初级横向偏移时直线电机的特性分析

Analysis of characteristics of linear motor with primary lateral offset

基于直线电机初、次级发生横向相对偏移时,会造成气隙磁密、涡流、力等性能参数的畸变问题,对直线感应电机进行了研究,建立了直线感应电机三维有限元模型.为了分析横向偏移的影响,利用3D有限元法对电机内的电磁场和次级铝板上的涡流分布进行了精确计算,得到了磁场、涡流和力在铝板表面上的分布,从而得出畸变程度会随着偏移量的增加而逐渐加剧的结论.为了量化畸变程度,提出了电流密度纵向分量畸变率、磁密法向分量畸变率和侧向力畸变率,并对各畸变量进行了计算分析,最后定性分析了发生横向偏移时,电机产生纵向转矩的原因.仿真结果表明:上述物理量的畸变程度随偏移量的变化近似成线性增加.

Since the problem of lateral offset of primary and secondary linear motor will cause distortion of air-gap magnetic flux density,eddy current and force,the linear induction motor is studied and a three dimensional finite element model of linear induction motor is established.In order to analyze the influence of lateral offset,the distribution of eddy current in secondary aluminum and electromagnetic field in the motor are accurately calculated by the finite element method,so as to obtain the distribution of magnetic field,eddy current and stress on the plate surface.It is concluded that the degree of distortion increses greatly while offset increases.In order to quantify the degree of distortion,the distortion rate of longitudinal component of current density,the distortion rate of normal component of magnetic density and that of lateral force are put forward,and these rates are calculated and analyzed.Finally,aqualitative analysis is conducted on the reason why longitudinal torque will appear on the motor when the lateral offset occurs.Simulation results show that the degree of distortion of the above variables increases approximately linearly with the change of offset.