Study On The Optimal Design Method Of Electromagnetic Characteristics Of Flux Switching Permanent Magnet Linear Motor

Using a rotary motor and ball screw to realize high speed and high precision linear motion is very difficult,but it can be very good qualified for a linear motor.The flux switching permanent magnet linear motor,which is the research object of this paper,not only has the advantages of high power density,simple secondary structure and strong robustness,but also can solve the problem of waste materials that exists in the application of the traditional permanent magnet linear motor in the long stroke feed system.But the end effect causes thrust fluctuation.The general way to weaken the end effect is the introduction of auxiliary teeth,and this method is complex and high time cost,so it is important to search a simple and effective way to weaken the end effect.Besides the traditional U type core due to the strong repulsion between adjacent permanent magnets and multi modular design can bring difficulties in manufacturing and assembly,so using a new shape core design is very necessary.This thesis first introduces the research status of the structure optimization and analysis method of the flux switching permanent magnet linear motor in the domestic and foreign literatures.A new way to weaken the end effect is studied deeply,which only needs to optimize the width of the permanent magnets at the end.The primary iron with magnetic bridge is adopted,making the primary core a whole and the processing and assembly easier.Complementary magnetic circuit design is adopted and the harmonics of the back electromotive force are weakened.Secondly,the working principle of flux switching permanent magnet linear motor is explained and the average thrust equation is derived.The initial motor parameters are obtained.The equivalent magnetic circuit model of the motor is established,and finite element method is used to verify the correctness of the model under the condition of different air gap lengths and different core heights.The finite element model of the motor is established and the optimal width of permanent magnets at the end is gotten by the single parameter finite element method.Through the finite element method and response surface method combined,the optimal values of permanent magnet width,primary tooth width and secondary tooth width are obtained,which not only meets the design requirements of electromagnetic properties,but also greatly reduces the permanent magnet usage amount.Finally,the structure design and assembly of the prototype are carried out,and the no-load and load experiment platforms are built respectively.The waveforms of the three-phase no-load back electromotive force at different speeds and electromagnetic thrust under different load conditions are measured.Compared with the simulation results of the finite element,the correctness of the study on the optimal design method of the electromagnetic characteristics of the flux switching permanent magnet linear motor is verified.