Abstract: In order to solve the problems of low transmission efficiency,high failure rate and low reliability caused by the existence of reducer in the traditional asynchronous drive system for scraper conveyor,based on the permanent magnet synchronous motor,a permanent magnet direct drive system for the scraper conveyor with an annual capacity of 15 million tons is de-veloped,and the required power,speed and variable frequency controller capacity of the perma- nent magnet syn-chronous motor are calculated. According to the electromechanical coupling relationship between the permanent magnet direct drive system and the scraper conveyor,the electromechanical coupling model of the scraper conveyor is established in the MATLAB / Simulink. And the law of dynamic characteristic change of the output speed, torque,and three-phase current of PMSM and chain speed,acceleration and displacement of scraper conveyor are sim- ulated and analyzed under typical working conditions such as no-load startup,full load,and polygon effect. The simula- tion results show that the permanent magnet direct drive system can respond quickly and accurately when the scraper conveyor starts and the load changes. The output speed and torque of the motor fluctuate greatly in response to the sud- den load change without reducer. The dynamic response of the permanent magnet direct drive system has a positive correlation with the sudden change. Therefore,the optimization of the control algorithm of the drive system should be considered to improve its performance. The polygonal effect affects the stability of the speed control system,and the chain at the mesh of the head sprocket is more susceptible to the polygonal effect. Finally,the simulation test bench of small power PMSM direct drive is established,and the mechanical load characteristic curve obtained from the simula- tion is treated equivalently and then input through the dynamometer,and the simulation drive test of the PMSM drive system for scraper conveyor is carried out. The results show that the change trend of the characteristic curves of the PMSM obtained by the experiment is basically consistent with the characteristic curves of the PMSM obtained by the simulation,thus the correctness of the electromechanical coupling model of the PMSM direct drive system for scraper conveyor is verified from the side.