Patents by Inventor Sung-Yeul Park

Sung-Yeul Park 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: 9698700
    Abstract: A power converter can be controlled to generate a target output power. The control process may include obtaining a target current reference for the power converter, sensing an output current of the power converter, and determining a difference between the target current reference and the sensed output current. The next switching duty cycle for the next switching period of the switching circuits in the power converter can be derived based on at least the present switching duty cycle of the present switching period, and the difference between the target current reference and the sensed output current. The switching circuits of the power converter can then be switched according to the derived next switching duty cycle in the next switching period.
    Type: Grant
    Filed: March 11, 2015
    Date of Patent: July 4, 2017
    Assignees: DRS Consolidated Controls, Inc., University of Connecticut
    Inventors: Scott Ramsay, Michael Kelley, Matthew Tarca, John Thompson, David Gellis, Thomas Parsons, Sung Yeul Park, Sungmin Park
  • Patent number: 9621063
    Abstract: A power converter can be controlled to generate a target output power based on a reactive power reference and an active power reference. The control process may include monitoring a time-varying power signal (e.g., a power grid voltage signal from a power grid), and filtering the time-varying power signal to derive a filtered sine component of the time-varying power signal and a filtered cosine component of the time-varying power signal. A sine coefficient and cosine coefficient each based on at least the reactive power reference and the active power reference can be determined, and applied to the filtered sine component and filtered cosine component of the time-varying power signal, respectively. A target current reference of the power converter can then be set to include a sum of the current reference sine component and the current reference cosine component.
    Type: Grant
    Filed: March 11, 2015
    Date of Patent: April 11, 2017
    Assignee: DRS Consolidated Controls, Inc.
    Inventors: Scott Ramsay, Michael Kelley, Matthew Tarca, John Thompson, David Gellis, Thomas Parsons, Sung Yeul Park, Sungmin Park
  • Publication number: 20160268917
    Abstract: A power converter can be controlled to generate a target output power. The control process may include obtaining a target current reference for the power converter, sensing an output current of the power converter, and determining a difference between the target current reference and the sensed output current. The next switching duty cycle for the next switching period of the switching circuits in the power converter can be derived based on at least the present switching duty cycle of the present switching period, and the difference between the target current reference and the sensed output current. The switching circuits of the power converter can then be switched according to the derived next switching duty cycle in the next switching period.
    Type: Application
    Filed: March 11, 2015
    Publication date: September 15, 2016
    Inventors: Scott Ramsay, Michael Kelley, Matthew Tarca, John Thompson, David Gellis, Thomas Parsons, Sung Yeul Park, Sungmin Park
  • Publication number: 20160268916
    Abstract: A power converter can be controlled to generate a target output power based on a reactive power reference and an active power reference. The control process may include monitoring a time-varying power signal (e.g., a power grid voltage signal from a power grid), and filtering the time-varying power signal to derive a filtered sine component of the time-varying power signal and a filtered cosine component of the time-varying power signal. A sine coefficient and cosine coefficient each based on at least the reactive power reference and the active power reference can be determined, and applied to the filtered sine component and filtered cosine component of the time-varying power signal, respectively. A target current reference of the power converter can then be set to include a sum of the current reference sine component and the current reference cosine component.
    Type: Application
    Filed: March 11, 2015
    Publication date: September 15, 2016
    Inventors: Scott Ramsay, Michael Kelley, Matthew Tarca, John Thompson, David Gellis, Thomas Parsons, Sung Yeul Park, Sungmin Park
  • Patent number: 8824174
    Abstract: A new current loop control system method is proposed for a single-phase grid-tie power conditioning system that can be used under a standalone or a grid-tie mode. This type of inverter utilizes an inductor-capacitor-inductor (LCL) filter as the interface in between inverter and the utility grid. The first set of inductor-capacitor (LC) can be used in the standalone mode, and the complete LCL can be used for the grid-tie mode. A new admittance compensation technique is proposed for the controller design to avoid low stability margin while maintaining sufficient gain at the fundamental frequency. The proposed current loop controller system and admittance compensation technique have been simulated and tested. Simulation results indicate that without the admittance path compensation, the current loop controller output duty cycle is largely offset by an undesired admittance path. At the initial simulation cycle, the power flow may be erratically fed back to the inverter causing catastrophic failure.
    Type: Grant
    Filed: February 22, 2008
    Date of Patent: September 2, 2014
    Assignee: Virginia Tech Intellectual Properties, Inc.
