Patents by Inventor Julie Haihui Lu

Julie Haihui Lu 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).

  • Direct current bus voltage control
    Patent number: 11631975
    Abstract: For Direct Current (DC) bus voltage control, a method generates a q-axis reference current from a DC voltage error that includes a DC voltage input modified by a DC bus voltage in a closed outer loop. The method further generates a d-axis reference current from the DC voltage error, wherein the second-order harmonic in the d-axis reference current is delayed from that in q-axis reference current by 90 degrees. The method generates a q-axis current from the q-axis reference current. The method generates a d-axis current from the d-axis reference current. The second-order harmonic in d-axis current is offset from the second-order harmonic in q-axis current by 90 degrees. The method controls the DC bus voltage of a voltage control plant to mitigate a second-order harmonic in the DC bus voltage with the second-order harmonics in the q-axis current and the d-axis current.
    Type: Grant
    Filed: March 5, 2021
    Date of Patent: April 18, 2023
    Assignee: Rockwell Automation Technologies, Inc.
    Inventors: Lei Jin, Julie Haihui Lu, Ahmed Mohamed Sayed Ahmed
  • DIRECT CURRENT BUS VOLTAGE CONTROL
    Publication number: 20220285935
    Abstract: For Direct Current (DC) bus voltage control, a method generates a q-axis reference current from a DC voltage error that includes a DC voltage input modified by a DC bus voltage in a closed outer loop. The method further generates a d-axis reference current from the DC voltage error, wherein the second-order harmonic in the d-axis reference current is delayed from that in q-axis reference current by 90 degrees. The method generates a q-axis current from the q-axis reference current. The method generates a d-axis current from the d-axis reference current. The second-order harmonic in d-axis current is offset from the second-order harmonic in q-axis current by 90 degrees. The method controls the DC bus voltage of a voltage control plant to mitigate a second-order harmonic in the DC bus voltage with the second-order harmonics in the q-axis current and the d-axis current.
    Type: Application
    Filed: March 5, 2021
    Publication date: September 8, 2022
    Inventors: Lei Jin, Julie Haihui Lu, Ahmed Mohamed Sayed Ahmed