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International Conference of Electrical, Electronic and Networked Energy Systems, EENES 2024

作者： Xie, Yunlong Yuan, Zhao Chen, Lixue State Key Laboratory of Advanced Electromagnetic Technology Huazhong University of Science and Technology Wuhan430074 China Key Laboratory of Pulsed Power Technology Ministry of Education School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China

ISBN: (纸本)9789819620456

Mechanical DC circuit breakers have become an irreplaceable part of flexible DC power grids because of their advantages of high economy, low con-duction impedance, and reliable control. However, the large volume of the charging circuit and the high interruption pressure in low current are still the problems it faces. To address the aforementioned issues, a Coupled Self-charging Mechanical DC Circuit Breaker (CSC-DCCB) is proposed. This innovative solution mitigates the risk of switch arc reignition during the commutation process by incorporating a self-charging circuit. The energy consumption process of metal-oxide varistor will cause the capacitor to complete recharging, and this voltage will be used for the reclosing of the CSC-DCCB. Secondly, the parameter of the CSC-DCCB is optimized to achieve a lower overall capacity of the circuit breaker and the rated voltage of the converter switches, which retains the traditional low conduction loss. Finally, the feasibility of CSC-DCCB is validated through PSCAD, the technical parameters of CSC-DCCB are compared with traditional DCCB, showing that CSC-DCCB has better economic efficiency. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Flexible electronics

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Electrostatic Interference Suppression Method for Magnetic Flux Measurement in the Formation Area of HFRC Device 11th

Electrostatic Interference Suppression Method for Magnetic F...

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11th Frontier Academic Forum of Electrical engineering, FAFEE 2024

作者： Zhang, Yujun Chen, Zhipeng Rao, Bo Yang, Yong Li, Zhuolong Zhao, Yanhao Wang, Liye State Key Laboratory of Advanced Electromagnetic Technology International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China

ISBN: (纸本)9789819788231

This paper proposes a comprehensive solution to address the interference challenges encountered during magnetic flux loop measurement of flux in Field-Reversed Configuration fusion devices. The high-frequency magnetic field generated by the high voltage discharge coil induces a high voltage in the magnetic flux loop circuit. However, the accompanying electrostatic interference significantly affects the measurement accuracy of magnetic flux. Although traditional isolation, shielding, and grounding techniques can mitigate electrostatic interference to some extent, their implementation is challenging, and they have stringent requirements for the grounding system. In view of this, this study added an electrostatic shielding layer between the magnetic flux loop and the discharge coil. Experimental results show that this measure effectively suppresses electrostatic interference. Simultaneously, this study utilizes a differential measurement method to further reduce electrostatic interference. Experiments show that the flux loop can accurately reflect the flux value, and the correlation coefficient between the measured flux and the theoretical value is 0.935. These improvements not only significantly enhance the accuracy and reliability of magnetic flux measurements but also provide more precise data support for magnetic diagostics research and experiments in Field-Reversed Configuration fusion devices. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Magnetic shielding

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The analysis and assessment of DC-Link voltage control loop dynamics on the transient synchronization stability of grid-following converters

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Electric Power Systems Research 2025年 247卷

作者： Xie, Chenyang Lin, Xinchun Sun, Huiqiang Wei, Juntian Zhang, Jiayan State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

The transient synchronization stability of grid-following voltage source converters has been extensively investigated, but most of the previous literature has only studied the transient dynamics of the phase-locked loop (PLL) while ignoring the dynamics of the DC-link voltage control (DVC) loop. When the bandwidths of the PLL and DVC are relatively close to each other, erroneous conclusions will be derived if neglecting the transient influence of the DVC loop. This paper first takes into account the transient dynamics of the DVC loop while applying the improved equal-area criterion (EAC) analysis, which reveals how the DVC loop affects the transient synchronization stability. Then, a fourth-order model considering the DVC dynamics is obtained to quantitatively determine a reasonable range of bandwidth and damping ratio for the DVC loop. Moreover, the extent of the influence of DVC on transient synchronization stability with variation of grid strength is analyzed. © 2025

关键词： Transient analysis

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Numerical Study of the Current Density on the Armature and Rail Interface with Dynamic Contact

Numerical Study of the Current Density on the Armature and R...

