检索结果-南通市图书馆

Journal of Modern Power Systems and Clean Energy 2022年第3期10卷 678-688页

作者： Zhongwen Li Zhiping Cheng jikai si Shuhui Li School of Electrical Engineering Zhengzhou UniversityZhengzhou 450001China Department of Electrical and Computer Engineering The University of AlabamaTuscaloosaAL 35487USA

This paper proposes a novel distributed event-triggered secondary control method to overcome the drawbacks of primary control for direct current(DC)microgrids.With eventtriggered distributed communication,the proposed control method can achieve system-wide control of parallel distrubted generators(DGs)with two main control objectives:①estimate the average bus voltage and regulate it at the nominal value;②achieve accurate current sharing among the DGs in proportion to their power output ratings.Furthermore,the proposed control strategy can be implemented in a distributed way that shares the required tasks among the DGs.Thus,it shows the advantages of being flexible and scalable.Furthermore,this paper proposes a simple event-triggered condition that does not need extra state estimator.Thus,limited communication among neighbors is required only when the event-triggered condition is satisfied,which significantly reduces the communication burden at the cyber layer.

关键词： Direct current(DC)microgrid droop control event-triggered secondary control distributed consensus load sharing

The Characteristics Analysis and Cogging Torque Optimization of a Surface-Interior Permanent Magnet Synchronous Motor

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electrical Engineering 2018年第4期4卷 41-47页

作者： jikai si Suzhen Zhao Lufeng Zhang Ruiwu Cao Wenping Cao College of Electric Engineering Zhengzhou UniversityZhengzhou 450000China School of Electrical Engineering and Automation Henan Polytechnic UniversityJiaozuo 454003China School of Automation Nanjing University of Aeronautics and AstronauticsNanjing 211106China School of Engineering and Applied Science Aston University Birmingham B47ETUK

This paper proposes optimal stator skewed slot analytical method for cogging torque reduction in surface-interior permanent magnet synchronous motor(siPMSM)and analyzes the characteristics of siPMSM.The series-parallel equivalent magnetic circuit models(EMCMs)of siPMSM is built based on the characteristics of magnetic circuits,which is used to design the basic electromagnetic parameters of siPMSM.Analytical expressions of cogging torque are derived from applying analytical techniques.Stator skewed slot for cogging torque minimum is adopted,and the stator skewed slot pitch is confirmed based on the analytical expressions of the resultant cogging torque.The cogging torque,torque ripple,back electromotive force(back-EMF),power-angle characteristics,efficiency and power factor of siPMSM are analyzed by establishing 3-dimensional finite element model(3-D-FED)of siPMSM with stator skewed slot and straight slot.It is shown that the comprehensive performance of optimized siPMSM is improved as confirmed by finite element analysis and analytical calculation results.

关键词： Surface-interior permanent magnet synchronous motor(siPMSM) cogging torque stator skewed slot three-dimensional finite element model(3-D-FED)

Multi-Objective Optimization of Surface-Mounted and Interior Permanent Magnet Synchronous Motor Based on Taguchi Method and Response Surface Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electrical Engineering 2018年第1期4卷 67-73页

作者： jikai si Suzhen Zhao Haichao Feng Ruiwu Cao Yihua Hu School of Electrical Engineering and Automation Henan Polytechnic UniversityJiaozuo 454003China School of Automation Nanjing University of Aeronautics and AstronauticsNanjing 211106China Department of Electrical Engineering and Electronics University of LiverpoolLiverpoolUK

The surface-mounted and interior permanent magnet synchronous motor(siPMSM)has the characteristics of multiple variables,strong coupling and nonlinearity.In order to improve the performance of siPMSM,this paper presents a multi-objective optimal design process using Taguchi and response surface methodology(RSM).The peak value of cogging torque(PVCT),ratio value of average torque and permanent magnet weight(RTW),torque ripple and back-EMF total harmonics distortion(ETHD)are selected as optimization goals.The experiment matrix is established by Taguchi method,and analyzed the tendency and proportion of the effect of the optimization parameters on siPMSM performance.The rules of choosing multi-objective optimization parameters are obtained.The least-squares method is used to establish the optimal objective function,and RSM is used to obtain the resolutions of the optimization objective function.Comparing the initial performance with optimized performance verifies the effectiveness of the proposed method.

