This paper presents the study of a position sensorless Brushless DC Motor drive. Back emf detection is proposed to avoid the conventional methodology of rotor position sensing. An equivalent mathematical model of a Brushless DC motor is developed to obtain various parameters required for more accurate control of the drive. The analysis of the modelled drive is performed through simulation results at various speed steps suitable for adjustable speed drive. The drive suggested with a PID controller, equivalent mathematical model and Back emf detection provides a quick and efficient steady state performance during speed changes. Hence, due to the advantages of compact size, Quick response and overcoming conventional position sensing-based drawbacks, this drive is very well-suited for adjustable speed applications.
Keywords: Adjustable speed drive, Back emf detection, Brushless DC motor, Mathematical model, Matlab simulation, PID control.
