聚磁式横向磁通永磁直线电机的变磁导等效磁网络

针对传统横向磁通永磁直线电机空间利用率低的问题,提出一种动子三面墙聚磁式结构的新型横向磁通永磁直线电机,该电机具有高推力密度和高可靠性的特点。首先,介绍横向磁通永磁直线电机(TFPM)的基本结构和工作原理;其次,通过分析在定子和动子不同位置时电机的磁力线分布情况,依次建立等效气隙磁导模型,凸极平面结构等效磁路模型和完整的变磁导等效磁网络模型;最后,将变磁导等效磁网络模型与三维有限元模型的磁链结果进行对比分析,并搭建样机的实验平台,将变磁导等效磁网络模型与有限元模型及样机空载实验的反电势(EMF)计算结果进行对比分析,验证了变磁导等效磁网络模型的结果与有限元分析结果具有良好的一致性,进而证明变磁导等效磁网络模型的正确性。     

横向磁场直线开关磁阻电机的数学建模

为了建立横向磁场直线开关磁阻电机(transverse flux linear switched reluctance motors,TFLSRM)的解析数学模型,首先分析TFLSRM的结构和磁路特点,建立TFLSRM的磁路等效模型,采用直线磁路和变椭圆系数的椭圆形磁路分割法推导等效磁路的气隙磁导解析式,确定以磁导表示的绕组电感和磁链,建立了推力和法向力的数学模型.有限元分析结果验证了所建数学模型的正确性,利用该模型分析了改变次级极宽和气隙长度对电机推力和法向力的影响,半实物仿真实验结果验证了所建模型的有效性.     

动磁式横向磁通直线振荡电机建模分析

针对目前已有动磁式直线振荡电机结构复杂、漏磁较大等问题,提出一种动磁式横向磁通直线振荡电机,其具有动子质量轻,加工难度小,力特性好等优点,适合应用于冰箱压缩机等领域.基于建立的电机等效磁路模型推导出了电磁推力表达式,阐述了该电机电磁推力产生的机理.解析公式显示,电磁力系数与电机结构参数及永磁体材料属性等有关,而与动子位...     

磁路互补型横向磁通切换直线电机电磁推力计算与特性分析

有铁心永磁直线电机由于齿槽、边端效应及电枢电流谐波等,不可避免地会产生较高的电磁推力波动,电磁推力波动直接影响直线电机运行精度和平稳性。该文对具有磁路互补特征的横向磁通切换直线电机展开电磁推力特性研究,通过等效磁路法分析其磁场分布规律,得出该电机次级具有等磁位的电磁特性;基于气隙磁动势-磁导分析方法,揭示互补磁路条件下,该有铁心电机消除齿槽推力波动,实现有铁心电机无齿槽效果的机理;基于该电机磁场分布特征,建立其许-克变换气隙磁场计算模型,提出定位力、电枢绕组磁阻力及永磁推力等电磁推力快速准确的计算方法,获得该电机各电磁推力特性;对样机进行了空载感应电动势和电磁推力的测试实验,对比实验和仿真结果,验证了理论分析模型及计算方法的有效性和准确性。     

基于有限元法的动磁式直线压缩机动态特性

针对动磁式直线压缩机模型样机建立了基于有限元的磁固耦合动态特性分析模型。该模型考虑了磁路的非线性特性、漏磁通及永磁体位置等因素的影响,因此比传统的等效磁路模型更完整。给出了部分分析结果,表明了电机推力、位移和电流之间的相互关系,还给出了几个在不同电压、不同时刻下的矢量磁通密度图,直观地显示了磁场的分布特点及磁路的饱和特性,为直线压缩机的优化设计奠定了基础。     

基于有限元法的动磁式直线压缩机动态特性

针对动磁式直线压缩机模型样机建立了基于有限元的磁固耦合动态特性分析模型。该模型考虑了磁路的非线性特性、漏磁通及永磁体位置等因素的影响,因此比传统的等效磁路模型更完整。给出了部分分析结果,表明了电机推力、位移和电流之间的相互关系,还给出了几个在不同电压、不同时刻下的矢量磁通密度图,直观地显示了磁场的分布特点及磁路的饱和特性,为直线压缩机的优化设计奠定了基础。     

直线力电动机性能分析

分别利用有限元和等效磁路的分析法对直线力电动机特性进行分析,对比分析了电机磁场分布和输出推力特性以及电感和磁链,并与实测结果进行了对比。分析得出了其相关的输出性能并建立其数学模型,为电机优化设计和控制打下基础。     

