Design And Analysis Of A Modular Fault-tolerant Permanent-magnet Vernier Linear Machine

With the rapid economic development,people's demand for the traffic environment has gradually increased.At present,China has entered the era of rapid development of unban rail transit construction,the future development of urban rail transit is one of the direction of the establishment of green urban rail transit system.The linear permanent-magnet(PM)motor has received widespread attention due to the merits of high power density and efficiency.Among various kinds of linear PM motor,the primary-PM motor is very suit for long stroke application due to its lower engineering costs.This is because the PMs and armature windings are set on the short mover,and the long stator is only made by magnetic material.In this paper,a modular fault-tolerant PM vernier linear(LPMV)motor is proposed,which is based on the primary PM vernier motor.The finite element method(FEM)model of the motor is established to analyzing its electromagnetic properties.Moreover,the thermal simulation model of the motor is established and its thermal characteristics are analyzed.In addition,the performance of the proposed motor is verified by the experimental prototype,which laid the foundation for the further study of this kind of motors.The main contents of study are as follows:1.The structure characteristics of the magnetic field modulation motor are described,including the magnetic gear motor and the PM vernier motor.The principle of magnetic field modulation is analyzed in detail by analyzing the air-gap magnetically and verified by simulation of the stator-PM vernier motor.2.Aiming at the advantages and disadvantages of the existing primary LPMV motor,a modular primary structure is proposed,which realizes the magnetic decoupling between the adjacent phases of the motor,reduce the mutual inductance and improve the fault-tolerant capability of the motor.Meanwhile,the new PM array structure is adopted to reduce the magnetic flux leakage at the edge of the PM,increase the air-gap magnetic flux density and improve the utilization rate of the PM.Thus,the motor thrust performance is enhanced.3.The modular primary mover design and the new PM array structure of the modular Fault-tolerant LPMV motor are introduced and analyzed.Moreover,this paper introduces the basic structure of the motor and explains its working principle.Moreover,the electromagnetic properties of the motor are analyzed by FEM software,including the magnetic field distribution of the motor,the back electromotive force(back-EMF),the inductance,the detent force and the thrust characteristics,respectively.4.According to the proposed structure of the motor,the structure of the motor is optimized,including different slot/pole number combinations,optimization design of PM array structure parameters,optimization design of mover and stator structure parameters.Finally,the optimal structure of the motor will be determined.Moreover,the performance of the proposed motor will be compared with the existing one.5.Based on ANSYS Workbench,the finite element temperature simulation of the motor is carried out.According to the actual working characteristic of the motor,the temperature distribution of each part of the motor is simulated,and the temperature characteristic of the motor is analyzed.