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284 results on '"Zhu, Xinkai"'

16. AC Loss Calculation of Racetrack-Shaped HTS-Excitation Magnet for Electrical Machine Considering End Part

Author

Sang, Mingzhe, Li, Xianglin, Wang, Shaorui, Zhu, Xinkai, Wang, Yubin, and Hua, Wei

Abstract

Racetrack-shaped high-temperature-superconducting (HTS) coated-conductor (CC) magnets are potentially used in HTS electrical machines. In order to accurately calculate the AC loss of this kind of HTS magnets to facilitate the machine design for estimating the cooling power and cost, a three-dimensional (3-D) numerical modeling method based on the T-A formula is proposed in this paper. The key is to establish different coordinate systems for different parts of the racetrack-shaped magnet, thus comprehensively analyzing the AC loss characteristics of the whole magnet. By comparing with the widely used 2-D T-A formula model, the validity of the proposed method is verified.

Published
2024
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17. Characteristics of the Warming Trend During Winter Wheat Growing Seasons in Jiangsu Province of China

Author

Xu, Xiangying, Zhu, Xinkai, Guo, Wenshan, Li, Chunyan, Ding, Jinfeng, Rannenberg, Kai, Editor-in-Chief, Sakarovitch, Jacques, Series Editor, Goedicke, Michael, Series Editor, Tatnall, Arthur, Series Editor, Neuhold, Erich J., Series Editor, Pras, Aiko, Series Editor, Tröltzsch, Fredi, Series Editor, Pries-Heje, Jan, Series Editor, Whitehouse, Diane, Series Editor, Reis, Ricardo, Series Editor, Furnell, Steven, Series Editor, Furbach, Ulrich, Series Editor, Winckler, Marco, Series Editor, Rauterberg, Matthias, Series Editor, Li, Daoliang, editor, and Zhao, Chunjiang, editor

Published
2019
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23. Electromagnetic induction with time-varying magductance under constant magnetic field.

Author

Qin, Wei, Cheng, Ming, Zhu, Xinkai, Wang, Zheng, and Hua, Wei

Subjects
ELECTROMAGNETIC induction, FARADAY'S law, MAGNETIC fields, SUPERCONDUCTING coils, MECHANICAL energy
Abstract

Electrical energy is becoming more popular due to the fact that it is economic, practical, clean, and easy to control and convert energy compared to other forms of energy. Currently, however, most of the electrical energy is converted from or to mechanical energy based on the well-known Faraday's law of electromagnetic induction, which states that a current will be induced in a closed conductive coil exposed to a changing magnetic field. For that purpose, either the magnetic field itself must be changing or the magnetic field must be moving relative to the closed conductive coil. While investigating the physical significance of magductance (or magnetic-inductance), we unearthed a new electromagnetic induction mechanism that the electrical current is induced in a closed conductive coil with the invariant magnetic field by changing the magnetic parameter of magductance of the closed coil. Time-varying magductance is achieved by changing the conductivity of the coil. To demonstrate the feasibility of the electromagnetic induction, both theoretical validation and experimental verification are undertaken. We built a closed superconducting coil and successfully measured the induced electrical currents in the cooling process of the closed superconducting coil under an invariant magnetic field, thus verifying the new law of electromagnetic induction. [ABSTRACT FROM AUTHOR]

Published
2024
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29. Magnetic Shielding Design and Performance Improvement of HTS Coil for Single HTS-Excitation Claw-Pole Field-Modulation Machine

Author

Li, Xianglin, Sang, Mingzhe, Wei, Zhen, Zhang, Zhiheng, Zhu, Xinkai, Wang, Yubin, and Hua, Wei

Abstract

In the single high-temperature-superconducting (HTS)-excitation claw-pole field-modulation (SHTS-CPFM) machine investigated in this article, the armature reaction field that penetrates the HTS-excitation coil has a nonnegligible amplitude, which would lead to the reduction of critical current Ic, thus decreasing the electromagnetic performance of the SHTS-CPFM machine. Therefore, the purpose of this article is to propose and design a compound magnetic shielding, which consists of segmented flux diverter (FD) and superconducting shielding layer. The innovation is the proposal of segmented FD having a smaller size and stronger flux diversion ability compared with the unsegmented FD, and introducing the YBCO-tape shielding layer instead of traditional metal shielding layer to achieve improved ac flux shielding due to the full use of the Meissner effect. The results show that by introducing the proposed CMS, the critical current Ic and the field current If of the HTS-excitation coil in the analyzed SHTS-CPFM machine can be increased by 14.8% and 12%, respectively, thus achieving a 6.4% improvement in machine torque capacity.

Published
2024
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50. Performance Analysis of Distributed HTS Armature Winding Direct Drive Wind Generator With Active Magnetic Shielding Layer

Author

Zhu, Xinkai, Qi, Guangyu, Han, Peng, Wang, Yubin, Hua, Wei, Cheng, Ming, and Cui, Yingmin

Abstract

High-temperature superconducting (HTS) electrical machine has higher torque density and higher efficiency than permanent magnet electrical machine, showing a great application prospect in the field of offshore wind power generation. However, if there is applied magnetic field acting on the wide plane of HTS tape perpendicularly, the current-carrying capacity of the HTS tape will be greatly reduced, resulting in the performance limitation of the HTS electrical machine. In order to reduce the negative effect of the applied magnetic field on the HTS tape, this paper proposes a new distributed HTS armature winding direct drive wind generator (DHTSAW-DDG) with active magnetic shielding layer. In this paper, the topology and working principle of the DHTSAW-DDG is clearly illustrated, meanwhile, the basic electromagnetic performances of the DHTSAW-DDG are carefully analyzed and compared with the counterpart with the copper armature winding. The results show that the active magnetic shielding layer made of HTS material can significantly weaken the negative effect of the applied magnetic field on the current-carrying capacity of the HTS tape. The electromagnetic performance of the HTS electrical machine can be significantly improved, if the distributed HTS armature winding and the active magnetic shielding layer are adopted. The torque density and the power factor of the proposed DHTSAW-DDG with active magnetic shielding layer can increase approximately 40% than the copper armature winding electrical machine with same topology.

Published
2023
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