Теоретичні основи електротехніки[

The Theory of Electrical Engineering is presented in three parts: the Basic Theories of Steady-State and Transients in Electrical Circuits and the Basic Theory of Electromagnetic Field. For students of electrotechnical specialties of higher educational establishments, as well as for scientific and technical specialists dealing with modern problems in the theory and practice of electric power engineering and electromechanics.Викладено теоретичні основи електротехніки в трьох частинах: теорія стаціонарних процесів в електричних колах, теорія перехідних процесів в електричних колах і теорія електромагнітного поля. Для студентів електротехнічних спеціальностей вищих навчальних закладів, а також для науково-технічних фахівців, що займаються сучасними проблемами в теорії і практиці електроенергетики та електромеханіки

Transient electrothermal simulation of power semiconductor devices

In this paper, a new thermal model based on the Fourier series solution of heat conduction equation has been introduced in detail. 1-D and 2-D Fourier series thermal models have been programmed in MATLAB/Simulink. Compared with the traditional finite-difference thermal model and equivalent RC thermal network, the new thermal model can provide high simulation speed with high accuracy, which has been proved to be more favorable in dynamic thermal characterization on power semiconductor switches. The complete electrothermal simulation models of insulated gate bipolar transistor (IGBT) and power diodes under inductive load switching condition have been successfully implemented in MATLAB/Simulink. The experimental results on IGBT and power diodes with clamped inductive load switching tests have verified the new electrothermal simulation model. The advantage of Fourier series thermal model over widely used equivalent RC thermal network in dynamic thermal characterization has also been validated by the measured junction temperature

Investigations on Joule heating applications by multiphysical continuum simulations in nanoscale systems

This work furthers the overall understanding of a 3w-measurement, by considering previously unexamined macroscopic influence factors within measurement by Finite Element simulations (FES). Moreover, new measuring configurations are developed to determine (an)isotropic thermal conductivities of nanoscale samples. Since no analytic solutions are available for these configurations, a new evaluation methodology is presented to determine emergent thermal conductivities by FES and Neural Networks

Electroquasistatic sensors for surface and subsurface nano-imaging of integrated circuit features

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Includes bibliographical references (p. 137-138).The following thesis relates to the design, simulation, and testing of electroquasistatic (EQS) sensors to be used for feature/defect location and imaging. The aim of this thesis is to launch an investigation into the use of EQS sensor arrays for non-destructive evaluation and quality control purposes for integrated circuit industry applications. Research into three specific areas serves as the primary focus of the thesis: 1.) The use of EQS sensors to penetrate the surface of doped silicon and locate p-n junctions and doped wells. Arrays of coplanar EQS sensors are scanned laterally over the surface of a doped silicon bulk at a fixed scan height. Electric fields from the driven EQS sensor array are capable of penetrating the surface of the semiconductor when sensors are operated at a frequency comparable to its charge relaxation break frequency. It is demonstrated through finite element method (FEM) simulations that voltage-driven EQS electrodes can couple into the p-n junction without making any direct electrical contact with the semiconducting bulk. A new methodology for locating p-n junctions is presented where the currents on these voltage-driven sensors are monitored for harmonic distortion due to the junction's nonlinear drift/diffusion carrier dynamics. With sensors located over a p-n junction at a scan height of 200 nm and driven at 1GHz, the ratio of the second harmonic current to the fundamental current on a sensor is shown to exceed 9%. Such an IC imaging technique could prove to be useful for verification and detection of fabrication errors, externally monitoring current flows, as well as detecting hidden Trojan circuits that might be present. 2.) The use of EQS sensors to locate and image surface features and contaminant objects on photomasks. Motivation for research into this area comes from the desire to be able to locate and remove contaminant particles that might be present on extreme ultraviolet lithography (EUVL) photomasks used in the mass production of next-generation integrated circuits. FEM simulation results demonstrate the sensitivity of EQS sensor arrays in detecting various contaminant particles located in a 100nm wide by 70nm deep gap in the absorber layer of an EUVL photomask. A millimeter-scale, in-lab experiment using capacitive sensors is performed with sensors and materials having similar aspect ratios and electrical properties to those simulated. Experiments demonstrate both the capabilities and limitations of sensors in detecting various objects located in a trenches milled out of aluminum. Additionally, a discussion of the need for low-noise pickup circuitry to interface with sensors is presented. 3.) An investigation into the inversion of sensor transimpedance response signals into predicted feature/defect profiles. In this case study, an inverse electromagnetic sensor problem is solved by training a radial basis function artificial neural network (RBF-ANN) to accurately approximate the forward mapping of the physical dimensions (width and depth) of a high aspect ratio trench in doped silicon into a sensor's transimpedance response as the sensor array scans past the trench at a fixed scan height. This is an example of the type of inverse problem that might be encountered in an EQS array microscope and one possible approach to its solution. The function-approximation network is then inserted into an iterative signal inversion routine which converges to a prediction for the trench's dimensions, given a measured transimpedance response. The routine is capable of predicting trench dimensions to within 1% of their actual value. In all three cases, research involves extensive finite element method (FEM) simulations of sensor performance using COMSOL Multiphysics.by Benjamin L. Cannon.S.M

