Research On The Mechanism,Design And Characteristics Of Dual-Rotor Slotless Disc Permanent Magnet Motor With Equidirectional Toroidal Winding

Disc(axial flux)permanent magnet motor has great application prospect in direct drive low-speed and high-torque fields,especially the applications which limits the axial length,such as electric vehicles,robots,aerospace,etc.,due to its high torque density,high power density and compact structure.In such application fields,the higher torque density and more smooth operation of direct drive motor are required due to the limits of space,weight and the high requirement of kinematic accuracy.To satisfy the performance requirements of the direct drive motor,in this thesis,an equidirectional toroidal winding dual-rotor slotless disc permanent magnet(EDTW-DRSDPM)motor is proposed,and its working mechanism,electromagnetic design and characteristics are mainly studied based on the comparative analysis of the EDTW-DRSDPM motor and conventional single-layer and double-layer concentrated winding(SLCW,DLCW)DRSDPM motors.The main research contents of this thesis mainly focus on the following aspects:1)Taking SLCW-,DLCW-and EDTW-DRSDPM motors as research objects,the structural differences between the EDTW and conventional concentrated windings(SLCW and DLCW)are analyzed.Based on the electromotive force(EMF),winding magnetomotive force(MMF)of the single side of coils,and the armature reaction fields under different times,the working mechanism of the EDTW-DRSDPM motor is studied.The differences between the EDTW-DRSDPM and the DRSDPM motors with conventional concentrated windings in working mechanism are revealed.2)For different winding structures,the coil factor and size equations of the SLCW-,DLCW-and EDTW-DRSDPM motors are deduced,which lays an important foundation for the electromagnetic design of the EDTW-DRSDPM motor.The key factors causing the difference between the EDTW-DRSDPM and the DRSDPM motors with conventional concentrated windings in size equations are studied,and the size equations of the DRSDPM motors with two kinds of windings are expressed uniformly by introducing conductor factor.On the premise that the electric and magnetic loadings of the SLCW-,DLCW-and EDTWDRSDPM motors are basically the same,the electromagnetic parameters of the three motors are determined.3)The electromagnetic characteristics of the SLCW-,DLCW-and EDTWDRSDPM motors are compared and analyzed based on three-dimensional finite element method(3D-FEM)including air-gap fields,no-load back-EMF,torque,etc.The comparison results validate the superiority of torque density and efficiency of the EDTW-DRSDPM motor and the correctness of the theoretical analysis of the coil factor and size equations.4)The mathematical model of the EDTW-DRSDPM motor is established under the condition that the dual-rotor d-q rotation coordinate systems are overlapped and the rotation speed,rotation direction and loads are the same.Based on id=0 field orient control(FOC)method,the drive-control performances of the EDTW-DRSDPM motor under constant speed variable load condition are studied in MATLAB/Simulink environment.The simulation results verify the correctness of the mathematical model of the EDTW-DRSDPM motor and the effectiveness of the id=0 FOC method.A prototype of the EDTW-DRSDPM motor is manufactured.The machining process and the processing difficulties of such motor are illustrated.The prototype experimental test platform is built and the performances of the EDTW-DRSDPM motor under no-load and load conditions are tested,which validate the electromagnetic characteristics of the EDTWDRSDPM motor including back-EMF,torque,etc.Through the above research contents,the differences between the EDTWDRSDPM and DRSDPM motors with conventional concentrated windings in winding structure,EMF,winding MMF,armature reaction field,coil factor,size equations,etc.are revealed.The performance superiority of high torque density and efficiency of the proposed EDTW-DRSDPM motor compared with DRSDPM motors with conventional concentrated windings is demonstrated.The feasibility of the practical machining of the EDTW-DRSDPM motor is verified.This thesis provides a theoretical basis for the use and design of motors with EDTW structure,and lays an important foundation for the further research of such motors.