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Type Synthesis of Fully-isotropic 2T3R 5-DoF Hybrid Mechanisms

Journal of the Chinese Society of Mechanical Engineers, Transactions of the Chinese Institute of Engineers, Series C/Chung-Kuo Chi Hsueh Kung Ch'eng Hsuebo Pao 2019年第3期40卷 307-314页

作者： Zhang, Hong Zhou, Hui Qin, Youlei Ge, Shuyi Wang, Kun Cao, Yi School of Mechanical Engineering Jiangnan University Wuxi214122 China State Key Laboratory of Mechanical System and Vibration Shanghai200240 China State Key Laboratory of Robotics and System Harbin150080 China Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology Wuxi214122 China

In mechanical design, it is necessary to synthesize the mechanism,especially for the fully-isotropic hybrid mechanisms (HMs). This article proposes a simple but very effective approach for fully-isotropic HMs by means of GF set theory. firstly, a type synthesis method for HMs is simply presented, especially, the option standard of the input motion joint and the steps for the integration of the branches are given which provide the theoretical foundations for the integration of the type structure of completely isotropic HMs. Secondly, the process of type synthesis for fully-isotropic HMs is described in detail. To corroborate the usefulness of the proposed method for fully-isotropic HMs, type synthesis of fully-isotropic 2T3R 5-Degree-0f-Freedom (DoF) HMs is illustrated with example, where T denotes translation and R denotes rotation. Finally, the forward displacement analysis of a synthesized 2T3R fully-isotropic HM is carried out. The expression of the Jacobian matrix is deduced, it shows that the Jacobian matrix of the synthesized fully-isotropic HM is a 5×5 identity matrix throughout the entire workspace validating the fully-isotropic feature of the HM and the effectiveness of the type of composite approach for fully-isotropic HMs. © 2019, Chinese Mechanical Engineering Society. All right reserved.

关键词： Jacobian matrices

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Impact of Electric Vehicles Access to Distribution Network under V2G Mode

Impact of Electric Vehicles Access to Distribution Network u...

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IEEE International Conference on Smart Grid and Smart Cities (ICSGSC)

作者： Gang Lu Guangru Zhang Jiawu Zhang Zhenqi Ma Xinglong Li Yongqiang Kang School of New Energy and Power Engineering Lanzhou Jiaotong University Lanzhou China State Grid Gansu Electric Power Research Institute Lanzhou China Key Laboratory of Large Electric Drive System and Equipment Technology Tianshui China

Established the electric vehicles charging load demand model and the electric vehicles response discharge model under vehicle-to-grid (V2G) mode. The IEEE33-bus distribution system is selected for simulation, and Monte Carlo simulation is used to simulate the impact of electric vehicles charging and discharging on distribution network loss and node voltage. The results indicate that reasonable charging and discharging of electric vehicles under V2G mode can effectively improve the impact of electric vehicles access to distribution network.

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Measurement and Modeling of Vehicular Millimeter Wave Radar Signal in Expressway Environment

Measurement and Modeling of Vehicular Millimeter Wave Radar ...

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European Conference on Antennas and Propagation, EuCAP

作者： Hongyu Duan Danping He Ke Guan Zhangdui Zhong Yihua Ma State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China Beijing Engineering Research Center of High-Speed Railway Broadband Mobile Communications Beijing China Frontiers Science Center for Smart High-speed Railway System Beijing China Key Laboratory of Railway Industry of Broadband Mobile Information Communications Beijing China State Key Laboratory of Mobile Network and Mobile Multimedia Technology Shenzhen China ZTE Corporation Shenzhen China

With the gradual development of autonomous driving technology, the cost of traditional road test is becoming higher and higher. The mainstream approach of autonomous driving test has been transferred to the accurate and efficient simulation test system based on typical environment. Millimeter wave (mmWave) radar is an important part of autonomous driving and integrated sensor system. This means that the foundation of the future autonomous driving environment simulation system needs the real mmWave vehicular radar signal propagation mechanism. Therefore, the research of radio wave propagation characteristics in vehicular mmWave radar frequency band is the basis of mmWave radar simulation. In this paper, the vehicular mmWave radar signal in the expressway environment is measured, and ray-tracing (RT) simulation is conducted according to the measurement configuration. The electromagnetic (EM) parameters is calibrated through the Radar Cross section (RCS). The signal propagation characteristics are researched, and a hybrid channel model is established with RT, which effectively increases the simulation efficiency and serves for future autonomous vehicle driving test.

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Control and simulation analysis of 120kW charging pile

Control and simulation analysis of 120kW charging pile

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12th IET International Conference on Advances in Power system Control, Operation and Management (APSCOM 2022)

作者： Y. An Z. Cheng H. Li S. Zhu J. Liu Z. Wei X. Du Shenzhen Power Supply Bureau Co. Ltd Shenzhen China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing China

In recent years, with the continuous promotion and accelerated utilization of renewable energy, the electric vehicle industry presents a rapid development trend. As an indispensable link in the field of electric vehicles, the number of charging piles is also rising. However, the power grid is affected seriously for connecting into the excessive number of charging piles. Therefore, this paper focuses on the control and simulation analysis of the mainstream 120kW DC charging piles in the market. Firstly, the DC charging pile topology is analyzed. Secondly, the control strategy and main circuit design of each part are analyzed. Base on above study, a three-stage charging control is designed to control the charging piles of electric vehicles. Farther, a simulation model of the DC charging pile is developed based on the PSCAD/EMTDC. On this basis, the effects of the number of charging piles, charging power and initial battery charge state are analyzed for studying key influencing factors on the grid harmonics. This paper provides a research basis for analyzing the advantages and benefits of charging piles with PV energy storage. In addition, this model can also be used to analyze the power quality of large-scale power stations connected to distribution networks.