    Inventors: Jih-Sheng Lai, Sung Yeul Park, Chien-Liang Chen
  • Patent number: 8624541
    Abstract: Regulating the speed of a two-phase switched reluctance machine (TPSRM) rotor includes selecting either a motoring mode or braking mode of operation for the TPSRM, regulating the rotor speed, when the motoring mode is selected, using a control signal cooperatively produced by a speed control feedback loop and a current control feedback loop; and regulating the rotor speed, when the braking mode is selected, using a control signal produced by the current control feedback loop without the cooperation of the speed control feedback loop. The speed control feedback loop uses an established speed control signal and a signal indicative of the rotor's speed to dynamically adjust a first parameter governing the control signal. The current control feedback loop uses an established current control signal and a signal indicative of the current flowing through a stator winding of the TPSRM to dynamically adjust a second parameter governing the control signal.
    Type: Grant
    Filed: May 1, 2012
    Date of Patent: January 7, 2014
    Assignee: Virginia Tech Intellectual Properties, Inc.
    Inventors: Krishnan Ramu, Keunsoo Ha, Sung-Yeul Park
  • Publication number: 20130009589
    Abstract: Regulating the speed of a two-phase switched reluctance machine (TPSRM) rotor includes selecting either a motoring mode or braking mode of operation for the TPSRM, regulating the rotor speed, when the motoring mode is selected, using a control signal cooperatively produced by a speed control feedback loop and a current control feedback loop; and regulating the rotor speed, when the braking mode is selected, using a control signal produced by the current control feedback loop without the cooperation of the speed control feedback loop. The speed control feedback loop uses an established speed control signal and a signal indicative of the rotor's speed to dynamically adjust a first parameter governing the control signal. The current control feedback loop uses an established current control signal and a signal indicative of the current flowing through a stator winding of the TPSRM to dynamically adjust a second parameter governing the control signal.
    Type: Application
    Filed: May 1, 2012
    Publication date: January 10, 2013
    Applicant: Virginia Tech Intellectual Properties, Inc.
    Inventors: Krishnan RAMU, Keunsoo Ha, Sung-Yeul Park
  • Patent number: 8203302
    Abstract: A single controllable switch (509) drive system for regulating the speed of a two-phase switched reluctance machine (TPSRM) (700) rotor may include a speed control feedback loop (970) component that uses an established speed control signal and a signal indicative of the rotor's speed to dynamically adjust a first parameter. And a current control feedback loop (976) component that uses an established current control signal and a signal indicative of the current flowing through a stator winding (505,508) of the TPSRM to dynamically adjust a second parameter.
    Type: Grant
    Filed: October 3, 2005
    Date of Patent: June 19, 2012
    Assignee: Virginia Tech Intellectual Properties, Inc.
    Inventors: Krishnan Ramu, Keunsoo Ha, Sung-Yeul Park
  • Publication number: 20090200980
    Abstract: A single controllable switch (509) drive system for regulating the speed of a two-phase switched reluctance machine (TPSRM) (700) rotor may include a speed control feedback loop (970) component that uses an established speed control signal and a signal indicative of the rotor's speed to dynamically adjust a first parameter. And a current control feedback loop (976) component that uses an established current control signal and a signal indicative of the current flowing through a stator winding (505,508) of the TPSRM to dynamically adjust a second parameter.
    Type: Application
    Filed: October 3, 2005
    Publication date: August 13, 2009
    Applicant: VIRGINIA TECH INTELLECTUAL PROPERTIES, INC.
    Inventors: Krishnan Ramu, Keunsoo Ha, Sung-Yeul Park
  • Publication number: 20080205096
    Abstract: A new current loop control system method is proposed for a single-phase grid-tie power conditioning system that can be used under a standalone or a grid-tie mode. This type of inverter utilizes an inductor-capacitor-inductor (LCL) filter as the interface in between inverter and the utility grid. The first set of inductor-capacitor (LC) can be used in the standalone mode, and the complete LCL can be used for the grid-tie mode. A new admittance compensation technique is proposed for the controller design to avoid low stability margin while maintaining sufficient gain at the fundamental frequency. The proposed current loop controller system and admittance compensation technique have been simulated and tested. Simulation results indicate that without the admittance path compensation, the current loop controller output duty cycle is largely offset by an undesired admittance path. At the initial simulation cycle, the power flow may be erratically fed back to the inverter causing catastrophic failure.
    Type: Application
    Filed: February 22, 2008
    Publication date: August 28, 2008
    Inventors: Jih-Sheng Lai, Sung Yeul Park, Chien-Liang Chen