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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.
31

Analysis of a load frequency control implementation in Swedish run-of-river hydropower stations

Westberg, Andreas January 2012 (has links)
The total amount of frequency deviations have during the last decade increased exponentially in the Nordic synchronous power system. The transmission system operators have therefore decided to implement load frequency control as a new automatic control system to stem these frequency deviations. The aim of this feasibility study is to analyse the effects of an LFC implementation in Swedish hydropower stations by using a more dynamic river governing. The method chosen to analyse the effects of LFC-governing was to create a Matlab Simulink hydropower station library including dynamic modules for rivers and turbine governors. The library is then used to create a river reach that is implemented in an ENTSO-E model for the Nordic frequency reserves. The governing of the river uses economical dispatch theory to optimally distribute a LFC setpoint signal from the ENTSO-E model to the different hydropower stations. Results show that the developed method has a future potential to create more frequency controlled reserves. By creating a central governing unit it was possible to govern frequency controlled reserves over an entire river reach under certain scenarios, but there are still many obstacles to overcome before an actual implementation. The method does however show both the possibilities and drawback of frequency controlled reserves in cascade coupled hydropower systems.
32

Transmission Modeling with Simulink and FPGA implementation of 3072-point FFT for the Homeplug AV system

Sun, Wei-Cheng 20 July 2011 (has links)
The rapid growth of communication technology with the success of internet, has brought huge profits and great convenience to our daily life. Computer networks can be built using either wired or wireless technologies. It will be an important issue that how to select a medium for the transmission. Wired Ethernet has been the traditional choice in most of the networks. However, it has to deploy the Ethernet wires. For the wired internet networks, the power line communication (PLC) technology will be an alternative choice. In this wire-line communication system, the power line network is used as the transmission medium. Therefore, computer networks can work on the existing power line system. No extra new transmission infrastructure is needed. So far, several PLC standards are available, shch as X-10, CEBus(Consumer Electronic Bus), Echonet and Homeplug. This thesis studies the Homeplug AV specification developed by the Homeplug powerline Alliance. By employing MATLAB/Simulink, we build up a PLC baseband transmission model and simulation platform. We carry out the Homeplug AV baseband transmission performance in system level on this platform. The Homeplug AV adopts 3072-point FFT which is not the power of two. It will be a challenge to design the 3072-point FFT processor. Here, we use Xilinx System Generator to design and implement the 3072-point FFT processor. The function verification of the implemented 3072-point FFT processor for Homeplug AV system is carried out by simulation.
33

Modelling Chemically Enhanced Primary Settlers Treating Wastewater using Particle Settling Velocity Distribution : Modellering av kemfällning i försedimentering för avloppsvatten, genom att använda distribuering av sedimentationshastigheter för suspenderadepartiklar.

