A closed system of fluid equations to describe the evolution of a weakly collisional toroidal plasma is presented. The primary physical phenomena incorporated are gyration, guiding center motion, and parallel flows of particles and heat. The systematic use of the drift ordering allows for faster dynamics that in a transport context, and in order to capture important spatial variation, no flux-surface average is taken. A notable feature of this model is a generalized bootstrap current: applying the neoclassical limit and flux-surface average to the expression for the parallel current annihilates more general terms, leaving the canonical bootstrap current as the result. Thus, the model reduces to neoclassical transport in the proper limit, but generally includes more physical effects.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (M.A.)--Ball State University, 2009. / Title from PDF t.p. (viewed on July 12, 2010). Research paper (M.A.), 3 hrs. Includes bibliographical references (p. 42-43).

Call number: LD2668 .T4 1966 S562 / Master of Science

A Superconducting Magnetic Energy Storage (SMES) system is a very efficient storage device capable of storing large amounts of energy. The primary applications it has been considered till now are load-leveling and system stabilization.This thesis explores new applications/benefits of SMES in power systems. Three areas have been identified. • Using SMES in conjunction with PV systems.SMES because of their excellent dynamic response and PV being an intermittent source complement one another.A scheme for this hybrid system is developed and simulation done accordingly. • Using SMES in an Asynchronous link between Power Systems. SMES when used in a series configuration between two or more systems combines the benefits of asynchronous connection, interconnection and energy storage. A model of such a scheme has been developed and the control of such a scheme is demonstrated using the EMTP. The economic benefits of this scheme over pure power interchange, SMES operation alone and a battery/dc link is shown. Improvement of transmission through the use of SMES. SMES when used for diurnal load leveling provides additional benefits like reduced transmission losses, reduced peak loading and more effective utilization of transmission facility, the impact of size and location on these benefits were studied, and if used as an asynchronous link provides power flow control. / Master of Science

No description available.

In this study, a model is developed to represent doubly-salient magnetic circuits and to fit finite element analysis for the aim of obtaining a set of normalized normal force, tangential force, and permeance variation data. To obtain the desired data FE field solution method is used. The reliability of finite element results have been verified by three steps / first, comparing the numerical results with analytically calculated permeance, second, by solving two switch reluctance motors and comparing the results with the measurements of static torque and flux linkage. The third step is by using the normalized data obtained by solving the model with the aid of an available software that is capable to predict the behavior of switched reluctance motors. Once the reliability of the data is assured, the desired data set is produced and presented in tables.

The extensive use of nonlinear loads in today’s world has inspired considerable research interest in the area of power quality improvement. This thesis proposes an integrated magnetics based compact solution which provides regulated, balanced and sinusoidal load voltage drawing sinusoidal and balanced currents from the grid. Thus, it supplies clean power to the load without polluting the grid. It consists of an EI shaped magnetic core and two compensators known as the series and shunt compensators. The series compensator ensures the quality of output voltage, where as the shunt one takes care of quality of the current drawn from the grid. The magnetic circuit acts as a common domain for interaction between the energy ports. It also provides galvanic isolation between the inverters, load and the grid. The magnetic circuit incorporates a virtual arm switching mechanism to have an option of connecting the inverters either in series or in parallel with each other depending on the requirements. During normal mode when the switch remains inactive, the series inverter is effectively in series with the load and the shunt inverter is effectively connected across the load. Therefore, the voltage source inverters can be independently controlled to serve the purpose of series and shunt compensation. The shunt inverter is always connected in shunt with the grid. The magnetic arm switch is activated during grid power failure. Then the switch ensures parallel connection of the inverters and the load. The inverters are controlled to share the load power according to the respective ratings. Thus the magnetic arm switching mechanism helps in improving the system reliability. The series inverter also can be connected in parallel with the shunt one in presence of the grid to supplement the shunt inverter by supplying harmonic and reactive currents. The design, modelling and implementation issues for single phase applications are considered first. A simple controller structure for this application is also discussed in the thesis. The individual compensation actions are then verified by simulation and experimental results. The three phase power quality compensator is in principle an extension of the single phase quality power supply. It is realized by combining three single phase units with minor modification in terms of windings. A more compact structure is also proposed wherein a single integrated magnetic circuit for the three phase application can be used. The composite magnetic circuit is modelled and designed considering a laboratory prototype. A synchronously rotating reference frame based controller structure for the series and shunt compensators are discussed. The control of the inverters in power sharing mode (with parallel connected inverters) are also proposed and discussed. Experimental and simulated results are presented to verify and validate the operation of this compensator in different operating modes. An effective improvement in the control dynamics is achieved for handling unbalanced and nonlinear loading without increasing inverter switching frequency and controller parameters. In other words, the modified control scheme can handle nonlinear and unbalanced loading with relatively slow proportional integral (PI) controllers. Suitable feed forward compensation terms corresponding to each harmonic component are added to the output of the PI controllers in order to achieve this effective improvement. Experimental results show good improvement in this regard (for both series and shunt compensations).

