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Identifikace parametrů asynchronního motoru / Identification of AC induction motor parametersKřížek, Tomáš January 2008 (has links)
This thesis describes and realizes (in program Matlab/Simulink and in the microcontroller Freescale 56F8346) one off-line identification method of AC Induction motor parameters which are necessary to implement the field-oriented control strategy. The identification metod identify leakage inductance, magnetizing inductance and secondary time constants. The presented method is evaluted, advantages and disadvantages of this method are evaluated with reference to their possible use in real-machine. The experimental results and schemes which are presented demonstrate the feasibility methods. The thesis is dividend in seven chapters. Second chapter describes the basic principle and model AC induction motor. Third chapter generally describes identification methods. Fourth, fifth and sixth chapters deal with method which is based on a previous work of the authors [4] and [5].
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Turbokódy a jejich použití ve sdělovacích systémech / Turbocodes and their application in telecommunication systemsTrčka, Tomáš January 2008 (has links)
This Diploma thesis deals with Turbo code problems. The Turbo codes belong to the group of error correction codes, sometimes referred to as forward error correcting (FEC) codes or channel codes. This thesis can be thematically divided into two basic parts. The first part describes turbo code encoder and decoder block diagram with the illustration of two most frequently used iterative decoding algorithms (SOVA and MAP). The end of this part contains best known turbo codes, which are used in present communication systems. The second part pursues simulation results for the turbo codes using Binary Phase Shift Keying (BPSK) over Additive White Gaussian Noise (AWGN) channels. These simulations were created in the MATLAB/SIMULINK computer program. It will be shown here, that there exist many different parameters, greatly affecting turbo codes performance. Some of these parameters are: number of decoding iterations used, the input data frame length, generating polynoms and RSC encoders constraint lengths, properly designed interleaving block, decoding algorithm used, etc.
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Algoritmy pro systémy s technikou adaptivního frekvenčního skákání / Algorithms for adaptive frequency hopping spread spectrum systemsZunt, Tomáš January 2009 (has links)
This master's thesis deal the system, which use the Frequency Hopping (FH). Is explained principle those techniques and her benefits and disadvantages. Follows description techniques Adaptive Frequency Hopping (AFH) that used the Bluetooth. Follows description other method for setup hopset such as Dynamic Frequency Hopping (DFH), which used standards 802.22. 22. Is an emerging standard for Wireless Regional Area Networks (WRAN) operating on a license-exempt and non-interference basis in the spectrum allocated to TV broadcast services (between 47–910 MHz). Other method introduces the Adaptive Frequency Rolling (AFR), a particular instance of frequency hopping (FH) that enables the collocated WPANs to cooperate and avoid the self-interference. The AFR uses as input solely the observed packet error rate (PER) and it does not require any exchange of information among the collocated WPANs. The effect of the FR over a longer time interval is that the WPANs use the complete set of disposable channels in an implicit time-division and cooperative manner. Last method described in this Thesis is Dynamic Adaptive Frequency Hopping (DAFH). The basic strategy applied in DAFH is a binary search for a hopset that offers smaller PER. The set of admissible hopsets depends on the total number of available channels and the maximal level of binary divisions. Practical part of the master's thesis describes proposal model AFH, with usage of Matlab Simulink programme. In thesis are described function each blocks a their setting. Simulation parameters can change in simple graphic interface. The model is able to simulate influence of static and dynamic interference in transmission band of two communicating devices.
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Řízení stroje s PM v d-q osách při použití Matlab/Simulink / Control of salient PM machine using d-q frame machine model and Matlab SimulinkDušek, Jiří January 2010 (has links)
Tato práce se zabývá synchronním motorem s permanentními magnety na rotoru (PMSM), jeho modelováním a návrhu regulační struktury. V práci jsou uvedeny způsoby a výhody použití permanentních magnetů v elektrických motorech. Dále se práce zabývá transformací třífázové soustavy do dq0. Pomocí Parkovy transformace jsou v práci odvozeny rovnice stroje v dq0 souřadnicovém systému a vytvořeny náhradní schémata stroje v dq osách. Rovnice i schémata zahrnují jak ztráty v mědi, tak ztráty v železe. Náhradní schémata jsou popsány elektrickými a mechanickými rovnicemi a následně překresleny do grafické podoby v programu Matlab Simulink. Vytvořeny jsou dva modely PMSM, jeden s uvažováním ztrát v železe a druhý bez těchto ztrát. Pro oba dva modely je zde popsán postup návrhu regulátorů proudu a otáček. Pro model, u kterého jsou uvažovány ztráty v železe je navíc použito více druhů řídicích strategií a tyto strategie jsou mezi sebou navzájem porovnány.