Lundin, Emma January 2014 (has links)
The urban sprawl creates a gap between producers and consumers and the a sustainable circuitof nutrients and energy is difficult to maintain. Many times the waste that is created in urbanareas is not reused and the circuit is lost. In this project, wastewater treatment is looked atwith the view point that resource recovery is possible through energy production and reuse ofnutrients. In order to optimally run each process step at a wastewater treatment plant forimproved resource recovery, more knowledge is needed in order to not disregard the finaleffluent quality. The goal of this project was to develop a model in MATLAB/Simulink for achemically enhanced primary clarifier at a wastewater treatment plant. The potential ofproducing more biogas and reducing the aeration energy needed in the biological treatmentstep was looked at by focusing on describing the settling velocity of suspended solids.Experimental analysis on settling properties for solids was performed on sampled wastewaterentering the primary settler after changing the addition of chemicals prior in the process line.The wastewater samples were homogenized and then rapidly vacuum pumped up in a column.The solids in the column could thereafter settle and was retained in a cup at the bottom. Themass of total suspended solids (TSS) was classified in five different settling velocity classes,each class assigned a characteristic settling velocity. The experimental procedure followed theViCA's protocol (French acronym for Settling Velocity for Wastewater). A settler, much likethe secondary settler in the Benchmark Simulation Model No. 2 (BSM2), a 10 layer nonreactivetank was modeled. The mass balance in each layer of the settler was decided by thevertical solid flux in the tank and built on the characteristic settling velocity gained from theexperiments. Re-circulation of excess sludge from the subsequent steps at the plant showed toeffect the settling properties of the sludge in the primary settler. The components of TSSshowed to have the largest effect on the distribution of settling velocity. The variation in doseof both coagulant and cationic polymer prior the primary settling tank showed to effect theparticle settling distribution somewhat. A first simulation with an applicable dynamic influentscenario was run. Despite any proper calibration the model gave fairly good predictions ofmeasured TSS in the effluent and sludge outtake water. / När urbana områden växer uppstår svårigheter i att bibehålla ett hållbart kretslopp av energioch näringsämnen. Avståndet mellan producent och konsument ökar och många gångeråteranvänds inte det avfall som städerna producerar och det hållbara kretsloppet bryts. Dettaprojekt har fokuserat på resursåteranvändningen i avloppsvattenhanteringen genommöjligheterna som finns i energiproduktion i form av biogas samt återanvändning avnäringsämnen genom slamåterförsel. Mer kunskap behövs inom varje processteg för attoptimalt använda avloppsreningsverk för förbättrad resurs-återvinning så att inte utgåendevattenkvalitet blir lidande. Målet med projektet var att utveckla en modell iMATLAB/Simulink för primärsedimentering med kemisk fällning. Experimentelltanalyserades sedimentationsegenskaperna hos primärslam genom provtagning avavloppsvatten inkommande till försedimenteringen efter tillsatser av fällnings-kemikalier.Proverna homogeniserades och vakuumpumpades sedan snabbt upp i en kolonn. Detpartikulära materialet i kolonnen kunde därefter sedimentera och fångades upp i en kopp ibotten. Den sedimenterade massan av totalt suspenderat material (TSS) klassificerades i femolika sedimenteringshastighetsklasser och varje klass tilldelades en karakteristisksedimentationshastighet Det experimentella förfarandet följde ViCA’s protokoll (franskförkortning för sedimentationshastigheter för avloppsvatten). En modell av ensedimentationstank, ungefär som för sekundär-sedimenteringen i Benchmark SimulationModel No. 2 (BSM2), utvecklades som en 10 lager icke reaktiv tank. Massbalansen i varjelager bestämdes av det vertikala flödet av partiklar och beräknades med de experimentelltframtagna karakteristiska sedimentationshastigheterna. Återcirkulering av överskottsslam frånde efterföljande reningsstegen visade sig ha stor påverkan på slammetssedimentationsegenskaper i försedimenteringen. Typen av TSS-komponenter hade den störstainverkan på fördelningen av sedimentationshastigheter. Variationen i dos av bådefällningskemikalie och katjonspolymer före primär-sedimenteringstanken hade en visspåverkan på fördelningen. En första simulering med ett sannolikt dynamisk inflödesscenariokördes. Utan någon riktig kalibrering av modellen gav den ändå en relativt realistisk prognospå TSS i utgående vatten och i slamuttaget. / I samarbete med forskningsgruppen ModelEAU, Quebec, Kanada
34

Kmitání strojů v průmyslové praxi / Vibration of Production Machines

Hadraba, Petr January 2017 (has links)
The vibration analysis of a production machine is a key factor of its functionality, service life and occupational safety. This work deals with mathematical dynamic modelling and its contribution to the improvement of a mechanical design and mechanism failure prevention. The whole process is presented on the example of a drum cam rotary indexing table and on the example of actuators of multi spindle automatic lathes. The analysis consisted of complex nonlinear models based on basic linear models. It was computed using Matlab, Simulink and MSC ADAMS. Models of these mechanisms were validated with experimental measurements. The results were used for mechanical design improvement and for speed control optimization.
35

Turbo kódy a jejich aplikace / Turbo codes and their applications

Ploštica, Stanislav January 2009 (has links)
This Diploma thesis aims to explain the data coding using turbo codes. These codes belong to the group of error correction codes. We can reach the high efficiency using these codes. The first part describes process of encoding and decoding. There are describes parts of encoder and decoder. Principle of encoding and decoding demonstrate a simple example. The end of this part contains description of two most frequently used decoding algorithms (SOVA and MAP). The second part contains description of computer program that was made for using as teaching aid. This program was created in Matlab GUI. This program enables to browse error correction process step by step. This program contains graphic interface with many options and display results. In the third part is described program created in Matlab Simulink that was implemented into the TMS320C6713 kit and there is description of measuring procedure. For verification of efficiency of turbo codes was measured any parameters. Some of these parameters are: number of decoding iterations, generating polynoms and using of puncturing. The last part contains measured value and result evaluation.
36

Simulace řídicích struktur elektromechanických systémů / Simulation of Electromechanical System Control Structures

Petruška, Ľubomír January 2010 (has links)
Construction of motor models is the main topic of this project. Mathematical characterization of AC machine, permanent magnet synchronous motor, separately-excited DC motor, series-wound DC motor, permanent magnet DC motor, switched reluctance motor is also described. Design of models is based on mathematical description of particular motors. Models are created in Matlab Simulink. Each model is implemented in continuous and also in discrete time variant. Selected models are implemented also on processor from Freescale 56F800E Hybrid Controller family. Each model has individual graphic user interface. Besides motor models, there is description and easy algorithm of Space Vector Modulation. Model of this method is also created. Models are build-up into a library, which can be used for simulations and tests of control structures. Results of models simulations are presented at the end of this project. Simulation of models that are implemented on processor is also made in Matlab Simulink environment and is compared to simulation of models that are implemented directly in Matlab Simulink.
37

