Neutral voltage based Zero-Crossing point detection method for a Sensorless BLDC motor drive

The back EMF based Sensorless methods have gained attention in the BLDC motor drives. In the present work, the Sensorless algorithm is implemented without comparator IC's for extracting the neutral voltage. The methodology for starting the motor and practical issues for extracting the Zero crossing point with direct comparison between phase and neutral voltages has been addressed. The accumulated neutral variable has been utilized for mitigating redundant comparisons in the direct comparison method. The algorithm is implemented in a 32-bit ARM microcontroller. The proposed method is validated in the experimental platform and confirmed the operation of the Sensorless algorithm.