The Use of Permanent-Magnet Machines in Ship Electrical Systems

Ships are autonomous objects in which the capacity of the power plant and volume of available space are limited. Permanent-magnet machines with the maximum coefficient of efficiency and minimum mass and dimensions can be widely used on the ships, first of all, in high-power ship systems—generator sets, propulsion systems, and thrusters. However, there is a danger of fire during interturn faults in the stator winding in permanent-magnet machines. If such a fault occurs in the standard operating mode, then, when the rotor turns by inertia or, under the action of slowing water flow, moves to the propeller in the closed circuit of the stator winding, an electromotive force will be induced since the magnetic field of the rotor remains. This electromotive force will produce a current in the closed circuit, and a large amount of heat will be released in the winding-fault area, which can lead to a fire on the ship. This article considers a method of “damping” of the magnetic field in the rotor in an emergency situation. In this method, the magnetic system of the rotor is made of two parts, one of which is fixed on the rotor, while the second is installed on the rotary sleeve. In the normal condition of the machines, the angular positions of the analogous poles fixed on the rotor and installed on the rotary sleeve coincide. In the emergency condition of the machine, the sleeve turns so that the angular positions of the opposite poles of the rotor and sleeve coincide. As a result, the induction of the magnetic field in the gap and the electromotive force in the stator windings in the emergency condition of the machine will be close to zero.     

A Computer-Interfaced Electrical Machines Laboratory

A relatively inexpensive computer interface with an electric machines laboratory is described. This interface permits a number of experiments which could not be performed otherwise. Three such experiments are described in this paper: an interactive phasor diagram of the synchronous machine model, the dynamic buildup of speed of a dc motor, and the electomechanical oscillation of a synchronous motor.     

Analysis of Instability in Electrical Machines

While there exist numerous studies of electromechanical instabilities of specific electrical machines in constant or periodic speed operation, a broader perspective is not commonly offered. In contrast, a general machine model is used here to present essential and common features of these stability analyses. Fundamental issues are illuminated at this level of generality before specialization to the details of a specific machine. To begin, Park-transformable machines in constant-speed operation are considered. The local dynamics of these machines are linear and time-invariant. For such machines it is shown that instability may be analyzed in a useful way via systematically obtained reduced-order models. This is illustrated by significantly expanding an earlier study of a hybrid stepping motor. The more general situation in which the linearized models that govern local behavior are periodically varying is considered next. Classical Floquet theory is reviewed to provide the tools needed for stability analysis in this situation.     

挖掘机电气控制系统设计

正铲挖掘机是一种矿山专用机械，介绍了这种设备基本运行工况及对电气控制系统的一般要求，详细叙述了回旋，提升，推压系统的主控制电路，该电路结构简单工作可靠，给出了系统具体控制线路，对原理图中各部分的工作原理，主要元件的功能也作了详尽介绍，该系统具有良好的控制特性，挖掘机在矿山现场运行多年，其性能满足实际要求。     

Radio Frequency Diagnostic Monitoring of Electrical Machines

RF diagnostic monitoring should make it possible to improve machine maintenance schedules and achieve more time in service.     

现代化拉线机中连续退火的电控技术

本文剖析了连续退火的电控技术中退火电压的自动跟踪控制原理,介绍了引进现代化拉线机中连续退火装置的设计思想、系统组成及关键线路的原理。指出了国产设备连续退火装置目前存在的主要技术问题,对国产拉线机连续退火装置设计和技术改造,具有重要的参考价值。     

现代汽车电机的发展状况

根据现代汽车电机的广泛应用，详细地介绍了汽车交流发电机、起动机、空调电机和门窗升降器电动机的功能和结构，并指出其未来的发展趋势。     

基于最小二乘支持向量机的复杂气象条件下绝缘子等值附盐密度的预测

以"光传感器输变电设备盐密在线监测系统"提供的数据为依据,建立了一种基于最小二乘支持向量机的智能预测模型,该模型以温度(T)、相对湿度(H)、风速(Wv)、气压(P)、雨量(R)等5个变量为输入参数,等值附盐密度为输出参数,用二次损失函数取代支持向量机中的不敏感损失函数,将不等式约束条件变为等式约束.从而将二次规划问题转变为线性方程组的求解,用最小二乘法实现了支持向量机算法.用网格搜索法对最小二乘支持向量机最优参数进行自动选取,提高了预测的快速性和准确性.仿真结果表明,与BP神经网络预测的结果相比.该模型预测的等值附盐密度更接近实测结果.本文的方法为电网污区分布图的计算提供了一条新的思路.     

