Multipolar permanent-magnet synchronous generators intended for wind power plants

The analytical method of calculating two-dimensional magnetic fields in the active section of permanent-magnet synchronous electrical rotating machines, as applied to their use in the wind energy industry, has been developed. The analytical relationships for calculating distribution of two-dimensional magnetic fields and determining output parameters with due regard for geometry of the active section, the number of pairs of poles, and magnetic characteristics of materials have been obtained. The criteria dependences needed for calculating the electromotive force and main inductive reactance of permanent-magnet synchronous electric machines, with consideration for the geometry of a machine and electrophysical properties of materials being used, have been derived. The procedure of evaluating parameters of permanent-magnet synchronous generators for large-size wind power plants is presented.     

应用数值解析结合法计算旋转电机磁场

采用数值解析结合法计算旋转电机的二维磁场,推导出计及电机极对数时的气隙磁场的解析表达式,并用矢量磁位相等的交界条件连接磁场的数值和解析方程。以一台永磁无刷电机的磁场计算为例,通过与有限元法的计算结果比较,验证了本文方法的正确性和有效性。     

泵站电机的绝缘故障与绝缘寿命

在泵站,电机的绝缘故障是一个突出的问题。本文根据对湖北省15个市县29个泵站200余台电机的大量调查与部分电机的现场测试,研究了这些电机投运的气候特点与故障时间的关系;分析了故障原因及规律性;提出了部分电机在运行中出现的问题;列举了不同投运绝缘电阻对绝缘的不同影响;并结合泵站的运行特点,阐明了对泵站电机绝缘寿命评定的见解。     

Developing measuring inductance strategies on a direct current machine using a DC source with magnetic saturation

This article describes a novel measuring inductance strategy on direct current (DC) machines. Measuring self‐inductance and mutual‐inductance in rotating machines is always a very challenging task over a few decades. A significant challenge in modeling electric machines is to obtain their variables and parameters as accurate as possible. The method developed in this paper using a DC source for measuring the inductance in a DC machine overcomes some problems associated with traditional methods by using an alternating current source. In particular, it enables the field winding to carry its rated DC. This approach has demonstrated the feasibility of taking measurements for inductance in a DC machine and providing its field current that is sufficient to lead magnetic saturation, such that the flux can be kept the same as the supplied flux to the running DC machine. The proposed method for measuring both self‐inductance and mutual inductance of the DC machine armature winding coils has played a main role in modeling DC machines under a wide range of operating conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

The improvement of the electrical insulation of high voltage electrical machines

Comparative parameters are presented for the electrical insulation systems of high voltage electric machines. Composite insulation materials produced by different manufacturers are studied. The influence of the structure and composition of electrical insulation materials on the main operation parameters (electric strength, dielectric losses, the mechanical characteristics, and resistance to thermal cycling) of the insulation systems of electric machines is shown.     

A research trend of electric machines with development of finite element analysis

Finite element analysis (FEA) has rapidly developed in the past three decades. In case of the magnetic field analysis, many researchers have proposed different electric machines by using FEA in order to achieve high efficiency, high torque density, low torque ripple, and so on. For further development of electric machines, this paper presents a literature survey on the state‐of‐the‐art research trends of the electric machine related to FEA in the last 3 years. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Unbalanced Magnetic Forces in Permanent-Magnet Brushless Machines With Diametrically Asymmetric Phase Windings

A general analytical model, formulated in 2-D polar coordinates, is developed to predict the unbalanced magnetic force, which results in permanent-magnet brushless ac and dc machines having a diametrically asymmetric disposition of slots and phase windings. It is shown that the unbalanced magnetic force can be significant in machines having a fractional ratio of slot number to pole number, particularly when the electric loading is high. The developed model is validated by finite-element calculations on 9-slot/8-pole and 3-slot/2-pole machines. In addition, the unbalanced magnetic force has been measured on a prototype 3-slot/2-pole machine and shown to be in excellent agreement with predicted results.     

