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一种抑制模块化多电平变换器光伏系统共模电压的脉冲衔尾排布调制

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电工技术学报 2025年第4期40卷 1221-1235页

作者：潘尧孙孝峰蔡瑶李昕赵巍燕山大学电力电子节能与传动控制河北省重点实验室秦皇岛066004

光伏模块利用模块化的特点,可以分布集成在模块化多电平变换器子模块的直流侧,构成基于模块化多电平变换器的光伏系统(MMC-PVS)。由阴影遮挡、损坏等问题引起的光伏模块功率不平衡会使子模块的调制信号存在显著差异,严重降低现有共模电... 详细信息

光伏模块利用模块化的特点,可以分布集成在模块化多电平变换器子模块的直流侧,构成基于模块化多电平变换器的光伏系统(MMC-PVS)。由阴影遮挡、损坏等问题引起的光伏模块功率不平衡会使子模块的调制信号存在显著差异,严重降低现有共模电压抑制方案的抑制效果。为了解决这些问题,该文提出一种脉冲衔尾排布调制,能够在光伏模块功率不平衡工况下抑制MMC-PVS的共模电压。通过分析光伏模块功率不平衡工况下MMC-PVS,实现零共模电压的条件,表明理论上子模块的调制信号具备实现零共模电压的能力,而由调制策略生成的子模块驱动脉冲是产生共模电压的关键因素。脉冲衔尾排布调制能将子模块驱动脉冲依次衔尾排布,即后一子模块的上升沿时刻与前一子模块的下降沿时刻对齐,在每个开关周期内保证三相上桥臂总电压与三相下桥臂总电压的形状相同,达到理论上零共模电压的效果,实现共模电压抑制。最后,通过仿真与实验验证了脉冲衔尾排布调制在光伏模块功率不平衡工况下抑制共模电压的可行性与理论分析的正确性。

关键词：模块化多电平变换器光伏系统光伏功率不平衡共模电压脉冲衔尾排布调制

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挠性陀螺交叉耦合影响因素分析及控制

北京航空航天大学学报 2025年第1期51卷 141-151页

作者：蔡曜司玉辉王玉琢杜鑫尹路西安航天精密机电研究所西安710100

由于机械结构误差和电气干扰,实际生产的挠性陀螺存在交叉耦合。分析交叉耦合影响因素,确定其为差动式电感传感器铁芯柱垂直度和力矩器线圈周向偏移角度,由此建立传感器、力矩器的误差模型,定量分析了各影响因素对交叉耦合的影响程度。... 详细信息

由于机械结构误差和电气干扰,实际生产的挠性陀螺存在交叉耦合。分析交叉耦合影响因素,确定其为差动式电感传感器铁芯柱垂直度和力矩器线圈周向偏移角度,由此建立传感器、力矩器的误差模型,定量分析了各影响因素对交叉耦合的影响程度。设计铁芯柱精密装配工装、线圈精密装配工装,并对力矩器进行可调设计,控制挠性陀螺交叉耦合。工程实践表明:各项控制方法均取得较好效果,交叉耦合稳定控制为不大于1%;各项控制方法提高了挠性陀螺对角速度的测量精度,进而提高了惯导系统的导航精度。

关键词：挠性陀螺交叉耦合影响因素差动式电感传感器力矩器可调设计

Deep hybrid: Multi-graph neural network collaboration for hyperspectral image classification

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Defence Technology（防务技术） 2023年第5期23卷 164-176页

作者： Ding yao Zhang Zhi-li Zhao Xiao-feng cai Wei He Fang cai yao-ming Wei-Wei cai Xi'an Research Institute of High Technology Xi'an710025China The School of Computer Science China University of GeosciencesWuhan430074China The School of Artificial Intelligence and Computer Science Jiangnan UniversityWuxi214122China

With limited number of labeled samples,hyperspectral image(HSI)classification is a difficult Problem in current *** graph neural network(GNN)has emerged as an approach to semi-supervised classification,and the application of GNN to hyperspectral images has attracted much ***,in the existing GNN-based methods a single graph neural network or graph filter is mainly used to extract HSI features,which does not take full advantage of various graph neural networks(graph filters).Moreover,the traditional GNNs have the problem of *** alleviate these shortcomings,we introduce a deep hybrid multi-graph neural network(DHMG),where two different graph filters,i.e.,the spectral filter and the autoregressive moving average(ARMA)filter,are utilized in two *** former can well extract the spectral features of the nodes,and the latter has a good suppression effect on graph *** network realizes information interaction between the two branches and takes good advantage of different graph *** addition,to address the problem of oversmoothing,a dense network is proposed,where the local graph features are *** dense structure satisfies the needs of different classification targets presenting different ***,we introduce a GraphSAGEbased network to refine the graph features produced by the deep hybrid *** experiments on three public HSI datasets strongly demonstrate that the DHMG dramatically outperforms the state-ofthe-art models.

