The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
David J. Perreault - One of the best experts on this subject based on the ideXlab platform.
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Diode Evaluation and Series Diode Balancing for High-Voltage High-Frequency Power Converters
IEEE Transactions on Power Electronics, 2020Co-Authors: David J. PerreaultAbstract:Miniaturization of high-voltage power converters is severely limited by the availability of fast switching, low-loss high-voltage Diodes. This article explores techniques for using discrete low-voltage Diodes in series as one high-voltage Diode in high-frequency applications (e.g., hundreds of kHz and above). We identify that when series connecting Diodes, the parasitic capacitance from the physical Diode interconnections to common can result in voltage and temperature imbalance among the Diodes, along with increased loss. We quantify the imbalance and propose two related compensation techniques. To validate the approaches, a full-bridge rectifier is tested with each branch consisting of four 3.3 kV SiC Diodes in series. Experimental results showcase the imbalance and demonstrate the effectiveness of the compensation techniques. Additionally, we characterize the performance of a range of Diodes for use in high-frequency, high-voltage converters. The proposed technique and evaluation results will be valuable for the design of lightweight and miniaturized high-voltage power converters.
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Series Diode balancing and Diode evaluation for high-voltage high-frequency power converters
2019 IEEE Applied Power Electronics Conference and Exposition (APEC), 2019Co-Authors: David J. PerreaultAbstract:Miniaturization of high voltage power converters is severely limited by the availability of fast-switching, low-loss high-voltage Diodes. This paper explores techniques for using discrete low-voltage Diodes in series as one high voltage Diode. We identify that when series connecting Diodes, the parasitic capacitance from the physical Diode interconnections to common can result in voltage and temperature imbalance among the Diodes, along with increased loss. We quantify the imbalance and propose two related compensation techniques. To validate the approaches, a full-bridge rectifier is tested with each branch consisting of four 3.3 kV SiC Diodes in series. Experimental results showcase the imbalance and demonstrate the effectiveness of the compensation techniques. Additionally, we characterize the performance of a range of Diodes for use in high-frequency, high-voltage converters. The proposed technique and evaluation results will be valuable for the design of lightweight and miniaturized high voltage power converters.
S. Burger - One of the best experts on this subject based on the ideXlab platform.
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Quaternary InGaAsSb Thermophotovoltaic Diodes
IEEE Transactions on Electron Devices, 2006Co-Authors: M. W. Dashiell, J Beausang, H. Ehsani, G. Nichols, D. M. Depoy, L. R. Danielson, P. Talamo, K. D. Rahner, E. Brown, S. BurgerAbstract:InxGa1-xAsySb1-y thermophotovoltaic (TPV) Diodes were grown lattice matched to GaSb substrates by metal-organic vapor phase epitaxy in the bandgap range of EG = 0.5 to 0.6 eV. InGaAsSb TPV Diodes, utilizing front-surface spectral control filters, are measured with thermal-to-electric conversion efficiency and power density (PD) of nTPV = 19.7% and PD = 0.58 W/cm2, respectively, for a radiator temperature of Tradiator = 950 degC, Diode temperature of TDiode = 27 degC, and Diode bandgap of EG = 0.53 eV. Practical limits to TPV energy conversion efficiency are established using measured recombination coefficients and optical properties of front surface spectral control filters which for 0.53-eV InGaAsSb TPV energy conversion are nTPV = 28% and PD = 0.85 W/cm2 at the above operating temperatures. The most severe performance limits are imposed by 1) Diode open-circuit voltage (VOC) limits due to intrinsic Auger recombination and 2) parasitic photon absorption in the inactive regions of the module. Experimentally, the Diode VOC is 15% below the practical limit imposed by intrinsic Auger recombination processes. Analysis of InGaAsSb Diode electrical performance versus Diode architecture indicates that VOC and thus efficiency are limited by extrinsic recombination processes such as through bulk defects
Michelle A. Moram - One of the best experts on this subject based on the ideXlab platform.
