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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

Supervisory Hybrid Control of a Wind Energy Conversion and Battery Storage System

Khan, Muhammad Shahid 31 July 2008 (has links)
This thesis presents a supervisory hybrid controller for the automatic operation and control of a wind energy conversion and battery storage system. The supervisory hybrid control scheme is based on a radically different approach of modeling and control design, proposed for the subject wind energy conversion and battery storage system. The wind energy conversion unit is composed of a 360kW horizontal axis wind turbine mechanically coupled to an induction generator through a gearbox. The assembly is electrically interfaced to the dc bus through a thyristor-controlled rectifier to enable variable speed operation of the unit. Static capacitor banks have been used to meet reactive power requirements of the unit. A battery storage device is connected to the dc bus through a dc-dc converter to support operation of the wind energy conversion unit during islanded conditions. Islanding is assumed to occur when the tiebreaker to the utility feeder is in open position. The wind energy conversion unit and battery storage system is interfaced to the utility grid at the point of common coupling through a 25km long, 13.8kV feeder using a voltage-sourced converter unit. A bank of static (constant impedance) and dynamic (induction motor) loads is connected to the point of common coupling through a step down transformer. A finite hybrid-automata based model of the wind energy conversion and storage system has been proposed that captures the different operating regimes of the system during grid-connected and in islanded operating modes. The hybrid model of the subject system defines allowable operating states and predefines the transition paths between these operating states. A modular control design approach has been adapted in which the wind energy conversion and storage system has been partitioned along the dc bus into three independent system modules. Traditional control schemes using linear proportional-plus-integral compensators have been used for each system module with suitable modifications where necessary in order to achieve the required steady state and transient performance objectives. A supervisory control layer has been used to combine and configure control schemes of the three system modules to suite the requirements of system operation during any one operating state depicted by the hybrid model of the system. Transition management strategies have been devised and implemented through the supervisory control layer to ensure smooth inter-state transitions and bumpless switching among controllers. It has been concluded based on frequency domain linear analysis and time domain electromagnetic transient simulations that the proposed supervisory hybrid controller is capable of operating the wind energy conversion and storage system in both grid-connected and in islanded modes under changing operating conditions including temporary faults on the utility grid.
32

Fault Tolerant Deployment, Search, And Task Cooperative Contol Of Robot/sensor Networks

Akin, Berkant 01 September 2005 (has links) (PDF)
This thesis focuses on developing of a distributed, efficient and fault tolerant multiresolutional architecture for sensor networks. For demonstrative purpose, a powerful simulation environment using 3D environment model has been developed. The robot network is composed of autonomous robots capable of working cooperatively equipped with single typed simple sensor. The developed layered control architecture is hybrid including both subsumption and motor schema control strategies. In this proposed control method, behaviors in different or in same layer are coordinated with an evaluator unit that overcomes the difficulties of subsumption based architectures in terms of behavioral coordination. The final coordination between these layers is achieved cooperatively. We performed many simulation experiments to test robot deployment, search and task execution. It is shown that some important parameters such as target reaching time, energy consumption, and communication range can be optimized if an approximate prior information about the environment is known. Robots executes task based on a task allocation algorithm. Market based auction method is used as a task allocation algorithm with completely different robot fitness evaluation method allowing a distributive problem solving. Six non-linear fitness functions are developed to increase the fairness, and fault tolerance of task allocation. These functions have been tested to represent the successes and failures of robots in a compact form. Performance analyses test results have shown that fairness increases two times more in task allocation when these fitness functions are used, compared to the results existing fitness evaluation methods used in the market based auction algorithms. Moreover, fault tolerance is increased by using fitness functions devoted to failure conditions.
33

