Research On Direct-drive Solid Magnetic Pole Permanent Magnet Motor For Mining Belt Conveyor

Compared with the traditional asynchronous motor drive system,the direct-drive permanent magnet motor drive system of the mining belt machine shortens the transmission link,reduces the energy loss during the transmission process,and improves the efficiency and stability of the drive system.The permanent magnet motor rotor magnetic pole adopts laminated structure,but this kind of structure has the disadvantages of low mechanical strength and cumbersome process.Compared with the laminated structure,the solid magnetic pole for a permanent magnet motor has the advantages of simple structure,high mechanical reliability,low vibration and electromagnetic noise.However,the solid structure will cause large eddy current loss inside the magnetic pole,causing the rotor temperature rise too high,which may cause irreversible demagnetization of the permanent magnet,which will affect the working performance and service life of the permanent magnet motor.Aiming at the problems of solid magnetic pole permanent magnet motor,the main research contents of this thesis are as follows:The selection basis of the number of slots per phase per pole of the direct-drive permanent magnet motor for mining belt conveyor is given.The cogging torque of the motor is compared and analyzed with the combination of the 72-slot 60-pole and the 72-slot 30-pole.The relationship between the change of the air gap length and the amount of permanent magnets is analyzed,and the amount of permanent magnets increases nonlinearly with the increase of the air gap length,and the growth rate gradually increases.In order to solve the problem of high working temperature and difficult heat dissipation of the mining belt conveyor,the thermal load of the motor is optimized.According to the requirements of the flameproof of the motor,the flame-proof gap of the joint surface of the motor and the joint surface of the shaft is designed.Aiming at the problem of large eddy current loss of solid magnetic pole,the influence of stator slot opening and rotor uneven air gap on the eddy current loss of solid magnetic pole is analyzed.It is concluded that the eddy current loss of the solid magnetic pole increases with the quadratic function of the opening of the stator slot,and decreases with the increase of the multiple air gap of the rotor.The axial thermal conductivity of the solid and laminated magnetic poles is studied differently,and the different thermal conductivity coefficients are given and applied to the temperature field analysis.The temperature distributions of solid,laminated magnetic pole motor casings,stator windings and rotor poles were obtained and compared.On the basis of design and analysis,two prototypes of solid and laminated magnetic poles were fabricated,and the experimental platform was built and the prototype was tested.The experimental test content mainly includes: temperature rise test,no-load back EMF test,vibration and noise test.Both calculation and experiment show the correctness of the research results,which provides a reference for the design and further application of the mining magnetic belt permanent magnet motor.