Torque Control Of Permanent Magnet Brushless DC Motor Based On Output Mode Reconstruction Of Cuk Converte

Due to the advantages of high power density and simple construction,permanent magnet brushless DC motors(PMBLDCM)are widely applied in electric vehicles,aerospace.etc.However,the motor operating performance will be affected by torque ripple.Aiming at the torque ripple caused by the non-ideal back EMF and commutation process of the PMBLDCM,this paper conducts in-depth research on the causes and suppression methods.In this thesis,the mathematical model of PMBLDCM is introduced,and the causes of motor torque ripple under different modulation methods and the corresponding suppression methods are analyzed.In order to simultaneously suppress the torque ripple generated by the non-ideal back EMF during the normal conduction and the commutation stages,a torque control strategy of PMBLDCM based on the output mode reconstruction of Cuk converter is proposed by using the average torque control strategy in this thesis.By analyzing the working principle and different output modes of the Cuk converter,in the normal conduction stage and the commutation stage,it is proposed to use the output "Mode Ⅱ" and "Mode Ⅲ" of the Cuk converter to change the DC bus voltage to realize the smooth operation control of the motor.In the commutation stage in the high-speed range,the Cuk converter works in the output " Mode Ⅲ",which can effectively improve the DC bus voltage and significantly suppressing the commutation torque ripple.In order to ensure that the motor converter works in the high-efficiency region,the Cuk converter is only used in the commutation stage during the high-speed range,and is not used to adjust the speed of the motor.A voltage hysteresis control strategy is proposed to adjust the output voltage of the Cuk converter,and the output voltage of the Cuk converter can reach the reference value with only a few modulation cycles.The proposed control strategy can effectively reduce the torque ripple of the PMBLDCM and improve the efficiency of the motor converter.Through the Simulink simulation and the establishment of the software and hardware experimental control platform,the simulation and experimental analysis of the steady-state and dynamic running process are carried out.The comparative experimental analysis of the efficiency of the motor converter is carried out,which verifies the feasibility and advancement of the control strategy proposed in this thesis.