Patents by Inventor Ramanujam Ramabhadran

Ramanujam Ramabhadran 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).

  • Patent number: 10491096
    Abstract: A power electronics circuit is disclosed that includes a switching circuit comprising a first solid-state device coupled in series with a second solid-state device, with at least the first solid-state device comprising a solid-state switch having a gate terminal. The power electronics circuit also includes a current sense transformer positioned between the first and second solid-state devices and configured to sense a current flowing on a conductive trace connecting the first and second solid-state devices, and a controller coupled to the switching circuit and the current sense transformer so as to be in operable communication therewith. The controller is programmed to receive a current sense signal from the current sense transformer indicative of the current flowing on the conductive trace and modulate a gate voltage to the gate terminal of the first solid-state device based on the received current sense signal, so as to control switching thereof.
    Type: Grant
    Filed: August 22, 2017
    Date of Patent: November 26, 2019
    Assignee: General Electric Company
    Inventors: Ramanujam Ramabhadran, Robert James Thomas, Ahmed Elasser
  • Patent number: 10374591
    Abstract: Systems and methods provided herein relate to a gate drive circuit for controlling operation of a wide bandgap semiconductor switch. The systems and methods receive a control signal and configuring an operation signal configured to activate a wide bandgap switch (WBG switch). A profile of the operation signal being based on electrical characteristics of first and second shaping circuits. The systems and methods further deliver the operation signal to the WBG switch.
    Type: Grant
    Filed: January 3, 2017
    Date of Patent: August 6, 2019
    Assignee: GENERAL ELECTRIC COMPANY
    Inventors: Ramanujam Ramabhadran, Sayan Acharya, Han Peng, Maja Harfman Todorovic, Ahmed Elasser, Robert Thomas
  • Publication number: 20190068045
    Abstract: A power electronics circuit is disclosed that includes a switching circuit comprising a first solid-state device coupled in series with a second solid-state device, with at least the first solid-state device comprising a solid-state switch having a gate terminal. The power electronics circuit also includes a current sense transformer positioned between the first and second solid-state devices and configured to sense a current flowing on a conductive trace connecting the first and second solid-state devices, and a controller coupled to the switching circuit and the current sense transformer so as to be in operable communication therewith. The controller is programmed to receive a current sense signal from the current sense transformer indicative of the current flowing on the conductive trace and modulate a gate voltage to the gate terminal of the first solid-state device based on the received current sense signal, so as to control switching thereof.
    Type: Application
    Filed: August 22, 2017
    Publication date: February 28, 2019
    Inventors: Ramanujam Ramabhadran, Robert James Thomas, Ahmed Elasser
  • Publication number: 20180212512
    Abstract: Systems and methods for providing automatic short circuit protection in an electrical system via a switching device. In some embodiments, the switching device includes a switching transistor that selectively switches between an open position and a closed position based at least in part on a switching control signal, for example, to facilitate converting electrical power with first electrical characteristics output into electrical power with the second electrical characteristics.
    Type: Application
    Filed: January 20, 2017
    Publication date: July 26, 2018
    Inventors: Ravisekhar Nadimpalli Raju, Ramanujam Ramabhadran, Ljubisa Dragoljub Stevanovic, William George Earls
  • Patent number: 10033298
    Abstract: Systems and methods for providing automatic short circuit protection in an electrical system via a switching device. In some embodiments, the switching device includes a switching transistor that selectively switches between an open position and a closed position based at least in part on a switching control signal, for example, to facilitate converting electrical power with first electrical characteristics output into electrical power with the second electrical characteristics.
    Type: Grant
    Filed: January 20, 2017
    Date of Patent: July 24, 2018
    Assignee: GENERAL ELECTRIC COMPANY
    Inventors: Ravisekhar Nadimpalli Raju, Ramanujam Ramabhadran, Ljubisa Dragoljub Stevanovic, William George Earls
  • Publication number: 20180192486
    Abstract: Methods and systems useful in reducing leakage inductance in a flyback transformer. By way of example, a flyback transformer includes a bobbin. The flyback transformer includes primary windings and secondary windings configured to enter a first side of the flyback transformer, to wrap around the bobbin of the flyback transformer to form a bifilar coil or a multifilar coil, and to exit the flyback transformer on the first side of the flyback transformer.
