Magnetic Field in the Winding of an YBCO Pancake Coil: Experiments and Calculations

Polák, M.; Pardo, Enric; Mozola, P.; Šouc, J

doi:10.1109/tasc.2011.2178975

Cited by 10 publications

(5 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This method assumes the critical-state model in its most general condition, that is |J| can take any value lower or equal to J c [20,21]. The main developments to compute superconducting coils are in [22], the implementation of a field dependent J c in [23], interaction with linear magnetic materials in [24], and non-uniform tape properties in [25]. The present work assumes constant J c for simplicity.…”

Section: Methodsmentioning

confidence: 99%

Modeling of AC Loss in Coils Made of Thin Tapes Under DC Bias Current

Pardo¹

2014

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

Many applications, such as magnets and SMES, are usually charged and discharged under a bias DC current, which may increase the AC loss. For their design, it is necessary to understand and predict the AC loss. This article analises the AC loss in magnet-like coils under DC bias contribution super-imposed to the AC current. The analyses is based on a numerical model that takes the interaction between magnetization currents in all turns into account. The studied example is a stack of 32 pancake coils with 200 turns each made of thin tape, such as ReBCO coated conductor. We present the current density, the instantaneous power loss, and loss per cycle. We have found that the loss increases with the DC bias current. The instantaneous power loss is the largest in the initial rise of the the AC current. In following cycles, the power loss is higher in the current increase than in the decrease. The loss per cycle is the largest at the end pancakes. In conclusion, the highest cooling power should be supplied to the top and bottom pancakes and during current rise, specially the initial one. The presented model has a high potential to predict the AC loss in magnet-size coils, useful for their design.

show abstract

Section: Methodsmentioning

confidence: 99%

Modeling of AC Loss in Coils Made of Thin Tapes Under DC Bias Current

Pardo¹

2014

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

show abstract

“…We have cut three rectangular samples from the same section of the tape, two from the central part and one from the edge (figure 6). The cutting was done by a procedure described in [8] which does not markedly degrade the superconductor near the cuts.…”

Section: Inductive Measurement Of Critical Current Densitymentioning

confidence: 99%

“…Here we nevertheless investigate another aspect of superconductor non-uniformity. It was pointed out by several groups studying the AC loss that some of the experimental results could be explained assuming a variation of the critical current density across the tape width [5][6][7][8]. In other words, the critical current at the longitudinal location z = z 0 should be obtained by integrating the position-dependent sheet current density (2) across the tape width, w SC :…”

Section: Introductionmentioning

confidence: 99%

Non-uniformity of coated conductor tapes

Solovyov

Pardo

Šouc

et al. 2013

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Non-uniformity of superconductor properties, e.g. a critical current reduction close to the edge of a coated conductor (CC) tape could degrade its performance in some power applications. Reliable characterization of such non-uniformity and understanding of its mechanism requires investigation of the character and causes of degradation. In this paper spatial distribution of critical current density across the width of a CC tape is studied. Three different experimental methods allowing estimation of the local current density were utilized for this purpose: (i) magnetic field mapping above the tape through which a DC current is flowing, (ii) measurement of the critical current of separate strips prepared by patterning of the CC tape, and (iii) magnetization measurements of the pieces cut from various positions within the tape width. Very good agreement between the results obtained by these methods was found, showing a reduction of the critical current density at the tape edges with respect to its centre. Moreover, structural investigation by scanning electron microscopy revealed a correlation between the morphology and the critical current density across the tape width. Insertion of such real non-uniform distribution of critical current density into AC loss calculation resulted in a dramatic improvement in the agreement with experimental results.

show abstract

“…However, this simple scaling is often inaccurate, due to the fact that the critical current is not homogeneous across the width of the tape. The lateral inhomogeneity of the critical current across the tape width in coated-conductors has been reported and investigated in several articles [28][29][30][31][32][33]. Those studies showed that the central part of the tape has usually higher critical current than the lateral parts.…”

Section: Ic Measurement and Model Implementationmentioning

confidence: 99%

3D modeling and measurement of HTS tape stacks in linear superconducting magnetic bearings

Ghabeli,

Fuchs,

Hänisch

et al. 2024

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Superconducting magnetic bearings (SMBs) are among the possible new technologies to be incorporated in maglev vehicles. Stacks of HTS tapes can be used as an alternative to bulks, because stacks offer better mechanical properties, a better thermal conductivity and a simpler production process. Numerical modeling has been employed as a cost-effective, fast and reliable tool for improving the performance of SMBs. Several scenarios can be simulated with fast and relatively simple 2D models; however, in some cases using 3D models is inevitable. In this study, we use a full 3D model to solve the problem of magnetization of the tape stacks and obtaining the hysteresis force loop between a permanent magnet and the tape stacks. For this purpose, we employ an energy minimization-based method called MEMEP 3D, combined with a homogenization technique and the Jc(B,θ) dependence of the HTS tape as input. The modeling results agree very well with the experiment both in the zero-field cooled and field-cooled conditions. The presented approach offers significant computational advantages, delivering faster and more efficient results compared to previously proposed 3D methods.

show abstract

Magnetic Field in the Winding of an YBCO Pancake Coil: Experiments and Calculations

Cited by 10 publications

References 12 publications

Modeling of AC Loss in Coils Made of Thin Tapes Under DC Bias Current

Modeling of AC Loss in Coils Made of Thin Tapes Under DC Bias Current

Non-uniformity of coated conductor tapes

3D modeling and measurement of HTS tape stacks in linear superconducting magnetic bearings

Contact Info

Product

Resources

About