Research On Optimization Design Of Permanent Magnet Rotor Pole Of Upgrade Remanufacturing Motor

As the largest electrical equipment terminal in the industrial system,the motor is used in a wide range of fields such as national defense,aerospace,transportation,industrial and agricultural production.According to statistics,the annual electricity consumption of electric motors in China is about 6 trillion kilowatt hours,accounting for 50% of the total electricity consumption in society.However,the efficiency of China’s electric motor system lags behind the average level of developed countries,with over 60% of the motors being old and inefficient asynchronous motors.Their motor efficiency is more than 5% lower than that of similar foreign products,which cannot meet the current energy efficiency level required by society.How to replace and eliminate the old and inefficient motors with efficient motors has become a difficult problem that China’s industrial transformation and upgrading must overcome.Motor upgrading and remanufacturing is an ideal way to solve this problem.This article is about keeping the stator winding,end cover,and junction box of an old and inefficient motor stationary,removing the original squirrel cage structure,and optimizing the design of permanent magnetization for the rotor.By changing the three parameters of pole cutting angle,pole arc coefficient,and thickness,oblique poles are used to reduce costs while improving the efficiency of the motor and reducing vibration noise.The main research content is as follows:(1)Design a plan for upgrading and remanufacturing the motor.Without changing the stator and winding structure of the asynchronous motor,remove the squirrel cage structure,use neodymium iron boron material as the magnetic pole,and select a surface mounted rotor in structure.Upgrade and remanufacture the rotor into a permanent magnet rotor.(2)Calculate the fundamental and harmonic values of the air gap magnetic density corresponding to different pole arc coefficients,pole cutting angles,and thicknesses through finite element simulation.Then,optimize the design by reducing the harmonic value to make the air gap magnetic density waveform tend towards a sine wave.Firstly,the influence of a single magnetic pole parameter on the fundamental and harmonic values of the air gap magnetic density is studied;Then study the influence of combined magnetic pole parameters on the fundamental and harmonic values;Finally,the optimal magnetic pole parameters are determined as follows: when the pole cutting angle is set at a position of 45 mm along the X direction,the Y-axis cutting angle is 55 degrees,the pole thickness is set at 11 mm,and the pole arc coefficient is set at 0.88.The minimum harmonic content of the air gap magnetic density waveform is 16.25%.(3)Design the rotor magnetic pole using the optimal parameter values obtained through simulation,and use the oblique pole process to upgrade the 55 kw asynchronous motor into a 55 kw quadrupole permanent magnet synchronous motor.Before the upgrade,the motor efficiency was 86% and the vibration noise was 93.1d B;After the upgrade,the motor efficiency is95%,and the vibration noise is 80.9d B,achieving a 9% improvement in motor efficiency and a 12.2d B reduction in vibration noise.Based on the research results of this article,the transformation from inefficient motors to high-efficiency motors has been achieved,solving the problem of high energy consumption and inefficient motors and their recycling,which is conducive to achieving the dual carbon strategy goal and providing guidance and important significance for the development of circular economy in the motor remanufacturing industry.