Journal of Electrical & Electronic Systems

A New Approach for Torque Ripple Minimization in Brushless DC Motor Using SEPIC Converter

Abstract

S. Sridhar Krishna and B. Mahesh Kumar

Brushless DC Motors (BLDCM) are widely used in automated industrial applications like Computer Numerical Control (CNC) machinery, aerospace applications and in the field of robotics. But it still suffers from commutation torque ripple, which mainly depends on speed and transient line current in the commutation interval. This work presents a new circuit topology and a DC link voltage control strategy to keep incoming and outgoing phase currents changing at the same rate during commutation. A Single-Ended Primary Inductor Converter (SEPIC) and a switch selection circuit are employed in front of the inverter. The desired commutation voltage is accomplished by the SEPIC converter. The cause of commutation ripple is analyzed, and the way to obtain the desired DC link voltage is introduced in detail. Finally, simulation results show that, compared with the DC-DC converter, the proposed method can obtain the desired voltage much faster and minimize commutation torque ripple more efficiently at both high and low speeds.