Medium voltage power converter formed using low voltage drives

A medium voltage power converter, comprising:

• an input transformer having a primary winding circuit and a plurality of secondary winding circuits, said primary winding circuit being adapted to connect to a multi-phase AC power source, each secondary winding circuit having three phase-shifted outputs each adapted to provide up to approximately 700 VAC;
• a plurality of low voltage drives, each low voltage drive having a plurality of power inputs each of which is operatively connected in phase relationship to a respective one of the three phase-shifted outputs from a respective one of the secondary winding circuits, and a plurality of power outputs operatively connected to a respective one of the power inputs such that each power output is adapted to provide a current substantially in-phase with the respective one power input;
• and
• an output transformer having a plurality of input primary winding circuits, a plurality of output secondary winding circuits and a secondary winding connection arrangement having three phase-shifted outputs, each of the input primary winding circuits having three input primary windings each of which is operatively connected in phase relationship to a respective one of the power outputs of a respective one of the low voltage drives, each output secondary winding circuit having three output secondary windings each of which is operatively connected in phase relationship with a respective one of the input primary windings of a respective one of the input primary winding circuits;
• wherein a first of the output secondary windings of each output secondary winding circuit are connected in series to generate a first of the phase-shifted outputs of the secondary winding connection arrangement, a second of the output secondary windings of each output secondary winding circuit are connected in series to generate a second of the phase-shifted outputs of the secondary winding connection arrangement, and a third of the output secondary windings of each output secondary winding circuit are connected in series to generate a third of the phase-shifted outputs of the secondary winding connection arrangement.

A medium voltage power converter, comprising:

• an input transformer having a primary winding circuit and a plurality of secondary winding circuits, said primary winding circuit being adapted to connect to a multi-phase AC power source, each secondary winding circuit having three phase-shifted outputs each adapted to provide up to approximately 700 VAC;
• a plurality of low voltage drives, each low voltage drive having a plurality of power inputs each of which is operatively connected in phase relationship to a respective one of the three phase-shifted outputs from a respective one of the secondary winding circuits, and a plurality of power outputs operatively connected to a respective one of the power inputs such that each power output is adapted to provide a current substantially in-phase with the respective one power input;
• and
• an output transformer having a plurality of input primary winding circuits, a plurality of output secondary winding circuits and a secondary winding connection arrangement including three phase-shifted outputs, each of the input primary winding circuits having three input primary windings each of which is operatively connected in phase relationship to a respective one of the power outputs of a respective one of the low voltage drives, each output secondary winding circuit having three output secondary windings each of which is operatively connected in phase relationship with a respective one of the input primary windings of a respective one of the input primary winding circuits;
• wherein a first of the output secondary windings of each output secondary winding circuit are connected in parallel to generate a first of the phase-shifted outputs of the secondary winding connection arrangement, a second of the output secondary windings of each output secondary winding circuit are connected in parallel to generate a second of the phase-shifted outputs of the secondary winding connection arrangement, and a third of the output secondary windings of each output secondary winding circuit are connected in parallel to generate a third of the phase-shifted outputs of the secondary winding connection arrangement.