Analysis And Optimization Design Of Outer Rotor Permanent Magnet Synchronous Motors For Traction Machines

In daily life, as vertical lifting transportation tools, elevators occupy small area, and it can also send the passengers and goods to different floors in a safe, reasonable and effective way by electric or other means of control. The elevator has become an important part of people’s work and life, for it has more advantages. A traction machine, as the main component of the elevator,usually consists of a motor, a reducer, a brake, a base component and so on. One of the main parts of traction machine is motor. Therefore, the motor is one of the main components of elevator.The traditional traction machine mostly uses three-phase asynchronous motor. This motor is of low efficiency.Moreover, its noise is large as well as its vibration is terrible. Its installation and maintenance are difficult. However, the permanent magnet synchronous motor has the advantages of small volume, energy efficient, output torque smooth, large starting torque etc. It is a special motor of new type of high efficiency and has been a good evaluation in the various motor production enterprises, universities and research units. However, the permanent magnet synchronous motor exists the problem of cogging torque and electromagnetic noise.This subject comes from Guangzhou Guangri Elevator Industry Co. Ltd., which is about the design and optimization of an outer rotor permanent magnet synchronous motor for traction machine.Its goal is to achieve the advantages of high efficiency, small vibration, low noise, low cogging torque and so on. Firstly, the paper introduces the basic structures, working principles and mathematical models of permanent magnet synchronous motor. Then it introduces related knowledge of ANSYS software and how to establish two-dimensional model through ANSYS finite element software of Maxwell module. The slot pole combination of permanent magnet synchronous motor is selected to 36 slot 30 pole, 36 slot 32 pole,36 slot 34 pole through theoretical analysis. The three slot pole combinations carry out radial force wave analysis, optimizing fractional slot permanent magnet synchronous motor of electromagnetic noise. And through the comparative analysis, the best slot pole combination is 36 slot 30 poles, which can effectively reduce the harmonic wave content of air gap magnetic density. In addition, since permanent magnet synchronous motor exists problem of cogging torque, according to the mechanism that permanent magnet synchronous motor produces cogging torque,the cogging torque is analyzed, through optimizing the pole arc coefficient and using unequal thickness permanent magnet, the cogging torque of the permanent magnet synchronous motor can be effectively reduced. the finite element model is established based on Maxwell2D, both magnet of the pole arc coefficients and the eccentricity are set as variable, then they are sent to scanning analysis. The simulation results show that, within a reasonable range, there is an optimal pole arc coefficient and eccentricity to reduce the cogging torque of the motor significantly. Finally, a prototype is developed according to the optimization of the size parameters, so that among various performance parameters of prototype, vibration of prototype and noise of prototype are tested. By comparing the performance of prototype with the Maxwell2D simulation value results indicate that the error of the main performance index are within 5%, which can meet the requirements of the design and optimal, and also verify the correctness of the Maxwell2D finite element simulation. This paper has a very high reference value in engineering practice and theory.