Study On Torque Ripple Minimization Techniques For Brushless DC Motor

Brushless DC Motor(BLDCM)has many advantages compared with other types of motors,such as its high torque density,low noise,high working efficiency,etc.,widely used in the field of CNC machine tools,aviation,aerospace and instrumentation,and household appliances.However,in order to be able to achieve high-performance control of speed and obtain very accurate rotor position information during operation,the brushless DC motor needs to solve the ripple problem of the torque of the brushless DC motor.The influence of this is the biggest.This paper mainly studies the method of suppressing torque ripple in brushless DC motor.Firstly,the basic structure,driving method and working principle of brushless DC motor are analyzed in detail.The mathematical model of differential equation and transfer function of brushless DC motor is established and analyzed,which is the torque ripple suppression method.The research provides a theoretical basis.Secondly,the causes of the torque ripple of the brushless DC motor are analyzed in detail,Then,a current prediction control method that can be used in the full speed range is used to suppress the torque ripple of the motor,and a PID-current prediction control method is built on Matlab/Simulink software.The simulation model of the double-closed loop control system of the brushless DC motor uses the traditional PID control for the outer loop speed loop.The inner loop current loop adopts the current prediction control method.The simulation analysis shows that the current predictive control is better.The torque ripple of the brushless DC motor is suppressed.Then,aiming at the non-linear,strong coupling and multi-variable characteristics of BLDCM,and to reduce the impact of internal and external disturbances of BLDCM and improve the control accuracy of the current loop current controller in the inner loop,an ADRC control strategy is added to the speed loop,which combines with the previous current predictive control.In order to improve the control accuracy,robustness and anti-jamming ability of the system,an ADRC-current predictive control method is proposed.A simulation model of the double closed-loop control system of brushless DC motor based on ADRC-current predictive control is built on Matlab/Simulink software.The simulation results show that this method can better suppress the torque ripple of BLDCM.Finally,the optimal sliding-mode observer-adaptive notch filter-direct torque control method is used to suppress the torque ripple of BLDCM.The direct torque control method is used to control the torque of BLDCM directly.The optimal sliding-mode observer and adaptive filter are added to suppress the main harmonics of the motor system,and a more accurate back-motor is obtained.Potential signal can improve the accuracy of direct torque control and further suppress the torque ripple of BLDCM.The simulation results show that the method is correct.