The first part of this thesis deals with the basic division of magnetic circuits and materials which are used for their construction. The next section focuses on the description of losses in the magnetic circuit. There is a description of hysteresis losses and eddy losses. The chapter contains the theoretical basis for the mathematical description of hysteresis and eddy losses. There is an analysis of the losses caused by the first harmonious and additional losses caused by harmonics. The third part describes the measurement of losses in ferromagnetic materials. There are all methods that are used. The fourth and fifth chapter is devoted to practical measurement hysteresis losses 1. phase transformer and measuring eddy losses in the inductor using the pulse method.

CNPq / Este trabalho apresenta o estudo de um método para a determinação da posição e orientação de uma bobina implantável em relação à bobina transmissora localizada externamente ao paciente. No aspecto elétrico, conhecer a posição e orientação da bobina implantada permite um maior domínio sobre o posicionamento do enlace e, consequentemente, das características de eficiência e potência entregue ao secundário, i.e. ao IMD. Já no aspecto clínico, detectar e determinar a posição da bobina implantável e, se possível, do IMD, pode auxiliar na determinação de possíveis movimentações do dispositivo na região implantada que podem influenciar o seu desempenho. Neste sentido, realizou-se análises teóricas a cerca da indutância mútua, do coeficiente de acoplamento magnético e de sistemas de transferência de energia sem fio (WPT) a duas bobinas. Por meio do modelo matemático implementado no software Matlab e o projeto experimental de sistemas de WPT a duas bobinas, avaliou-se a influência de desalinhamentos laterais e angulares sobre o acoplamento magnético. A partir das características observadas, descreveu-se os procedimentos necessários para estimar a posição e orientação relativa da bobina do dispositivo implantável apenas mensurando os parâmetros elétricos do primário. Em uma avaliação preliminar, por meio de testes virtuais, observou-se um erro médio e incerteza padrão na determinação da posição relativa de 2,4 mm e 1,1 mm, respectivamente, que se comparada às dimensões das bobinas (40 mm de diâmetro para bobina externa e 5,5 mm para a bobina implantável) indicam uma exatidão adequada. Para a determinação do ângulo relativo o método também apresentou resultados promissores, uma vez que o erro médio foi de 7º e a incerteza padrão obtida de 8,2º. Desta forma, o método estudado possibilita o desenvolvimento de equipamentos para determinação da posição e orientação relativa de uma bobina implantável mensurando apenas a corrente no primário, sem a necessidade de circuitos adicionais no IMD ou a utilização de equipamentos de imagem médicos. / This paper presents the study of a method for determining the implanted coil position and orientation relative to the transmitter coil externally located to the patient. In the electrical aspect, knowing the implanted coil position and orientation allows greater control over the placement of the link and thus the efficiency of features and power delivered to the secondary, i.e. the IMD. In the clinical aspect, detect and determine the implantable coil position, if possible, the IMD can assist in determining possible device movements in the implanted area that can influence their performance. In this sense, a theoretical analysis about the mutual inductance, the magnetic coupling coefficient and two coils wireless power transfer (WPT) systems was realized. Through mathematical model implemented in Matlab and experimental design of two coil WPT systems, the influence of lateral and angular misalignment on the magnetic coupling was assessed. From the observed characteristics, was described the necessary procedures to estimate the relative position and orientation of the implantable device coil only measuring the primary electrical parameters. In a preliminary evaluation, through virtual testing, there was an average error and standard deviation in determining the relative position of 2.4 mm and 1.1 mm, respectively, compared to the dimensions of the coils (40 mm diameter to external coil and 5.5 mm for implantable coil) indicate adequate accuracy. To the relative angle the method also yielded promising results, since the average error was 7° and the standard deviation obtained 8.2°. Thus, the method studied enables the development of equipment for determining the implanted coil relative position and orientation measuring only the primary current without the need for additional circuitry in IMD or the use of medical imaging equipment.