Patents by Inventor Yilu Liu

Yilu Liu 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: 11926063
    Abstract: The present invention provides a fractional order sliding mode synchronous control method for a teleoperation system based on an event trigger mechanism. The method comprises: establishing a dynamics model for the teleoperation system by considering external disturbance and parameter uncertainty, selecting a master robot and a slave robot, interactively establishing the teleoperation system through a communication network, determining system parameters of the dynamics model, designing a fractional order nonsingular rapid terminal sliding mode surface equation by utilizing a position tracking error and a fractional order calculus, setting a trigger event condition of information interaction between the master robot and the slave robot, designing a self-adaptive fractional order nonsingular rapid terminal sliding mode controller based on the sliding mode, designing a Lyapunov function to carry out stability analysis, proving the boundedness of a closed-loop state signal of the system.
    Type: Grant
    Filed: December 3, 2021
    Date of Patent: March 12, 2024
    Assignee: Yanshan University
    Inventors: Changchun Hua, Yilu Wang, Yana Yang, Weili Ding, Liuliu Zhang, Shuang Liu, Guanglei Zhao, Wenliang Pei
  • Patent number: 11882889
    Abstract: A system determines the frequency of grid signals corresponding to an electrical grid in real time. The system includes a transient detector that monitors a grid signal from a voltage meter or a current meter connected to the electrical grid. The system produces, in real time and at a sampling rate, a deviation signal indicative of a periodicity of the monitored grid signal. The system determines, over one or more cycles of the monitored grid signal, a measurement signal corresponding to the deviation signal. The system determines a frequency signal that corresponds a frequency estimation of the monitored signal by applying a frequency estimation when values of the measurement signal are less than a deviation threshold and maintaining the frequency signal at a constant value when values of the measured signal equal or exceeds the deviation threshold.
    Type: Grant
    Filed: March 17, 2021
    Date of Patent: January 30, 2024
    Assignee: UT-Battelle, LLC
    Inventors: Lingwei Zhan, Thomas J. King, Jr., Fuhua Li, Yilu Liu, Wenxuan Yao, He Yin, Bailu Xiao
  • Patent number: 11537086
    Abstract: A pulsar based timing synchronization method and system are disclosed. In one example, a method includes receiving, by a pulsar signal receiver device, a pulse signal emitted from one or more celestial objects and processing, by the pulsar signal receiver device, the pulse signal to discipline a local clock to determine an accurate time output. The method also includes generating, by the pulsar signal receiver device, a timing synchronization signal based on the determined accurate time output. The method further includes providing, by the pulsar signal receiver device, the timing synchronization signal to at least one of a local power system device and a timing distribution network server.
    Type: Grant
    Filed: April 29, 2019
    Date of Patent: December 27, 2022
    Assignees: University of Tennessee Research Foundation, UT-Battelle, LLC
    Inventors: Jiecheng Zhao, Yilu Liu, Yong Liu, Peter Louis Fuhr, Tom King, He Yin, Lingwei Zhan, Marissa Morales-Rodriguez, Wenxuan Yao
  • Patent number: 11515702
    Abstract: Methods, systems, and computer readable mediums for protecting and controlling a microgrid with a dynamic boundary are disclosed. One method includes detecting a fault in a microgrid that includes a dynamic point-of-common-coupling (PCC), in response to determining that the microgrid is operating in a grid-connected mode, isolating the fault by tripping a microgrid side smart switch and a grid side smart switch that are located immediately adjacent to the fault, initiating the reclosing of the grid side smart switch, and initiating the reclosing for the microgrid side smart switch via resynchronization if the grid side smart switch is successfully reclosed, and in response to determining that the microgrid is operating in an islanded mode, isolating the fault by tripping a microgrid side smart switch that is located immediately adjacent to the fault, and initiating the reclosing of the microgrid side smart switch.
    Type: Grant
    Filed: January 29, 2020
    Date of Patent: November 29, 2022
    Assignee: University of Tennessee Research Foundation
    Inventors: Fei Wang, Dingrui Li, Yilu Liu, Yiwei Ma, Ishita Ray, Leon M. Tolbert, He Yin, Lin Zhu
  • Patent number: 11372038
    Abstract: A system and methods for monitoring an impact of geomagnetic disturbances (GMDs) or an E3 component of electromagnetic pulses (EMP-E3), involving a transducer generating a transduced signal in response to a magnetic field of a current carrying element of a transmission line. The transduced signal reflects harmonic characteristics of the current carrying element, and is amplified and filtered, then digitally converted. Excessive impact is detected when a threshold condition is met with respect to a total harmonic distortion (THD) and/or a change in THD. The THD can be calculated from amplitudes of harmonic components of interest. The amplitudes can be calculated in various ways, including Fourier transforming the digital signal to locate peaks in the resulting spectral lines, or using a phase sensitive detection algorithm in which the digital signal is multiplied by a phase swept reference signal and then integrated.
