Patents by Inventor Raghothama Reddy

Raghothama Reddy has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20140268906
    Abstract: Methods and systems for current sharing using interleaved LLC power converters are described herein. The method provides for current sharing between a first LLC power converter interleaved with a second LLC power converter. The method includes determining an expected output voltage for at least one of the first and second LLC power converters and measuring an output voltage of at least one of the first and second LLC power converters. The method also includes increasing a dead-time of at least one of the first and second LLC power converters when the measured output voltage exceeds the expected output voltage. Finally, the method includes interleaving the first and second LLC power converters, wherein an output current of the first LLC power converter is substantially equal to an output current of the second LLC power converter.
    Type: Application
    Filed: March 12, 2014
    Publication date: September 18, 2014
    Applicant: General Electric Company
    Inventor: RAGHOTHAMA REDDY
  • Publication number: 20140268905
    Abstract: Methods and systems for improving load transient response in LLC converters are provided herein. The method includes coupling a current sensing circuit to an output of the LLC converter, sensing load current of the LLC converter, and increasing a setpoint voltage for a power factor correction (PFC) circuit output based on the sensed load current.
    Type: Application
    Filed: March 5, 2014
    Publication date: September 18, 2014
    Applicant: General Electric Company
    Inventor: RAGHOTHAMA REDDY
  • Publication number: 20140268904
    Abstract: Methods and systems for calibrating an inductor-inductor-capacitor (LLC) resonant converter are provided herein. The method includes calculating input voltage mathematically as a function of at least one of an output voltage, a load current, and tolerances of components of the LLC resonant converter and operating the LLC resonant converter in an open loop mode at a nominal resonant frequency. The method also includes measuring output voltage of the LLC resonant converter and comparing the measured output voltage to the calculated input voltage.
    Type: Application
    Filed: February 25, 2014
    Publication date: September 18, 2014
    Applicant: General Electric Company
    Inventors: RAGHOTHAMA REDDY, Darwin Drake Smith
  • Publication number: 20140247540
    Abstract: A power distribution rack includes a chassis that defines a first slot and a second slot adjacent the first slot. The power distribution rack also includes a plurality of electronics modules including a first module coupled within the first slot and a second module coupled within the second slot. A central bus bar assembly is coupled to the chassis and includes an outer bus bar including a first flange, a second flange, and a first bus plate extending therebetween. The first and second flanges and the first bus plate define a first channel. The bus bar assembly further includes an inner bus bar coupled within the first channel. The inner bus bar includes a third flange, a fourth flange, and a second bus plate extending therebetween. The first and third flanges are coupled to the first module and the second and fourth flanges are coupled to the second module.
    Type: Application
    Filed: December 10, 2013
    Publication date: September 4, 2014
    Applicant: General Electric Company
    Inventors: Michael Clyde Steeves, Khanh Quoc Nguyen, Paul Scott Nessman, Raghothama Reddy
  • Patent number: 8792254
    Abstract: A power converter includes an input stage connected to receive a three phase AC input voltage and to provide multiple DC voltage levels. The power converter also includes an output stage of a plurality of interleaved LLC converters having series-connected inputs coupled to the multiple DC voltage levels and parallel-connected outputs to provide a DC output voltage. Additionally, the power converter includes a balancing circuit interconnected to the input and output stages to provide substantially balanced output currents from the plurality of interleaved LLC converters for the DC output voltage. Methods of manufacturing and operating a power converter are also provided.
    Type: Grant
    Filed: June 28, 2011
    Date of Patent: July 29, 2014
    Assignee: General Electric Company
    Inventor: Raghothama Reddy
  • Patent number: 8743566
    Abstract: A system for increasing parallel rectifier DC power system efficiency. In one embodiment, the system includes: (1) a controller configured to sense and classify a load magnitude change into groups including large load transients and moderate load transients and (2) at least one rectifier coupled to the controller and configured to transition from a stand-by mode to an active mode upon an occurrence of one of a large load transient and a moderate load transient.
    Type: Grant
    Filed: January 26, 2012
    Date of Patent: June 3, 2014
    Assignee: General Electric Company
    Inventors: Raghothama Reddy, Roy J. Davis
  • Patent number: 8681513
    Abstract: A power converter includes an input stage connected to receive an input signal and to provide an intermediate DC voltage, and an output stage having an LLC converter connected to receive the intermediate DC voltage and to provide a DC output voltage. Additionally, the power converter includes a control unit connected to the input and output stages to regulate the DC output voltage and set a target operating parameter of the LLC converter based on controlling the intermediate DC voltage. A method of operating a power converter is also provided.