    Type: Application
    Filed: January 5, 2017
    Publication date: July 5, 2018
    Inventors: Shimon Khananshvili, Michael Manelis, Ramanujam Ramabhadran
  • Publication number: 20180068774
    Abstract: A core includes a first layer, a second layer, and a third layer. The first layer has a first surface, a second surface, and a first recessed pattern extending from the second surface of the first layer toward the first surface of the first layer. The second layer has a third surface, a fourth surface, a second recessed pattern extending from the third surface of the second layer toward the fourth surface of the second layer, and a third recessed pattern extending from the fourth surface of the second layer toward the third surface of the second layer. The third layer has a fifth surface, a sixth surface, and a fourth recessed pattern extending from the fifth surface of the third layer toward the sixth surface of the third layer. The second layer is disposed between the first and third layers such that the second surface of the first layer faces the third surface of the second layer and the fourth surface of the second layer faces the fifth surface of the third layer.
    Type: Application
    Filed: September 7, 2016
    Publication date: March 8, 2018
    Inventors: Ruxi Wang, Manoj Ramprasad Shah, Ramanujam Ramabhadran, Yanzhe Yang
  • Patent number: 9887634
    Abstract: A resonant converter includes a primary stage having first and second switches coupled in series, a controller coupled to the first switch and the second switch to control operation thereof, a first transformer comprising a primary coil coupled to a node between the first and second switches, and a resonant inductor coupled to the primary coil of the first transformer. The resonant converter also includes a secondary stage having a second transformer formed of a primary coil coupled to the resonant inductor and a secondary coil comprising first and second coil sections, a third switch coupled to the first coil section of the secondary coil, and a fourth switch coupled to the second coil section of the secondary coil. A switch drive circuit is provided to drive the third and fourth switches for synchronous rectification, with the switch drive circuit comprising a secondary coil of the first transformer.
    Type: Grant
    Filed: July 23, 2015
    Date of Patent: February 6, 2018
    Assignee: General Electric Company
    Inventors: Ramanujam Ramabhadran, Yehuda Daniel Levy, Xu She
  • Patent number: 9853555
    Abstract: A universal power adapter includes a power converter configured to generate an output power based on a switching frequency of the power converter. The universal power adapter also includes a frequency controller operatively coupled to the power converter and configured to control the switching frequency of the power converter. The universal power adapter further includes a switch capacitor circuit having a plurality of capacitive elements, operatively coupled to the power converter. The switch capacitor circuit is configured to switch between the plurality of capacitive elements. The universal power adapter also includes a capacitance controller operatively coupled to the switch capacitor circuit and configured to control the switch capacitor circuit to control switching between the plurality of capacitive elements to maintain a control parameter within a threshold range of.
    Type: Grant
    Filed: September 17, 2015
    Date of Patent: December 26, 2017
    Assignee: General Electric Company
    Inventors: Ramanujam Ramabhadran, Han Peng, Yehuda Daniel Levy, John Stanley Glaser
  • Patent number: 9787303
    Abstract: There are provided a driver circuit, a method of driving a power switch, and a ballast circuit. For example, there is provided a driver circuit configured to receive a control signal and operate a power switch. The driver circuit includes a first switch, a second switch, and a capacitor coupled to control terminals of the first and second switches. The driver circuit further includes a first diode coupled to a first bias terminal of the driver circuit and to the capacitor. Furthermore, the driver circuit includes a second diode coupled to a second bias terminal of the driver circuit and to a terminal of the power switch.
