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应用于交流电机驱动的新型串联绕组拓扑的动态电流控制性能分析

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中国电机工程学报 2024年第1期44卷 304-313,I0025页

作者：胡烽李安蒋栋刘自程曲荣海尹智群强电磁工程与新技术国家重点实验室(华中科技大学) 湖北省武汉市430074 数字制造装备与技术国家重点实验室(华中科技大学) 湖北省武汉市430074 广州金升阳科技有限公司广东省广州市510663

电机绕组的动态电压是影响其电流变化能力的直接因素。为了提升电机的转矩响应速度,从直流电压利用率的角度分析串联绕组拓扑的动态电流控制能力。首先,从拓扑结构出发,相比于三相半桥拓扑,串联绕组拓扑将直流电压利用率提升了73%,这使... 详细信息

电机绕组的动态电压是影响其电流变化能力的直接因素。为了提升电机的转矩响应速度,从直流电压利用率的角度分析串联绕组拓扑的动态电流控制能力。首先,从拓扑结构出发,相比于三相半桥拓扑,串联绕组拓扑将直流电压利用率提升了73%,这使得其动态电压更加充裕。然后,在不同的转速工况下,分析串联绕组拓扑、三相半桥拓扑以及采用电压修正策略的三相半桥拓扑的动态电流控制性能。最后,经仿真与实验证明,若采用电压修正策略来增大三相半桥拓扑的动态电压裕度,其只在转速接近额定转速时效果才凸显,且提升有限。而采用串联绕组拓扑,其在电压深度饱和下的电流动态响应时间将显著减小。

关键词：表贴式永磁同步电机串联绕组拓扑直流电压利用率动态响应

Unimodal productivity-biodiversity relationship along the gradient of multidimensional resources across Chinese grasslands

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National Science Review 2022年第12期9卷 90-103页

作者： Yanfen Wang Jianqing Du Zhe Pang Yali Liu Kai Xue Yann Hautier Biao Zhang Li Tang Lili Jiang Baoming Ji Xingliang Xu Jing Zhang ronghai hu Shutong Zhou Fang Wang Rongxiao Che Di Wang Chaoting Zhou Xiaoyong Cui Nico Eisenhauer Yanbin Hao Department of Medicine New York University Grossman School of Medicine Beijing Yanshan Earth Critical Zone National Research Station University of Chinese Academy of Sciences College of Life Sciences University of Chinese Academy of Sciences German Centre for Integrative Biodiversity Research (iDiv) Institute of Biology Leipzig University College of Resources and Environment University of Chinese Academy of Sciences State Key Laboratory of Tibetan Plateau Earth System Environment and Resources Chinese Academy of Sciences Beijing Yanshan Earth Critical Zone National Research Station University of Chinese Academy of Sciences School of Grassland Science Beijing Forestry University Ecology and Biodiversity Group Department of BiologyUtrecht University Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences College of Life Sciences University of Chinese Academy of Sciences School of Ecology and Environmental Sciences Yunnan University Institute of Biophysics Chinese Academy of Sciences

Resources can affect plant productivity and biodiversity simultaneously and thus are key drivers of their relationships in addition to plant-plant interactions.However,most previous studies only focused on a single resource while negle cting the nature of resource multidimensionality.Here we integrated four essential resources for plant growth into a single metric of resource diversity(RD) to investigate its effects on the productivity-biodiversity relationship(PBR) across Chinese grasslands.Results showed that habitats differing in RD have different PBRs—positive in low-resource habitats,but neutral in medium-and high-resource ones—while collectively,a weak positive PBR was observe d.However,when excluding direct effects of RD on productivity and biodiversity,the PBR in high-resource habitats became negative,which leads to a unimodal instead of a positive PBR along the RD gradient.By integrating resource effects and changing plant-plant interactions into a unified framework with the RD gradient,our work contributes to uncovering underlying me chanisms for inconsistent PBRs at large scales.

关键词： productivity–biodiversity relationship resource diversity plant strategies grassland

Quantitative Evaluation of Leaf Inclination Angle Distribution on Leaf Area Index Retrieval of Coniferous Canopies

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Journal of Remote Sensing 2021年第1期2021卷 1-15页

作者： Guangjian Yan Hailan Jiang Jinghui Luo Xihan Mu Fan Li Jianbo Qi ronghai hu Donghui Xie Guoqing Zhou State Key Laboratory of Remote Sensing Science Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Southwest China Research Institute of Electronic Equipment Chengdu 610036China Guilin University of Technology Guilin 532100China

