Torque Ripple Minimization of BLDC motor Drive using DC Link Current Control with Low Pass Compensator

This paper presents a dc link current control technique for BLDC motor which has an ability to reduce commutation torque ripple significantly. As compare to other torque ripple minimization techniques, it does not require torque observer and calculation of commutation time. Torque is regulated by dc link current control loop in both steady and commutation period. Saturation phenomenon of Proportional-Integral (PI) controller in commutation period is analysed which causes a commutation torque ripple. To avoid this saturation, a Modified Pulse Width Modulation (MPWM) technique which eliminates reverse dc link current and Low Pass (LP) compensation in current sensor is used because of which controllability of PI controller can be achieved in commutation period and ripple can be minimized. The study is carried out on BLDC motor with 1500rpm, 5N.m capacity and effectiveness of proposed control method is verified through simulation on MATLAB simulink.