Sensorless control via intelligent commutation tuning for brushless DC motor

An intelligent sensorless control strategy for a brushless DC motor (BDCM) is presented. The rotor position for making commutation is first roughly estimated by a proposed switching signal generation scheme using motor terminal voltages. Then an intelligent self-tuning strategy is developed to finely adjust the commutation instant for obtaining optimal torque generating capability. This is achieved by a simple but stable self-tuning algorithm to minimise winding currents at any instant. The effect of commutation instant on the BDCM operation capability is observed analytically and intuitively, and, accordingly, the proposed self-tuning strategy is established. The effectiveness of the proposed method is demonstrated experimentally