Design Of Hybrid Excitation Flux Switching Linear Magnetic Suspension Motor

In this paper,the hybrid excitation flux switching linear magnetic suspension motor for maglev train traction system is studied.The characteristics of the motor is that the permanent magnet,excitation winding and armature winding are all located on the short primary mover,while the long secondary is only composed of the magnetic core,so the structure of the motor is simplified.The armature winding,the excitation winding and the permanent magnet are not required to be laid along the long track,thereby greatly reducing the system cost.Because of the use of high-performance permanent magnets,the motor has higher efficiency and power density.The main research work of this paper is as follows:(1)A hybrid excitation flux switching linear magnetic suspension motor for rail transit is proposed.In this paper,the operation mechanism of hybrid excitation flux-switched linear magnetic suspension motor is studied,and the topology and operation principle of hybrid excitation flux switched linear magnetic suspension motor are analyzed in detail,including the principle of flux switching,electromagnetic thrust generation and levitation force generation.The mathematical models of hybrid excitation flux switching linear magnetic suspension motor and electromagnetic thrust and suspension force are derived.(2)Hybrid excitation magnetic flux switching linear magnetic suspension motor is designed.According to the design methods of permanent magnetic flux switching linear motors and hybrid excitation linear magnetic motors,the general design methods of hybrid excitation magnetic flux switching linear magnetic suspension motors are obtained.First,from the perspective of output power,the size of the motor is calculated,the appropriate pole distance ratio is selected,and then the size of the corresponding part of the motor and stator is obtained.The appropriate permanent magnet material is selected and the size of the permanent magnet is calculated,and the armature winding parameters that meet the requirements are obtained by adjusting the motor design steps.(3)Finite element analysis of hybrid excitation flux switching linear magnetic suspension motor is carried out.A two-dimensional finite element model of hybrid excitation flux-switched linear magnetic suspension motor is established,and the magnetic field distribution of the motor under no-load and load conditions is obtained.The harmonic content of air gap magnetic density waveform is analyzed to verify the rationality of motor design Through simulation experiments,the effects of different air gap length,excitation current,armature current and permanent magnet thickness on the main performance indexes of the motor,such as electromagnetic thrust and suspension force,are compared,which provides theoretical basis for the control in the field of rail transit.