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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
421

A Study of Experience Mapping Based Predictive Controller as Applied to Switching Converters

Nayak, Namratha January 2015 (has links) (PDF)
Experience Mapping based Prediction Control (EMPC) is a new type of controller presented in literature, which is based on the concept of Human Motor Control (HMC). During the developmental phase, called the initial learning phase, the controller records the experience in a knowledge base, through online interactions with the system to be controlled. This knowledge base created using the experience maps is termed as Experience Mapped Knowledge Base (EMK). The controller envisages the development of EMK only through interaction with the system, without the need for knowledge of the detailed plant model. The EMPC controls the system through prediction of actions based on the mapped experiences of EMK. Depending on the nature of control required for the system chosen, various strategies can be used to achieve control using the EMK. The above controller has previously been utilized for motion control applications. In the present work an effort has been made to study the suitability of the EMPC for the voltage regulation of switching converters. The plant chosen for the control study is a discontinuous conduction mode (DCM) buck converter. The parameter to be monitored for the purpose of control is the load voltage. The control input from the EMPC to the converter is a duty ratio value based pulse-width modulated (PWM) signal. Two strategies of control have been proposed: steady state control and transient control. Steady state control action maintains the steady state output voltage at the required value for a given load. The transient control action is used to improve the transient performance of the system. Iterative predictive action and iterative transient actions are used to facilitate convergence of the output voltage to within the required range in presence of non-linearities and uncertainties in the system. Impulse action is introduced to further improve the transient performance of the system. The EMPC is compared a proportional-integral (PI) controller for the given DCM buck system.
422

Analýza provozu mřížové sítě Brno – střed / Analysis of the operation of the lattice network Brno - střed

Frechová, Lucie January 2017 (has links)
The thesis shows the historical development of the South Moravian electricity system and the development of Brno´s network is discussed in more detail, especially the current form of the network from the outskirts of the city to its historical centre. The lattice network, as a subject of the analysis, is described in terms of the operation and reliability of the power supply. It also informs about the gradual development of the technology applied in the lattice network Brno-střed. The practical part performs the analysis of theoretical data and recorded data with respect to steady-state and faulty-state operation of the lattice network Brno-střed. The theoretical analysis is based on the simulation and calculation of the lattice network model in the software PAS DAISY Bizon and the monitored parameter is the transformers power load. In addition, the analysis of the real data includes the assessment of the difference average phase current values, as well as voltage, between the transformer phases. There is also the evaluation of the energy flow from the low voltage side to the high voltage side of the analysed network.
423

Zařízení pro testování diferenciálů / Device for Testing of Differentials

Odložilík, Daniel January 2021 (has links)
This master’s thesis deals with the design of equipment for testing differentials. The aim of the thesis is therefore the design of a special device that will be able to measure the steady and transient characteristics of differentials. Master’s thesis is divided into four chapters. The first chapter points out the disadvantages of fully open and closed differentials, the second deals with a basic overview of the structures and design of self-locking differentials. The third chapter deals with research of existing devices that test and measure the characteristics of differentials. The fourth chapter then discusses the possible drives of the tested unit. The fifth chapter focuses on the actual construction design of the test equipment. The subsequent sixth chapter then solves the strength calculations of the chosen structural elements of this device.
424

Návrh rekonstrukce distribuční sítě v zadané oblasti / Proposal of the reconstruction of a distribution network in a specific area

Richter, Miroslav January 2008 (has links)
The dissertation describes several types of low and high voltage distribution networks including their implementation in specified location with regards to the reliability and quality of electric power supply. The distributions networks are classified according to ways of cable routing, distribution line voltage levels as well as according to types of network interconnections. The high and low voltage distribution networks are further categorized based on used cable types, where, more attention is paid to insulated lines used in the Czech Republic, low voltage lines called „AES“ and „PAS“ high voltage lines used more and more during the distribution network reconstruction. Attention is also given to the description of used methodology for the calculation of network performance stability. An individual part of the dissertation is devoted to a low voltage distribution network proposal in the village of Kovalovice. Based on performed analysis of distribution network conditions, several reconstruction versions were proposed with the help of „KASI“ software, the description of which is also included. The proposed versions are further analysed for both, technical and economical aspects and is selected most suitable version of the distribution network.
425

Optimalizovaný termodynamický senzor na bilančním principu / Optimized Thermo-dynamic Senzor with Balance P¨rincip

Řezníček, Michal January 2008 (has links)
This work deal with taking advatage of ballance thermodynamic sensors as the replacement of commercial temperature sensors.
426

Návrh rekonstrukce distribuční sítě v dané lokalitě / Proposal of the reconstruction of the distribution network in a specific area

Novák, Vojtěch January 2009 (has links)
This diploma thesis is concerned with reconstruction of distribution network in Hruba Vrbka. The diploma thesis is divided in two parts. For better understanding to this issue, the first theoretical part is shortly dedicated to the history of electrical power system, to the several types of distribution network of low voltage and high voltage and their utilization in the area, considering the reliability and the quality of delivery of the electric energy. In this thesis there is mentioned division of distribution grids according to placing of cable lines, according to voltage and according to type of grid connection. Next part of this work is dedicated to the description of overhead lines and cable lines and their characteristics. For the proper concept of the grid we should know some characteristics of the electric line’s proposal: mechanical strength, warming, voltage drop, efficiency, degree of safety and provision of delivery. In the end of the theoretical part there are described methods for calculation of grid’s steady state as a linear task and also non-linear task, elimination of the balancing node, the iterative method, the reduction of external power take-off nodes and the solution of the steady state of the network through the direct current model. The second part of the diploma thesis is concerned with the calculation of the steady state in the village Hruba Vrbka. In this part is also described the KASI program which was used for the calculation of the grid’s steady state. Firstly low voltage grid’s balance in Hruba Vrbka was found out and evaluated and then there were proposed some solutions of the reconstruction for the grid improving. The suggested options of the reconstruction are considered from technical and economical point of view and the best solution is chosen. For this solution there is suggested the protection through program SICHR 9. In the end of this diploma thesis there is checked the load of the high voltage line.
427