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Light-emitting Diodes and their applications in energy-saving lighting
Proceedings of the Institution of Civil Engineers - Energy, 2011Co-Authors: Michelle A. MoramAbstract:New light-emitting Diode technology offers significant promise for reducing energy usage in lighting and display applications. This paper introduces light-emitting Diodes, sets their performance in context and predicts how an ultimate reduction of up to 15% of our total electricity consumption could be achieved if light-emitting Diodes were to replace existing forms of household, commercial and street lighting. This would be achieved not only through the increased luminous efficacy of light-emitting Diode light sources, but also by increasing the power factor of the entire lighting unit and by introducing control systems that take advantage of the long-lasting, fully dimmable nature of light-emitting Diodes. However, the high cost of light-emitting-Diode-based lighting is the main barrier to widespread consumer uptake. Consequently, this paper outlines routes towards improved performance and lower costs, both for light-emitting Diodes and the units they are built into. Because light-emitting Diode lightin...
Robert Kaplar - One of the best experts on this subject based on the ideXlab platform.
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Ultrafast Reverse Recovery Time Measurement for Wide-Bandgap Diodes
IEEE Transactions on Power Electronics, 2017Co-Authors: Daniel Mauch, Fred J. Zutavern, J. Delhotal, M. P. King, Jason C. Neely, I. C. Kizilyalli, Robert KaplarAbstract:A system is presented that is capable of measuring subnanosecond reverse recovery times of Diodes in wide-bandgap materials over a wide range of forward biases (0 – 1 A) and reverse voltages (0 – 10 kV). The system utilizes the step recovery technique and comprises a cable pulser based on a silicon (Si) Photoconductive Semiconductor Switch (PCSS) triggered with an Ultrashort Pulse Laser, a pulse charging circuit, a Diode biasing circuit, and resistive and capacitive voltage monitors. The PCSS-based cable pulser transmits a 130 ps rise time pulse down a transmission line to a capacitively coupled Diode, which acts as the terminating element of the transmission line. The temporal nature of the pulse reflected by the Diode provides the reverse recovery characteristics of the Diode, measured with a high bandwidth capacitive probe integrated into the cable pulser. This system was used to measure the reverse recovery times (including the creation and charging of the depletion region) for two Avogy gallium nitride Diodes; the initial reverse recovery time was found to be 4 ns and varied minimally over reverse biases of 50–100 V and forward current of 1–100 mA.
M. W. Dashiell - One of the best experts on this subject based on the ideXlab platform.
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Quaternary InGaAsSb Thermophotovoltaic Diodes
IEEE Transactions on Electron Devices, 2006Co-Authors: M. W. Dashiell, J Beausang, H. Ehsani, G. Nichols, D. M. Depoy, L. R. Danielson, P. Talamo, K. D. Rahner, E. Brown, S. BurgerAbstract:InxGa1-xAsySb1-y thermophotovoltaic (TPV) Diodes were grown lattice matched to GaSb substrates by metal-organic vapor phase epitaxy in the bandgap range of EG = 0.5 to 0.6 eV. InGaAsSb TPV Diodes, utilizing front-surface spectral control filters, are measured with thermal-to-electric conversion efficiency and power density (PD) of nTPV = 19.7% and PD = 0.58 W/cm2, respectively, for a radiator temperature of Tradiator = 950 degC, Diode temperature of TDiode = 27 degC, and Diode bandgap of EG = 0.53 eV. Practical limits to TPV energy conversion efficiency are established using measured recombination coefficients and optical properties of front surface spectral control filters which for 0.53-eV InGaAsSb TPV energy conversion are nTPV = 28% and PD = 0.85 W/cm2 at the above operating temperatures. The most severe performance limits are imposed by 1) Diode open-circuit voltage (VOC) limits due to intrinsic Auger recombination and 2) parasitic photon absorption in the inactive regions of the module. Experimentally, the Diode VOC is 15% below the practical limit imposed by intrinsic Auger recombination processes. Analysis of InGaAsSb Diode electrical performance versus Diode architecture indicates that VOC and thus efficiency are limited by extrinsic recombination processes such as through bulk defects
