城轨交通车辆应急自牵引能耗需求分析及仿真

当牵引网无法正常供电时,城轨车辆通过车载储能系统作为储备电源实现应急移车,从而将列车安全行驶至车站疏散乘客,避免造成人身伤害和经济损失。针对上述情况,结合上海轨道交通11号线车辆电气参数及线路情况,基于PSCAD／EMTDC仿真软件对城轨车辆的电气特征进行建模并通过现场试验数据对仿真模型进行校验和修正。定性分析了车辆应急自牵引时不同运行工况对功率、能耗需求的影响。最后,基于上海轨道交通11号线昌吉东路站至赛车场站的区间线路,通过仿真模型计算车辆在特定工况下应急自牵引时的功率、能耗需求。     

基于PSCAD的两电平SVPWM的实现

根据两电平空间电压矢量脉宽调制(SVPWM)的基本原理,在电磁暂态分析软件PSCAD/EMTDC中,创建了自定义元件,以实现SVPWM功能。主程序用FORTRAN语言编写,主要包含参考矢量所在扇区判断、空间矢量工作时间计算、工作时间分配等功能模块。基于该元件,进行了仿真实验,仿真结果表明了元件的正确性。     

基于UMEC模型的三相变压器励磁涌流仿真研究

解决好变压器励磁涌流的识别问题是提高变压器差动保护性能的有效途径.以统一电磁等值电路建模理论为基础,结合PSCAD软件程序,建立了变压器励磁涌流的仿真模型,对励磁涌流的波形特征进行了详细的分析.仿真结果表明,励磁涌流特征明显,基于间断角及二次谐波制动原理的识别方法可靠,保护不误动.     

扼流适配变压器等效电路模型研究

在高速和重载条件下,为了防护大的不平衡牵引电流干扰并保证站内轨道电路可靠工作,采用了带适配器的扼流变压器,即扼流适配变压器。扼流适配变压器作为站内轨道电路中强弱电的结合部分,在轨道电路系统中起着非常重要的双重作用。因此,对扼流适配变压器进行建模仿真研究对于实现轨道电路的完整建模,保证列车安全运行具有十分重要的意义。首先建立了扼流适配变压器的并联等效电路模型,然后通过仿真及测试验证了模型的有效性。为了方便轨道电路系统的计算,最后建立了扼流适配变压器的四端网模型,并对不同载频条件下其四端网系数进行了仿真计算。     

基于PSCAD的十二脉变频器谐波分析

本文根据变频器的基本原理,利用电力系统暂态软件PSCAD搭建起十二脉冲变频器的仿真模型,对变频器模型的的各个结构和变频器产生的谐波含量进行了理论分析和研究;利用电能质量测试仪3196实地测量天津某钢铁企业中频炉变频器网侧整流部分的谐波含量,得到实测数据并与所建仿真模型相应处谐波数据进行比较,验证仿真模型的有效性。     

高速铁路牵引供电系统模拟仿真模型研究

为了准确摸拟高速铁路牵引供电系统,基于京津高速铁路客运专线提供的参数,设计了满足要求的高性能牵引网模垂、牵引变电模型、自耦变压器模型、故障模型等.建立高速铁路客运专线的动态模拟系统,能够为所模拟系统的继电保护装置的设计、功能测试和选型提供试验条件,并可用于故障、机车各种运行状况下的暂态特性研究.     

3种线路模型在牵引供电系统仿真中的对比分析

摘要：在牵引供电系统仿真研究中,针对输电线路的不同模型采用已有仿真软件来实现牵引供电系统的电气特性分析。在分析输电线路几种常用的数学模型的基础上,利用Matlab／Simulink对牵引供电系统的单线牵引网简化电路进行了仿真分析,重点研究了3种输电线路模型下牵引网的阻抗与频率特性和牵引网电压的损失。通过比较仿真结果证明所建立的模型的正确性,得出3种线路模型的适用范围。     

城市轨道交通与牵引供电系统电气模型研究

根据上海轨道交通1号线的牵引供电系统和列车电气拓扑结构,使用计算机仿真软件(PSCAD/EMTDC)在不同工况下建立了仿真模型.其中,牵引供电系统模型包括主变电站、牵引变电站、接触网和轨道;车辆模型包括牵引电机、主逆变器及其控制系统、制动电阻、滤波单元和辅助系统.模型将车辆和牵引供电系统结合起来,实现了初步联合仿真.仿真结果表明,所建立的模型能够准确反映在不同工况下车辆和牵引供电系统的特性,为进一步研究城市轨道交通和牵引供电系统奠定了基础.     

基于ZYNQ的动车组牵引网电能质量监测装置

针对动车组运营时牵引网的电能质量问题,文中基于ZYNQ平台设计了一种适用于动车组的牵引网电能质量监测装置。选用ZYNQ-7000系列的XC7Z045芯片作为装置主控芯片,采用模块设计,主要包括信号采集模块、信号处理模块和数据传输模块。信号采集模块使用AD9251芯片实现对电压电流原始数据的同步高速采集;信号处理模块利用主控芯片中内含的双核ARM Cortex-A9构成的PS以及FPGA构成的PL实现数据的高速处理;数据传输模块利用以太网芯片和网络变压器构建千兆网络电路实现数据的高速传输。实验结果证明：该装置性能稳定、计算精度高,各项参数计算误差在0.5%之内,满足动车组牵引网的电能质量监测需求。     

差动变压器式位移传感器参数化仿真技术研究

在建立合理的差动变压器式位移传感器(LVDT)电磁仿真模型的基础上,提出了一种基于脚本模板的电磁仿真参数化建模方法:首先将仿真建模过程录制成脚本,然后在脚本中添加标记形成脚本模板,最后将脚本模板中的标识动态修改为参数数值,实现了仿真模型的参数化建模;开发了LVDT参数化仿真系统并在工程中得到应用,显著提高了设计效率.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.