Circuit arrangement for uniform current division in the parallel connection of partial-rectifier groups

摘要

The present invention relates to a circuit arrangement for uniform current division in the parallel connection of partial-rectifier groups for supplying direct current tracks, in which the quasi 12-pulse operation is achieved by the parallel connection of two transformers and two partial rectifiers. Different transformer impedances result in current unbalances and power supply harmonics result in different commutation instants in the partial rectifiers. According to the invention, these disadvantages are avoided or greatly reduced by the fact that there is arranged in series with the transformers (T1, T2), for each phase of the feeding power supply, a current-dividing inductor (coil) (a, b, c), all of which inductors have at least one winding (a1 and a2, b1 and b2, c1 and c2) for each partial-rectifier group, the in-phase currents from the partial-rectifier groups flowing through each of these windings. Each current-dividing inductor (a, b, c) can have a third winding (a3, b3, c3), to which a two-terminal network (Z) is connected, as a result of which the commutation instants are influenced to the extent of advancing their equalisation. With the aid of the current-dividing inductors, uniform current division can also be achieved between two parallel-connected partial-rectifier groups which transmit different levels of power. The circuit arrangement according to the invention can be used in all rectifiers which have a plurality of partial-rectifier groups connected in parallel. IMAGE