A REVIEW ON CONTROL TECHNIQUES FOR BRUSHLESS DC (BLDC) MOTORS

Abstract — The development in engineering material technology and tremendous improvement in solid state devices and circuits have resulted in the emerge of new types of electric motors like stepper motors, switched reluctance motors and permanent magnet BLDC motors. Brushless DC (BLDC) Motors have increasing popularity and are the latest choice for motor drive applications due to their reliability, higher values of efficiency, compact size, better dynamic response, silent operation and very low maintenance requirements. These motors are more advantageous over other motors like brushed DC motors and induction motors because of their superior speed-torque characteristics, higher speed and absence of arcing. The BLDC motor also has higher delivered torque to size ratio. The above advantages make it appropriate in applications where space and weight are major factors of consideration. These motors can be controlled in either sensor or sensor-less mode, but to reduce the overall cost and size of motor assembly, sensor-less control techniques are generally employed. This paper gives a brief review on the various control techniques employed for BLDC motors. Keywords : Brushless DC (BLDC) motor, Hall-effect sensors, Pulse Width Modulation (PWM), Back EMF, Neural Network, Fuzzy Logic.