Open Access. Powered by Scholars. Published by Universities.®
Electrical and Computer Engineering Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 9 of 9
Full-Text Articles in Electrical and Computer Engineering
Simulation Of Gate Lag And Current Collapse In Gallium Nitride Field-Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, M. S. Shur, M. Asif Khan, Grigory Simin
Simulation Of Gate Lag And Current Collapse In Gallium Nitride Field-Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, M. S. Shur, M. Asif Khan, Grigory Simin
Faculty Publications
Results of two-dimensional numerical simulations of gate lag and current collapse in GaN heterostructurefield-effect transistors are presented. Simulation results clearly show that current collapse takes place only if an enhanced trapping occurs under the gate edges. Hot electrons play an instrumental role in the collapse mechanism. The simulation results also link the current collapse with electrons spreading into the buffer layer and confirm that a better electron localization (as in a double heterostructurefield-effect transistor) can dramatically reduce current collapse.
Synergetic Control Of Power Converters For Pulse Current Charging Of Advanced Batteries From A Fuel Cell Power Source, Zhenhua Jiang, Roger A. Dougal
Synergetic Control Of Power Converters For Pulse Current Charging Of Advanced Batteries From A Fuel Cell Power Source, Zhenhua Jiang, Roger A. Dougal
Faculty Publications
This paper presents a synergetic controller for pulse current charging of advanced batteries from a fuel cell power source. Pulse current charging protocol that has been shown to have many advantages over the traditional constant current/constant voltage protocol is applied in a fuel cell powered battery-charging station to reduce the total charging time. Strong nonlinearity and dynamics exist in such systems. In this paper, the synergetic control approach is applied to regulate the buck converters that control the pulse charging currents to the many batteries. A practical synergetic controller to coordinate pulse current charging of the battery is synthesized and …
Response To Comments On “Passivity-Based Control Of Saturated Induction Motors”, Levent U. Gökdere, Marwan A. Simaan, Charles W. Brice
Response To Comments On “Passivity-Based Control Of Saturated Induction Motors”, Levent U. Gökdere, Marwan A. Simaan, Charles W. Brice
Faculty Publications
Contrary to the claims made in the comments to our paper, the passivity-based controller developed for induction motors has already been tested on the same demanding trajectories used for the input–output linearization controller. The experimental results show that the passivitybased controller provides closer tracking of the same mechanical trajectory, when compared with the input–output linearization controller.
Simulation Of Hot Electron And Quantum Effects In Algan/Gan Heterostructure Field Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, H. Xu, M. S. Shur, M. Asif Khan, Grigory Simin, J. Yang
Simulation Of Hot Electron And Quantum Effects In Algan/Gan Heterostructure Field Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, H. Xu, M. S. Shur, M. Asif Khan, Grigory Simin, J. Yang
Faculty Publications
We report on simulations of electrical characteristics of AlGaN/(InGaN)/GaN heterostructurefield effect transistors with quantum and hot electroneffects taken into account. Polarization charges lead to quantum confinement of electrons in the channel and to the formation of two-dimensional electron gas. The electron quantization leads to the spread of the electronwave function into the barrier and bulk but does not have significant impact on dc electrical characteristics.Hot electrons play an important part in the charge transport by spilling over into the bulk GaN where they are captured by traps. This leads to negative differential conductivity, which is also observed experimentally. The simulation …
Control Strategies For Active Power Sharing In A Fuel-Cell-Powered Battery-Charging Station, Zhenhua Jiang, Roger A. Dougal
Control Strategies For Active Power Sharing In A Fuel-Cell-Powered Battery-Charging Station, Zhenhua Jiang, Roger A. Dougal
Faculty Publications
