Research On Torque Ripple Suppression Method And Inductance Characteristics Of Permanent Magnet Synchronous Servo Motor

Servo system is the core component of industrial manufacturing,but domestic products still have a big gap compared with foreign countries.In order to promote the development of China’s manufacturing industry,in-depth research is necessary.As the transmission mechanism of the servo system,the permanent magnet synchronous motor has been widely used due to its high power density.However,the permanent magnet motor has two major defects,namely the problem of the torque ripple and the inductance change.The former reduces the accuracy of the system and the latter Limit the response speed of the system..Therefore,studying the method of restraining torque fluctuation and studying the law of inductance change has important academic value and engineering significance.This thesis first systematically expounds the theory of permanent magnet motors,points out the advantages and disadvantages of various structures,and derives the mathematical model of permanent magnet motors.In order to clarify the optimal design direction of servo motors,this thesis derives cogging torque based on the energy method.the harmonic order of torque fluctuation is derived through electromagnetic power,and derives the expression of overload capacity and maximum speed.Secondly,this thesis presents the analytical design method of the servo motor,and designs a surface-mount permanent magnet motor based on this method.The finite element simulation shows that the scheme meets the design index requirements,but the performance can be further improved.On the basis of this model,the influence of structural parameters such as eccentricity,pole arc coefficient,oblique pole method,slot width,tooth shoe height and auxiliary slot on torque fluctuation is studied.Based on Taguchi’s orthogonal method,the multi-objective optimization of the initial model with multiple design variables is carried out.Then two interior permanent magnet motors with different rotor structures were designed and use particle swarm algorithm to optimize the motor globally.The internal reasons for the change of inductance and the simulation method of the inductance are explained.The change rule of q-axis inductance when the design model parameters are changed is calculated by using the frozen permeance method.The calculation results proved that the non-uniform air gap scheme can simultaneously optimize the torque ripple problem and the inductance change problem.Finally,according to the designed surface mount motor and interior permanent magnet motors scheme,prototypes were made for testing,and the rationality of the design was verified.A method to quickly reflect the magnitude of torque fluctuations with the help of upper computer software is proposed.This method proves that the torque ripple suppression scheme proposed in this thesis is effective;the change trend of inductance is qualitatively analyzed through the relationship between current loop gain and current response.Summarizing the above-mentioned work,this article uses Taguchi orthogonal method and particle swarm algorithm to suppress torque fluctuations.Both optimization methods have achieved good results,which can provide reference for the related design work of motors;The inductance simulation method is used to calculate the inductance characteristics after various structural parameters are changed;two prototypes of surface mount type and interior permanent magnet type are produced,and the measured data verify the rationality of the design.