A Novel 28 Pulse Power Electronic AC to DC Converter for Harmonic Mitigation and Energy Storage Integration

In this paper, a novel autotransformer for 28-pulse AC-DC converter configuration is designed, modeled and simulated to feed vector controlled induction motor drive (VCIMD). The proposed autotransformer configuration consists of two paralleled 7-pulse AC-DC converters involving seven-phase shifted uncontrolled diode bridges with pulse doubling circuit. It improves power quality at AC mains and it meets IEEE-519 standard requirements at varying loads. In this paper, we outline a novel method to profile the rectifier output current to be triangular which results in low ac-side harmonics. The novelty in the proposed approach is that we exploit the dc-side filter design to minimize the volt-amperes (VA) rating of the current source used to profile the dc-side rectifier current. Additional benefits of the proposed method include lower VA rating of the dc filter, simple integration of dc energy storage, and effective ac harmonic control even when the initial rectifier current is discontinuous. And also we compare this proposed 28-pulse rectifier performance with the existed 12-pulse rectifier.