Optimization Designed And Characteristic Analysis Of Double-Sided Permanent Magnet Linear Synchronous Machine With Equidirectional Toroidal Windings

Double-sided permanent magnet linear synchronous motors(DSPMLSMs)are widely used in transportation,express,industrial and aerospace fields due to some advantages of simple structure,convenient maintenance,low normal force,high power density and so on.In some applications of the limitations of space,DSPMLSMs are required to be able to output greater thrust density.In order to improve the thrust density of DSPMLSM,this paper presents a topological structure of DSPMLSM with equidirectional toroidal windings(EDTW),the operation principle is analyzed,the electromagnetic parameters are designed,the electromagnetic characteristics are analyzed,and the objective performances are optimized.The detailed research work of this paper is as follows:(1)A topological structure of DSPMLSM with EDTW(EDTW-DSPMLSM)is presented,the motor and EDTW structure are described,the synthetic electromotive force and winding coefficient of EDTW are obtained by vector synthesis method and formulas,based on the armature magnetic field of EDTW,the operation principle of EDTW-DSPMLSM is analyzed.(2)An EDTW-DSPMLSM is designed,according to the design requirements and basic parameters of the motor,the size equation of the motor is deduced,the primary parameters,secondary parameters and air-gap parameters are designed,the above design parameters are summarized and the electromagnetic parameters of the motor are obtained.(3)The electromagnetic characteristics of EDTW-DSPMLSM are analyzed,based on the similar electric load and magnetic load,compared with DSPMLSM with concentrated windings(CW-DSPMLSM)and DSPMLSM with traditional toroidal windings(TTW-DSPMLSM).The magnetic flux distribution,air gap flux density and back electromotive force(back-EMF)and detent force of the three motors are analyzed under no-load condition,the thrust,loss and efficiency of the three motors are analyzed under load condition.The simulation results show that EDTW-DSPMLSM has advantages in back-EMF and thrust density.Besides,combined with the existing conditions in the laboratory,9-slot 6-pole EDTWDSPMLSM is used for experimental tests to verify the feasibility of DSPMLSM using EDTW and the correctness of the finite element result.(4)The primary staggered tooth structure is adopted to optimize the detent force of the motor,the analytical formulas of the end force and cogging force of EDTW-DSPMLSM with staggered-tooth are deduced theoretically,and the analytical formulas are verified by the simulation results of the end force and cogging force.The results show that the detent force of EDTW-DSPMLSM can be effectively reduced by adopting the primary staggered tooth structure,but the back-EMF and thrust of EDTW-DSPMLSM are also reduced.In order to improve back-EMF and thrust of EDTW-DSPMLSM with staggered-tooth structure,the armature windings of EDTW-DSPMLSM are rearranged to improve the back EMF and thrust,based on the primary staggered-tooth structure.The characteristics of no-load back-EMF,thrust,loss and efficiency before and after EDTW-DSPMLSM optimization are analyzed by simulation.The simulation results show that the method combined with the primary staggered tooth structure and armature winding rearrangement is effective for the performance optimization of EDTWDSPMLSM.(5)The Taguchi method is used for multi-objective optimization of EDTWDSPMLSM to achieve the best performance of the motor,the finite element method is used to solve the orthogonal matrix,the influence proportion of optimization variables on the optimization goal is determined,the optimal combination of structural parameters for EDTW-DSPMLSM optimization goal is obtained,and the objective performances before and after motor optimization are compared and analyzed.The simulation results show that Taguchi method is effective for the performance optimization of EDTW-DSPMLSM.The above research work covers EDTW-DSPMLSM structure and working mechanism analysis,electromagnetic design,electromagnetic characteristics analysis,staggered tooth structure optimization design and multi-objective optimization design.The simulation results show that compared with CWDSPMLSM and TTW-DSPMLSM,EDTW-DSPMLSM has advantages in no-load back-EMF and thrust density,and some performances of the motor are improved by adopting the staggered tooth structure and Taguchi method,which is suitable for applications requiring high thrust density.This provides an important theoretical basis and simulation results for the following study of EDTWDSPMLSM.