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Power Energy Systems and Applications (ICoPESA), International Conference on

作者： Chengbin Chi Shan Liu Qi Liu Fan Li State Key Laboratory of Advanced Power Transmission Technology State Grid Smart Grid Research Institute Co. Ltd Beijing China Beijing Key Laboratory of DC Grid Technology and Simulation State Grid Smart Grid Research Institute Co. Ltd Beijing China State Grid Shanghai Municipal Electric Power Compan Shanghai China

Wind turbines generally adopt the maximum wind energy tracking control strategy, which makes them obtain the best power generation efficiency. However, this makes wind turbines unable to respond to changes in system conditions, provide inertial support for the system, and participate in the primary frequency modulation of the system, which brings challenges to the frequency safety of high-proportion new energy power systems. In order to improve the frequency stability of high-proportion new energy power system and make wind turbines participate in frequency control actively, this paper proposes a primary frequency modulation control strategy based on load reduction for doubly-fed wind turbines. According to the aerodynamic characteristics of variable pitch wind turbine, a coordinated load shedding control strategy combining variable pitch and variable speed operation was proposed to make the wind turbine have active power reserve capacity. A frequency response link is added to the power control, so that the unit can output power to realize inertia and frequency support when the system frequency fluctuates. The simulation results show that the proposed control strategy can improve the system inertia and primary frequency modulation capability in the full wind speed operating domain under the load mutation condition, and improve the frequency stability of the system after the wind turbine is connected to the grid.

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Enhanced Power Synchronization Based Vector Control with Fault Ride Through for VSC-HVDC

Enhanced Power Synchronization Based Vector Control with Fau...

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IEEE International Conference on Power and Power and Renewable Energy (ICPRE)

作者： Rongcai Pan Chunpeng Li Yuexi Yang Xiao Zhou State Key Laboratory of Advanced Power Transmission Technology State Grid Smart Grid Research Institute Co. Ltd Beijing P. R. China Beijing Key Laboratory of DC Grid Technology & Simulation State Grid Smart Grid Research Institute Co. Ltd Beijing P. R. China

The power synchronization based vector control is proposed with the power synchronization controller (PSC) replacing the conventional phase locked loop (PLL) recently. It is reported that the power synchronization unit can have comparable performance of the conventional PLL based vector control. However, the steady state analysis of the PSC control dq frame orientation and the corresponding steady equilibrium points are not discussed. Worse more, fault ride through of the PSC based vector control is not addressed in the related literatures. First, the measurements error on the performance on PSC based vector control is analyzed and the enhanced PSC based vector control is proposed to further reduce the control complexity. Based on the enhanced PSC based vector control, the equilibrium points and the dq frame orientation of PSC based vector control and its comparison with PLL based one are analyzed in the normal operation. After that, the fault ride through strategy is proposed with consideration of equilibrium point. Finally, simulations using PSC based vector control for voltage source converter based high voltage dc transmission station (VSC-HVDC) are carried out to verify the analysis.

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Erratum to:Finite element simulation and experimental test of the wear behavior for self-lubricating spherical plain bearings

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Friction 2024年第7期12卷 1620-1620页

作者： Yahong XUE Jigang CHEN Sumin GUO Qingliang MENG Junting LUO School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China Aviation Key Laboratory of Science and Technology on Generic Technology of Self-Lubricating Spherical Plain Bearing Yanshan UniversityQinhuangdao 066004China Education Ministry Key Laboratory of Advanced Forging and Stamping Technology and Science Yanshan UniversityQinhuangdao 066004China

Erratum to Friction 10(6):803–841(2022)Yahong Xue,Jigang Chen,Sumin Guo,Qingliang Meng&Junting *** element simulation and experimental test of the wear behavior for self-lubricating spherical plain *** 6(3):297–306(2018).https://***/10.1007/s40544-018-0206-x The authors regret that there was an inadvertent error in Fig.10(c)after checking the *** is important to note that the change does not impact the main conclusion of the *** 10(c)on page 304 was selected as the incorrect picture,and the accurate version of Fig.10(c)is provided as below.

关键词： wear Friction bearings

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Analysis and Improvement of the AC-Voltage Control of GFM MMC to Improve the Voltage Stability of AC/DC Hybrid Power Grid

Analysis and Improvement of the AC-Voltage Control of GFM MM...

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IEEE International Symposium on Power Electronics for Distributed Generation Systems (PEDG)

The grid-forming control is regarded as an effective solution for grid-tied converters to operate under weak grid conditions. Currently, most of the grid-forming control strategies are designed for 2-level voltage source converters. The Power loop-AC voltage loop-AC current loop control is usually adopted in these strategies. This control structure highly relies on the AC side filter capacitor. However, in high-voltage situations, the modular multilevel converter, which has no AC side filter capacitor, is commonly adopted. The integral effect of the filter capacitor in the original control path is replaced by the differential effect of the grid impedance, which worsens the performance of AC voltage control. To solve this problem, the steady-state model of MMC using grid-forming control is established. Based on this model, two improved AC-voltage control strategies are proposed in this paper. simulation results in PSCAD/EMTDC show that the proposed control realizes desired dynamic control of the DC voltage.

