Now showing items 1-10 of 10

    • Accelerated commutation for passive clamp isolated boost converters 

      Virginia Tech Intellectual Properties, Inc.; Lee, Fred C.; Lai, Jih-Sheng; Zhu, Lizhi (United States Patent and Trademark Office, 2005-04-05)
      An efficient and cost effective bidirectional DC/DC converter reduces switch voltage stress via accelerated commutation allowing use of a low-cost passive clamp circuit in boost mode. The converter includes a primary ...
    • Avoiding internal switching loss in soft switching cascode structure device 

      Virginia Tech Intellectual Properties, Inc.; Li, Qiang; Lee, Fred C.; Huang, Xiucheng; Du, Weijing (United States Patent and Trademark Office, 2017-08-15)
      In a cascode switching device, avalanche breakdown of a control transistor and loss of soft switching or zero voltage switching in a high voltage normally-on depletion mode transistor having a negative switching threshold ...
    • Hybrid switch for resonant power converters 

      Virginia Tech Intellectual Properties, Inc.; Lai, Jih-Sheng; Yu, Wensong (United States Patent and Trademark Office, 2014-09-09)
      A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction ...
    • Multi-element resonant converters 

      Virginia Tech Intellectual Properties, Inc.; Lee, Fred C.; Xu, Ming Gang; Liu, Ya; Fu, Dianbo (United States Patent and Trademark Office, 2010-06-22)
      A resonant switched power converter having switching frequency controlled in response to an output voltage thereof achieves over-current protection such as at start-up or under short circuit conditions using a resonant ...
    • Multi-step simplified optimal trajectory control (SOTC) based on only Vo and I load 

      Virginia Tech Intellectual Properties, Inc.; Li, Qiang; Lee, Fred C.; Fei, Chao; Feng, Weiyi (United States Patent and Trademark Office, 2018-09-11)
      A resonant power converter is disclosed with a driving circuit generating a switching signal connecting power to a resonant tank circuit, with a voltage monitoring circuit measuring a voltage output and a load current. A ...
    • Pulse width modulated resonant power conversion 

      Virginia Tech Intellectual Properties, Inc.; Cao, Xiao Hong; The Ngo, Khai Doan; Wang, Yin (United States Patent and Trademark Office, 2014-08-19)
      A power converter including a resonant circuit is controlled by pulse width modulation (PWM) of a switching circuit to control current in the resonant circuit near the frequency of the resonant circuit (a null-immittance ...
    • Start-up circuit and control for high power isolated boost DC/DC converters 

      Virginia Tech Intellectual Properties, Inc.; Lee, Fred C.; Zhu, Lizhi; Lai, Jin-Sheng (United States Patent and Trademark Office, 2003-07-01)
      The invention is a scheme for high power isolated full-bridge boost DC/DC converters to minimize the effect of in-rush current during start-up. A single pulse width modulation controller (PWM) is possible for the present ...
    • Three-level active neutral point clamped zero voltage switching converter 

      Virginia Tech Intellectual Properties, Inc.; Boroyevich, Dushan; Li, Jin; Liu, Jinjun (United States Patent and Trademark Office, 2015-01-06)
      A main circuit of a three-level active neutral point clamped voltage source converter having a pair of additional main switches provides two paths between an output node and a neutral point in which one of the paths involves ...
    • Universal system structure for low power adapters 

      Virginia Tech Intellectual Properties, Inc.; Li, Qiang; Lee, Fred C.; Huang, Xiucheng (United States Patent and Trademark Office, 2017-12-19)
      A two-stage power converter architecture including an isolation transformer and rectification of the isolation transformer output by an LLC resonant circuit and methodology for operating the same feeds an output voltage ...
    • Zero voltage zero current three level DC-DC converter 

      Virginia Tech Intellectual Properties, Inc.; Lee, Fred C.; Canales-Abarca, Francisco; Barbosa, Peter M. (United States Patent and Trademark Office, 2002-02-19)
      A three-level DC-to-DC converter is provided having zero-voltage and zero-current switching (ZVZCS). A flying capacitor is provided on the primary side of the converter to achieve zero voltage switching (ZVS). In addition, ...