交流励磁电机发展前景

随着电力电子技术与数字控制技术的发展,交流励磁电机应运而生。它有优于同步电机的性能。文章分析了交流励磁电机在不同工业领域的发展前景及所要解决的问题。     

交流旋转机械的状态监测

在综述了各种交流旋转机械的状态监测方法后,对小波变换新技术进行了介绍,并通过小波变换对暂态非平稳信号的分析,阐明了小波变换在分析暂态信号方面,比传统的Ｆｏｕｒｉｅｒ变换更具优越性。交流旋转机械随着运行状态的劣化,会产生一些暂态信号。因此,利用小波变换来监测交流旋转机械的状态,具有良好的应用前景。     

Calculation of ventilation for winded electric machines using three-dimensional numerical simulation of airflow current

FlowVision software is employed to calculate the capacity and demand of built-in fans for electric motors produced by the VEMZ public corporation. Experience in such usage is summarized. The results obtained can be used for the modification of existing empirical methods of calculations for built-in fans in electric machines. The technique of making computational experiments using FlowVision software is developed. This software can be used for the calculations of various ventilation systems in electric machines.     

近极槽数表贴式永磁同步电机齿顶漏磁分析与计算

近极槽数表贴式永磁同步电机的齿顶漏磁比较大,凭传统经验选取齿顶漏磁系数,再利用有限元软件仿真的方法延长了电机设计周期,即齿顶漏磁的快速、准确计算十分必要。根据半单元电机内每个齿的齿顶漏磁各自不同的特点,提出了平均每极齿顶漏磁的计算方法。将半单元电机内的所有齿的齿顶漏磁规算到每个磁极下,推导出了平均每极齿顶漏磁和齿顶漏磁系数的解析表达式。在此基础上进一步研究了电机极数和极弧系数的变化对齿顶漏磁系数的影响。平均每极齿顶漏磁解析法计算结果与有限元软件仿真结果一致,验证了平均每极齿顶漏磁计算方法的正确性和准确性。     

Simulating the operation of auxiliary machines of a 2(3)ES5K locomotive

Auxiliary machines of electric trains provide the operation of traction motors and electrical and pneumatic equipment. The main condition of safe operation of the asynchronous electric drive of auxiliary machines is the maintenance of the operation mode of the electric drive in terms of the basic technical data, according to which NVA-55 electric drives are matched by nominal operation (long-term) mode S1. The effect of supply voltage on the operation of locomotive auxiliary machines is considered. Auxiliary machines are used under poor conditions on alternating current electric trains. Disbalance of the motor currents occurs even at nominal voltage of the overhead contact system and operable phase-shifting device. In operation, the voltage on the contact wire line is not constant and the equipment modes can be inconsistent with the nominal one, which leads to a significant number of failures of auxiliary equipment. This makes it necessary for the microprocessor control system to use the controlled auxiliary electric drive. An individual autonomous inverter with fully balanced sinusoidal output voltage allows one to increase the reliability of the induction motor drive, while the proportional control of the blower motor reduces the power consumption.     

旋转电机绕组磁链的三维有限元分析

针对非正弦电压供电的旋转电机稳态或动态性能仿真,提出了一种基于三维有限元分析和网格重构的绕组磁链和端部漏电感的计算方法,根据所提出的方法,计算了一种三相12/8极开关磁阻电机的绕组端部磁链,并给出了端部漏电感随转子位置和邻近绕组电流变化的曲线族。该计算方法也可用于旋转电机或其它电磁装置的三维磁链计算。具体算例说明了考虑端部漏磁场效应的条件和必要性。     

盘式电机在我国的发展及其展望

介绍了近二十年来盘式电机在我国的发展．主要有定、转子铁芯的生产、磁场的研究、电机的分类及展望,对我国盘式电机的更大发展有一定的现实意义．     

Design and analysis of a mass spectrometer with superimposed magnetic and rotating electric fields

