Patents by Inventor Ravisekhar Nadimpalli Raju

Ravisekhar Nadimpalli Raju 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: 20180187653
    Abstract: A hybrid power generation system is presented. The system includes a first power generation subsystem including a prime mover driving a generator including a rotor and a stator, one or more first conversion units coupled to at least one of the rotor and the stator, a first direct current (DC) link, and one or more second conversion units coupled to a corresponding one or more first conversion units via the first DC link. The system includes one or more second power generation subsystems coupled to the first power generation subsystem and one or more power conversion subunits including one or more first bridge circuits coupled to a corresponding one or more second bridge circuits via one or more transformers, where at least one of the one or more second power generation subsystems and the first power generation subsystem includes the one or more power conversion subunits.
    Type: Application
    Filed: July 28, 2017
    Publication date: July 5, 2018
    Inventors: Yashomani Y. Kolhatkar, Govardhan Ganireddy, Ravisekhar Nadimpalli Raju, Rajni Kant Burra, Arvind Kumar Tiwari, John Leo Bollenbecker
  • Publication number: 20180187652
    Abstract: Power converters for use in wind turbine systems are included. For instance, a wind turbine system can include a full power generator having a stator and a rotor. The generator is configured to provide a low voltage alternating current power on a stator bus of the wind turbine system. The wind turbine system includes a power converter configured to convert the low voltage alternating current power provided on the stator bus to a medium voltage multiphase alternating current output power suitable for provision to the electrical grid. The power converter includes a plurality of conversion modules, each conversion module comprising a plurality of bridge circuits. Each bridge circuit includes a plurality of silicon carbide switching devices coupled in series. Each conversion module is configured to provide a single phase of the medium voltage multiphase alternating current output power on a line bus of the wind turbine system.
    Type: Application
    Filed: January 5, 2017
    Publication date: July 5, 2018
    Inventors: Robert Gregory Wagoner, Govardhan Ganireddy, Saurabh Shukla, Rajni Kant Burra, Ravisekhar Nadimpalli Raju, Rui Zhou, Rajib Datta, John Leo Bollenbecker
  • Publication number: 20180191280
    Abstract: Power converters for use in wind turbine systems are included. For instance, a wind turbine system can include a wind driven doubly fed induction generator having a stator and a rotor. The stator is configured to provide a medium voltage alternating current power on a stator bus of the wind turbine system. The wind turbine system includes a power converter configured to convert a low voltage alternating current power provided by the rotor to a medium voltage multiphase alternating current output power suitable for provision to an electrical grid. The power converter includes a plurality conversion modules. Each conversion module includes a plurality of bridge circuits. Each bridge circuit includes a plurality of silicon carbide switching devices coupled in series. Each conversion module is configured to provide a single phase of the medium voltage multiphase alternating current output power on a line bus of the wind turbine system.
    Type: Application
    Filed: January 5, 2017
    Publication date: July 5, 2018
    Inventors: Robert Gregory Wagoner, Govardhan Ganireddy, Saurabh Shukla, Rajni Kant Burra, Ravisekhar Nadimpalli Raju, Rui Zhou, Rajib Datta, John Leo Bollenbecker
  • Patent number: 9985550
    Abstract: A method for use in reducing an inductance of a circuit including a commutation loop defined at least in part by a source conductor and a return conductor between a first component and a second component is described. The method includes disposing a conductive inductance reducer within the commutation loop. The conductive inductance reducer includes an electrically conductive material and an insulator.
    Type: Grant
    Filed: December 23, 2014
    Date of Patent: May 29, 2018
    Assignee: GENERAL ELECTRIC COMPANY
    Inventors: Ravisekhar Nadimpalli Raju, Manoj Ramprasad Shah
  • Publication number: 20180123334
    Abstract: An electrical system includes a power electronics system and a bus bar coupled to the power electronic system. The power electronics system includes a switching device configured to selectively connect and disconnect. The bus bar includes a first conductive layer and a second conductive layer. The first conductive layer is disposed directly adjacent a first insulation layer, wherein the first conductive layer is configured to conduct a first polarity of electrical power to, from, or both the power electronics system. The second conductive layer is disposed directly adjacent the first insulation layer, and is configured to conduct a second polarity of electrical power opposite the first polarity to, from, or both the power electronics system. The first conductive layer comprises a first thickness half a second thickness of the second conductive layer.
