带有动态误差角补偿的PMSM新型转子位置观测器

在凸极永磁同步电机的几种观测模型中,等效反电势模型结构简单、不依赖转子转速、对电机参数不确定性的敏感度较低,也不受积分器引起的各项误差影响。在等效反电势模型的基础上,提出了一种带有动态误差角补偿的新型转子位置观测器。利用滑模观测器来估计等效反电势,提取含有误差项的转子位置信息。动态误差角补偿器进一步减少了定子直轴电流变化率引起的转子位置估计误差,改善了凸极永磁同步电机直接转矩控制系统的无传感器位置估算性能。相比于没有补偿动态误差角的观测器,提出的新型观测器具有如下优点:1)针对DTC系统转矩响应速度快的特点,新型观测器提高了在转速或负载瞬变情况下位置动态观测精度;2)针对DTC系统电流谐波大的特点,新型观测器减少了电流谐波引起的观测误差,提高了转速稳态时的位置观测精度。通过实验证明了该观测器的可行性和有效性。     

基于滑模观测器的永磁同步电机无传感器矢量控制

为解决永磁同步电机（PMSM）控制中机械式位置传感器带来的成本及可靠性等问题,将滑模观测器技术应用到PMSM矢量控制系统中。该系统采用滑模面及滑模等效控制方法,通过选择足够大的滑模增益,在观测电流和实测电流之间的误差上构建滑模面,对电机反电势进行观测以得到转子位置角,并基于Lyapunov稳定性判据对滑模观测器的收敛性进行了分析;建立了应用滑模观测器的PMSM无传感器矢量控制实验系统,设计了位置及速度滑模控制器。进行了1500r／min稳态及正负转速切换的角度估算实验,实验结果验证了该方法的有效性。研究结果表明,基于滑模观测器的无传感器控制策略能准确估计出PMSM的转子位置角,从而得到转子速度,且系统具有较好的动、静态特性。     

基于改进龙贝格观测器的控制系统的研究与仿真

由于传统永磁同步电机在实际应用中存在的问题,开发了永磁同步电机无传感器控制,适用于中高速范围的无传感器控制方法,主要是基于电机基波激励模型中与转速有关的变量反电势来估算转子速度和位置。在低速或零速时,反电势较小,有用信号的信噪比较小,通常难以提取,因此通过反电势的方法估算转子速度和位置难以实现。脉振高频电压信号注入常用于低速范围的无传感器控制方法中,而在中速范围内误差较大。将改进龙贝格观测器与脉振高频电压信号注入联系起来,解决控制系统在低中速的控制问题,降低转子位置估算与速度估算的误差。     

基于滑模观测器的永磁同步电机无传感器控制

永磁同步电机因具有功率密度高和动态响应速度快等诸多优点,在交流伺服传动领域具有明显的优势。永磁同步电机的高性能控制依赖于精确的转子位置信息,传统的机械式传感器成本高、体积大,限制了永磁同步电机的应用,无传感器控制技术是解决以上问题的一种有效途径。针对传统的永磁同步电机无传感器控制都是基于两相静止正交坐标上的数学模型进行研究的情况,设计一种基于滑模观测器的永磁同步电机无传感器控制方法。首先,建立永磁同步电机在两相同步旋转正交坐标系上的动态模型,并以此进行无传感器控制研究;其次,基于李雅普诺夫稳定性理论分析并设计了滑模观测器,得到感应电动势,并应用李雅普诺夫稳定性理论得到控制增益的约束条件;然后,引入一个低通滤波器削弱滑模控制固有的抖振,得到有效电动势,基于反正切函数对其带来的相位延迟进行补偿,提取位置信息;最后,通过仿真验证永磁同步电机无传感器控制方法对角速度和转子位置估计的有效性和鲁棒性。     

电动汽车永磁同步电机无位置传感器控制的研究

针对电动汽车永磁同步电机无位置传感器控制系统,在两相静止坐标系（d—B）内将滑模观测器法与MRAS结合,提出了基于模型参考自适应的滑模观测器,并利用自适应律估计永磁同步电机的转子速度。仿真和试验表明无位置传感器控制方法是切实可行的。     

基于滑模观测器的永磁同步电机模型预测电流控制研究

针对永磁同步电机无位置传感器高动态性能控制问题,对传统矢量控制存在电流内环PI控制器对系统性能的影响以及传统滑模观测器中动态转子位置角估计不准、稳态转速估计不精确等观测器性能进行了改进,提出了一种基于改进滑模观测器的永磁同步电机模型预测电流控制方法。根据永磁同步电机在同步旋转坐标系下的数学模型,选择了电机d、q电流作为状态变量,利用前向欧拉法推导出永磁同步电机d、q轴电流的预测模型。通过实时评估价值函数选出使得下一时刻电流跟踪效果最好的电压矢量,将其对应的开关状态作用于逆变器。同时,推导表贴式永磁同步电机的滑模观测器模型并对其观测出的转子位置角和转速进行补偿,得到较为精确的估算值。最后将算法在Matlab/Simulink进行了仿真试验。研究结果表明:所提出的控制方法动态性能好、稳态精度高。     

内插式永磁同步电机无速度传感器控制

为实现内插式永磁同步电机包含零速在内的全速度范围内无转子位置/速度准确检测,提出了一种无传感器复合方法。在高速范围,通过对扩展反电势的估算以得到转子位置和速度,低速时采用高频信号注入法进行转子位置检测。仿真研究结果表明,两种方法的结合既能在低速时准确地观测出转子的空间位置和速度,也能保证高速运行时较快的动态响应,适合于全速范围内电机的无传感器运行。     

无传感器永磁同步电机控制策略研究

永磁同步电机由于其结构简单、功率密度高等特点广泛应用于航空航天和新能源等新兴领域,其控制系统的开发也具有重要的意义。根据永磁同步电机的数学模型,设计出控制策略为矢量控制,SVPWM为调制方式,无位置控制方法(采用滑模观测器)的双闭环控制系统。通过Simulink仿真,比较了五段式和七段式SVPWM在控制效果上的区别,并为得到准确的转子位置估计值提供了参数选取方法。采取了提高系统精度和程序运算速度的措施,对滑模观测器相关参数进行了选择,并完成整体实验。实验结果表明,该系统能够实现基于SVPWM的永磁同步电机的无传感器控制。     

基于滑模观测器的无传感PMSM驱动控制系统的研究

为了研发一种可以取代传统有位置传感器的无传感器PMSM驱动控制系统,在分析滑模变结构控制理论(SMC)及永磁同步电机(PMSM)数学模型的基础上,建立起基于滑模观测器(SMO)的无传感PMSM矢量控制系统的数学模型,并搭建了采用id=0矢量控制策略的无传感PMSM矢量控制系统的仿真模型并进行仿真研究.结果表明,应用滑模...     

PMSM无速度传感器最优转矩控制系统的研究

针对永磁同步电机自身特点及转子位置和速度检测问题,采用最优转矩控制策略,提出了将脉振高频电压信号注入法和模型参考自适应法有机结合的新型无速度传感器的复合方法,设计了PMSM无速度传感器的SVPWM最优转矩控制系统.通过设计速度切换方案,实现速度的平稳过渡.此复合方法解决了单一方法不能在全速度范围内同时兼顾良好的动态、稳态性能的问题.仿真结果表明:该方法能可靠地实现包括初始磁位在内的转子位置和速度的精确检测和控制,系统具有优良的动态、稳态性能.     

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.