Optimization Of Magnetic Resistance Of Permanent Magnet Linear Synchronous Motor For Vertical Lifting

The development of social economy promotes the concentration of population in cities.In order to improve the spatial density,high-rise buildings have sprung up,and elevators have become indispensable building equipment.Permanent magnet linear synchronous motor(PMLSM)has the advantages of simple structure and high thrust density of permanent magnet motor and linear motor.It can be used as the preferred driving source of vertical lifting system.However,the permanent magnet linear motor has magnetic resistance,including the cogging force caused by the primary iron core slotting and the end force caused by the longitudinal end breaking,which makes the permanent magnet linear motor produce thrust fluctuation and seriously affect the control performance of the system.Therefore,the research on magnetic resistance suppression has important theoretical and engineering practical significance.Aiming at the general deficiency of magnetic resistance in the existing PMLSM,this paper puts forward optimization measures.The specific work is as follows:This paper introduces the development status of PMLSM and vertical lifting system,analyzes the relevant research status of cogging force of permanent magnet motor and end force of linear motor at home and abroad,and gives the research significance of the subject.The structure and working principle of PMLSM are described,and the generation mechanism of magnetic resistance is studied.The mathematical models of cogging force and end force of PMLSM are established by energy method and Fourier method,and the influencing factors of cogging force and end force are analyzed.A novel three-stage magnetic slot wedge structure is proposed to suppress the cogging force of PMLSM.The suppression principle of cogging force of each magnetic block of three-stage magnetic slot wedge is analyzed by Fourier and finite element method.Taking 6s8p-PMLSM as the research object,the finite element model is established,the structural parameters of the new slot wedge are reasonably optimized,and the electromagnetic characteristics such as cogging force,magnetic field,back EMF,thrust and fluctuation of the initial motor,single magnetic slot wedge motor and three-stage magnetic slot wedge motor are compared and analyzed.The research shows that the new slot wedge can significantly reduce the cogging force and thrust fluctuation of the motor,and ensure that the average thrust does not decrease,which provides a new technical way for the cogging force suppression of permanent magnet motor.Finally,a three-stage magnetic slot wedge PMLSM prototype is developed,and its magnetic resistance is tested to verify the rationality of the theoretical analysis and finite element simulation of the new slot wedge.Research on cogging force suppression based on multi segment combined PMLSM.In order to solve the problem of sharp increase of thrust fluctuation caused by the superposition of cogging force of combined motor in the vertical lifting system with large thrust and long stroke,a new combined PMLSM structure is proposed to study the influence of tooth boot on the cogging force and thrust performance of motor.By changing the length of tooth boot between different unit motors,the total cogging force is superimposed and offset to reduce the thrust fluctuation.Taking 3s4 p PMLSM as the element,the 6s8 p PMLSM finite element analysis model is established,the optimal parameters are optimized,and the electromagnetic characteristics of different combined motors are compared and analyzed.Finally,the specific design principles of unequal tooth boot combined PMLSM with different number of units are given,and the multi-objective optimization is carried out with high thrust and low fluctuation as the optimization objective and the tooth boot parameters of each unit as the optimization variables.Research on end force suppression of PMLSM Based on additional auxiliary teeth of primary core.Firstly,the principle of restraining the end force of the auxiliary tooth is analyzed,and the end force of the auxiliary tooth is analyzed according to the Fourier decomposition,the optimal position of the opposite phase of the end force of the auxiliary tooth and PMLSM is deduced,the PMLSM finite element model based on the auxiliary tooth is established,the width and height of the auxiliary tooth are optimized in turn,and the structural parameters of the auxiliary tooth with the minimum magnetic resistance are obtained.There are 58 figures,7 tables and 77 references.