AC losses in HTS coils for high-frequency and non-sinusoidal currents

Bruyn, B.J.H. de; Jansen, J.W.; Lomonova, E.A.

doi:10.1088/1361-6668/aa7c74

Cited by 30 publications

(16 citation statements)

References 22 publications

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“…The vast majority of numerical models concentrate on the AC loss with standard sinusoidal AC transport current or magnetic fields. Although some simulation work of AC loss has considered both the DC background field, AC ripple field, and non-sinusoidal currents [127][128][129][130], the input signals for simulation are not real synthetic signals generated inside practical electrical machines. Consequently, the performance of HTS CCs under a complex synthetic electromagnetic environment deserves further exploration.…”

Section: Modelling Methodsmentioning

confidence: 99%

“…Time-domain periodical current, i(t), and voltage, u(t), can be expressed in the form of Fourier expansion, as [130]…”

Section: Electric Methodsmentioning

confidence: 99%

“…However, as pointed out in Section 3, the superconductors applied to electrical machines have to work with non-sinusoidal signals, namely, harmonics. De Bruyn et al have specified in [130] that the total AC loss is not always the result of a linear contribution of different harmonics when the transport current is not purely sinusoidal. Therefore, to measure the AC loss in superconducting machines, the conventional electric methods need to be improved.…”

Section: Electric Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Alternating Current Loss of Superconductors Applied to Superconducting Electrical Machines

Zhang¹,

Wen²,

Grilli

et al. 2021

Energies

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Superconductor technology has recently attracted increasing attention in power-generation- and electrical-propulsion-related domains, as it provides a solution to the limited power density seen by the core component, electrical machines. Superconducting machines, characterized by both high power density and high efficiency, can effectively reduce the size and mass compared to conventional machine designs. This opens the way to large-scale purely electrical applications, e.g., all-electrical aircrafts. The alternating current (AC) loss of superconductors caused by time-varying transport currents or magnetic fields (or both) has impaired the efficiency and reliability of superconducting machines, bringing severe challenges to the cryogenic systems, too. Although much research has been conducted in terms of the qualitative and quantitative analysis of AC loss and its reduction methods, AC loss remains a crucial problem for the design of highly efficient superconducting machines, especially for those operating at high speeds for future aviation. Given that a critical review on the research advancement regarding the AC loss of superconductors has not been reported during the last dozen years, especially combined with electrical machines, this paper aims to clarify its research status and provide a useful reference for researchers working on superconducting machines. The adopted superconducting materials, analytical formulae, modelling methods, measurement approaches, as well as reduction techniques for AC loss of low-temperature superconductors (LTSs) and high-temperature superconductors (HTSs) in both low- and high-frequency fields have been systematically analyzed and summarized. Based on the authors’ previous research on the AC loss characteristics of HTS coated conductors (CCs), stacks, and coils at high frequencies, the challenges for the existing AC loss quantification methods have been elucidated, and multiple suggestions with respect to the AC loss reduction in superconducting machines have been put forward. This article systematically reviews the qualitative and quantitative analysis methods of AC loss as well as its reduction techniques in superconductors applied to electrical machines for the first time. It is believed to help deepen the understanding of AC loss and deliver a helpful guideline for the future development of superconducting machines and applied superconductivity.

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Section: Modelling Methodsmentioning

confidence: 99%

“…Time-domain periodical current, i(t), and voltage, u(t), can be expressed in the form of Fourier expansion, as [130]…”

Section: Electric Methodsmentioning

confidence: 99%

Section: Electric Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Alternating Current Loss of Superconductors Applied to Superconducting Electrical Machines

Zhang¹,

Wen²,

Grilli

et al. 2021

Energies

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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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“…Also measured for comparison were the losses in the NbTi-based SC cable constructed to carry the same critical current at the same temperature. Figure 6 to be able to determine the AC power loss more accurately combining the cryogenic and electric measurement methods 34,35 .…”

mentioning

confidence: 99%

Record Fast-Cycling Accelerator Magnet Based on High-Temperature Superconductor [Poster]

Piekarz

Hays

Blowers

et al. 2019

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Four decades ago development of high-current superconducting NbTi wire cables revolutionized the magnet technology for energy frontier accelerators, such as Tevatron, RHIC and LHC. The NbTi based magnets offered advantage of much higher fields B and much lower electric wall plug power consumption if operated at 4.5 K but relatively small ramping rates dB/dt << 0.1 T/s. The need for the accelerators of high average beam power and high repetition rates have initiated studies of fast ramping SC magnets, but it was found the AC losses in the low-temperature superconductors preclude obtaining the rates in the excess of (1-4) T/s. Here we report the first application of high-temperature superconductor magnet technology with substantially lower AC losses and report record high ramping rates of 12 T/s achieved in a prototype dual-aperture accelerator magnet.Particle accelerators critically depend on development of high-field superconducting (SC) magnets 1,2,3 which allow to extend the energy reach and achieve desired cost and electric power efficiency of major physics facilities such as Tevatron at Fermilab 4 -the pioneering machne in operation from 1987 to 2011, Relativistic Heavy Ion Collider 5 (RHIC, 1999 -now) at Brookhaven National Laboratory, and Large Hadron Collider 6 (LHC) at CERN, Switzerland which operates since 2008. Note, that all these accelerators mostly operate in the regime of very slow beam energy ramp and their magnetic field ramping rates dB/dt are very low, 0.03 -0.07 T/s. Next generation facilities such as muon colliders 7,8 , future circular colliders 9 and high-intensity proton synchrotrons for neutrino research 10,11,12,13 accelerators demand substantially faster cycles of beam acceleration that in turn require fast cycling accelerator magnets with dB/dt of the order of tens to hundreds of T/s. Normal conducting magnets can provide such rates -for example the JPARC 3GeV proton rapid cycling synchrotron (RCS) magnets operate with dB/dt rates of 70 T/s 14 -but 1

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AC losses in HTS coils for high-frequency and non-sinusoidal currents

Cited by 30 publications

References 22 publications

Alternating Current Loss of Superconductors Applied to Superconducting Electrical Machines

Alternating Current Loss of Superconductors Applied to Superconducting Electrical Machines

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

Record Fast-Cycling Accelerator Magnet Based on High-Temperature Superconductor [Poster]

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