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Energy efficiency and cost are the two key driving factors for increased usage of hybrid- and DC-microgrids in both urban and rural settings. In order to accomplish this critical objective, number of energy conversion stages from source to load need to be reduced and efficiency of every power conversion electronic block needs to be increased by carefully taking into account system-level interactions...
In an optical wavelength division multiplexed (WDM) network, link or node failures may result in huge amounts of lost data, due to the enormous fiber throughput. This requires that optical WDM network be designed to be resilient to failures. Thus, survivability can be defined as the ability to respond gracefully to such failures. This chapter presents a comprehensive survey of various mechanisms proposed...
The field-failures of a power converter depends on the reliability characteristics of circuit components, package and interconnect parasitics, thermal management and cooling, load characteristics, and the field operating environment, among other factors. In this paper, power supply field-reliability improvement by careful screening of power MOSFET's is reported. A new power MOSFET screening criteria...
Silicon Carbide (SiC) is among the most promising semiconductor for high-voltage and high-temperature power electronics switching applications. A careful analysis of the current state-of-the-art commercial 4H-SiC power Schottky Barrier Diodes (SBDs) shows that these devices are operated well below their true avalanche breakdown potential. It is found that the breakdown voltage ratings of these devices...
Global use of solar energy and wind energy will provide clean energy for sustainable global economic growth. The use of photovoltaic systems for DC power generation and the delivery and the utilization of DC power will bring revolution in energy field by providing ultra-low-cost clean energy to rich and poor all over the world. Ultra large scale manufacturing of PV modules coupled with wide band gap...
The dv/dt switching limitations of power semiconductor devices in a boost DC-DC power converter are evaluated using circuit simulations and accurate circuit simulation models. State-of-the-art commercial silicon CoolMOS devices, commercial Silicon Carbide (SiC) power Schottky Barrier Diodes (SBD??s), and emerging Gallium Nitride (GaN) power transistors are considered. It is shown that although SiC...
Bidirectional dc-dc converters (BDCs) are used in many applications when bidirectional energy transfer between two DC buses is needed. They are used as an interface circuit between ultra-capacitor and DC bus in a Hybrid Electric Vehicle (HEV). Since the voltage levels of the ultra-capacitor and DC bus are different, the interface circuitry must be able to increase or decrease the voltage level in...
A smart wireless DC micro-grid suitable for efficient utilization of energy available from Distributed Renewable Energy Generators (DREGs) is described. This concept is experimentally demonstrated using a 40 W solar photovoltaic (PV) array delivering power to fluorescent lighting; other DC loads such as Light-Emitting Diodes (LEDs) and DC ceiling fans can be easily integrated into the proposed hybrid...
A critical evaluation of high-power electronics switching in semiconductor materials is made from the standpoint of performance, reliability, and commercial viability. This study takes into account recent experimental results obtained from the field-reliability study of silicon power MOSFETs in high-density power supplies where residual material defects present in the space charge region of the device...
Advanced circuit component, packaging, and thermal management technologies are critically evaluated for developing efficient integrated DC-DC power converters; and, important challenges and potential limitations are identified. It is shown that heterogeneous chip-scale integration of GaN power FETs, silicon CMOS control, integrated power inductors, and microchip capacitors using the new high-density,...
A new, smart distributed DC micro-grid suitable for high-penetration and that efficiently utilizes energy available from distributed, renewable generators is described. It is shown that energy saving in excess of 10% is feasible using the proposed DC power distribution system when compared to the current approach where inverters are used. This conclusion is substantiated by first-order calculations...
Performance evaluation of low-voltage silicon and GaN power FETs is presented for chip-scale DC-DC power converter applications. The circuit calculations are based on an improved circuit model for the FET with accurate description of terminal capacitances and on-resistance. It is shown that GaN power FETs combined with silicon MOS power diodes can potentially lead to nearly 82% power conversion efficiency...
Dens evaginatus (DE) and dens invaginatus (DI) are developmental anomalies that affect the shape of the teeth. Although they have been found singly and in association with other developmental anomalies in the same patient, it is uncommon to observe these two anomalies in the same tooth. There are only a few published cases of concurrent DI and DE in the same tooth. The patient in the case reported...
To achieve the highest power conversion efficiency, heterogeneous chip-scale integration of silicon-based and GaN-based power switches with SiC power diodes, silicon CMOS control IC, MEMS inductor and micro microchip supercapacitor assembled using advanced packaging and microcooling is reported.
Described within is a system for performing a minimally invasive robotic surgery. To facilitate this means, an advanced unltrasonic/inertial tracking system is used in place of the standard optical tracking systems. This technique will decrease overall radiation, both to the surgeon as well as the patient. Overall accuracy of the procedure will also be increased, thusly increasing the success rate...
Detailed performance evaluation of silicon and GaN power FETs is presented for chip-scale DC/DC converter applications. It is shown that improved GaN power FETs and silicon MOS power diodes can potentially lead to nearly 90% power conversion efficiency when switched at 5 MHz in a synchronous buck converter topology.
The design of disruptive chip-scale integration of DC/DC power converters using breakthrough silicon and GaN power semiconductor switching devices, silicon CMOS control IC, MEMS inductor and microchip supercapacitor assembled using novel “Quilt Packaging” and microcooling to achieve nearly 90% power conversion efficiency is reported.
Long-term field-reliability of gallium nitride (GaN) and silicon carbide (SiC) power switching devices is critically discussed in terms of bulk material defects. A new static reverse bias stress test circuit with a reactive load is proposed to delineate devices prone to field-failures.
Semiconductor materials and devices used for high-power switching and amplification of electrical and optical signals are often subjected to extreme levels of electrical and thermal stresses. This paper presents new opportunities for developing rugged power semiconductor devices to meet the challenges of the 21st century energy conversion applications.
We integrate fundamental principles from formal mathematics, engineering, and information sciences to develop novel distributed sensor-based networks for management of the environment and the natural ecosystem. More precisely, we are developing ENVNET - ENVironmental sensor NETwork, a cognitive wireless sensor network to proactively collect information, monitor, and control the health of our natural...
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