    Type: Grant
    Filed: November 11, 2016
    Date of Patent: June 28, 2022
    Assignees: University of Tennessee Research Foundation, UT-BATTELLE, LLC
    Inventors: Wenxuan Yao, Jiecheng Zhao, Yi Cui, Yilu Liu, Thomas J. King
  • Patent number: 11340271
    Abstract: A method includes performing by a processor: receiving a plurality of synchrophasor measurements of a power system signal associated with a time interval from a plurality of phasor measurement units (PMUs), respectively, each of the plurality of synchrophasor measurements including a phase angle, frequency value, and a timestamp associated with the synchrophasor measurement; determining, for each of the plurality of PMUs, a dominant mode frequency of a forced oscillation signal component of the power system signal based on the frequency value and the phase angle; determining, for each of the plurality of PMUs, a mode angle of the forced oscillation signal component at the dominant mode frequency; and determining a geographic forced oscillation source location for a source of the forced oscillation signal component based on the plurality of mode angles associated with each of the plurality of PMUs, respectively, and geographic locations of the plurality of PMUs.
    Type: Grant
    Filed: July 31, 2020
    Date of Patent: May 24, 2022
    Assignee: UNIVERSITY OF TENNESSEE RESEARCH FOUNDATION
    Inventors: Yilu Liu, Weikang Wang, Wenpeng Yu, Chujie Zeng, Lin Zhu
  • Publication number: 20220140648
    Abstract: A method includes injecting a probe signal into a power system; receiving a measurement of an operational parameter of the power system responsive to injecting the probe signal into the power system; generating a transfer function model of the power system based on the measurement of the operational parameter of the power system and the probe signal; and updating at least one control parameter of a Wide Area Damping Controller (WADC) communicatively coupled to the power system based on the transfer function model.
    Type: Application
    Filed: October 30, 2020
    Publication date: May 5, 2022
    Inventors: Ibrahim Abdullah S. ALTARJAMI, Evangelos FARANTATOS, Hossein HOOSHYAR, Yilu LIU, Mahendra PATEL, Huangqing XIAO, Chengwen ZHANG, Yi ZHAO, Lin ZHU
  • Publication number: 20220137112
    Abstract: A method includes performing by a processor: determining a phase angle alignment parameter based on a ratio of a phase angle difference and a frequency difference, the phase angle difference comprising a difference between a first phase angle corresponding to a reference synchronized measurement device (SMD) and a second phase angle corresponding to a follower SMD, the frequency difference comprising a difference between a frequency at which the first and second phase angles are measured and a nominal frequency; receiving a first plurality of synchrophasor measurements of a power system signal from the reference SMD; receiving a second plurality of synchrophasor measurements of the power system signal from the follower SMD, the first plurality of synchrophasor measurements and the second plurality of synchrophasor measurements being offset in time relative to each other by a sampling time shift; and aligning phase angles of the second plurality of synchrophasor measurements with phase angles of the first plur
    Type: Application
    Filed: October 30, 2020
    Publication date: May 5, 2022
    Inventors: Yilu LIU, Wenxuan YAO, He YIN, Wenpeng YU
  • Publication number: 20220140607
    Abstract: A high voltage direct current (HVDC) transmission system comprises a first terminal comprising a first voltage source converter (VSC) having a first and second VSC terminals and a first line commutated converter (LCC) having first and second LCC terminals; a second terminal comprising a second VSC having third and fourth VSC terminals and a second LCC having third and fourth LCC terminals; and a transmission line pair comprising a positive transmission line that couples the first VSC terminal and the first LCC terminal of the first VSC and the first LCC, respectively, to the third VSC terminal and the third LCC terminal of the second VSC and the second LCC, respectively, and a second positive line that couples the second VSC terminal and the second LCC terminal of the first VSC and the first LCC, respectively, to the fourth VSC terminal and the fourth LCC terminal of the second VSC and the second LCC, respectively.
