Techn. Universiẗat, Diss., 2004--Berlin.

University, Diss., 1999--Saarbrücken.

No description available.

Architectural research for Field-Programmable Gate Arrays (FPGAs) tends to use an experimental approach. The benchmark circuits are used not only to compare different architectures, but also to ensure that the FPGA is sufficiently flexible to implement the desired variety of circuits. The most common benchmark circuits used for architectural research are circuits from the Microelectronics Center of North Carolina (MCNC). These circuits are small; they occupy less than 3% [5] of the largest available commercial FPGA. Moreover, these circuits are more representative of the glue logic circuits that were targets of early devices. This contrasts with the trend towards implementing Systems on Chip (SoCs) on FPGAs where several functional modules are integrated into a single circuit which is mapped onto one device. In this thesis, we develop a synthetic system-level circuit generator that connects pre-existing circuits in a realistic manner to build large netlists that share the characteristics of real SoC circuits. This generator is based on a survey of contemporary circuit designs from industrial and academic sources. We demonstrate that these system-level circuits scale well and that their post-routing characteristics match the results of large pre-existing benchmarks better than the results of circuits from previous synthetic generators. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

L’objectif de cette thèse est de développer des stratégies de commande non linéaire et robuste afin d’assurer une connexion avec succès des systèmes hydroliens dans un réseau électrique de forte puissance. Il s’agira en plus, d’étudier en simulation et en pratique le comportement dynamique de ses systèmes hydroliens commandés suite à des perturbations sévères. Dans un premier temps, nous nous sommes intéressés à la modélisation de tous les éléments de la chaine de production d’énergie hydrolienne, en partant de la marée jusqu’à la génératrice synchrone. Dans un second temps, nous avons proposé trois lois de commande non linéaire ; une pour un système hydrolien mono machine et les deux autres pour deux types de réseau électrique multi-machine. La stabilité de ces lois de commandes est prouvée en utilisant la méthode de Lyapunov et les propriétés spécifiques à la structure variable. La particularité de ces lois de commandes est qu’elles régulent simultanément la tension terminale et la fréquence en agissant uniquement sur l’excitation de la génératrice synchrone. Finalement, nous avons étudié en simulation le comportement dynamique des systèmes hydroliens commandés et les résultats obtenus sous perturbations électrique et mécanique ont montré l’efficacité de la commande proposée par rapport aux commandes CNL et AVR-PSS. Dans un souci de valider pratiquement ces résultats de simulation, la commande non linéaire proposée pour le système hydrolien mono machine est implantée sur un banc d’essai. Les résultats satisfaisants obtenus sous perturbations soutenues sont ensuite comparés à ceux obtenus pratiquement avec les commandes, CNL et AVR-PSS. / This thesis develops nonlinear and robust control strategies in order to ensure a successful connection of marine turbine systems into grid. In addition, it is a question to examine in simulation and practice the dynamic behavior of controlled marine turbine systems under severe perturbations. Firstly, we have modeled all production chain elements of marine turbine system. Secondly, we have proposed three nonlinear control strategies ; one for marine turbine system single machine connected to infinite bus and the both others for two multimachine electrical networks. The developed strategies control stability is proven mathematically by using Lyapunov method and one specific property of variable structure. These strategies control particularity is the two outputs regulation (terminal voltage and frequency) trough a single input (synchronous machine excitation). Finally, simulation results under mechanical and electrical perturbations are presented in order to highlight the robustness qualities of the proposed controllers compared to nonlinear controller CNL and classical AVR-PSS. In view of industrial applications, the proposed control for marine turbine single machine system is implemented on experimental bench. The obtained practical results under hard perturbations are very satisfactory. These results are used to realize a comparative study between the proposed control, the CNL and the AVR-PSS.

The purpose of this study has been to design a prototype accelerating tube, to determine the correct point shape and spacing needed to produce corona current along the tube for the case of negative-point-to-positive-plane discharge, and to study the voltage-gradient characteristics of short sections of the tube when they were evacuated to a low internal pressure.

