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SSRN 2023年

作者： Cui, Yingjie Dong, Chiheng Fu, Caida Xu, Zhongtang Tang, Minghui Wang, Chengduo Ma, Yanwei Key Laboratory of Applied Superconductivity Institute of Electrical Engineering Chinese Academy of Sciences Beijing100190 China Institute of Electrical Engineering and Advanced Electromagnetic Drive Technology Qilu Zhongke Jinan250013 China University of Chinese Academy of Science Beijing100049 China School of Material Science and Engineering Zhengzhou University Zhengzhou450001 China

Boundaries and interfaces of heterostructures play a critical role in mediating the magnetic and electronic properties of superconductors. Here, we applied a simple annealing method to vary the low-temperature crystal structure of BaFe2-xNixAs2 single crystals. The annealing process raises the temperature of the structural phase transition but induces minor modifications to the magnetic and superconducting orders. The orthorhombic distortion induces twin domain boundaries which enhance the electron scattering. In the meantime, the improved density of structural domain boundaries renders them to intersect and form a fine maze-like structure. Together with the innate point pinning centers in BaFe2-xNixAs2, they constitute a novel pinning landscape that largely enhances the critical current density. Our studies provide a new framework to strengthen vortex pinning and push forward high-field applications of iron-based superconductors. © 2023, The Authors. All rights reserved.

关键词： Iron-based Superconductors

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Direct Laser Printing of 3d Optical Imaging Based on Full-Spectrum Solar-Absorption-Enhanced Perovskite-Type Oxides

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SSRN 2023年

作者： Luo, Xiaobo Hu, Songhan Duan, Qiudong Zhou, Dacheng Wang, Qi Yang, Yong Chen, Jialin Wen, Yugeng Qiu, Jianbei Faculty of Material Science and Engineering Kunming University of Science and Technology Kunming650093 China Key Lab. of Advanced Materials of Yunnan Province Kunming650093 China Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern University Shenyang110819 China School of Materials Science and Engineering Northeastern University Shenyang110819 China Key Laboratory of Advanced Technologyies for Comprehensive Utihzatron of Platinum Metal China

The exploration of the solar light absorption by a material is of great use in photonics and optoelectronics. However, the fully exploiting of the solar spectrum of well-known wide-bandgap perovskite oxides (2.7–5 eV), remains very challenging. We show that the selective occupation of Bi3+ in the octahedrally coordinated Ba2+ is responsible for creating sub-bandgap states (as low as 0.6 eV), nearly 9 times lower than pristine bandgap (5.2 eV). We reveal that the role of the 6s6p excited state of Bi3+ is as a bridge to promote the dipole-allowed band-band transition for strong absorption. Furthermore, we demonstrate the double-sided laser printing of three-dimensional optical imaging based on the photothermal effect, enabling write-once-read-many information storage with ultrahigh stability and good data retention. Our results make Ba3–xGa2O6:xBi3+ a promising candidate for photovoltaics, ferroelectrics, photocatalysis, broadband photodetectors as well as other photonic and optoelectronic applications. © 2023, The Authors. All rights reserved.

关键词： Light absorption

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Optimization of SMES-Battery Hybrid Energy Storage System for Wind Power Smoothing

Optimization of SMES-Battery Hybrid Energy Storage System fo...

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2020 IEEE International Conference on Applied Superconductivity and electromagnetic Devices, ASEMD 2020

作者： Chen, Lei Zhang, Xuyang Han, Pu Chen, Hongkun Xu, Ying Ren, Li Tang, Yuejin School of Electrical Engineering and Automation Wuhan University Wuhan China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781728152158

In this paper, a hybrid energy storage system (HESS) containing superconducting magnetic energy storage (SMES) and battery is adopted to smooth wind power fluctuations, and the optimal capacity of the HESS is investigated. Using a proper lowpass filter, low-frequency and high-frequency components of wind power fluctuations are decomposed, and the primary power-sharing strategy is designed for the SMES and the battery. Considering investment cost and maintenance cost, the objective function of minimizing the annual cost of the SMES-battery HESS is created, and the simulate anneal algorithm is used to acquire the optimal solution. Aiming at a 500kW wind power system with a SMES-battery HESS, the optimization calculation is implemented. The results well demonstrate the effectiveness and adaptability of the proposed optimization approach. © 2020 IEEE.