关键词： Surface-mounted and interior permanent magnet synchronous motor(siPMSM) multi-objective optimization Taguchi response surface methodology(RSM) least-square method

Analysis of temperature field for a surface-mounted and interior permanent magnet synchronous motor adopting magnetic-thermal coupling method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CES Transactions on Electrical Machines and Systems 2018年第1期2卷 166-174页

作者： jikai si Suzhen Zhao Haichao Feng Yihua Hu Wenping Cao School of Electrical Engineering and Automation Henan Polytechnic UniversityJiaozuoChina Department of Electrical Engineering and Electronics University of LiverpoolLiverpoolUK School of Electronics Electrical Engineering and Computer ScienceQueen’s University BelfastdNorthern IrelandUK

Aiming at obtaining high power density of surface-mounted and interior permanent magnet synchronous motor(siPMSM),it is important to accurately calculate the temperature field distribution of siPMSM,and a magnetic-thermal coupling method is proposed.The magnetic-thermal coupling mechanism is analyzed.The thermal network model and finite element model are built by this method,respectively.The effects of power frequency on iron losses and temperature fields are analyzed by the magnetic-thermal coupling finite element model under the condition of rated load,and the relationship between the load and temperature field is researched under the condition of the synchronous speed.In addition,the equivalent thermal network model is used to verify the magnetic-thermal coupling method.Then the temperatures of various nodes are obtained.The results show that there are advantages in both computational efficiency and accuracy for the proposed coupling method,which can be applied to other permanent magnet motors with complex structures.

关键词： Equivalent thermal network method magnetic-thermal coupling method power frequency iron loss surface-mounted and interior permanent magnet synchronous motor(siPMSM) temperature field

Effect of biochar application on rice,wheat,and corn seedlings in hydroponic culture

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第1期135卷 379-390页

作者： Yingjie Yin jikai Li sihang Zhu Qing Chen Chong Chen Yukui Rui Jianying Shang College of Land Science and Technology China Agricultural UniversityKey Laboratory of Plant-Soil InteractionsMinistry of Educationand Key Laboratory of Arable Land Conservation in North ChinaMinistry of Agriculture and Rural AffairsBeijing 100193China Agricultural Management Institute Ministry of Agriculture and Rural AffairsBeijing 102208China College of Resources and Environmental Sciences China Agricultural UniversityBeijing Key Laboratory of Farmland Soil Pollution Prevention and RemediationBeijing 100193China

In recent years,biochar has attracted considerable attention for soil quality improvement and carbon sequestration due to its unique physicochemical properties.However,the mechanism by which biochar application negatively affects the growth of crop seedlings has not been fully investigated.In this study,a hydroponic experiment was conducted to evaluate the response of rice,wheat,and corn seedlings to biochar application(CK,0 g/L;BC1,0.5 g/L;and BC2,1.0 g/L).Compared with the CK treatment,the BC1 and BC2 treatments decreased the fresh shoot and root weights of rice and corn seedlings(Psignificant effect on wheat seedlings(P>0.05).For the contents of nutrient elements in seedlings,both BC1 and BC2 treatments hindered the roots from absorbing Fe and Cu and increased the uptake of Ca and Mn.Compared with the CK treatment,the translocation factor(TF)values of Ca,Mn,and Zn were significantly decreased especially in rice seedlings(35.3%-36.8%,68.7%-76.5%,and 29.8%-22.0%,respectively)under the BC1 and BC2 treatments,while only Mn was significantly decreased in wheat and corn seedlings(Psion electron microscope(TEM)analysis of root cross-sections showed that nano-sized biochar particles(10~23 nm)were found in the root cells under BC2 treatment conditions.Our findings reveal that a large amount of biochar application can reduce nutrient absorption and translocation,and hinder rice,wheat,and corn seedlings,particularly rice seedling,in hydroponic system.

关键词： Biochar Toxicity Seedling growth Hydroponic cultivation

基于线圈子单元的永磁同步电机健康与定子绕组短路故障数学模型

在线全文

学校读者我要写书评

暂无评论

电工技术学报 2023年第4期38卷 957-969页

作者：高彩霞苗壮陈昊司纪凯吕珂河南理工大学电气工程与自动化学院焦作454003 河南理工大学应急管理学院焦作454003 郑州大学电气工程学院郑州450001 海军工程大学舰船综合电力技术国防科技重点实验室武汉430033

