Researches on End Effects of Permanent Magnet Electromagnetic Launchers

摘要

Brushless DC linear motors have considerable advantages of simpler structure,higher efficiency,higher thrust density and so on.They are well suited for many domains such as electromagnetic launch and launch-assist,but it is inevitable that there exist longitudinal end effects in the mover of the motor caused by longitudinal discontinuities.The serious trouble caused by longitudinal end effects is the thrust ripple.Firstly,by using the method of finite element simulation,this paper studies the distribution of magnetic field and energy in the end region when the mover is in different positions in the range of a polar pitch and discusses the effective methods of reducing the longitudinal end effects.Then the law of the influence of different mover length on the longitudinal end effects has been studied by using analytic methods,and the influences of the mover length and its end geometry shape on the longitudinal end effects have been verified for the test model by using the method of finite element simulation.