Patent ID: 8476859

Claim:
A motor drive, comprising: an input receiving AC input electrical power from a power source; an output providing AC output electrical power to a motor load; at least one active power converter stage coupled between the input and the output and operative to convert electrical power from a first form to a second form, the at least one active power converter stage comprising: a converter stage input, a converter stage output, and a plurality of switch circuits coupled between the converter stage input and the converter stage output and operative according to a plurality of switching control signals to selectively couple the converter stage input and the converter stage output, with individual switch circuits comprising a switching device including a first power terminal, a second power terminal, and at least one control terminal, and a switch driver operating the at least one control terminal of the switching device according to a corresponding switching control signal to selectively connect or disconnect the first and second power terminals, a plurality of driver supply circuits individually associated with a corresponding switch circuit or a group of switch circuits, with individual driver supply circuits comprising an AC driver supply input operative to receive high frequency AC input current, a DC driver supply output operatively coupled with the corresponding switch circuit or a group of switch circuits to provide DC power to the switch drivers, and an AC-DC converter circuit operative to convert the high frequency AC input current to provide DC output power to the DC driver supply output, and a plurality of current transformers individually having a secondary winding coupled to provide high frequency AC input current to the AC driver supply input of a corresponding one of the plurality of driver supply circuits; a high frequency AC current supply operative to provide a high frequency AC output current; at least one cable coupled with an output of the high frequency AC current supply to conduct the high frequency AC output current, the at least one cable operatively magnetically coupled with cores of the plurality of current transformers to provide primary current to drive the secondary windings of the plurality of current transformers to provide the high frequency AC input current to the plurality of driver supply circuits; and a switch control system operatively coupled with the at least one active power converter stage to provide the plurality of switching control signals to the switch circuits to cause the at least one active power converter stage to convert electrical power from the first form to the second form.