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Auto-focused Sparse Bayesian Learning for ISAR Imagery Based on Spike-and-Slab Prior Via Variational Approximation 10

Auto-focused Sparse Bayesian Learning for ISAR Imagery Based...

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10th International Conference on Control, Automation and Information Sciences, ICCAIS 2021

作者： Sun, Weitian Yang, Lei Dou, Yuchen Li, Xuan Fang, Cheng Civil Aviation University of China Tianjin Key Laboratory for Advanced Signal Processing Tianjin China Macalester College Saint Paul United States China Greatwall Technology Group Co. Ltd Shenzhen China

ISBN: (纸本)9781665440295

For inverse synthetic aperture radar (ISAR) imagery, the scatterers of target of interest are inherently sparse in spatial domain. In order to encode the sparsity, the sparse Bayesain model is a popular choice as a statistical manner, where Laplace distribution is imposed on the signal. Meanwhile, the sparse Bayesian model provides a confidential knowledge in the result. Due to the inaccurate compensation of the translational motion of interested target, the phase error correction is incorporated in the sparse Bayesian model to achieve high-resolution for ISAR imaging. In this papar, a novel antofocus sparse Bayesian Learning based on the spike-and-slab prior (SSP-AFSBL) is proposed, which can induce and enhance the sparse feature more flexibly. Due to the nonconjugacy of the likelihood and prior, a hierarchical Bayesian model is performed to provide the full Bayseian inference for the sparse coefficients. To avoid the calculation of a multidimensional integral, the variational Bayesian (VB) approximation is adopted to derive the analytical solution to hyperparameters. Finally, qualitative and quantitative analysis based on simulated and raw datasets have demonstrated the effectiveness of the proposed algorithm. © 2021 IEEE.

关键词： Inverse synthetic aperture radar

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核子电磁形状因子振荡行为的新视角

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Science Bulletin 2023年第22期68卷 2729-2733,M0005页

作者：杨勤鹤郭棣戴凌云 Johann Haidenbauer 康现伟 Ulf-GMeiner School of Physics and Electronics Hunan UniversityChangsha 410082China Hunan Provincial Key Laboratory of High-Energy Scale Physics and Applications Hunan UniversityChangsha 410082China Institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron PhysicsForschungszentrum JülichJülich D-52425Germany Key Laboratory of Beam Technology of the Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of Radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China Helmholtz Institut für Strahlen-und Kernphysik and Bethe Center for Theoretical Physics Universität BonnBonn D-53115Germany Tbilisi State University Tbilisi 0186Georgia

本文研究了质子和中子的类时电磁形状因子.作者基于手征有效场论,通过求解李普曼-施温格方程得到了核子-反核子对散射振幅.以此为输入,利用扭曲波恩近似方法描述了核子末态相互作用,计算了正负电子湮灭到正反核子对的过程.通过拟合相移... 详细信息

本文研究了质子和中子的类时电磁形状因子.作者基于手征有效场论,通过求解李普曼-施温格方程得到了核子-反核子对散射振幅.以此为输入,利用扭曲波恩近似方法描述了核子末态相互作用,计算了正负电子湮灭到正反核子对的过程.通过拟合相移、截面以及微分截面等实验数据,定下了有效场论的未知耦合常数.进一步研究发现,可以利用两个分数振荡振子来描述核子电磁类时形状因子的振荡行为:一个表现为过阻尼振荡,在阈值附近占主导地位;另一个类似于欠阻尼振荡,在高能区起到重要作用.这种振荡行为对理解硬光子诱导的核子内部极化电荷的分布起着至关重要的作用.

关键词： Electromagnetic form factors Fractional oscillator Chiral effective field theory Lippmann-Schwinger equation Distorted wave Born approximation

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AMAS: A DNN-Based Automatic Manhours Approval System

AMAS: A DNN-Based Automatic Manhours Approval System

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Mechanical, Automation and Electrical Engineering (CMAEE), International Conference on

作者： Yunfei Jia Hao Lu Debin Hu Tianjin Key Laboratory for Advanced Signal Processing Civil Aviation University of China Tianjin China Suzhou Weizhong Data Technology Co. Ltd Suzhou China

Manhours estimation and automatic approval plays an important role in project scheduling and reducing the development cost for factory. Traditional approaches usually have some limitations, such as technical text formatting limitations and industry-specific limitations. This paper presents a software system that estimates the manhours and approves the technology texts that have been submitted. Firstly, we collect a technology texts dataset and complement the dictionaries. Secondly, the word2vec is used to extract the features implicated in the technology text, and a DNN (deep neural network) model is proposed to estimate the manhours. Finally, an Odoo-based software system is developed, which provides the estimation manhours and approves automatically of the submitted technology texts. The advantages of approach in which is proposed in this paper is that, it has less limitations on the format of submitted technology texts. And, it can be used for various production technology.