    Type: Application
    Filed: October 27, 2016
    Publication date: May 3, 2018
    Inventors: Xu She, Rajib Datta, Ravisekhar Nadimpalli Raju, Maja Harfman-Todorovic, Philip Michael Cioffi
  • Publication number: 20180123476
    Abstract: A power module includes an input bus, a switching device, and an output bus. The input bus includes a first coating of a high permeability magnetic conductive material and is configured to receive input direct current (DC) electrical power from an electrical power source. The switching device is electrically coupled to the first input bus, and is configured to selectively connect and disconnect to facilitate converting the input DC electrical power into output alternating current (AC) electrical power. The output bus includes a second coating of the high permeability magnetic conductive material, and is electrically coupled to the first switching device. The output bus is configured to supply the output AC electrical power to an electrical load.
    Type: Application
    Filed: October 27, 2016
    Publication date: May 3, 2018
    Inventors: Michael Joseph Schutten, Fengfeng Tao, Maja Harfman-Todorovic, Ravisekhar Nadimpalli Raju, Philip Michael Cioffi, Ljubisa Dragoljub Stevanovic
  • Patent number: 9837923
    Abstract: A power converter for a power system includes an input ceramic layer, an output ceramic layer, an input stage coupled to the input ceramic layer, an output stage coupled to the output ceramic layer, and a planar transformer coupled between said input stage and said output stage. The input receives a power input and the output stage generates a power output at least partially as a function of the power input. The planar transformer includes an input winding coupled to the input stage and an output winding coupled to the output stage. The input winding has a plurality of input turns and the output winding has a plurality of output turns. The input turns interleave the output turns.
    Type: Grant
    Filed: August 25, 2016
    Date of Patent: December 5, 2017
    Assignee: General Electric Company
    Inventors: Ravisekhar Nadimpalli Raju, Mark Edward Dame, Nathaniel Benedict Hawes
  • Publication number: 20170317604
    Abstract: A power converter for a power system includes an input ceramic layer, an output ceramic layer, an input stage coupled to the input ceramic layer, an output stage coupled to the output ceramic layer, and a planar transformer coupled between said input stage and said output stage. The input receives a power input and the output stage generates a power output at least partially as a function of the power input. The planar transformer includes an input winding coupled to the input stage and an output winding coupled to the output stage. The input winding has a plurality of input turns and the output winding has a plurality of output turns. The input turns interleave the output turns.
    Type: Application
    Filed: August 25, 2016
    Publication date: November 2, 2017
    Inventors: Ravisekhar Nadimpalli Raju, Mark Edward Dame, Nathaniel Benedict Hawes
  • Patent number: 9780643
    Abstract: A power system for a marine ship includes a plurality of protection zones, wherein at least two protection zones are coupled to each other via at least one bus-tie converter. Each of the protection zones includes a plurality of direct current (DC) buses and a plurality of power converters. The bus-tie converter includes at least two converter legs coupled by at least one inductor. Each converter leg includes a first branch connected with a snubber circuit by an intermediate switching device. The first branch includes two outer switching devices and at least one inner switching device connected between the two outer switching devices. The snubber circuit includes a combination of a diode, a resistor and a capacitor. A controller controls the operation of the plurality of power converters and the at least one bus-tie converter.
    Type: Grant
    Filed: July 1, 2015
    Date of Patent: October 3, 2017
    Assignee: General Electric Company
    Inventors: Dong Dong, Ravisekhar Nadimpalli Raju
  • Publication number: 20170279361
    Abstract: A direct current (DC) to DC power converter includes a first converter for converting a first DC bus voltage into a first high frequency AC voltage and a second converter for converting a second high frequency alternating current (AC) voltage into a second DC bus voltage. The DC to DC converter also includes a resonant circuit for coupling the first bus converter and the second bus converter and a controller for providing switching signals to the first converter and the second converter to operate the power converter in a soft switching mode. The resonant circuit includes a high frequency transformer coupled between the first converter and the second converter and an auxiliary converter coupled in series with a first resonant inductor and the high frequency transformer. The resonant circuit further includes second inductor coupled across a first winding of the high frequency transformer. An auxiliary voltage generated by auxiliary converter is added in series with an output voltage of the first converter.
