Harmonic Reduction and Power Factor Improvement of BLDC Motor Drive System Using a Selective Harmonic Elimination PWM Based Controller

Brushless DC (BLDC) motors offer several advantages over conventional motors such as higher power density, wide range of torque and speed, high torque per watts, high torque to weight ratio, reliability, lower noise and non-requirement of mechanical parts for commutation. They are also being found as an attractive choice in electric vehicular applications. BLDC motors work based on electronic commutation and inherent problems of power electronic circuits like harmonics and switching losses will be significantly affecting the motor performance. In this paper, a control scheme is proposed which aims to reduce the motor current harmonics and their negative effects and also improve the input power factor of the drive system. A DC-DC boost converter with Input Power Factor (IPF) control combined with an Inverter with Selective Harmonic Elimination based PWM and a passive lowpass filter is used to reduce the THD, reduce the harmonic copper loss and improve the overall system performance like torque ripples and input power factor.