Specifying and Designing Flexible Shaft Electrical Machines

Recent developments relating to the undestanding, analysis, and measurement of vibratory motiohs, forces, and instabilities of rotating systems and their bearing support structures are now becoming available to the designers of systems involving electrical machines and their component suppliers. The status of the more pertinent of these developments and their applicability to such systems is reviewed with special considerations to those involving flexible shaft machines.     

电机优化设计技术发展情况

在分析电机优化设计技术文献的基础上，总结了国内在电机传统优化设计方面的特点，几种主要的新型算法及其在电机设计中的应用，电磁场逆问题的优化设计，以及电机优化设计技术的发展动向；并对该领域未来的发展趋势作了展望。     

电机优化设计技术发展情况

在分析电机优化设计技术文献的基础上,总结了国内在电机传统优化设计方面的特点,几种主要的新型算法及其在电机设计中的应用,电磁场逆问题的优化设计,以及电机优化设计技术的发展动向;并对该领域未来的发展趋势作了展望。     

电网故障下双馈风力发电机暂态电流分析

通过分析双馈风力发电机的暂态电气关系,推导转子暂态电流的时域表达式;并通过对比不同跌落系数下的暂态电流,分析了转子暂态电流的变化规律;并对电网三相短路故障下双馈风力发电机的暂态响应进行仿真,验证了暂态电流表达式的正确性。     

用对偶有限元法计算电机参数的研究

对对偶有限元法在电磁场中应用的有关理论问题进行了分析和讨论，并将该方法应用于涡流场的参数计算，导出了二维涡流场中通过向量磁位Ａ计算电磁参数的对偶有限元离散格式。对一些实例进行了计算。计算结果表明，用这种方法求取电磁参数具有计算量小，精度高的特点。计算结果可以作为设计时的参考。     

多相电机的绕组设计

介绍多相电机绕组的特点及其对电机设计的影响。     

旋转电机的电磁兼容性(EMC)要求及其试验方法介绍

本文介绍了旋转电机国家标准中涉及的电磁兼容性要求和试验方法.     

微特电机产业发展概述

概述厂我国微特电机产业发展的两个阶段，提出了微特电机生产企业在技术发展上要注重的几个方面。     

状态变量法在电机优化设计中的应用

提出了在电机优化设计中引入状态变量的方法，并建立了一种优化设计数学模型，给出了一台单相电容电机实例的计算过程和结果。从计算结果看，此方法是有效的。     

永磁电机中永磁体数学模型的分析

永磁体的数学模型的确定是永磁电机磁场计算中的关键。文中从电磁场基本理论出发,导出了永磁体在任意复杂形状下,不同磁化方向（平行磁化、径向磁化、圆周方向磁化）时永磁体边界上等效电流的计算方法,为永磁电机电磁场分析计算奠定了基础。     

电机绝缘技术发展历程与方向

简要介绍了电机绝缘技术的几个基本概念及主要研究内容,回顾了电机技术选用的绝缘材料由天然材料到合成聚合物的发展及回归环保的历程,以及高压交流电机主绝缘历年发展情况和现代高压交流电机绝缘技术的发展方向.     

井下涡轮电机参数精密检测系统设计

井下涡轮电机是旋转导向钻井系统的电源、控制执行器和下传通信信号检测器,检测其电流、电压是实现井下自动控制和下传通信的关键。针对旋转导向钻井系统对涡轮电机参数的精密检测要求,检测系统采用Rogowski互感线圈进行检测,信号经过放大、精密整流、A/D转换后送给井下控制器。给出了系统的电路设计,提出了温度补偿办法。该检测系统已应用于某井下旋转导向钻井系统,效果良好。