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5th IEEE Conference on Energy Internet and Energy System Integration, EI2 2021

作者： Lai, Qinghua Zhang, Zhe Han, Jiexiang Yin, Xianggen State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781665434256

In the short-circuit current calculation of power grid, the renewable energy sources (RES) cannot use the equivalent method similar to the traditional synchronous generator because of the access mode and low voltage ride through control strategy. Therefore, it is difficult to solve the short circuit current directly by the traditional fault analysis method. According to the control strategy and fault characteristics of different types of RES, the equivalent calculation model of RES is obtained, especially the equivalent calculation model of doubly fed power sources when the negative sequence short-circuit current is not zero. On this basis, the node voltages equation and the iterative calculation method of the short-circuit current for the power grid with different types of RES are given. Then, an experimental platform with RES is established. The correctness of the equivalent calculation model and the iterative calculation method of short-circuit current are verified by short-circuit experiment. © 2021 IEEE

关键词： Short circuit currents

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Multi-objective Optimization Strategy for Intelligent Charging and Discharging Station of Electric Vehicles in the Distribution Network 4

Multi-objective Optimization Strategy for Intelligent Chargi...

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4th IEEE China International Electrical and Energy Conference, CIEEC 2021

作者： Xu, Zhiwen Chen, Changsong Chen, Haowen Zhang, Jingyue Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (纸本)9781728171494

The safe operation of power grid is negatively affected by disorderly charging of electric vehicles (EVs), and the operating cost of the EVs' charging station is also increased by disorderly charging. To solve this problem, this paper proposes a multi-objective optimization strategy for intelligent charging and discharging station (ICDS) of EVs in the distribution network, which considers the load/energy storage characteristics of EVs. An optimization model including ICDS, distribution network and distributed generation (DG) is proposed, and grid power flow of the distribution network is considered as the constraint. In the model, the inner-layer model is aimed at a lower total daily operating cost of the ICDS by optimizing the EVs' charge- discharge power of each moment, and the outer-layer model is aimed to minimize the loss of the distribution network by optimizing the location of the node that ICDS is connected to the distribution network. Both the economy of the ICDS and the security of the distribution network are all improved in the multi- objective double-layer optimization model. Particle swarm optimization (PSO) is applied for the iterative solution and global optimization. Finally, a modified IEEE 33-node system is performed to prove the rationality and feasibility of the model. © 2021 IEEE.

关键词： Operating costs

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Optimization Design of Coated Armature in electromagnetic Railgun Based on Multi-objective Genetic Algorithm

Optimization Design of Coated Armature in Electromagnetic Ra...

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Pulsed Power Conference, International Conference on High-Power Particle Beams and International Symposium on electromagnetic Launch technology (EAPPC/BEAMS/EML), Euro-Asian

作者： Xuan Xu Lixue Chen Shengqin Xu Wenhao Zhang Bingxuan Zhao Tingyun Xiao State Key Laboratory of Advanced Electromagnetic Technology Key Laboratory of Pulsed Power Technology Ministry of Education School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9789038661353

ISBN: (纸本)9798350352733

The electromagnetic railgun is an advanced launch device that accelerates the armature to ultra-high speed through electromagnetic force. The contact between the armature and the two rails is a kind of ultimate sliding electrical contact beyond high pulse current, high speed, and high contact pressure. It leads to excessive local electromagnetic field distribution at the contact interface, which is not conducive to launch performance. In this paper, armatures of different coated structures are considered to improve the electromagnetic field distribution. First, the characteristic-difference scheme based on the bilinear interpolation method is presented to solve the electromagnetic governing equation of the railgun when launching armatures of different coated structures. Second, an optimization design based on NSGA-II is constructed to obtain the Pareto optimal solution set, and an optimized armature of coated structure that brilliantly meets the design objectives is selected. Finally, numerical calculations are conducted based on the optimized parameters to verify the effectiveness of the multimaterial coated armature structure. Results show that the maximum current density of the optimized armature is reduced by 54% compared to the uncoated armature, current diffusion time at the contact interface along the x-direction is shortened by 80 μs, and the penetration depth of the current along the ydirection at the armature-rail contact interface is increased by 1.6 mm, which significantly optimizes the current distribution during the launch process of the electromagnetic railgun.

