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Smart Grids and Energy Systems (SGES), International Conference on

作者： Zhihong Jiang Guiyuan Liu Kangnan Song Han Li Hao Yang Han Wu School of Electrical Engineering and Information Technology Changchun Institute of Technology Changchun China National Local Joint Engineering Research Center for Smart Distribution Grid Measurement and Control With Safety Operation Technology Changchun China International Joint Research Center for New Energy Power Generation and Network Control Technology of Jilin Province Changchun China

Under the high penetration rate of wind power, the power system puts forward technical requirements for the frequency regulation capability of wind farms. Considering that the frequency response capability of the double-fed induction generator (DFIG) is insufficient, it is proposed to combine energy storage (ES) with wind power for system frequency regulation. Based on the frequency characteristic models of the wind farm and the ES system, this paper establishes a prediction model for the over speed control of the wind farm and a prediction model for the electrochemical energy storage system, and optimizes the active power output of the wind turbine and the energy storage system. The strategy is based on the optimal control of the wind turbine output power and ES power variation, and on this basis, an optimal control model considering the ES state of charge (SOC) and power is designed. The simulation results show that the proposed control strategy can not only effectively suppress grid frequency deviation can also coordinate the ES state of charge and frequency control.

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Study on the Characteristics and Mechanism of Discharge Degradation Products of Epoxy Resin Matrix in Composite Insulators Under Humid Air Environment 19th

Study on the Characteristics and Mechanism of Discharge Degr...

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19th Annual Conference of China Electrotechnical Society, ACCES 2024

作者： Zhiyu, Wan Dandan, Zhang Chao, Gao Ming, Lu Hui, Li Zhenbiao, Li Kexin, Shi School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China Ministry of Education Wuhan430074 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan430074 China Henan Key Laboratory of Power Transmission Line Galloping Prevention and Control Technology State Grid Henan Electric Power Research Institute Zhengzhou450052 China Henan Jiuyu EPRI Electric Power Technology Co. Ltd. Zhengzhou450052 China

ISBN: (纸本)9789819613823

The degradation of the epoxy resin matrix in the core rods of composite insulators is the primary factor leading to decay-like deterioration and fracture accidents. Partial discharge in a humid environment is a critical trigger for this phenomenon. As an organic polymer, epoxy resin is prone to degradation under discharge, producing complex degradation products that can have secondary effects on surrounding materials, further accelerating the decay-like deterioration process. To optimize the formulation and manufacturing process of composite insulator materials and mitigate or even prevent decay-like fractures, it is crucial to study the discharge degradation products and mechanisms of the epoxy resin matrix. In this study, discharge experiments were conducted on anhydride-cured bisphenol A epoxy resin used in composite insulators within a closed humid environment. Changes in chemical functional groups of solid samples before and after discharge were analyzed from the high-frequency region to the fingerprint region. The main components and relative yields of liquid and gaseous discharge products were detected, and the primary reaction mechanisms during the discharge degradation process were thoroughly investigated. Results indicate that partial discharge in humid air induces instantaneous temperature rise and radical action, leading to epoxy resin degradation, generating alcohols and hydroxyl groups, which may increase the material’s hydration capacity and surface conductivity, thereby reducing electric field uniformity. Gaseous products such as methane, acetone, ethylene, and ethyl acetate produced by discharge pyrolysis may exacerbate stress at the core rod and sheath interface, increasing the risk of interfacial damage. Liquid products like nitric acid, carboxylic acids, and acetone may accelerate glass fiber fracture and sheath swelling. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Partial discharges

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Isolated Balanced Charger using Multi-Active Bridge (MAB-IBC)

Isolated Balanced Charger using Multi-Active Bridge (MAB-IBC...

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IEEE Conference on Power Electronics and Renewable Energy (CPERE)

作者： Omar H. Sabry Alaa Eldin Khalil Ahmed El-Shenawy Mostafa S. Hamad Ayman S. Abdel-Khalik Research and Development Center Arab Academy for Science Technology and Maritime Transport El-Alamein Egypt Department of Electrical and control Engineering Arab Academy for Science Technology and Maritime Transport Alexandria Egypt Department of Electrical Engineering Alexandria University Alexandria Egypt

This paper proposes a balanced batteries charger using multi-active bridge-based topology to achieve efficient and active balanced charging for the battery cells within less time. The proposed technique achieves balancing while charging the batteries coping with the universal urge for efficient and fast battery management systems/chargers which have increased significantly along with the emerge of multiple battery powered applications such as electric vehicles and more

关键词： Bridges Battery chargers Renewable energy sources Battery management systems Electric vehicles Power electronics Batteries

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An Additional PSS Design for Grid-Forming Converters Tied to Stiff Grid

An Additional PSS Design for Grid-Forming Converters Tied to...