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International Conference of Electrical, Electronic and Networked Energy Systems, EENES 2024

作者： Xu, Jinghan Xia, Shengguo Chen, Lixue Ministry of Education Hubei Wuhan430074 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Hubei Wuhan430074 China School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China

ISBN: (纸本)9789819620791

The electrical contact between the armature and rail is acknowledged as imperfect electrical contact (ImPEC), exhibiting characteristics distinct from bulk behavior. It is important to understand the current distribution of the ImPEC for future design and optimization. This paper proposes ImPEC boundary conditions by combining the contact layer model (CLM) and the Cooper-Mikic-Yoranovich model (CMYM), and the current distribution is numerically studied. Variations in the contact pressure and current density with time are analyzed. The results show a rapid increase in the contact pressure and area during the current ramp-up stage, being constant in the flat stage, and a gradual decline in the current ramp-down stage. The current path changes with the contact area, and the current shifts from the trailing edge to the leading edge over time. Additionally, comparative calculations are performed to analyze current variations under dynamic contact. Results suggest that the current distribution is influenced by magnetic diffusion and forced shifts of current caused by dynamic contact. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Threshold current density

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In-situ growth of cross-link NiAl-LDH nanosheets on the inner/outer surfaces of carbon microtubes for anti-corrosive electromagnetic wave absorption

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Journal of Materials Science and technology 2025年 238卷 109-118页

作者： Liu, Rui Liu, Xiao Wu, Lihong Du, Changlong Lv, Haiming Wan, Gengping Xiong, Hualin Yuan, Xiang Wang, Jieping Wang, Guizhen Institute of Electromagnetic Protection Materials and Spectral Innovation Technology State Key Laboratory of Tropic Ocean Engineering Materials and Materials Evaluation School of Materials Science and Engineering Hainan University Haikou570228 China Center for New Pharmaceutical Development and Testing of Haikou Center for Advanced Studies in Precision Instruments Haikou570228 China Key Laboratory of Pico Electron Microscopy of Hainan Province Center for Advanced Studies in Precision Instruments Haikou570228 China

electromagnetic wave (EMW) absorbers with anti-corrosion property are highly desired to enhance the durability of military targets in harsh condition. Herein, cross-link NiAl-layered double hydroxide (NiAl-LDH) nanosheets on the inner/outer surfaces of carbon microtubes (CMTs) are ingeniously constructed through the combination of atomic layer deposition technique and a hydrothermal method. The obtained NiAl-LDH/CMT composite exhibits excellent EMW absorption and corrosion resistance performance. The large internal cavity of CMT significantly enhances impedance matching. The uniform distribution of NiAl-LDH nanosheets on both the inner and outer surfaces of CMT generates numerous heterogeneous interfaces that induce substantial polarization loss. Consequently, at a filler rate of only 5 wt.%, the NiAl-LDH/CMT composite exhibits a minimum reflection loss of −60.2 dB and a maximum effective absorption bandwidth of 5.9 GHz. In addition, the combined high impermeability of CMT and the effective Cl−-trapping ability of NiAl-LDH endows NiAl-LDH/CMT composite with outstanding corrosion protection property in simulated seawater environment. Furthermore, the PO43− anions are effectively incorporated into the NiAl-LDH interlayer via anion exchange, which can further enhance corrosion protection capacity through surface inactivation from slow-release PO43− anions without reducing their EMW absorption performance. In summary, this work can give guidance for the development of efficient anti-corrosion EMW absorption materials. © 2025

关键词： Anodic protection

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Start-to-end simulation for a compact terahertz free electron laser with a beam chopper system

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Nuclear Science and Techniques 2025年第7期36卷 1-11页

作者： Luo, Rui-Ying Chen, Qu-Shan State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China

