Design And Study On Surface-Mounted Outer Rotor Transverse Flux Permanent-Magnet Motor

Compared with the traditional AC motor,transverse flux permanent-magnet motor(TFPM)has the advantages of high output torque density,design flexibility as well as modular structure,also it is easy to fabricate the structure forms of multi-phase and multi-pole.Because of its great prospect in low speed and high torque electric-driven applications,TFPM has become an important branch of new special motor structure.However,subjected to the complex magnetic structure,TFPM has the defects of aspect in manufacturing costs,structural magnetic leakage and torque ripple,which hinders its further development and practical application.This thesis carries out the work about topology design and characteristic study of a surface-mounted outer rotor transverse flux permanent-magnet motor(SMOR-TFPM)with simple structure and good performance.First,the topology structure and operating principle of the motor are introduced,its equivalent magnetic circuit is established by focusing on the magnetic circuit analysis,and the mathematical model is given so that the relevant motor characteristics can be revealed in theory.The dimensions and their mutual relations of the motor are illustrated then,the design process of the structure parameters is given on the basis of improving the torque density of the motor.The design ideas and principles of the stator and rotor are also discussed with combining the structure and performance features of the motor.According to the deficiency of the SMOR-TFPM electrical performance,this thesis presents the improved design of the stator so that the motor performance can be improved by transforming the part of the leakage flux into the main flux.The finite element model of the motor is established.The effect factors of the key performance including the magnetic leakage and torque ripple are researched based on the numerical computation of three-dimensional electromagnetic field.The thesis also optimally analyzes the influence of the relevant parameters such as pole width and teeth-width coefficient on the no-load magnetic leakage coefficient.Besides,the thesis discusses about changes in pole-arc coefficient,rotor-skewing and multi-phase composite have an influence on the cogging torque.Optimization design rules are summarized to provide the theoretical guidance to reduce the magnetic leakage and cripple the torque ripple of the SMOR-TFPM.Finally,dimensions design of a three-phase SMOR-TFPM is completed according to the acquired design methods and optimization results.The motor characteristics are analyzed by the electromagnetic simulation software.The three-dimensional finite element method is used to analyze the motor magnetic field distribution,no-load back EMF and winding inductance as well as power factor.The motor torque characteristics are analyzed from multiple aspects which include the analysis and calculation of the single-phase static torque and three-phase synthetic electromagnetic torque etc.In addition,the efficiency is calculated.The results prove that the structure and dimensions design of the motor is reasonable and the characteristics are stable,which has a certain feasibility.