关键词： Rails Interpolation Contacts Railguns Armature Current distribution electromagnetic fields electromagnetics Current density Optimization

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Subsynchronous Oscillation Research of LCC-HVDC Receiving End System with Large-scale Renewable Power Generation 5

Subsynchronous Oscillation Research of LCC-HVDC Receiving En...

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5th IEEE International Electrical and Energy Conference, CIEEC 2022

作者： Du, Buyang Zhu, Jianhang Hu, Jiabing Guo, Zeren Shao, Dejun Xu, Youping Shi, Mengxuan Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Wuhan China Central China Branch of State Grid Corporation of China Wuhan China

ISBN: (数字)9781665411042

ISBN: (纸本)9781665411042

The line-commutated-converter (LCC) based high voltage direct current (HVDC), and renewable power generation have developed rapidly in central China. However, the risk of subsynchronous oscillation (SSO) for this typical LCC-HVDC receiving end system with large-scale renewable power generations (LCCre-RPGs) is unclear. In this paper, a small-signal model of LCCre-RPGs is constructed. The renewable power generations are simulated by a permanent magnet synchronous generator (PMSG) and a doubly-fed induction generator (DFIG). Then, the interaction between LCC-HVDC and renewable power generations is analyzed through the eigenvalue analysis and participation factor analysis. Moreover, the interaction may lead to the risk of SSO. Finally, the influence of controller parameters on the SSO modes is investigated in detail, which provides theoretical support for optimizing relevant parameters. The time-domain simulation of the original nonlinear model verifies the above analysis results. © 2022 IEEE.

关键词： Factor analysis

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Research on inductance gradient of electromagnetic railgun based on eddy current field analysis

Research on inductance gradient of electromagnetic railgun b...

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Pulsed Power Conference, International Conference on High-Power Particle Beams and International Symposium on electromagnetic Launch technology (EAPPC/BEAMS/EML), Euro-Asian

作者： Shengqin Xu Lixue Chen Wenhao Zhang Bingxuan Zhao Tingyun Xiao State Key Laboratory of Advanced Electromagnetic Technology Key Laboratory of Pulsed Power Technology Ministry of Education School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9789038661353

ISBN: (纸本)9798350352733

Inductance gradient has a significant effect on muzzle kinetic energy and launch efficiency in electromagnetic railgun. Inductance gradient is determined by the current distribution in the armature and rail, transient skin effect, velocity skin effect, and proximity effect are the main physical mechanisms affecting the current distribution of electromagnetic railgun. Additionally, the structure and size of the rail also have an impact on current distribution. In order to analyze inductance gradient, the control equation of the electromagnetic railgun is analyzed, and the 3D motion model of the electromagnetic railgun is established. The distribution of the 3D current and magnetic field under the influence of the velocity skin effect is calculated, and then the time-varying curves of the inductance gradient during the whole launch process are drawn, curves show that the inductance gradient trend when velocity skin effect is considered is opposite to that not considered. At the same time, the inductance gradient under different rail structures is compared by simulation calculation, the results show that the inductance gradient of the rectangular rail is larger than that of the T-shaped rail and the arc-shaped rail. Finally, the effect of the dimensions of the rectangular rail on the inductance gradient is investigated, and the results show that the inductance gradient of the rectangular rail decreases gradually with the increase of the rail width, and increases and then decreases with the increase of the rail height.

关键词： Rails Inductance Solid modeling Three-dimensional displays Railguns Market research Current distribution Mathematical models electromagnetics Skin effect

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PLL SYNCHRONIZATION TRANSIENT STABILITY ANALYSIS OF VSC UNDER SINGLE-PHASE-TO-GROUND AC FAULT 10

PLL SYNCHRONIZATION TRANSIENT STABILITY ANALYSIS OF VSC UNDE...

