Finite Element Simulation Of Permanent Magnet Brushless Motor Based On PCB Winding

This thesis studies a permanent magnet brushless motor based on PCB(Printed Circuit Board)winding,which belongs to coreless axial magnetic field motor.This type of motor has a compact axial structure,whose air gap is planar,and magnetic field is along the axis.It is characterized by low cost,light weight and high power density,and is suitable for the occasion with thin installation requirements.PCB winding,which is printed on PCB,has high smoothness,convenient winding shape design,flexible installation and easy to achieve mass production.PCB winding has a flat shape,which coincides with coreless axial motor.Therefore,it is mostly used in axial magnetic field motor.This paper mainly focuses on the finite element analysis of permanent magnet brushless motor based on PCB winding,including the establishment of finite element model,analysis and optimization of air gap flux density,and joint simulation.Firstly,this thesis introduces the typical structure,winding type and winding shape of disc motor,and makes parametric analysis and winding model analysis based on spiral PCB winding.This design adopts the structure of middle stator and two sides of rotor.PCB winding adopts spiral winding combined with circular and trapezoidal winding,which further reduces the end resistance of winding and winding loss and improves motor performance at the same time.Secondly,the main design parameters of permanent magnet brushless motor with PCB windings are extracted and a three-dimensional model is built in ANSYS MAXWELL3D.The pre-processing and mid-processing of the model building are introduced in detail.So as to improve the simulation accuracy,the 1:1 ratio of the solid motor is realized to build the model.Thirdly,the finite element model of permanent magnet brushless motor based on PCB winding is used to post-process the electromagnetic analysis,including the air gap flux density distribution under different paths of the motor and eddy current loss of windings.The results show that the air gap flux density of N and S cross-arranged permanent magnets is approximately trapezoidal distribution which is lower near the inner diameter and outer diameter in the radial direction.In order to optimize the air gap magnetic field of the motor,Halbach arrays are applied to PCB winding motors.In this paper,Halbach permanent magnet arrays with 90 degree are used.By comparison,the number of poles of the motor is reduced by half,the auxiliary poles are increased,and the leakage between magnetic fields is reduced.At the same time,the magnetic field intensity under the main poles is increased,and the distribution of air gap magnetic density is closer to trapezoidal wave.The optimized permanent magnet motor based on PCB winding is simulated based on MAXWELL,SIMPLORER and SIMULINK.In order to speed up the simulation,the equivalent circuit model of the motor is extracted,and the dynamic response of the motor is observed by PWM control.