关键词： Wind power

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Effect of oxygen doping sources on enhancing air stability and lithium metal compatibility of Li 5.5 PS 4.5 Cl 1.5 electrolyte

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Chinese Chemical Letters 2025年

作者： Linfeng Peng Cong Liao Jiayue Peng Shuai Chen Tianyu Lei Shijie Cheng Jia Xie State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074 China

Oxygen (O) doping is a promising strategy for enhancing the air stability and lithium metal compatibility of sulfide solid electrolytes (SSEs). However, the impact of various O sources on the structure and properties of SSEs remains unclear. In this study, we synthesized a series of O-doped electrolytes, Li5.5PS4.5-xOxCl1.5 (LPSCOx, 0.1 ≤ x ≤ 0.5), using Li2O and P2O5 as O sources, and systematically investigated their differences in structure, air stability, and electrochemical properties. O preferentially substitutes sulfur (S) at the 16e site and begins to replace S at the 4d site once a certain O concentration is reached. Notably, the P2O5-doped electrolytes (P-LPSCOx) exhibit a greater oxygen tolerance content (0.24) at the 16e site, along with better air stability, higher ionic conductivity, and superior lithium metal compatibility. XRD, SEM, and XPS analyses reveal that the P2O5-doped electrolytes exhibit larger cell parameters, higher densification, and fewer side reactions with lithium metal compared to the Li2O-doped counterparts. This study provides valuable insights into the development of high-performance O-doped sulfide electrolytes.

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Transient Stability Analysis of the Standalone System Constructed by Paralleled Grid-Forming Converters under Symmetrical Short-Circuit Fault

Transient Stability Analysis of the Standalone System Constr...

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Smart Power & Internet Energy Systems (SPIES), International Conference on

作者： Jiayan Zhang Xinchun Lin Guangzhou Huang Huiqiang Sun Dan Liu Kezheng Jiang Huazhong University of Science and Technology Wuhan China State Key Laboratory of Advanced Electromagnetic Engineering and Technology State Grid Hubei Electric Power Co. LTD Electric Power Research Institute Wuhan China

With the rapid development of renewable energy, the micro grid and standalone system are greatly penetrated by grid-forming converters which establish the voltage and frequency of the system. The grid-forming converter like the synchronous generator may threaten the standalone system safe and stable operation under large disturbances. Based on that, this paper investigates the transient stability of the standalone system constructed by two paralleled grid-forming converters suffering from symmetrical short-circuit fault. Firstly, the transient model of the standalone system is established. Secondly, based on state-space equations, the transient stable boundary is derived to analyze the impact of circuit parameters and control parameters on the transient stability of the system, which guides the parameter optimization. Furthermore, the optimal selection method of control parameters of grid-forming converters is proposed to improve the transient stability. At last, the effectiveness of analytical results is verified by simulations.

关键词： Power system stability Stability analysis Mathematical models Synchronous generators Circuit stability Circuit faults Transient analysis

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Study on a 48-Slot Interior Permanent Magnet Synchronous Motor in the Aircraft Drive System

Study on a 48-Slot Interior Permanent Magnet Synchronous Mot...

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Power and Electrical technology Conference (APET), Asia

作者： Yuhang Xie Fei Xiong Rui Yan Yu Xiang Kai Yang Weican Yan School of Reliability and Systems Engineering Beijing University of Aeronautics and Astronautics Beijing China State Key Laboratory of Advanced Electromagnetic Technology Huazhong University of Science and Technology Wuhan China Marketing Department SG Micro Corp Beijing China Wolong Electric Group Co. LTD Shangyu China

The torque performance of the interior permanent magnet synchronous motor (IPMSM) has been widely concerned and studied for many years. This article focuses on the structure design and optimization of the IPMSM in the aircraft drive system, and aiming to improve the torque density and reduce the torque ripple. Firstly, the original structure of the IPMSM is given. And then, a fractional slot winding and ∇-type rotor magnetic pole topology are proposed as the optimized IPMSM structure in this article. In addition, the comparison of the original and optimized structure is studied by the simulation. Finally, the performance of an optimized prototype is analyzed by experimental test, and the validity of the design optimization method for proposed IPMSM structure is verified.

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DC Overvoltage Analysis of GFM-controlled Wind Farm Connected via MMC-HVDC System Caused by Receiving-end AC Faults

DC Overvoltage Analysis of GFM-controlled Wind Farm Connecte...

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International Conference on Power Electronics and Motion Control (IPEMC)

作者： Siying Chen Min Cheng Yingbiao Li Jiawei Yu Yihua Zhu Mingkang Wu Jiabing Hu Jianan Yan State Key Laboratory of Advanced Electromagnetic Technology and School of Electrical and Electronic Engineering Huazhong University of Science and Technology China Yunnan Power Grid China CSG Key Laboratory for Power System Simulation (Electric Power Research Institute China Southern Power Grid) State Key Laboratory of HVDC (Electric Power Research Institute China Southern Power Grid) National Energy Power Grid Technology R&D Centre Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System China

ISBN: (数字)9798350351330

ISBN: (纸本)9798350351347

DC overvoltage occurs when short circuit fault exists at the receiving-end and is harmful to the safety of the system where wind farms are connected to the grid through high-voltage direct current (HVDC) transmission based on the modular multilevel converter (MMC). To address this issue, this paper first analyzed the mechanism of the DC overvoltage and innovatively proposed a strategy in which grid-forming-controlled wind farms are integrated into the AC grid through MMC-HVDC, whose sending-end applies grid-following control and constant DC voltage control. However, secondary DC overvoltage appears during the fault recovery stage and is mainly caused by the saturation of the PI controller of constant active power control. Simulations are carried out on a test with MATLAB/Simulink, and results verify the efficacy of the proposed methods in suppressing DC overvoltage that appeared during receiving-end faults and their recovery stage.