This paper presents an effective system design for a fuel-cell-powered battery-charging station and three control strategies for active power sharing among the batteries. This battery-charging station allows multiple batteries to be simultaneously charged. Three control strategies were investigated to coordinate the active power distribution among the battery-charging branches. The baseline control strategy Was equal rate charging. Two advanced control strategies, proportional rate charging and pulse current charging, were compared to the baseline strategy. These control strategies were realized in MaTLaB/Simulink, and the current and voltage regulations were implemented using the classical proportional-integral control approach. The system simulation was conducted in …
Symbolically Aided Model Development For An Induction Machine In Virtual Test Bed, Wenzhong Gao, Eugene V. Slovodnik, Roger A. Dougal
Symbolically Aided Model Development For An Induction Machine In Virtual Test Bed, Wenzhong Gao, Eugene V. Slovodnik, Roger A. Dougal
Faculty Publications
A new phase-domain induction machine model for use in power system dynamic simulation is developed with the aid of a symbolic tool. The symbolic tool can automatically construct a time-domain power system component model in the resistive companion form (RCF) that is widely used in time-domain simulators. The automatic differentiation technique (aDT) is utilized within the context of a symbolic modeling language, and the tool has been implemented for the virtual test bed (VTB) simulation environment. The new induction machine model was used to study start-up transients of an induction motor. The new model was verified by comparing the simulation …
Wide-Band/Dual-Band Packaged Antenna For 5-6 Ghz Wlan Application, Mohammod Ali, Tuangsit Sittironnarit, Huan-Sheng Hwang, Robert A. Sadler, Gerard James Hayes
Wide-Band/Dual-Band Packaged Antenna For 5-6 Ghz Wlan Application, Mohammod Ali, Tuangsit Sittironnarit, Huan-Sheng Hwang, Robert A. Sadler, Gerard James Hayes
Faculty Publications
A wide-band/dual-band packaged antenna is proposed for wireless local-area network (WLAN) applications in the 5.15-5.35 GHz and 5.725-5.825 GHz frequency range. The antenna is internal to the housing of a personal digital assistant, such as a Palm organizer, and has the dimensions of 28 by 9 by 3 ram on an FR4 substrate. The antenna meets or exceeds the bandwidth requirements for the dual-band IEEE 802.11a WLAN applications (5.15-5.35 GHz and 5.725-5.825 GHz) within 2:1 voltage standing-wave ratio.
Design And Analysis Of An R-Shaped Dual-Band Planar Inverted-F Antenna For Vehicular Applications, Mohammod Ali, Guangli Yang, Huan-Sheng Hwang, Tuangsit Sittironnarit
Design And Analysis Of An R-Shaped Dual-Band Planar Inverted-F Antenna For Vehicular Applications, Mohammod Ali, Guangli Yang, Huan-Sheng Hwang, Tuangsit Sittironnarit
Faculty Publications
A dual-band R-shaped planar inverted-F antenna is proposed for vehicular application. Utilization of this unique geometry dual-frequency operation is achieved with a single feed. The proposed antenna operates in the 225- and 450-MHz bands. Input impedance and return loss data as function of various antenna parameters are presented, which show that parameters can be adjusted in order to obtain optimum tuning. Radiation pattern data for the antenna mounted on the roof of two types of vehicles are given. The pattern in the low-frequency band is essentially omnidirectional while that in the high-frequency band is directional and normal to the antenna …
Exploration Of Artificial Multiferroic Thin-Film Heterostructures Using Composition Spreads, K.-S. Chang, M. A. Aronova, C.-L. Lin, M. Murakami, M.-H. Yu, Jason R. Hattrick-Simpers, O. O. Famodu, S. Y. Lee, R. Ramesh, M. Wuttig, I. Takeuchi, C. Gao, L. A. Bendersky
Exploration Of Artificial Multiferroic Thin-Film Heterostructures Using Composition Spreads, K.-S. Chang, M. A. Aronova, C.-L. Lin, M. Murakami, M.-H. Yu, Jason R. Hattrick-Simpers, O. O. Famodu, S. Y. Lee, R. Ramesh, M. Wuttig, I. Takeuchi, C. Gao, L. A. Bendersky
Faculty Publications
We have fabricated a series of composition spreads consisting of ferroelectric BaTiO3 and piezomagnetic CoFe2O4 layers of varying thicknesses modulated at nanometer level in order to explore artificial magnetoelectricthin-film heterostructures. Scanning microwavemicroscopy and scanning superconducting quantum interference device microscopy were used to map the dielectric and magnetic properties as a function of continuously changing average composition across the spreads, respectively. Compositions in the middle of the spreads were found to exhibit ferromagnetism while displaying a dielectric constant as high as ≈120.