    Type: Application
    Filed: October 30, 2020
    Publication date: May 5, 2022
    Inventors: Yilu LIU, Kaiqi SUN, Huangqing XIAO
  • Patent number: 11320893
    Abstract: An apparatus includes a photovoltaic module and a computation module that is coupled to the photovoltaic module and is configured to receive power therefrom, the computation module being configured to communicate an active message to a controller in response to the computation module transitioning to a power on state and configured to receive a task command from the controller in response to communicating the active message to the controller.
    Type: Grant
    Filed: June 25, 2020
    Date of Patent: May 3, 2022
    Assignees: UNIVERSITY OF TENNESSEE RESEARCH FOUNDATION, DOMINION ENERGY INC.
    Inventors: Yilu Liu, Robert Gardner, Yuru Wu
  • Publication number: 20220034947
    Abstract: A method includes performing by a processor: receiving a plurality of synchrophasor measurements of a power system signal associated with a time interval from a plurality of phasor measurement units (PMUs), respectively, each of the plurality of synchrophasor measurements including a phase angle, frequency value, and a timestamp associated with the synchrophasor measurement; determining, for each of the plurality of PMUs, a dominant mode frequency of a forced oscillation signal component of the power system signal based on the frequency value and the phase angle; determining, for each of the plurality of PMUs, a mode angle of the forced oscillation signal component at the dominant mode frequency; and determining a geographic forced oscillation source location for a source of the forced oscillation signal component based on the plurality of mode angles associated with each of the plurality of PMUs, respectively, and geographic locations of the plurality of PMUs.
    Type: Application
    Filed: July 31, 2020
    Publication date: February 3, 2022
    Inventors: YILU LIU, WEIKANG WANG, WENPENG YU, CHUJIE ZENG, LIN ZHU
  • Patent number: 11209469
    Abstract: A method includes performing by a processor: receiving a plurality of synchrophasor measurements of a power system signal associated with a time interval from a phasor measurement unit (PMU), each of the plurality of synchrophasor measurements including a phase angle, frequency value, and a timestamp associated with the synchrophasor measurement, determining a plurality of relative phase angles based on the plurality of phase angles, determining a correlation coefficient between the plurality of relative phase angles and a plurality of corresponding frequency values of the power system signal, and detecting an error in the plurality of timestamps based on the correlation coefficient; estimating the error in the plurality of timestamps based on the plurality of relative phase angles and the plurality of corresponding frequency values.
    Type: Grant
    Filed: May 21, 2019
    Date of Patent: December 28, 2021
    Assignees: UNIVERSITY OF TENNESSEE RESEARCH FOUNDATION, UT-BATTELLE, LLC
    Inventors: Yilu Liu, Wenpeng Yu, Wenxuan Yao
  • Publication number: 20210328431
    Abstract: A system determines the frequency of grid signals corresponding to an electrical grid in real time. The system includes a transient detector that monitors a grid signal from a voltage meter or a current meter connected to the electrical grid. The system produces, in real time and at a sampling rate, a deviation signal indicative of a periodicity of the monitored grid signal. The system determines, over one or more cycles of the monitored grid signal, a measurement signal corresponding to the deviation signal. The system determines a frequency signal that corresponds a frequency estimation of the monitored signal by applying a frequency estimation when values of the measurement signal are less than a deviation threshold and maintaining the frequency signal at a constant value when values of the measured signal equal or exceeds the deviation threshold.
    Type: Application
    Filed: March 17, 2021
    Publication date: October 21, 2021
    Inventors: Lingwei Zhan, Thomas J. King, JR., Fuhua Li, Yilu Liu, Wenxuan Yao, He Yin, Bailu Xiao
  • Publication number: 20210285995
    Abstract: A method includes performing by a processor: receiving a plurality of power system synchrophasor measurements over a time interval from a plurality of phasor measurement units (PMUs) in a power system, determining a variation in frequency of a power signal generated by the power system based on the plurality of power system synchrophasor measurements, and determining a clock time shift based on the variation in frequency of the power signal.
    Type: Application
    Filed: March 13, 2020
    Publication date: September 16, 2021
    Inventors: Yilu Liu, Ling Wu, Jingtao Ma, Thomas Bauer
  • Publication number: 20210231716
    Abstract: Respective phasor values are recursively computed from respective ones of a series of signal samples for a node of a power system such that each phasor value is computed from a previously computed phasor value. Frequency values are recursively computed from the phasor values for respective ones of the signal samples. Recursive computing of frequency values may include computing respective phase angle values from respective ones of the phasor values, recursively computing coefficient values for a polynomial that fits the phase angle values, and recursively computing the frequency values from the coefficient values. The samples may be generated at a sampling rate and the phasor values and the frequency values may be produced at a rate that is the same as the sampling rate. Embodiments may provide methods, apparatus and computer readable media that implement such operations.
