A PERMANENT MAGNET AC MACHINE STRUCTURE WITH TRUE FIELD WEAKENING CAPABILITY

ABSTRACT

New doubly salient ac machines in which the field excitation is developed by stationary permanent magnets has recently been undergoing development at the University of Wisconsin. Because of the unique geometry of the stator, these permanent magnets are readily accessible. Therefore, for experimental purposes, simple iron blocks have been used to “short” a large portion of the permanent magnet flux and thus reduce the back emf developed within the machine. However, for practical applications, field weakening schemes involving miniature linear actuators or high torque stepper motors are being explored, as well as machine designs with combined PM and electrical excitation. Preliminary experimental results show that a substantial reduction in the back emf can be readily obtained thus lending credibility to the concept of weakening air gap fields produced by stationary permanent magnets.     

永磁电励均匀混合式直线同步电机设计

本文介绍了一种新型永磁电励均匀混合式直线同步电机,分析了其等效磁路以及推力表达式,阐述了这种电机的设计要点.最后,给出了与普通电励磁直线同步电机的对比试验结果.     

A study of magnetic rotor systems of high-speed electromechanical energy converters

This paper presents the results of a study of magnetic rotor systems of high-speed electromechanical energy converters in the Ansoft Maxwell software package, followed by experimental test. Two magnetic systems were considered: with semicircular and cylindrical permanent magnets. It has been found out that the system with semicircular permanent magnets makes it possible to create an electromechanical energy converter with less dense current in the windings and lower losses at identical weight and dimensions. Moreover, the rotor magnet system with semicircular permanent magnets reduces mechanical stresses in the shrouding rotor shell and, correspondingly, its mechanical expansions during operation. We have considered a case of selecting the number of terminal pairs of high-speed electrical machines with permanent magnets, which required preliminary calculations of losses in the magnetic circuit with aimed parameters for different numbers of terminals.     

Fe-Pt纳米晶永磁合金薄膜研究现状

Fe_Pt纳米微晶永磁薄膜材料由于在高密度磁记录材料领域、微电机械和医用器械领域具有良好的应用前景而受到广泛关注。本文简述了Fe_Pt纳米微晶永磁薄膜的研究现状,介绍了该类永磁材料的结构特点和交换耦合作用机理,重点叙述了有关制备工艺和添加元素对改进其磁性能影响的研究。     

少稀土组合励磁永磁无刷电机设计与分析

基于采用稀土永磁和非稀土永磁组合励磁的磁钢结构,提出了一种并联磁路型的少稀土组合励磁永磁无刷电机。介绍了该电机的拓扑结构及运行原理,并在此基础上结合电机功率尺寸方程和励磁源等效方法,给出了电机的初始设计方法并优化确定了相关的设计参数。利用有限元方法深入分析了电机在空载和额定负载条件下的电磁性能。加工了1台5 k W样机,搭建试验平台进行了相关的试验,结果表明了该电机拓扑结构和优化设计方法的有效性。     

Multipole synchronous machines with fractional q < 1 tooth windings and excitation with permanent magnets

Specific features of multipole synchronous machines with fractional tooth windings and excitation with permanent magnets are considered. A comparison of such machines with motors with standard windings is given. Technical characteristics of manufactured motors are presented. Prospects for application of such motors are shown.     

定子无磁轭模块化轴向永磁电机磁极表面开槽分析

在永磁电机设计中,永磁体(PM)作为励磁磁源,直接影响电机性能。由于定子电流时间谐波和气隙磁场中高次空间谐波的存在,永磁体内产生的涡流损耗不容忽视,极易导致永磁体过热或不可恢复性退磁。本文提出一种减小定子无磁轭模块化轴向永磁电机永磁体涡流损耗的方法,以一台10极、12槽、20k W的轴向永磁电机为例,通过对永磁体表面开槽深度、开槽方式及开槽数目的研究,利用解析法和三维有限元仿真分析不同开槽结构的永磁体涡流损耗,推导出永磁体涡流损耗等解析式。并对比带额定负载时气隙磁通密度,合理选择永磁体表面开槽方式及开槽数目。     

永磁体磁共能的计算方法

虚功法是一种计算电磁力和电磁转矩的常用方法。由于目前对永磁体内的磁共能没有明确的计算方法,使得虚功法在用于含有永磁体的系统时受到一定的限制。本文明确给出了永磁体磁共能的计算方法,并对其物理意义进行了阐述;通过实例计算验证了计算方法的正确性;对永磁体的实际退磁特性进行了考虑,其结果具有普遍的适用性,验证了该计算方法的合理性;并在此基础上分别采用解析法和图解法,对无传导电流时永磁体系统的磁共能进行了计算和分析。该计算方法为虚功法的应用提供了一定的理论基础,可以在一定程度上拓宽虚功法的应用范围。     

异步启动永磁同步电动机永磁体尺寸的估算

永磁体的形状与所选择的磁极结构有关,对于内置式结构,永磁体形状为矩形。异步启动永磁同步电动机的磁路结构通常选用内置串联式结构,两个磁极的永磁体串联。此时,磁路的磁动势为它们的和,而提供磁通的面积为一块永磁体的面积。等于永磁体轴向长度与永磁体宽度的乘积。永磁体的体积则取决于磁场强度H磁密B的乘积。其数值等于永磁体面积与其磁化方向长度的乘积。     

