AC Loss and Macroscopic Theory of Superconductors

Carr, W. J.

doi:10.1201/9781482264760

Cited by 218 publications

(116 citation statements)

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“…Figure 5 shows the calculated cyclic losses as a function of the magnitude of the external field B 0 . The losses agree well with the approximate analytical expression by Carr [19]: where H 0 = B 0 /μ 0 and H p = 2RJ c /π. On a log-log scale like that of figure 5, one can observe a change of slope, from Q ≈ B 3 to Q ≈ B 1 , occurring when the field fully penetrates the superconductor.…”

Section: Round Superconductor In External Fieldsupporting

confidence: 86%

A numerical model to introduce students to AC loss calculation in superconductors

Grilli

Rizzo

2020

Eur. J. Phys.

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A numerical model implemented in the open-source finite-element method FreeFEM program is presented, with the aim of introducing students to the calculation of AC losses in superconductors. With this simple approach, students can learn about the critical state model used to describe the macroscopic electromagnetic behavior of superconductors and the importance of different factors influencing the AC losses of superconductors.

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Section: Round Superconductor In External Fieldsupporting

confidence: 86%

A numerical model to introduce students to AC loss calculation in superconductors

Grilli

Rizzo

2020

Eur. J. Phys.

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“…A small constant slope of the V-I curve for currents below the critical value is caused by the resistance of the joint point, of the order of 10 −6 ; this resistance can be estimated from the slope of the V-I curve for small currents. In the vicinity of the critical value, the better the homogeneity of the sample, the sharper the V-I dependence [12]. The critical current of the sample is nearly 150 A, while the critical current density is of the order of 10 4 A cm −2 .…”

Section: The V-i Curve and Critical Currents Of A Superconductormentioning

confidence: 95%

Digital storage oscilloscopes in the undergraduate laboratory

Kraftmakher¹

2012

Eur. J. Phys.

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Digital storage oscilloscopes (DSOs) are now easily available to undergraduate laboratories. In many cases, a DSO can replace a data-acquisition system. Seven such experiments/demonstrations are considered: (i) families of I–V characteristics of electronic devices (bipolar junction transistor), (ii) the V–I curve of a high-temperature superconductor (critical currents), (iii) the speed of electromagnetic waves and losses (in a coaxial cable), (iv) diffraction patterns (one and two slits), (v) the photoelectric effect (the Einstein equation), (vi) two variants of the Franck–Hertz experiment (with a Franck–Hertz tube from PHYWE and with a thyratron), and (vii) the structure of the video signal. All the experiments are performed without a computer or additional software. An exception is the experiment with a coaxial cable, where it is necessary to build graphs of the results obtained.

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“…Reliable loss estimation methods can help machine designers to design electrical machines optimally, and this paper contributes to this effort. Well-established analytical models for a stationary sinusoidal field [12]- [14] and Uniform rotating magnetic field [12], [15]- [19] are available in literature. Capturing the additional loss due to sinusoidal magnetic field with ac ripples has been attempted by various researchers [20]- [22].…”

Section: Introductionmentioning

confidence: 99%

“…When evaluating fully SC machine losses, the air-gap field is obtained from a detailed transient simulation, then analytical and FEA models are used on loss estimation [7], [27]- [31]. Carr's proposed ac loss models for stationary and uniform rotating fields to estimate losses in SC [12]. These models are used in [6], [9], [32], [33] to estimate machine losses.…”

Section: Introductionmentioning

confidence: 99%

Instantaneous Loss Integration Method to Estimate AC Losses in Superconductors With Spatial and Time Harmonics

Balachandran

Haran

2023

IEEE Trans. Appl. Supercond.

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Estimating AC loss is an essential step in designing fully superconducting (SC) machines, which typically involves using analytical and Finite Element Analysis (FEA) models. Established analytical models are available for stationary sinusoidal and uniform rotating fields. But, the fully SC armature winding experiences a non-uniform rotating magnetic field that can result in varying losses. In this paper, we propose extended analytical methods to estimate AC losses in non-uniform rotating magnetic fields. Our proposed methods can refine the AC loss estimation process and improve the subsequent cryogenic load design. The significant advantage of our proposed method is the ability to capture the impact of AC losses due to varying field magnitude within a single cycle. We estimate losses for various scenarios and compare them to FEA analysis results to verify the accuracy of our model. We then experimentally validate the FEA models used in the analysis for uniformly rotating fields, which establishes the feasibility of our proposed models.

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AC Loss and Macroscopic Theory of Superconductors

Cited by 218 publications

References 0 publications

A numerical model to introduce students to AC loss calculation in superconductors

A numerical model to introduce students to AC loss calculation in superconductors

Digital storage oscilloscopes in the undergraduate laboratory

Instantaneous Loss Integration Method to Estimate AC Losses in Superconductors With Spatial and Time Harmonics

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