Research On Wheel-edge Direct Drive Permanent Disk Motors For Pure Electric Vehicles

The structure of the permanent magnet wheel-edge direct drive automotive powertrain is obviously superior to the centralized drive structure in terms of high transmission efficiency or effective reduction of the space occupied by the vehicle body.Compared with the traditional radial magnetic permanent magnet motor,the axial flux permanent magnet disk motor has higher power density and torque density and better heat dissipation capability.Therefore,this paper is studies the axial magnetic field wheel-edge direct drive permanent magnet disk motor.Firstly,this paper studies the topological structure characteristics of the permanent disk motor.Starting from the expression of motor power and electromagnetic load,the power density and torque density of radial magnetic field and axial magnetic field are compared,and the multipole logarithm is used.The flat motor structure facilitates a significant increase in the torque density of permanent disk motors.By comparing the characteristics of different topological structures of the permanent magnet disk motor,the dual stator single rotor is selected as the topological structure of the wheel-edge direct drive motor.Secondly,from the perspective of automotive dynamics,this paper establishes the power performance index model of pure electric vehicles,and verifies the motor performance parameters according to the requirements of the dynamic characteristics of the wheel-edge driving pure electric vehicles to determine the constant power and constant rotation of the motor.Moment running range.an analytical model for the multi-ring equivalent magnetic circuit is established,and the magnetic fluxes at the teeth and yoke of the double stator of the axial flux structure are calculated.The current density,motor thermal load,and inductance parameters of the double stator winding series and parallel are calculated.The influence of no-load EMF on the motor is analyzed,the no-load EMF is optimized,and the efficiency of the motor in the full-speed range is improved.An electromagnetic program for a dual-stator single-rotor structure permanent disk motor was developed to complete the electromagnetic scheme of a permanent magnet disk motor.Finally,this paper uses three dimensional finite element modeling simulation to model and analyze the motor.The three dimensional state magnetic field of permanent magnet motor with axial magnetic field is analyzed.The characteristics of stator flux density and air gap flux density of axial field permanent magnet motor are studied,and the torque of axial fieldpermanent magnet motor is analyzed.The torque ripple and torque ripple which affect the torque ripple of the motor are analyzed.The torque ripple is reduced by the angular pole,which improves the smoothness of the torque output of the motor.The temperature field simulation of the water.cooled structure of the motor was performed.The temperature rise of the winding and the permanent magnet was analyzed to verify the rationality of the motor thermal load design.