A novel no-insulation winding technique of high temperature-superconducting racetrack coil for rotating applications: A progress report in Korea university

Choi, Yoon Hyuck; Song, Jung-Bin; Yang, D. G.; Kim, Y. G.; Hahn, Seungyong; Lee, Haigun

doi:10.1063/1.4963680

Cited by 10 publications

(4 citation statements)

References 33 publications

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“…Now that J y is known, E x can be computed using equation (8). The continuum model is not limited to the specific numerical method described above.…”

Section: Numerical Solution Of the Continuum Modelmentioning

confidence: 99%

“…Since then, no-insulation ReBCO coils have been successfully applied in a number of high-field magnets [2][3][4]. Noinsulation coils are also considered for application in rotating machines [5][6][7][8][9][10][11][12][13][14] and in linear actuators [15][16][17]. However, in such devices the coils are subjected to time-dependent magnetic fields and may well suffer from additional coupling loss due to induced currents that flow through the turn-to-turn contacts, as recently illustrated by Wang et al in no-insulation round pancake-type coils [18].…”

Section: Introductionmentioning

confidence: 99%

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Calculation and measurement of coupling loss in a no-insulation ReBCO racetrack coil exposed to AC magnetic field

Otten

Harmsel

Dhalle

et al. 2023

Supercond. Sci. Technol.

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No-insulation coils are in general self-protecting and can therefore generally be operated at higher current densities. However, the electrical turn-to-turn connections may cause additional AC loss when charging the coil or when it is exposed to a time-dependent magnetic field. In this work, we study the case of a no-insulation ReBCO tape racetrack coil exposed to a uniform AC field applied parallel to the tape surface. We show that an anisotropic continuum model allows to formulate efficient analytical approximations for coupling loss in the low- and high-frequency limits. For intermediate frequencies, the continuum model needs to be evaluated numerically. The model was validated with representative measurements of AC loss in the coils, measured calorimetrically as well as magnetically using pick-up coils. The validation experiment nicely confirms the predicted frequency dependence of the coupling loss, which is P ∝ f 2 at low frequencies and P ∝ √f at high frequencies, due to the skin effect. The transition between low- and high-frequency regimes occurs around a characteristic frequency f c that is directly related to the characteristic time constant τ = 1/2πf c associated with the current decay in straightforward (dis)charge experiments.

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“…Now that J y is known, E x can be computed using equation (8). The continuum model is not limited to the specific numerical method described above.…”

Section: Numerical Solution Of the Continuum Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calculation and measurement of coupling loss in a no-insulation ReBCO racetrack coil exposed to AC magnetic field

Otten

Harmsel

Dhalle

et al. 2023

Supercond. Sci. Technol.

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show abstract

“…Therefore, in order to apply superconducting coils wound with HTS wiring to electrical machines, it is very important to protect the HTS coils from the quenching phenomenon. The approach known as the no-insulation (NI) winding technique is a viable quench-protection method for HTS coils [16][17][18][19][20][21][22][23][24][25]. The NI winding technique involves the fabrication of coils without insulation materials between the turns.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the current flows through the stabilizer layer constituting the superconducting wire, and it is thus bypassed. As a result, NI coils can be protected from quenching without complicated quench detection schemes and/or protection devices, simplifying these HTS coil systems [16][17][18][19][20][21][22][23][24][25]. However, the NI HTS coil is associated with an intrinsic charging/discharging delay phenomenon.…”

Section: Introductionmentioning

confidence: 99%

A Flux-Controllable NI HTS Flux-Switching Machine for Electric Vehicle Applications

2020

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This paper deals with a flux-controllable NI HTS flux-switching machine (FSM) for electric vehicle (EV) applications. In a variable-speed rotating machine for EVs, such as electric buses, electric aircraft and electric ships, an electric motor capable of regulating the flux offers the advantage of constant output operation. In general, conventional HTS rotating machines have excellent flux-regulation performance, because they excite an HTS field coil. However, it is difficult to ensure any flux-regulation capabilities in HTS rotating machines using HTS field coils that apply the no-insulation (NI) winding technique, due to the inherent charge and discharge delays in these machines. Nevertheless, the NI winding technique is being actively researched as a key technology for the successful development of HTS rotating machines, because it can dramatically improve the operational stability of HTS field coils. Therefore, research to implement an HTS rotating machine with flux-regulation capabilities, while improving the operating stability of the HTS field coil using the NI winding technique, is required for EV applications. In this paper, we propose an HTS rotating machine with a flux switching structure, a type of topology of a rotating machine that is being actively studied for application to the electric motors used in EVs. The proposed HTS flux-switching machine (FSM) uses NI field coils, but additional field windings are applied for flux regulation, which enables flux control. In this study, an NI HTS field coil was also fabricated and tested because the characteristic resistance value should be used for the design and characteristic analyses of machines which utilize an NI coil. The simulation model used to analyze the flux-regulation performance capabilities of the NI HTS FSM were devised based on the characteristic resistance values obtained from a charging test of the fabricated NI HTS field coil. This study can provide a good reference for further research, including work on the manufacturing of a prototype NI HTS FSM for EV applications, and it can be used as a reference for the development of other HTS rotating machines, such as those used in large-scale wind power generation, where flux-regulation capabilities are required.

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Enhancement of high-temperature superconducting coil stability using doped smart insulation materials for superconducting magnet applications

Mussa,

Noh,

Kwon

et al. 2024

Chinese Journal of Physics

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A novel no-insulation winding technique of high temperature-superconducting racetrack coil for rotating applications: A progress report in Korea university

Cited by 10 publications

References 33 publications

Calculation and measurement of coupling loss in a no-insulation ReBCO racetrack coil exposed to AC magnetic field

Calculation and measurement of coupling loss in a no-insulation ReBCO racetrack coil exposed to AC magnetic field

A Flux-Controllable NI HTS Flux-Switching Machine for Electric Vehicle Applications

Enhancement of high-temperature superconducting coil stability using doped smart insulation materials for superconducting magnet applications

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