Káosz elméleti kutatás véges számú teljesitmény kapcsolókat tartalmazó, nemlineáris. dinamikus, szabályozott rendszerekben = Research with Chaos Theory in Nonlinear, Dynamic, Feedback Controlled Systems Containing Finite Number of Power Switches

A kutatás négy témakörben folyt. Kaotikus tartományban működő nemlineáris villamos hajtás stabilis trajektóriára állítása témában a legfontosabb eredmény az volt, hogy a motor árammal arányos jelhez külső periodikus fűrészfog alakú jelet adva el lehetett érni a jel meredekségének megváltoztatásával, hogy a rendszerre ható külső jelek (terhelő nyomaték, tápfeszültség, fordulatszám alapjel) terének egy általunk megválasztott széles tartományában a rendszer stabilis maradjon, míg ugyanitt a fűrészfog alakú jel nélkül a rendszer kaotikus, labilis állapotba került. A megújuló energiák témában az ultranagy fordulatszámú gép szabályozásával, egy új kombinált napelem-termikus rendszer elméleti, szimulációs és kísérleti vizsgálatával és a mikrogridek feszültségszabályozásával foglalkoztunk. A pulzus szélesség modulációs eljárásokkal kapcsolatban egyes irodalmi állításokkal szemben bizonyítottuk, hogy jelentős egyenáramú komponens is felléphet. Francia, olasz és japán kooperációban végzett kutatás során a konverterek által generált harmonikusokat csökkentő két módszert dolgoztuk ki. Az eredményeket 45 cikkben publikáltuk. Egy kivételével valamennyi angol nyelvű és három kivételével valamennyi külföldön jelent meg Európa, Amerika, Ázsia és Afrika országaiban. | The research has had four topics. The most important result in the topic dealing with the connection to a stable orbit of a chaotic trajectory of nonlinear electrical drive operating in chaotic region was as follows: The system remain stable in wide range of the input signals (load torque, supply voltage, speed reference signal) selected by us provided that, the slope of an input periodical saw tooth signal added to the signal proportional to the motor current has been change. Otherwise the system remained operating in chaotic state without the application the saw tooth signal. In the renewable energy topic the control of ultra-high speed machine and the theoretical and simulation, test of the new combined solar-thermal system as well as voltage control of micro-grids were the research fields. Contrary to the statements found in the relevant literature dealing with the pulse width modulation it has been proved that considerable amount of DC-DC current can be generated. Two methods for suppressing harmonics generated by the electrical energy conversion have been developed in French, Italian, and Japanese cooperation. The research results have been published in 45 papers. All of them but one was written in English and they were published outside of Hungary in Europe, Asia, America, and Africa except three of them

Simulation of Processes in Dual Three-Phase System on the Base of Four Inverters with Synchronized Modulation

Novel method of space-vector-based pulse-width modulation (PWM) has been disseminated for synchronous control of four inverters feeding six-phase drive on the base of asymmetrical induction motor which has two sets of windings spatially shifted by 30 electrical degrees. Basic schemes of synchronized PWM, applied for control of four separate voltage-source inverters, allow both continuous phase voltages synchronization in the system and required power sharing between DC sources. Detailed MATLAB-based simulations show a behavior of six-phase system with continuous and discontinuous versions of synchronized PWM

Synchronous PWM control of four inverters feeding asymmetrical six-phase motor drive

Novel method of space-vector-based pulsewidth modulation (PWM) has been disseminated for synchronous control of four inverters feeding six-phase drive on the base of asymmetrical induction motor which has two sets of windings spatially shifted by 30 electrical degrees. Basic schemes of synchronized PWM, applied for control of four separate voltage source inverters, allow both continuous phase voltages synchronization in the system and required power sharing between DC-sources. Simulations show a behavior of sixphase system with continuous and discontinuous versions of synchronized PWM

POWER ELECTRONIC SYSTEM FOR POWER ELECTRIC VEHICLES WITH ALGORITHMS OF SYNCHRONOUS MODULATION

Schemes of synchronous space-vector modulation have been adapted for control of split-phase drive for electric vehicle with open-end windings of induction motor, supplied by several voltage source inverters. MATLAB-based simulation of processes in this system has been executed. It has been shown, that the use of algorithms of synchronous modulation provides symmetry of phase voltage waveforms for any ratio between the switching frequency and fundamental frequency, and for any voltage magnitudes of dc-sources. Spectra of the phase voltage of system do not contain even harmonics and subharmonics (of the fundamental frequency), which is especially important for drives for the medium-power and high-power electric vehicles

