Back-EMF estimation based sensorless control of Brushless DC motor

The brushless direct current motor (BLDC) control is the most important side that should be taken into consideration as BLDC motor is a highly efficient, reliable, and low cost motor used in the industry. The hall effect sensors performance is not reliable in many applications hence the back electromotive force (BEMF) signals can be used for sensorless position and speed control. However, this paper presents a BEMF observer-based sensorless control algorithm with dc bus voltage and terminal current sensor of the motor which is independent of rotor speed. A line-line voltage (VLL) is calculated from dc bus voltage for calculation in BEMF observer. It also guarantees the proper estimation of speed and position for BLDC motor over full speed range. The effectiveness of the BEMF observer-based method is proved using simulation.