西塞山发电厂发电机组同期系统分析与探讨

对西塞山发电厂发电机组同期系统进行了分析和改进,对提高发电机组同期系统安全性进行了探讨。     

A nine‐switch inverter for driving two AC motors independently

This paper presents a nine‐switch inverter that can drive two AC motors independently. Recently, as an inverter that can drive them independently, a five‐leg inverter has been proposed. Ten switching devices are used for the five‐leg inverter, whereas only nine are used for the nine‐switch inverter. So, the nine‐switch inverter has the merit that one switching device can be reduced compared to the five‐leg inverter. Moreover, the maximum output voltage of the nine‐switch inverter equals that of the five‐leg inverter. In this work, we propose the structure of the nine‐switch inverter and a modulation method for the same, and validate the nine‐switch inverter by showing simulation results. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

阵面双丝杆举升伺服系统的设计

设计了一种以80C196KC单片机为核心的数字式位置控制器,配以交流伺服放大器而构成阵面举升和仰角控制系统,重点介绍了仰角位置环的设计和同步举升控制中的双丝杆同步控制方法。     

基于光栅信号的步进电机速度控制

在分析步进电机运行特性的基础上 ,讨论了步进电机运行时高速失步和低速波动的原因及其对策 ,研究了转换角和超前角在步进电机速度控制中的作用 ,采用改变光栅反馈脉冲当量角及延时调整转换角的方法进行速度的平稳调节 ,并给出了速度控制方案及其实现     

一种基于LM5025有源钳位的同步整流电路设计

本文设计了一种基于LM5025有源钳位的同步整流电路,介绍了LM5025芯片的功能,说明了有源钳位和同步整流的优点,该电路提高了开关电源的效率,降低了电源自身的损耗。     

Transient State Machine Enabled from the Colliding and Coalescence of a Swarm of Autonomously Running Liquid Metal Motors

Internally triggered motion of an object owns important potential in diverse application areas ranging from micromachines, actuator or sensor, to self‐assembly of superstructures. A new conceptual liquid metal machine style has been presented here: the transient state machine that can work as either a large size robot, partial running elements, or just divide spontaneously running swarm of tiny motors. According to need, the discrete droplet machines as quickly generated through injecting the stream of a large liquid metal machine can combine back again to the original one. Over the process, each tiny machine just keeps its running, colliding, bouncing, or adhesion states until finally assembling into a single machine. Unlike the commonly encountered rigid machines, such transient state system can be reversible in working shapes. Depending on their surface tension, the autonomously traveling droplet motors can experience bouncing and colliding before undergoing total coalescence, arrested coalescence, or total bounce. This finding would help mold unconventional robot in the sense of transient state machine that could automatically transform among different geometries such as a single or swarm, small or large size, assembling and interaction, etc. It refreshes people's basic understandings on machines, liquid metal materials, fluid mechanics, and micromotors.     

Fault detection in transmission networks of power systems

An online fault detection scheme for a sample power system is introduced in this paper. The detection approach is based on the use of a variable structure system called “sliding mode observer”, where information contained in the output measurements is utilized to detect the onset of faults in the transmission network of the sample power system in real time and online. The power system comprises a generating unit connected to an infinite bus through double line transmission network. The common case of a fault occurring on a transmission line is illustrated through simulation studies.     

我国中小型电机制造业市场前景分析

我国将会成为世界电动机,特别是中小电动机的生产制造基地;我国出口电机竞争能力亟待加强,产品开发要与国际接轨,以打入国际市场为主攻方向,从产品质量、外观、性能、安装尺寸、可靠性等方面增强在国际市场的竞争能力;国家优惠政策给电机行业带来了积极的影响     

Feasibility of tapping atmospheric charge as a power source

Mechanisms which generate atmospheric charge are examined in order to estimate the rate of field regeneration. Energy density contained in the atmospheric electric field is examined. Charge-harvesting methods are suggested and a practical use of electrostatic motors examined. Comparisons to projected energy consumption, and comparison to other energy sources are made, and viability of tapping atmospheric charge is assessed.