Both leaf inclination angle distribution(LAD)and leaf area index(LAI)dominate optical remote sensing signals.The G-function,which is a function of LAD and remote sensing geometry,is often set to 0.5 in the LAI retrieval of coniferous canopies even though this assumption is only valid for spherical LAD.Large uncertainties are thus introduced.However,because numerous tiny leaves grow on conifers,it is nearly impossible to quantitatively evaluate such uncertainties in LAI retrieval.In this study,we proposed a method to characterize the possible change of G-function of coniferous canopies as well as its effect on LAI retrieval.Specifically,a Multi-Directional Imager(MDI)was developed to capture stereo images of the branches,and the needles were reconstructed.The accuracy of the inclination angles calculated from the reconstructed needles was high.Moreover,we analyzed whether a spherical distribution is a valid assumption for coniferous canopies by calculating the possible range of the G-function from the measured LADs of branches of Larch and Spruce and the true G-functions of other species from some existing inventory data and threedimensional(3D)tree models.Results show that the constant G assumption introduces large errors in LAI retrieval,which could be as large as 53%in the zenithal viewing direction used by spaceborne LiDAR.As a result,accurate LAD estimation is recommended.In the absence of such data,our results show that a viewing zenith angle between 45 and 65 degrees is a good choice,at which the errors of LAI retrieval caused by the spherical assumption will be less than 10%for coniferous canopies.

关键词： distribution function viewing

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500 kV断路器分闸异常原因分析

云南电力技术 2024年第1期52卷 43-45,61页

作者：胡发平刘荣海杨明昆云南电网有限责任公司电力科学研究院云南昆明650217

针对云南某供电局2022年初发生的一起断路器开关卡涩事故展开分析。结果显示,碳钢材质的顶杆腐蚀产生的腐蚀产物堆积是造成卡涩的主要原因,顶杆外部有镀锌防腐层,但在当地潮湿的环境中锌层容易与空气中的氧气发生电化学,并进一步导致内... 详细信息

针对云南某供电局2022年初发生的一起断路器开关卡涩事故展开分析。结果显示,碳钢材质的顶杆腐蚀产生的腐蚀产物堆积是造成卡涩的主要原因,顶杆外部有镀锌防腐层,但在当地潮湿的环境中锌层容易与空气中的氧气发生电化学,并进一步导致内部碳钢的腐蚀。为了防止此类事故,建议在潮湿的环境下顶杆采用镀铬层防护,或者直接采用不锈钢材质的顶杆。

关键词：断路器卡涩顶杆腐蚀镀层

Cloth simulation-based construction of pitfree canopy height models from airborne LiDAR data

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Forest Ecosystems 2020年第1期7卷 1-13页

作者： Wuming Zhang Shangshu Cai Xinlian Liang Jie Shao ronghai hu Sisi Yu Guangjian Yan State Key Laboratory of Remote Sensing Science Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth of Chinese Academy of SciencesBeijing Engineering Research Center for Global Land Remote Sensing ProductsInstitute of Remote Sensing Science and EngineeringFaculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Department of Remote Sensing and Photogrammetry Finnish Geospatial Research Institute02431 MasalaFinland College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China ICube Laboratory UMR 7357 CNRS-University of Strasbourg300 bd Sebastien BrantCS10413F-67412 Illkirch CedexFrance Institute of Remote Sensing and Digital Earth Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Background:The universal occurrence of randomly distributed dark holes(i.e.,data pits appearing within the tree crown)in LiDAR-derived canopy height models(CHMs)negatively affects the accuracy of extracted forest inventory parameters.Methods:We develop an algorithm based on cloth simulation for constructing a pit-free CHM.Results:The proposed algorithm effectively fills data pits of various sizes whilst preserving canopy details.Our pitfree CHMs derived from point clouds at different proportions of data pits are remarkably better than those constructed using other algorithms,as evidenced by the lowest average root mean square error(0.4981 m)between the reference CHMs and the constructed pit-free CHMs.Moreover,our pit-free CHMs show the best performance overall in terms of maximum tree height estimation(average bias=0.9674 m).Conclusion:The proposed algorithm can be adopted when working with different quality LiDAR data and shows high potential in forestry applications.

关键词： Data pits Tree crown Canopy height models Cloth simulation Pit-free

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地基激光雷达反演树木叶面积参数方法

空间科学学报 2023年第6期43卷 1160-1175页

作者：胡容海邢煜振中国科学院大学资源与环境学院北京100049 北京燕山地球关键带国家野外科学观测研究站北京101408

叶面积指数(Leaf Area Index, LAI)是表征植被冠层结构的核心参数,叶面积指数的间接测量一直是植被遥感的一项重要研究内容。地基激光雷达(Terrestrial Laser Scanning, TLS)以其高效、精细的三维观测能力被广泛用于叶面积指数的反演研... 详细信息

叶面积指数(Leaf Area Index, LAI)是表征植被冠层结构的核心参数,叶面积指数的间接测量一直是植被遥感的一项重要研究内容。地基激光雷达(Terrestrial Laser Scanning, TLS)以其高效、精细的三维观测能力被广泛用于叶面积指数的反演研究,同时地基激光雷达也为反演更精细的叶面积参数,例如叶面积体密度(Foliage Area Volume Density, FAVD)的三维分布提供了可能性。从方法论角度出发,对基于地基激光雷达反演叶面积参数的主要方法,不同方法的优势、局限性和影响因素进行分析。现有反演方法可分为四类:基于间隙率的方法、基于接触频率的方法、基于计算机图形学理论的方法以及基于生态生理学模型的方法。基于地基激光雷达的叶面积参数反演也从样方尺度叶面积指数向更精细的单木尺度叶面积垂直剖面(Vertical Foliage Profile, VFP)和体素尺度叶面积体密度发展。在此过程中,聚集效应、非均一路径长度和遮挡效应是影响测量精度的重要因素,需要进一步的研究和校正。

