不同槽配合格栅型直线感应电机电磁特性研究

吕刚 张贤

Abstract：In order to weaken the transverse end effect and increase the electromagnetic thrust， the ladder-type secondary was proposed as a new topology of linear motors. Based on the theory of electromagnetic field， the finite element analysis method was used to establish the finite element model of linear induction motor with two types of ladder-type secondary. In the transient field， the variation of the thrust and normal force amplitude and the fluctuation of force of linear induction motors with the two types of ladder-type secondary under different slot combinations were analyzed， besides， the eddy current distribution and the transverse air gap magnetic field distribution in ladder-type secondary and flat secondary were analyzed and compared. Considering the influence of the normal force， the net thrust characteristics of linear motor with the ladder-type secondaries were calculated under suitable slot combination，in the meantime the variation curves of the electromagnetic thrust and the normal force of two types of ladder-type secondary with the velocity were obtained. Through the above finite element analysis， it provides a theoretical reference for the optimization design of linear induction motor.

Keywords：linear induction motor; ladder-type secondary; the finite element analysis ; the transverse air gap magnetic field; thrust

0 引 言

随着直线电机轮轨车辆以及中低速磁悬浮列车等城市轨道交通工具的快速发展，其核心部件——直线感应电机的应用越来越广泛，相比传统轮轨机车采用的旋转电机，直线感应电机具有噪声小，爬坡能力强，工程造价低等众多优势[1]。应用于低速磁浮列车的直线感应电机不仅产生驱动列车的推力，还产生影响悬浮系统的法向力[2]。然而采用直线电机的城轨交通中也存在固有的缺点，因为次级感应板在直线电机车辆系统中沿线路铺设，成本较大;同时整体感应板的使用以及较大的气隙导致直线感应牵引电机的效率和功率因数较低。本文主要研究在控制制造成本的前提下，通过格栅型次级感应板来提升直线感应电机的各项电磁性能，主要考查对象为笼型格栅次级和梯型格栅次级。

文献[3]提出“等效电磁极距”的概念考虑电机的纵向端部效应，给出不同极数时极距的修正系数。文献[4]对次级复合感应板的单边直线感应电机气隙磁密的分析，得到了适合解耦控制用的直线感应电机动态数学模型和推力和法向力的解析表达式。文献[5-7]提出笼型次级单边直线感应电机结构，可以提高电机推力等性能。文献[8]对5种不同的笼型次级进行了二维有限元分析，比较了次级不同铝槽型直线感应电机的推力、法向力特性。文献[9]提出了一种直线电机轨道交通用栅形直线电机次级装置，包括导磁铁心、导电体以及安装支架，直观的介绍了笼型次级结构。……