Power network in the loop : subsystem testing using a switching amplifier

Goyal, Sachin January 2009 (has links)
“Hardware in the Loop” (HIL) testing is widely used in the automotive industry. The sophisticated electronic control units used for vehicle control are usually tested and evaluated using HIL-simulations. The HIL increases the degree of realistic testing of any system. Moreover, it helps in designing the structure and control of the system under test so that it works effectively in the situations that will be encountered in the system. Due to the size and the complexity of interaction within a power network, most research is based on pure simulation. To validate the performance of physical generator or protection system, most testing is constrained to very simple power network. This research, however, examines a method to test power system hardware within a complex virtual environment using the concept of the HIL. The HIL testing for electronic control units and power systems protection device can be easily performed at signal level. But performance of power systems equipments, such as distributed generation systems can not be evaluated at signal level using HIL testing. The HIL testing for power systems equipments is termed here as ‘Power Network in the Loop’ (PNIL). PNIL testing can only be performed at power level and requires a power amplifier that can amplify the simulation signal to the power level. A power network is divided in two parts. One part represents the Power Network Under Test (PNUT) and the other part represents the rest of the complex network. The complex network is simulated in real time simulator (RTS) while the PNUT is connected to the Voltage Source Converter (VSC) based power amplifier. Two way interaction between the simulator and amplifier is performed using analog to digital (A/D) and digital to analog (D/A) converters. The power amplifier amplifies the current or voltage signal of simulator to the power level and establishes the power level interaction between RTS and PNUT. In the first part of this thesis, design and control of a VSC based power amplifier that can amplify a broadband voltage signal is presented. A new Hybrid Discontinuous Control method is proposed for the amplifier. This amplifier can be used for several power systems applications. In the first part of the thesis, use of this amplifier in DSTATCOM and UPS applications are presented. In the later part of this thesis the solution of network in the loop testing with the help of this amplifier is reported. The experimental setup for PNIL testing is built in the laboratory of Queensland University of Technology and the feasibility of PNIL testing has been evaluated using the experimental studies. In the last section of this thesis a universal load with power regenerative capability is designed. This universal load is used to test the DG system using PNIL concepts. This thesis is composed of published/submitted papers that form the chapters in this dissertation. Each paper has been published or submitted during the period of candidature. Chapter 1 integrates all the papers to provide a coherent view of wide bandwidth switching amplifier and its used in different power systems applications specially for the solution of power systems testing using PNIL.
34

Sistema híbrido, manual e automático para controle de posição e trajetória em máquinas de usinagem. / Manual and automatic, hybrid system for the position and path control in machine tools.

Loer Nércides Franco García 18 December 2007 (has links)
Com o presente projeto se pretende desenvolver um protótipo de máquina de usinagem para atender a fabricação de pequenos lotes (10~20 peças), Esta máquina terá características intermediárias entre as máquinas universal (manual) e de controle numérico (CN); conjugando as vantagens funcionais destas duas: alta eficiência e flexibilidade. A máquina projetada terá uma operação manual (trajetória), e seu posicionamento será servo-assistido. Entenda-se \"desenvolver\" como: a) Propor uma estratégia de usinagem; b) Propor uma configuração de máquina que funcione segundo esta estratégia; c) desenvolver um protótipo e; d) validar a estratégia e a configuração através de testes no protótipo. A estratégia de posicionamento aqui proposta, é baseada em um posicionamento manual, ou seja, o operador define livremente o movimento da ferramenta com relação à peça a se fabricar. Porém, um computador monitora constantemente a posição da ferramenta e não permite a entrada desta numa região, nomeada \"Região Proibida\"; que corresponde ao perfil da peça. A região proibida é definida diretamente a partir de um desenho de CAD, dispensando o uso de alguma ferramenta computacional de geração automática de trajetória de ferramenta. Deste modo, o operador realiza a usinagem de desbaste. O acabamento é realizado automaticamente pelo computador, que faz com que a ferramenta contorne o perfil da peça, uma vez que o operador envia um sinal de partida. Uma possível configuração de máquina para alcançar esta estratégia é apresentada. E consiste de uma mesa XY servo controlada, adaptada a uma furadeira de bancada, onde operador comanda o movimento da mesa mediante um joystick. Através de ensaios de usinagem, o trabalho demonstra a eficácia da estratégia proposta. / Present project aims the development of a machine tool prototype for attend the manufacturing of small lots (10~20 pieces), This machine will have characteristics intermediate between the universal and the numerical control (CN) machines. The desired machine conjugates the functional advantages of both types of machines: high efficiency and flexibility. The machine, thus designed, will have a manual operation (the tool path is defined by the operator), and its positioning will be servoassisted. Here, \"to develop\" includes: a) to propose a machining strategy; b) to propose an arrangement of machine that works according to this strategy; c) to develop a prototype and; d) to validate the strategy and the arrangement through tests with the prototype. The positioning strategy, is based on a manual positioning, i.e., the operator defines freely the motion of the tool with respect to the work piece. However, a computer monitores constantly the tool position, not permitting the entrance of it inside the area, here called \"prohibited region\", corresponding to the profile of the part to be machined. Outside that region, the computer enables operator to move the tool as he wants. The prohibited region is defined directly from a CAD draft, eliminating the necessity of any kind of computer tools for generating automatically the tool path. Thus, the operator executes the rough machining. The finishing path is executed automatically by the computer that makes the tool contour the profile of the part, according to the start-up command given by the operator. In the work, one possible arrangement of machine to achieve this strategy is presented. It consists of servo controlled XY table and adjusted to a bench drill in which, the operator commands the table motion by means a joy-stick. By machining tests, this work shows the efficiency of the proposed strategy.
35