Basic schemes of synchronized pulsewidth modulation for cascaded inverters of drive system with two DC-sources

Continuous and discontinuous schemes of synchronized pulsewidth modulation (PWM) have been applied for control of an open-end winding motor drive fed by cascaded inverters supplied by two dc-sources with non-equal voltages. Simulations illustrate behavior of these systems with algorithms of synchronized PWM. Spectra of multilevel phase voltage of open-end winding motor drives with synchronized PWM do not contain even harmonics and sub-harmonics during the whole control range, which is especially important for the medium-power and high-power systems.Представлены результаты исследования и моделирования режимов работы системы электропривода на базе асинхронного электродвигателя с разомкнутыми обмотками, подключенными к сдвоенным инверторам напряжения с синхронной модуляцией непрерывного и прерывистого типа, питающихся от двух изолированных источников постоянного напряжения. Показано, что в спектре многоуровневого фазного напряжения подобных систем с алгоритмами синхронной широтно-импульсной модуляции на всем диапазоне регулирования отсутствуют четные гармоники и субгармоники, что представляется особенно важным для преобразовательных систем повышенной мощности.Представлено результати дослідження та моделювання режимів роботи системи eлектроприводу на базі асинхронного електродвигуна з розімкненими обмотками, які підключено до подвоєних інверторів напруги з синхронною модуляцією неперервного та пeреривчастого типу, що живляться від двох ізольованих джерел постійного струму. Показано, що у спектрі багаторівневої фазної напруги таких систем з алгоритмами синхронної широтно-імпульсної модуляції у всьому діапазоні регулювання відсутні парні гармоніки та субгармоніки, що є найважливішим для перетворювальних систем підвищеної потужност

Renewable Energy

Renewable Energy is energy generated from natural resources - such as sunlight, wind, rain, tides and geothermal heat - which are naturally replenished. In 2008, about 18% of global final energy consumption came from renewables, with 13% coming from traditional biomass, such as wood burning. Hydroelectricity was the next largest renewable source, providing 3% (15% of global electricity generation), followed by solar hot water/heating, which contributed with 1.3%. Modern technologies, such as geothermal energy, wind power, solar power, and ocean energy together provided some 0.8% of final energy consumption. The book provides a forum for dissemination and exchange of up - to - date scientific information on theoretical, generic and applied areas of knowledge. The topics deal with new devices and circuits for energy systems, photovoltaic and solar thermal, wind energy systems, tidal and wave energy, fuel cell systems, bio energy and geo-energy, sustainable energy resources and systems, energy storage systems, energy market management and economics, off-grid isolated energy systems, energy in transportation systems, energy resources for portable electronics, intelligent energy power transmission, distribution and inter - connectors, energy efficient utilization, environmental issues, energy harvesting, nanotechnology in energy, policy issues on renewable energy, building design, power electronics in energy conversion, new materials for energy resources, and RF and magnetic field energy devices

Acoustic Waves

The concept of acoustic wave is a pervasive one, which emerges in any type of medium, from solids to plasmas, at length and time scales ranging from sub-micrometric layers in microdevices to seismic waves in the Sun's interior. This book presents several aspects of the active research ongoing in this field. Theoretical efforts are leading to a deeper understanding of phenomena, also in complicated environments like the solar surface boundary. Acoustic waves are a flexible probe to investigate the properties of very different systems, from thin inorganic layers to ripening cheese to biological systems. Acoustic waves are also a tool to manipulate matter, from the delicate evaporation of biomolecules to be analysed, to the phase transitions induced by intense shock waves. And a whole class of widespread microdevices, including filters and sensors, is based on the behaviour of acoustic waves propagating in thin layers. The search for better performances is driving to new materials for these devices, and to more refined tools for their analysis

Princeton Plasma Physics Laboratory annual report, October 1, 1993-- September 30, 1994

The Tokamak Fusion Test Reactor (TFTR) project is well into the experimental phase of its deuterium-tritium (D-T) program, with the objective to derive the maximum amount of experimental data on the behavior of tokamak plasmas containing a significant population of energetic alpha particles. Since the initial D-T experiments in December 1993, the operational performance of the TFTR, as well as the required tritium-handling and machine maintenance procedures in an activated environment, have improved markedly, so that D-T operation has now become essentially routine, while fully conforming with all of the safety and environmental requirements. During the D-T phase, the machine and auxiliary-systems parameters have also been increased, most notably the toroidal field (to 5.6 T) and the neutral-beam power (to 40 MW). The radio-frequency power in the ion-cyclotron-range of frequencies (ICRF) has been increased to 11 MW