AC Loss Properties of Stacked REBCO Superconducting Tapes

Ueno, Tomoko; Iwakuma, Masataka; Ito, Tetsuya; Yun, K. W.; Adachi, Kazuhisa; Tomioka, Akihiro; Hase, Yoshiji; Konno, M.; Izumi, Teruo; Machi, T.; Ibi, A.

doi:10.1109/tasc.2017.2658118

“…The reason could be the eddy currents closing entirely within the soldering parts, which the model does not take into account. Another source of error could be inaccuracies in the superconducting loss calculation due to the (26). Others are numerical result calculated by equation ( 24): the green solid circle line is coupling loss Q R,numerical , the blue solid circle line is superconducting loss Q S .…”

Section: Frequency Dependencementioning

confidence: 99%

“…Although uncoupled stacks (and coils) and fully coupled stacks have been well studied by many researchers before, the case of an intermediate finite resistance ('partial coupling') has not been previously studied for stacks of tapes. Previous studies focused on AC loss under perpendicular magnetic field [20][21][22][23][24][25][26][27][28], AC loss under transport current [29][30][31][32][33], ac loss with consideration of ferromagnetic material [34][35][36][37], dynamic resistance under time-varying applied field [38][39][40][41], magnetization and decay of trapped magnetic field [42][43][44][45][46][47][48][49], multifilamentary calculations [20,50], among other topics.…”

Section: Introductionmentioning

confidence: 99%

Coupling loss at the end connections of REBCO stacks: 2D modelling and measurement

Li

¹

,

Kováč

²

,

Pardo

³

2020

Supercond. Sci. Technol.

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In high power density superconducting motors, superconducting tapes are usually stacked and connected together at terminals to improve the current capacity. When a parallel sinusoidal magnetic field is applied on this partially coupled stack, the coupling current is induced and causes additional coupling loss. Usually 3D modeling is needed to calculate the coupling loss but it takes too much computing resource and time. In this paper, a numerical 2D modeling by minimum electromagnetic entropy production (MEMEP) method is developed to speed up the calculation. The presented MEMEP model shows good accuracy and the capability to take the realistic resistance between tapes into account for coupling loss calculation with a high number of mesh element, which agrees to measurements.Thanks to the model, a systemic study of coupling loss on amplitude-dependence, frequency-dependence, resistance-dependence, and length-dependence, is presented and discussed. The results reveal the features of coupling loss which is very helpful devices with multi-tape conductors, such as the stator or rotor windings of motors.

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“…Many previous works have reported separate studies of magnetization loss [16][17][18][19][20][21][22][23][24] (under an AC magnetic field only) or dynamic resistance/loss [25][26][27][28] for HTS coated conductor single tape or stacks. These studies are incomplete to reveal the whole picture of dynamic resistance and total loss characteristics on account of the complex interaction between the DC current and the AC magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Dynamic resistance and total loss in a three-tape REBCO stack carrying DC currents in perpendicular AC magnetic fields at 77 K

Sun¹,

Fang²,

Sidorov³

et al. 2022

Supercond. Sci. Technol.

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In many high-temperature superconducting (HTS) applications, HTS coated conductors carry a DC current under an external AC magnetic field. In such operating conditions, dynamic resistance will occur when the traversing magnetic flux across the HTS conductors. Consequently, AC loss within the superconductors is composed of the dynamic loss component arising from dynamic resistance and the magnetization loss component due to the AC external magnetic field. In this work, the dynamic resistance and the total loss in a three-tape HTS coated conductor stack were measured at 77 K under perpendicular AC magnetic fields up to 80 mT and DC currents (Idc) up to the critical current (Ic). The stack was assembled from three serial-connected 4 mm wide Superpower wires. The measured dynamic resistance results for the stack were well supported by the results from 2D H-formulation finite element modelling (FEM) and broadly agree with the analytical values for stacks. The FEM analysis shows asymmetric transport DC current profiles in the central region of the superconductor. We attribute the result to the superposition of DC currents and the induced subcritical currents which explains why the measured magnetization loss values increase with DC current levels at low magnetic field. The onset of dynamic loss for the stack for low i (Idc/ Ic) values is much slower when compared to that of the single tape and hence the contribution of the dynamic loss component to the total loss in the stack is much smaller than that of the single tape. Dynamic loss in the stack becomes comparable to the magnetization loss at i = 0.5 and becomes greater than the magnetization loss at i = 0.7. Both magnetization loss and dynamic loss in the stack are smaller than those of the single tape due to shielding effects.

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“…Althgough, uncoupled stacks (and coils) and fully coupled stacks have been well studied by many researchers before, the case of an intermediate finite resistance ("partial coupling") has not been previously studied for stacks of tapes. Previous studes focused on ac loss under perpendicular magnetic field [19][20][21][22][23][24][25][26][27], ac loss under transport current [28][29][30][31][32], ac loss with consideration of ferromagnetic material [33][34][35][36], dynamic resistance under various applied field [37][38][39][40], magnetization and decay of trapped magnetic field [41][42][43][44][45][46][47][48], multifilamentary calculations [19,49], among other topics. Thanks to the presented numerical 2D MEMEP model, this article systematically studies and discusses the amplitude-dependence, frequency-dependence, and resistance-dependence of coupling loss under parallel magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Coupling loss at the end connections of REBCO stacks: 2D modelling and measurement

Li,

Pardo,

Kovac

2020

Preprint

0

View full text Add to dashboard Cite

In high power density superconducting motors, superconducting tapes are usually stacked and connected together at terminals to improve the current capacity. When a parallel sinusoidal magnetic field is applied on this partially coupled stack, the coupling current is induced and causes additional coupling loss. Usually 3D modeling is needed to calculate the coupling loss but it takes too much computing resource and time. In this paper, a numerical 2D modeling by minimum electromagnetic entropy production (MEMEP) method is developed to speed up the calculation. The presented MEMEP model shows good accuracy and the capability to take the realistic resistance between tapes into account for coupling loss calculation with a high number of mesh element, which agrees to measurements.Thanks to the model, a systemic study of coupling loss on amplitude-dependence, frequency-dependence, resistance-dependence, and length-dependence, is presented and discussed. The results reveal the features of coupling loss which is very helpful devices with multi-tape conductors, such as the stator or rotor windings of motors.

show abstract

AC Loss Properties of Stacked REBCO Superconducting Tapes

Cited by 13 publications

References 3 publications

Coupling loss at the end connections of REBCO stacks: 2D modelling and measurement

Coupling loss at the end connections of REBCO stacks: 2D modelling and measurement

Dynamic resistance and total loss in a three-tape REBCO stack carrying DC currents in perpendicular AC magnetic fields at 77 K

Coupling loss at the end connections of REBCO stacks: 2D modelling and measurement

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