选择性有源滤波器治理12脉波整流器的谐波

文章介绍12脉波整流器应用选择性有源滤波器抑制谐波电流和补偿无功,采用基于瞬时功率理论的谐波和无功电流检测方法。对有源滤波器和负荷系统进行仿真,并对仿真结果进行详细分析。仿真结果表明：基于瞬时功率理论的谐波和无功电流检测方法可以准确、实时地检测出三相电流中的任意次谐波及无功电流,有源滤波器抑制11次和13次谐波电流,并补偿无功。     

基于dq坐标变换的谐波和无功电流检测法

介绍一种基于dq坐标变换的谐波和无功电流检测法，并对该方法进行了理论分析和仿真研究。仿真结果表明，这种检测方法无论电源畸变与否都可以准确检测出谐波和无功电流。     

三相无功电流的数字化检测变送与应用设计

介绍一种测量无功电流的数字化方法，对检测电路原理进行了深入探讨，详细介绍应用该方法设计的数字化三相无功电流远程检测网络系统的软硬件设计原理，并对减小测量误差及提高精度的措施进行了分析。检测终端采用微处理器内核，电路精度高，简单可靠。远程检测网络系统采用电流环型总线，便于计算机化集中控制与管理。     

基于瞬时无功功率理论的谐波和无功电流检测

介绍了基于瞬时无功功率的谐波和无功电流实时检测理论。该理论突破了传统的平均值功率定义,系统的定义了瞬时无功功率、瞬时有功功率。可实时的检测电力系统中的谐波和无功电流。讨论了瞬时无功功率理论,得出基于瞬时无功功率理论的谐波和无功电流检测算法。结果表明,这种检测法能为抑制谐波和无功补偿提供可靠的谐波及无功分量。     

基于瞬时无功功率理论的谐波和无功电流检测

介绍了基于瞬时无功功率的谐波和无功电流实时检测理论.该理论突破了传统的平均值功率定义,系统的定义了瞬时无功功率、瞬时有功功率.可实时的检测电力系统中的谐波和无功电流.讨论了瞬时无功功率理论,得出基于瞬时无功功率理论的谐波和无功电流检测算法.结果表明,这种检测法能为抑制谐波和无功补偿提供可靠的谐波及无功分量.     

谐波和无功电流检测方法分析

谐波、无功和负序电流的准确与快速检测是决定配电网静止同步补偿器性能的关键因素之一。文章对p-q法、ip-iq法、改进ip-iq法的检测性能进行了理论和仿真分析,并在TMS320LF2407A实验系统中对它们进行了实验研究。结果表明,只有当三相电压对称无畸变时,p-q法才能准确检测谐波、无功和负序电流分量;不管电网电压是否对称畸变,改进的ip-iq法都能精确检测正序基波有功电流,但计算量大;即使电网电压不对称且畸变,ip-iq法也能准确检测谐波电流,而对谐波、无功和负序电流的检测精度取决于锁相环对正序基波电压相位的检测精度,但该法的计算量小,更易于数字化实现。     

有源电力滤波器的谐波检测方法研究

针对基于FFT的谐波检测和ip-iq法的不足，详细分析并实现了有源滤波器基于旋转坐标系下进行坐标变换的谐波检测方法。该方法在电网电压存在不对称情况下均能很好地检测和补偿电网中的谐波电流和无功电流，根据需要，还可以检测和补偿任意次谐波电流。理论分析和实验结果验证所提出的控制方法的有效性，基于旋转坐标系下进行坐标变换的谐波检测方法的有源电力滤波器具有良好的工作性能。     

补偿电铁谐波及无功电流的有源滤波器的研究

研究应用于补偿电铁谐波及无功电流的单相有源滤波器,基于鉴相原理的谐波及无功电流检测法适合于作为电铁谐渡及无功电流的检测方法,改进的三角波调制电流控制方法能对电铁系统中的谐波及无功电流起到很好的补偿作用.仿真结果表明有源滤波器能够达到综合补偿的目的.     

新型低压无功补偿器的设计

主要介绍了基于ATT7022B和ST-SRC或ST-SRCS-4智能开关的新型无功补偿统。该控制器通过高精度多功能三相电能专用计量芯片ATT7022B实时检测电网的电压、电流、功率因数、无功电流和无功功率,并有CAN总线通信接口。ST-SRC或ST-SRCS-4智能开关可在电压或电流过零点时动作,并可以通过CAN总线接口与和无功补偿控制器进行通信,最终使电容器组按一定的规律进行投切,最终实现无功补偿。     

单相SVG的基波无功电流跟踪算法

作为改善电能质量的一种重要手段,静止无功发生器SVG要求快速的检测出负载电流中的无功分量.本文针对直接电流控制的用户端单相SVG,提出一种新的单相无功电流的跟踪算法,该方法通过在一个计算周期内基波周期前后一段数据的比较来快速跟踪无功电流.仿真表明该方法正确可行.仿真波形可以看出,在一个周期内可以实现对无功电流的准确提取,而且对电流变化跟踪效果好,防干扰能力强.算法简单快速,只需两个乘法器,且易于实现.     

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.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

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.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

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.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.