Experimental Study on AC Loss Reduction of HTS Coils by Use of Ferromagnetic Disks

Furuse, Mitsuho; Tanaka, Hideki; Kondoh, Junji; Umeda, M.

doi:10.1109/tasc.2004.830417

Cited by 14 publications

(10 citation statements)

References 1 publication

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“…However, the heat generated there will be the smallest. Another advantage of the fact that most of the AC loss is generated at the top and bottom of the coils is that it can be reduced by means of magnetic diverters [13,53,54,55].…”

Section: Ac Loss In Each Pancake Of a Stackmentioning

confidence: 99%

AC loss in ReBCO pancake coils and stacks of them: modelling and measurement

Pardo¹,

Šouc²,

Kováč³

2012

Supercond. Sci. Technol.

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Many applications of ReBCO coated conductors contain stacks of pancake coils. In order to reduce their high AC loss, it is necessary to understand the loss mechanisms. In this article, we measure and simulate the AC loss and the critical current, Ic, in stacks of pancake coils ("pancakes"). We construct stacks of up to 4 pancakes and we measure them by electrical means. We also obtain the anisotropic field dependence of Jc from Ic measurements of the tape. This Jc is the only input to the simulations, together with the coil dimensions. After validating our computations with the measurements, we simulate stacks of many pancakes, up to 32. We found that the AC loss in a stack of (four) pancakes is very high, two orders of magnitude larger than for a single tape. A double pancake behaves as a single one with double width but a stack of more pancakes is very different. Finally, we found that a 2-strand Roebel cable reduces the AC loss in a stack of pancakes but not in a single pancake. In conclusion, our simulations are useful to predict the ac loss of stacks of coated conductor pancake coils and to reduce the ac loss by optimizing the coil design.

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Section: Ac Loss In Each Pancake Of a Stackmentioning

confidence: 99%

AC loss in ReBCO pancake coils and stacks of them: modelling and measurement

Pardo¹,

Šouc²,

Kováč³

2012

Supercond. Sci. Technol.

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“…4 shows a plot of the losses for Coils D and Z against the product of the squared transport current and squared transport current frequency . The plots for the Coil Z lie on a similar curve, demonstrating that the total loss for Coil Z is dominated by mechanical loss, which is proportional to the product of the squared vibration frequency and the stored energy of the coil [3]. This suggests that the Zylon tape, which expands in the longitudinal direction in liquid nitrogen, causes the winding to loosen, introducing substantial mechanical loss.…”

Section: Sample Coils and Measurement Setupmentioning

confidence: 79%

“…As coils with high Young moduli generally exhibit lower mechanical loss [2], the present authors have developed a method to increase the rigidity of HTS coils by winding a nonmagnetic stainless steel tape together with an ordinary Bi2223/Ag tape with no cross-sectional reinforcement. Manuscript This configuration has been shown experimentally to reduce mechanical loss [3].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Loss of HTS Coils Reinforced With Negative Thermal Expansion Fiber Materials

Furuse

Umeda

Takao

et al. 2006

IEEE Trans. Appl. Supercond.

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High-c superconducting (HTS) coils with various types of reinforcement are investigated with respect to the reduction of mechanical loss. The total AC loss of the coils is measured under an external DC magnetic field at liquid nitrogen temperature, the reduction of the mechanical loss components are estimated. Tensioned stainless-steel tape is found to be the most effective for reducing the mechanical loss by improving the rigidity of the entire winding. The mechanical loss of the HTS coils is reduced by reinforcement with a bobbin of negative thermal expansion material, although the hoop stress caused by radial expansion of the bobbin is absorbed by a small number of winding turns. Bobbins of negative thermal expansion material are therefore unsuitable for pancake-type coils or multilayer windings, but can be expected to realize substantial reductions in mechanical loss for single-layer windings or thin solenoids.Index Terms-AC loss, HTS coil, mechanical loss, negative thermal expansion fiber materials.

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“…For this purpose, trapezoidal and circular cores/formers were used to wind coils in double-pancake configuration, and their electrical properties and characteristics were measured, experimentally. In [18], T AC loss of an HTS winding assembled by several doublepancake coils was measured. AC loss was reduced by placing a ferromagnetic disk near it.…”

Section: Introductionmentioning

confidence: 99%

Characterization of HTS Coils for Superconducting Rotating Electric Machine Applications: Challenges, Material Selection, Winding Process, and Testing

Messina

Yazdani-Asrami

Marignetti

et al. 2021

IEEE Trans. Appl. Supercond.

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The second-generation high temperature superconducting tapes (2G-HTS) such as the REBCO coated conductors (CC) are known for their strong mechanical properties and high current carrying capacity with low AC losses compared with first-generation HTS tapes as well as low temperature superconductors. Therefore, they seem to be good candidates to assemble coils for Superconducting Rotating Electric Machines (SuREMs). In this paper, to investigate influence of a Soft Magnetic Composite (SMC) material on the DC and AC HTS coil performances at cryogenic temperatures, GdBCO-and YBCO-based commercial tapes from different manufactures were used to assemble 10 HTS coils in doublepancake configuration. These tapes were wound using two different core structures, i.e. fixed and movable cores, having the same circular shape but different diameters as well as materials, i.e. fiberglass and SMC. Critical currents and AC transport current losses of these coils were measured using the electrical method. To evaluate the parallel and perpendicular components of the profile of magnetic flux density for each assembled HTS coil, a finite element model has been developed using Maxwell 2D. Eventually, the performance of different coils for SuREM application was discussed.

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Experimental Study on AC Loss Reduction of HTS Coils by Use of Ferromagnetic Disks

Cited by 14 publications

References 1 publication

AC loss in ReBCO pancake coils and stacks of them: modelling and measurement

AC loss in ReBCO pancake coils and stacks of them: modelling and measurement

Mechanical Loss of HTS Coils Reinforced With Negative Thermal Expansion Fiber Materials

Characterization of HTS Coils for Superconducting Rotating Electric Machine Applications: Challenges, Material Selection, Winding Process, and Testing

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