Engineering Commons^™

Modeling And Test Of The Efficiency Of Electronic Speed Controllers For Brushless Dc Motors, Clayton R. Green

Master's Theses

Small electric uninhabited aerial vehicles (UAV) represent a rapidly expanding market requiring optimization in both efficiency and weight; efficiency is critical during cruise or loiter where the vehicle operates at part power for up to 99% of the mission time. Of the four components (battery, motor, propeller, and electronic speed controller (ESC)) of the electric propulsion system used in small UAVs, the ESC has no accepted performance model and almost no published performance data. To collect performance data, instrumentation was developed to measure electrical power in and out of the ESC using the two wattmeter method and current sense resistors; …

Design And Comparison Of Si-Based And Sic-Based Three-Phase Pv Inverters, Wei Fu

Theses and Dissertations

The opportunities for both power density and efficiency improvements of photovoltaic (PV) inverter have come with the development of commercially available wide bandgap (WBG) devices such as Gallium Nitride (GaN), and Silicon Carbide (SiC).

In this thesis, how the replacement of Silicon (Si) Insulated Gate Bipolar Transistor (IGBT), with SiC Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) affects the power density and efficiency of a solar inverter implementation is presented. The focus is on achieving a minimum volume of the output filter which meet the current harmonic performance of IEEE standard, while meeting the thermal constraint of the semiconductor device. Efficiency improvements …

General Properties For Determining Power Loss And Efficiency Of Passive Multi-Port Microwave Networks, Ramakrishna Janaswamy

Ramakrishna Janaswamy

Starting from the scattering matrix formulation, three useful properties are derived that characterize the dissipative loss and the corresponding efficiency of a multiport, passive microwave network. Elementary examples are considered that involve both reciprocal and non-reciprocal networks to demonstrate the utility of the expressions provided. When applied to the equal-split, matched, 3-port resistive divider, they recover the known fact that the device is 50% efficient. The relations yield the new result that the efficiency of a 3-port Wilkinson power divider is 2/3 on the average. Using the results presented it is further shown that the Wilkinson power divider belongs to …

Increasing Efficiency Of Thermal Desalination, Jarrod A. Edwards, Mackinzie Washington, Chan Jung, Ben Garrison

Chancellor’s Honors Program Projects

No abstract provided.

A Study Of The Impact Of Various Geometric Factors On The Capacity Of Short Range Indoor Mimo Communications Channels, Anthony Grennan

Doctoral

MIMO antenna array systems have been proposed as a means of increasing the spectral efficiency of wireless systems. However, their performance is likely to be sub-optimal if typical uniform antenna array structures are arbitrarily positioned; as they depend on spatial multiplexing. This is particularly true for indoor environments in which transmission ranges are short resulting in a strong correlation of the main propagation paths, especially the line-of-sight components. This makes it difficult to achieve successful spatial multiplexing which depends on a decorrelated set of signal components. Thus, the physical propagation channel and geometry of the antenna arrays, especially the inter-element …