Research On Cogging Torque Of Three Phase Permanent Magnet Synchronous Motor

The permanent magnet synchronous motor has been more and more widely used in fields such as high precision control,transportation,medical treatment,spaceflight and industrial 4.0 eras due to its high efficiency,simple structure,wide speed range,high torque density,fast response ability and high energy saving.Although permanent magnet synchronous motor has many advantages,but there is an inherent torque called cogging torque due to the material of the permanent magnet synchronous motor structures.The reason is the adsorption of permanent magnet and the stator,this force makes the rotor always stay in one place.Cogging torque exist although no power and it makes the output torque of permanent magnet synchronous motor fluctuations,thus affecting the motor control accuracy,resulting in larger noise and vibration in the process of the motor running.For permanent magnet synchronous motors that require long hours of operation in high precision environments,cogging torque must be attenuated and eliminated.At present,most of the research about cogging torque of permanent magnet synchronous motor focuses on the cogging torque itself in the world.By observing the experiment of weakening the cogging torque,we found that most of the measures to reduce the cogging torque of the permanent magnet synchronous motor often bring about the synchronous decrease of the electromagnetic torque of the motor.This is due to the internal distribution of permanent magnet synchronous motor magnetic field is accompanied by the change of the structure of permanent magnet synchronous motor body structure parameters.For example,skew can reduces cogging torque effectively,but it causes an increase in the end-leakage flux of the permanent-magnet synchronous motor.This paper elaborates and verifies the effect of the current feasible method on electromagnetic torque caused reduce cogging torque of permanent magnet synchronous motor.The specific work and innovation of this article are as follows:1.Used ANSOFT Maxwell designed one of the surface-mount and built-in permanent magnet synchronous motors separately and calculated the cogging torque and the electromagnetic torque.2.According to the finite element analysis principle and the formula of cogging torque and electromagnetic torque of permanent magnet synchronous motor,starting from the factors that affect the cogging torque,make the structure parameters of permanent magnet synchronous motor into a separate change,analysis the cogging torque and electromagnetic torque of the prototype model quantitative and summarized the parameter optimization measures for surface-mounted and built-in permanent magnet synchronous motors.3.Introduce the multi-dimensional optimization method,and use the combination of orthogonal design to optimize the design of each combination of the design measures.The weight ratio of each measure to the optimization objective is obtained.