Position Sensorless Speed Control of BLDC Motor with Using Back-EMF Method

Brushless DC (BLDC) motors are increasingly being used in a wide range of applications due to their superior characteristics such as reliability, high efficiency, high torque-to-weight ratio, long life and more. These motors use a permanent magnet (PM) rotor and an electronically commutated stator. The voltages of the stator phase windings are controlled by either sensor-based or sensorless methods to produce the correct rotation. Sensor-based control uses external position sensors to provide feedback on the rotor position, while sensorless control estimates the rotor position using algorithms based on the electrical characteristics of the motor. Sensorless control has the advantage of being able to operate in harsh environments and being cost effective. The purpose of this study is to perform sensorless speed control of BLDC motor in simulation environment. The back electromotive force (back-EMF) based method is used to achieve sensorless control and the back-EMFs are obtained by using the created virtual neutral point.