Harmonic Reduction Methods at DC Link of Series-Connected Multi-Pulse Rectifiers: A Review

Series-connected multipulse rectifiers (MPRs) are used to provide high-quality electric power for high-voltage and high-power occasions. Due to conventional MPRs have limited harmonic reduction ability that cannot fulfill the related harmonic standard, some effective dc side harmonic reduction methods have been proposed to further improve power quality of the MPRs. This article gives a comprehensive review on dc link harmonic reduction methods of series-connected MPRs. Passive and active harmonic reduction mechanisms are respectively analyzed based on two typical topologies, which are theoretical foundations for understanding and constructing novel harmonic reduction circuits (HRCs). Some useful dc side HRCs are presented and compared from aspects of their performances, complexity of the overall structure, magnetic device capacity and power losses, etc. The necessary simulation results are given to verify and compare the effectiveness of some involved harmonic reduction methods. Based on these topologies, the advantages, drawbacks and future trends of the passive or active methods are concluded; besides, the hybrid harmonic reduction methods are also considered. This article aims to provide useful guidance for the researches of harmonic elimination and multipulse rectification technology.