Efficient Sensorless Speed Control Approach using Comparator with Zero Cross Detection for Brushless DC Motor

Brushless DC Motor have used in various sectors like aerospace, manufacturing and home machines owing to its trouble-free construction. The exact information of the rotor position is necessary for better performance of brushless DC motors the need for the rotor angle information in BLDC has been fulfilled by make use of some form of rotor position sensor. In BLDC drives the position sensor contains drawbacks of high cost, electrical connections, mechanical position problems and disadvantage of being intrinsic source of irregularity. These restricted access results in several sensorless techniques in recent years. This paper provides sensorless speed control of Brushless DC motor using comparator with zero cross detection technique. This technique is based on the back EMF sensing and the commutation signals are generated by each zero crossing point of the terminal voltage. The gating signals are attained by switching sequence of BLDC motor and it is done by means of PI controller. The design analysis and simulation of the proposed system is done using MATLAB version 2010b and the simulation results of sensored and sensorless method is compared.