    Type: Grant
    Filed: December 3, 2015
    Date of Patent: October 10, 2017
    Assignee: GENERAL ELECTRIC COMPANY
    Inventors: Yehuda Daniel Levy, Ramanujam Ramabhadran
  • Publication number: 20170290114
    Abstract: An illumination device is provided. The illumination device includes a light emitting source and a clamped series resonant converter (CSRC) coupled thereto. The CSRC includes a first rectifier to generate a direct current (DC) using an alternating current (AC) voltage. The CSRC further includes an inverter having a switching leg including a plurality of switches coupled in series and a diode leg having a plurality of diodes coupled in series. The diode leg is coupled in parallel with the switching leg. Furthermore, the inverter includes an inductor coupled to the switching leg and a capacitor coupled to the diode leg. The CSRC also includes a transformer coupled to the inverter, where a voltage developed across a primary winding of the transformer causes automatic power factor correction by drawing an input current flowing through the CSRC that is proportional to the AC voltage.
    Type: Application
    Filed: June 21, 2017
    Publication date: October 5, 2017
    Inventors: John Stanley GLASER, Ramanujam Ramabhadran
  • Patent number: 9748844
    Abstract: An electronic device includes a controller configured to regulate one or more voltages or currents of a power converter. The controller is configured to receive an input voltage of the power converter, determine whether the power converter is operating in a first mode of operation or a second mode of operation based at least in part on the input voltage, generate a multiplier reference signal for the power converter based on whether the power converter is operating in the first mode of operation or the second mode of operation, and adjust an input current of the power converter based at least in part on the multiplier reference signal. Adjusting the input current includes correcting the input current to be substantially identical in form to the input voltage.
    Type: Grant
    Filed: December 18, 2015
    Date of Patent: August 29, 2017
    Assignee: General Electric Company
    Inventors: Ramanujam Ramabhadran, Jeffrey Joseph Nasadoski, Yehuda Daniel Levy, Shimon Khananshvili, Pradeep Vijayan, Bruce Richard Roberts
  • Publication number: 20170179829
    Abstract: An electronic device includes a controller configured to regulate one or more voltages or currents of a power converter. The controller is configured to receive an input voltage of the power converter, determine whether the power converter is operating in a first mode of operation or a second mode of operation based at least in part on the input voltage, generate a multiplier reference signal for the power converter based on whether the power converter is operating in the first mode of operation or the second mode of operation, and adjust an input current of the power converter based at least in part on the multiplier reference signal. Adjusting the input current includes correcting the input current to be substantially identical in form to the input voltage.
    Type: Application
    Filed: December 18, 2015
    Publication date: June 22, 2017
    Inventors: Ramanujam Ramabhadran, Jeffrey Joseph Nasadoski, Yehuda Daniel Levy, Shimon Khananshvili, Pradeep Vijayan, Bruce Richard Roberts
  • Publication number: 20170163257
    Abstract: There are provided a driver circuit, a method of driving a power switch, and a ballast circuit. For example, there is provided a driver circuit configured to receive a control signal and operate a power switch. The driver circuit includes a first switch, a second switch, and a capacitor coupled to control terminals of the first and second switches. The driver circuit further includes a first diode coupled to a first bias terminal of the driver circuit and to the capacitor. Furthermore, the driver circuit includes a second diode coupled to a second bias terminal of the driver circuit and to a terminal of the power switch.
    Type: Application
    Filed: December 3, 2015
    Publication date: June 8, 2017
    Inventors: Yehuda Daniel LEVY, Ramanujam RAMABHADRAN
  • Publication number: 20170139582
    Abstract: A method for controlling an illumination device is provided. The method includes obtaining an image of an illumination device, thereby capturing an illumination pattern generated by the illumination device based on a visible light communication technique. The method also includes identifying the illumination pattern based on the image. The method further includes determining a unique identification code of the illumination device based on the illumination pattern. The method also includes representing the illumination device in a computer-generated image based on the unique identification code. The method further includes controlling the illumination device using a physical gesture-based graphic user interface.
