Winding Design And Magnetic Steel Optimization Of Coreless Axial Flux Permanent Magnet Synchronous Motor With PCB Stator

The disc-type coreless permanent magnet synchronous machine,a type of coreless axial flux permanent magnet machine,which has the characteristics of short axial dimension,small volume,light weight,simple and compact structure,high power density.At present,most of the coreless stators are hold together in position with composite material of epoxy resin,which have some problem of immature manufacture technology,difficult Coil positioning,and poor processing precision of winding shape and size,etc.In this paper,the printed circuit board(PCB)technology is introduced into the stator winding production field of the disc-type coreless machine.The stator winding is directly printed on the insulation board of PCB,which simply solves some problem of complex manufacture technology,imprecive positioning of traditional coreless stator,etc.What’s more,because the disc structure of the PCB board is perfectly matched with the axial magnetic circuit structure of the disc-type coreless machine,the axial space can be shorten,and the manufacture cost of the PCB board is low.The manufacture technology is also mature.It analyzes and studies the basic structure,basic principle and basic electromagnetic relationship of disc permanent magnet machine with PCB stator in this paper.First of all,the four basic structures of the machine and the characteristics of the stator and rotor are analyzed.The electromagnetic analysis on the electromotive force(EMF),electromagnetic torque and output power of the motor are performed.At the same time,the design method of the main parameters of the motor is given.The detailed design ideas of the main parameters of the PCB stator aiming at the small low-speed PCB disc-type coreless machine are proposed by Combining with the manufacture requirements of the PCB stator.It provides a clear proposal for the design of pole number,arc coefficient,permanent magnet(PM)thickness and back-iron thickness of rotor in this paper.A three-dimension(3D)finite element analysis(FEA)model of PCB disc machine is established,based on Magnet software.The influence of armature reaction on flux density of air gap is analyzed.According to the application in low speed of motor and the design characteristics of stator and rotor,the active conductor of PCB stator and the PM of rotor are analyzed and optimized.The phase resistance,basic copper loss,winding eddy current loss and output power of the optimized PCB stator are compared and analyzed with the original PCB stator.The advantages of the optimized unequal-width PCB stator in reducing the copper loss of the winding and increasing the output power of the machine are described.At the same time,specifically for the characteristics of a little number of flux linkage of winding coil in the outer end region,the number of flux linkage of the coil in the outer end region is increased by extending the length of the permanent magnet in the radial direction,which can improve the output power of the machine.In this paper,the eddy current loss in the winding,no-load EMF and output power of the machine with the extended PM are compared and analyzed with that of the original PM.The result shows the output power of the machine with extended PM is further improved.Finally,it provides a drawing method for PCB stators in this paper,and the prototype machine is designed and manufactured for no-load,load and temperature rising experiments.Then the experimental datas are compared with the simulation and analytical datas,and the results are in good consistent with each other,which verifies the rationality and effectiveness of the FEA and the analytical method.It provides a reference and practical engineering value for the design of disc permanent magnet machine with PCB stator.