Sensorless BLDC motor Sliding Mode Control for Disturbance Rejection on Hand Held Motor Drive

This research implemented a full sensor-less Sliding Mode Control (SMC) for a three phase Brushless Direct-Current (BLDC) motor for reduction on disturbance during motor operation. Instead of using hall sensors to provide motor speed feedback, this paper utilized the back counter-ElectroMotive Force (EMF), measured in the motor’s control circuitry, and through the zero-crossing characteristic induced from its operation, a full feedback disturbance rejection is implemented for BLDC motor speed regulation. Experimental results compared this SMC control voltage demonstrated a 30% improvement on recovery time, as well as 25% reduction to the maximum disturbance, along with the traditional PI controllers. A full system identification of the motor parameters are also validated rigorously before selection of the SMC parameters. This result brings benefit of a low cost, firmware only efficient BLDC controller algorithm, that is automated in the Embedded system, for disturbance rejection and can be applied to a vast array of products that entails BLDC motors.