关键词： Graph neural network Hyperspectral image classification Deep hybrid network

Limits of Uneven Battery Power in Modular Multilevel Converter-based Battery Energy Storage Systems

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 686-695页

作者： yao Pan Xiaofeng Sun Wei Zhao Xin Li yao cai Institute of Electrical Engineering Yanshan UniversityQinhuangdao 066004China

For modular multilevel converter-based battery energy storage systems (MMC-BESS), uneven power among batteries of SMs will be deduced by battery aging, battery fault, etc., which will degrade performance and even lead to system failure. For maintaining the balance of capacitor voltage, this paper analyzes the limits of the uneven power of batteries, which are presented as the current limits in this paper. According to analysis, an analytical method is proposed that only the dc and fundamental frequency components of the arm current are used to calculate current limits. With the current limits it is able to evaluate the reasonability of power distribution among batteries. Meanwhile, increase of fundamental frequency component will enhance the current limits, and the dc component determines the size relationship between the absolute values of the upper and lower current limits. Finally, simulation model and experiment prototype are built for verifying the theoretical analysis and current limits calculation method, and satisfactory results are provided.

关键词： Arm current balance of capacitor voltage current limits MMC-BESS uneven power

L^q Interior Estimates of the Gradient for Weak Solutions of Quasilinear Elliptic Equations

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Acta Mathematica Sinica,English Series 2007年第12期23卷 2225-2234页

作者： Feng Ping yao Yong Yong cai LMAM School of Mathematical Sciences Peking University Bering 100871 P. R. China

The authors present a new proof of L^q interior estimates of the gradient for weak solutions of a quasilinear elliptic equation of p-Laplacian type.

关键词： L^q interior estimates weak solutions quasilinear elliptic maximal function

Control of a Spherical Robot: Path Following Based on Nonholonomic Kinematics and Dynamics

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Chinese Journal of Aeronautics 2011年第3期24卷 337-345页

作者： ZHENG Minghui ZHAN Qiang LIU Jinkun cai yao Robotics Institute Beihang University Beijing 100191 China School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China

This paper presents the controller design for the path following of a spherical mobile robot, BHQ-1. Firstly, a desired velocity for the reference path is deduced from the kinematic model, which cannot be transformed into the classic chained form. Secondly, a necessary torque for the desired velocity is obtained based on the dynamic model. As to the kinematics, a one-dimensional function is selected to measure the two-directional tracking error, and the velocity of rolling forward is reasonably assumed to be constant; therefore the multiple-input multiple-output （MIMO） system is transformed into a single-input single-output （SISO） system. As to the dynamics, both exact dynamics and inexact dynamics with modeling error as well as bounded unknown disturbance are taken into account, based on which a proportional-derivative （PD） controller and a sliding mode controller with adaptive parameters are proposed respectively. Finally, convergence analysis and simulation results are provided to validate these controllers.

关键词： spherical robot path following nonholonomic kinematics dynamics

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灌区斗口测流设备自动除泥沙装置研究

中国农村水利水电 2025年第1期 144-148页

作者：张欣张健翟林鹏梁妙元姚文才南京津码智能科技有限公司江苏南京210046 江苏省农村水利科技发展中心江苏南京210029

我国西北地区年均降雨量小于400 mm,属于常年灌水区,没有灌溉就没有稳定的产量。其中从引黄灌区引入的水泥沙含量较高,在流速偏低的支渠和斗渠等,会形成泥沙堆积。当泥沙在渠道布设的测流设备和闸门测控系统中堆积到一定程度后,严重影... 详细信息

我国西北地区年均降雨量小于400 mm,属于常年灌水区,没有灌溉就没有稳定的产量。其中从引黄灌区引入的水泥沙含量较高,在流速偏低的支渠和斗渠等,会形成泥沙堆积。当泥沙在渠道布设的测流设备和闸门测控系统中堆积到一定程度后,严重影响测流精度和闸门开度的感知。为了解决智慧灌区中对高泥沙含量水质测流设备的有效运用,提高小型渠道流量的精准测量,研究设计了一种超声波振动单元,可安放在斗口测流系统和测控一体化闸门中。该振动单元包括密封盒、金属盖板和线路板,密封盒设有一个顶口,金属盖板盖在密封盒的顶口上,线路板上设有信号接口电路、电源模块、延迟电路、PWM(脉冲宽度调制:Pulse Width Modulation)控制芯片、MOS管电路、漏电保护芯片、变压器电路、匹配电路和超声波换能器。振动单元工作时长和工作间隔受延时芯片控制,可通过控制接口的信号配置,MOSFET晶体管开合由PWM控制芯片控制,超声波频率由PWM频率控制。振动单元的控制集成在测流系统中,由该系统根据现场情况给出控制指令,分为固定和动态两种。该装置可根据泥沙堆积情况,自动开启振动清除堆积泥沙。样机在试验室中进行了实验,得到不同程度泥沙堆积情况下振动除沙的结果,验证了清除堆积泥沙的有效振动时长,并在宁夏现场进行了试用。试验结果表明,随着泥沙累积量的增加,超声波振动时长也会增加,在淤积厚度不超过30 mm时,启动超声波振动装置工作一次(3 min)就能有效清除淤积。