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All operating conditions simulation model of distributed photovoltaic power station based on PSCAD

All operating conditions simulation model of distributed pho...

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12th IET International Conference on Advances in Power system Control, Operation and Management (APSCOM 2022)

作者： H. Xie L. Fan Y. An Z. Wei J. Liu X. Du Shenzhen Power Supply Bureau Co. Ltd Shenzhen China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing China

The newly installed scale of distributed photovoltaic is far larger than that of centralized photovoltaic, so the related research work of distributed photovoltaic has attracted a wide spread attention. However, the existing simulation model of distributed photovoltaic power station only focuses on single operating condition, which cannot meet the requirements of simulation and the analysis of distributed photovoltaic power station at all operating conditions. In order to overcome the above defects, this paper presents a simulation model under all operating conditions based on the PSCAD/EMTDC. Meanwhile it can provide a model basis for studying the stability and control problems of distributed photovoltaic power station under different operating conditions. Firstly, photovoltaic array is established according to engineering mathematical model. Secondly, the control strategies under different working conditions are studied, and the photovoltaic inverter model with all operating conditions control strategy is established. Thirdly, distributed photovoltaic power station is built by current-doubler ***, three scenarios are simulated to verify the output characteristic under different operating *** simulation results show that all operating conditions simulation model of distributed photovoltaic power station based on PSCAD can achieve the expected operation effect.

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An Improved BCTRAN Model of Three-phase Three-limbs Transformer in Offshore Wind Power systems

An Improved BCTRAN Model of Three-phase Three-limbs Transfor...

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International Conference on High Voltage Engineering and Application, ICHVE

作者： Ke Wang Yang Long Gang Li Wenxia Sima Ming Yang China Electric Power Research Institute Beijing China State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing University Chongqing China

ISBN: (数字)9781665407502

ISBN: (纸本)9781665407519

With the rapid development of clean energy,three-phase three-limb transformer is widely used in offshore wind power systems. However, the classical BCTRAN model can not accurately simulate the deep saturation phenomenon at each terminal. In this paper the improved BCTRAN model of three-phase three-limbs transformer has been built. The improved BCTRAN matrix of three-phase three-limbs transformer can accurately describe the coupling relationship between different windings. Deep saturation inductances are measured and determined using the hybrid source method to create the magnetizing branch, including the deep saturation region. Inrush current experiments on a 12.5MVA three-phase three-limb transformer in offshore wind power systems show that the first peak error of inrush current of the improved BCTRAN model is reduced from 24.9% to -1.7 % , comparing with the traditional model, whichcan accurately represent the saturation characteristics and provide a basic model for hree-phase three-limb transformers in offshore wind power systems

关键词： Couplings Current measurement Windings High-voltage techniques Wind power generation Finite element analysis Circuit faults

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Application of Cu-Graphene(Porous)-Agnps for Quantitative Sers Detection of Transformer Oil-Paper Insulation Aging Characteristics

SSRN

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SSRN 2024年

作者： Yang, Dingkun Lei, Yu Fan, Zhou Chen, Weigen Wan, Fu Chongqing University of Posts and Telecommunication Chongqing China State Grid Gansu Electric Power Company Wuwei Power Supply Company China State Grid Jiangsu Electric Power Consulting Engineering Co. Ltd China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China Chongqing University China

Surface-enhanced Raman scattering (SERS) has emerged as a highly sensitive trace detection tool, becoming a popular analytical technique widely applied in various fields such as electrical engineering. This paper focuses on the application of surface-enhanced technology for the quantitative detection of aging characteristics in transformer oil-paper insulation. Ag nanoparticles (AgNPs) were deposited on porous graphene-coated Cu foil to prepare a Cu-Graphene (porous)-AgNPs surface-enhanced substrate, which prevents the oxidation of nanoparticles while maintaining SERS activity. The adsorption capacity of the substrate for small organic molecules such as furfural was improved by creating holes in the graphene, and the size of Ag nanoparticles was optimized to achieve better detection results. The performance of the substrate was tested using R6G as a probe molecule, and the results demonstrated that the substrate has good sensitivity, uniformity, and anti-oxidation properties. When the substrate was used for the detection of transformer aging characteristics, the detection limits for furfural, acetone, and methanol reached 0.04 mg/L, 0.18 mg/L, and 0.18 mg/L, respectively, meeting the analytical requirements for oil-immersed transformers. This research has significant implications for ensuring the stability of power supply systems and the steady development of the national economy. © 2024, The Authors. All rights reserved.

