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Your search keyword '"Forsyth, Andrew J."' showing total 24 results
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24 results on '"Forsyth, Andrew J."'

1. Sustainable Wireless Services with UAV Swarms Tailored to Renewable Energy Sources

Author

Donevski, Igor, Virgili, Marco, Babu, Nithin, Nielsen, Jimmy Jessen, Forsyth, Andrew J., Papadias, Constantinos B., and Popovski, Petar

Subjects
Computer Science - Networking and Internet Architecture, Electrical Engineering and Systems Science - Signal Processing
Abstract

Unmanned Aerial Vehicle (UAV) swarms are often required in off-grid scenarios, such as disaster-struck, war-torn or rural areas, where the UAVs have no access to the power grid and instead rely on renewable energy. Considering a main battery fed from two renewable sources, wind and solar, we scale such a system based on the financial budget, environmental characteristics, and seasonal variations. Interestingly, the source of energy is correlated with the energy expenditure of the UAVs, since strong winds cause UAV hovering to become increasingly energy-hungry. The aim is to maximize the cost efficiency of coverage at a particular location, which is a combinatorial optimization problem for dimensioning of the multivariate energy generation system under non-convex criteria. We have devised a customized algorithm by lowering the processing complexity and reducing the solution space through sampling. Evaluation is done with condensed real-world data on wind, solar energy, and traffic load per unit area, driven by vendor-provided prices. The implementation was tested in four locations, with varying wind or solar intensity. The best results were achieved in locations with mild wind presence and strong solar irradiation, while locations with strong winds and low solar intensity require higher Capital Expenditure (CAPEX) allocation., Comment: To be published in Transactions on Smart Grid

Published
2022

14. All-GaN-integrated cascode heterojunction field effect transistors

Author

Jiang, Sheng, Lee, Kean Boon, Guiney, Ivor, Miaja, Pablo F., Zaidi, Zaffar H., Qian, Hongtu, Wallis, David J., Forsyth, Andrew J., Humphreys, Colin J., and Houston, Peter A.

Abstract

All-GaN-integrated cascode heterojunction field effect transistors were designed and fabricated for power switching applications. A threshold voltage of +2 V was achieved using a fluorine treatment and a metal-insulator-semiconductor gate structure on the enhancement mode part. The cascode device exhibited an output current of 300 mA/mm by matching the current drivability of both enhancement and depletion mode parts. The optimization was achieved by shifting the threshold voltage of the depletion mode section to a more negative value with the addition of a dielectric layer under the gate. The switching performance of the cascode was compared to the equivalent GaN enhancement-mode-only device by measuring the hard switching speed at 200 V under an inductive load in a double pulse tester. For the first time, we demonstrate the switching speed advantage of the cascode over equivalent GaN enhancement-mode-only devices, due to the reduced Miller-effect and the unique switching mechanisms. These observations suggest that practical power switches at high power and high switching frequency will benefit as part of an integrated cascode configuration.

Published
2017

21. A Design Optimization Tool for Maximizing the Power Density of 3-Phase DC?AC Converters Using Silicon Carbide (SiC) Devices.

Author

Laird, Ian, Yuan, Xibo, Scoltock, James, and Forsyth, Andrew J.

Subjects
POWER density, SILICON carbide, DC-AC converters, PROCESS optimization, POWER tools, PASSIVE components, ELECTROMAGNETIC interference
Abstract

The emergence of wide-bandgap devices, e.g., silicon carbide (SiC), has the potential to enable very high-density power converter design with high-switching frequency operation capability. A comprehensive design tool with a holistic design approach is critical to maximize the overall system power density, e.g, by identifying the optimal switching frequency. This paper presents a system level design tool that optimizes the power density (volume or mass) of a three-phase, two-level dc–ac converter. The design tool optimizes the selection of the devices, heatsink and passive components (including the design of the line, electromagnetic interference (EMI), and dc-link filters) to maximize the power density. The structure of the optimization algorithm has been organized to reduce the number of potential design combinations by over 99%, and thus, produces fast simulation times. The design tool predicts that when SiC devices are used instead of Si ones, the power density is increased by 159.4%. A 5 kW, 600-V dc-link, three-phase, two-level dc–ac converter was experimentally evaluated in order to confirm the accuracy of the design tool. [ABSTRACT FROM PUBLISHER]

Published
2018
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24. Enhanced Average-Value Modeling of Interleaved DC?DC Converters Using Sampler Decomposition.

Author

Villarruel-Parra, Alejandro and Forsyth, Andrew J.

Subjects
*CONVERTERS (Electronics), *PREDICTION models, *TRANSFER functions, *NUCLEAR counters, *SWITCHING circuits
Abstract

To provide a basis for controller design in interleaved dc–dc converters, an improved small-signal averaged model is presented. Sampler decomposition techniques are used to represent the interleaved operation of the individual control loops within the converter. The resultant model reveals interaction effects and instability phenomena that are not predicted by a simple noninterleaved model, and which impose significant restrictions on the selection of control parameters. The model is validated by detailed simulations and experimental results from a digitally controlled dual-interleaved boost converter. [ABSTRACT FROM AUTHOR]

Published
2017
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