Design And Optimization Of Double Stator Low Speed Large Torque Permanent Magnet Synchronous Motor

Due to the high efficiency,high power factor,and flexible topology,the permanent magnet direct drive system consisting of low speed large torque permanent magnet synchronous motor(PMSM)is gradually replacing the traditional low speed transmission system composed of asynchronous motor and mechanical deceleration device,and PMSMs have gradually become the mainstream motors applied in the industry of ship propulsion,lifting machinery,ore mining and transportation.However,the traditional low speed large torque PMSM has a flat shape due to its large diameter-to-length ratio,and there is still a large space inside the rotor of the motor that is not fully utilized.This paper uses a double stator topology to take advantage of that space to increase the power and torque of the motor with limited external dimensions.The double stator topology increases the difficulty of motor design,and there is currently no definite design method for the double stator motors.In this paper,a double stator low speed large torque PMSM for mining conveyor belt is designed.The main research contents are as follows:First of all,by consulting the domestic and foreign literature related to the subject,the background significance of the research,the current development status of the subject,and the problems encountered in the course of the project are pointed out.The structure of double stator permanent magnet motor is introduced.The form and selection of magnetic circuit structure of double stator motor are discussed.Secondly,based on general methods of motor design,combined with the characteristics of the double stator permanent magnet motor,the electromagnetic design of the double stator low speed large torque PMSM is carried out.The main work includes: the determination of rated parameters of the motor,the selection of pole slot fit,the design and matching of stator winding of the motor,the determination of internal and external permanent magnet dimensions,the determination of main structural dimensions of the motor,etc.In addition,based on the magnetic circuit structure adopted by the motor,the lengths of inner and outer air gap,the widths of inner and outer permanent magnet,and the thicknesses of inner and outer permanent magnet are determined as control variables.Then,the Taguchi method is used to study the effects of these six variables on the no-load performance of the motor(back electromotive force and cogging torque).By the processing and analysis of the data,the optimal combination of parameters is available.Finally,the finite element analysis is used to verify the rationality of the designed motor.Finite element simulation model of the designed motor is established in ANSYS,and the simulation of the no-load and load characteristics of the motor is carried out.The simulation mainly includes: the magnetic field distribution of the motor under different load condition,the distribution of magnetic field in the internal and the external air gap under different load condition,the cogging torque of the motor,and the no-load back EMF of the motor,etc.