Design Of Permanent Magnet Synchronous Linear Motor For Machine Tools And Research On The Control System

With the continuous development of motor and motor control technology,the motor system with direct drive load has begun to replace the traditional drive system with complicated mechanical structure.As a typical representative of direct drive system,Permanent Magnet Synchronous Linear Motor(PMSLM)has become the preferred solution for machine tool equipment upgrading.This paper focuses on the following aspects of PMSLM design and its control system:According to the design method of rotating permanent magnet motor,the main size formula suitable for permanent magnet linear motor was deduced,and the electromagnetic design was carried out for a PMSLM of 800 N.In this paper,the characteristics of the fractional slot of linear motor are analyzed,and the effects of three different slot types on the magnetic field distribution,back EMF and no-load loss of the motor were compared.An analytical calculation method of PMSLM inductance was proposed based on equivalent magnetic network and mesh magnetic flux method.The finite element simulation model was established to simulate and analyze the design scheme of the motor.The weakening of PMSLM detent force was studied.Firstly,the detent force was decomposed into end force and cogging force.The main even harmonics of the end force were analyzed in this paper,the method of optimizing the core length and the non-uniform air gap of the end teeth were used to weaken the two and four harmonic components of the end force respectively,the advantages and disadvantages of weakening the end force by oblique pole were discussed.The effects of single-layer and double-layer winding on the cogging force and inductance parameters were compared.After optimization,the motor positioning force was weakened greatly.Finally,the PMSLM mathematical model was derived and the PMSLM simulation model in Simulink environment was established.Through simulation analysis,the field oriented control method suitable for PMSLM was studied,and the q-axis current feedforward compensation method was used to reduce the thrust fluctuation in high-precision control,and the correctness of the control method was verified.