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Aplikace fuzzy logiky při hodnocení dodavatelů firmy / The Application of Fuzzy Logic for Rating of Suppliers for the FirmLujková, Lenka January 2009 (has links)
This thesis engages in subject matter application of fuzzy logic for rating of suppliers of the firm. This thesis analyses and evaluates competing firms offering to windows exchange and roofing exchange. This thesis can help municipal office in Vážany by decision making, which firm choose.
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Steering of the second front axle in Volvo trucksAsplund, Martin, Landin, Robin January 2020 (has links)
Every few years, modern heavy-duty vehicles get redesigned and can carry more cargo than previously known. Increasing the amount of cargo means increasing the weight, which then leads to more pressure on the engineers to design improved vehicle frames and axles to distribute this load. A recent addition is a second front axle. This axle has been steered with a mechanical link since its introduction, but due to recent law changes, the possibility to steer this axle with an electro-hydraulic system is now available. The purpose of the project is just that, to create an electro-hydraulic steering system, it can be known as steer-by-wire (SBW). Through meetings with lead engineers at Volvo GTT, the first draft of some Concepts could be achieved. The Concepts consisted of a CAD design of the steering, complemented by hydraulic steering. By reusing existing parts in the new design, a similar steering capability was achieved. But having a SBW-system that can attach directly to the new axle, that is not restricted to a connection with the first axle enables so many options, and now, the sky is the limit. The weight is reduced, fuel and energy consumption is reduced, but maybe most important of all. The flexibility of this system is increased, enabling options to have independent steering from the first axle and even changing the placement of the axle on the frame itself. A system like this can have a significant impact on the environmental effects of trucks, as it can reduce the number of vehicles on the road. Thanks to the increase in cargo capacity. / Med några års mellanrum får moderna tunga fordon en ny design och kan frakta mer gods än tidigare. Men att öka mängden gods innebär att öka vikten, vilket leder till mer tryck på ingenjörerna för att designa förbättrade fordonsramar och axlar för att fördela denna last bättre. Nyligen har en andra framaxel lagts till. Denna axel har styrts med en mekanisk länk sedan den infördes, men tack vare de senaste lagändringarna finns nu möjligheten att styra denna axel med ett elektro-hydrauliskt system. Syftet med projektet är just det, att skapa ett elektro-hydrauliskt styrsystem, kan även kallas steer-by-wire (SBW). Genom möten med ingenjörer på Volvo GTT kunde det första utkastet till några koncept uppnås. Koncepten bestod av en CAD-konstruktion av styrningen, kompletterad med en hydraulisk styrning. Genom att återanvända befintliga delar i den nya designen uppnåddes en liknande styrfunktion. Men att ha ett SBW-system som kan kopplas direkt till den nya axeln, det är inte längre begränsat med en anslutning till den första axeln, nu sätter bara fantasin gränserna. Vikten minskas, bränsle- och energiförbrukning minskas, men kanske viktigast av allt. Flexibiliteten i detta system ökar, vilket gör det möjligt att ha oberoende styrning från den första axeln och till och med ändra axelns placering på själva ramen. Ett system som det här kan ha en stor inverkan på miljöeffekterna av lastbilar, eftersom det kan minska antalet fordon på vägen. Tack vare den ökade mängden dom nu kan frakta.