关键词：叶面积参数地基激光雷达间隙率接触频率体素

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小天体近距离视觉导航的陆标鲁棒匹配方法

深空探测学报（中英文） 2022年第4期9卷 407-416页

作者：胡荣海黄翔宇徐超北京控制工程研究所北京100190 空间智能控制技术重点实验室北京100190

针对目前陆标匹配方法难以应对小天体附近极端观测条件的问题,提出了一种陆标鲁棒匹配方法。对通过立体光度测量(Stereo-Photo Clinometry,SPC)法生成的地形陆标的匹配误差进行了理论分析,探讨了陆标的位置误差以及相机的位姿估计误差... 详细信息

针对目前陆标匹配方法难以应对小天体附近极端观测条件的问题,提出了一种陆标鲁棒匹配方法。对通过立体光度测量(Stereo-Photo Clinometry,SPC)法生成的地形陆标的匹配误差进行了理论分析,探讨了陆标的位置误差以及相机的位姿估计误差对匹配结果的影响;基于误差分析对陆标中的表面点进行了优化选取,并提出了加权归一化互相关(Weighted Normalized Cross-Correlation,WNCC)方法,以提高匹配精度、鲁棒性和计算效率;利用高保真度的合成图像序列对比分析了WNCC算法与目前小天体探测任务中广泛使用的归一化互相关(Normalized Cross-Correlation,NCC)算法在极端的尺度、视角和光照变化等条件下的匹配性能。数值统计结果表明,WNCC算法能够高效、鲁棒地为导航系统提供精确的陆标匹配信息。

关键词：小天体探测视觉导航陆标鲁棒匹配加权归一化互相关误差分析

Insights into the nucleation,grain growth and phase transformation behaviours of sputtered metastableβ-W films

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Journal of Materials Science & Technology 2021年第31期90卷 66-75页

作者： Shuqun Chen Jinshu Wang ronghai Wu Zheng Wang Yangzhong Li Yiwen Lu Wenyuan Zhou Peng hua Hongyi Lia Key Laboratory of Advanced Functional Materials Education Ministry of ChinaFaculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710129China High Performance Computing Department National Supercomputing Center in ShenzhenShenzhen 518055China China Ship Development and Design Center Wuhan 430074China

Metastable phase in tungsten film is of great interests in recent years due to its giant spin Hall effects,however,little information has been known on its nucleation,growth and phase transformation.In this paper,a 900 nm-thick tungsten film with double-layer structure(α-W underlayer andβ-W above it)was produced on SiO_(2)/Si substrate by high vacuum magnetron sputtering at room temperature.The structural properties ofβ-W were systemically investigated by X-ray diffraction,transmission electron microscopy,thermodynamic calculation,first-principle and phase-field simulations.It is found that theβ-W nucleation is energetically favoured on the SiO_(2)surface compared to theα-W one.As the film thickening proceeds,β-W[211]turns to be preferred direction of growth owing to the elastic strain energy minimization,which is verified by phase-field simulations.Moreover,theβ→αphase transformation takes place near the film-substrate interface while the rest of the film keeps theβ-W phase,leading to a doublelayer structure.This localized phase transition is induced by lower Gibbs free energy ofα-W phase at larger grain sizes,which can be confirmed by thermodynamic calculation.Further in-situ heating TEM analysis of the as-deposited film reveals that theβ→αphase transformation is fulfilled byα/βinterface propagation rather than local atomic rearrangements.Our findings offer valuable insights into the intrinsic properties of metastable phase in tungsten.

关键词： Metastable phases Tungsten Nucleation and growth Phase field modelling Phase transformation

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小行星动能撞击自主导航与制导方法研究

深空探测学报（中英文） 2022年第4期9卷 438-446页

作者：黄翔宇徐超胡荣海郭敏文北京控制工程研究所北京100094 空间智能控制技术重点实验室北京100094

针对近地小行星精确撞击任务需求,提出了一种小行星高精度撞击自主导航、制导与控制(Guidance Navigation&Control,GNC)方法,包括高精度的小行星中心视线提取、基于小行星中心视线测量的高精度自主相对导航及迭代预测制导。该设计利用... 详细信息

针对近地小行星精确撞击任务需求,提出了一种小行星高精度撞击自主导航、制导与控制(Guidance Navigation&Control,GNC)方法,包括高精度的小行星中心视线提取、基于小行星中心视线测量的高精度自主相对导航及迭代预测制导。该设计利用小行星中心视线测量实现了在垂直于视线方向上撞击器相对于小行星位置和速度的精确估计,在沿视线方向上撞击器相对位置和速度存在误差的情况下利用迭代预测制导实现了高精度撞击。数值仿真表明,所提出的方案能够实现50 m级近地小行星4 m级撞击精度,满足了任务要求。

关键词：小行星防御动能撞击 GNC 自主导航