Impact of PWM and Duty Ratio Control on Voltage for Sic Fed Three Phase BLDC Motor Drive

This paper presents an analysis of phase voltage and dc bus utilization for a three-phase Brushless DC motor (BLDC). Both pulse-amplitude (PAM) and pulse-width modulation (PWM) is employed to control the phase voltage and line current by adjusting the duty cycle. In this paper an analytical expression is derived for six-step-commutation, Bipolar PWM, HPWM-L-ON, and PWM-ON. Through analytical expression and experimentation a comparative analysis has been performed for the aforementioned PWM techniques. Experimental results on a three-phase star-connected Sic-based BLDC drive are provided to substantiate the analysis on phase voltage, and DC bus utilization.