Research On Direct Drive System Of Permanent Magnet Motor For Belt Conveyor

As an important conveying equipment,the structure of the driving part of belt conveyor has changed with the development of permanent magnet motor,from the traditional asynchronous motor + reducer + coupling + mechanical roller to the outer rotor permanent magnet direct drive roller.Compared with the two,the outer rotor permanent magnet direct drive roller shortens the transmission chain,abandons the reducer,and reduces the oil leakage Problems,improve the efficiency of the system.When the driving structure of belt conveyor changes,the conveying distance is also gradually lengthened.On the one hand,it is to improve the single power of permanent magnet direct drive motor,on the other hand,it is selected to drive the belt by multiple permanent magnet direct drive motors.The main research contents are as followsAiming at the multi-point driving problem of long-distance belt conveyor,combined with the running resistance of belt conveyor,the power distribution of motor in multi-point driving is given;when determining the middle position of multi-point driving,according to the principle of equal circumferential force or equal envelop angle,combined with the actual working conditions,the layout mode of equal distance or equal tension and the specific calculation method are given,which can provide reference for the subsequent multi-point driving The driving model design provides theoretical support.Combined with the design requirements of belt conveyor drive motor,a surface mounted permanent magnet direct drive roller is designed.The generation of torque ripple is analyzed theoretically.Cogging torque and ripple torque are the main factors.The pole slot matching has an important impact on torque ripple.Through the comparison of three different pole slot matching,the one with the smallest torque ripple is selected for prototype production,and fractional slot is designed Through the comparison of flat bottom permanent magnet and concentric circle permanent magnet,flat bottom permanent magnet air gap flux density waveform has better sinusoidal degree and less harmonic content;for the heat dissipation of external rotor permanent magnet motor is difficult,the prototype chooses water cooling,designs the cooling channel of permanent magnet direct drive roller,builds the experimental platform and carries on the prototype No load,load and temperature rise experiments,the design and prototype experiments are compared and verified.Aiming at the problem of optimizing the wall thickness and reducing the volume of the motor,the model of the wall is simplified and the stress analysis is carried out.The permanent magnet direct drive roller wall is modeled,and the force on the wall is applied as a load.The deformation variables of the wall under five different thicknesses are compared and analyzed.On the premise of meeting the mechanical strength,the output torque is unchanged,and the volume and material consumption of the motor are compared with the original There is a decrease.Aiming at the problem of long-distance transportation and uneven load in the process of belt conveyor,combined with the actual working conditions,using the vector control model of id = 0,a load adaptive three drive control system is designed,which can select the number of input drive motors according to the load.When the motor is under light load,the number of input motors is reduced,the load of a single motor is increased,and the system efficiency is improved When two or more motors are put into the multi drive system,on the basis of adjusting the number of motors according to the load,the power balance between the multi drive systems can be realized to ensure the safe and energy-saving operation of the belt conveyor.Finally,the control module is built and the simulation model is established.The output current and torque waveforms of the multi drive system are obtained by simulation,and the correctness of the control system is verified.