Research On Torque Ripple Suppression Of Brushless DC Motor Based On Buck-Boost Topology And Kalman Filter

Brushless DC motor has many advantages,such as small volume,fast response speed and high power density.It has been widely applied in modern society.The torque ripple problem of Brushless DC motor will reduce the service life and stability of the system.Starting with improving the DC bus voltage and improving the precision of motor speed,this paper studies the method of reducing the torque ripple,which is of great significance to the improvement of the motor control performance.First,the working principle of the motor is analyzed,and the mathematical model of the motor running system is deduced.By analyzing the generation mechanism of torque ripple,a method based on Buck-Boost topology is proposed to improve the DC bus voltage and the sensorless speed observation method based on Kalman filter.Secondly,on the basis of the analysis of the principle of Buck-Boost converter,the control strategy of Buck-Boost converter is studied,and a multi-loops control strategy based on fuzzy PI is proposed.The model of motor system based on fuzzy PI multi-loops control is simulated,the effectiveness of the method is verified by improving the DC bus voltage and reducing the torque ripple of the motor.Thirdly,in order to achieve accurate estimation of the speed of sensorless,Kalman filtering algorithm is adopted.The state equation of BLDC motor based on Extended Kalman(EKF)is derived.Aiming at the lack of accuracy in the EKF algorithm,using the Unscented Kalman filter(UKF)to improve the speed estimation accuracy in sensorless mode.The insensitivity of UKF algorithm to motor parameters is proposed to improve the accuracy of motor speed estimation when the motor may be disturbed by various reasons in operation.Three cases of resistance disturbance,inductance disturbance and both simultaneous disturbance are compared and analyzed.The simulation results show that the UKF algorithm is robust to the parameter disturbance and greatly improves the reliability of the speed estimation.Finally,based on the principle of Buck-Boost converter and UKF algorithm,using TMS320F2812 DSP chip,the related hardware circuit and system software are designed,and the experimental platform is built.The experimental results verify the effectiveness of the designed system.