关键词： Training Industries Electrical engineering Job shop scheduling Software algorithms Neural networks Estimation

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Evaluation on elevated-temperature stability of modified 718-type alloys with varied phase configurations

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International Journal of Minerals,Metallurgy and Materials 2020年第8期27卷 1123-1132页

作者： Zhan Qiao Chong Li Hong-jun Zhang Hong-yan Liang Yong-chang Liu Yong Zhang State Key Lab of Hydraulic Engineering Simulation and Safety School of Materials Science&EngineeringTianjin UniversityTianjin 300354China Key Laboratory of the Ministry of Education for Modern Metallurgy Technology North China University of Science and TechnologyTangshan 063210China Science and Technology on Advanced High Temperature Structural Materials Laboratory AEEC Beijing Institute of Aeronautical MaterialsBeijing 100095China

Inconel 718 is a Ni–Fe-based superalloy widely used in aerospace engines because of its excellent mechanical ***,the inferior stability of theγ″phase limits the application of Inconel 718,which coarsens rapidly at temperatures greater than 650°*** improving the temperature tolerance of Inconel 718 requires optimization of the phase configuration via modification of the alloy’s chemical *** the aforementioned objective,this work was conducted to study the precipitation behavior and thermal stability of the strengthening phases with various structures in modified Inconel 718 alloys by tailoring the Al/Ti *** increasing Al/Ti ratio,three particle configurations were formed:γ′/γ″composite,isolatedγ′,andγ′/γ″/γ′composite *** results of aging tests demonstrate that the isolatedγ′and theγ′/γ″/γ′composite structure exhibited better thermal stability at temperature as high as 800°*** isolatedγ′exhibited a reduced coarsening rate compared with theγ′/γ″/γ′composite particles because the isolatedγ′phase was rich in Al,Ti,and ***,theγ′/γ″composite particles coarsened and decomposed rapidly during aging at temperatures greater than 700°C because of the lower stability resulting from the larger number ofγ″*** obtained results provide necessary data for the compositional optimization of novel 718-type alloys.

关键词： Inconel 718 structure thermal stability interface

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Evaluation of Automobile Design Scheme Based on Improved Grey Situation Decision Method

Evaluation of Automobile Design Scheme Based on Improved Gre...

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Mechanical, Automation and Electrical Engineering (CMAEE), International Conference on

作者： Yunfei Jia Qingsong Tian Debin Hu Tianjin Key Laboratory for Advanced Signal Processing Civil Aviation University of China Tianjin China Suzhou Weizhong Data Technology Co. Ltd Suzhou China

Evaluation of design scheme for new types of cars refers to multiple attribute comprehensive evaluation. In this paper, an improved grey-situation decision-making method is proposed. The advantage of our method lies in both the preference of decision maker and the objectiveness implicated in the data are incorporated. Firstly, AHP is exploited to build hierarchy and assign subjective weights to each attribute. This can incorporate the decision maker's successful experiences into comprehensive evaluation in a fine-grained way. Secondly, the Grading system is used to enhance the contribution of significant attributes with almost equal value. On the contrary, traditional gray-situation method usually overlooks the contribution of almost equal attributes, even if these attributes are greatly weighted at previous step. Finally, the effectiveness of the method is validated through a real-world automotive design scheme. Our method can be easily generalized and applied to wider domains.

关键词： Electrical engineering Automation Design methodology Analytic hierarchy process Automobiles Automotive engineering

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Three-dimensional Anatomically Realistic Numerical Head Model Construction based on T1-weighted MRIs for Microwave Hemorrhagic Stroke Imaging

Three-dimensional Anatomically Realistic Numerical Head Mode...

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IEEE MTT-S International Microwave Workshop Series on advanced Materials and Processes for RF and THz Applications (IMWS-AMP)

作者： Qinwei Li Lunxiao Wang Xiaoguang Lu Ming Yu Tianjin Key Laboratory for Advanced Signal Processing Civil Aviation University of China Tianjin China Technology Institute of Systems Engineering Academy of Military Sciences Tianjin China

A 3-D anatomically realistic numerical brain model construction process based on real magnetic resonance imaging (MRI) images is presented in this paper. This phantom serves as a simulation experimental verification basis for later microwave detection of intracranial hemorrhage. This numerical model is derived from the T1-weighted MRIs of the patients. The MRI case images were processed by separating, labeling, and categorizing each biological brain tissue. Each slice is transformed into uniform grids mapping different brain tissues' dielectric properties. The 3-D finite-difference time-domain (3D-FDTD) numerical phantom verifies the feasibility of the proposed construction method. Compared with earlier models, the construction of this model follows the real human brain tissue structure, giving a more accurate experimental platform for various imaging simulation techniques.

关键词： Solid modeling Magnetic resonance imaging Biological system modeling Phantoms Brain modeling Microwave theory and techniques Numerical models

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