Horizontal stratification of the soil in multi-layer using non-linear optimization

O propósito principal deste trabalho é apresentar uma metodologia de otimização utilizando um processo de otimização não-linear na obtenção dos parâmetros da estratificação horizontal do solo em várias camadas. O método utiliza uma curva de resistividade experimental proveniente de leituras feitas no solo, esta curva experimental é comparada com uma outra curva de resistividade teórica produzida pelo processo de otimização. A curva teórica é embasada no algoritmo de Sunde e é exatamente o processo inverso da estratificação horizontal do solo em várias camadas. De posse das duas curvas, pode-se mensurar o erro produzido na estratificação horizontal do solo. Os parâmetros a serem estimados utilizando o algoritmo genético são os números de camadas N, a resistividade Roi e a espessura hi de cada camada

Efficiency Improvement of Switched Reluctance Generator Using Optimization Techniques

This article introduces the switched reluctance machine operating as a generator. This kind of electrical machine delivers CC power at the output and the energy generated can be controlled through several variables. In this work, the switching angles of the machine's power converter are optimized using deterministic and heuristic techniques so that the output power is kept constant via PI controller while guaranteeing maximum value for machine performance, even for different excitation values and mechanical power on the shaft

Efficiency Improvement of Switched Reluctance Generator Using Optimization Techniques

This article introduces the switched reluctance machine operating as a generator. This kind of electrical machine delivers CC power at the output and the energy generated can be controlled through several variables. In this work, the switching angles of the machine's power converter are optimized using deterministic and heuristic techniques so that the output power is kept constant via PI controller while guaranteeing maximum value for machine performance, even for different excitation values and mechanical power on the shaft

Estimate of Geopressures using Conformal Mapping in Eccentrical Wellbores

The purpose of this work is to calculate Surge and Swab pressure in oil wells with eccentricity between drill string and wellbore or casing string. Analysis of this phenomenon, in which the fluid is confined between two eccentric cylinders, are made. The conformal mapping is used to lead the eccentric domain into the concentric domain, since the usual models correspond to concentric geometries. The results of this study, using the proposed methodology, are presented and discussed

Analysis and monitoring of electrical grounding grid encapsulated with concrete: case study using simulation in finite element method

This work study the influence of concrete, plaster, clay and others buried structures in grounding systems. Comparison of soil characteristics between dry and rainy seasons on different grounding systems. The study includes comparison of six different grounding system on dry season and wet season. Simulations in finite element method was performed for tree layer stratified soil and the electrostatic equipotential surfaces were mapped into the region of interest

Geoelectric method applied in correlation between physical characteristics and electrical properties of the soil

This paper presents the study of the relationship between electrical properties and physical characteristics of the soil. Measures of apparent electrical resistivity of the soil were made for different types of soil, varying moisture content gradually while maintaining a constant compaction, and then varying the compaction and relating it to a constant humidity. Development of a correlation surface is proposed in order to identify granulometry of the soil from moisture and compaction measurements. For the study of spatial variability, two areas were chosen to allow the change of moisture content and compaction in order to verify the measurement capacity of apparent electrical resistivity of the soil as methodology to identify change in soil dynamics. Results obtained show correlations among apparent electrical resistivity of the soil, moisture, soil compaction and clay content

Hybrid Optimization Process Applied to Tuning of Dynamic Matrix Control: Study Case with DC Motor

This paper presents study about Dynamic Matrix Control (DMC) controller applied to speed control of DC motor. DMC controller parameters (prediction horizon, control horizon and damping rate of reference) are obtained through optimization methods employing heuristic, deterministic and hybrid strategies. The use of advanced control technique combined with using of optimization methods aims to achieve highly efficient control, reducing the transient state period and variations in steady state. These methods were applied on a simulation model in order to verify which one provides better control results.   Index Terms—Predictive Control, Deterministic Optimization, Heuristic Optimization, Hybrid Optimization, DC motor

Estimativa das Indutâncias de uma Máquina Síncrona a partir de Ensaio com Rotor Bloqueado

Este trabalho apresenta uma simulação computacional da máquina síncrona de pólos salientes (SPSM), utilizando as indutâncias obtidas experimentalmente dos enrolamentos do estator e do rotor. Para obter as indutâncias e suas derivadas utiliza-se o método Volt-Ampere implementado em um módulo de aquisição de dados. Uma rotina computacional é desenvolvida para realizar a simulação da máquina, que irá funcionar como gerador em sincronismo com a concessionária de energia elétrica. Para validar o método proposto, os resultados das medições de correntes obtidos nos terminais da máquina são comparados com os resultados obtidos na simulação em condições semelhantes de funcionamento

Reconditioning in synchronous operation with one parallel induction generator

The purpose of this paper is to compare mathematical modeling and practical bench in order to validate the electrical interactions between an induction generator and a synchronous generator. Two generators was connected to a common bus in steady state, subject to non-linear load. The results comparing modeling and bench tests show that the induction generator besides the active power increasing, has a better way for harmonic currents flowing in common bus. It was concluded that the induction generator repowering and attenuates current harmonic components present at the connection point, improving the network voltage profile