Sensorless control via intelligent commutation tuning for brushless DC motor

An intelligent sensorless control strategy for 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. Effectiveness of the proposed method is demonstrated experimentally.