from DC conditions since flux penetrated in and out of HTS with changing rate of magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Numerical Modeling and Experimental Analysis of AC Critical Current in YBCO-Coated Conductors

Liu

Zhang

et al. 2015

IEEE Trans. Appl. Supercond.

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Critical current is generally defined by the dc measurement at which current produces voltage of E c = 10 −4 Vm −1 . However, most applications of superconductor are operating at alternating current (ac). Moreover, the ac current-carrying capability of superconductor has attracted extensive attention. This paper is aimed to define the transport ac critical current and put forward a novel electric field criterion based on numerical modeling and experimental analysis. YBCO-coated conductor is investigated because of its power application potential and good anisotropy compared to Bi2223/Ag high-temperature superconductor. On measurement of I-V curves of YBCO-coated conductors at different frequency and liquid nitrogen temperature of 77 K, a novel criterion of transport ac critical current was proposed. Numerical modeling of finite element method was carried out, which was coincident with the experimental results.Index Terms-Alternate current capacity, frequency dependence, I-V curves, YBCO. 1051-8223

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Study of frequency dependent AC loss in Bi-2223 tapes used for gradient coils in magnetic resonance imaging

Cited by 16 publications

References 12 publications

Frequency-dependent critical current and transport ac loss of superconductor strip and Roebel cable

Frequency-dependent critical current and transport ac loss of superconductor strip and Roebel cable

Transition frequency of transport ac losses in high temperature superconducting coated conductors

Numerical Modeling and Experimental Analysis of AC Critical Current in YBCO-Coated Conductors

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