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Identification d’un modèle de mesure au sol du diagramme de rayonnement des antennes installées sur aéronefs / Measurements of on-board antenna radiation patterns on the groundDiakite, Cheick 14 March 2018 (has links)
La détermination du diagramme de rayonnement d’une antenne installée sur un porteur est indispensable pour la validation des systèmes RF auxquels sont associées ces antennes. Lorsque l’antenne est placée sur le porteur, la structure rayonnante est formée par l’antenne et le porteur. Le diagramme doit être déterminé à grande distance de la source dans la zone de champ lointain. Suivant la fréquence de travail et la taille de la source rayonnante, cette distance peut être grande. Elle est par exemple de l’ordre 85m lorsque l’on cherche à caractériser à 88MHz une source rayonnante de dimension maximale 12m. Actuellement, cette distance de champ lointain, est obtenue lors des essais en vol au cours desquels l’aéronef est à 80km de la station sol relevant le diagramme. Cette méthode de caractérisation n’est pas tenable à long terme, en raison de son coût et des temps de mesure. C’est pourquoi Airbus Helicopter veut mettre en œuvre une mesure au sol mais ce dernier perturbe grandement le rayonnement. La méthode de caractérisation retenue permet d’effectuer les mesures au sol dans un espace réduit et permet de s’affranchir de l’influence du sol. La méthode retenue repose sur la caractérisation en champ proche dans une géométrie cylindrique, associée à une technique de correction de diagramme de rayonnement basée sur la décomposition de modes. La mesure champ proche requiert l’acquisition des données de champ proche sur une surface cylindrique, puis un algorithme de transformation développé en environnent MATLAB effectue le passage en champ lointain. Le champ lointain est décomposé en modes cylindriques, puis un filtrage modal est appliqué pour s’affranchir de l’influence du sol. / Aircraft antennas radiation pattern must be measured before radiofrequency systems deployment. When an antenna is on the aircraft, radiating structure is not only antenna element but it’s the set antenna and aircraft. Radiation pattern have to be determined at great distance from the radiating structure. This distance is located in area called far field area depending on the frequency of operation and the maximal size of the aircraft. For example, to measure an antenna on an aircraft of 12 m of long at 88 MHz; the far field area is at 85m.To get this distance, flight measurement is performed. During flight test, radiation pattern is determined by a ground station which is at 80 km of the aircraft. This method is very expensive and takes much time and causes serious delays on aircraft delivery. For these reasons Airbus Helicopters explores new innovative solution, like as radiation pattern measurement on the ground. The last one disturbs the radiation pattern. The proposed method allows to perform measurement in compact volume and cancel out the ground influence. Proposed solution is based on cylindrical near field measurement, and cylindrical modes decomposition. Near field data are scanned on cylinder surface, then an algorithm developed on MATLAB environment do near field to far field transformation. Cylindrical modes decomposition and modal filtering rid of ground reflections. Proposed solution has been validated numerically through comparison with electromagnetic simulator software results. Antenna measurement range in the laboratory has served to validate experimentally the proposed solution on a prototype in scale size.
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Modellbasierte Auslegung des Antriebsstrangs eines NT-PEM-Brennstoffzellen-DemonstratorfahrzeugsLöser, Rico, Wiener, Patrick, Pierer, Alexander, Hoffmann, Michael 27 May 2022 (has links)
Diese Arbeit setzt sich mit der Gesamtheit des Antriebsstrangs vom Brennstoffzellen-Modul bis zum Rad auseinander. Hierfür wird das Verhalten der Niedertemperatur-Polymerelektrolyt-Brennstoffzelle als Einzelzelle und zusammengeschalten als Stack mithilfe eines vereinfachten Greybox-Modells in MATLAB/Simulink® beschrieben. Das Modell, welches zudem an ein idealisiertes aber aussagekräftiges Antriebsstrangmodell gekoppelt ist, erlaubt die Auslegung der Antriebskomponenten für konkrete Betriebsszenarien unter Variation der zu- und abgeführten Medien sowie der Zustandsgrößen Temperatur und Druck. Simulierte Drehmomentverläufe im berechneten Motorkennfeld mit effektivem Arbeitspunkt, Zwischenkreisspannungen und auftretende Verluste in den elektrischen Komponenten bieten die Grundlage, um bereits in der Entwicklungsphase das Zusammenwirken der Antriebskomponenten abzuschätzen und den Antriebsstrang für ein Demonstratorfahrzeug auslegen zu können. / This work addresses the entirety of the powertrain from the fuel cell module to the wheel. For this purpose, the behaviour of the low-temperature polymer electrolyte fuel cell as a single cell and assembled as a stack is described using a simplified greybox model in MATLAB/Simulink®. The model, which is also coupled to an idealized but conclusive powertrain model, allows the design of the powertrain components by varying the media supplied and discharged as well as the state variables temperature and pressure. Simulated torque progressions in the calculated engine characteristics with the effective operating point, DC link voltages and losses occurring in the electrical components provide the basis for estimating the interaction of the powertrain components in the development phase and for dimensioning the powertrain for a demonstrator vehicle.