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Power System and Green Energy Conference (PSGEC)

作者： Zhuoqi Hou Jiangang Lu Zhiwen Yu Ruifeng Zhao Wenxin Guo Meng Zhan State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China Power Dispatching Control Center of Guangdong Power Grid Guangzhou China

ISBN: (数字)9798350365573

ISBN: (纸本)9798350365580

With integration of a large number of power electronic devices into the grid, stability issues are continuously occurring. In this paper, a design method for an additional stabilizer specifically for the instability issues caused by grid-forming converters under stiff grid conditions is proposed. Firstly, a detailed model and a simplified model of the grid-forming converter tied system are established. Borrowing the phase compensation method of power system stabilizer (PSS) for synchronous machines, an additional stabilizer for grid-forming converters is designed. The impact of introduction of additional stabilizer and the variation of parameters on the critical short-circuit ratio (CSCR) of grid-forming converters are analyzed. Finally, the above analysis is verified in Matlab/Simulink. The results show that the proposed design method for the additional stabilizer can effectively increase the CSCR of the grid-forming converter tied system, and enhance the static synchronous stability under stiff grid conditions.

关键词： Green energy Filtering Design methodology Power system stability Stability analysis Mathematical models Power electronics Synchronous machines MATLAB Grid forming

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Weakly Supervised and Semi-Supervised Semantic Segmentation Makes Full Use of a Small Amount of Labeled Data

SSRN

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SSRN 2023年

作者： Zhang, Wenming Li, Yaqian Li, Haibin Wang, Zhe Engineering Research Center Ministry of Education for Intelligent Control System and Intelligent Equipment Yanshan University Qinhuangdao China Key Laboratory of Industrial Computer Control Engineering of Hebei Province Yanshan University Qinhuangdao China School of Electrical Engineering Yanshan University Qinhuangdao066004 China

Semi-supervised and weakly supervised semantic segmentation are very challenging tasks and have been studied in recent years. The purpose is to reduce the high cost of semantic segmentation label production. In this paper, we propose a weakly supervised assistant supervision strategy (ASS), which introduces more semantic segmentation for the shallow network by introducing additional classification tasks to the classification network, and enhances the fusion of shallow features and deep features. In addition, we propose a multi-scale global correlation module (MSG). This module uses the correlation degree of different scale regions to improve the weight of the nondiscriminative part, which solves the problem of insufficient CAMs activation. In most scenarios, weak supervision and semi-supervision are inseparable. We creatively propose a training strategy that integrates semi-supervision and weak supervision, adding pixel-level supervision in the training process of weak supervision to give full play to the role of pixel-level annotation. Extensive experiments on PASCAL VOC 2012 dataset show that our weakly supervised training strategy achieves the state of the art, and the combination of weakly supervised and semi-supervised training strategy can make more effective use of pixel-level labels. © 2023, The Authors. All rights reserved.

关键词： Semantic Segmentation

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Study on dynamic recrystallization kinetics and microstructural refinement of high-strength 36CrNi3MoV steel during hot deformation

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Journal of Materials research and Technology 2025年 36卷 8999-9012页

作者： Anzu Guo Feng Mao Ruxing Shi Yichou Lin Litao Yin Baoning Yu Liujie Xu Chong Chen Hua Yu Ke Gao Shizhong Wei School of Materials Science and Engineering Henan University of Science and Technology Luoyang 471000 China Longmen Laboratory Luoyang 471000 China National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials Henan University of Science and Technology Luoyang 471000 China CITIC Heavy Industries Co. Ltd. Luoyang Henan 471039 China State Key Laboratory of Intelligent Mining Heavy Equipment Luoyang Henan 471039 China

