软启动装置在大型淬火水槽上的应用

简述了大型电动机新控制启动装置软启动器的原理，功能和特点，以及软启动器在淬火水槽泵电机上的应用情况，并针对软启动器的各种特点提出了符合淬火水槽况的控制方法，对于提高有效生产时间及降低维修周期起到积极作用。     

异步电动机软启动器设计

异步电动机启动电流大,频繁启动易造成电机损坏,采用单片机控制的软启动器可实现电机的限流、限压。该异步电动机软启动器以单片机MSP430F149为核心,通过软件设计实现电机的启动和保护,具有电路结构简单、稳定性好的特点,尤其是具有极强的抗干扰能力,适合应用于工业环境下,应用前景广阔。     

一种实用型电机软启动器的设计与实现

为降低电动机启动时的启动电流、增大启动转矩和减少对电网的影响,设计并实现了一种实用型电机软启动器。以32位单片机STM32F103C8T6为主控核心,采用复杂可编程逻辑器件产生软启动触发脉冲控制信号。根据实用型电机软启动器的组成结构,分别对其内部模块、电路控制系统、检测系统平台进行了研究、设计及制作;对电机软启动器在实验室条件下进行多次测试并研究分析影响其启动效率的一系列因素。MATLAB仿真结果和实验数据表明:该软启动器带载能力强,具有启动电流小、启动转矩大的优点。     

磁控式异步电机软启动器的功能分析与应用

介绍了一种新型磁控式软启动器，该软启动器通过调整磁场强度，改变感抗，用以改变加在电动机上的电压，实现电机的软启动运行，该软启动器在扼制启动电流和避免高次谐波方面优于其他启动器。     

高压交流异步电动机的软起动

随着电力电子技术的发展,智能性软启动器得到广泛应用。软起动是一种集电机软起动、软停车、轻载节能和多种保护功能于一体的新颖电机控制装置。本文从不同的角度介绍了大功率电动机的软起动方式、软启动的特点以及软启动的应用,它具有多种电动机的保护功能,从根本上解决了传统降压启动设备的弊端。     

长沙奥托软启动器在斗轮机皮带控制系统中的应用

使用长沙奥托QB42-110全数字交流电机软启动器,对悬臂皮带驱动机构电动机进行软启动控制,使得输出电压平稳,实现电机使用最小启动电流,得到最佳转矩,平稳起停。     

基于模糊控制的异步电机软启动器的研制

基于无速度传感器和模糊控制,提出了一种异步电机软启动器的研制方案,将无速度传感器应用到异步电动机的软启动器中,采用模糊控制器来实现电流控制,使异步电机软启动过程中存在的非线性控制得到了改进和提高。以MC9S12DG128单片机作为其控制器,对软启动控制系统的硬件电路和软件程序进行了设计。实验结果表明:该软启动器结构简单,系统损耗减小,稳定性和精度得到了提高,其中电压精度达到了0.01 V,对电机及其拖动系统有更好的保护作用。     

基于PLC的交流电动机软启动器

本文详细介绍了一种以PLC为控制核心的电动机的软启动器的工作原理、硬件配置与软件流程图,以及该软启动器的特点。     

软启动器在渣车控制系统应用

简单介绍软启动器的工作原理和软启动控制电动机启动的优点,就软启动器的启动特点、控制方式及在渣车控制系统中的实际应用等方面进行重点阐述。     

基于单神经元PID控制器的异步电动机软启动器仿真

阐述了异步电动机软启动的基本控制原理,利用Matlab/Simulink仿真工具,建立了异步电动机软启动器系统仿真模型。在此基础上,进行了基于单神经元PID的异步电动机软启动器的仿真试验。仿真结果表明,单神经元PID控制技术能够较好地控制电动机启动过程中的电流实现限流启动,有效地降低启动过程大电流的不利影响,满足电动机软启动要求。     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.