Reducing torque ripple of BLDC motor by integrating DC-DC converter with three-level neutral-point-clamped inverter

Abstract

Purpose This paper presents a novel circuit topology based on a three-level neutral-point-clamped (NPC) inverter and a super-lift Luo-converter for minimizing torque ripple in a brushless DC motor (BLDCM) drive system. In the BLDCM, the stator winding inductance generates current ripple, distort the rectangular current shape, which produces the torque ripples. In addition, the torque ripple generates vibration, speed ripple and prevents the use of BLDCM in high-precision servo drive systems Design/methodology/approach Torque ripple can be mitigated by using the three-level NPC inverter, which applies half of dc-link voltage across the BLDCM terminals and this reduces the torque ripple during non-commutation period. The commutation torque ripple is reduced by employing the super-lift Luo-converter at the input of the three-level NPC inverter, which lifts the dc-link voltage to the desired value depending upon the BLDCM speed. Simulations and experimental results show that the proposed circuit topology is an attractive option to reduce the torque ripple significantly. Findings Experimental results show that the proposed topology can reduces the torque ripple significantly at higher speed, and operates with lower power losses than the two-level inverter-fed BLDCM drive system at higher switching frequency. Originality/value This paper has proposed a novel topology using a super-lift Luo-converter and a three-level NPC inverter to address the torque ripple issue in BLDCM drive system.