关键词： Furfural

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Uplink Performance of Cell-Free Extremely Large-Scale MIMO systems

arXiv

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arXiv 2023年

作者： Lei, Hao Wang, Zhe Xiao, Huahua Zhang, Jiayi Ai, Bo School of Electronic and Information Engineering Beijing Jiaotong University Beijing100044 China Frontiers Science Center for Smart High-speed Railway System Beijing Jiaotong University Beijing100044 China ZTE Corporation State Key Laboratory of Mobile Network and Mobile Multimedia Technology State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing100044 China

In this paper, we investigate the uplink performance of cell-free (CF) extremely large-scale multiple-input-multiple-output (XL-MIMO) systems, which is a promising technique for future wireless communications. More specifically, we consider the practical scenario with multiple base stations (BSs) and multiple user equipments (UEs). To this end, we derive exact achievable spectral efficiency (SE) expressions for any combining scheme. It is worth noting that we derive the closed-form SE expressions for the CF XL-MIMO with maximum ratio (MR) combining. Numerical results show that the SE performance of the CF XL-MIMO can be hugely improved compared with the small-cell XL-MIMO. It is interesting that a smaller antenna spacing leads to a higher correlation level among patch antennas. Finally, we prove that increasing the number of UE antennas may decrease the SE performance with MR combining. Copyright © 2023, The Authors. All rights reserved.

关键词： MIMO systems

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Intelligent design of mechanical metamaterials: a GCNN-based structural genome database approach

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National Science Review 2025年第4期 268-281页

作者： Wenyu Hao Zongliang Du Xiuquan Hou Yilin Guo Chang Liu Weisheng Zhang Huajian Gao Xu Guo State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDepartment of Engineering Mechanics Dalian University of Technology Ningbo Institute of Dalian University of Technology Institute of Artificial Intelligence and Robotics Xi'an Jiaotong University Mechano-X Institute Applied Mechanics LaboratoryDepartment of Engineering Mechanics Tsinghua University

The reciprocal mapping between the geometry and properties of a unit cell is crucial for the intelligent and inverse design of advanced materials and structural *** classical homogenization-based numerical methods,this paper presents an efficient and accurate mapping between the geometry and properties of a class of unit cells described by moving morphable components,achieved via a graph convolutional neural *** leads to a structural genome database(SGD) approach for the intelligent design of mechanical *** the SGD approach,metamaterials exhibiting the Hashin-Shtrikman upper bound of bulk modulus,auxetic behavior and the unimodal property have been created,with design efficiency improved by 3-4 orders of ***,transfer learning and a small amount of training data allow the SGD to predict non-local behaviors beyond a unit cell,such as optimized unit cells with critical buckling strength enhanced by nearly 200% and a bandgap metamaterial with a relative bandgap width of 51%.Experimentally validated optimized metamaterials demonstrate auxetic behavior and superior buckling *** proposed SGD approach holds promise for the advanced design of multi-scale and multi-physics systems.

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Comparing the climate change mitigation potentials of alternative land uses:Crops for biofuels or biochar *** regrowth

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Geography and Sustainability 2022年第4期3卷 347-357页

作者： Anne Cecilie Løvenskiold Xiangping Hu Wenwu Zhao Francesco Cherubini Department of Energy and Process Engineering Industrial Ecology ProgrammeNorwegian University of Science and Technology(NTNU)TrondheimNorway State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Institute of Land Surface System and Sustainable Development Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China

Using biomass from dedicated crops for energy production and natural vegetation regrowth are key elements in future climate change mitigation ***,there are still uncertainties about the mitigation potentials that can be achieved by the different land-based systems and how they perform relative to each *** this study,we use harmonized future land use datasets to identify global land areas dedicated to second generation bioenergy crop production in 2050 under different climate *** then assess the global climate change mitigation potentials of using biomass for producing bioethanol with(BECCS)or without carbon capture and storage,biochar,or a synthetic fuel(e-methanol).For the latter,the electricity required to produce hydrogen for e-methanol synthesis is sourced from either wind power or the projected average electricity mix in *** potential from natural regrowth on the identified land is also *** all the cases,we modelled emissions of greenhouse gases from the life-cycle stages and use parameterized models to estimate local biomass growth *** identified land areas range from 1.95 to 13.8 million hectares and can provide from 30 to 178 mega ton(Mt)dry biomass annually from dedicated *** change mitigation potentials range from 11 to 257 MtCO_(2)-***^(−1),depending on technological option and land *** largest mitigation is delivered by BECCS,but e-methanol can achieve similar findings when hydrogen is sourced from wind *** hydrogen is produced from grid electricity,e-methanol can result in net positive emissions.E-methanol can also deliver more final energy than bioethanol(4.04 vs.1.27 EJ yr^(−1)).Natural vegetation regrowth can generally achieve higher mitigation than bioethanol,but less than *** optimal combination of BECCS and natural vegetation regrowth can achieve a larger mitigation,up to 281 MtCO_(2)-***^(−1),indicating that integrated solutions can help to achieve suc

关键词： Negative emission technologies Natural regrowth Land management Bioenergy systems Carbon neutrality

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