关键词： PI control Simulation Power control Wind farms Robustness Wind turbines Safety

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Design of Electric Spindle Control System for High-Grade CNC Machine Tools

Design of Electric Spindle Control System for High-Grade CNC...

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International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification Conference (ESARS-ITEC)

作者： Jinhua Liang Haiping Xu Wei Liu Key Laboratory of Power Electronics and Electric Drive University of Chinese Academy of Sciences Institute of Electrical Engineering Chinese Academy of Sciences Beijing China Institute of Electrical Engineering Chinese Academy of Sciences Beijing China Qilu Zhongke Electric Advanced Electromagnetic Drive Technology Research Institute Jinan China

advanced CNC machine tool is one of the high-end equipment to promote the innovation and development of manufacturing industry, and electric spindle is the core component of CNC machine tool. Control system is the brain of CNC machine tools, responsible for receiving user instructions, sensor signals, feedback signals, after data processing and logical operation, send control instructions to the executive parts, so the design of the control system play a crucial role. This paper first constructs the hardware platform of two central control units, and designs the hardware circuit of DSP system, then constructs the three-layer software structure, and designs the flow chart of the main program, distributes the interrupt resources, and finally designs the flow chart of interrupt and fault protection subroutine. The experimental test shows that the maximum temperature rise of the enclosure of the electrical spindle prototype is 15.6 °C when the no-load 20000 rpm is stable, and the maximum radial runout is 1.5 um during the static test. The control system designed in this paper can meet the high-performance control requirements of electric spindle, and lay a good foundation for the later research of high precision control and holding technology.

关键词： Manufacturing industries Technological innovation Fault protection Transportation Prototypes Control systems Data processing

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Simulation of the positive streamer propagation in SF6/N2 mixtures with different content of SF6 7

Simulation of the positive streamer propagation in SF6/N2 mi...

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7th IEEE International Conference on High Voltage engineering and Application, ICHVE 2020

作者： Luo, Bin He, Henxing Cheng, Chen Wu, Yutong Huang, Yubin Chen, Weijiang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China State Grid Corporation of China Beijing China

ISBN: (纸本)9781728155111

SF6/N2 gas mixture is considered as a practical alternative proposal of SF6 in GIL and GIS. Simulating the positive streamer propagations in different SF6/N2 mixtures assists in the optimization of SF6 ratio in SF6/N2 mixtures and the insulation design of GIL and GIS. This paper presents a fluid dynamic model for the positive streamer propagation in SF6/N2 mixtures. Based on this model, the positive streamer propagations in a 1 mm needle-plate gap in SF6/N2 mixtures with three different content of SF6 are simulated. Through the comparison of space net charge and chemical reaction rate, it is noted that there exists a negative space charge region in the streamer channel. With the increase of the ratio of SF6, the attachment of SF6 will be reinforced, thereby accelerating the accumulation of the negative space charge in the streamer channel. The increased negative space charge inhibits the ionization activity at the streamer head and leads to the increase of the critical ambient field sustaining the continuous propagation of the positive streamer. In SF6/N2 mixtures with high SF6 content, the decrease rate of the ionization activity at the streamer head may overwhelm the increase rate of the attachment rate in the streamer channel, indicating that the cease of the ionization activity is more likely to result in streamer decay in the SF6 mixtures with high SF6 content. © 2020 IEEE.

关键词： Sulfur hexafluoride

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Inherent Switching Reallocated CPS-PWM with Improved Voltage Balancing for MMC

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IEEE Transactions on Power Electronics 2025年

作者： Peng, Li Ying, Yuxuan Wang, Zhen Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Wuhan430074 China

Modular multilevel converter is an attractive solution in medium or high voltage applications, and voltage balancing is one of the most significant technical problems especially for CPS-PWM based MMCs. To solve this problem, in this paper, an inherent switching reallocated CPS-PWM is proposed for MMC. Based on arm current directions, switching states of sub-modules (SMs), voltage sorting and carrier sorting results, proposed method divides SMs and carriers into inserting and bypassing groups for each, enabling switching reallocation within these four co-optimized groups to inherently balance capacitor voltages. This effectively prevents additional switchings. Besides, most computations of the proposed CPS-PWM are logical operations implemented in FPGA, so proposed method can achieve reallocation frequency equal to sampling frequency. Unlike other CPS-PWM based methods for voltage balancing, the inherent switching reallocated CPS-PWM not only has superior converge speed in dynamic processes which accommodate a wide power range, but also has excellent balancing accuracy especially considering capacitance differences. Owing to appropriate reallocation principles, the proposed CPS-PWM has lower switching loss compared to existing carrier reallocation methods. Finally, the feasibility and superiority of the proposed method are validated by simulation and experiment results. © 1986-2012 IEEE.

关键词： Compressed sensing

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