We planned to develop a small and inexpensive measurement device for determination of molecular concentration. The analysis process operates by superimposing a rotating electric field on a magnetic field. When the strength and frequency of the rotating electric field and the mass and speed of the ion are predetermined, the circular radius of the ion's trajectory is fixed. We designed a computer program to simulate ion movement in the electric field and magnetic field. It is possible to calculate the circular movement of the ion in the rotating electric field, and then calculate the circular movement in the superimposed state of the rotating electric field and magnetic field. The magnitude of the mass spectrometer conventionally determines resolution ability. Our definition of resolution is the fraction equal to the distance of separation divided by the distance of the attainment point. The resolution increases gradually at first, and then rises suddenly and dramatically to over 20 times the resolution of that of a spectrometer which does not use a superimposed field. We believe that the theory of ion movement in the rotating electric field and magnetic field could lead to the development of a small and inexpensive analysis machine. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(1): 15–26, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10113     

Developing a combined method for analysis of electric machines

A combined method for the simulation of magnetic fields, characteristics, and processes in electric machines (EMs) is developed that is based on a new type of equivalent electromagnetic circuit. The new method combines calculations of the magnetic fields in local zones of an EM with numerical simulation of the discrete structure of that EM. An approach to the simulation of the 3D magnetic field of an EM whose core is characterized by axial nonuniformity is proposed     

双馈风力发电系统中有功无功解耦控制技术的仿真研究

介绍了变速恒频风力发电的基本原理,给出了双馈型变速恒频风力发电机在两相同步旋转坐标系下的数学模型.利用定子磁链定向的矢量控制方法将同步坐标系下的双馈电机数学模型简化后得到矢量控制系统的模型;矢量控制模型与双馈电机模型一起构成闭环控制系统.利用Matlab软件建立了系统的仿真模型并给出了仿真结果,验证了定子磁链定向矢量控制策略的正确性,保证了有功功率、无功功率独立解耦控制的目的.     

超导旋转电机——发电机和电动机的研究现状

简要介绍了超导发电机和超导电动机的基本特性及其在电力系统中应用的优越性能,阐述了这两种旋转电机的发展现状和未来研究方向。     

超导旋转电机——发电机和电动机的研究现状

简要介绍了超导发电机和超导电动机的基本特性及其在电力系统中应用的优越性能,阐述了这两种旋转电机的发展现状和未来研究方向。     

A brushless electric motor with a transverse magnetic flux and disk rotor

Brushless permanent magnet machines (BPMMs) have a greater efficiency and smaller overall dimensions than do other types of machines and are widely used in electric drives for various purposes. Two types of BPMMs are used in practice: BPMMs with a classical double-layer-distributed stator winding and BPMMs with a toothed-step stator winding. There exists another type of BPMM with a transverse magnetic flux (transverse flux motors, TFMs) which is being actively studied. In TFM electric motors, the magnetic lines of fluxes of the poles of rotor end perpendicular to the direction of rotor rotation. Stator windings in these machines are fabricated as rings coaxial with rotor, and the magnetic circuit of stator consists of separate fragments. Specialists assert electric TFMs have a higher specific power—the ratio between the output power and the mass of the machine—than the electric motors of other type. They are of interest, first and foremost, for electric drives without reducing gears. In most TFM, only a half of the poles of rotor are magnetically connected with circular phases of stator. In this work, the TFM design with disk rotor is described, in which the magnetic flux of all poles of rotor is coupled to the circular phases of stator. The stator magnetic circuit in this machine consists of P-like elements, and alternation of polarity of these elements is provided due to the change of their position. As a result, the magnetic flux coupled to the circular phase increases doubles, as do the machine torque and power. Some results of modeling of a three-phase electric motor are presented. The results were obtained using the Ansys Maxwell computer code, including a graph of the change of torque on the shaft of a machine under rotation of the rotor under conditions of sinusoidal currents in phases.