双定子直线旋转永磁电机特性分析与实验研究

针对现有直线旋转驱动机构结构复杂、体积大、控制精度低等问题,提出一种新型双定子直线旋转永磁电机。该电机由内外定子及一个中间动子构成,能够实现直线、旋转和螺旋运动。分析了该电机的结构特点和运行原理,建立了双定子直线旋转永磁电机的等效磁路模型,推导了转矩和推力的表达式。通过求解所建立的等效磁路模型方程,以计算该电机的空载和负载特性,其计算结果与3D有限元方法一致。设计制作了实验样机,并在所设计的样机上进行实验研究,结果表明所提出的分析理论和方法可以快速、有效地分析双定子直线旋转永磁电机的特性,且所提出的双定子直线旋转永磁电机具有可行性。     

双向交链横向磁通平板型永磁直线同步电机

提出双向交链横向磁通平板型永磁直线同步电机的方案,克服了传统横向磁通永磁电机初级空间利用率不高的缺陷.初级铁心单元加工方便,能够充分利用次级永磁体,有效减小次级永磁体的极间漏磁,增加与绕组相交链的磁链,提高电机的空载感应电动势.文章介绍了电机的结构并阐述了其工作原理,利用磁路法建立了电机的三维等效磁网络模型,推导出了电机的空载主磁通和空载感应电动势表达式,将次级永磁体等效成面电流,获得了推力表达式,通过三维有限元方法计算电机磁场和推力.研制了一台实验样机,测得了空载感应电动势和静态推力.理论分析与实验结果基本吻合,验证了理论分析的有效性.     

圆筒永磁直线同步电机磁场和推力分析

针对轴向磁化圆筒永磁直线同步电机,提出一种基于圆柱坐标的标量磁位分离变量法的磁场解析计算方法,并利用该解析法对无槽电机的气隙磁场分布进行理论分析,得出气隙磁场的轴向和径向磁场分布的解析结果,并解析计算了电机的推力。利用有限元数值计算法对磁场和推力结果进行验证。结果表明,该电机气隙磁场的两种计算方法的结果误差很小,验证了标量磁位分离变量法解析计算气隙磁场及电磁推力的正确性和实用性。给出实验样机的径向磁场分布实验结果,磁密实测值与计算值一致,用负载传感器对电机额定负载的推力进行了实测,验证了样机分析和设计的正确性。     

An efficient piecewise‐linear DC analysis method for general non‐linear circuits

The convergence problems of conventional DC analysis can be partly avoided by using piecewise‐linear analysis. This paper proposes a piecewise‐linear DC analysis method that can efficiently handle arbitrary couplings between non‐linear circuit elements. Piecewise‐linear modelling of the non‐linear circuit elements is automatically performed during simulation, using simplicial subdivisions. The number of linear regions, and thereby iterations, is considerably reduced by combining the common parts of separate simplicial subdivisions. Due to these reasons and since the method is formulated with the commonly used modified nodal approach, it has been possible to implement the method in the general‐purpose circuit simulator APLAC. The correct operation of the method is demonstrated with three examples. Copyright © 1999 John Wiley & Sons, Ltd.     

Analysis of moving magnet linear dc motor with two straight stators

The thrust force of moving magnet-type linear direct current motors (MM-LDM) is analyzed in this study. A moving magnet-type MM-LDM consists of a stator and a carriage. The stator is composed of two stick shaped electromagnetics and the carriage consists of a movable permanent magnet that is located between the two electromagnets. One of the methods for calculating the thrust force of an MM-LDM is to analyze the energy gradient which is determined by the distribution of magnetic flux. However, this method is very difficult when used to calculate the thrust force of this kind of LDM. This type of MM-LDM can be considered to be a transformer in which the magnet of the mover is assumed to be a one-turn coil carrying a large current. The stored energy in the MM-LDM can be obtained by measuring the self-inductance and the mutual-inductance of the equivalent circuit of the MM-LDM. And this energy gradient gives the thrust force. The calculation of the thrust force induced in this motor shows that the mutual inductance has a large influence on the generation of thrust force.     

On the design of high‐efficiency linear induction motors for linear metro

Linear metro with single‐sided linear induction motor (SLIM) propulsion and wheel‐on‐rail support and guidance came into service in April 1990 in Osaka and in December 1991 in Tokyo, and is under construction or planned for Yokohama, Kobe, and Fukuoka. Since the new traffic system is used widely, it is of great importance to decrease its energy consumption. In this paper, the design of the SLIM for the linear metro is formulated as a constrained nonlinear programming problem, and optimum design is carried out to maximize efficiency. Seven parameters are chosen as independent variables: number of poles, pole pitch, stack height, secondary aluminum sheet thickness, overhang length, slot width/slot pitch ratio, and rated slip. The output KW/input KVA ratio, maximum flux density in teeth, temperature rise, primary length, stack height, overhang length, maximum thrust, and vertical force are selected as constraint functions. In the optimization procedure, the performance characteristics are formulated by space harmonic analysis taking account of the end effect, skin effect, and air gap leakage. The accuracy of the formulas is verified against experimental results. Effective ways of increasing efficiency include the addition of a copper reaction plate and minimization of the mechanical clearance. © 2001 Scripta Technica, Electr Eng Jpn, 137(2): 36–43, 2001     

