Speed control of sensorless BLDC motor with two side chopping PWM

Abstract

The Brushless Direct Current (BLDC) motors are one of the motor types rapidly gaining popularity. BLDC motors are used in aerospace applications , medical field , industrial automation equipment and instrumentation. As the name implies, BLDC motors do not use brushes for commutation; instead, they are electronically commutated. This paper proposes a new optimized sensorless drive for speed control of BLDC motor, which is based on back -EMF zero crossing detection (ZCD) of only one phase voltage of BLDC motor. This commutation technique of BLDC motor significantly reduces sensing circuits and cost of motor drive. The effectiveness of proposed speed control for sensorless technique is verified through simulation. Two side chopping PWM technique with a PI duty cycle controller is used for speed control. Keywords - BLDC, PI controller, PWM, ZCD, VSI