A Novel Technique to Reduce Harmonics in a Six Pulse Rectifier

Pulse multiplication methods in both parallel and series connected converters are well known to reduce harmonics. A novel technique with fewer thyristors is proposed in this paper to achieve higher pulses. The proposed scheme uses three re-injection thyristors, two re-injection transformers, and an averaging inductor to achieve 18-pulse operation of a 6-pulse rectifier. This technique will reduce the cost and/or complexity for thyristor operation and harmonics filters.