    Type: Application
    Filed: March 25, 2016
    Publication date: September 28, 2017
    Inventor: Ravisekhar Nadimpalli Raju
  • Patent number: 9745038
    Abstract: A power system for a marine ship includes a plurality of protection zones, wherein at least two protection zones are coupled to each other via at least one bus-tie converter. Each of the protection zones includes a plurality of direct current (DC) buses; wherein DC buses which do not have same DC voltage are coupled to each other via at least one DC to DC converter. Furthermore, at least one energy source is coupled to at least one DC bus via a power electronic converter.
    Type: Grant
    Filed: July 11, 2014
    Date of Patent: August 29, 2017
    Assignee: General Electric Company
    Inventors: Rixin Lai, Di Zhang, Dong Dong, Konrad Roman Weeber, Ravisekhar Nadimpalli Raju, Steven Michael Mankevich
  • Patent number: 9667157
    Abstract: A power converter includes a first bus converter for converting a first direct current (DC) bus voltage into a first high frequency alternating current (AC) voltage and a second bus converter for converting a second high frequency AC voltage into a second DC bus voltage. A resonant circuit couples the first bus converter and the second bus converter. Further, a controller provides switching signals to the first bus converter and the second bus converter to operate the power converter in a soft switching mode. The controller includes a voltage detection circuit connected across at least one switching device of the power converter to detect a device voltage across the at least one switching device and a counter to count a number of hard switching detection pulses of the hard switching pulse signal detector.
    Type: Grant
    Filed: April 27, 2016
    Date of Patent: May 30, 2017
    Assignee: General Electric Company
    Inventors: Dong Dong, Luis Jose Garces, Mohammed Agamy, Ravisekhar Nadimpalli Raju, Yan Pan
  • Publication number: 20170110969
    Abstract: A medium voltage direct current (MVDC) collector system for renewable power generation facilities includes at least one renewable energy generation device. The MVDC collector system also includes at least one direct current (DC)-to-DC (DC/DC) power converter coupled to the at least one renewable energy generation device. The at least one DC/DC power converter is configured to shift a switching operation of the DC/DC power converter between full-wave conversion and half-wave conversion. The MVDC collector system further includes at least one controller coupled to the at least one DC/DC power converter. The at least one controller is configured to regulate shifting the switching operation of the at least one DC/DC power converter between full-wave conversion and half-wave conversion.
    Type: Application
    Filed: October 16, 2015
    Publication date: April 20, 2017
    Inventors: Rui Zhou, Luis Jose Garces, Ravisekhar Nadimpalli Raju, Ashraf Said Atalla
  • Publication number: 20170070154
    Abstract: A multi-level DC-DC converter includes an input side to receive a DC power having an input voltage and current, an output side to provide power to a load at a desired output voltage and current, and a plurality of transformer-isolated DC-DC converters connected between the input and output sides, with the transformer-isolated DC-DC converters being connected in series on one side and connected in parallel on another side. Each of the transformer isolated DC-DC converters further includes a power transformer having a primary winding and a secondary winding, and a plurality of switching devices each selectively operable in one of an On state and an Off state. Operating the switching devices in a complementary On state and Off state alternately at a controlled switching frequency provides for engaging the transformer isolated DC-DC converter and operating the switching devices in a simultaneously On state bypasses the transformer isolated DC-DC converter.
    Type: Application
    Filed: November 16, 2016
    Publication date: March 9, 2017
    Inventors: Ravisekhar Nadimpalli Raju, Rajib Datta, Xu She
  • Patent number: 9559611
    Abstract: A power converter is presented. The power converter includes at least one leg, the at least one leg includes a first string, where the first string includes a plurality of controllable semiconductor switches, a first connecting node, and a second connecting node, and where the first string is operatively coupled across a first bus and a second bus. Furthermore, the at least one leg includes a second string operatively coupled to the first string via the first connecting node and the second connecting node, where the second string includes a plurality of switching units. A method for power conversion is also presented.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: January 31, 2017
    Assignee: General Electric Company
    Inventors: Di Zhang, Luis Jose Garces, Rajib Datta, Ravisekhar Nadimpalli Raju
  • Patent number: 9537410
    Abstract: A system and method for series connecting electronic power devices are disclosed. In one embodiment, a switching device system includes a first upper arm electrically coupled to a first lower arm and a second upper arm electrically coupled to a second lower arm. Each of the arms include a plurality of low voltage sub-modules connected in series and each plurality of low voltage sub-modules includes an auxiliary switching device, a series switching device, and a capacitor. Each plurality of low voltage sub-modules is configured to be sequentially switched using the auxiliary switching device and the series switching device separately in the upper arms and the respective lower arms to control change in voltage over time (dV/dt) while selectively blocking a desired high voltage. Further, a capacitor voltage balancing (sorting or rotating) algorithm may be used to actively balance voltage across each plurality of low voltage sub-modules.
