Study On The Design And Control Technology Of The Permanent Magnetic Direct-Drive Roller Used In Belt Conveyor

Belt conveyor is commonly used to transport machinery in mines,it usually works with the help of tynchronous motor,coupler and gearing, which exists the problem of long driving chain, low efficiency and high maintenance costs.This paper put forward a kind of external rotor direct-drive permanent magnet synchronous motor(ERDD-PMSM).We mainly analyzed the problems of permanent magnet easily damageable of the radial structure permanent magnet synchronous motor(RSPMSM),concentric arc shape permanent magnet air-gap flux density waveform with poor sine degrees, harmonic content high;and heat dissipation problem of the inner stator structure; and the ring current between parallel winding branches of the low speed high torque motor.The main research results are reflected in the followings:Fristly,for RSPMSM has the problems that permanent magnet easily damaged,waveform difficult optimzated.A tangential structure permanent magnet synchronous motor(TSPMSM) was proposed. The method to optimize the air gap magnetic filed waveform was presented by comparing the air gap magnetic field waveform of RSPMSM and TSPMSM in different non-uniform air gap,and the gas flux density waveform distortion rate was calculated.Secondly,for the ring current between parallel winding branches of the low speed high torque motor,the mechanism of ring current and reduction method were studied.The ring current expression was analyzed. The simulation model of ring current in three different connections was established,and the connections to reduce ring current were analyzed.Thirdly,the electromagnetic filed,temperature field,and production cost were analyzed,The prototype of a belt permanent magnet direct-drive roller was produced according to the designed scheme of the motor.Finally, for the big load volatility of the belt,low working efficiency of the system,the variable frequency speed control system was designed.By using the inverter and programming card to realize the function that the motor can change speed automaticlly according to the mount of material,so as to realized the purpose of saving energy.