INTERFACE ARRANGEMENT BETWEEN AC AND DC SYSTEMS INCLUDING FILTER AT TRANSFORMER NEUTRAL POINT

摘要

The present invention relates to an interface arrangement (20) for coupling between an AC system (S1) and a DC system (S2). The arrangement includes a converter (22) for conversion between AC and DC and having a DC side and an AC side, a transformer (24) having a primary side with primary windings for coupling to the AC system and a secondary side with secondary windings coupled to the converter, where the secondary windings are coupled to ground via a neutral point of the secondary side, and a filter (26) with filter elements set for removing a frequency component of at three times the fundamental frequency of an AC voltage appearing on the AC side of the converter. The filter is connected between the neutral point of the secondary side of the transformer and ground.