Hybrid position controller for an field-oriented induction motor drive / EstratÃgia hÃbrida aplicada no controle de posiÃÃo de um sistema de acionamento com motor de induÃÃo usando controle de campo orientado

AntÃnio Barbosa de Souza JÃnior 12 September 2014 (has links)
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / This work describes the study and implementation of a hybrid control technique applied to the positioning of the rotor shaft in a three-phase induction motor (IM). The machine has been modeled using the field oriented control (FOC) strategy. In additional, it is used three controllers to obtain the design of the position loop, each one with different operating characteristics. Initially, two constant gain controllers are associated with the position loop diagram in the FOC technique in order to obtain a fastest response, with disturbance rejection and without overshoot. Therefore, it used a Proportional (P) controller based on Ziegler-Nichols tuning method so that a faster system response is achieved and a predictive control strategy called Generalized Predictive Control (GPC), based on Proportional â Integral controller tuning form, to smooth the overshoot caused by the P controller. Subsequently, seeking a more efficient performance of the position control in the IM, It used a control strategy based on fuzzy logic that takes into account the weighting of P and GPC controllers together. For purposes of validation, simulations and experimental results of the P, GPC and hybrid control strategies are presented. The simulation was set up in Matlab/Simulink and the experimental plant was implemented with a Digital Signal Controller (DSC), manufactured by Texas Instruments TMS320F2812. Analyzing the results, the Proportional demonstrated the fastest reference tracking, among the others techniques, with a settling time of 0.25 seconds, however with overshoot. The GPC controller presented a longer accommodation time, about 2 seconds and without overshoot. The application of the hybrid proposed technique combine the fast tracking reference of the P controller, about 1 second to reach the reference, and without overshoot as in the GPC controller results. Besides, the robust characteristic of both controllers was maintained in the hybridization proposed technique. / Este trabalho descreve o estudo e implementaÃÃo de uma tÃcnica de controle hÃbrida aplicada ao posicionamento do eixo de um motor de induÃÃo trifÃsico (MIT). O motor de induÃÃo foi modelado usando-se a estratÃgia de controle de campo orientado a fim de projetar para a malha de posiÃÃo trÃs controladores, cada um com diferentes caracterÃsticas de operaÃÃo. Neste caso, incorporou-se inicialmente à malha de posiÃÃo da estratÃgia de controle de campo orientado a aÃÃo de dois controladores de ganho constante com o objetivo de posicionar o eixo de forma rÃpida, com pouco sobressinal e com rejeiÃÃo à perturbaÃÃo. Desta forma, utilizou-se um controlador Proporcional (P) com sintonia baseada em Ziegler-Nichols de modo a se obter uma caracterÃstica mais rÃpida do sistema e, uma estratÃgia de controle preditivo denominada de GPC (Generalized Predictive Control) com o objetivo de suavizar a aÃÃo do controlador P em termos de elevado sobressinal considerando a sintonia do controlador GPC baseada em um controlador Proporcional-Integral (PI). Posteriormente, para se obter um desempenho mais eficiente do controle de posiÃÃo do MIT, utilizou-se uma estratÃgia de controle baseada em lÃgica fuzzy de modo a se levar em conta a ponderaÃÃo dos controladores P e GPC, conjuntamente. Para fins de validaÃÃo sÃo apresentados resultados da aplicaÃÃo das estratÃgias de controle P, GPC e hÃbrida no controle de posiÃÃo do MIT a partir de simulaÃÃes em ambiente Matlab/Simulink e atravÃs da implementaÃÃo do sistema de controle de posiÃÃo utilizando-se um processador digital de sinais, o DSP TMS320F2812 fabricado pela Texas Instruments. A partir dos resultados encontrados, o Proporcional demonstrou um rÃpido seguimento de referÃncia, dentre as tÃcnicas utilizadas, com tempo de acomodaÃÃo experimental de 0,25 segundos, porÃm com sobressinal. O controlador GPC apresentou um tempo de acomodaÃÃo maior, cerca de 2 segundos e sem sobressinal. A aplicaÃÃo da tÃcnica hÃbrida proposta conseguiu combinar o rÃpido seguimento de referÃncia do Proporcional, levando cerca de 1 segundo para alcanÃar a referÃncia, e sem sobressinal como o controlador GPC. AlÃm do que, como os controladores possuem uma caracterÃstica robusta tambÃm se garantiu essa propriedade para o hibridismo proposto.
36

Contribution à la modélisation et au contrôle de trajectoire de Trackers photovoltaïques à haute concentration (HCPV) / Contribution to the modeling and control of high concentrated Photovoltaic tracker (hcpv)

