Nine-phase transformer

摘要

The invention includes a transformer for converting three-phase AC power to nine-phase AC power. An autotransformer includes three coils, each coil including a plurality of serial windings that together form a polygon. Nine output nodes are provided between adjacent winding pairs, the windings sized and arranged such that adjacent output voltages are separated by 40 degree phase shift and such that output voltage magnitudes are essentially identical. Both step-up and unity gain input node sets are provided wherein, when three phase AC supply lines are linked to the step-up input set the output voltage is stepped up and when the three phase AC supply lines are linked to the unity gain input set the transformer gain is unity. An isolation transformer includes a secondary arranged like the autotransformer configuration described above.