Made available in DSpace on 2014-12-17T14:55:08Z (GMT). No. of bitstreams: 1 FranciscoAFM.pdf: 1422041 bytes, checksum: 5ba006636ee4d36b274ed24d386fab11 (MD5) Previous issue date: 2007-12-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / At present, the electricity generation through wind energy has an importance growing in the world, with the existence of very large plans for future wind power installation worldwide. Thus, the increasing the electricity generation through wind power requires, more and more, analysis of studies of interaction between wind parks and electric power systems. This paper has as purposes to implement equivalent models for synchronous wind generators to represent a wind park in ATP program and to check behavior of the models through simulations. Simulations with applications of faults were achieved to evaluate the behavior of voltages of system for each equivalent model, through comparisons between the results of models proposed, to verify if the differences obtained allows the adoption of the simplest model / A gera??o de eletricidade atrav?s da energia e?lica teve, recentemente, um importante crescimento em todo planeta, com a exist?ncia de v?rios planos de instala??es de pot?ncia e?lica para o futuro. Dessa forma, o aumento na gera??o de eletricidade atrav?s da energia e?lica requer, cada vez mais, an?lise de estudos da intera??o entre os parques e?licos e os sistemas el?tricos de pot?ncia. Este trabalho tem como objetivos implementar modelos equivalentes de aerogeradores s?ncronos para representar um parque e?lico no programa ATP e examinar o comportamento dos modelos atrav?s de simula??es. Simula??es com aplica??es de faltas foram realizadas para avaliar o comportamento das tens?es do sistema para cada modelo equivalente, atrav?s de compara??es entre os resultados dos modelos propostos, para verificar se as diferen?as obtidas permitem a ado??o do modelo mais simples

This dissertation addresses attitude control and inertial navigation of autonomous underwater vehicles (AUVs). We present theoretical justification for using simplified models, derive system identification algorithms, and verify our results through extensive field trials. Although this research focuses on small AUVs with limited instrumentation, the results are useful for underwater vehicles of any size. For attitude control of aircraft systems, second-order equivalent pitch-axis models are common and extensively studied. However, similar analysis has not been performed for the pitch-axis motion of underwater vehicles. In this dissertation, we study the utility and the limitations of second-order approximate models for AUVs. We seek to improve the flight performance and shorten the time required to re-design a control algorithm when the shape, mass-distribution, and/or net buoyancy of an AUV/payload configuration changes. In comparison to commonly implemented AUV attitude controllers, which neglect roll motion and address pitch and yaw dynamics separately, we derive a novel linear time-varying model that explicitly displays the coupling between pitch and yaw motion due to nonzero roll angle and/or roll rate. The model facilitates an Hâ control design approach that explicitly addresses robustness against those coupling terms and significantly reduces the effect of pitch and yaw coupling. To improve AUV navigation, we investigate algorithms for calibrating a triaxial gyroscope using angular orientation measurements and formally define AUV trajectories that are persistently exciting and for which the calibration coefficients are uniformly observable. To improve AUV guidance, we propose a near real-time ocean current identification method that estimates a non-uniform flow-field using only sparse flow measurements. / Ph. D.