Energy flow in nonlinear circuits

Apparent power and reactive power are two critical quantities in energy flow studies in electrical power systems. Existing definitions for these terms work well when both voltages and currents are sinusoidal with respect to time. However, both apparent and reactive power have no physical meaning. When these physically unclarified quantities are applied to non-sinusoidal systems, the following questions related to power flow remain not fully answered to date. What do these quantities really mean? Is it fair to bill customers based on the measurement of physically not meaningful quantities? What is the efficient way, both economical and technical, to compensate non-active power in power networks?;To answer the above mentioned questions, this thesis analyzes energy flow in nonlinear circuits, clarifies and proposes new power quantities with physical interpretations that are practical and effective when voltages and/or currents are non-sinusoidal. The suggested definitions are measurable quantities based on time-domain approach, and are useful in evaluating the power quality and efficiency in electrical systems. The measurement method and compensation with active filters are also discussed

Design of an All-dielectric Sublayer for Enhanced Transmittance In Stacked Antenna Array Applications

In spatially constrained applications, the overlapping of antenna arrays can be unavoidable and its presence can lead to a blockage in the line-of-sight for the underlying antennas. Although previous investigations focused predominantly on the contribution of the ground plane and feed network-which were resolved through the use of frequency selective surfaces and proper feed network design, respectively-it is believed that the ground plane, substrate, and patch regions can emplace a substantial combined impedance. To rectify the transmission through these layers, an all-dielectric implementation is suggested based on the properties of complementary media and Fabry-Perot resonance shifting phenomena. Consequently, both spherical inclusion based dielectric metamaterials and regular dielectrics are suggested, such that additional conductive losses are avoided and surface wave coupling becomes less plausible; while making possible both negative and positive refractive indices. The transfer matrix method and effective medium theory are jointly implemented to examine the required properties of the dielectric or metamaterial sublayer on the basis of providing a transmittance on the order of a known high transmittance analog. Mie theory provides the basis behind the effective properties of the spherical inclusion based metamaterial whereby the required dimensions and permittivity can be determined by a sequential quadratic programming optimization in MATLAB. It is found that the metamaterial emplaces constraints on fabrication which are not currently feasible. Therefore, the equally practicable positive refractive index solutions in a regular dielectric are proposed as the most viable alternative and utilized to determine a functional bandwidth

Modeling studies to evaluate performance of the horizontal wells completed in shale

The results of the modeling studies to determine the production performance of multiple fractured horizontal wells completed in shale formation has been summarized in this dissertation. A commercial reservoir simulator was utilized to model both single and dual porosity reservoir (with and without adsorption) with multiple layers. The impact of reservoir characteristics including natural fractures and hydraulic fractures properties on the production performance were investigated. In addition, the results were utilized to investigate the flow regimes for horizontal wells with one or multiple hydraulic fractures.;Flow regime identification in low permeability reservoirs is extremely critical to evaluate performance of the horizontal wells. In this research, a number of possible flow regimes were identified using both log-log plot of inverse of the flow rate and its derivative versus time. They included linear, tri-linear (second linear), and pseudo-steady state. In addition, Decline Curve Analysis (DCA) and Production Type Curves (PTC) were also considered in this study to confirm the observed flow regimes and their production behavior. The results of this study will provide an understanding of flow behaviors in low permeability reservoirs. Understanding of the flow behavior can then be used to predict production from low permeability reservoirs such as Marcellus shale