针对工程中对高速磁悬浮列车涡流制动系统(Eddy Current Braking System,ECBS)电磁特性研究不够深入的问题,提出电磁模型并建立制动力与列车运行速度、磁极对数、励磁电流、次级板厚度、励磁线圈匝数、铁芯齿槽结构等参数之间的关系.首先,基于等效电流层法将涡流制动系统分为3个求解区域,并且计算各求解区域内的磁场分布表达式.其次,建立感应电流密度分布模型,计算趋肤效应对次级板材料电导率的影响,并对其进行参数修正.再次,引入次级板材料电导率修正系数,利用各求解区域上的边界条件计算次级板与气隙交界面处的磁通密度表达式.最后,根据麦克斯韦应力张量法推导出制动力表达式,根据磁悬浮列车涡流制动系统的参数搭建三维有限元仿真模型.研究结果表明:在对涡流制动力随速度、励磁电流和次级板厚度3种参数变化情况下的曲线分析可知,解析计算和有限元仿真结果之间的平均相对误差在10%以内,验证了数学解析模型的有效性;制动力随列车运行速度增加,先增大后减小,在速度为50 km/h时出现峰值;制动力随励磁电流、励磁线圈匝数等参数增加而增大;制动力随磁极极距、次级板厚度等参数增加,先增大后趋于平稳;制动力随初级槽深增加先保持平稳,当通过临界点后迅速减小.
Research on the electromagnetic characteristics of the high-speed magnetic levitation eddy current braking system
In response to the insufficient research on the electromagnetic characteristics of the Eddy Current Braking System(ECBS)for high-speed maglev trains in engineering,an electromagnetic model is proposed.The relationship between braking force and parameters such as train operational speed,number of magnetic poles,excitation current,secondary plate thickness,number of turns in excitation coil,and structure of iron core cogging is established.First,the ECBS is divided into three solution regions based on the equivalent current layer method,and the magnetic field distribution ex-pressions for each region is calculated.Second,a model for the distribution of induced current density is developed,accounting for the skin effect's impact on the conductivity of the secondary plate mate-rial,and parameter corrections are made.The conductivity correction coefficient for the secondary plate material is then introduced,and the magnetic flux density expression at the interface between the secondary plate and the air gap is calculated using the boundary conditions in each solution region.Fi-nally,using the Maxwell stress tensor method,the braking force expression is derived,and a three-dimensional finite element simulation model is built based on the parameters of the ECBS for the mag-lev train.The results show that,in the analysis of braking force variations with respect to speed,exci-tation current,and secondary plate thickness,the average relative error between the analytical calcula-tions and finite element simulation results is within 10%,validating the mathematical model's effec-tiveness.The braking force first increases and then decreases with the increase of train speed,peaking at 50 km/h.It increases with the rise in excitation current,excitation coil turns,and other parameters.The braking force first increases and then stabilizes as magnetic pole pitch,secondary plate thickness,and other parameters increase.The braking force remains stable with increasing primary groove depth and decreases rapidly after surpassing the critical point.
eddy current brakingequivalent current layer methodfinite element methodelectromag-netic performance
万方数据
维普
