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2022 IEEE International Conference on High Voltage Engineering and Applications, ICHVE 2022

作者： Ouyang, Liangxuan Wang, Feipeng Chen, Xingyu Song, Chao State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China Jiangsu Shuangjiang Energy Technology Co Jiangsu China

ISBN: (数字)9781665407502

ISBN: (纸本)9781665407502

Transformers will be subjected to electrical, thermal, and mechanical stresses during operation, causing decomposition of the insulation materials and consequently generating gas in the oil. Early transformer faults including electrical faults can be detected in time through DGA (Dissolved Gas-in-oil Analysis) which can reflect the state information of insulating oil transformers. Recently, the application of synthetic insulating oil in large power transformers could increase due to excellent fire resistance, environmental protection, strong oxidation stability, etc. Due to the differences in molecular structure between synthetic ester insulating oils and mineral insulating oils as well as natural ester insulating oils, there are differences in the characteristics of dissolved gas in the oil produced under electrical faults, resulting in different limits of dissolved gas in the oil under normal and fault conditions. In order to ensure the safe and reliable operation of synthetic ester insulating transformers, this paper reviews the analysis on faulty gas production of synthetic ester insulating oil and summaries the commonly used diagnostic methods for synthetic insulating oil under electrical faults. © 2022 IEEE.

关键词： Esters

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Application of Deep Learning Method to Estimate Bottomhole Pressure Dynamics of Oil Wells 32

Application of Deep Learning Method to Estimate Bottomhole P...

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32nd IEEE International Symposium on Industrial Electronics, ISIE 2023

作者： Cheng, Haibo Li, Shichao Zeng, Peng Vyatkin, Valeriy State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang China Key Laboratory of Networked Control Systems Chinese Academy of Sciences Shenyang China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences Shenyang China Luleå University of Technology Electrical and Space Engineering Department of Computer Science Luleå Sweden Aalto University Department of Electrical Engineering and Automation Helsinki Finland

ISBN: (纸本)9798350399714

Surrogate models, which have become an effective and popular method to close loop reservoir management problems, use a data-driven approach to predict dynamic injection and production wells parameters and optimize waterflooding development. In this study, a deep learning-based surrogate model method is proposed to estimate bottomhole pressure (BHP) of production wells in waterflooding reservoirs. Bidirectional long short-term memory (BiLSTM) network, as an efficient deep learning approach, is applied to BHP estimation using fluctuation data. Extended Fourier amplitude sensitivity test (EFAST) method is employed to analyse the influence of different input factors on BHP dynamics, and a reduced dataset is rebuilt to predict BHP parameter based on BiLSTM-EFAST algorithm. The estimation results are tested on a dataset from Volve oilfield in North Sea, and compared with other deep learning methods. The test results indicate that the proposed method can achieve higher prediction accuracy. A reduced dataset-based approach provides a new attempt to reduce model complexity and improve calculation speed for big data-driven surrogate model in oil and gas industry. © 2023 IEEE.

关键词： Long short-term memory

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A Look-Up Table Based Inverter Nonlinearity Compensation Method Considering Parameter Inconsistency of Upper and Lower Bridge Arms

A Look-Up Table Based Inverter Nonlinearity Compensation Met...

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IEEE International Symposium on Industrial Electronics (ISIE)

作者： Yonghe Huang Dianguo Xu Yan Xu Yong Yu Junyu Zhao Xubo Gong School of Electrical Engineering and Automation Harbin Institute of Technology Harbin China The State key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin China

ISBN: (数字)9798350394085

ISBN: (纸本)9798350394092

In motor drive systems, voltage source inverter (VSI) nonlinearity will produce voltage error, cause current harmonics, and affect the control performance. Among the VSI nonlinearity factors, the parasitic capacitance is the fundamental cause of the nonlinear relationship between voltage error and phase current. If the parameter inconsistency of the upper and lower bridge arm is not considered, the voltage error is an odd function. However, in practical applications, the parameters of the upper and lower bridge arms are usually slightly different, and the voltage error will no longer be an odd function. Considering the influence of parameter inconsistency, this article proposes an accurate look-up table (LUT) based method for VSI nonlinearity compensation. By injecting positive staircase current and negative staircase current separately in self-commissioning process, an accurate voltage error LUT is obtained through numerical fitting methods. The proposed method does not require any parameter of power devices. Experimental results verify the effectiveness of the proposed method.

