Research on 18-pulse rectifier based on a boost star-fork connected autotransformer

An 18-pulse rectifier based on a step-up or step-down autotransformer in star-fork connection is presented. The voltage vector diagram of the autotransformer is given out and the connection of windings is also analyzed. By arrangement the secondly windings properly, the output voltage can be set in a wide range below or above the 3-phase uncontrolled rectifier with a low THD in the input current. Key analysis and results obtained via the Matlab simulation and some experimental results are presented for validation of the presented work.