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Automatic Probing System for PCB : Analysis of an automatic probing system for design verification of printed circuit boardsAalto, Alve, Jafari, Ali January 2015 (has links)
The purpose of this thesis is to conduct an analysis of whether the printed circuit boards from Ericsson can be tested using an automatic probing system or what changes in the design are required, to be a viable solution. The main instrument used for analyzing the printed circuit board was an oscilloscope. The oscilloscope was used to get the raw data for plotting the difference between the theoretical and actual signals. Connected to the oscilloscope was a 600A-AT probe from LeCroy. The programs used for interpreting the raw data extracted from the oscilloscope included Python, Matlab and Excel. For simulations on how an extra via in the signal path would affect the end results we used HFSS and ADS. The results were extracted into different Excel sheets to get an easier overview of the results. The results showed that the design of a board must almost become completely rebuilt for the changes, and it is therefore better to implement in a new circuit board rather than in an already existing one. Some of the components have to either be smaller or placed on one side of the board, where they cannot be in the way of the probe. The size of the board will become larger since the rules of via placements will be limited compared to before. The most time demanding part was the simulations of the extra via in the signal path, and the results showed that if a single-ended signal is below two gigahertz the placing of the via does not make a big difference, but if the signal has a higher frequency the placement is mostly dependent on the type of the signal. The optimal placement is generally around four millimeters away from the receiving end. / Målet med detta examensarbete är att göra en analys av huruvida Ericssons kretskort kan testas med hjälp av ett automatiskt probe system eller om det kräver stora förändringar i designdelen av kretskorten och om, vad för förändringar det i sådant fall kan vara. Till hjälp att analysera kretskorten har vi haft oscilloskop för att få ut rådata om skillnaderna mellan de teoretiska och verkliga signalerna. För att kunna tyda oscilloskopets samplade signaler har olika programmeringsspråk som Python, Matlab samt Excel använts. En extra via i signalens väg har även simulerats i HFSS och ADS med olika sorts probar för att se hur signalens beteende påverkas. Resultaten extraherades sedan in i olika Excel ark för att få en lätt överskådlig bild av resultaten. Resultatet vi fick visade att utformningen av ett kretskort med ändringarna skulle vara lättare att göra med en ny design istället för en redan existerande då större delar av kortet skulle behöva göras om. Vissa stora komponenter behöver antingen göras om, hitta mindre men likvärdiga eller sättas på ena sidan av kortet där de inte är i vägen för proben. Kretskorten som kommer använda flygande probesystem kommer antagligen bli lite större då viornas placering är mer begränsade än tidigare. Det mest tidskrävande arbetet var att simulera olika placeringar av en extra via i signalens väg. Detta visade att på en single ended signal under två gigahertz så gör det ingen större skillnad vart i signalens väg som den extra vian placeras. Då en högre frekvens används så är själva signalens karaktär det viktigaste än placeringen av en via, men om man inte vet den exakta karaktären så är fyra millimeter bort från mottagarens sida att rekommendera då närmare placering av viorna gör att signalerna börjar störa varandra.