    Type: Grant
    Filed: June 28, 2011
    Date of Patent: March 25, 2014
    Assignee: General Electric Company
    Inventor: Raghothama Reddy
  • Publication number: 20140062396
    Abstract: A system for use in supplying power to a power storage device. The system includes a charging device that has a plurality of power converters, each of the power converters having an output terminal configured to output current at a predetermined voltage. The system includes a power conduit configured to couple each of the terminals in series to deliver current from the plurality of power converters to the power storage device. The system includes a controller programmed to receive a power storage device voltage signal, determine a charging voltage level based on the power storage device voltage signal, and enable at least one of the plurality of power converters to supply current at the charging voltage level to the power storage device.
    Type: Application
    Filed: September 6, 2012
    Publication date: March 6, 2014
    Inventor: Raghothama Reddy
  • Publication number: 20140036545
    Abstract: A resonant power converter system includes an output load and a rectifier stage that provides a DC output voltage to the output load from an AC intermediate voltage. The resonant power converter system also includes a resonant inverter stage that provides the AC intermediate voltage from a DC input voltage, wherein an inverter gain is controlled by switching between full-bridge and half-bridge topologies based on an external variable of the resonant power converter system. The resonant power converter system further includes a controller that controls the resonant power converter system. Additionally, a method of operating a power converter includes rectifying an AC intermediate voltage to provide a DC output voltage and providing the AC intermediate voltage by inverting a DC input voltage, wherein an inversion gain of the AC intermediate voltage is controlled by switching between full-bridge and half-bridge inversion topologies based on an external variable.
    Type: Application
    Filed: July 31, 2012
    Publication date: February 6, 2014
    Applicant: General Electric Corporation
    Inventor: Raghothama Reddy
  • Publication number: 20130307339
    Abstract: A power converter and a method of operating the same is described, for use in a power conversion system that is capable of receiving power from various sources, including renewable sources, for delivering power to a load. Power type detection circuitry is provided for identifying the type of power source at the input of each power detector, based on attributes of the time-varying power received. The power converter is constructed of a boost stage followed by a galvanically isolated DC-DC converter stage. If a renewable input power source is detected, the boost stage is controlled to operate at a maximum power point, and the DC-DC converter stage is operated in an open loop manner when load exceeds available power at input. The load falls below available input power, the boost stage is controlled to regulate its output voltage and DC-DC converter stage is also placed under closed loop control.
    Type: Application
    Filed: March 5, 2013
    Publication date: November 21, 2013
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Palanivel Subramanium, Raghothama Reddy, Darwin Smith
  • Publication number: 20130307340
    Abstract: A power converter and method of operating the same for use in a power conversion system capable of receiving power from various sources, including renewable sources, for application to a load. Power type detection circuitry is provided for identifying the type of power source at the input of each power detector, based on attributes of the time-varying power received. The power converter is constructed of a boost stage followed by a galvanically isolated DC-DC converter stage. If a renewable input power source is detected, the boost stage is controlled to operate at a maximum power point, and the DC-DC converter stage is operated in an open loop manner. If the AC grid is detected as the input power source, the boost stage is controlled to attain maximum power factor, and the DC-DC converter stage is placed under feedback control of the output voltage. Operating modes are also switched in response to low load demand.
    Type: Application
    Filed: March 6, 2013
    Publication date: November 21, 2013
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Palanivel Subramanium, Raghothama Reddy, Darwin Smith
  • Publication number: 20130308356
    Abstract: Power converter circuitry for converting power from a power source of any one of a number of power source types, and in which arcing at relays in the event of a shutdown is avoided. A shunt circuit is provided in inrush and protection circuitry of the power converter, the circuit including a power field-effect transistor and optionally a series-connected relay. The shunt circuit is controlled to divert current from the main relay in the event of a rectifier fault, allowing the main relay to be opened under reduced or zero current. The field-effect transistor of the shunt circuit can then be safely opened, allowing its series relay to be opened under zero current conditions.
    Type: Application
    Filed: March 5, 2013
    Publication date: November 21, 2013
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Palanivel Subramanium, Raghothama Reddy, Gary Lin
  • Patent number: 8564976
    Abstract: A system is provided having a first LLC power converter and a second LLC power converter. The first LLC power converter comprises a first LLC voltage source. The second LLC power converter also comprises a second LLC voltage source. The first LLC power converter also comprises a first resonant inductor, a first magnetic inductor, and a first resonant capacitor coupled to the first voltage source of the first LLC power converter. The second LLC power converter comprises a second resonant inductor, a second magnetic inductor, and a second resonant capacitor coupled to the second voltage source of the second LLC power converter. The first LLC power converter and the second LLC power converter are both magnetically couplable to a common load. A resonance of the first LLC power converter substantially matches a resonance of the second LLC power converter.