关键词：测流设备自动除积智慧灌区超声波振动单元

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Importance of microhabitat selection by birds for the early recruitment of endangered trees in a fragmented forest

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Avian Research 2020年第4期11卷 446-451页

作者： Ning Li Zheng Wang yao cai Lin Zhang Institute of Applied Ecology Nanjing Xiaozhuang UniversityNanjing 211171JiangsuChina College of Biology and Environmental Science Nanjing Forestry UniversityNanjing 210037China Hangzhou Key Laboratory for Animal Adaptation and Evolution College of Life and Environmental SciencesHangzhou Normal UniversityHangzhou 311121China

Background:Remnant microhabitats are important for bird habitat selection and plant regeneration in the fragmented ***,empirical information on the consequences of how microhabitat use by birds affects the early recruitment of plants is ***:In this study,we evaluated whether microhabitat selection by the Black Bulbul(Hypsipetes leucocephalus)(***,1789)impacts the early recruitment of the endangered tree species,the Chinese Yew(Taxus chinensis(Pilger)Rehd),in a fragmented forest over a 4-year period(2011–2012,2018–2019).Results:Our results showed the main factors affecting *** microhabitat selection were distance to the nearest *** mature tree,herb cover and density,leaf litter cover,and vegetation ***,the results of logistic regression also highlighted the importance of elevation,distance to light gap and roads,tree cover in bird microhabitat ***,the seed emergence rate in microhabitats used by birds did not differ from the natural forest,which was related to five factors of bird *** Random Forest model showed that seedling emergence rate was increased with leaf litter cover and distance to fallen dead trees,but decreased in relation to herb cover,slope,and ***:Our results highlight the importance of remnant microhabitats in fragmented forests for sustaining forest ecology and optimal *** contribution of microhabitats used by birds to plant recruitment provides insights into how frugivore species contribute to plant regeneration,which should be incorporated in future conservation and management practices of fragmented forests.

关键词： Fragmented forest Hypsipetes leucocephalus Microhabitat use Seedling recruitment Taxus chinensis

Syntheses and Crystal Structures of Two New One-dimensional Double Hydrogen-bonding-chain Complexes [Ni(bipy)_2Cl]·ClO_4 and [Zn(bipy)_2Cl]·BF_4

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Chinese Journal of Structural Chemistry 2007年第5期26卷 541-546页

作者： yao Jing-cai yao Feng-Juan GUO Jin-Bo HUANG Wei GOU Shao-Hua Department of Chemistry Luoyang Normal University Luoyang Henan 471022 China Coordination Chemistry Institute State Key Laboratory of Coordination Chemistry Nanjing University Nanjing Jiangsu 210093 China

Two new transition metal complexes, [Ni（bipy）2Cl]·ClO4 （bipy = 2,2＇-bipyridine） 1 and [Zn（bipy）2Cl]·BF4 2, have been synthesized and characterized by single-crystal X-ray diffraction analysis. Both 1 and 2 crystallize in monoclinic space group P21/n with Z = 4. For 1, a = 10.776（1）, b = 12.067（1）, c = 16.146（2）A, β = 93.021（2）o, V = 2031.9（4） A^3, Mr = 505.98, Dc = 1.654 g/cm^3, μ = 1.255 mm^–1, F（000） = 1032, the final R = 0.0406 and wR = 0.1002 for 3983 observed reflections with Ⅰ 〉 2σ（Ⅰ）. For 2, a = 10.758（4）, b = 12.058（4）, c = 16.135（5） A, β = 104.57（1）o, V = 2025.7（12） A^3, Mr = 500.00, Dc = 1.639 g/cm^3, μ = 1.396 mm^–1, F（000） = 1008, the final R = 0.0470 and wR = 0.1237 for 3759 observed reflections with Ⅰ 〉 2σ（Ⅰ）. The crystal structures of 1 and 2 are isostructural with very similar supramolecular structures. A one-dimen-sional zigzag double hydrogen-bonding-chain is generated by the intermolecular M-bipy ···anion···bipy- M hydrogen bonding interactions between the chelating ligands of bipy and anion.

关键词： double hydrogen-bonding-chain 2,2'-bipyridine transition metal