Study On Key Technology Of Direct Drive Permanent Magnet Motor For Belt Conveyor Used In Mine

Belt conveyor is mainly in the production of mine,wharf,metallurgy,transport equipment,the performance of the drive unit directly affect the efficiency of coal production and the failure rate,asynchronous machine,coupler,reduction unit drive form of transmission link is more,the transmission efficiency is low,high failure rate,the problem of high maintenance costs,the permanent magnet direct-drive motor driven way there to take up the space is large,coupling of concentric docking is difficult problem,exterior rotor direct-drive motor driven belt conveyor to take up the space is little,the system stability,high efficiency.In this paper,the electromagnetic structure,temperature field,control mode and other key technologies of the external rotor permanent magnet motor used in belt conveyor are studied.The main work contents are as follows:(1)Conduct electromagnetic design for external rotor permanent magnet motor.By comparing the cogging torque and single side magnetic pulling force of three different cogging,the most suitable cogging was selected.The fractional slot winding is designed.The sinusoidal property of air gap flux density was improved by optimizing the shape of permanent magnet.The electromagnetic performance of the motor is simulated and analyzed.(2)Aiming at the problem of exterior rotor permanent magnet motor is not easy to heat dissipation,to accurately calculate the motor temperature rise,through the finite element method to calculate winding copper loss,and calculate the stator core yoke iron loss and tooth,a detailed analysis of permanent magnet eddy current loss,analyzed the different slit width,length of flavor,permanent magnet axial section number on the influence of the permanent magnet eddy current loss.The heat dissipation coefficients of each part were determined,and the electromagnetic-thermal multi-physical field simulation was carried out for the water-cooled motor.(3)In view of the belt conveyor load fluctuation,long time running at rated speed will accelerate the loss of mechanical parts and cause unnecessary power waste and mechanical parts wear problems.There exists the problem of unbalanced output power of each motor in multi-motor driving.An on-load speed regulation system and power balance system based on vector control based on i_d=0 are designed.The speed of the permanent magnet motor is automatically adjusted according to the load,so that the output power balance of multiple motors can be achieved,and the belt conveyor can run in energy saving.