针对相绕组为基本单元的永磁同步电机定子绕组短路故障数学模型,存在故障空间位置影响无法计及、不同短路故障需要重新建模,且无法研究健康状态时线圈对电机性能的贡献等问题,该文提出一种基于线圈子单元的永磁同步电机健康与定子绕组... 详细信息

针对相绕组为基本单元的永磁同步电机定子绕组短路故障数学模型,存在故障空间位置影响无法计及、不同短路故障需要重新建模,且无法研究健康状态时线圈对电机性能的贡献等问题,该文提出一种基于线圈子单元的永磁同步电机健康与定子绕组短路故障数学模型(APM)。首先,将每个线圈分割为多个线圈子单元,分别建立各子单元的电压、阻抗和空载反电动势等物理量的矩阵方程,利用基尔霍夫电压定律建立所有子单元的电压方程,建立电机的电磁功率和转矩方程。其次,利用有限元法和拟合法建立考虑槽内空间位置关系的线匝电感矩阵,通过矩阵变换得到计及位置信息的子单元电感矩阵。然后,在Matlab/simulink中建立APM的仿真模型和图形化界面,通过修改抽头编号及图形化界面中短路电阻模块的连接位置,计算电机健康和不同类型定子绕组短路故障下的电磁特性。最后,有限元仿真和实验结果验证了模型的正确性和准确性,表明APM不仅可以精细地分析健康状态时线圈对电机性能的贡献,也可以高效、准确地分析线圈内部不同位置短路故障对电机性能的影响。该文研究可以为永磁同步电机的设计、故障诊断和容错控制提供依据。

关键词：永磁同步电机数学模型线圈子单元定子绕组短路故障矩阵方程

Drag reduction characteristics of recirculation flow at rocket base in an RBCC engine under ramjet/scramjet mode

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第3期37卷 104-115页

作者： Menglei LI Mingbo SUN Peibo LI Daoning YANG Bin AN Yizhi YAO jikai CHEN Taiyu WANG Jiaoru WANG Hypersonic Technology Laboratory National University of Defense TechnologyChangsha 410073China Department of Aerospace Science and Technology Space Engineering UniversityBeijing 101416China

To reduce the drag generated by the recirculation flow at the rocket base in a RocketBased Combined Cycle(RBCC)engine operating in the ramjet/scramjet mode,a novel annular rocket RBCC engine based on a central plug cone was proposed.The performance loss mechanism caused by the recirculation flow at the rocket base and the influence of the plug cone configuration on the thrust performance were studied.Results indicated that the recirculation flow at the rocket base extended through the entire combustor,which creates an extensive range of the"low-kineticenergy zone"at the center and leads to an engine thrust loss.The plug cone serving as a surface structure had a restrictive effect on the internal flow of the engine,making it smoothly transit at the position of the large separation zone.The model RBCC engine could achieve a maximum thrust augmentation of 37.6%with a long plug cone that was twice diameter of the inner isolator.However,a shorter plug cone that was half diameter of the inner isolator proved less effective at reducing the recirculation flow for a supersonic flow and induced an undesirable flow fraction that diminished the thrust performance.Furthermore,the effectiveness of the plug cone increased with the flight Mach number,indicating that it could further broaden the operating speed range of the scramjet mode.

关键词： Rocket-based combined cycle Ramjet/scramjet mode Plug cone Drag reduction k-x SST turbulent model

A high-performance electrochromic device assembled with WO_(3)/Ag and TiO_(2)/NiO composite electrodes towards smart window

在线全文

学校读者我要写书评

暂无评论

Frontiers of Materials Science 2024年第1期18卷 123-135页

作者： Haorui Liu jikai Yang Decai Nie Chunlei Liu Liumenghan Zheng Yining Mu Weijun Chen Chongqing Research Institute Changchun University of Science and TechnologyChongqing 400000China School of Physics Changchun University of Science and TechnologyChangchun 130022China

The choice of cathode and anode materials for electrochromic devices plays a key role in the performance of electrochromic smart windows.In this research,WO_(3)/Ag and TiO_(2)/NiO composite thin films were separately prepared by the hydrothermal method combined with electrodeposition.The electrochromic properties of the single WO_(3) thin film were optimized,and TiO_(2)/NiO composite films showed better electrochromic performance than that of the single NiO film.WO_(3)/Ag and TiO_(2)/NiO composite films with excellent electrochromic properties were respectively chosen as the cathode and the anode to construct a WO_(3)/Ag‒TiO_(2)/NiO electrochromic device.The response time(tc=4.08 s,tb=1.08 s),optical modulation range(35.91%),and coloration efficiency(30.37 cm^(2)·C^(-1))of this electrochromic device are better than those of WO_(3)-NiO and WO_(3)/Ag-NiO electrochromic devices.This work provides a novel research idea for the performance enhancement of electrochromic smart windows.

