基于空间矢量调制的异步电机离线参数辨识

提出了一种基于空间矢量调制方式的异步电机参数辨识方法,可在电机静止状态下测量相关参数。该方法在考虑导通压降、开关延时、集肤效应和死区效应因素的基础上,提出了相应的补偿措施,提高了辨识的精度。并在以TMS320F28335为主控制器的异步电机无速度传感器矢量控制系统上进行实验,实验结果验证了该方法辨识的参数准确性高,可直接应用于无速度矢量控制系统。     

民航雷达电机无速度传感器矢量控制设计

针对民航雷达电机无速度传感器矢量控制系统进行了研究,在(/dq)坐标系下建立异步电机的数学模型,利用电动机定子电压方程和电流方程,采用模型参考自适应辨识算法,建立了一个基于转子磁场定向的异步电机无速度传感器矢量控制系统,并利用Mat Lab/Simulink软件对该控制系统进行仿真。     

基于模糊控制的定子电阻辨识研究

定子电阻的变化对异步电机矢量控制系统的性能具有重要的影响,准确获取定子电阻值在高性能电机控制系统中具有十分重要的意义。本文基于模糊控制理论,设计了一种结构简单的模糊定子电阻辨识器。在此基础上,根据矢量控制理论,采用Matlab/Simulink软件设计了异步电机矢量控制系统。仿真结果表明,辨识的定子电阻误差较小,系统响...     

异步电机无速度传感器矢量控制系统研究

根据模型参考自适应方法对异步电机转子转速进行辨识,结合应用SVPWM技术,构建了无速度传感器矢量控制系统。利用Matlab/Simulink对该系统进行了计算机仿真,仿真结果表明其对异步电机转子速度的估算具有较高的准确性,所设计的控制系统具有良好的动态性能。     

数据驱动技术在多电机同步系统中的应用

随着异步电动机在电机驱动系统中应用范围的逐步拓宽,多电机控制系统建模过程中需要处理的非线性问题更加明显,而且难度明显增加。通过使用局域模型的模糊辨识方法,在数据的聚类处理基础上,构建针对多台异步电动机的控制系统建模方法,能够较好地处理多台异步电机控制过程中的非线性问题。从控制系统的仿真效果来看,这种控制方法能够实现异步电机的同步控制,且控制效果良好。     

基于MRAS的异步电机无速度传感器的矢量控制

由于电机定转子参数的变化,利用一般的转子磁链对转速进行估算,将导致不能得到准确的结果。这里采用积分型转子磁链的参考和可调模型构建出一个基于MRAS的异步电机无速度传感器的矢量控制模型。该模型提高了矢量控制系统的动态性能并利用MATLAB,sIMULINK进行了异步电机无速度传感器矢量控制系统的仿真,验证了文中所采用的模型参考自适应的速度估算方法的可行性以及对参数误差的鲁棒性。     

无转速传感器抽油电机扭矩在线监测系统研究

介绍了一种无转速传感器抽油机异步电机的在线监测系统的软、硬件设计。论述了通过实时采集抽油机异步电机的三相电压和电流,计算电机的三相有功功率、无功功率和功率因数的方法。并利用电机模型参数,根据抽油机异步电机工作的特点,分析了实时计算电机定子磁链的幅值和相位的方法。同时提出了结合坐标变换下的定子电流计算,实时获取抽油机异步电机电磁转矩及转速的一般方法。     

无速度传感器感应电机控制系统转速辨识方法研究

无速度传感器感应电机控制技术已成为近年的研究热点,转速估计是无速度传感器感应电机控制技术的核心问题。在此对无速度传感器感应电机转速辨识技术进行了介绍,分析了几种比较典型的转速辨识方法的理论要点和优缺点,在直接转矩控制基础上设计了无速度传感器感应电机控制系统模型并进行仿真,给出了试验参数及仿真图形,并就今后的研究发展方向提出了看法。     

新型单绕组无轴承异步电机控制系统

研究了一种新型结构的单绕组无轴承异步电机,与传统的双绕组无轴承异步电机相比,采用一套绕组即可实现电机转子的悬浮和旋转。在分析单绕组无轴承异步电机新型结构和工作原理的基础上,推导出电机径向悬浮力和转矩部分的数学模型。针对单绕组无轴承异步电机的定子电流连接的复杂性,采用电流叠加控制方法,并设计基于气隙磁场定向控制的控制系统。在MATLAB/Simulink中建立控制系统的仿真模型进行仿真验证,并制作实验样机进行悬浮特性试验。结果表明,该方法控制的样机转速响应好、悬浮特性优良,从而验证了所提方法的正确性与有效性。     

基于MATLAB/Simulink的异步电机控制系统建模与仿真

本文在基于转子磁链定向的异步电机矢量控制理论基础上,针对磁链闭环的矢量控制系统中转子磁链易受电机参数影响的不足,提出了转子磁链开环的矢量控制方案。利用模块化思想,在MATLAB/Simulink建立磁链开环的矢量控制系统的各个功能模块,然后对各个功能模块进行有机的整合,构成矢量控制系统的仿真模型;仿真结果表明该系统具有良好的动态性能和抗干扰能力,进而验证了该控制系统设计的可行性和有效性,为实际电机控制系统的设计和调试奠定了理论基础。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.