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US 8,476,859 B2Granted
DC power for SGCT devices using a high frequency current loop with multiple current transformers
AssigneeRockwell Automation Technologies, Inc.
InventorsAngelo Bortolus, Bin Wu, Zhongyuan Cheng, Jahangir Afsharian, Navid Zargari, Vijay Khatri
Life of this patent
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Abstract
Motor drives and switch driver power systems are presented in which high frequency AC current (IHF) is provided through one or more cables (202) magnetically coupled with local driver current transformers (240), and the transformer secondary currents are converted to provide DC power to switch drivers of an active power converter stage (110a, 110b) in the motor drive.
Claims20
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.
9 more elements
A switch driver power supply system for providing isolated power to actuate switching devices of an active power converter stage of a motor drive, the switch driver power supply system comprising:
- a plurality of driver supply circuits individually associated with a corresponding switch circuit or a group of switch circuits of the active power converter stage;
- 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 to provide DC power to the corresponding switch circuit or a group of switch circuits, each switch circuit including a switch driver circuit powered by the driver supply output to selectively actuate a corresponding switching device, 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;
- 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;
- and
- 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.
6 more elements
A switch driver power supply system for providing isolated power to actuate switching devices of an active power converter stage of a motor drive, the switch driver power supply system comprising:
- a plurality of driver supply circuits individually associated with a corresponding switch circuit or a group of switch circuits of the active power converter stage;
- 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 to provide DC power to the corresponding switch circuit or a group of switch circuits, 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;
- 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;
- and
- 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,
- where the high frequency current supply comprises:
- a DC-AC converter operative to provide the high frequency AC output current to the at least one cable;
- and
- a diagnostic circuit operative to sense at least one electrical condition of the high frequency AC current supply and to selectively provide a diagnostic output signal or value to the switch Control system, the diagnostic output signal or value being indicative of an adverse electrical condition of the high frequency AC current supply.
10 more elements
A method for converting electrical power in a motor drive, the method comprising:
- providing high frequency AC current to at least one cable magnetically coupled with cores of a plurality of current transformers to provide primary current to drive secondary windings of the plurality of current transformers;
- converting secondary current from the secondary windings of the plurality of current transformers to provide isolated DC power;
- powering switch drivers of a plurality of switch circuits of an active power converter stage of the motor drive using the isolated DC power;
- and
- selectively activating switch control terminals of the plurality of switch circuits using the corresponding switch driver to convert electrical power from a first form to a second form.
2 more elements
Dependencies are inferred from the claim text.