    Type: Grant
    Filed: November 19, 2008
    Date of Patent: October 22, 2013
    Assignee: General Electric Company
    Inventors: Raghothama Reddy, Robert Catalano, Roger Grandchampt
  • Patent number: 8547711
    Abstract: An active snubber circuit for a power converter, a method of operating the same and an inductor inductor capacitor converter incorporating the circuit or the method. In one embodiment, the circuit includes: (1) a series-coupled first capacitor and diode associated with a secondary-side switch in the power converter and coupled to an output thereof and (2) an active snubber circuit switch coupled in parallel with the diode and configured to receive a control signal that closes the active snubber circuit switch during at least a portion of a time during which the secondary-side switch is open.
    Type: Grant
    Filed: November 19, 2010
    Date of Patent: October 1, 2013
    Assignee: General Electric Company
    Inventor: Raghothama Reddy
  • Publication number: 20130003430
    Abstract: A power converter includes an input stage connected to receive an input signal and to provide an intermediate DC voltage, and an output stage having an LLC converter connected to receive the intermediate DC voltage and to provide a DC output voltage. Additionally, the power converter includes a control unit connected to the input and output stages to regulate the DC output voltage and set a target operating parameter of the LLC converter based on controlling the intermediate DC voltage. A method of operating a power converter is also provided.
    Type: Application
    Filed: June 28, 2011
    Publication date: January 3, 2013
    Applicant: Lineage Power Corporation
    Inventor: Raghothama Reddy
  • Publication number: 20130003431
    Abstract: A power converter includes an input stage connected to receive a three phase AC input voltage and to provide multiple DC voltage levels. The power converter also includes an output stage of a plurality of interleaved LLC converters having series-connected inputs coupled to the multiple DC voltage levels and parallel-connected outputs to provide a DC output voltage. Additionally, the power converter includes a balancing circuit interconnected to the input and output stages to provide substantially balanced output currents from the plurality of interleaved LLC converters for the DC output voltage. Methods of manufacturing and operating a power converter are also provided.
    Type: Application
    Filed: June 28, 2011
    Publication date: January 3, 2013
    Inventor: Raghothama Reddy
  • Publication number: 20120294052
    Abstract: The power conversion module includes a power converter coupled to provide a DC output voltage from an input voltage source. The power converter may have primary and secondary stages, and the power converter may also provide a DC output voltage that is electrically isolated from the input voltage source. Additionally, the power conversion module also includes a voltage controller configured to measure a pre-bias value of the output voltage prior to start-up of the power converter and provide a start-up control signal, wherein the start-up control signal corresponds to an initial output voltage that is greater than the pre-bias value of the output voltage. The initial output voltage includes a start-up voltage margin above the pre-bias value and is maintained for a margin hold time. A method of operating a power conversion module is also provided.
    Type: Application
    Filed: May 17, 2012
    Publication date: November 22, 2012
    Applicant: General Electric Co.
    Inventors: Raghothama Reddy, Stephen Guthrie, Subarna Pal
  • Publication number: 20120195081
    Abstract: A system for increasing parallel rectifier DC power system efficiency. In one embodiment, the system includes: (1) a controller configured to sense and classify a load magnitude change into groups including large load transients and moderate load transients and (2) at least one rectifier coupled to the controller and configured to transition from a stand-by mode to an active mode upon an occurrence of one of a large load transient and a moderate load transient.
    Type: Application
    Filed: January 26, 2012
    Publication date: August 2, 2012
    Applicant: Lineage Power Corporation
    Inventors: Raghothama Reddy, Roy J. Davis
  • Publication number: 20120153730
    Abstract: An interleaved LLC converter, a method of operating an LLC converter and a power supply are disclosed herein. In one embodiment, the LLC converter includes: (1) a plurality of LLC power channels, with each of the plurality having an independent power input and (2) a compensation controller configured to actively adjust the independent power inputs to substantially match output voltage and current levels for a given load condition and a common operating frequency of the plurality of LLC power channels.
    Type: Application
    Filed: August 26, 2011
    Publication date: June 21, 2012
    Applicant: Lineage Power Corporation
    Inventors: Rick L. Barnett, Raghothama Reddy
  • Publication number: 20120127762
    Abstract: An active snubber circuit for a power converter, a method of operating the same and an inductor inductor capacitor converter incorporating the circuit or the method. In one embodiment, the circuit includes: (1) a series-coupled first capacitor and diode associated with a secondary-side switch in the power converter and coupled to an output thereof and (2) an active snubber circuit switch coupled in parallel with the diode and configured to receive a control signal that closes the active snubber circuit switch during at least a portion of a time during which the secondary-side switch is open.
    Type: Application
    Filed: November 19, 2010
    Publication date: May 24, 2012
    Applicant: Lineage Power Corporation
    Inventor: Raghothama Reddy