A Buck-Boost Converter with DC Link Voltage Boost for Minimizing Torque Ripple in Brushless DC Motor

Abstract

Buck-boost converter connected in between the input DC source and three phase bridge inverter, used for minimizing the commutation torque ripples in Permanent Magnet Brushless DC Motor is presented in this paper. Torque during the commutation period depends on phase current which is not undergoing commutation, so by controlling it, torque ripple can be minimized. Moreover, a greater DC link voltage is needed during the commutation time period in comparison to the normal conduction period. The Buck-boost converter operates in boost mode in commutation period for stepping up the DC voltage to the inverter. A simple mode switching circuit is employed to amend the output modes of the Buck-boost converter in normal and commutation time intervals. Simulation studies of this topology are carried out in MATLAB/Simulink environment.