Simulation of BLDC Motor Drive for Ceiling Fan Application

The future of ceiling fans is not with conventional induction motor but with BLDC motor. Brushless Direct Current (BLDC) motor consumes 50 percent less electrical energy compared to IM and eliminates commutation losses. The relationship between current to torque and voltage to rpm of BLDC motor is linear which is favorable for ceiling fan application. This paper deals with implementing BLDC motor for ceiling fan application owing to its advantages over IM. Speed controllability through various ranges is the most salient feature of BLDC motor. This feature is crucial for the ceiling fan application. For sensorless BLDC motor operation in order to detect rotor position, back emf detection method is used. The proposed method for position sensorless BLDC drive is carried out by sensing back electromotive force (back EMF) zero crossing from the terminal voltages. The proposed method uses difference of line voltages measured at the terminals of the motor. An amplified version of the appropriate back emf at its zero crossing is provided by the difference of line voltages. We have demonstrated the proposed method through simulation results.