Simulace pohonu se synchronním motorem s ověřením na reálném systému / Simulation of the Drive with Synchronous Machine and its Evaluation using a Real System

Tkadlec, Josef January 2013 (has links)
Práce se zabývá modelováním PMSM, jeho parametry a jejich získáváním. Dále je v práci popsán model měniče beroucí v potaz dead-time efekt. Tyto modely jsou implementovány společně s dalšími bloky v prostředí Matlab/Simulink a dohromady tvoří knihovnu pro vektorové řízení motorů FSL_MC_TOOL. Součástí práce je také měření a identifikace parametrů skutečného PMSM. Dále byly vytvořeny příklady simulací, v nichž je použit motor s těmito parametry a vyhodnocena přesnost simulace. Tímto jsou simulace ověřeny na reálném systému.
38

Návrh lineárního oscilačního pohonu s vnějším buzením / Design of linear external excitation drive with oscillative motion

Gärtner, Jan January 2010 (has links)
This thesis deals with design of linear external excitation drive with oscillative motion. In the first part of the work is shown describe types of linear motors. Further is a part of analysis of concrete linear drives from patents database. In the next part of this work is straight design of linear external excitation drive with oscillative motion. The conception in-clude geometric model created with software Solidworks, calculation of forces with software Ansys and dynamic models of mechanical and electrical part of drive with software Mat-lab/Simulink. And is a mentions possibility of controls of this drive too.
39

Návrh elektromagnetického laboratorního vibrátoru / Design of electromagnetic laboratory shaker

Vaněček, Michal January 2011 (has links)
My thesis describes the design of a laboratory electromagnetic vibrator, which will be used for testing of the vibrating microgenerators. In the first part of my thesis is the search of selected laboratory electromagnetic vibration generators. There is also formulated its own proposal and subsequent tuning of the required dimensions and characteristics of the laboratory electromagnetic vibration generator. The tuning of necessary properties and dimensions is formed as modeling and simulating in programms Matlab / Simulink and ANSYS. The conduct of laboratory electromagnetic vibration generator is implemented in MATLAB / Simulink. Design and dimensions of the laboratory electromagnetic vibration generator is made in SolidWorks.
40

Enhanced frequency regulation functionality of grid-connected PV system

Showers, Obu Samson January 2019 (has links)
Thesis (MEng (Electrical Engineering))--Cape Peninsula University of Technology, 2019 / Electric utilities are confronted with challenges like rising fuel costs, aging equipment, increasing energy demand, frequency regulation and the difficulty to integrate renewable energy resources into the grid. The presence of photovoltaic (PV) penetration on the utility grid is also increasing significantly in recent years. With the recent rise in PV penetration and the advancement of the global PV industry, there is an urgent and a necessary need to introduce features in PV systems that will make them respond smartly. However, much of these can be addressed without negatively affecting the total performance and power quality of the grid. Hence, engaging smart Grid technologies, and leveraging the benefits of the distributed nature of PV, new prospects to unearth value can be created. Through the implementation of progressive energy storage techniques, efficient two-way communications, a grid-tied PV system can create significant value, mostly through improved PV contribution in grid support functions like frequency regulation. An enhanced frequency regulation functioning scheme for a grid-connected photovoltaic (PV) system is modelled in MATLAB/Simulink software environment. The system is designed to operate in grid ancillary services precisely, frequency regulation function. The model consists of a Photovoltaic (PV) plant with a battery connected to the grid through a three-phase inverter. A bi-directional DC-DC converter between the grid and the battery system is included. The model has a battery storage system that provide steady and regular active/reactive powers available while the grid transmit specific amounts of power needed for a specific duration. According to the design, either the grid or the PV system depending on the dominant energy situation charges the battery. The battery is designed to discharge only when the grid demands energy from the PV and if the PV system fails to meet the demanded active power or reactive power. The PV system and the battery storage is integrated with the grid with the aid of dc-ac inverter in such a manner that bi-directional flow of active and reactive power is achieved. A 1 MW PV system is connected to the utility grid through a three-phase voltage source inverter system. The grid nominal frequency is set at 50 Hz under normal operation. However, the frequency decreased when the PV was not producing required power hence, the battery responded almost instantaneously and returned the frequency to the nominal frequency. The effectiveness of battery storage system for utility grid frequency regulation was substantiated from the simulation results attained.

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