    Type: Grant
    Filed: September 10, 2014
    Date of Patent: January 3, 2017
    Assignee: General Electric Company
    Inventors: Rui Zhou, Luis Jose Garces, Ravisekhar Nadimpalli Raju, Rixin Lai, Di Zhang
  • Patent number: 9520798
    Abstract: A multi-level DC-DC converter includes an input side to receive a DC power having an input voltage and current, an output side to provide power to a load at a desired output voltage and current, and a plurality of tranformer-isolated DC-DC converters connected between the input and output sides, with the tranformer-isolated DC-DC converters being connected in series on one side and connected in parallel on another side. Each of the tranformer isolated DC-DC converters further includes a power transformer having a primary winding and a secondary winding, and a plurality of switching devices each selectively operable in one of an On state and an Off state. Operating the switching devices in a complementary On state and Off state alternately at a controlled switching frequency provides for engaging the tranformer isolated DC-DC converter and operating the switching devices in a simultaneously On state bypasses the transformer isolated DC-DC converter.
    Type: Grant
    Filed: August 26, 2014
    Date of Patent: December 13, 2016
    Assignee: General Electric Company
    Inventors: Ravisekhar Nadimpalli Raju, Rajib Datta, Xu She
  • Patent number: 9515565
    Abstract: A hybrid HVDC converter system includes at least one alternating current (AC) conduit, at least one transformer coupled to said at least one AC conduit, and at least one direct current (DC) conduit. The hybrid HVDC converter system also includes at least one capacitor commutated converter (CCC) configured to convert AC voltages and AC currents to a DC voltage and DC current. The at least one CCC is coupled to the at least one AC conduit through the at least one transformer. The hybrid HVDC converter system further includes at least one self-commutated converter (SCC) configured to convert AC voltages and AC currents to a regulated DC voltage and DC current. The at least one SCC includes at least one AC/DC stage and at least one DC/DC stage coupled to the at least one AC/DC stage.
    Type: Grant
    Filed: March 7, 2014
    Date of Patent: December 6, 2016
    Assignee: General Electric Company
    Inventors: Ranjan Kumar Gupta, Luis Jose Garces, Ravisekhar Nadimpalli Raju
  • Patent number: 9431918
    Abstract: A power converter includes at least one leg with a first string including a plurality of controllable semiconductor switches, a first connecting node, and a second connecting node, wherein the first string is operatively coupled across a first bus and a second bus. The at least one leg also includes a second string operatively coupled to the first string via the first connecting node and the second connecting node, wherein the second string includes a plurality of switching units. The first string includes a first branch and a second branch, wherein the second branch is operatively coupled to the first branch via a third connecting node and the third connecting node is coupled to a ground connection.
    Type: Grant
    Filed: July 29, 2013
    Date of Patent: August 30, 2016
    Assignee: General Electric Company
    Inventors: Di Zhang, Luis José Garcés Rivera, Ravisekhar Nadimpalli Raju, Rixin Lai, Andrew Allen Rockhill
  • Patent number: 9378886
    Abstract: A multi-phase electronic power transformer includes a set of primary windings, wherein each primary winding is configured to couple with an input voltage. The transformer includes a pair of primary switching devices that includes a first primary switching device coupled to a first end of each primary winding and a second primary switching device coupled to a second end of each primary winding distinct from the first end of each primary winding. The transformer includes a set of secondary windings, wherein each secondary winding is configured to inductively couple with a respective primary winding and to output a voltage. The transformer includes a pair of secondary switching devices that includes a first secondary switching device coupled to a first end of each secondary winding and a second secondary switching device coupled to a second end of each secondary winding distinct from the first end of the each secondary winding.
    Type: Grant
    Filed: December 22, 2011
    Date of Patent: June 28, 2016
    Assignee: General Electric Company
    Inventor: Ravisekhar Nadimpalli Raju