On simplex‐based piecewise‐linear approximations of non‐linear mappings

Simplex‐based piecewise‐linear (PWL) approximations of non‐linear mappings are needed when the robust PWL analysis is used to directly solve non‐linear equations. This paper proposes a straightforward technique for transforming the well‐known approximations into another form. This new form is computationally more efficient, since it preserves the sparse structure of the original Jacobian matrix. Furthermore, this new form of PWL approximation explicitly relates the simplex‐based PWL analysis to the conventional formulation of the Katzenelson algorithm. The proposed transform technique is also extended to treat groupwise‐separable mappings and, finally, non‐separable but sparse mappings that arise in real‐life simulation of large electronic circuits. In this paper, all these (transformed) simplex‐based PWL approximations are compared in terms of their generality and efficiency. The computational efficiency of the PWL approximation that utilizes sparsity is validated with realistic simulations. Copyright © 2005 John Wiley & Sons, Ltd.     

Position control for a linear slider with twin linear drives

In this paper, position control of a linear slider with twin linear drives is considered. Recently, for high‐speed response, several linear motors have been used for linear slider systems. In such a linear slider, if the linear drives are controlled individually, their position responses may undergo vibrational disturbance by interaction with the output of the motors. To control this vibration, this paper presents a dynamic model of a linear slider system which consists of two motion systems decoupled by coordinate transformation, and proposes a feedback controller which is designed for these two decoupled systems. The effectiveness of the proposed method is confirmed by experiments. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 147(4): 68–76, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10291     

A novel compact piecewise‐linear representation

A new compact MAX representation for 2‐D continuous piecewise‐linear (PWL) functions is developed in this paper. The representation is promising since it can be easily generalized into higher dimensions. We also establish the explicit functional form of basis function and demonstrate that the proposed basis function is the elementary ‘building block’ from which a fully general 2‐D PWL function can be constructed. In addition, we reveal the relationship of basis function with minimal degenerate intersection and Hinging Hyperplane, which shows that the MAX model can unify Chua's canonical expression, Li's representation, lattice PWL function and Bremann's Hinging Finding Algorithm into one common theoretical framework. Copyright © 2005 John Wiley & Sons, Ltd.     

Electrical characterization of linear and non‐linear random networks and mixtures

A material composed of a mixture of distinct homogeneous media can be considered as a homogeneous one at a sufficiently large observation scale. The problem of mixture characterization has been exactly solved in case of linear random mixtures, that is, materials for which the various components are isotropic, linear and mixed together as an ensemble of particles having random shapes and positions. In the present work the authors briefly review the linear theory and then consider mixtures of non‐linear media. In particular they give formulas for obtaining their constitutive equations for current density, electrical displacement, and magnetic induction. These relations have been derived by means of heuristic considerations on random networks and they have been verified with simulations obtaining a high degree of accuracy. Copyright © 2003 John Wiley & Sons, Ltd.     

A method for fault diagnosis in linear electronic circuits

A method for fault location and parameter identification in linear AC and DC circuits with limited accessible terminals for excitation and measurement is developed in this paper. Fault location is based on a derived relationship having a general meaning. It requires analyses of the circuit with nominal parameters and distinct excitations as well as measurements of some node voltages in the circuit with perturbed parameters. The fault parameter is identified using a formula obtained on the basis of the Woodbury expression. A decomposition technique is suggested enabling us to apply the method for multiple fault diagnosis. Several numerical examples illustrate the proposed approach and show its effectiveness. Copyright © 2000 John Wiley & Sons, Ltd.     

一种含PV节点的配电网线性潮流计算方法

为了解决线性潮流计算方法无法处理PV节点的问题,提出了一种含PV节点的配电网线性潮流计算方法。所提方法从极坐标的牛顿-拉夫逊法潮流计算的节点功率方程出发,利用配电网的特征对节点功率方程中的非线性项进行线性近似处理,得出一种线性潮流方程。所提方法不仅适用于弱环网络,还克服了大多数线性潮流计算方法无法处理PV节点的缺陷。算例分析表明,以牛顿-拉夫逊法潮流计算结果作为基准,所提方法的最大误差的数量级保持在10~(-4),计算精度与计算效率满足配电系统快速分析的要求。     

直线感应电磁发射器分析与优化

本文对一个两段直线感应电磁发射器进行了分析与优化设计。首先建立了电容驱动的直线感应电磁发射器的数学模型。通过MATLAB编写了系统暂态仿真的仿真程序,给出了系统仿真的流程图。其次比较了直线感应电磁发射器三相电源不同的触发相序对发射性能的影响,得到了最优的触发相序。分析了不同抛体初始位置对出口速度和动能转换效率的影响。最后比较了两段直线感应电磁发射器在第一段电源电压改变时对系统的影响,以及第二段电源电压改变时对系统的影响。从而为下一步的实验提供了理论依据。