Patent ID: 8873263

Claim:
A passive AC-DC converter comprising: an autotransformer, wherein said autotransformer comprises: a plurality of first high voltage AC inputs; a plurality of second low voltage AC inputs; a winding topology having a plurality of windings corresponding to each of multiple phases, said plurality of windings configured such that said autotransformer generates an 18-pulse AC input current waveform, said winding topology having a plurality of phase legs, each phase leg comprising a first winding segment having a turn ratio of 1, a second winding segment having a turn ratio of 1.690, a third winding segment having a turn ratio of 4.668, a fourth winding having a turn ratio of 3.926, a fifth winding segment having a turn ratio of 3.433, a sixth winding segment having a turn ratio of 3.572, and a seventh winding segment having a turn ratio of 3.177, for a step down ratio of 0.9; and a set of autotransformer outputs; a bridge rectifier connected to said set of autotransformer outputs; and a DC output from said bridge rectifier.