A thermionic gun is endowed with a long bunch tail, which presents challenges for the compact terahertz free electron laser (FEL) facility at the Huazhong University of Science and technology. Owing to a large energy spread, the tail particles do not contribute to the radiation. In the original design, an x-direction slit is used in the dispersive section of the transport line to remove the tail particles. This paper presents an improved scheme to remove the tail by introducing an RF beam chopper system at the exit of the electron gun, to prevent a significant number of tail particles from entering the linac. The facility remains compact while effectively removing the tail of the bunch. The parameters of the beam chopper system are designed. Bunch parameters and radiation performance are analyzed via a start-to-end simulation. The findings indicate that 43% of the particles can pass through the beam chopper system for subsequent acceleration and transport, which saves the RF power, reduces beam loss in the linac, reduces background noise, and suppresses the sideband instability. Simultaneously, the beam chopper system causes an increase in beam emittance, energy spread, and an offset in the center of the bunch. These effects can be mitigated by a solenoid, linac, and steering coils. The simulation results for the FEL show that the micro-pulse energy is greater than 1.1 μJ in the frequency range of 2.8–9.7 THz, and the maximum micro-pulse energy is 1.28 μJ. © The Author(s), under exclusive licence to China Science Publishing & Media Ltd. (Science Press), Shanghai Institute of Applied Physics, the Chinese Academy of Sciences, Chinese Nuclear Society 2025.

关键词： Particle beam bunching

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Low-temperature active soldering of 5A06-Al alloy and Ti-Cu-Ni alloy mesh-reinforced SAC305 composite solder: Interfacial bonding behavior and joint properties

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Journal of Materials Science and technology 2025年 235卷 313-323页

作者： Li, Dan Xi, Bangfu Xiao, Yong Song, Lizhi Zhang, Jian Luo, Dan Goodall, Russell School of Materials Science and Engineering Wuhan University of Technology Wuhan430070 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Department of Materials Science and Engineering The University of Sheffield SheffieldS1 3JD United Kingdom

Achieving reliable bonding is critical for low-temperature active soldering in Al alloys. In this study, a novel Ti-Cu-Ni alloy mesh-reinforced SAC305 composite solder was developed for active soldering of 5A06-Al alloy at 350 °C. Effects of soldering time on the microstructure and mechanical properties of joints were investigated, and the interfacial bonding mechanism of joints was analyzed. Results showed that the (Cu, Ni)6Sn5 phase was formed between alloy mesh and SAC305 solder in the active composite solder, while Ti atoms were uniformly released from the alloy mesh. Metallurgical products within joints mainly comprised (Cu, Ni)6Sn5 and Al3(Ni, Cu)2 phases, which developed with increasing soldering time. An amorphous Al2O3 layer and a Mg-containing layer were formed at the Al substrate/SAC305 solder interface. Mg atoms could enhance the charge transfer between Ti atoms and oxide film, attracting the diffusion of Ti atoms to oxide film. The oxide film removal processes relied on the synergistic impacts of Ti and Mg. The highest shear strength of joints reached 53.21 ± 0.91 MPa, exceeding previously reported properties for low-temperature active soldering by over 100 %. This exploration may provide insights into developing low-temperature active soldering technologies for Al alloys. © 2025

关键词： Titanium alloys

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Regional Short-Term Wind Power Prediction Based on CEEMDAN-FTC Feature Mapping and EC-TCN-BiLSTM Deep Learning

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Wind Energy 2025年第6期28卷

作者： Qin, Guoyuan Peng, Xiaosheng Yang, Zimin State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

