Powerful platform

Bringing power to one of the world's largest oil and gas platforms was not easy, but Troll A in the North Sea is now reaping the benefits. In February 2005, the world's first offshore HVDC transmission was successfully commissioned. Consisting of two parallel 40 MW transmissions connecting the Troll A gas platform in the North Sea, with the mainland 132 kV grid via polymeric DC cables, the offshore module was designed by ABB in collaboration with Statoil. Electrical power is supplied from the shore - for both the power supply and compressor drives - which gives way to a host of benefits. It cuts emissions and leads to a significant cost savings of oil companies. In addition, transmission of electrical energy from shore involves less maintenance and higher availability     

Coupler talk

The most common use for a coupler is a directional power monitor. Although a somewhat mundane application, it is a very useful one. The author had previously thought and that there may be important practical applications for these devices that lie outside of the normal laboratory measurement function. This analysis leads into another application, which is the use of a directional coupler as an asymmetrical power combiner     

制造强国战略

制造业是国民经济发展的命脉,纵观国际发展态势,制造业不仅推动了全球经济的发展,还提高了全人类的生活水平。从制造业的重要性出发,阐述了制造业对经济发展、人民生活水平提高、国防科技进步等方面的重要作用;探讨了中国制造业目前的发展现状——中国已经是制造业大国,但还不是制造业强国;从宏观和微观两个层面探讨了制造强国战略的实施方向。同时,制造业的发展离不开人才,剖析了人才培养面临的问题及解决方式。     

建设统一坚强的智能电网

1 明确智能电网的定义 智能电网就是一个利用现代网络通讯、计算机等技术与电气设备结合起来,实现电网在能源配置方面更环保(主要是污染物和温室气体排放最低),能源配置效率更高(即电网自身损耗最低),智能电网建设成本更节约,能源使用更安全,即电网稳定性更高、设备可靠性更高,人员得到更安全的工作环境,用户平均停电时间更短,并使发电商与用户以及电网管理者实现有效互动,出现故障后能最大限度地保证用户的基本需求并用最短的时间恢复到正常状态.     

一种具有强鲁棒性的伺服系统

按常规方法设计的伺服系统,在系统对象参数大范围变化时,其动态性能明显下降,以致不能正常工作。本文设计了一种无源自适应控制器,这种控制器可以克服系统对象参数大范围变化或外界干扰的影响,保持系统的频率特性基本不变,因而大大提高系统的鲁棒性。这种控制器可以用无源器件组成,也可以用微机软件实现。实验表明,这种伺服系统,在系统对象参数变化5～10倍时仍能正常工作,表明了该系统具有很强的鲁棒性。     

Teaching computers to talk right

The author discusses the use of default hierarchies to allow for the rules and exceptions in pronouncing English words and names correctly. She explains a default hierarchy of rules as a system of knowledge representation that combines the advantages of expert systems and neural networks. Their architecture and training are described     

Telephones you can talk to

A speaker-dependent speech recognizer for connected sequences of digits that uses a time-delayed neural network (TDNN) is described. The advantage of using a TDNN is that, at any given instant, acoustic features of the speech signal for a past interval of time up to the present can be observed simultaneously. Thus, once the system is trained, no detection of boundaries between words is necessary for the recognition. Instead of parsing the speech signal into words, or even further into phonemes, and then recognizing each word or phoneme by some process, the TDNN analyzes the signal in a continuous manner, word recognition units being activated as their corresponding words are completed in the input speech signal. A system of this type will most likely be incorporated in the very near future into a voice-activated telephone     

强大的Power Vision电能分析功能

详细介绍了IDEAL的Power Analyzer 800系列电能质量分析仪强大的软件分析功能。     

赛米控携最强智能功率模块出击亚洲风能大会 最大功率达1MW,特别适合风力发电应用

功率模块市场的领导者赛米控(SEMIKRON)在日前举办的2007亚洲风能大会上展示了旗下蓄势待发的SKiiP系统,一款集成了完美匹配的冷却系统、栅极驱动器、电流传     

信息化带动工业化--电器基础知识讲座(一)PLC--工业自动化的有力武器

随着国民经济和工业技术的不断发展,近几年来,"PLC"这个名词已经越来越多地被人们所提到,所听到.     

