IMPROVEMENT OF BACK EMF & MINIMIZATION OF TORQUE RIPPLE OF BLDC MOTOR
In Brushless DC (BLDC) motor minimized the torque ripple with the help of electronically based commutators. When torque ripple is minimizes then copper loss is also minimizes. In this paper, our main aspect to decrease the torque ripples & improved the back emf of brushless dc (BLDC) motor. This paper shows that the torque produced by the BLDC motors with trapezoidal Back EMF is constant under ideal condition. Due to freewheeling torque ripples are produced which is reduced. In this paper rotor position is determined by the Zero Crossing Detection (ZCD) of back emf. Unlike old methods of calculating Back emf of the BLDC by creating a virtual neutral point, a complimentary method is used. This method provides a wide range of speed. A pre conditioning circuit is proposed to rectify the back emf at very low speed. The rotor position can be determined even in stand still condition to minimize the torque ripple and designed to overcome the disadvantages from other torque ripple decrease methods.