Regional-scale holistic wind power prediction (WPP) is pivotal to securing the safety, stability, and economic efficiency of power systems. To improve the accuracy of regional short-term WPP, a method based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), fine-to-coarse (FTC) feature mapping, and error compensation-temporal convolutional network-bidirectional Long short-term memory network (EC-TCN-BiLSTM) is proposed in this paper. First, the regional input features, encompassing data from numerous wind farms, are decomposed using the CEEMDAN algorithm to extract intrinsic mode functions (IMFs) and residuals at different time scales. Second, the decomposed IMFs and residuals are reconstructed using the adaptive FTC feature mapping technique, forming a high-dimensional feature set in the time-frequency domain, which boasts fewer features than the original set, thus diminishing the computational intricacy of the prediction model. Third, by combining the strengths of TCN and BiLSTM neural networks, the temporal and spatial correlations of input features can be captured effectively. Fourth, the integration of the EC module corrects the systematic errors of the prediction results, thereby further improving the prediction accuracy. Finally, case studies elucidate the efficacy of the proposed WPP method, illustrating a 0.41%–2.4% diminution in 24-h-ahead root mean square error (RMSE) and a 0.68%–2.63% reduction in 96-h-ahead RMSE relative to conventional methodologies. © 2025 The Author(s). Wind Energy published by John Wiley & Sons Ltd.

关键词： Convolutional neural networks

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A Novel High Torque Density Spoke-Array Permanent Magnets Vernier Machine with Magnets Bridge

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IEEE Transactions on Industry Applications 2025年

作者： Zhang, Yuwei Zhao, Yu Li, Dawei Qu, Ronghai Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Wuhan430074 China

In recent years, permanent magnet vernier machine (PMVM) has drawn more attention due to their high torque density. To further improve torque capability, Spoke-array (SA) PM having better flux focusing effect are applied. However, SAPMVM suffers from a considerable torque reduction due to the deteriorated low order working flux harmonics caused by flux barrier effect. Especially, the higher pole ratio (PR), i.e., the ratio of PM pole-pair to armature pole-pair, the severer torque drop of SAPMVM. In this paper, a novel SAPMVM is proposed, where the magnets bridge is introduced, which can effectively restrict the flux barrier effect. As a result, both the working flux harmonics and torque density of SAPMVM are enhanced. To analyze the operating principle of proposed SAPMVM with magnets bridge, an equivalent magnet circuit model is established. Moreover, the electromagnetic performances of the proposed SAPMVM are compared with regular SAPMVM by FEA, where the torque of proposed SAPMVM has increased by 43.3% and 175.6% under rated-load when the PR is selected as 5 and 11. © 1972-2012 IEEE.

关键词： Permanent magnets

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Dielectric Mechanism and Spectrum Prediction Model for Insulating Paper Based on Three-Dimensional Frequency-Domain Spectroscopy

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IEEE Transactions on Dielectrics and Electrical Insulation 2025年

作者： Liu, Ruiqi Wang, Shengkang Lin, Fuchang Li, Hua Ministry of Education State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Wuhan430074 China

Moisture is a serious concern for transformers, as it will degrade insulation properties and accelerate aging. The dielectric mechanisms of oil-immersed paper (OIP) and the influence of moisture still remains contentious in existing studies, which prevents the application of Frequency-Domain Spectroscopy (FDS) technology in moisture assessment of transformers. OIP is a biphasic composite material composed of oil and paper, and the existence of oil would complicate the understanding of the dielectric mechanisms in solid insulation. Therefore, this study focuses on investigating the dielectric properties of non-immersed insulating paper using FDS. Firstly, the spectra of paper with different moisture content were analyzed, and the relationship between dielectric parameters and moisture was quantified through the proposed dielectric model of insulating paper. Then, a three-dimensional dielectric model for spectrum prediction was established, and the feasibility and universality of model was verified. Results show three distinct dielectric response processes in insulating papers: the hopping conduction (RI), the low-frequency relaxation polarization (RII), and the high-frequency relaxation polarization (RIII). With increasing moisture content, RI and RII processes shift synchronously and exponentially towards higher frequencies with the dielectric curve shape maintained, while RIII process is unaffected. Moreover, the proposed spectrum prediction model can accurately predict the spectrum of insulating paper with varying moisture content. The dielectric response mechanism and three-dimensional dielectric model of insulating paper identified in this study provide the theoretical basis and data support for subsequent studies of the dielectric mechanism and moisture assessment of oil-immersed paper. © 1994-2012 IEEE.

关键词： Frequency domain analysis

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