Research On Torque Ripple Reduction Strategy Of Axial Field Non - Core Brushless DC Motor

Axial flux brushless DC motor has a compact motor structure, short axial dimension, high power density, high motor efficiency superior and performance, the electric machine has great market prospects in the field of aviation industry and electric vehicles, etc. But the motor’s coreless structure causes the performance of the torque ripple can not meet the requirements, Thus limiting the application of the motor in the above fields. In this paper, we study the problem of the torque ripple in Axial flux brushless DC motor, and put forward the scheme of torque ripple suppression based on direct torque control.In this paper, the development of the Axial flux brushless DC motor is introduced and the research status of the motor torque ripple at home and abroad is introduced. This paper introduces the unique structure of the stator of the brushless DC motor with an axial magnetic field. The working principle of the motor is studied. The mathematical model of the motor is analyzed. In this paper, the model of the Axial flux brushless DC motor is established by using the counter electromotive force and the motor parameters. The model of double closed-loop control system is established and simulation is carried out.Secondly, the reasons for the torque ripple of the motor with no core of the brushless DC motor are analyzed, and the commonly used method of torque ripple suppression is discussed. For the torque ripple caused by the PWM chopper, the PAM control strategy based on BUCK is used to simulate the motor. The simulation results show that the inhibition of a torque ripple can not achieve the purpose of improving the performance of the motor.Then, the direct torque control algorithm is applied to the control system of Axial flux brushless DC motor. The principle of direct torque control is analyzed, and the scheme of the direct torque control system of Axial flux brushless DC motor is designed, and the simulation is carried out. The simulation results show that the direct torque control algorithm can achieve good control effect for Axial flux brushless DC motor.In the end, the direct torque control system of Axial flux brushless DC motor is set up. The hardware part of the system uses a high performance DSP TMS320F28335 master control chip,highly integrated IPM PS21564 for power driven parts. On the basis of detailed analysis of the motor parameters and control requirements, according to the idea of direct torque control algorithm, the software part of the control system is compiled. Experiments are done using the experimental prototype, the results show that the direct torque control system has a good control effect.