In the year 2007, the worldwide energy consumption accumulated to a total of 16.5 billion MWh. While the resources of conventional energy production cause environmental damage, renewable energy sources like solar or wind power offer a solution to substitute for coal or nuclear generated power. Countries like Denmark and Spain...
With energy prices rising and increasing concern about the influence of fossil fuels on climate change, wave energy systems are on the verge of commercial implementation. These first generation wave energy converters utilize either pneumatics or hydraulics to convert the mechanical energy of waves into electricity. For the last several...
The world’s energy consumption is growing at an alarming rate and the need for renewable energy is apparent now more than ever. Estimates have shown that optimization of the extraction of energy from the ocean could significantly aid the world’s quest for sustainable and affordable energy services for all. From...
The integration of renewable energy sources and the associated power electronics to notebook power and thermal management systems was investigated in this work. Both thermoelectric (TE) and photovoltaic (PV) energy extraction techniques were explored with the goal of achieving best sustainability. Semi-realistic usage assumptions were taken into account to evaluate...
Wave energy conversion devices are a rapidly growing interest worldwide for the potential to harness a sustainable and renewable energy source. Due to the oscillatory nature of ocean waves, the power generated from a permanent magnet linear generator (PMLG) for ocean wave energy conversion is pulsed. Focusing on direct drive...
In advanced hybrid electric vehicle development, performance and dependability are essential considerations in the design process. High efficiency is crucial in a successful design and fault tolerance is necessary to provide limp-home capability under faulted operating conditions. The reduction of electromagnetic interference is mandatory to reduce interference in communications and...
Accurate scaled modeling and simulation are critical to advancing ocean wave linear generator buoys. A 100th scaled model of ocean wave generator buoy systems is analyzed by solving the Navier-Stokes equations. These equations are numerically solved using Computational Fluid Dynamics (CFD) by implementing the front capturing method. In this thesis,...
Wind energy is a cornerstone to the world of renewables. It is widely used in many parts of the world as a clean and effective form of power generation. However, wind power has a number of drawbacks, which limits its use in many regions. Solar power has been used not...
Traditionally linear actuator applications are addressed by the use of hydraulic systems. The high maintenance cost and poor reliability will always be the most critical problem in the real applications. Benefited from both the high mechanical advantage of the roll screw and the simple structure of the switched reluctance motor,...
Commonly proposed ocean wave energy converters (OWEC) use inefficient and maintenance demanding intermediate hydraulic and pneumatic systems. We propose a novel rotary direct-drive OWEC that eliminates these intermediate stages. The new device employs a contactless force transmission system (CFTS) comprising a “piston” and a “cylinder” and a ball screw to...
The detection of motor faults at their incipient stage is of prime importance to any industrial plant. The introduction of adjustable speed drives has improved the control and the efficiency of induction motors, however, this has changed the nature of motor faults and how they can be detected.
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As more advanced hybrid electric vehicles begin emerging onto the commercial market, design algorithms for their control become increasingly more complicated. One major hurdle for designers is the mitigation and control of the created high frequency harmonics caused from switching the dc voltage into an ac voltage by use of...
Preventative motor fault detection is of prime importance for modern plant management. During research into rotor faults, performed at the Motor Systems Resource Facility (MSRF), an optimized rotor fault detection and classification method was proposed. In critical process applications, the suggested method would provide the foundation for continually monitoring a...
A significantly untapped renewable energy source exists in the world's oceans. It is estimated that if 0.2% of the ocean's untapped energy could be harnessed, it could provide power sufficient for the entire world. Ocean energy extraction is an old concept, and it is currently seeing the benefit of advancing...
Hybrid electric vehicles (HEV’s) are a very important part of today’s transportation system as they are bridging the gap between fully electric vehicles and conventional internal combustion vehicles (ICV’s). They have much higher efficiencies and lower emissions than ICV’s, while still having the ability to travel long range and refuel...
Many new applications of energy system devices have been developed to save energy, improve the controllability and stability of industrial processes, and reduce the weight, volume and cost of consumer devices. Due to the novelty of these devices, traditional empirical methods and lumped-parameter circuit theory methods are not sufficient for...
Advanced low power devices promote the development of micro power generators (MPGs) to replace the batteries to power them. Due to the trend in decreasing integrated circuit (IC) supply voltages, power supply designers are facing more and more serious challenges. The objective of this research is to design a power...
With the development of high performance power electronic and semiconductor technologies, Adjustable Speed Drive (ASD) systems are increasingly applied in residential, commercial and industrial applications. Due to the advantages at higher power ratings, the three-level Neutral-Point-Clamped (NPC) Voltage Source Inverter (VSI) is being employed in industrial and traction applications, static...
Advancements in power electronics to higher power levels and faster switching times allow new machine and systems designs, but also create higher stresses on electric machinery insulation. High performance, pulse-width modulated (PWM) inverters are now available for medium voltage drive systems, and are being considered by the U.S. Navy as...
Synchronous machines provide a practical way to control reactive power consumption of a plant. One of the main advantages of using synchronous motors in a plant is their ability to generate reactive power for plant loads. A new control scheme for synchronous motor excitation systems is developed to automate reactive...
With the increased attention on high efficiency and controllability of industrial processes, as well as reduced weight, volume and cost of consumer products, the applications of nonlinear power electronic converters such as adjustable speed drives (ASDs) are showing a rapid rise. Power Quality (PQ) is becoming an increasing concern with...
Power quality has become an important concern to both electric utilities and
end users due to the increased use of non-linear loads in modem power systems
over the past decade. Nonlinear loads inject harmonics into the power system and
thus may lead to poor power quality and lower power factor....
With the increased attention on high efficiency and energy savings, power electronic energy conversion equipment is increasingly incorporated in all levels of the power system. The drawback of such equipment is the generation of nonsinusoidal currents in the power distribution network due to the nonlinear operation. Harmonic currents may distort...
The harmonic problem in power systems is gaining more attention as incidences correlated with harmonics increase. Conventional passive filtering techniques for harmonic mitigation have inherent problems, and purely active filters have the disadvantages of higher costs and ratings. Hybrid active filters inherit the efficiency of passive filters and the improved...