On the future sustainable ultra-high-speed maglev: An energy-economical superconducting linear thrusting system

Dong, Fangliang; Hao, Luning; Park, Dong Keun; Iwasa, Y.; Huang, Zhen

doi:10.1016/j.enconman.2023.117247

Cited by 8 publications

(2 citation statements)

References 34 publications

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“…The significance of this applied field is as follows. In recent years, rotating and linear synchronous machines employing NI PCM coils have attracted increasing attention [4,14,33,[85][86][87][88]. In these applications, although the HTS rotor magnets are normally synchronous with the stator field and resemble a static field, they occasionally operate in dynamic conditions and encounter considerable non-synchronous time-varying fields, such as during the acceleration/deceleration and starting/breaking processes (which are frequent for wind turbines), electrical and mechanical vibrations, primary-coil-currentcontrol and out-of-step faults, and active short-circuits of the machine [89][90][91].…”

Section: Current Distribution Overviewsmentioning

confidence: 99%

Study of the demagnetization behavior of no-insulation persistent-current mode HTS coils under external AC fields by 3D FEM simulation

Zhong,

Wu,

et al. 2024

Supercond. Sci. Technol.

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The no-insulation (NI) winding technique is promising to be applied in the persistent-current mode (PCM) operation of high-temperature superconducting (HTS) coils to provide those advantages. To apply the NI PCM coil, its demagnetization behaviour (i.e., decay of persistent DC current) by external AC field, which occurs in maglev trains, electric machines, and other dynamic magnet systems, is essential to be understood. For this purpose, a 3D FEM model, capturing the full electromagnetic properties of NI HTS coils, is established. This work has studied three kinds of AC fields, observing the impact of turn-to-turn contact resistivity on demagnetization rates, which is attributed to current distribution modulations. Under transverse AC field, the lower contact resistivity attracts more transport current to flow in the radial pathway to bypass the ‘dynamic resistance’ generated in the superconductor, leading to slower demagnetization. Under axial AC field, the demagnetization rate exhibits a non-monotonic relation with the contact resistivity: (1) the initial decrease of contact resistivity leads to concentration of induced AC current on the outer turns, which accelerates the demagnetization; (2) the further decrease of contact resistivity makes the current smartly redistribute to avoid to flow through the loss-concentrated outer turns, thus slowing down the demagnetization. Under the rotating DC field, a hybrid of the transverse and axial fields, the impact of contact resistivity on the demagnetization rate exhibits combined characteristics of the transverse and axial components. Besides, quantitative prediction on the demagnetization rate of NI PCM coil under external AC field is instructive for practical designs and operations, which is tried by this 3D FEM model, and a comparison with experimental result is conducted.

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Section: Current Distribution Overviewsmentioning

confidence: 99%

Study of the demagnetization behavior of no-insulation persistent-current mode HTS coils under external AC fields by 3D FEM simulation

Zhong,

Wu,

et al. 2024

Supercond. Sci. Technol.

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“…Operating in semi-persistent mode, superconducting magnets in high-temperature superconducting (HTS) electro-dynamic suspension magnetically levitated trains can achieve multiple benefits. Semi-persistent mode eliminates the huge heat leakage on the current leads [1], reduces the burden on the cooling system, and simplifies the magnet system under dynamic operating conditions [2]. However, semi-persistent mode requires power supply during the excitation.…”

Section: Introductionmentioning

confidence: 99%

A novel heater-triggered HTS semi-persistent current switch with high switching-off resistance

Tan,

Huang

2023

Supercond. Sci. Technol.

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A semi-persistent current switch (semi-PCS) with a simple fabrication process, high switching-off resistance, and minimal power dissipation during operation is required to realize the semi-persistent mode in a high-temperature superconducting (HTS) magnet. In this study, a semi-PCS with high switching-off resistance was developed by optimizing the HTS tape structure in a heater-triggered semi-PCS. This optimization was achieved by selectively removing a portion of the conductive and superconducting layers on the surface and edges of the HTS tapes. The microstructure of the treated HTS tape was then analyzed. The resistance of the semi-PCS in a non-superconducting state was measured, and it was connected to an insulated coil for performance testing. To further evaluate its impact, an equivalent electrical circuit model was developed and used to predict the effect of the semi-PCS when applied to a larger superconducting coil. Furthermore, the study explored the impact of the excitation rates on the power dissipation and heat generation of the semi-PCS.

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On the future sustainable ultra-high-speed maglev: A superconductor magnet technology enabling high energy efficiency and robustness

Dong,

Park,

Huang

et al. 2024

Energy Conversion and Management

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On the future sustainable ultra-high-speed maglev: An energy-economical superconducting linear thrusting system

Cited by 8 publications

References 34 publications

Study of the demagnetization behavior of no-insulation persistent-current mode HTS coils under external AC fields by 3D FEM simulation

Study of the demagnetization behavior of no-insulation persistent-current mode HTS coils under external AC fields by 3D FEM simulation

A novel heater-triggered HTS semi-persistent current switch with high switching-off resistance

On the future sustainable ultra-high-speed maglev: A superconductor magnet technology enabling high energy efficiency and robustness

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