Design And Research Of Permanent Magnet Brushless DC Wheel Motor Based On Optimization Of Cogging Torque

The Permanent Magnet Brushless Direct Current Motor(BLDCM)is widely used in high-performance situation due to its small size,light weight,good speed performance,high efficiency and other advantages.The cogging torque is inherent characteristic of permanent magnet electric motors,which leads to torque ripples,and then will give rise to vibration noise,and insofar,impact the performance of motors.In this paper,the design of the BLDCM is introduced using field-circuit method.Firstly,the thesis introduces the developing status and application of wheel motor.And there is also the discussion on BLDCM and its research status.The research status of cogging torque are also discussed.Moreover,the structure,working principle and mathematical model of BLDCM are given elaborated.Secondly,there is the design of motor body.The design of the electromagnetic scheme is the basis of the design of the motor body.The main electromagnetic parameters such as the permanent magnet material,the electromagnetic load and the pole arc coefficient are determined,based on the established technical requirements and technical parameters,which determine the main structure size of the motor.In consideration of weakening the cogging torque,winding program is chosen as the motor slot coordination scheme.Thirdly,ANSYS Maxwell was used to analyze the motor.In the RMxprt module,the motor calculated by the initial magnetic circuit method is further optimized.The performance of the motor is simulated and analyzed in the Maxwell 2D module with main waveform obtained.Finally,the cogging torque is optimized.The mathematical model of the cogging torque is expounded,and the stator crown assisted slot method and the closed tank structure stator are used to weaken the cogging torque.By taking the split structure,the embodiment of a closed-slot structure is provided.According to the simulation results,the main parts of the motor are drawn and 3D modeled.