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).
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Patent number: 10148122Abstract: A system is provided. The system includes a plurality of uninterruptible power supplies (UPSs), a ring bus, a plurality of chokes, each choke of said plurality of chokes electrically coupled between a respective UPS of said plurality of UPSs and the ring bus, and a plurality of series compensators, each series compensator of the plurality of series compensators electrically coupled between an associated choke of the plurality of chokes and the ring bus.Type: GrantFiled: August 11, 2015Date of Patent: December 4, 2018Assignee: ABB Schweiz AGInventors: Raghothama Reddy, Silvio Colombi, William J. Schmitt, John P. Skliutas
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Patent number: 9991701Abstract: A direct current (DC) power distribution system is provided. The system includes a plurality of DC power sources, a ring bus, and a plurality of power converters. Each DC power source of the plurality of DC power sources is coupled to the ring bus by a respective power converter of the plurality of power converters.Type: GrantFiled: October 15, 2015Date of Patent: June 5, 2018Assignee: General Electric CompanyInventor: Raghothama Reddy
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Patent number: 9746502Abstract: Systems and methods of monitoring a power system power converter are provided herein. The system includes a plurality of parallel-coupled power converters comprising a power converter input and a power converter output, the power converter output configured to be coupled to a load, each power converter of the plurality of parallel-coupled power converters comprising a power converter controller. The power converter controller is configured to compare an output current of a corresponding power converter to a predetermined output current threshold, monitor the output current for a predetermined time duration when the output current is below the predetermined output current threshold, and shut down the corresponding power converter when the output current is below the predetermined output current threshold for the predetermined time duration.Type: GrantFiled: February 5, 2015Date of Patent: August 29, 2017Assignee: GENERAL ELECTRIC COMPANYInventors: Ravi Gautam, Palanivel Subramaniam, Raghothama Reddy
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Patent number: 9660439Abstract: A direct current power (DC) distribution system includes a plurality of DC power sources, a ring bus, a plurality of switch assemblies, and a plurality of passive protection assemblies. Each DC power source is coupled to the ring bus by a respective switch assembly and a respective passive protection assembly.Type: GrantFiled: June 5, 2015Date of Patent: May 23, 2017Assignee: General Electric CompanyInventors: Yashomani Y. Kolhatkar, Rajendra Naik, Viswanathan Kanakasabai, Raghothama Reddy
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Publication number: 20170110877Abstract: A direct current (DC) power distribution system is provided. The system includes a plurality of DC power sources, a ring bus, and a plurality of power converters. Each DC power source of the plurality of DC power sources is coupled to the ring bus by a respective power converter of the plurality of power converters.Type: ApplicationFiled: October 15, 2015Publication date: April 20, 2017Inventor: RAGHOTHAMA REDDY
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Patent number: 9608513Abstract: 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: GrantFiled: March 5, 2014Date of Patent: March 28, 2017Assignee: General Electric CompanyInventor: Raghothama Reddy
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Patent number: 9548670Abstract: 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: GrantFiled: February 25, 2014Date of Patent: January 17, 2017Assignee: General Electric CompanyInventors: Raghothama Reddy, Darwin Drake Smith
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Patent number: 9520790Abstract: 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: GrantFiled: March 12, 2014Date of Patent: December 13, 2016Assignee: General Electric CompanyInventor: Raghothama Reddy
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Publication number: 20160359319Abstract: A direct current power (DC) distribution system includes a plurality of DC power sources, a ring bus, a plurality of switch assemblies, and a plurality of passive protection assemblies. Each DC power source is coupled to the ring bus by a respective switch assembly and a respective passive protection assembly.Type: ApplicationFiled: June 5, 2015Publication date: December 8, 2016Inventors: Yashomani Y. Kolhatkar, Rajendra Naik, Viswanathan Kanakasabai, Raghothama Reddy
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Patent number: 9491895Abstract: 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: GrantFiled: December 10, 2013Date of Patent: November 8, 2016Assignee: General Electric CompanyInventors: Michael Clyde Steeves, Khanh Quoc Nguyen, Paul Scott Nessman, Raghothama Reddy
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Publication number: 20160181864Abstract: A system is provided. The system includes a plurality of uninterruptible power supplies (UPSs), a ring bus, a plurality of chokes, each choke of said plurality of chokes electrically coupled between a respective UPS of said plurality of UPSs and the ring bus, and a plurality of series compensators, each series compensator of the plurality of series compensators electrically coupled between an associated choke of the plurality of chokes and the ring bus.Type: ApplicationFiled: August 11, 2015Publication date: June 23, 2016Inventors: Raghothama Reddy, Silvio Colombi, William J. Schmitt, John P. Skliutas
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Patent number: 9374001Abstract: Methods and systems for improving load transient response in power conversion systems are provided herein. The system includes a primary stage and a secondary stage, an isolation barrier electrically isolating the primary stage and the secondary stage, and a primary stage controller positioned in the primary stage. The primary stage controller is configured to adjust a step-up converter reference voltage based on a load current signal indicative of a load transient. The load current signal is transmitted from the secondary stage.Type: GrantFiled: February 3, 2015Date of Patent: June 21, 2016Assignee: General Electric CompanyInventors: Palanivel Subramaniam, Raghothama Reddy
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Patent number: 9373964Abstract: 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: GrantFiled: March 5, 2013Date of Patent: June 21, 2016Assignee: General Electric CompanyInventors: Palanivel Subramaniam, Raghothama Reddy, Darwin Smith
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Patent number: 9350175Abstract: 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: GrantFiled: March 5, 2013Date of Patent: May 24, 2016Assignee: General Electric CompanyInventors: Palanivel Subramaniam, Raghothama Reddy, Gary Lin
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Publication number: 20160126855Abstract: Systems and methods of monitoring a power system power converter are provided herein. The system includes a plurality of parallel-coupled power converters comprising a power converter input and a power converter output, the power converter output configured to be coupled to a load, each power converter of the plurality of parallel-coupled power converters comprising a power converter controller. The power converter controller is configured to compare an output current of a corresponding power converter to a predetermined output current threshold, monitor the output current for a predetermined time duration when the output current is below the predetermined output current threshold, and shut down the corresponding power converter when the output current is below the predetermined output current threshold for the predetermined time duration.Type: ApplicationFiled: February 5, 2015Publication date: May 5, 2016Inventors: Ravi Gautam, Palanivel Subramaniam, Raghothama Reddy
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Patent number: 9281753Abstract: 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: GrantFiled: July 31, 2012Date of Patent: March 8, 2016Assignee: General Electric CompanyInventor: Raghothama Reddy
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Patent number: 9178359Abstract: 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: GrantFiled: March 6, 2013Date of Patent: November 3, 2015Assignee: General Electric CompanyInventors: Palanivel Subramaniam, Raghothama Reddy, Darwin Smith
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Patent number: 9083242Abstract: 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: GrantFiled: August 26, 2011Date of Patent: July 14, 2015Assignee: General Electric CompanyInventors: Rick L. Barnett, Raghothama Reddy
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Patent number: 9077052Abstract: 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: GrantFiled: September 6, 2012Date of Patent: July 7, 2015Assignee: General Electric CompanyInventor: Raghothama Reddy
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Patent number: 8929106Abstract: 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: GrantFiled: May 17, 2012Date of Patent: January 6, 2015Assignee: General Electric CompanyInventors: Raghothama Reddy, Stephen Guthrie, Subarna Pal