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10th Renewable Power Generation Conference, RPG 2021

作者： Lin, Chensheng Li, Yingbiao Hu, Jiabing State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781839536069

Controlling negative sequence currents at zero is feasible in practice, which can improve the performance of voltage-source converters (VSCs) during asymmetric ac faults. VSCs are usually synchronized with the grid via the phase-locked loop (PLL) However, the synchronization stability is affected by the negative sequence current of VSCs. Hence, this article analyses the PLL transient stability of PLL-synchronized VSCs during single-phase-to-ground ac fault. The parametric impacts of the phase-locked loop and the effect of positive/negative sequence current on synchronization stability are revealed analytically, via employing the phase portrait approach. It is revealed that the loss of synchronization (LOS) possibly arises if VSCs suppress negative sequence current to zero under single-phase-to-ground ac faults. Time-domain simulations are performed in Matlab/Simulink, and the obtained results validate the theoretical findings. © The Institution of engineering and technology.

关键词： Phase locked loops

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Numerical characteristics of DC breakdown and paschen curve of CF3I-N2mixtures at low pressure 5

Numerical characteristics of DC breakdown and paschen curve ...

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2024 5th International Conference on Electrical, Electronic Information and Communication engineering, EEICE 2024

作者： Wu, Yifan Wu, Hao Gao, Jiamao Yu, Shimin Chen, Zhipeng Jiang, Wei Wang, Zhijiang International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and Technology Sch Elect & Elect Engn Huazhong University of Science and Technology Wuhan430074 China State Grid Jiangsu Electric Power Co Taizhou225300 China School of Electronics and Information Engineering Hubei University of Science and Technology Xianning437100 China School of Physics Huazhong University of Science and Technology Wuhan430074 China

In this study, the DC breakdown characteristics of CF3I-N2 mixtures at low pressure are investigated and compared with those of pure CF3I to assess their insulating properties. Utilizing the particle-in-cell/Monte Carlo collisions (PIC/MC) model, we explore the breakdown process in detail, analyzing electron and ion kinetics across various phases. Our findings reveal that the CF3I-N2 mixture exhibits a faster breakdown rate than pure CF3I but requires more time to achieve a steady state. Additionally, we examine the Paschen curve of CF3I-N2 at varying pressures, discovering that the insulating performance improves with higher CF3I proportions at increased pressures. This study contributes to understanding the insulating behavior of CF3I-N2 mixtures, offering insights for their application in environmentally friendly high-voltage insulation technologies. © Published under licence by IOP Publishing Ltd.

关键词： Insulation

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Sustainable Lignin-Derived Carbon as Capacity-Kinetics Matched Cathode and Anode towards 4.5 V High-Performance Lithium-Ion Capacitors

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Energy & Environmental Materials 2023年第4期6卷 98-105页

作者： Fangyan Liu Pengfei Lu Ying Zhang Feng Su Liangzhu Zhang Shuanghao Zheng Xiong Zhang Fangyuan Su Yanwei Ma Zhongshuai Wu State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Dalian National Laboratory for Clean Energy Chinese Academy of SciencesDalian 116023China Anhui Key Laboratory of Spin Electron and Nanomaterials School of Chemistry and Chemical EngineeringSuzhou UniversitySuzhou 234000China University of Chinese Academy of Sciences Beijing 100049China CAS Key Laboratory of Carbon Materials Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China Institute of Electrical Engineering and Advanced Electromagnetic Drive Technology Qilu ZhongkeJinan 250013China

The Li-ion capacitors(LICs)develop rapidly due to their double-high features of high-energy density and high-power ***,the relative low capacity of cathode and sluggish kinetics of anode seriously impede the development of ***,the precisely pore-engineered and heteroatomtailored defective hierarchical porous carbons(DHPCs)as large-capacity cathode and high-rate anode to construct high-performance dual-carbon LICs have been *** DHPCs are prepared based on triple-activation mechanisms by direct pyrolysis of sustainable lignin with urea to generate the interconnected hierarchical porous structure and plentiful heteroatominduced *** from these advanced merits,DHPCs show the well-matched high capacity and fast kinetics of both cathode and anode,exhibiting large capacities,superior rate capability and long-term *** experimental and computational results demonstrate the strong synergistic effect of pore and dopants for Li ***,the assembled dual-carbon LIC exhibits high voltage of 4.5 V,high-energy density of 208 Wh kg^(−1),ultrahigh power density of 53.4 kW kg^(−1)and almost zerodecrement cycling ***,the full device with high mass loading of 9.4 mg cm^(−2)on cathode still outputs high-energy density of 187 Wh kg^(−1),demonstrative of their potential as electrode materials for high-performance electrochemical devices.

