Torque ripple reduction in brushless DC motor using repetitive control

Brushless DC (BLDC) motors have been widely used in industry. However, one of the main drawbacks of using BLDC motors is the undesirable torque ripple. The torque ripple can cause mechanical vibration, acoustic noise and bearing damage that reduces the lifetime of the machine. This paper proposes a simple repetitive control scheme to attenuate torque ripple of BLDC motors. In this method, the ripple is considered as an undesirable repeated signal that will be minimized by the repetitive control scheme. The control input used in the proposed method is controlled transistors switching using space vector pulse width modulation technique. Simulation results show the proposed repetitive control technique results in the apparent reduction of the torque ripple when compared to a conventional control scheme.