Autotransformer rectifier unit with multiple alternating current level outputs

A method to provide three-phase ac voltages at different output voltage magnitudes based on a three-phase input voltage, the method comprising:

• receiving a three-phase input voltage at a three-phase to two twelve-phase output transformer, the three-phase to two twelve-phase output transformer comprising:
• a plurality of first primary winding groupings, each first primary winding grouping including a plurality of first sub-primary windings coupled in series, wherein each first end of a first primary winding grouping is connected to each of the first end of a plurality of the first primary winding groupings to form a wye configuration and each second end of each of the first primary winding groupings defining an input phase connection that receives a phase of the three-phase input voltage;
• a plurality of second primary winding groupings, each second primary winding grouping including a plurality of second sub-primary windings coupled in series, each second primary winding grouping having a first end and a second end, the first end connected to the first end of the plurality of the first primary winding groupings forming the wye configuration and the second end connected to an output connection of a first twelve phase outputs of the three-phase to two twelve-phase output transformer;
• a plurality of secondary windings, each secondary winding having a first end and a second end with the first end coupled to an output connection of the first twelve phase outputs of the three-phase to two twelve-phase output transformer and the second end connected to a third winding of a plurality of third windings connected between and in series with one of the plurality of first sub-primary windings or connected in series with one of the plurality of second sub-primary windings coupled in series;
• each third winding of the plurality of third windings having a first end and a second end, wherein the first end of a third winding is coupled to a second end of one of the plurality of secondary windings and the second end is connected to a fourth winding of a plurality of fourth windings,
• each fourth winding of the plurality of fourth windings having a first end and a second end, each fourth winding connected between one of the plurality of first sub-primary windings coupled in series or connected between one of the plurality of second sub-primary windings coupled in series, wherein the first end of the fourth winding is connected to a second end of one of the plurality of third windings and an output connection of a second twelve phase outputs of the three-phase to two twelve-phase output transformer and the second end is connected to a second end of a fifth winding of a plurality of fifth windings and to one of the first sub-primary windings or one of the second sub-primary windings;
• each fifth winding of the plurality of fifth windings having a first end connected to an output connection of the second twelve phase outputs of the three-phase to two twelve-phase output transformer and the second end connected to a second end of one of the fourth windings;
• wherein each of the first primary winding groupings, the second primary winding groupings, the secondary windings and the third windings are configured such that an output voltage at each output connection of the first twelve phase outputs of the three-phase to two twelve-phase output transformers is at a sufficiently equivalent voltage of the phase of the three-phase input voltage applied to the input phase connection and the each of the first primary winding groupings, the second primary winding groupings, the secondary windings, the third windings, the fourth windings, and the fifth windings connected to the output connections of the second twelve phase outputs of the three-phase to two twelve-phase output transformer are configured such that an output voltage at each of the output connection of the second twelve phase outputs of the three-phase to two twelve-phase output transformer is at a lower voltage than the phase of the three-phase input voltage applied to the input phase connection;
• enabling each of the second twelve phase outputs of the three-phase to two twelve-phase output transformer to be connected to an input phase of one of four three-phase ac connections for providing power to equipment operatively connected to one of the four three-phase ac connections during operation;
• and
• enabling each output connection of the first twelve phase outputs of the three-phase to two twelve-phase output transformer to be connected to an input connection of a set of rectifier pairs to provide power to the set of rectifier pairs during the operation.

A three-phase to two twelve-phase output transformer comprising:

• a plurality of first primary winding groupings, each first primary winding grouping including a plurality of first sub-primary windings coupled in series, wherein each first end of a first primary winding grouping is connected to each of the first end of a plurality of the first primary winding groupings to form a wye configuration and a second end of each of the first primary winding groupings defines an input phase connection that receives a phase of a three-phase input voltage;
• a plurality of second primary winding groupings, each second primary winding grouping including a plurality of second sub-primary windings coupled in series, each second primary winding grouping having a first end and a second end, the first end connected to the first end of the plurality of the first primary winding groupings forming the wye configuration and the second end connected to an output connection of a first twelve phase outputs of the three-phase to two twelve-phase output transformer;
• a plurality of secondary windings, each secondary winding having a first end and a second end with the first end coupled to an output connection of the first twelve phase outputs of the three-phase to two twelve-phase output transformer and the second end connected to a third winding of a plurality of third windings connected between and in series with one of the plurality of first sub-primary windings or connected in series with one of the plurality of second sub-primary windings coupled in series;
• each third winding of the plurality of third windings having a first end and a second end, wherein the first end of a third winding is coupled to a second end of one of the plurality of secondary windings and the second end is connected to a fourth winding of a plurality of fourth windings,
• each fourth winding of the plurality of fourth windings having a first end and a second end, each fourth winding connected between one of the plurality of first sub-primary windings coupled in series or connected between one of the plurality of second sub-primary windings coupled in series, wherein the first end of the fourth winding is connected to a second end of one of the plurality of third windings and an output connection of a second twelve phase outputs of the three-phase to two twelve-phase output transformer and the second end is connected to a second end of a fifth winding of a plurality of fifth windings and to one of the first sub-primary windings or one of the second sub-primary windings;
• each fifth winding of the plurality of fifth windings having a first end connected to an output connection of the second twelve phase outputs of the three-phase to two twelve-phase output transformer and the second end connected to a second end of one of the fourth windings;
• and
• wherein each of the first primary winding groupings, the second primary winding groupings, the secondary windings and the third windings are configured such that an output voltage at each of the output connection of the first twelve phase outputs of the three-phase to two twelve-phase output transformers is at a sufficiently equivalent voltage of the phase of the three-phase input voltage applied to the input phase connection and the each of the first primary winding groupings, the second primary winding groupings, the secondary windings, the third windings, the fourth windings, and the fifth windings connected to the output connections of the second twelve phase outputs of the three-phase to two twelve-phase output transformer are configured such that an output voltage at each of the output connections of the second twelve phase outputs of the three-phase to two twelve-phase output transformer is at a lower voltage than the three-phase input voltage applied to the input phase connections.