大功率LED照明灯具的应用与探讨

该文通过对大功率LED光源在城市照明灯具方面的应用现状和性能进行分析,具体阐述了目前条件下LED光源在照明灯具应用设计中的几种应用方案,通过对应用方案的简单分析,说明了针对不同的应用场合和灯具类型,如何合理选择适宜的LED光源以便设计出性价比良好的灯具。同时我们也认识到LED真正用于照明灯具所要面临的技术上的挑战和前所未有的市场机遇,希望业界能够共同携手,为我国LED照明产业的繁荣进步而不懈努力。     

核电"十二五":大国走向强国

"在确保安全的基础上高效发展核电",<中共中央关于制定国民经济和社会发展第十二个五年规划的建议>对我国核电发展作出了明确要求.从"适度发展"到"积极发展"再到"高效发展",我国核电将迎来又一个新的发展时期. 大规模发展条件已具备     

为东秦崛起提供强劲动力——渭南市副市长雷孟斌

地方经济发展需要坚强电网支撑,电网发展需要各级政府强有力的支持,双向互动,实现双赢.陕西省电力公司制定的渭南电网“十一五“发展规划,紧紧围绕当地国民经济和社会发展“十一五“规划,多方征求意见,体现了电力服务地方经济社会发展的高度的责任感和使命感.我代表市委、市政府及全市人民对陕西省电力公司及渭南供电局长期以来为当地经济社会发展所做出的突出贡献表示衷心感谢!……     

Powerful software to learn by [power systems CAI]

Many students have trouble understanding the concepts and mastering the analytical skills required in their first power systems course. This becomes apparent in subsequent courses when they falter in applying those concepts and skills. They may lose interest in power systems, and may drop out. Our overall project was aimed at developing educational facilities with an integrated laboratory for a power systems course. To this end, a software package called PowerGraf was developed to help students learn and to make the subject more interesting. It is an interactive and comprehensive software package for supplementing what is learned in the classroom, the laboratory and in the student's self-study. It is also an excellent demonstration tool. The package is truly designed for students with little understanding of power systems     

Coupler talk - take 2 [Microwave Bytes]

In this paper, it is necessary to invert the phase of one of the signals to obtain the desired 100% power addition in the output coupler. Only in the equal power split case ( i.e., 3-dB couplers) can the same effect be obtained more conveniently by the reverse connection of the two equal power outputs; this property is, of course, widely used to make balanced amplifiers     

新世纪电池强国梦——访中国电池工业协会副理事长兼秘书长王敬忠

重点介绍了90年代以来中国电池工业所取得的成就.近几年来,中国电池工业协会迅速适应市场经济,引导企业投入市场竞争,有力地促进了中国电池工业的发展.展望下世纪,协会表达了实现电池强国梦的决心.     

大功率PWM互补型直流斩波稳压控制器的研究

本文介绍一种利用他激式高频PWM斩波技术完成的大功率直流稳压电源装置，进行了线路原理分析并给出了关键技术参数的选取原则及计算方法。     

High Frequency LIMM - A Powerful Tool for Ferroelectric Thin Film Characterization

In this work, the laser intensity modulation method (LIMM) is applied to the investigation of sputtered self-polarized PZT thin films. A previous analytic solution of the LIMM Fredholm integral equation of the first kind by use of the Mellin transform is generalized and limitations of this approach are discussed. The numerically reconstruction of the pyroelectric coefficient profile is based on a eight-layer thermal model. The profile reconstruction was performed using MATLAB software containing algorithms for the inverse solution of the appropriate Fredholm integral equation and a Tikhonov regularization method for stable numerical solutions. Optimized algorithms for thermal parameter determination from the low frequency part of the pyroelectric current spectrum are presented. The impact of thermal parameters on the reconstructed profile was investigated. Monte-Carlo simulations were used for a comparison of different approaches for the regularization parameter estimation.