单相电容启动异步电动机节能问题研究

针对单相电容启动异步电动机运行时功率因数比较低的问题,提出电动机启动并转入运行时,在其主绕组并联适当的电容器的方法,减少或省去电源对电动机提供无功电流,以减少线路损耗,提高电源功率因数,提高电源设备容量的利用率。     

永磁同步电动机直接转矩控制的效率优化

针对永磁同步电动机在轻载、高速运行时效率和功率因数下降的问题,提出了一种永磁同步电动机直接转矩控制效率优化策略。该策略通过分析电动机损耗与转矩、转速和定子磁链之间的关系,建立了考虑铁损的永磁同步电动机数学模型,导出了效率最优时的定子磁链幅值;将最优定子磁链计算模块嵌入直接转矩控制系统,构成了效率最优的永磁同步电动机直接转矩控制调速系统。仿真结果表明,该优化策略能有效降低永磁同步电动机功率损耗,提高电动机的运行效率。     

永磁同步电动机直接转矩控制的效率优化

针对永磁同步电动机在轻载、高速运行时效率和功率因数下降的问题,提出了一种永磁同步电动机直接转矩控制效率优化策略。该策略通过分析电动机损耗与转矩、转速和定子磁链之间的关系,建立了考虑铁损的永磁同步电动机数学模型,导出了效率最优时的定子磁链幅值;将最优定子磁链计算模块嵌入直接转矩控制系统,构成了效率最优的永磁同步电动机直接转矩控制调速系统。仿真结果表明,该优化策略能有效降低永磁同步电动机功率损耗,提高电动机的运行效率。     

单相感应电动机瞬态过程的SIMULINK仿真

根据单相感应电动机在d-q静止坐标系下的动态数学模型，用MATLAB软件中的动态仿真工具SIMULINK构造出电容单相感应电动机的仿真模型。通过实例对电容起动单相感应电动机和电容起动、电容运行单相感应电动机的瞬态特性进行仿真计算，并对仿真结果进行分析。     

一种高性能永磁同步伺服电动机绕组串并联换接方法及其仿真研究

为了扩展永磁同步伺服电动机运行速度的范围,提出了一种绕组串并联换接方法,详细介绍了该方法的实现,并对该方法进行了静动态仿真。仿真结果表明,绕组串并联换接可以在兼顾电动机低速与高速性能的前提下,大幅度扩展了永磁同步伺服电动机的运行速度范围,较好地解决了同一台电动机既要求低速大转矩,又要求高速大功率这一矛盾。     

基于单相高频电压法的永磁直线电机的功率角测量

为了解决低速和零速时永磁直线电机功率角的测量以及消除采用机械型传感器带来的安全、可靠性方面的问题,提出了基于单相高频电压注入法的永磁直线同步电动机功率角测量方法。在永磁直线同步电动机单相绕组中持续注入高频电压信号,通过检测得到高频电流信号,进而利用半周积分算法得到该电流的幅值,并利用永磁直线同步电动机的电流-电感-功率角之间的解析方程,获取电机的功率角。实验表明,该方法可靠性高、实用性强,且精度能够满足要求,适用于包括零速在内的永磁直线电机功率角的测量。     

用P111G控制电机启动

在工业上经常要用到三相异步电机，三相异步电机的起动有直接起动、降压起动和软起动等方式。直接起动又称全压起动，即起动时电源电压全部施加到电动机定子绕组上。降压起动即起动时将电源电压降到一定的数值后施加到电动机定子绕组上，待电动机的转速接近同步转速后，再使电动机在电源电压下运行。软起动就是使施加到定子绕组上的电压从零按预设的函数关系逐渐上升，直到起动过程结束，再使电动机在全压下运行。     

永磁同步电动机在现代变频控制方案研究及运行维护

本文分析了永磁同步电动机与传统电机在结构、调速、过载能力以及效率上的优点,介绍了现代工业中应用的前景,研究永磁同步电动机变频速率调整系统的设计方案。该论题分析阶段内,通过总结变频调速控制原理,了解永磁同步电动机运行状态、开展数学模型建立分析以及调速系统的设计操作,最终为永磁同步电动机变频调速提供了理论依据。阐述了永磁同步电动机在变频控制中的运行与维护。     

三相异步电动机的单相运行研究

近几年来,我国经济快速发展,但随之而来的是各类型能源的大批量消耗,不利于国家实体经济及相关产业项目的可持续发展。基于此,国家提出节能降耗的政策,并将其渗透在各行业的发展过程之中,其中,对于电动机装置优化改造项目而言,电动机节能降耗成为了电机理论研究及实践操作方面的关键内容,特别是三相异步电动机在单相电源中的应用,极大地增强了电动机的运行效率,而且,还扩大了电机的运行范围。本文就从剖析三相异步电动机在单相电源中的接线策略等细节方面着手,针对三相异步电动机装置的单相运行及其注意事项进行研究。     

永磁驱动技术在选煤厂异步电机中的降耗性能研究

针对选煤厂传统异步电机存在传动效率较低、能耗较高、维护成本较高及占地面积较大等问题,对选煤厂异步电机降耗性能关键技术展开研究,研发永磁驱动异步电机,建立永磁驱动异步电机数学模型。采用有限元分析法建立永磁异步电机的仿真模型,设定参数进行降耗数值模拟。结果表明,与传统的电动机相比,永磁驱动技术能降低81.25%的能耗。将该技术应用于山西某选煤厂异步电机场合,单班节省90 kWh,且永磁异步电机具有机械效率高、维护成本较低的优点,取得了满意的应用效果,具有一定的推广价值和市场前景。     

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。     

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。     

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.     

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.     

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     

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.