Now showing items 33-47 of 47

    • Optimal trajectory control for LLC resonant converter for LED PWM dimming 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Virginia Polytechnic Institute and State University; Lee, Fred C.; Ji, Shu; Feng, Weiyi (United States Patent and Trademark Office, 2016-03-01)
      Pulse width modulation is provided for controlling a resonant power converter, particularly for dimming of light emitting diode arrays without loss of efficiency. Dynamic oscillation due to the beginning of a pulse width ...
    • Optimal trajectory control for LLC resonant converter for soft start-up 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Virginia Tech Intellectual Properties, Inc.; Lee, Fred C.; Feng, Weiyi (United States Patent and Trademark Office, 2016-04-19)
      By setting switching instants of a switching circuit of a resonant power converter based on current in a resonant circuit reaching a current limit of a current limitation band, soft start-up of the power converter can be ...
    • Parallel devices having balanced switching current and power 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Virginia Tech Intellectual Properties, Inc.; Toyota Motor Engineering & Manufacturing North American, Inc.; Wang, Chi-Ming; Mao, Yincan; Miao, Zichen; Ngo, Khai D. (United States Patent and Trademark Office, 2018-10-30)
      A power circuit includes a power source for providing electrical power and two driving transistors being disposed in parallel and receiving electrical power from the power source. Each of the two driving transistors includes ...
    • Power switch drivers with equalizers for paralleled switches 

      Virginia Tech Intellectual Properties, Inc.; Miao, Zichen; Ngo, Khai D.; Zhang, Lujie (United States Patent and Trademark Office, 2018-06-12)
      Capacitors connected between gate terminals of a plurality of parallel-connected power transistors are charged and discharged in each switching cycle to provide a plurality of power transistor control waveforms from a ...
    • Power-cell switching-cycle capacitor voltage control for modular multi-level converters 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Virginia Tech Intellectual Properties, Inc.; Wang, Jun; Boroyevich, Dushan; Burgos, Rolando P.; Wen, Bo (United States Patent and Trademark Office, 2018-05-08)
      In a modular multi-level power converter, additional switching states are interleaved between main switching states that control output voltage or waveform. The additional switching states provide current from a DC-link ...
    • Semiconductor module arrangement 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Virginia Tech Intellectual Properties, Inc.; DiMarino, Christina; Boroyevich, Dushan; Burgos, Rolando P.; Johnson, Mark (United States Patent and Trademark Office, 2018-07-24)
      In a switching module structure that includes a low-impedance path to ground, such as a parasitic capacitance of an insulating substrate, a further insulating substrate presenting a parasitic capacitance placed in series ...
    • Structural Resemblance Between Droop Controllers and Phase-Locked Loops 

      Zhong, Qing-Chang; Boroyevich, Dushan (IEEE, 2016)
      It is well known that droop control is fundamental to the operation of power systems and now the parallel operation of inverters, while phase-locked loops (PLLs) are widely adopted in modern electrical engineering. In this ...
    • Superjunction Power Transistors With Interface Charges: A Case Study for GaN 

      Ma, Yunwei; Xiao, Ming; Zhang, Ruizhe; Wang, Han; Zhang, Yuhao (2019-12-13)
      Recent progress in p-GaN trench-filling epitaxy has shown promise for the demonstration of GaN superjunction (SJ) devices. However, the presence of n-type interface charges at the regrowth interfaces has been widely observed. ...
    • System and method for impedance measurement using chirp signal injection 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Virginia Tech Intellectual Properties, Inc.; Huntington Ingalls Incorporated; Boroyevich, Dushan; Mattavelli, Paolo; Belkhayat, Mohamed; Shen, Zhiyu; Jaksic, Marko D.; Verhulst, Jacob (United States Patent and Trademark Office, 2017-04-11)
      A method for impedance measurement using chirp signal injection is provided. The method includes injecting at least one chirp signal into the three-phase AC system, and collecting at least one response to the at least one ...
    • System and method for impedance measurement using series and shunt injection 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Virginia Tech Intellectual Properties, Inc.; Huntington Ingalls Incorporated; Boroyevich, Dushan; Mattavelli, Paolo; Belkhayat, Mohamed; Shen, Zhiyu; Jaksic, Marko D.; Verhulst, Jacob (United States Patent and Trademark Office, 2017-02-07)
      A method for impedance measurement in a three-phase AC system is provided. The method includes injecting a shunt perturbation signal into the three-phase AC system and collecting a response to the shunt perturbation signal, ...
    • Transient performance improvement for constant on-time power converters 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Virginia Tech Intellectual Properties, Inc.; Li, Qiang; Liu, Pei-Hsin; Lee, Fred C.; Bari, Syed (United States Patent and Trademark Office, 2018-10-23)
      Response of a variable frequency switching constant on-time or adaptive on-time controlled power converter to a large step-up or step-down change in load is improved with a simple circuit that detects magnitude and polarity ...
    • Two-stage multichannel LED driver with CLL resonant circuit 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Virginia Tech Intellectual Properties, Inc.; Li, Qiang; Lee, Fred C.; Chen, Xuebing; Huang, Daocheng (United States Patent and Trademark Office, 2017-01-10)
      In a two-stage power converter providing voltage regulation in a first stage, zero voltage switching (ZVS) is provided in switches in an unregulated, constant frequency second stage of a two-stage power converter by an ...
    • Universal system structure for low power adapters 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); 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 ...
    • V^2 power converter control with capacitor current ramp compensation 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Virginia Tech Intellectual Properties, Inc.; Liu, Pei-Hsin; Lee, Fred C.; Yan, Yingyi (United States Patent and Trademark Office, 2017-03-21)
      Operation of a switching power converter having an output capacitor having a small equivalent series resistance (ESR) is stabilized and jitter reduced by sensing capacitor current with gain and combining the resulting ...
    • Zero-current transition PWM converters 

      Electrical and Computer Engineering; Center for Power Electronics Systems (CPES); Center for Innovative Technology; Intellectual Properties | Kft; Virginia Polytechnic Institute and State University; Lee, Fred C.; Hua, Guichao C. (United States Patent and Trademark Office, 1996-01-23)
      A zero-current transition pulse-width modulated (ZCT-PWM) d.c.-d.c. converter allows minority-carrier semiconductor devices such as, for example, bipolar junction transistors (BJTs), insulated gate bipolar transistors ...