Reaserch Of Direct-Drive External Rotor PMSM Of Conveyor Belt

The application of induction motor combined with reducer is the primary driving device of mechanized equipment. However, with development of science and technology, it is widely concerned by direct-drive mode which is high power and high efficiency energy saving. Therefore, it is very significative to apply external rotor PMSM to replace the application of induction motor combined with reducer to drive the mechanized equipment. In this thesis, mechanized equipment is driven directly by external rotor PMSM to achieve the goal, which can be high efficiency energy saving. The rotor is located at outside, and the stator is located at inside. The main work includes three parts:The main characteristic of external rotor PMSM is summarized by analyzing the structure of the external rotor PMSM. Design procedure is adopted to design a 15kW, 20 poles prototype combining with the principle of conventional PMSM. The design process is presented detailed.Make use of the Ansoft finite element analysis software to set up 2D model of the prototype and simulate electromagnetic field of the prototype to get simulation results of the prototype such as: no-load back- electromotive force; magnetism flux density; magnetic field distribution. The forming reason of cogging torque in external rotor PMSM is analyzed. Fraction slot is adopted, combining with the structure characteristics of external rotor PMSM, to depress the influence of cogging torque. Then,by analysis and comparison the difference of eddy-current loss between the integral PM and the sectional PM. The results show that the eddy-current loss of sectional PM and the temperature rising caused by the eddy-current loss on the surface of magnet steel is lower than integral PM, and then it can reduce the possibility of demagnetization. These prove the electromagnetic scheme of the external rotor PMSM is feasible in theory. In this paper, hollow shaft is selected to be the shaft based on the characteristic of external rotor PMSM. Make use of the ABAQUS finite element analysis software to set up 3D model of the prototype. Mechanical analysis and simulation have been made on the shaft and rotor shell of the prototype under the condition of maximum load, and their reasonability are also proved.