关键词： Industrial electronics Motor drives Accuracy Voltage source inverters Fitting Bridge circuits Table lookup

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Theoretical Modeling and Performance Analysis on the Linear Electromagnetic Actuator with High Nonlinear Dynamic Negative Stiffness

SSRN

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SSRN 2024年

作者： Wang, Chuchao Lu, Shizhou Liu, Xiaohan Mo, Wenyin Zhang, Bin Li, Kai Sun, Lining Mechanical Electrical & Information Engineering Shandong University Weihai264209 China School of Mechanical Engineering Dalian University of Technology Dalian116081 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China

Electromagnetic mechanisms are introduced to adjust the stiffness and improve the performance of mechanical systems, which have been widely researched. In this paper, the transient performance of a novel linear solenoid elastic actuator with higher nonlinear negative stiffness and speed by introducing the negative stiffness mechanism is analyzed and predicted. The actuator can achieve an initial theoretical stiffness of -20.96 N/m at 1 A current and a maximum stroke of 9 mm in 0.5 s. The performance indicators including peak time, overshoot, and steady-state displacement are obtained through electromagnetic-mechanical coupled modeling. The influence of system parameters including natural frequency, equivalent stiffness and damping coefficient on performance indicators is also studied. First, the approximate analytical model of the electromagnetic force is derived by constructing an innovative magnetic field distribution model. Second, the nonlinear vibration equation is solved theoretically to obtain the analytical results of the performance indicators and system parameters. Finally, the transient displacements and performance indicators obtained from the analytical model, the numerical model established in Simulink software and the simulation model obtained in Adams software are compared. The maximum errors of the peak time, overshoot and stable displacement through the analytical model and experiment are 2.56 ms, 9.37% and 0.32 mm, respectively. The theoretical and experimental results show the nonlinear effects of input currents on performance indicators and system parameters. The overshoot has a strong positive following feature on the damping coefficient, but the vibration frequency mainly depends on the equivalent stiffness of the system. This research provides a reference for the transient solution of nonlinear electromagnetic-dynamic coupling models and performance improvement of linear electromagnetic actuators. © 2024, The Authors. All rights reserved.

关键词： Stiffness

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Model Design and Concept of Operations of Standard Interface for On-orbit Construction

Model Design and Concept of Operations of Standard Interface...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Jingdong Zhao Zirui Wang Ziyi Liu Liangliang Zhao Qifan Duan Hong Liu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Chang Guang Satellite Technology Co. Ltd. Changchun China Beijing Honor Device Co. Ltd. Beijing China

ISBN: (数字)9798350384574

ISBN: (纸本)9798350384581

The construction of large-scale space facilities requires the use of on-orbit construction technology. However, several of its key components, such as standard interface design, compliant control methods, and path planning for multi-branch robots, still need improvement before practical application. This paper presents a comprehensive solution for on-orbit construction tasks, encompassing a novel standard interface, docking control method, and path planning method for space multi-branch robots. Firstly, a novel standard interface is introduced, which features multiple mating modes and a lightweight design. Additionally, a compliant docking method is provided to generate lower contact forces along the Z-direction. Furthermore, for four-armed space robots, a hierarchical planning method is proposed, which innovates in environment map construction and locomotion planning. Specifically, the closed-form Minkowski sum method is employed to solve the robot’s free space, and a concise locomotion method is elucidated based on transition support points. Finally, simulations and experiments are conducted.

