Research On The Design And Optimization Method Of Low Power Permanent Magnet Synchronous Linear Motor

With the country vigorously promoting industrial modernization,the research and development of all kinds of precision manufacturing equipment have been put on the agenda,and an important part of improving the accuracy of manufacturing equipment is to remove the mechanical transmission system,using electric machines directly drive them for high-precision positioning.Compared with the traditional rotary motor with mechanical transmission system,permanent magnet synchronous linear motor(PMSLM)can directly move in a straight line without using mechanical transmission system,so it can greatly improve the positioning accuracy of the equipment.It has been widely used in some high-end machining centers abroad.At the same time,there are cross-sections at both ends of PMSLM movers,which lead to a large detent force,which has a negative impact on improving its positioning accuracy.Aiming at the problem that the detent force of low-power PMSLM which is widely used at present is generally too large,this thesis first uses the traditional PMSM electromagnetic design scheme,after some modifications,redesigns a PMSLM that basically meets the given technical indicators,and verifies the technical indicators of the preliminary designed PMSLM by using FEM simulation.Generally,the preliminary design of PMSLM model has the problem of too large positioning force.Therefore,this thesis proposes the calculation method of air gap magnetic field based on the separation variable method after the modification of PMSLM and the calculation method of air gap magnetic field based on the conformal mapping method after the modification of PMSLM,analyzes the air gap magnetic field of the preliminary design of PMSLM,and obtains a series of geometric parameters that affect the detent force of PMSLM.Then,the end tooth width,the end slot width,the end tooth height and the eccentric radius of the tooth surface are selected as the optimization variables.The parametric scanning method is used to scan these variables in order to obtain their effects on the detent force.Since the detent force of PMSLM is a multi-variable and non-linear function,it takes a long time and is inefficient to optimize by using the traditional global parametric scanning method,so it is necessary to find an efficient global optimization algorithm to optimize the detent force of PMSLM,and the genetic algorithm,which is simulating the evolution process of biology,just fits the demand of this.Therefore,After the range of these optimization variables are determined,genetic algorithm is chose to optimize the excessive detent force of preliminary design PMSLM.Finally,this thesis compares the optimization results of genetic algorithm with the preliminary design model.The results show that after the optimization of genetic algorithm,the detent force of the designed PMSLM is greatly weakened,and the thrust fluctuation under the rated load is also reduced,and the asymmetry of the three-phase no-load back EMF is also reduced.