A neoteric method based on PWM ON PWM scheme with buck converter for torque ripple minimization in BLDC drive

In this paper a detailed analysis on torque ripples of brushless dc drives in both commutation and conduction region is given. A neoteric method for the elimination of torque ripples in BLDC motor by employing PWM_ON_PWM scheme has been introduced by the addition of a buck converter in the entrance of the inverter. PWM_ON_PWM strategy is mainly applied to compensate the commutation torque ripples during commutation period caused by commutation current and it cannot entirely remove the torque ripples that are resulted from current introducing in the turn off phase. Closed loop operation using PWM_ON_PWM scheme with buck converter is used for eliminating the ripples in both conduction and commutation region. The duty cycle of PWM is regulated by using wave function of back EMF and for speed regulation PI controller is used. Simulation results are used for revealing circuit validation.