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Approche cross-layer pour la minimisation d’énergie dans les réseaux de capteurs sans fil / Cross-layer based energy minimization in wireless sensor networksBen Ammar, Amira 16 November 2018 (has links)
Les réseaux de capteurs sans fil (RCSF) sont des réseaux ad hoc généralement constitués d’entités autonomes miniaturisées appelés noeuds capteurs pouvant communiquer entre eux par liaison radio. Les RCSF ont suscité beaucoup d’engouement dans la recherche scientifique en raison notamment des nouveaux problèmes de routage sous forte contrainte de durée de vie du réseau et de faibles capacités des noeuds.Ce type de réseau diffère des réseaux filaires par ses caractéristiques et limitations qui ont motivé le développement d’une nouvelle approche de conception cross-layer ignorant certains paradigmes de l’approche classique permettant l’échange mutuel d’informations même entre couches non adjacentes. Cette approche qui n’est pas encore standardisée, a démontré son intérêt à travers plusieurs travaux visant un meilleur compromis entre consommation d’énergie et une certaine qualité de service.Nos contributions peuvent être classées en deux catégories suivant la stratégie de routage à savoir le routage ad-hoc et le routage suivant la technique de clustering.Dans la première partie, nous proposons une architecture cross-layer, modulaire, adaptable et extensible nommée XL-AODV (cross layer AODV) basée sur l'échange du SNR (Signal-to-Noise-Ratio) entre la couche réseau et la couche physique qui a été modélisée par la distribution K. Nous évaluons sous le simulateur NS2 les performances de notre approche XL-AODV. Une analyse comparative avec AODV, a montré pour différentes configurations de réseaux, l’efficacité de notre proposition en termes de gains énergétiques et de latence de bout en bout.Pour la deuxième partie, nous proposons une première approche XL-LEACH qui constitue une amélioration de la version originale de LEACH, en l'adaptant aux réseaux de capteurs denses et à grande échelle tout en tenant compte des caractéristiques de la couche physique modélisée par la distribution K. Dans une troisième partie, nous introduisons une amélioration de XL-LEACH par l'approche dite, XL-CLEACH (XL Cooperative LEACH) en intégrant la communication coopérative au niveau MAC. Nous avons prouvé par une étude analytique qui a été validée par les simulations, le gain apporté en termes de consommation d’énergie, de la durée de vie du réseau et du TES (Taux d'Erreur Symbol). Les architectures XL-LEACH et XL-CLEACH ont été implémentées sous MATLAB. / Wireless sensor networks (WSN) can be defined as an ad hoc network consisting of miniaturized autonomous entities, called sensor nodes which communicate with each other over a radio link. WSNs is a research topic which has gained a lot of interest due, in particular, to new routing problems under low node capacity and high network lifetime constraints.WSNs differ from wired networks in their characteristics and limitations which have motivated the development of a new cross-layer design that ignores certain paradigms of the classical approach allowing the mutual exchange of information even between non-adjacent layers. This approach, which is not yet standardized, has gained a lot of attention through several works aiming to energy consumption minimization under a required QoS (Quality of Service).In this thesis, our contributions can be classified are twofold according to the considered routing strategy namely the ad-hoc routing and clustering based routing.In the first part, we propose a new adaptable and extensible cross-layer design called XL-AODV (Cross Layer AODV) based on the exchange of the SNR (Signal-to-Noise-Ratio) between the network and the physical layer which has been modelled by the K distribution.We evaluate under the NS2 simulator, the performance of XL-AODV. A comparative analysis with AODV, showed for different network configurations, the efficiency of our proposition in terms of energy saving and end-to-end latency.In the second part, we propose an XL-LEACH approach which is an improvement of the original version of LEACH by its adapting to dense and large scale sensor networks. We have also taken into account the characteristics of the physical layer modelled by the K distribution.In a third part, XL-CLEACH (XL Cooperative LEACH) approach is introduced to improve XL-LEACH by integrating the cooperative communication at the MAC layer.We have proved through an analytical study and validated by simulations, the gain in terms of energy consumption, network lifetime and SER (Symbol Error Rate). The XL-LEACH and XL-CLEACH architecture were implemented under MATLAB.
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