新品快报

理想工业公司推出全新电压／谐波监测仪美国理想工业公司(IDEAL)推出了一款新型电压／谐波监测仪61-830,这种功能强大的故障定位工具能够对电压骤降、骤升、脉冲和谐波进行精确的探测和记录。无论是内在或     

动态电压恢复器控制策略研究

动态电压恢复器是抑制电压跌落对敏感负荷影响的有效装置。当动态电压恢复器工作在不对称电压下时,逆变器将会持续地从电源侧吸收有功功率,引发直流侧电压泵升,严重时会损坏储能及功率开关器件。针对该问题,文章提出一种复合控制策略,即采用相移控制技术来减少逆变器对有功能量的吸收,从而抑制动态电压恢复器直流电压的泵升;采用双闭环控制技术对电网电压跌落进行抑制,提高了负载的稳定性。仿真结果表明,该复合控制策略可使动态电压恢复器具有更好的负载适应性,且使直流侧电压得到很好的抑制。     

Linear推出双输入1．2A锂电池充电器

美国理想工业公司（IDEAL）推出了一款新型电压／谐波监测仪61—830，这种功能强大的故障定位工具能够对电压骤降、骤升、脉冲和谐波进行精确的探测和记录。无论是内在或外在的电能质量问题，利用61—830都可以一览无余。其最大特点是设置简单，不需要计算机或特殊软件的帮助，即可及时报告电压事件发生和持续的时间以及严重程度，为电能质量分析开辟了新的途径。     

表面温度信号快速发生装置硬件设计

针对表面温度信号需要快速变化的场合,研制了一个表面温度信号快速发生装置,该发生装置包括半导体制冷器、水冷系统、红外传感器、液晶显示等模块.采用半导体制冷器作为温度信号发生器件,采用桥路改变半导体制冷器两端电压极性,为改变装置升降温速率采用调压电路实现半导体制冷器两端电压连续可调,采用红外传感器检测表面温度以实现闭环控制...     

供电系统中的电压暂降

随着信息科技和其他高科技产业的飞速发展,电压骤降对新型电力负荷的影响日趋严重,由此造成工业生产中断而引起的经济损失相当巨大。本文首先简单介绍了电压暂降的定义、产生的原因及危害;其次详细分析了电压暂降的特性及变压器对电压暂降传播特性的影响;最后提出了只有供电方、设备制造方及用户三方合作,才能把电压暂降对敏感设备的危害降低到最小。     

不对称故障下STATCOM的运行和控制

随着电网负荷日益复杂化,电网常出现不对称故障,而且传统静止同步补偿器(STATCOM)存在参数整定难,计算复杂的缺点,故不能很好地实现无功电流的实时补偿和装置的稳定运行.通过对不对称故障状态下逆变器直流侧电压失稳机理的分析,提出一种基于正负序矢量分别定向控制新策略.该控制策略对不对称电压电流进行矢量分解,并在正负序网络下对各电矢量分别进行定向控制,从而可以有效抑制输出谐波分量,稳定直流电压,并实现动态无功补偿.同时结合能量泄放装置实现STAT℃OM在故障下的不脱网运行.该控制策略简单可靠,具有高鲁棒性,易于实现;仿真和实验结果表明,采用提出的控制方法可以及时穿越不对称故障,并有效补偿系统无功,稳定直流侧电压.     

有源滤波器参考电流和电网电压的同步

提出一种关联型有源滤波器参考电流的测定方法，并推导出一种新的同步原理，通常的同步方法是基于检测电网电压过零点，由于电压信号对干扰很敏感，尤其在过零点附近，容易产生错误的同步脉冲信号，导致完全错误的参考电流，所提出的新方法在线检测电网电压和负载电流，并在线计算电源基波电压，不仅可完全补偿无功功率，抑制谐波电流，而且能快速跟踪负载电流的变化。     

飞轮电池提高离网型风力发电系统稳定性研究

针对目前风力发电系统中储能装置(化学电池)的不足,设计了采用飞轮电池作为离网型风力发电系统的储能装置,提出了飞轮电池快速充、放电的控制策略。在系统的充电方式下,采用了感应电机的矢量控制算法;放电方式下,采用了以直流母线电压为控制信号的控制策略实现了直流母线电压的自动调整,达到了稳定系统的直流母线电压的目的。仿真结果表明,该储能装置能实现稳定风电场直流母线电压的作用,从而有效地提高离网型风电场的电能质量和稳定性。     

电流互感器电子式负荷装置研究

电流互感器误差检定一般需要检测额定负荷和轻载负荷下的误差,传统一般采用阻抗式负载箱切换方式进行负荷设定。本文研制一种新型电子负荷装置,通过电流源和电压源叠加的方式,改变电压源幅值和相位,即可满足0~1.0任意功率因数和0~60VA任意负载的设定,实验证明该电子负荷装置满足互感器检定要求,同时也分析了装置设计过程中遇到的各种问题及其不足之处。     

小功率光伏发电逆变器的设计

设计以TMS320LF2407型DSP为核心的小功率光伏发电逆变器。主电路采用全桥式逆变器,针对传统PI控制的不足,采用了PI控制和重复控制相结合的控制策略,以实现输出电流与电网电压可靠同步。采用了电导增量法实现了最大输出功率（MPPT）的快速、稳定跟踪。实验结果表明所设计的逆变器运行稳定可靠,可用于小型光伏发电系统。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.