    Type: Application
    Filed: January 16, 2020
    Publication date: July 29, 2021
    Inventors: Lingwei Zhan, Bailu Xiao, He Yin, Fuhua Li, Wenxuan Yao, Zhi Li, Thomas King, Yilu Liu
  • Patent number: 11069370
    Abstract: Systems and methods for detecting a tampering and identifying a location of a digital recording are provided. A frequency sequence and a phase angle sequence may be extracted from the digital recording. A portion of the frequency sequence may be matched to one of a plurality of reference frequency sequences, and a portion of the phase angle sequence may be matched to one of a plurality of reference phase angle sequences. Tampering of the digital recording may be detected when the frequency and phase sequences differ from the matched reference sequences. Moreover, a noise sequence may be extracted from the extracted frequency sequence. A location of the digital recording may be identified by matching the noise sequence to one of a plurality of noise sequences of the plurality of reference frequency sequences.
    Type: Grant
    Filed: January 11, 2016
    Date of Patent: July 20, 2021
    Assignees: UNIVERSITY OF TENNESSEE RESEARCH FOUNDATION, UT-BATTELLE, LLC
    Inventors: Jidong Chai, Yilu Liu, Jiecheng Zhao, Wenxuan Yao, Thomas J. King
  • Patent number: 10948527
    Abstract: A method includes performing by a processor: receiving a plurality of power system phase angle measurements over a time interval from a plurality of phasor measurement units (PMUs) in a power system, generating a phase angle curve over the time interval based on the plurality of power system phase angle measurements, and detecting a sustained oscillation event in a power signal generated by the power system based on an envelope of the phase angle curve.
    Type: Grant
    Filed: May 21, 2019
    Date of Patent: March 16, 2021
    Assignee: University of Tennessee Research Foundation
    Inventors: Yilu Liu, Ling Wu, Wenpeng Yu
  • Patent number: 10884042
    Abstract: A method includes performing by a processor: receiving a first plurality of power system frequency measurements from a plurality of phasor measurement units (PMUs) in the power system over a first time interval, generating a first plurality of multi-dimensional ellipsoids based on the first plurality of power system frequency measurements, extracting a plurality of first graphic parameter values from the first plurality of multi-dimensional ellipsoids, respectively, performing a regression analysis on the plurality of first graphic parameter values to generate a predictive relationship between the plurality of first graphic parameter values and inertia values of the power system, receiving a second plurality of power system frequency measurements from the plurality of PMUs over a second time interval, generating a second plurality of multi-dimensional ellipsoids based on the second plurality of power system frequency measurements, extracting a plurality of second graphic parameter values from the second plura
    Type: Grant
    Filed: June 5, 2018
    Date of Patent: January 5, 2021
    Assignee: UNIVERSITY OF TENNESSEE RESEARCH FOUNDATION
    Inventors: Yong Liu, Yi Cui, Yilu Liu
  • Publication number: 20200409324
    Abstract: An apparatus includes a photovoltaic module and a computation module that is coupled to the photovoltaic module and is configured to receive power therefrom, the computation module being configured to communicate an active message to a controller in response to the computation module transitioning to a power on state and configured to receive a task command from the controller in response to communicating the active message to the controller.
    Type: Application
    Filed: June 25, 2020
    Publication date: December 31, 2020
    Inventors: Yilu Liu, Robert Gardner, Yuru Wu
  • Publication number: 20200371143
    Abstract: A method includes performing by a processor: receiving a plurality of synchrophasor measurements of a power system signal associated with a time interval from a phasor measurement unit (PMU), each of the plurality of synchrophasor measurements including a phase angle, frequency value, and a timestamp associated with the synchrophasor measurement, determining a plurality of relative phase angles based on the plurality of phase angles, determining a correlation coefficient between the plurality of relative phase angles and a plurality of corresponding frequency values of the power system signal, and detecting an error in the plurality of timestamps based on the correlation coefficient; estimating the error in the plurality of timestamps based on the plurality of relative phase angles and the plurality of corresponding frequency values.
    Type: Application
    Filed: May 21, 2019
    Publication date: November 26, 2020
    Inventors: Yilu Liu, Wenpeng YU, Wenxuan YAO