关键词： capacity-kinetics matching defective hierarchical porous carbons high mass loading high power density Li-ion capacitors

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A Temperature Monitoring Method for Power Electronic Converter Based on Infrared Image and Object Detection Algorithm 4

A Temperature Monitoring Method for Power Electronic Convert...

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4th IEEE China International Electrical and Energy Conference, CIEEC 2021

作者： Yang, Hongcheng Chen, Yu Kang, Yong State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Wuhan China

ISBN: (纸本)9781728171494

Power electronic converters are more and more widely used, and abnormal temperature of converter components is the most important factor of converter failure. In order to improve the reliability of the converter design, it is necessary to monitor the temperature of key components in the converter during the prototype test stage. The temperature measurement method of infrared thermal images has rich temperature information, wide coverage, and does not affect the original circuit design. It is widely used in circuit temperature measurement occasions. However, in the current automatic temperature measurement methods, it is necessary to manually establish a standard matching template for the infrared thermal image of the circuit to be tested, which indicates a large workload and poor versatility. This paper proposes a method for fully automatic temperature monitoring of converter components. This method is based on a deep learning target detection algorithm, which can automatically identify the type of converter components, obtain partial infrared thermal images of components through heterogeneous image registration, and achieve accurate component temperature monitoring. The advantages of this method are: 1) there is no need to manually establish a standard template for each converter, and the versatility is good;2) it is fully automatically when the monitoring the temperature of converter components without manual intervention;3) it is easy to implement and promote due to low cost of hardware system. Finally, the experimental results verify the feasibility and accuracy of this method. © 2021 IEEE.

关键词： Object detection

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Effects of Atmospheric Pressure Plasma in the Treatment of Experimental Periodontitis in Beagle Dogs

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Current Medical Science 2022年第5期42卷 1079-1087页

作者： Xue-zhi TANG Jia-yin LI Qi SHI Han-yong ZHANG Zhi-xiang ZHANG Ke SONG Xin-pei LU Ying-guang CAO Tian-feng DU Department of Stomatology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan430074China Department of Stomatology The First Affiliated Hospital of Zhengzhou UniversityZhengzhou450052China

Objective The specific objective of this study was to evaluate the effects of atmospheric pressure plasma(APP)in the treatment of experimental periodontitis in Beagle *** The APP jet was diagnosed using optical emission spectroscopy and laser-induced fluorescence *** Beagles received stainless steel ligatures to establish experimental periodontitis *** teeth in the control group were subjected to conventional root surface debridement(RSD)and chlorhexidine *** APP group also started with RSD and was then subjected to plasma *** analyses including plaque index,modified sulcus bleeding index,pocket depth and attachment loss(AL),as well as cone-beam computed tomography(CBCT)analysis,were performed at baseline,4th week,8th week and 12th week after *** The results showed that typical reactive oxygen and nitrogen species were found in the full spectrum and the gas temperature of APP was close to room *** highest concentrations of hydroxide and oxygen were obtained at 5 mm away from the *** both groups,all values in clinical examinations were significantly lower(P<0.05)at 12th week after treatment than those at *** the 12th week,the AL in clinical examinations and the bone loss in CBCT images in the APP group were significantly lower than those in the control group(P<0.05).The hematoxylin-eosin staining showed more renascent alveolar bone in the APP group than in the control *** These findings suggested that APP has profound potential for use as an adjunct approach for periodontitis treatment.

关键词： canine plasma biofilms periodontitis therapeutics

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