关键词： Visualization Machine vision Prototypes Aerospace electronics Path planning Planning Task analysis

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Optimal Scheduling of Pumped Storage Power Station with Double-Fed Variable Speed Unit Based on Reservoir Regional Operation Strategy 4

Optimal Scheduling of Pumped Storage Power Station with Doub...

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4th Asia-Pacific Conference on Communications technology and Computer Science, ACCTCS 2024

作者： Ma, Yuhan An, Yining Ge, Xiaohui Zhao, Bo State Grid Zhejiang Electric Power Co. Ltd. Research Institute Zhejiang Hangzhou China Northeast Electric Power University Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology Jilin Jilin China

ISBN: (纸本)9798350359985

The conventional pumping unit lacks the ability to continuously adjust input power during pumping operations, and exhibits poor adaptability when integrating new energy sources into the grid. In this study, we propose a novel 'domain operation' strategy that allocates resources based on real-time reservoir conditions across all levels of hydropower stations, while optimizing operations through the implementation of doubly fed units. © 2024 IEEE.

关键词： Hydroelectric power

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Prediction and Analysis of Large-Scale Stock Market Risk Correlation Structure

Prediction and Analysis of Large-Scale Stock Market Risk Cor...

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High Performance and Smart Computing (HPSC), IEEE International Conference on

作者： Wang Ting Pan Zhijie Zheng Yanting Key Laboratory of System Software and State Key Laboratory of Computer Science Institute of Software CAS Beijing China School of Economy Beijing Technology and Business University Beijing China

ISBN: (数字)9798331596637

ISBN: (纸本)9798331596644

The prediction of the high-dimensional dependence structure among global stock markets is an advanced topic in financial risk management. However, the complex structure characterized by high dimensionality, nonlinearity, and asymmetry, presents significant challenges for conventional financial models (e.g. Autoregressive Moving Average Model) to systematically and efficiently predict and analyze large-scale cross-market correlation structures. The original program for preprocessing the correlation structure decomposition across 36 countries was optimized, enabling it to scale up to hundreds of threads in parallel. It achieved an acceleration of over 25.88 times on 30 threads compared to the original program. The advancement of deep learning technology has provided a solution to this issue. By constructing models such as Recurrent Neural Networks (RNN), Long Short-Term Memory Networks (LSTM), and Gated Recurrent Unit Networks (GRU), along with Average Weighted Ensemble Algorithm(AWEA), Encoder-Decoder Algorithm with Attention(EDAA), and Random Forest Ensemble Algorithm(RFEA), we can achieve financial time series forecasting based on a Patched Bivariate Fréchet Copula model for dependence structures. This provides a rapid decision-making basis for preventing significant financial risks. The experimental results show that the RFEA model outperforms the other two ensemble neural network algorithms in predicting correlation structures. And also the RFEA model showed lower error (e.g., the MSE of global alpha is about 89% of the other two algorithms) and better fit (global alpha and gamma fit to 99.5% and 98.7%, respectively). It demonstrates good predictive performance and high operational efficiency, with certain application value for analyzing the correlation structure of the stock market.

关键词： Deep learning Correlation Accuracy Instruction sets Biological system modeling Predictive models Prediction algorithms Stock markets Long short term memory Autoregressive processes

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RESEARCH ON VIBRATION FATIGUE SPECTRUM METHOD OF CARBON FIBER COMPOSITE MATERIALS 30

RESEARCH ON VIBRATION FATIGUE SPECTRUM METHOD OF CARBON FIBE...

