Performance Analysis of Buck-Boost and SEPIC Converter for Commutation Torque Ripple Minimization in BLDC Motors

This paper discusses comparative analysis of Buck-Boost and SEPIC (Single Ended Primary Inductance) converters used in DC link voltage control technique to reduce torque ripple in Brushless Direct Current Motors (BLDCM). The aim of this study is to prove the efficiency of the aforementioned two converters, which have been adopted in many studies to reduce torque ripples caused by commutation, on the same motor parameters. Although BLDCM has many advantages, ripples in the generated torque have limited the use of these motors in applications requiring precise speed and torque. In this study, BLDCM was analyzed exhaustive mathematically and electrically and the problem that caused commutation torque ripples was explained in detail. The DC link voltage control has been proposed to suppressing torque ripples in the BLDCM. In addition, the link voltages required for reducing the torque ripples were obtained separately via both the Buck-Boost and the SEPIC converters. These converter topologies are examined under certain speed and torque conditions and the results were compared. When the results are evaluated together, it was observed that both converters performed the very closely performance each other. However, the Buck-Boost converter produced the desired voltage levels with less oscillation than the SEPIC converter.