DPN—100分组交换机路由选择系统维护中常用的操作方法

ＤＰＮ１００分组交换机路由选择系统维护中常用的操作方法李虹１如何发现路由系统出现的故障（１）从ＮＭＳ工作站的告警窗口或本地操作终端上出现的告警码与故障部位关系如下：１０１４ＲＩＤ系统故障１０１８ＭＩＤ系统故障１０２２ＰＰＡＴ...     

中国交流聚丙烯薄膜电容器的去向

作者曾在国外公司任职，对ＭＰＰ电容器的国际市场情况有所了解。撰文探讨中国ＭＰＰ电容器的发展，且着重于市场方面。为中国该行业的企业决策者们提供一些国际市场情况，建议有基本条件的企业积极地进入ＭＰＰ电容器国际市场。     

高聚物PP/EPDM的 SEM分析样品制备参数选择研究

高聚物ＰＰ ＥＰＤＭ越来越广泛应用于工程技术中。利用扫描电子显微镜对其形态和结构的研究 ,促使我们最大限度地拓展ＰＰ ＥＰＤＭ材料的使用[1] 。对高聚物材料进行扫描电镜分析时 ,高质量的扫描效果应该是图像稳定、清晰。而这种效果不仅与扫描电镜本身的特性有关 ,而且在很大程度上依赖于分析样品的镀金参数选择。它极大地影响着ＳＥＭ图像的质量 ,甚至严重到无法观察与拍摄图像。因此 ,探讨高聚物ＰＰ ＥＰＤＭ样品的镀金适宜参数 ,具有一定的现实意义。实验部分将所要分析的ＰＰ ＥＰＤＭ材料用导电胶粘在扫描电镜样品台上 (断口面向…     

基于专用与通用DSP的实时图像处理系统

在研究机器人视学过程中，研制成功两种基于ＤＳＰ的实时图像处理系统。以４片专用ＤＳＰＩＭＳＡ１１０阵列为核心的系统，达到了８４０ＭＯＰＳ的处理速度，可实时完成各种大小模板的卷积，相关，滤波，边缘检测，增强及阈值化，线性与非线性变换等图像预处理和图像。两种系统均以ＰＣ机为宿主机，均配有独立的Ａ／Ｄ，Ｄ／Ａ系统。在设计中采用了创新的循环往复式流水线结构和ＤＭＡ，双口ＲＡＭ，多口共享存储区以及窗口映射等先     

3@—W—CDMA系统的扩频结构与扩频码

本文结构３ＧＰＰ Ｗ－ＣＤＭＡ的最新协议,介绍了Ｗ－ＣＤＭＡ系统的两次扩频结构,讨论了其中使用的ＯＶＳＦ码与扰码的主要特性及其在Ｗ－ＣＤＭＡ系统中的应用,文章的最后讨论了在工程实际中实时产生扩频码的方法。     

基于IMPP协议的网络寻呼系统设计和实现

详细介绍了网络及时消息服务的ＩＭＰＰ协议及其网络模型，根据该模型分析了网络寻呼系统的功能组成，并提出了网络寻呼系统的设计和实现方案。     

光栅扫描雷达终端图形控制板软件开发环境研究

本文介绍了ＴＭＳ３４０１０的基本功能、基于ＴＭＳ３４０１０设计的多总线图形处理系统软件开发研究的方法，并详细介绍了ＣＯＦＦ文件格式及其应用，为ＴＭＳ３４０１０在不同环境中的使用提供了一条行之有较的途径。     

STEPPER通用测试掩模的设计及使用

介绍了一种ＳＴＥＰＰＥＲ通用测试掩模（ＵＴＭ）的设计构成及各测试元素图形的作用。在此基础上，分析了电子束制作ＵＴＭ的误差，并阐述了ＵＴＭ的测试方法、数据处理及其对ＳＴＥＰＰＥＲ性能的影响。     

STEPPER通用测试掩模的设计及使用

介绍了一种ＳＴＥＰＰＥＲ通用测试掩模（ＵＴＭ）的设计构成及各测试元素图形的作用。在此基础上，分析了电子束制作ＵＴＭ的误差，并阐述了ＵＴＭ的测试方法、数据处理及其对ＳＴＥＰＰＥＲ性能的影响。     

单音串行HF MODEM的研究及DSP实现

论述了单音串行ＨＦ ＭＯＤＥＭ样机的系统工作原理及主要算法，包括解调器／判决反馈均衡器设计，自适应的均衡算法，载波恢复算法，定量同步算法，差错控制原理，传信率变化原理和系统联调原理等，给出了ＤＳＰ实时实现的方法以及室内模拟传输和上无线数据传输的实时实验结果。     

