T-CONNECTED AUTOTRANSFORMER BASED CONVERTER PROVIDING REDUCED RATING FOR RETROFIT APPLICATIONS

摘要

A 72-pulse clean power AC-DC converter, based on a T autotransformer configuration with reduced kilovolt ampere rating and a THD of lower than 3% is presented. The T-Connected autotransformer based 36-pulse converter is obtained via two paralleled 18-pulse AC-DC converters each of them consisting of a 9-phase (9-leg) diode bridge rectifier. To achieve a 72 pulse output, a pulse doubling circuit is applied which, in one embodiment, is a tapped inter-phase transformer. A T-connected autotransformer is utilized to supply the rectifiers.