电压空间矢量研究及Matlab仿真

介绍了空间矢量脉宽调制（SVPWM）的基本原理,详细分析了在Matlab环境下实现电压空间矢量的方法,最后给出结合永磁同步电机（PMSM）调速系统的仿真实验结果。仿真结果表明,该系统具有良好的鲁棒性和快速性,对电机参数不敏感,为研究永磁同步电机调速提供了一定的理论和仿真依据。     

永磁同步电机变频调速 矢量控制系统的研究和仿真分析

以电压空间矢量控制的基本原理和概念为基础,结合Matlab/simulink软件包构建了永磁同步电机变频调速矢量控制系统的仿真模型,并详细给出各模型的具体参数。仿真结果显示,该方法简单,控制精度高,用于永磁同步电动机变频调速系统中具有良好动、静态性能。     

通用变频器控制系统设计

随着电力电子技术、微处理器技术以及新的电机控制技术的发展,交流调速性能日益提高。本文给出了一种基于数字信号处理器（DSP）和智能功率模块（IPM）的SVPWM矢量控制变频调速系统的实现方案,在阐述矢量控制和空间电压矢量脉宽调制基本原理的基础上,详细介绍了系统的硬件组成及软件的设计方法。仿真结果表明,该控制系统控制性能和...     

基于DSP的永磁电机空间矢量控制仿真应用

针对传统PI调节控制在电机启动、制动或转速突变过程中易饱和的问题,提出了一种基于电压空间矢量脉宽调制(SVPWM)电机控制解决方法,并建立永磁同步电机数学模型,同时以DSP(TMS320F2812)为核心芯片搭建控制系统硬件平台,构建三闭环伺服调速系统。最后,通过MATLAB/SIMULINK对控制模型仿真验证,仅用0.015s进入稳定运行状态,且10ms后进行速度切换,系统具备快速响应和较好的速度跟踪特性。     

基于SVPWM的永磁同步电机直接转矩控制系统的研究

将空间矢量脉宽调制技术(SVPWM)引入到了永磁同步电机的直接转矩控制(DTC)当中,实现了电压空间矢量的连续调节。定子磁链近似为圆形,有效地解决了常规DTC系统电磁转矩脉动较大的问题。在MATLAB/Simulink环境下搭建了永磁同步电机基于SVPWM的直接转矩控制系统的模型,对电机的多种运行状态进行了仿真,验证了控制理论的正确性和有效性。     

泵用永磁同步电动机变频调速控制系统设计

为了提高泵用永磁同步电机的工作效率,研制了一种永磁同步电机变频调速控制系统.该系统以80C196MC单片机为控制核心,采用简单的V/F变频控制方法达到较好的控制效果.针对该控制系统的硬件和软件实现进行了论述,并通过实验证明了该控制系统的可行性.     

永磁同步电机的零低速无传感器控制研究

文中介绍了基于高频注入法的无位置传感器控制实现了永磁同步电机初始位置的估计,控制系统采用了先进的控制策略:矢量控制策略和SVPWM(电压空间矢量脉宽调制技术),基于MATLAB/SIMULINK搭建了仿真模型,结果证明了基于高频注入法实现永磁同步电机无位置传感器控制系统算法上的有效性。     

永磁同步电动机调速控制系统的设计

为了提高永磁同步电机调速系统的调速性能,改善系统的自适应性和可靠性,设计一个基于矢量控制的永磁同步电动机双闭环调速系统。系统中采用一种新型的空间电压脉宽调制(SVPWM)技术控制逆变器的工作状态,使电机在运行过程中电子磁链矢量的运动轨迹逼近圆形磁链轨迹。在研究传统PI控制方法的基础上,引入了模糊控制,建立一种模糊PI的控制方法作为转速控制器,在MATLAB/SIMULINK环境下中建立系统的仿真模型,并分别对这两种情况进行MATLAB仿真,仿真结果表明:采用自适应模糊PI控制方法系统具有更好的动、静态特性。     

内置式永磁同步电机直接转矩控制的仿真研究

在永磁同步电机直接转矩控制系统的基础上,分析了内置式永磁同步电机的最大转矩电流比动态磁链控制。设计了基于SVPWM的磁链给定的直接转矩控制系统,通过电压空间矢量连续调节,减小了直接转矩中转矩脉动。在MATLAB/SIMULINK仿真模型下,对该系统进行仿真,验证控制系统的有效性。     

基于SIMULINK的永磁同步电机矢量控制系统仿真

根据永磁同步电机在A-B-C三相坐标系和d-q两相旋转坐标系下的数学模型,介绍了矢量控制的基本原理,然后在MATL AB中利用SIMULINK仿真平台搭建永磁同步电机矢量控制系统进行仿真,并对该系统进行实验验证。仿真实验验证的结果表明:该系统的正确性和良好的控制性能,为永磁同步电机矢量控制系统的设计提供了良好的理论基础...     

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.