Research On Performance Of Electric Wheel Combined Core Wheel Hub Motor By 3D Multiphysics Simulation

Using wheel hub motors to directly drive is the future development direction of electric vehicles.Compared with the radial magnetic field motors that are mostly used at present,the disc motor has the characteristics of high power density,low speed and high torque,small torque ripple,small axial length,and is very suitable as a hub direct drive motor.In this paper,the design of the motor's structural design,drive performance,loss analysis,and temperature rise are studied around the goal of designing a high-performance,highreliability disk hub motor.According to the size conditions of the inner space and the requirements of cooling the stator,a new type of internal integrated electric wheel is proposed.The suspension system,transmission mechanism,driving motor and brake mechanism are integrated into the wheel,and the parameters of each mechanism are designed.A new type of hub motor with combined iron core is proposed,which solves the installation problem of the heat dissipation device of the motor and improves the power density of the motor.With the aim of designing high driving performance and high reliability wheel motor,the dynamic parameters and structure of the driving motor are designed,and the design basis of the key parameters such as the number matching of the slot pole of the motor and the arrangement of the winding is provided.Based on Maxwell 3D finite element simulation software,a motor model was established to analyze the steady-state magnetic field and transient magnetic field of the motor.First,the three dimensional flux density distribution of the motor is obtained.The magnetic flux density of the motor is not saturated,and the magnetic flux leakage is less.The rationality of the electromagnetic design is verified.Through simulation,the cogging torque,electromagnetic torque and back EMF of the motor are obtained.In order to reduce the torque ripple of the motor,the method of optimizing the number of pole slot number,reducing the width of the stator slot and optimizing the pole arc coefficient is proposed,which can effectively weaken the cogging torque of the motor and improve the reliability of the wheel motor.The heat source of the motor comes from various losses of the motor.The size and distribution of the motor loss will have different effects on the temperature field of the motor and also affect the efficiency of the motor.In this paper,Using Maxwell 3D software,the copper loss,core hysteresis loss and eddy current loss of motor windings under different working conditions are analyzed in detail.The temperature rise of the motor determines the life and reliability of the motor.The air gap between the motor windings and the stator and rotor is reasonably equivalent,and the temperature field is simulated firstly,and the heat transfer coefficient of the motor is calculated.Finite element analysis of steady and transient temperature field is carried out by using Fluent.The steady temperature field distribution and temperature rise curve of hub motor under different working conditions are obtained.The water structure of the motor is designed,and the flow rate of the circulating coolant is calculated,which provides the design basis for the heat dissipation control system of the motor.