Vliv decentrálních zdrojů na provozování distribuční soustavy 110 kV E.ON / The impact of distributed generation on 110 kV distribution system E.ON

Hajdú, Lukáš January 2011 (has links)
This Master´s thesis deals with problematics related to the connection of new decentralized power sources into electrical power grid. Due to advantageous legislative support of these new, especially photovoltaic power sources, a massive amount of these sources have been connected into the power grid between years 2009 and 2010. For theoretical understanding of processes during a steady-state, the initial parts of this paper are focused on a procedure which solves steady-state on every power line mentioned. When we speak of decentralized power sources connection, it is necessary to mention the connected legislative. National distribution grid operators in collaboration with national regulatory commission have decided on a legislative document Rules of distribution grid operation, which puts a set of demands and requirements on applicants wishing to connect a new power source to the grid. The text of this thesis is focused mainly on demands required after the latest change in 1/2010. Practical part of this work deals with verification of new power source influence on a related power grid and meeting the legislatively required demands. The most important demands are voltage change due to new power source operation and its transfer to other voltage levels, higher harmonics injection, power output fluctuation and last, not least, changes in load flow directions. For reasons previously mentioned an analysis is made and possibilities of reducing or removing of these influences are introduced. To achieve these goals, two computer programs, Siemens Sinaut Spectrum and NetCalc are used.
428

Posouzení možnosti připojení větrného parku Drahany 45 MW do sítě 110 kV / Evaluation of possibilities for connection of wind farm Drahany 45 MW to 110 kV network

Gregr, Tomáš January 2012 (has links)
This Master's thesis is focused on connecting of new power sources into electrical network, particularly, the steady state and allowed voltage variation in network nodes, which occur in steady state before and after connection of a new power source into distribution network, with regard to valid legislation. The new power source in question is the new wind farm Drahany with active power of 45 MW, which should be connected into distribution network 110kV, operated by distribution company E.ON. The aim of this work is to find the most suitable connection point of a wind farm into distribution network, considering transmission capacity of individual electric lines and voltage variations in network nodes, as well as Drahany wind farm's investor's expenses on construction of a connection line to connection point and the distribution network's operator's expenses on modification of the connection point. Also, methods of calculating of electric networks in steady state are described in this paper, particularly, linear calculations, because these are needed for the calculations in E-vlivy program, in which the possible options of Drahany wind farm's connection into network 110 kV, in various places, were modeled. The description of the E-Vlivy program is also included in this paper. The E.ON company's materials form the basis for this Master's thesis, which will later serve as one of the documents needed for Drahany wind farm’s connection point evaluation into distribution network 110 kV.
429

Ustálený chod a zkratové poměry v síti 110 kV E.ON při paralelním provozu uzlových oblastí R Čebín a R Sokolnice / Steady state and short-circuit conditions within E.ON 110 kV power network at parallel operation of nodal areas of Čebín substation and Sokolnice substation

Múdry, Peter January 2013 (has links)
In the distribution network 110 kV of E.ON Company there are the nodal areas of Čebin substation and Sokolnice substation which are operated separately at the present time. There is one 400/110 kV transformer for each nodal area. In case of fault on one of these transformers or on busbar in which the set transformer is working, it comes to an outage of electric supply in the set nodal area. This problem has to be solved with help of the parallel operation of nodal areas of Čebín substation and Sokolnice substation. The main and also the practical task of this work is to design the bridge connection appropriate for parallel operation of nodal areas (supply transformers 400/110 kV). With help of a computing program there were made calculations of steady state and short-circuit conditions in distribution network 110 kV for separated and parallel operation of nodal areas. Voltage conditions, load of transformers (400/110 kV and 110/vn kV) and conditions on 110 kV lines are evaluated and controlled as the result of steady state calculations. Based on short-circuit conditions there is controlled the short-circuit resistance of the substations. Finally there are compared advantages and disadvantages of separated and parallel operations of nodal areas. If necessary, technical arrangements required for introduction of parallel operation of nodal areas of Čebín substation and Sokolnice substation will be designed. The theoretical part of the work deals with calculation of steady state with help of iterative methods, namely Newton´s and Gauss-Seidel methods. There are further described the method of calculating short-circuit currents, characteristic values and time behaviours of short-circuit current.
430

Návrh úprav a konfigurace sítě 22 kV po instalaci transformace 110/22 kV ve spínací stanici Brno-sever / Proposal of design and configuration of 22 kV network after installation of 110/22 kV transformation in Brno-Sever switching substation

Mišinger, Ondřej January 2013 (has links)
The theoretical part of this thesis deals with distribution networks in terms of distribution according to different criteria, describes the main elements of electric distribution networks and their qualities. The following describes the methods of calculating the steady state of electrical networks. These methods are nowadays used as basics for computer programs. In the penultimate chapter of the theoretical part are summarized the principles for the development of present networks and construction of new electrical networks. The aim of practical part of the thesis is to assess the current condition of the network 22 kV in the city of Brno and assess the condition after installation of 110/22 kV transformation in Brno-Sever switching substation. After evaluating the results of steady state electrical network and identifying certain problems is the following aim a proposal of solving problems that emerged in the network. The result should be operational, functional and reliable electric distribution network. This thesis used to calculate the steady state electrical networks by software PAS DAISY Off-Line Bizon V4.

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