Analysis and minimization of ripple components of input current and voltage of PWM inverters

Analysis and minimization of the ripple components of the input current and voltage of three-phase voltage-source pulsewidth modulated (PWM) inverters are presented in this paper. The analytical expressions for the rms values of the input current and voltage ripples as a function of the shape of the PWM reference signal are derived. It is found that the reference signal which produces a minimum ripple in the input voltage varies as a function of the load power factor. It is also found that the rms value of the inverter input current ripple does not depend on the shape of the reference signal. In respect of the inverter input current and voltage ripples, the addition of harmonics other than the third into the sinusoidal reference is neither useful nor necessary. Experimental results are included to verify the derived expressions.