The flow characteristics and grain morphology evolution of 36CrNi3MoV steel were systematically investigated through isothermal hot compression experiments under temperatures of 900–1200 °C and strain rates of 0.001–1 s −1 . The true stress-strain curves revealed that the flow stress increases with rising strain rates and decreasing deformation temperatures. A strain-coupled constitutive equation for flow stress was constructed based on a phenomenological model. Using single-pass compression experimental data, dynamic recrystallization (DRX) volume fraction and DRX grain size models were established, both demonstrating high accuracy in predicting and characterizing the DRX behavior of the studied alloy. Furthermore, hot processing maps at different true strains were developed based on the dynamic materials model (DMM). By partitioning these maps according to power dissipation efficiency and the Prasad instability criterion, the deformation mechanisms in different regions were analyzed through corresponding microstructures. The results revealed that the optimal deformation parameters are a temperature range of 1050–1100 °C and a strain rate range of 0.1–1s −1 . These findings provide theoretical guidance for optimizing hot working processes of high-strength steels.

关键词： 36CrNi3MoV Dynamic recrystallization Constitutive equation Processing map

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Synthesis of symmetrical medium-and long-chain triacylglycerols rich in arachidonic acid at sn-2 position for infant formula

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Food Bioscience 2022年第1期45卷 386-392页

作者： Xuan Jiang Jianhua Huang Yaru Li Ye Wen Shibin Wu Xiuli Xu Zhonghao Chao Hong Zhang Xiaoqiang Zou National Engineering Research Center for Functional Food Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu ProvinceNational Engineering Laboratory for Cereal Fermentation TechnologyState Key Laboratory of Food Science and TechnologySchool of Food Science and TechnologyJiangnan University1800 Lihu RoadWuxi214122JiangsuPR China Joint Laboratory of Functional Food for Healthy Body Fat Loss Chengdu Tianyi Cuisine Nutritious Food Co.Ltd.360 Tianhui RoadHigh-tech ZoneChengduSichuanChina Wilmar(Shanghai)Biotechnology Research&Development Center Co. No.118 Gaodong RoadPudong New DistrictShanghai200137China

Medium-and long-chain triacylglycerols(MLCT)rich in arachidonic acid(ARA)at sn-2 position were synthesized by a two-step enzymatic ***,sn-2 monoacylglycerols(MAG)were synthesized at a temperature of 25℃ by enzymatic *** MAG with 69.42%ARA at sn-2 position were obtained by solvent extraction and low temperature solvent ***,the MLCT rich in ARA at sn-2 position and capric acid(CA)at sn-1,3 positions were produced by enzymatic *** the optimal conditions(MAG:CA=1:3(mol/mol),0.05 MPa vacuum,8% Lipozyme RM IM,5 h,25℃),the content of triacylglycerol was up to 93.60%.The triacylglycerol in the form of C10:0-C20:4-C10:0(including isomers)was about 40.43%.The ARA contents in the total and sn-2 fatty acid composition of the final product were 32.35%and 51.12%,*** rich in ARA at sn-2 position were successfully produced and the product has the potential application for functional food and infant formula.

关键词： Arachidonic acid sn-2 monoacylglycerol Lipase Medium-and long-chain triacylglycerol Infant formula

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Spatial distribution,morphology,and risk assessment of microplastics in sediment from the Pearl River Estuary,China

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Emerging Contaminants 2024年第3期10卷 409-418页

作者： Kaiqiang Xu Asfandyar Shahab Jorg Rinklebe He Xiao Jieyue Li Feng Ye Yanhong Li Dunqiu Wang Michael S.Bank Gangjian Wei College of Environmental Science and Engineering Guilin University of TechnologyGuilin541004China Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology Guilin541004China University of Wuppertal School of Architecture and Civil EngineeringInstitute of Foundation EngineeringWater-and Waste-ManagementLaboratory of Soil-and Groundwater-ManagementPauluskirchstraße 742285WuppertalGermany Institute of Marine Research 5817BergenNorway University of Massachusetts Amherst AmherstMA01003USA State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou510640China

Microplastics(MPs)(64.12%)of detected MPs were<0.85 mm and primarily consisted of pellets(36.84%)and fragments(29.65%).Three polymer types of MPs were identified by Fourier Transform Infrared Spectroscopy(FT-IR)inc... 详细信息

