Analysis of Double Star Permanent Magnet Synchronous Generators by a General Decoupled d-q Model

The paper proposes a technique to analyze the double star PM synchronous generators by transforming the two 3-phase winding sets into two couples of windings on the d and q axes of the rotor reference frame. The technique introduces improvements with respect to other approaches, as it takes into account the harmonic content of the no-load flux linkages of the armature windings, it applies to a generic angular displacement between the two winding sets and it greatly simplifies the analysis since the two transformed winding sets are decoupled with respect to each other.