Sahnoun, Mohamed Aymen 18 December 2015 (has links)
Dans une optique de maximisation de la production et de réduction des coûts d’installation, de maintenance et d’entretien des trackers solaires, qui permettent d’orienter les modules photovoltaïques à haute concentration (HCPV), ces travaux de thèse se focalisent sur l’amélioration de la précision et la réduction du coût de la stratégie de génération de la trajectoire du tracker. Dans un premier temps, un simulateur de tracker HCPV est développé offrant une étude de l’influence de la performance du suivi du soleil sur la production des modules HCPV, permettant ainsi une étude et une comparaison des stratégies de génération de trajectoires. Le simulateur est basé sur un modèle comportemental de module HCPV monté sur tracker permettant de prédire la puissance maximale du module HCPV en fonction de l’erreur de position du tracker face au soleil, de l’ensoleillement direct et de la température. Une première stratégie de commande dite de référence a été implémentée sur ce simulateur. C’est une commande hybride qui repose sur un viseur solaire pour corriger l’erreur de poursuite par un calcul astronomique. Ensuite, afin d’améliorer les performances et de réduire les coûts de cette stratégie, une nouvelle approche sans capteur est développée en se basant sur une méthode d’optimisation du gradient de puissance pour la génération de la trajectoire du tracker. Une étude complémentaire est également exposée afin de mettre en évidence des algorithmes de recherche de la puissance maximale (MPPT) pouvant offrir des temps de réponse suffisamment rapides pour ne pas affecter la qualité de l’évaluation du gradient de puissance. Dans ce contexte, une commande MPPT P&O améliorée par un réseau de neurones à complexité réduite est proposée, assurant un compromis entre précision, simplicité et rapidité / This work focuses on improving the accuracy and on reducing the cost of the tracker generating trajectory strategy, in order to maximize the production and to reduce the installation and the maintenance cost of a solar tracker orienting high concentrated photovoltaic modules (HCPV). Initially, we propose a behavioral modeling of the HCPV module mounted on a dual axis tracker in order to study the influence of the tracking performance on the module power production. Then, this simulator can be used to test control strategies and to compare their performance. Firstly, a classical control strategy is implemented in the simulator. It is based on a hybrid control operating an astronomical calculation to follow the sun path, and a sun sensor to correct the tracking error. A sensorless strategy is proposed in this work to reduce the cost of the HCPV tracker control. This strategy is based on a gradient optimization algorithm to generate the tracker trajectory and to catch the sun path. Tested on the simulator, this strategy presents the same accuracy as the classical strategy while being less costly. The last study proposed in this thesis work concerns maximum power point tracking (MPPT) algorithms, in order to respond to a given problem relating to the practical implementation of gradient algorithm. In this context, we propose an original optimization of the P&O MPPT control with a neural network algorithm leading to a significant reduction of the computational cost required to train it. This approach, which is ensuring a good compromise between accuracy and complexity is sufficiently fast to not affect the quality of the evaluation of the gradient.
37

