Auto-connected transformer with 40° phase shifting for harmonic elimination

The conventional six-pulse and 12-pulse generate harmonics pollution in the network. In order to reduce the harmonics propagation has proposed the use of other structures that offer a greater flexibility to transit control of energy and a significant harmonics reduction. In this paper, the authors present the design, analysis and experimental set-up of a delta-connected autotransformer-based 18-pulse ac-dc converter with 40° phase shifting to decrease the harmonics pollution in the network side. The simulation results show that autotransformer configuration 18-pulse capable to suppress harmonics of the order less than 18th.n±1. This design gives a better THD current compared with the two configurations, six-pulse and 12-pulse. Moreover, a prototype of the proposed autotransformer-based 18-pulse ac-dc converter is developed and test results are presented to validate the developed design procedure and simulation models of this ac-dc converter.