Interaction between the DC and AC side of twelve-pulse converter systems

The twelve-pulse converter plays an increasingly important part in high-power electronics. The authors investigate the conditions under which the ideal twelve-pulse operation can be faulted. The main interest is focused on the DC link frequency changer with three-phase bridge basic circuits. It is shown that under certain circumstances for the ideal twelve-pulse action to be faulted on the AC as well as on the DC side, atypical harmonics for this type of circuitry appear. This investigation is based on computer simulation. The calculations were partly checked by empirical measurement