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30th International Congress on Sound and Vibration, ICSV 2024

作者： Wang, Yuzhu Kong, Deshuai Fan, Zinan Zhang, Shuang State Key Laboratory of Traction and Control System of EMU and Locomotive Beijing100081 China China Academy of Railway Sciences Locomotive & Car Research Institute Beijing Zongheng Electro-Mechanical Technology Co. Ltd. Beijing100094 China

ISBN: (纸本)9789090390581

The anisotropic properties of carbon fiber composite materials make the use of metal material vibration fatigue analysis methods in the analysis process unsuitable, especially efficient spectral analysis methods. This article presents a vibration fatigue spectrum analysis method suitable for carbon fiber composite materials by applying random excitation based on PSD spectrum and analyzing its specific fatigue life under specific PSD spectrum. And the effectiveness of this method was verified through a series of validation experiments. © 2024 Proceedings of the International Congress on Sound and Vibration. All rights reserved.

关键词： Vibration analysis

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Digital light processing three-dimensional printing with acrylic-titanium composite powders for multiscale porous scaffolds

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International Journal of Extreme Manufacturing 2025年第3期7卷 321-335页

作者： Guangbin Zhao Yanlong Wu Bochen Li Hang Tian Bo Li Xiao Li Xu Chen Tao Zhou Yaning Wang Yichao Gong Dingchang Hou Yaxiong Liu Xuewen Zong Bingheng Lu State Key Laboratory for Manufacturing System Engineering School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710054People’s Republic of China School of Mechatronic Engineering and Automation Foshan UniversityFoshan 528000People’s Republic of China Ji Hua Laboratory Foshan 528200People’s Republic of China School of Materials Science and Engineering Xi’an University of TechnologyXi’an 710048People’s Republic of China College of Mechanical Engineering Xi’an University of Science and TechnologyXi’an 710054People’s Republic of China Mechanical Engineering College Xi’an Shiyou UniversityXi’an 710065People’s Republic of China

Porous metals fabricated via three-dimensional(3D)printing have attracted extensive attention in many fields owing to their open pores and customization ***,dense internal structures produced by the powder bed fusion technique fails to meet the feature of porous materials in scenarios that demand large specific surface ***,we propose a strategy for 3D printing of titanium scaffolds featuring multiscale porous internal structures via powder modification and digital light processing(DLP).After modification,the titanium powders were composited with acrylic resin and maintained spherical *** with the raw powder slurries,the modified powder slurries exhibited higher stability and preferable curing characteristics,and the depth sensitivity of the modified powder slurries with 45 vol%solid loading increased by approximately 72%.Green scaffolds were subsequently printed from the slurries with a solid loading reaching 45 vol%via DLP 3D *** scaffolds had macropores(pore diameters of approximately 1 mm)and internal open micropores(pore diameters of approximately 5.7-13.0μm)after ***,these small-featured(approximately 320μm)scaffolds retained sufficient compressive strength((70.01±3.53)MPa)even with high porosity(approximately 73.95%).This work can facilitate the fabrication of multiscale porous metal scaffolds with high solid loading slurries,offering potential for applications requiring high specific surface area ratios.

关键词： multiscale porous metal titanium scaffolds powder modification 3D printing sintering

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Calculation of conductive ions distribution in icicle and melting water conductivity

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High Voltage 2021年第4期6卷 702-710页

作者： Yanqing Liu Lichun Shu Qin Hu Xingliang Jiang Meilin Zhu Jianbo Yu State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina State Grid Chongqing Electric Power Company ChongqingChina

The flashover problem of ice-covered insulators has seriously affected the safe operation of transmission *** researches have shown that the high conductivity water film on the surface is determined by the conductive ions distribution in the icicle which is the key factor affecting the flashover voltage of ice-covered *** our previous work,the conductive ions distribution in the icicle has been obtained through experi-ments and simulation *** order to calculate the conductivity of the water film,the conductive ion-specific content at different positions in the icicle has been calculated *** addition,based on the simulation of icicle melting process,the icicle melting process is analysed,and the melting water conductivity of the icicle is ***,melting ice test is carried out in artificial climate chamber to verify the validity of the calculation *** calculated results are in good agreement with the test *** conclusion obtained here would provide theoretical basis for establishing a flashover model of ice-covered insulators.

关键词： conductivity conductive distribution

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