Design And Optimization Of A New Type Of Tubular Flux Swithcing Permanent Magnet Linear Machine

Linear machine plays an important role in industry and life because of its simplicity,accuracy and reliability.Compared with the traditional linear motion realized by rotary machine,linear machine does not need the middle "ball screw" transmission device and directly realizes the linear motion,and has the advantages of simple structure,fast response and high system efficiency.In linear machine,tubular flux switching permanent magnet linear machine can avoid the transverse side-end effect caused by horizontal disconnection of flat-plate linear machine,and overcome the unilateral tension,so that the machine can run more smoothly.At the same time,flux switching machine makes the machine structure more simple.However,the traditional tubular flux switching permanent magnet linear machine has a large amount of eddy current loss due to the vertical passage of flux through the stator yoke through the silicon steel sheet.Compared with the silicon steel used in traditional machines,the soft magnetic composite(SMC)has three-dimensional magnetic conductivity,small eddy current loss and is widely used in the manufacturing of machines.However,the material has low permeability,so the motor thrust is reduced and the hysteresis loss is large at low frequency.In this paper,according to the shortcomings of these two machines,the research work is carried out,mainly including the following contents: a new type of tubular flux switching permanent magnet linear machine is proposed to reduce the heat and loss of the traditional machine and improve the thrust of SMC machine.At the same time,the special end effect of linear machine is analyzed and studied,and a method is proposed to weaken the end effect and thus reduce the cogging force and thrust ripple.Firstly,the structure and operation principle of linear machine are introduced in detail,different types of linear machines are classified,advantages and disadvantages of linear machine are analyzed,and the principle of flux switching is briefly described.Secondly,a hybrid core solution is proposed to solve the problem of the traditional tubular flux switching permanent magnet linear machine,that is,a large amount of eddy current loss is generated when the flux passes through the silicon steel sheet vertically at the yoke of the stator.By using soft magnetic composite,the lamination direction of silicon steel sheet in the traditional motor is changed,and the core loss and thrust ripple are obviously reduced under the condition of little change of thrust.To solve the problems of low permeability and low frequency hysteresis loss of the motor made of SMC,silicon steel sheet is added to improve the motor performance.At the same time,the main parameters of the motor are optimized,including tooth groove matching,permanent magnet thickness,tooth groove width,airgap and other parameters.Finally,according to the unique end effect of linear machine,a solution of unequal width stator is proposed,which can weaken the end effect of the motor and reduce the cogging force and thrust ripple of the machine.Through the research and analysis in this paper,some ideas are provided for the future design of tubular flux switching permanent magnet linear machine.