磁力线开关型混合励磁磁阻电机的转矩特性

提出了一种磁力线开关型混合励磁磁阻电机方案。通过电励磁磁势和永磁体磁势的合理配置、匹配与耦合，克服了传统开关磁阻电机励磁损耗大的缺点，电励磁磁势既具有励磁功能，又具有永磁体磁场的控制功能。在阐述该电机结构及工作原理的基础上，通过二维有限元法分析了各种结构参数对电机电磁转矩的影响，并与传统开关磁阻电机进行了对比，对样机的静转矩进行了实验测试。分析结果表明该结构电机具有较高的转矩体积比。     

Excitation magnetic flux losses in acyclic motors with transverse magnetization

A theoretical analysis of the distribution of magnetic excitation flux components caused by permanent magnets in acyclic torquer motors with transverse flux magnetization is presented in the article. Magnetic leakage fluxes were assessed by formulas obtained for the computation of said fluxes. Assessments of their impact and recommendations to reduce leakage fluxes in acyclic motors are also given     

Alnico magnet‐based cost‐efficient design of a permanent magnet reluctance generator for wind energy conversion systems

In this work, a 6/4 permanent magnet reluctance generator (PMRG) with Alnico magnets is designed for small‐scale wind energy conversion systems and its performance is analyzed by finite element analysis. A simple converter topology is proposed to protect the Alnico magnets from demagnetization. Thus, NdFeB magnets, which are predominantly used in electric machines, can be directly replaced by Alnico magnets without changing the size or location. Since Alnico magnets are very cheap, the design cost can be significantly reduced without losing much from the generator performance. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Optimizing the Structural Designs of Starter Generators for Hybrid Powertrain Vehicles

Results of testing starter generators for hybrid powertrain vehicles are given. The objects of investigation were two starter generators with concentric teeth and a 3 × 2 distributed winding. The optimization is performed using a genetic algorithm in the Ansys Maxwell software package. The optimization of selecting a nonmagnetic gap to minimize the negative effect of the armature response to the excitation space of the permanent magnets is considered.     

永磁体磁力与永磁隔振系统固有频率分析

永磁体间的磁力是设计永磁磁悬浮隔振系统的基础.分别用理论计算方法、有限元分析方法以及实验测试方法研究了单对柱形永磁体间的排斥力与磁体间距之间的关系,并分析了所构成的非线性振动系统的固有频率特点,同时也实验测试了多对柱形永磁体间的排斥力与磁体间距之间的关系.结果表明,用理论计算方法和有限元分析方法来计算柱形永磁体的磁力是...     

RUN-UP RESPONSE OF POLYPHASE PERMANENT MAGNET SYNCHRONOUS MOTORS

Abstract

An analysis to predict the transient run-up response of permanent magnet synchronous motors is drived based on the d and q axes model. It is based on the segmental reluctance approach with the addition of permanent magnets in the rotor. The computed simulation of the run-up characteristics are provided for variations in the values of stator resistance and permanent magnet excitation. A series of test results of a 3-phase, 2-pole, 1 hp permanent magnet motor are presented In order to verify the theoretical analysis. Effects of stator resistance on the air gap flux are also recorded experimentally. A reasonably close agreement between the measured and calculated values is obtained     

永磁材料在小电机中的应用

评述了永磁材料在电机中的应用,着重介绍了在小电机中卓有应用前景的稀土永磁、纳米复合永磁、间隙型氮化物稀土永磁等高新永磁材料。     

A three-degrees-of-freedom Maglev system with actuators and permanent magnets

A magnetic suspension system with linear actuators and permanent magnets (instead of electromagnets) has been developed. In this system the bearing forces are controlled by adjusting the air gaps between permanent magnets and the levitated object (a circular disk). This system uses less energy and exhibits none of the overheating of coils typical of systems employing electromagnets. This paper describes a disk suspension system with three degrees of freedom. The system can operate either with a decentralized (distributed) feedback control system or with a centralized (lumped) one. Feedback gain matrices are calculated for each type of control system. The performances of the two types of control systems are compared by numerical simulations and experiment. This work is part of an effort to develop a magnetic levitation conveyer system.     

Sm2Co17稀土永磁材料的研究概况

随着现代工业的发展,对永磁体的要求也越来越高,既要求磁性能优良,又要求稳定性好,可靠性高.目前,对Sm2Co17稀土永磁材料的研究主要体现在高温永磁体、高稳定性永磁体和成型工艺等方面.影响Sm2Co17磁体性能的因素较多,其中比较重要的因素是磁体的显微组织、时效处理及合金的化学成分等.     

A novel permanent magnet motor with doubly salient structure

A new type of doubly salient machine is presented in which the field excitation is provided by nonrotating permanent magnets. This doubly salient permanent magnet (DSPM) motor is shown to be kindred to square waveform permanent magnet brushless DC motors. Linear and nonlinear analyses are made to investigate the characteristics of this new type of PM motor. A prototype DSPM motor is designed and comparisons made between this new type of motor and the induction motor. It is shown that by fully exploiting modern high energy PM material and the doubly salient structure, the DSPM motor can offer superior performance over existing motors in terms of efficiency, torque density, torque-to-current ratio, torque-to-inertia ratio etc., while retaining a simple structure amenable to automated manufacture     

Power supply systems for rapid cycling synchrotron

JAEA and KEK are jointly constructing the high‐intensity proton accelerator project J‐PARC. Its main accelerator is a 3‐GeV rapid cycling synchrotron (RCS). Two types of resonant excitation systems, parallel and cascade, are introduced to excite DC biased 25‐Hz AC currents through its main magnets. The parallel excitation is adopted for the dipole magnet power supply system, and the cascade excitations are adopted for the seven family quadrupole magnets system. In this paper, the two systems are investigated and analyzed, and an explanation is given as to why the different types are adopted in each system. The authors believe that such hybrid exciting systems are most suitable for a high‐power RCS. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(1): 49–60, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20535