    Type: Application
    Filed: November 13, 2015
    Publication date: May 18, 2017
    Inventors: Danijel Maricic, Stanislava Soro, Ramanujam Ramabhadran
  • Patent number: 9641063
    Abstract: A power factor controller (PFC) for an electrical load such as LED lighting includes a power factor correcting converter for generating a sinusoidal input current. The PFC further includes a programmable controller for estimating a phase shifted multiplier. A current regulator generates a desired PFC current in response to an input voltage, an output load and the phase shifted and subsequently blanked multiplier. The electrical load operates in response to the sinusoidal input current based at least partially on the desired PFC current.
    Type: Grant
    Filed: January 27, 2014
    Date of Patent: May 2, 2017
    Assignee: General Electric Company
    Inventors: Ramanujam Ramabhadran, Gang Yao, Bruce Richard Roberts, Jeffrey Joseph Nasadoski
  • Publication number: 20170085186
    Abstract: A universal power adapter includes a power converter configured to generate an output power based on a switching frequency of the power converter. The universal power adapter also includes a frequency controller operatively coupled to the power converter and configured to control the switching frequency of the power converter. The universal power adapter further includes a switch capacitor circuit having a plurality of capacitive elements, operatively coupled to the power converter. The switch capacitor circuit is configured to switch between the plurality of capacitive elements. The universal power adapter also includes a capacitance controller operatively coupled to the switch capacitor circuit and configured to control the switch capacitor circuit to control switching between the plurality of capacitive elements to maintain a control parameter within a threshold range of.
    Type: Application
    Filed: September 17, 2015
    Publication date: March 23, 2017
    Inventors: Ramanujam Ramabhadran, Han Peng, Yehuda Daniel Levy, John Stanley Glaser
  • Patent number: 9585207
    Abstract: A light emitting diode (LED) driver includes an inverter for converting a DC input signal to a pulsating signal. A multiple output multi-resonant converter generates a first LED string current in response to the pulsating signal, and also generates a second LED string current in response to the pulsating signal. A transistor that may be a FET or BJT operating in its linear region regulates the second LED string current independent of the first LED string current without sacrificing efficiency of the overall power train.
    Type: Grant
    Filed: July 11, 2014
    Date of Patent: February 28, 2017
    Assignee: General Electric Company
    Inventors: Ramanujam Ramabhadran, Gang Yao
  • Publication number: 20170025965
    Abstract: A resonant converter includes a primary stage having first and second switches coupled in series, a controller coupled to the first switch and the second switch to control operation thereof, a first transformer comprising a primary coil coupled to a node between the first and second switches, and a resonant inductor coupled to the primary coil of the first transformer. The resonant converter also includes a secondary stage having a second transformer formed of a primary coil coupled to the resonant inductor and a secondary coil comprising first and second coil sections, a third switch coupled to the first coil section of the secondary coil, and a fourth switch coupled to the second coil section of the secondary coil. A switch drive circuit is provided to drive the third and fourth switches for synchronous rectification, with the switch drive circuit comprising a secondary coil of the first transformer.
    Type: Application
    Filed: July 23, 2015
    Publication date: January 26, 2017
    Inventors: Ramanujam Ramabhadran, Yehuda Daniel Levy, Xu She
  • Patent number: 9537080
    Abstract: A system for driving a piezoelectric load includes a direct current (DC) voltage source and a bi-directional DC-to-DC converter having a primary side coupled to the DC voltage source and a secondary side and comprising a control input configured to receive a first control signal configured to control conversion of a first voltage on the primary side of the bi-directional DC-to-DC converter to a second voltage on the secondary side of the bi-directional DC-to-DC converter. The driver system also includes a capacitor coupled to the secondary side of the bi-directional DC-to-DC converter and configured to remove a DC offset of the second voltage and includes a reactive load having a first terminal coupled to the capacitor and a second terminal coupled to the secondary side of the bi-directional DC-to-DC converter.
    Type: Grant
    Filed: December 30, 2014
    Date of Patent: January 3, 2017
    Assignee: General Electric Company
    Inventors: Ramanujam Ramabhadran, John Stanley Glaser