Microplastics(MPs)(<5 mm)are a growing environmental problem and have garnered significant global interest from scientists and policy *** ecosystems are vulnerable to MP pollution,and assessing their sources,fate,and transport in the environment is imperative for marine ecosystem *** for marine sediment are still limited,particularly in the Pearl River Estuary(PRE)ecosystem in ***,we assessed the abundance,characteristics,and risks of MPs in marine sediment from *** abundance ranged from 2.05×10^(3)items·kg^(-1)to 7.75×10^(3)items·kg^(-1)(dry weight),and white and black MPs were the dominant *** majority(>64.12%)of detected MPs were<0.85 mm and primarily consisted of pellets(36.84%)and fragments(29.65%).Three polymer types of MPs were identified by Fourier Transform Infrared Spectroscopy(FT-IR)including polyethylene(PE),polyethylene terephthalate(PET),and polypropylene(PP).Polyurethane(PU)sponge was reported for the first time in this study *** of the surface morphology of typical MPs using Scanning Electron Microscopy(SEM)showed that all MPs exhibited varying degrees of erosion,characterized by cracks,folds,and bumpy *** on type and quantity of MPs and the polymers identified,we assessed and classified the risk of MP contamination in PRE sediment as category Ⅲ,indicating severe ecosystem *** results may serve as an effective model for other estuaries facing similar pollution regimes and provides valuable information for marine sediment risk assessment.

关键词： Microplastics Distributional characteristics Surface morphology Risk assessment Pearl River Estuary

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A Knotted-Ribbon Model for Estimation of Anisotropic Thermal Conductivities of Windings with Rectangular Wires 11

A Knotted-Ribbon Model for Estimation of Anisotropic Thermal...

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11th International Conference on Power Electronics - ECCE Asia, ICPE 2023-ECCE Asia

作者： Sun, Zehui Wang, Qunjing Qian, Zhe Chen, Qixu Deng, Wenzhe Li, Guoli Anhui University School of Electrical Engineering and Automation Hefei230601 China Anhui University National Engineering Laboratory of Energy-Saving Motor & Control Technology Hefei230601 China Anhui University Engineering Research Center of Power Quality Ministry of Education Hefei230601 China Anhui University Anhui Key Laboratory of Industrial Energy-Saving and Safety Hefei230601 China

ISBN: (纸本)9788957083505

Overheating of the windings is one of the major concerns regarding the reliability of motors, generators and transformers. However, thermal modeling of windings is challenging due to the fine and heterogeneous structures. Without adequately addressing the microscopic heat flux field in windings, the commonly used models, even those with conductor insulation accounted for, may give divergent estimations for the equivalent thermal conductivity of windings. Considering the negligible thermal resistance of conductors, a knotted-ribbon model based on the perfect-conductor assumption is proposed for windings formed with rectangular wires, which enables us to derive a closed-form solution to the heat flux field in the impregnation between rectangular wires. From this heat flux solution, the effective thermal resistance of the impregnation, which constitutes the vast majority of that of the whole winding, can then be calculated, based on which a homogenization model is obtained for the anisotropic thermal conductivity of the winding. © 2023 The Korean Institute of Power Electronics.

关键词： Winding

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Ultra-Local Model Based Fixed-Time control for the Wearable Exoskeleton with Prescribed Performance

Ultra-Local Model Based Fixed-Time Control for the Wearable ...

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第42届中国控制会议

作者： Xianlei Zhang Yan Zhang Qing Hu Anjie Yang Xuan Li College of Artificial Intelligence and Data Science Hebei University of Technology Control Engineering Technology Innovation Center of Hebei Province Hebei University of Technology

This paper studies the problem of trajectory tracking control for the wearable exoskeleton system subject to unknown dynamics. An ultra-local model is adopted to describe the dynamic relationship between control input and output. To achieve high-precision fast tracking, a new fixed-time control method is designed. Not only can the convergence time and tracking accuracy be given in advance, but also the complicated modeling process is avoided. A new performance function is constructed and the specified tracking accuracy is achieved within a given time. Through rigorous theoretical analysis, it can be concluded that all signals of the control system are fixed-time convergent, and the tracking error converges to a small neighborhood of the equilibrium within a fixed-time. Finally, the effectiveness of the control scheme is verified through a practical simulation example.

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