Line side harmonics of unbalanced AC/DC converter in transient and steady state

Harmonics analysis of AC/DC power converters have been usually investigated for line-commutated rectifiers and in the steady state of the controlled DC motor drive application. In this paper, PWM rectifiers and transient states of the drive, in case of unbalanced supply are included. The mathematical model of complete DC motor drives have been developed and used in the analysis. The results show an increase of individual and total harmonic distortion in case of unbalance. The same is true with transient states, in which harmonics reach high values exceeding harmonic limits stipulated by harmonic limitation standards.