Torque ripple reduction in BLDC motor based ona PWM technique for open-end winding

The article presents a modulation method for BLDC motors with unconnected windings. This method uses two full bridges (or three 12-switch H-bridges). The useof the described modulation enables reducing the motor current variable and increasing (fourfold in relation to the switching frequency) the motor current ripple frequency. Themost important benefit of using a 12-switch inverter is the twofold reduction of the dc-linkvoltage while maintaining the rated rpm (voltage reduction in comparison to a typical supplymethod). A voltage reduction causes a reduction in losses on semi-conductor elements. Thearticle also demonstrates that the proposed modulation technique significantly shortens thetime of current commutation between windings