Information in the form of online multimedia, bank accounts, or password usage for diverse applications needs some form of security. the core feature of many security systems is the generation of true random or pseudorandom numbers. Hence reliable generators of such numbers are indispensable. the fundamental hurdle is that digital computers cannot generate truly random numbers because the states and transitions of digital systems are well understood and predictable. Nothing in a digital computer happens truly randomly. Digital computers are sequential machines that perform a current state and move to the next state in a deterministic fashion. to generate any secure hash or encrypted word a random number is needed. But since computers are not random, random sequences are commonly used. Random sequences are algorithms that generate a pattern of values that appear to be random but after some time start repeating. This thesis implements a digital random number generator using MATLAB, FGPA prototyping, and custom silicon design. This random number generator is able to use a truly random CMOS source to generate the random number. Statistical benchmarks are used to test the results and to show that the design works. Thus the proposed random number generator will be useful for online encryption and security.

Information in the form of online multimedia, bank accounts, or password usage for diverse applications needs some form of security. the core feature of many security systems is the generation of true random or pseudorandom numbers. Hence reliable generators of such numbers are indispensable. the fundamental hurdle is that digital computers cannot generate truly random numbers because the states and transitions of digital systems are well understood and predictable. Nothing in a digital computer happens truly randomly. Digital computers are sequential machines that perform a current state and move to the next state in a deterministic fashion. to generate any secure hash or encrypted word a random number is needed. But since computers are not random, random sequences are commonly used. Random sequences are algorithms that generate a pattern of values that appear to be random but after some time start repeating. This thesis implements a digital random number generator using MATLAB, FGPA prototyping, and custom silicon design. This random number generator is able to use a truly random CMOS source to generate the random number. Statistical benchmarks are used to test the results and to show that the design works. Thus the proposed random number generator will be useful for online encryption and security.

The rise in popularity of renewable energy solutions, in particular wind energy systems, has resulted in a greater demand for low-speed direct-drive machines. The Vernier machine has inherent properties such as high torque density, sinusoidal induced voltages and low torque ripple which makes it suitable for low-speed direct-drive wind applications. Additionally, its mechanical structure is as simple as a conventional permanent magnet (PM) machine, whilst eliminating the need for a mechanical gearbox. The research problem addressed by this dissertation relates to the assessment of the Vernier permanent magnet (VPM) machine topology for direct-drive wind applications. It aims to outline a sizing, detailed design and analysis approach for a three-phase VPM wind generator. Furthermore, a comparative study is conducted using two different rotor types and two different stator types, namely; spoke-type and surface-mounted and fractional slot and integral slot respectively. Vernier theory is used to size the designs after which 2D Finite Element Analysis (FEA) simulations are used to analyse and validate the designs. The main outcome of the comparative study is an assessment of the suitability of four topologies for the direct-drive wind application. The design is assessed on parameters which are critical for wind turbine functionality; namely efficiency, torque ripple, torque density and material consumption. The most suitable of the topologies is selected for prototyping. The rotor is made more robust by adding structural features which mechanically secure laminations and PMs to the shaft. The FEA analysis of the prototype showed favourable performance characteristics, albeit with a small cost in power density. The prototype was -thus manufactured with further mechanical reinforcements made to the bearing system. Experimental results reveal the presence of a defect in the windings. Parameters which are dependent on the winding design are much lower than the analytical and FEA values. These parameters include resistance, inductance, and back-EMF. Further work should look into determining the root cause of the prototype defects.

This work deals with calculation and design of synchronous salient pole generator and then the transformation from this machine into so-called hybrid synchronous machine is described. This diploma thesis is done for company Siemens Electric Machines s.r.o. in Drásov. This company provided their design of synchronous salient pole generator. The model of this generator was created in programs RMxprt and Maxwell 2D. Suggestions and models were compared, and their calculated parameters were evaluated. The created model was upgraded to so-called hybrid synchronous generator. Permanent magnets were added in the created model and influence of these additional magnets is going to be analyzed. Tasks of the work are described in more details. in the introduction. The topic of synchronous generator and hybrid synchronous generator in general is described in the theoretical part. The next part of work deals with the design of salient pole generator. In the other part of the work calculation and design of the generator model are described in Ansys program. Furthermore there are some results from program compared with the results from company. Some model parts and other graphic outputs from Ansys program are shown. After that the creation of hybrid synchronous generator is described and created models of hybrid synchronous generators are compared and evaluated.