Patents by Inventor Qizhen LI

Qizhen LI 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).

  • Generalized pulse width modulation technique for specific inter-harmonics control of the inverters
    Patent number: 11095279
    Abstract: This disclosure provides a PSR-PWM technique for high power active front-end inverters to damp a specific inter-harmonic that may cause relative sub-synchronous resonance in power system. Due to the strong interaction between wind power converters, photovoltaic converters, FACTS devices and HVDC transmission, low-frequency oscillations occur from a few Hz to dozens of Hz, or even high-frequency oscillations ranging from about 300-2000 Hz. Meanwhile, low-frequency oscillations ranging from 0.6 Hz to 7 Hz occur in the power supply systems of many electric locomotives. Even in the case of large-scale train outage, low-frequency oscillation will lead to abnormal locomotive dispatching system; in addition, the power grid voltage disturbance and flicker caused by a large number of high-power are furnaces and other nonlinear loads in the industrial field with a passband inter-harmonic frequency ranging from 0.05 Hz-90 Hz and so on are detected.
    Type: Grant
    Filed: May 6, 2020
    Date of Patent: August 17, 2021
    Assignee: WUHAN UNIVERSITY
    Inventors: Hui Zhang, Yigang He, Kaipei Liu, Yuzheng Guo, Yongguang Cheng, Jie Xie, Lei Xu, Jintao Zhou, Yuanzhe Ge, Qizhen Li
  • GENERALIZED PULSE WIDTH MODULATION TECHNIQUE FOR SPECIFIC INTER-HARMONICS CONTROL OF THE INVERTERS
    Publication number: 20200285130
    Abstract: This disclosure provides a PSR-PWM technique for high power active front-end inverters to damp a specific inter-harmonic that may cause relative sub-synchronous resonance in power system. Due to the strong interaction between wind power converters, photovoltaic converters, FACTS devices and HVDC transmission, low-frequency oscillations occur from a few Hz to dozens of Hz, or even high-frequency oscillations ranging from about 300-2000 Hz. Meanwhile, low-frequency oscillations ranging from 0.6 Hz to 7 Hz occur in the power supply systems of many electric locomotives. Even in the case of large-scale train outage, low-frequency oscillation will lead to abnormal locomotive dispatching system; in addition, the power grid voltage disturbance and flicker caused by a large number of high-power are furnaces and other nonlinear loads in the industrial field with a passband inter-harmonic frequency ranging from 0.05 Hz-90 Hz and so on are detected.
    Type: Application
    Filed: May 6, 2020
    Publication date: September 10, 2020
    Applicant: WUHAN UNIVERSITY
    Inventors: Hui ZHANG, Yigang HE, Kaipei LIU, Yuzheng GUO, Yongguang CHENG, Jie XIE, Lei XU, Jintao ZHOU, Yuanzhe GE, Qizhen LI