Low-Complexity MPPT Technique Exploiting the PV Module MPP Locus Characterization

This paper proposes a method for tracking the maximum power point (MPP) of a photovoltaic (PV) module that exploits the relation existing between the values of module voltage and current at the MPP (MPP locus). Experimental evidence shows that this relation tends to be linear in conditions of high solar irradiation. The analysis of the PV module electrical model allows one to justify this result and to derive a linear approximation of the MPP locus. Based on that, an MPP tracking strategy is devised which presents high effectiveness, low complexity, and the inherent possibility to compensate for temperature variations by periodically sensing the module open circuit voltage. The proposed method is particularly suitable for low-cost PV systems and has been successfully tested in a solar-powered 55-W battery charger circuit.     

A hybrid modified FA-ANFIS-P&O approach for MPPT in photovoltaic systems under PSCs

ABSTRACT

A modified firefly algorithm (MFO)-based adaptive neuro-fuzzy inference system (ANFIS) combined with the perturbation and observation (P&O) is used in this paper to track the maximum power point (MPP) in photovoltaic systems (PVs). The proposed method identifies and tracks the MPP in two stages. First, according to the irradiance on the solar panels, the ANFIS approximately identifies the MPP. In the second stage, the P&O method starts to act in the tracking cycle and initiates an accurate searching process from that point. The suggested hybrid method covers the problems of commonly-used methods, such as inability in detecting the global MPP under partial shading conditions (PSCs) and trapping in the local optima. Furthermore, the method provides significantly higher speed for the MPP tracking under various irradiance patterns. To prove the above-mentioned claims, the given approach is compared with the P&O method as a common method in the MPPT and particle swarm optimisation (PSO) which operates based on swarm intelligence. Simulation results obtained from MATLAB/Simulink environment show that the proposed method identifies and tracks the MPP under uniform irradiance and PSCs in a very short time of roughly 0.2 s.     

Toward multiple maximum power point estimation of photovoltaic systems based on semiconductor theory

Environmental conditions, such as temperature, non‐uniform irradiation, and solar shading, deeply affect the characteristics of photovoltaic (PV) modules in PV‐assisted generation systems. Several local maximum power points (MPPs) are found in the power–voltage curve of PV systems constructed by series/parallel‐connected PV modules under partially shaded conditions. The characteristics of PV systems change unpredictably when multiple MPPs occur, so the actual MPP tracking (MPPT) becomes a difficult task. Conventional MPPT methods for the PV systems under partially shaded conditions cannot quickly find the actual MPP such that the optimal utilization of PV systems cannot be achieved. Based on the p–n junction semiconductor theory, we develop a multipoint direct‐estimation (MPDE) method to directly estimate the multiple MPPs of the PV systems under partially shaded conditions and to cope with the mentioned difficulties. Using the proposed MPDE method, the multiple MPPs of the PV systems under partially shaded conditions can be directly determined from their irradiated current–voltage and power–voltage characteristic curves. The performances of the proposed MPDE method are evaluated by examining the characteristics of multiple MPPs of PV systems with respect to different shading strengths and numbers of the shaded PV modules and also tested using the field data. The experimental results demonstrate that the proposed MPDE method can simply and accurately estimate the multiple MPPs of the PV systems under partially shaded conditions. The optimization of MPP control models and the MPPT for PV systems could be achieved promisingly by applying the proposed method. Copyright © 2014 John Wiley & Sons, Ltd.     

A novel analytical model for determining the maximum power point of thin film photovoltaic module

Achieving the maximum power output from photovoltaic (PV) modules is indispensable for the operation of grid‐connected PV power systems under varied atmospheric conditions. In recent years, the study of PV energy for different applications has attracted more and more attention because solar energy is clean and renewable. We propose an efficient direct‐prediction method to enhance the utilization efficiency of thin film PV modules by tackling the problem of tracking time and overcoming the difficulty of calculation. The proposed method is based on the p–n junction recombination mechanism and can be applied to all kinds of PV modules. Its performance is not influenced by weather conditions such as illumination or temperature. The experimental results show that the proposed method provides high‐accuracy estimation of the maximum power point (MPP) for thin film PV modules with an average error of 1.68% and 1.65% under various irradiation intensities and temperatures, respectively. The experimental results confirm that the proposed method can simply and accurately estimate the MPP for thin film PV modules under various irradiation intensities and temperatures. In future, the proposed method will be used to shed light on the optimization of the MPP tracking control model in PV systems. Copyright © 2012 John Wiley & Sons, Ltd.     

