AC loss in YBCO coated conductors at high dB/dt measured using a spinning magnet calorimeter (stator testbed environment)

Murphy, John P.; Gheorghiu, Nadina; Bullard, Thomas J.; Haugan, Timothy J.; Sumption, M.D.; Majoroš, M.; Collings, E. W.

doi:10.1016/j.cryogenics.2017.07.010

Cited by 10 publications

(13 citation statements)

References 35 publications

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“…Here we present the results in parallel, but do not attempt to compare them directly on a per amperage basis. The two cables described above were measured in a recently described SMC [28]. This test device has a spinning rotor which consists of a set of permanent magnets arranged in a Halbach array, with the sample exposed to a rotating AC field of 566 mT (peak) and a resulting dB/dt of 272 T s −1 for the radial component (tangential component B max = 242 mT, dB/dt = 125 T s −1 ).…”

Section: Samplesmentioning

confidence: 99%

“…These results combine high ramping rates with larger B max values on cables and are relevant to high impact HTS applications in superconducting motors and generators. To do this, we use a recently described spinning magnet calorimeter (SMC) [28]. This test device has a spinning rotor that consists of a set of permanent magnets arranged in a Halbach array, with the sample exposed to a rotating AC field of 566 mT (peak) and a resulting dB/dt of 272 T s −1 for the radial component (tangential component B max = 242 mT, dB/dt = 125 T s −1 ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

AC losses of Roebel and CORC^® cables at higher AC magnetic fields and ramp rates

Sumption¹,

Murphy²,

Haugan³

et al. 2021

Supercond. Sci. Technol.

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We have measured ReBCO coated conductor-based CORC® and Roebel cables at 77 K in a Spinning Magnet Calorimeter which subjected the tapes in the samples to a radial magnetic field of 566 mT (peak) at frequencies up to 120 Hz (272 T/s, cyclic average) with an approximately sinusoidal waveform. The samples were oriented such that the field applied to the tapes within the cables was entirely radial, simplifying subsequent analysis. An expression for loss which included hysteretic, flux creep, and eddy current losses was fit to both the CORC® and the Roebel cables. This expression allowed easy comparison of the relative influence of eddy currents and flux creep (or power-law behavior) effects. The loss of both the CORC® and Roebel cables measured here were seen to be essentially the sum of the hysteretic loss, flux creep effects, and the normal metal eddy current losses of the individual tapes. The losses of these cables were measured at high B*dB/dt with no coupling current loss observed under the present preparation conditions. The influence of flux creep effects on loss were not negligible. The losses of the CORC® cable per meter of tape were seen to be reduced from the case of a flat tape because of the helical geometry of the tapes.

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Section: Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

AC losses of Roebel and CORC^® cables at higher AC magnetic fields and ramp rates

Sumption¹,

Murphy²,

Haugan³

et al. 2021

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Apart from these works at low temperatures, the measurements in Refs. 26 , 27 at 77 K are highly remarkable. These experiments use a system that generates high magnetic inductions (more than 500 mT amplitude) at moderate frequencies, up to 200 Hz.…”

Section: Introductionmentioning

confidence: 96%

“…AC loss could be measured by two different techniques: calorimetric 6 , 15 , 21 , 26 , 27 or electric 12 – 16 , 18 , 19 , 21 – 25 . Electric measurements are more accurate than calorimetric, enabling to determine the AC loss also at low AC excitations.…”

Section: Introductionmentioning

confidence: 99%

Measurement of AC loss down to 25 K in a REBCO racetrack coil for electrical aircraft motor

Kováč

Kopera

Pardo

et al. 2022

Sci Rep

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The development of full superconducting motors for electric distributed aircraft propulsion requires to test the stator coils at the operation temperature, usually between 20 and 40 K. Here, we study the AC loss of a test racetrack coil made of REBCO tape. We developed a measurement system within a non-metallic cryostat where a cryocooler cools the test coil in combination with liquid or solid nitrogen. We present transport AC loss measurements by electrical means down to 25 K for current amplitudes up to 140 A and frequency 18–576 Hz. The AC loss increased with second power with current, and did not depend on frequency or temperature. Later, we measured the AC parallel magnetization loss in a stack of tapes made of the same material as the coil, and in a stack of tapes without superconducting layer. The results in both samples is almost identical and presents the same behavior as the coil. We conclude that the main contribution to the AC loss in the tape stack and in the coil was from the magnetism of the Hastelloy substrate or buffer layers. Therefore, researchers need to take this into account in tape production and in superconducting motor design.

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“…References [3][4][5][6][7] have experimentally researched the AC loss behavior of superconducting tapes under AC ripple superimposed on a DC offset current, providing useful guidance for the evaluation of AC losses when the DC and AC ripple currents exist simultaneously. References [8][9][10][11][12][13] provide some measuring methods of AC losses, but the applied frequencies of AC ripple currents are not typical in actual power systems. This paper aims to research experimentally AC ripple current losses of HTS tapes and the HTS cable for the common frequency range in the actual power system.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Simulation Research of AC Ripple Losses in a High Temperature Superconductor Tape

Liu

Song

Zhang

et al. 2018

Advances in Condensed Matter Physics

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Current leads in superconducting magnets are widely adopted for heavy current transmission, and HTS DC cables have great advantages when used as current leads for such purposes. However, as an important parameter of HTS DC cables, AC loss has a strong impact on the stability and operation cost of current leads. In this paper, experiments were conducted to measure AC ripple losses of HTS tapes and HTS cables, and simulations of HTS tapes were carried out. The paper has reached conclusions on the relation between AC losses and power frequencies.

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AC loss in YBCO coated conductors at high dB/dt measured using a spinning magnet calorimeter (stator testbed environment)

Cited by 10 publications

References 35 publications

AC losses of Roebel and CORC^® cables at higher AC magnetic fields and ramp rates

AC losses of Roebel and CORC^® cables at higher AC magnetic fields and ramp rates

Measurement of AC loss down to 25 K in a REBCO racetrack coil for electrical aircraft motor

Experimental and Simulation Research of AC Ripple Losses in a High Temperature Superconductor Tape

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AC loss in YBCO coated conductors at high dB/dt measured using a spinning magnet calorimeter (stator testbed environment)

Cited by 10 publications

References 35 publications

AC losses of Roebel and CORC® cables at higher AC magnetic fields and ramp rates

AC losses of Roebel and CORC® cables at higher AC magnetic fields and ramp rates

Measurement of AC loss down to 25 K in a REBCO racetrack coil for electrical aircraft motor

Experimental and Simulation Research of AC Ripple Losses in a High Temperature Superconductor Tape

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Product

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AC losses of Roebel and CORC^® cables at higher AC magnetic fields and ramp rates

AC losses of Roebel and CORC^® cables at higher AC magnetic fields and ramp rates