基于矢量控制变频器的异步电机节能控制系统研究

在分析了三相异步电机转差频率矢量控制、气隙(定子)磁场定向矢量控制、转子磁场定向矢量控制三种矢量控制方案后,对基于转子磁场定向矢量控制方案的6SE70变频器的优点和在工程应用中安全可靠、高效节能的控制效果进行了详细分析和研究.     

1140V变频调速系统在梭车的应用

介绍了梭车变频调速系统的主回路和控制回路,通过对控制系统的分析、梭车运行工况和现场试验,优化了变频器的参数,针对变频器的矢量控制,确定了矢量控制下的电机参数,并分析了变频器运行中常见的故障,给出了故障原因和采取的策略。     

基于矢量控制变频器的储柜底带出料均匀性的实现方法

为控制储柜底带出料均匀性,利用矢量控制型变频器在0赫兹运行时仍然释放激磁电流和转矩电流合成的矢量电流并产生电磁转矩的原理,为此,重新设计了储柜底带变频器的PLC控制程序和电机冷却系统。结果表明在储柜底带暂停出料期间底带电机变频器在0赫兹运行时释放的矢量电流产生的电磁转矩抵消了底带后退时的作用力,防止或减少底带反转后退,实现了底带出料的均匀性。因此矢量控制型变频器可以工作在0赫兹并能对底带电机进行良好驱动控制。     

1140V变频调速装置在履带式采掘设备中的应用

介绍了履带式采掘设备变频调速装置的主回路和控制回路,通过对控制系统的分析和现场试验,设置了适合采掘设备工况的变频器参数,针对变频器的矢量控制,确定了矢量控制下的电机参数,并分析了变频器运行中常见的故障,给出了故障原因和采取的策略.     

矢量变频器在机床性能改造中的应用研究

变频器作为一种智能调速"元件",以其多用途、高可靠性和明显的节电效果迅速广泛地应用于各种大型自动化生产线和各类电机控制上.本文介绍了SIEMENS公司生产的CUVC矢量变频器的性能,并介绍了将其应用在X62W万能铣床变频调速中的控制方式和方法.     

微细扁线材生产装备的收放线张力控制

介绍了微细扁线生产的三种张力控制方案,在分析通过磁粉离合器、张力传感器、矢量变频器实现张力控制的基础上,重点叙述变频器张力控制方案的原理,并对其可行性进行分析。     

基于PLC与矢量控制变频器的电梯位置检测及速度控制的实现

本文介绍了由可编程控制器与矢量控制变频器构成的高性能电梯调速系统的硬件组成及控制原理;分析了电梯位置检测及速度控制的机理和实现方法;测试曲线表明采用可编程控制器与矢量控制变频器组成的电梯控制系统,平层精度高,调速性能好。     

使用通用变频器离线测量异步电机参数

异步电机电路参数通常可从异步电机制造厂家获得,也可以通过变频器自带的电机自适应功能获得。但有时现场调试会遇到一些特种异步变频电机,无法获取电机厂家关于电机定转子电阻和漏感等的数据,变频器的电机自适应功能又通不过,导致变频器矢量控制性能不佳,影响整机运行性能。在现场条件有限的情况下,根据电机和磁通矢量控制的基本理论,文中提出新的算法,仅利用现场通用变频器,通过空载和满载试验就能测量出异步电机参数,并将之用于变频器磁通矢量控制。此算法对于检测电流和检测电压的要求不苛刻,有一定的实用价值。     

电主轴变频调速控制与参数匹配

分析了恒转矩型和恒功率型电主轴的转矩、功率与转速的关系，采用MM440系列变频器进行调速控制，通过合理设定变频器参数，建立了适合恒转矩型和恒功率型电主轴调速的变频器U／f控制曲线。对电主轴的矢量控制做了探讨，说明了电主轴矢量控制的优点、限制条件和参数调整方法。     

变频控制技术在双电机同步驱动同一负载中的应用

分析了双向拉伸薄膜装备横向拉伸机(TDO)双电机刚性连接同步驱动同一负载的负载平衡控制问题,提出了采用西门子6SE70系列矢量控制变频器解决负载平衡控制问题的具体方案,并对各控制方案进行了比较和分析,经应用证实控制效果良好,满足生产工艺要求.     

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...     

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。     

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.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.