Commutation Torque Ripple Reduction in Open-end Winding BLDC Motor Drives

This article introduces a two-level torque hysteresis-based direct torque control (DTC) strategy for a dual inverter-fed three-phase BLDC motor drive (BLDCMD) with open-end stator windings, incorporating a commutation torque ripple mitigation technique. The voltage space vectors generated while the inverters operate in 120-degree and 180-degree conduction modes are utilized to implement the DTC. An analysis of the torque ripple indicates that employing three-phase conducting voltage space vectors during the commutation interval in the DTC scheme substantially reduces commutation torque. Furthermore, the proposed method uses a unipolar-based switching scheme for torque control, which decreases dv/dt compared to a bipolar switching scheme. The motor's electromagnetic torque is maximized by utilizing a two-phase conducting voltage space vectors for torque control during the non-commutation interval. The proposed scheme is validated through simulations using MATLAB-Simulink software and experiment on a laboratory prototype.