关键词： WO_(3)/Ag composite film TiO_(2)/NiO composite film electrochromic device

基于半周反电势残差的永磁同步电机局部退磁故障诊断

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

电机与控制学报 2023年第7期27卷 183-194页

作者：高彩霞李炳锟陈昊司纪凯聂言杰河南理工大学电气工程与自动化学院河南焦作454003 河南理工大学应急管理学院河南焦作454003 郑州大学电气工程学院河南郑州450001 陕西汉德车桥有限公司陕西西安710201

永磁体退磁故障的精准定量诊断,对于预防电机发生灾难性故障和系统运行维护策略的制定至关重要。为实现退磁永磁体定位及程度评估,本文提出了一种基于半周反电动势残差的局部退磁故障诊断方法。在定子槽内安装一个探测线圈,提取其反电... 详细信息

永磁体退磁故障的精准定量诊断,对于预防电机发生灾难性故障和系统运行维护策略的制定至关重要。为实现退磁永磁体定位及程度评估,本文提出了一种基于半周反电动势残差的局部退磁故障诊断方法。在定子槽内安装一个探测线圈,提取其反电动势残差信号并进行分区;将分区后的反电动势残差峰值作为特征量进行退磁故障类型识别,进而确定相邻两个永磁体的健康状态及退磁程度,利用一个旋转周期的信号确定所有永磁体的状态,具有侵入性小、计算量小和精确度高的特点。首先,介绍了探测线圈的安装及检测机理,建立了永磁同步电机退磁故障下的探测线圈半周反电动势残差数学模型;然后,提出了考虑支路环流的反电动势残差提取算法,有效提高了探测线圈反电动势残差提取的精确度;最后,建立了反电动势残差峰值与退磁永磁体位置及退磁程度的映射关系,并提出了退磁永磁体定位及程度评估算法,实现了永磁同步电机局部退磁故障的精准定量诊断。仿真和实验结果验证了所提方法的正确性和准确性。

关键词：永磁同步电机局部退磁故障定位程度评估数学模型探测线圈反电势残差

基于环轭型探测线圈的永磁同步电机局部退磁故障定位方法

在线全文

学校读者我要写书评

暂无评论

电机与控制学报 2023年第4期27卷 97-110,118页

作者：陈昊高彩霞桑晓晨许孝卓封海潮司纪凯河南理工大学应急管理学院河南焦作454003 河南理工大学电气工程与自动化学院河南焦作454003 西南交通大学利兹学院四川成都610097 郑州大学电气工程学院河南郑州450001

退磁故障的精准定位对于预防电机系统发生灾难性故障和制定系统运行维护策略至关重要。针对多极数永磁同步电机(PMSM)退磁故障情况复杂,退磁故障定位难的问题,本文提出一种基于环轭型探测线圈的PMSM局部退磁故障定位方法。该方法只需在... 详细信息

退磁故障的精准定位对于预防电机系统发生灾难性故障和制定系统运行维护策略至关重要。针对多极数永磁同步电机(PMSM)退磁故障情况复杂,退磁故障定位难的问题,本文提出一种基于环轭型探测线圈的PMSM局部退磁故障定位方法。该方法只需在定子侧安装3个环轭线圈以获取包含退磁故障信息的信号;基于3个环轭线圈的感应电势,运用信号的基本运算构造退磁定位信号并按一定的规则对其进行分区;利用分区后的退磁定位信号的波形识别退磁故障类型,确定对应区域退磁永磁体的状态;利用一个机械周期的信号确定所有永磁体的状态,进而实现退磁永磁体的精准定位。首先介绍了退磁定位信号的构造与建模方法。然后,利用所建立的分区数学模型研究退磁定位信号在预设故障类型下的波形。最后,提出基于退磁定位信号分区的局部退磁故障精准定位方法。仿真和实验结果表明所提出的方法能对任意多个永磁体退磁故障(退磁程度不低于10%)进行精准定位。该研究为PMSM故障定位提供新方法,为故障后的运行策略制定和维护策略制定奠定基础。

关键词：永磁同步电机局部退磁故障定位分区数学模型探测线圈感应电势残差