[en] HYBRID CONTROL FOR REDUCING BUILDING VIBRATIONS / [pt] CONTROLE HÍBRIDO PARA ATENUAÇÃO DE VIBRAÇÕES EM EDIFÍCIOS

SUZANA MOREIRA AVILA BENEVELI 01 November 2002 (has links)
[pt] No presente trabalho estuda-se a aplicação do controle estrutural na proteção de estruturas submetidas a carregamentos dinâmicos contra níveis de vibração indesejáveis que possam causar desconforto e, até mesmo, comprometer a segurança e integridade da edificação. Os três tipos de controle estrutural, passivo, ativo e híbrido, são analisados de forma a evidenciar as vantagens do uso do controle híbrido. O mecanismo de controle utilizado é o denominado amortecedor de massa sintonizado (AMS), devido à sua vasta aplicação na Engenharia Civil, tendo uma grande quantidade sido instalada em edifícios, pontes e chaminés industriais para controle de vibrações causadas pelo vento. Verifica-se a influência da não- linearidade da rigidez do AMS no comportamento do sistema principal. A utilização de amortecedores de massa sintonizados múltiplos é também estudada como uma forma de vencer certas limitações quanto à robustez deste tipo de sistema e melhorar sua performance. Analisa-se por fim o comportamento e eficiência do amortecedor de massa híbrido (AMH), em relação ao AMS passivo. Para cálculo da força de controle são utilizados os seguintes algoritmos: controle ótimo linear clássico, controle ótimo instantâneo e controle ótimo não-linear. Uma estratégia para definição das matrizes de ponderação, utilizadas no algoritmo de controle ótimo instantâneo, que minimizem a amplitude da resposta harmônica permanente é apresentada. Exemplos numéricos são apresentados ao longo de todo o trabalho. Verifica-se que a utilização do controle híbrido é mais eficiente que os controles passivo e ativo isolados, requerendo forças de magnitude inferiores, o que reduz bastante o custo deste tipo de sistema. O sistema de controle híbrido se mostrou eficiente na redução de vibrações causadas por carregamentos cujas freqüências eram diversas das consideradas no projeto do sistema de controle passivo. Verificou-se, ainda que o mesmo se comportou de forma satisfatória no caso de discrepância na freqüência natural da estrutura. / [en] In this work the use of structural control is studied to protect dynamically loaded building structures against undesirable vibration levels, which can cause human discomfort and, even more, compromise the building safety and integrity. The three types of structural control, passive, ative and hybrid, are analysed to show the advantages of hybrid control in reducing undesirable vibration levels. The chosen control mechanism is the so called tuned mass damper (TMD), due to its large application in Civil Engineering, having a great number of these devices been installed in buildings, bridges and industrial chimneys to control structural vibrations induced by wind loads. It is also verified the influence of TMD non linear stiffness on the main system behaviour. The use of multiple tuned mass dampers is studied as a possible way of improving the TMD robustness and performance. The hybrid mass damper (HMD) behaviour and efficiency comparing to the passive mass damper is analysed in detail. To calculate the control force the following control algorithms are used: classical optimum linear control, instantaneous optimum control and non-linear optimum control. A strategy to define the weighting matrices used in the instantaneous optimum control algorithm that minimizes the harmonic response amplitude is presented. Several numerical examples are presented aalong the work. The results show that the hybrid control is more efficient that the passive or active control used separately, requiring smaller forces reducing in this way the cost of the control system. The hybrid control system showed to be more efficient in reducing vibrations caused by loadings which had different frequencies from that considered on the passive control design. Moreover it was shown that hybrid control has a satisfactory perfomance when discrepancies in natural frequency occur.
38

Porovnání koncepcí hybridního pohonu v režimu denního dojíždění do práce / Comparison of Hybrid Powertrain Topologies in Daily Commuting Regime

Ušiak, Michal January 2020 (has links)
The master’s thesis deals with modelling of various architectures of hybrid powertrains for three vehicle sizes in GT-SUITE and compares them in daily commuting operating mode. On top of making of the hybrid vehicle simulation models, control algorithms had to be created to manage the energy split between the internal combustion engine and the electric motor for each of the architectures. Routes to work and back were logged using the GPS and postprocessed to obtain the speed and the road grade profiles. Resulting data was used as an input in simulations of daily commuting. To compare all hybrid powertrain architectures, fuel economy and electricity consumption were evaluated for WLTP and daily commuting operating modes. Finally, the environmental impact of each topology was assessed based on an estimation of corresponding well-to-wheel emissions.
39

High Performance Drivetrains for Powerful Mobile Machines

Schumacher, Andreas, Rahmfeld, Robert, Laffrenzen, Heiko January 2016 (has links)
This paper discusses the current and future drivetrain perspectives of powerful mobile machines, especially in regards to TCO and drive performance. For the TCO-impact, the power losses of the components plays a big role and, if they are designed for efficiency, they have a significant and measurable influence. From the braking function point of view, this paper demonstrates not only the advantages of a valve-based over a control algorithm based solution, but also its innovative development directions towards a more sophisticated engine speed controller with optimized heat conversion into the oil. Also for the drivetrain subsystems, innovative components are discussed, like the hybrid control, combining the benefits of a non-feedback and a displacement control in one single assembly, or the variable charge system for further reduced energy consumption of the overall drivetrain.
40

Hybrid PEM fuel cell systems

Gößling, Sönke, Smyrek, Felix, Bahr, Matthias 27 May 2022 (has links)
Nowadays, PEM fuel cell systems for passenger cars are always realized as hybrid systems. If the architecture of a hybrid system is given, then the dimensioning of the fuel cell and battery subsystems is crucial in terms of costs, dynamics, and driving behavior in general. In order to analyze these dependencies correctly, the ZBT fuel cell model was integrated into a fuel cell system and a full vehicle simulation. The subject of the investigation is the interaction of different drive cycles, which in part are very different, with differently dimensioned sub models for the fuel cell system and the battery. The ZBT fuel cell model is integrated into the simulation environment AVL CRUISE™ M for the fuel cell system and the vehicle. An analysis is presented that compares the different drive cycles and system dimensions and provides specific recommendations for different use cases.

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