Study On Thrust Force Of Permanent Magnet Linear Synchronous Motor And Its Direct Thrust Force Control System

Linear machine direct driving system combined the linear motor and control technology has superiority over rotating motor in industrial areas. The Linear machine direct driving system contains potential application along with the further developing of power electronic technology and various novel control strategies as well as high performance magnetic materials.This dissertation has project background of the National Natural Science Foundation which is titled "Precision direct driving technology and control strategy research on slewing servo of numerical controlled machine tool (No.50375102)". Focus on key research and status in quo about direct driving technology, linear machine and its control method have been studied.Improving thrust force and reducing size are the main problems for linear machine research. The dissertation have synthetically investigated by means of three methods, analytical analysis, numerical analysis and test, that the finite element method magnetic field analysis, electromagnetic force calculation, variational parameters affect on thrust force and thrust force experiment research.Relationship between the thrust force and structure parameters such as mover parameters, airgap and permanent magnet sizes has been derived An analytical expression of thrust coefficient per volume has been also derived from basic electromagnetic laws. Using these analytical methods, it realizes general anylysis such as thrust force changing with the linear motor structure parameters.The dissertation develops the rotating machine direct torque control into the linear machine control. And the control system of permanent magnet linear synchronous motor based on DSP is equipped also. Direct thrust force control method for the linear motor in theory and experiment has been further studied.A robust control method of sliding model variable structure direct thrust force has been presented in the control system of the linear motor direct driving system so as to solve many factors effect on control performance and realize the goal of weakening force ripple and good respond performance.Fuzzy sliding model direct thrust force control in the paper combines their advantages together of the fuzzy control and the sliding model control, which is useful for solving chattering problem of the sliding mode control. The system chattering has been effectively restrained.