Now showing items 1-20 of 32

    • Zero-current transition PWM converters 

      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 ...
    • A diffusion-viscous analysis and experimental verification of defect formation in sintered silver bond-line 

      Xiao, K.; Ngo, K. D. T.; Lu, G. Q. (Cambridge University Press, 2014-04-01)
      The low-temperature joining technique (LTJT) by silver sintering is being implemented by major manufacturers of power electronic devices and modules for bonding power semiconductor chips. A common die-attach material used ...
    • 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 ...
    • Optimal trajectory control for LLC resonant converter for LED PWM dimming 

      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 

      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 ...
    • Iaverage current mode (ACM) control for switching power converters 

      Virginia Tech Intellectual Properties, Inc.; Lee, Fred C.; Mattavelli, Paolo; Yan, Yingyi (United States Patent and Trademark Office, 2016-05-17)
      Providing a fast current sensor direct feedback path to a modulator for controlling switching of a switched power converter in addition to an integrating feedback path which monitors average current for control of a modulator ...
    • Method and apparatus for driving a power device 

      Virginia Tech Intellectual Properties, Inc.; Toyota Motor Engineering & Manufacturing North American, Inc.; Wang, Chi-Ming; Shin, Jongwon; Ngo, Khai D. (United States Patent and Trademark Office, 2016-12-27)
      Aspects of the disclosure provide a circuit for driving a power switch. The circuit includes a first circuit configured to provide a charging current to charge a control terminal of the power switch, a second circuit ...
    • Two-stage multichannel LED driver with CLL resonant circuit 

      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 ...
    • System and method for impedance measurement using series and shunt injection 

      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, ...
    • High frequency integrated point-of-load power converter with embedded inductor substrate 

      Virginia Tech Intellectual Properties, Inc.; Li, Qiang; Lee, Fred C.; Su, Yipeng; Zhang, Wenli (United States Patent and Trademark Office, 2017-02-07)
      A low profile power converter structure is provide wherein volume is reduced and power density is increased to approach 1 KW/in3 by at least one of forming an inductor as a body of magnetic material embedded in a substrate ...
    • Method and apparatus for current/power balancing 

      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, 2017-02-28)
      Aspects of the disclosure provide a power circuit that includes a first switch circuit in parallel with a second switch circuit. The first switch circuit and the second switch circuit are coupled to a first driving node, ...
    • Method for reducing or eliminating conducted common mode noise in a transformer 

      Virginia Tech Intellectual Properties, Inc.; Li, Qiang; Lee, Fred C.; Huang, Daocheng; Yang, Yuchen (United States Patent and Trademark Office, 2017-03-07)
      At least one shield member interposed between primary and secondary windings of a transformer and connected to the primary and/or secondary windings forms a distributed parasitic capacitance between the shield member and ...
    • V^2 power converter control with capacitor current ramp compensation 

      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 ...
    • System and method for impedance measurement using chirp signal injection 

      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 ...
    • Anti-islanding detection for three-phase distributed generation 

      Virginia Tech Intellectual Properties, Inc.; Dong, Dong; Boroyevich, Dushan; Mattavelli, Paolo (United States Patent and Trademark Office, 2017-04-25)
      Wobbling the operating frequency of a phase-locked loop (PLL), preferably by adding a periodic variation is feedback gain or delay in reference signal phase allows the avoidance of any non-detection zone that might occur ...
    • Method and apparatus to improve power device reliability 

      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, 2017-05-23)
      Aspects of the disclosure provide a power device that includes an upper power module and a lower power module. The upper power module and the lower power module are coupled in series between two supply voltages, and are ...
    • External ramp autotuning for current mode control of switching converter 

      Virginia Tech Intellectual Properties, Inc.; Liu, Pei-Hsin; Lee, Fred C.; Mattavelli, Paolo; Yan, Yingyi (United States Patent and Trademark Office, 2017-06-13)
      Peak current, valley current or average current mode controlled power converters in either digital or analog implementations obtain a stabilized feedback loop and allow high system bandwidth design by use of an external ...
    • Maximum power point tracking for solar panels 

      Virginia Tech Intellectual Properties, Inc.; Lee, Fred C.; Wang, Feng; Wu, Xinke; Wang, Zijian (United States Patent and Trademark Office, 2017-06-20)
      Approximately one-half of the loss of delivered power from a solar panel having photovoltaic (PV) cells connected in series to form sub-panels due to shading is recovered at low hardware cost by connecting sub-panels in ...
    • 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 ...
    • Correlation between tunability and anisotropy in magnetoelectric voltage tunable inductor (VTI) 

      Yan, Yongke; Geng, Liwei D.; Zhang, Lujie; Gao, Xiangyu; Gollapudi, Sreenivasulu; Song, Hyun-Cheol; Dong, Shuxiang; Sanghadasa, Mohan; Khai Ngo; Wang, Yu U.; Priya, Shashank (Springer Nature, 2017-11-22)
      Electric field modulation of magnetic properties via magnetoelectric coupling in composite materials is of fundamental and technological importance for realizing tunable energy efficient electronics. Here we provide ...