Analytic Solution to the Photovoltaic Maximum Power Point Problem

Photovoltaic (PV) power has been successfully used for over five decades. Whether in dc or ac form, photovoltaic cells provide power for systems in many applications on earth and space. Its principles of operation are therefore well understood, and circuit equivalents have been developed that accurately model the nonlinear relationship between the current and voltage of a photovoltaic cell. With the improved efficiencies of power electronics converters, it is now possible to operate photovoltaic system about its maximum power point (MPP) in order to improve the overall system efficiency. Hitherto, this problem has been tackled using tracking (MPPT) algorithms that iteratively find the point of maximum power and respond to changes in solar irradiance accordingly. A mathematical manipulation that uses the mean value theorem is presented here that provides the analytic solution of a point in a close neighborhood of the MPP. It is thoroughly proved that this point is enclosed in a ball of small radius that also contains the MPP and therefore can practically be considered as the MPP. Since the solution is analytic, no iterative schemes are necessary, and only a periodic measurement is required to adjust to changes in solar irradiance. A circuit is implemented that shows the validity of the theory and the accuracy of the solution.     

Real-Time Identification of Optimal Operating Points in Photovoltaic Power Systems

Photovoltaic power systems are usually integrated with some specific control algorithms to deliver the maximum possible power. Several maximum power point tracking (MPPT) methods that force the operating point to oscillate have been presented in the past few decades. In the MPPT system, the ideal operation is to determine the maximum power point (MPP) of the photovoltaic (PV) array directly rather than to track it by using the active operation of trial and error, which causes undesirable oscillation around the MPP. Since the output features of a PV cell vary with environment changes in irradiance and temperature from time to time, real-time operation is required to trace the variations of local MPPs in PV power systems. The method of real-time estimation proposed in this paper uses polynomials to demonstrate the power–voltage relationship of PV panels and implements the recursive least-squares method and Newton–Raphson method to identify the voltage of the optimal operating point. The effectiveness of the proposed methods is successfully demonstrated by computer simulations and experimental evaluations of two major types of PV panels, namely: 1) crystalline silicon and 2) copper–indium–diselenide thin film.     

A PSO‐based maximum power point tracking for photovoltaic systems under environmental and partially shaded conditions

To increase the efficiency of photovoltaic (PV) systems, maximum power point (MPP) tracking of the solar arrays is needed. Solar arrays output power depends on the solar irradiance and temperature. Also the mismatch phenomenon caused by partial shade will affect the output power of solar systems and lead to the incorrect operation of conventional MPP tracker. Under partially shaded conditions, the solar array power–current characteristic has multiple maximum. This paper presents a maximum power point tracking (MPPT) with particle swarm optimization method for PV systems under partially shaded condition. The performance of the proposed method is compared with perturb and observe (P&O), improved P&O, voltage‐based maximum power point tracking and current‐based maximum power point tracking algorithms, especially, under partially shaded condition. Simulation results confirm that proposed MPPT algorithm with high accuracy can track the peak power point under different insolation, temperature and partially shaded conditions, and it has the best performance in comparison with four mentioned MPPT algorithms. Also under rapidly changing atmospheric conditions, the P&O algorithm is diverged. Copyright © 2013 John Wiley & Sons, Ltd.     

多孔径微穿孔板的主动吸声仿真研究

提出一种基于多孔径微穿孔板的主动吸声方法,在微穿孔板的空腔内横向放置可上下移动的隔板。从理论上说明了移动隔板改变声阻抗的可行性,利用数值分析法进一步比较了两种隔板移动方法对3种典型参数多孔径微穿孔板吸声性能的影响。对于15mm背腔的多孔径微穿孔板,在800~1 900Hz频段内平均吸声系数的分析结果达到0.85,表明该主动吸声方法的有效性,同时也为拓宽微穿孔板吸声体的频带提供了新思路。     

Dual-Module-Based Maximum Power Point Tracking Control of Photovoltaic Systems

The improved maximum power point tracking (MPPT) control method for small-scale dual-module photovoltaic (PV) systems is presented in this paper. With this method, the voltage and current information of each module are shared and utilized for the detection of the maximum-power point (MPP) without measuring power. This approach can be implemented in a simple structure, especially due to the elimination of memory and multiplication devices. The proposed method is verified by a hardware prototype of grid-connected dual-module PV systems with the proposed analog-implemented MPPT controller. In addition, practical issues of the proposed scheme are considered.     

LS MPP嵌入式计算机的系统软件设计

LS MPP是西安微电子技术研究所自行研制出的面向航空嵌入式应用的大规模并行图象处理机。其宿主机为自行研制的32位浮点RISC芯片，图象协处理系统为自行研制的MPP协处理器。文章论述了LS MPP计算机的系统软件设计，包括汇编程序、监控程序和C编译程序。