Passive Waveshaping Techniques in AC-DC Converters Feeding Vector Controlled Induction Motor Drives

This paper deals with passive wave shaping techniques in single-phase ac-dc converters feeding three-phase vector controlled induction motor drives (VCIMD's) for improving power quality at the point of common coupling (PCC). Different passive wave shaping schemes are presented for reducing harmonics into single-phase ac mains upto the desired levels as per the system constraints. A pulse multiplication scheme consisting of a dc inductor along with two diodes is used for effective harmonic reduction. The effect of load variation on VCIMD is also studied and it is shown that the proposed passive wave shapers are capable of meeting the IEEE Standard 519 limits along with the power factor improvement close to unity in the wide operating range of the drive. A comparison is made of various power quality indices in different passive wave shapers used in single-phase ac-dc converters feeding three-phase VCIMD.