电磁弹射过程中涡流引入阻力的分析

Analysis of Eddy Current Force in Electromagnetic Aircraft Launch System

永磁直线电机能够满足电磁弹射系统短距内高加速与快制动的应用要求,但是永磁直线电机的快速运动可能引入明显的涡流效应,在电机加速度段,涡流效应引入涡流阻力,削弱了系统的弹射能力,另一方面,在电机的制动段,涡流效应引入的阻力可以帮助系统实现快速制动。针对电磁弹射系统所采用的定子开槽、集中绕组、动磁式永磁直线电机,仿真分析了动子加速过程中铝支撑套引入的涡流阻力的特性,提出用定子铁心半闭槽结构和空心支撑套结构等措施降低这种涡流阻力,验证了措施的有效性;在制动段采用实心定子铁心结构来增强涡流制动力以实现快速制动,建立了涡流损耗的简化多项式,仿真结果表明采用涡流制动、反接制动混合制动的方式可以有效提升弹射平台的制动性能。

Permanent magnet linear motors are fit for the application of quick acceleration and braking within short distance in electromagnetic aircraft launch systems,but eddy current is likely to be induced by its quick moving.In the acceleration stage,the resistance force deduced by the eddy current can reduce the launch ability of system.On the other side,the force deduced by the eddy current can improve the braking ability in brake stage.This study analyzed the eddy current force in a kind of linear motor with open slot,concentrated winding,and moving permanent magnet.In the acceleration area,the eddy current resistance force deduced by the aluminum sleeve of the permanent magnet mover was analyzed.A method to weaken this resistance force by half open slot and hollow sleeve structure was proposed,and the feasibility was proven.In brake area,a solid stator structure was proposed to take the place of a laminated stator structure,which can increase the eddy current braking force and shorten the braking time.A simplified function has also been formulated for the eddy loss.Simulation results indicate that a hybrid braking technique combining eddy current braking and plug braking can improve the braking ability efficiently.