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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.
21

Análise de turbinas eólicas conectadas ao sistema elétrico equipadas com geradores síncronos a ímãs permanentes. / Analysis of wind turbines with permanent magnet generator in the power system.

Mauricio Andres Paez Prieto 17 July 2014 (has links)
Este trabalho de mestrado está relacionado com a análise do comportamento dinâmico de turbinas eólicas equipadas com gerador síncrono com excitação a ímãs permanentes operando durante contingências na rede elétrica e com variação na velocidade do vento. Tal configuração tem muitas vantagens quando comparada com a configuração atualmente utilizada pelos principais fabricantes de turbinas eólicas de grande porte. A principal delas é devido ao fato de não utilizar caixas de engrenagens. Porém, o impacto na rede elétrica com a conexão de tal configuração deve ser minimizado melhorando as condições operativas no ponto de conexão da fazenda eólica. Desta forma, o projeto em questão visa investigar formas de diminuir os impactos negativos causados e melhorar a estabilidade do sistema, principalmente, no ponto de conexão à rede elétrica Portanto, o projeto de pesquisa deste mestrado está relacionado ao desenvolvimento de modelos computacionais que representem tal tecnologia, considerando os principais componentes e controles utilizando o software de simulação PSCAD. Também são incluídos novos métodos de controle e elementos adicionais que melhoram a confiabilidade e o nível de penetração de parques eólicos com geradores a ímãs permanentes. Ressalta-se que tais modelos não estão disponíveis de forma completa no software citado acima, portanto foram desenvolvidos partindo de modelos genéricos existentes. Todas as partes do modelo foram realizadas com elementos básicos acessíveis em qualquer programa de simulação, de modo que qualquer engenheiro ou pesquisador possa programar este mesmo modelo em qualquer software. Esta dissertação começa com uma breve descrição do modelo desenvolvido, incluindo o modelo aerodinâmico das turbinas eólicas, o controle do conversor do lado do gerador, o controle do conversor do lado da rede e o sistema de proteção do link de corrente contínua. Com o modelo desenvolvido, analisa-se a operação do gerador síncrono a imãs permanentes durante contingências na rede. A aplicação de um sistema avançado de armazenamento de energia e a possibilidade de suporte de frequência à rede elétrica também foram desenvolvidos e analisados. Considerando os resultados obtidos, podemos verificar que a conexão de parques eólicos equipados com geradores síncronos com excitação a ímãs permanentes pode trazer benefícios para a rede elétrica, quando o seu potencial de controle e de operação é utilizado. Mais detalhes podem ser verificados nos capítulos a seguir. / This master\'s project aims to study the behavior of wind turbines with Permanent Magnet Synchronous Generator, operating during contingencies and changes in wind speed. This configuration has many advantages compared with configurations currently used by leading manufacturers of large wind turbines. The main one is due to the fact of use smaller gearboxes or even gearless turbines. However, the impact on the electrical grid connection of this configuration should be minimized by improving the operating conditions at the connection point of the wind farm. Thus, this project aims to investigate ways to reduce the negative impacts and improve the system stability, especially at the grid connection point. This work employs the simulation software PSCAD for developing a computational model of this technology, considering the main components and controls. New control methods and additional features are included, for improving the reliability and the level of penetration of wind farms with permanent magnet generators in the power system. It is noteworthy that such models are not available in the simulation software PSCAD; therefore it was developed from existing generic models. All parts of the model were done with basic elements; as a result any engineer or researcher can program this same model in any software. This work begins with a brief description of the developed model, including: the aerodynamic model of the wind turbines, the control of the generator side converter, the control of the grid side converter and the protection system of the Link-DC. With this model, the operation of the permanent magnet synchronous generator was analyzed during network contingencies. The application of a sophisticated energy storage system for frequency support was also both developed and analyzed. The connection of wind turbines with Permanent Magnet Synchronous Generator has advantages when its potential for control and operation is used. More details can be checked in the following chapters.
22

Modelling, simulation and analysis of low-cost direct torque control of PMSM using hall-effect sensors

Ozturk, Salih Baris 25 April 2007 (has links)
This thesis focuses on the development of a novel Direct Torque Control (DTC) scheme for permanent magnet (PM) synchronous motors (surface and interior types) in the constant torque region with the help of cost-effective hall-effect sensors. This method requires no DC-link sensing, which is a mandatory matter in the conventional DTC drives, therefore it reduces the cost of a conventional DTC of a permanent magnet (PM) synchronous motor and also removes common problems including; resistance change effect, low speed and integration drift. Conventional DTC drives require at least one DC-link voltage sensor (or two on the motor terminals) and two current sensors because of the necessary estimation of position, speed, torque, and stator flux in the stationary reference frame. Unlike the conventional DTC drive, the proposed method uses the rotor reference frame because the rotor position is provided by the three hall-effect sensors and does not require expensive voltage sensors. Moreover, the proposed algorithm takes the acceleration and deceleration of the motor and torque disturbances into account to improve the speed and torque responses. The basic theory of operation for the proposed topology is presented. A mathematical model for the proposed DTC of the PMSM topology is developed. A simulation program written in MATLAB/SIMULINK® is used to verify the basic operation (performance) of the proposed topology. The mathematical model is capable of simulating the steady-state, as well as dynamic response even under heavy load conditions (e.g. transient load torque at ramp up). It is believed that the proposed system offers a reliable and low-cost solution for the emerging market of DTC for PMSM drives. Finally the proposed drive, considering the constant torque region operation, is applied to the agitation part of a laundry washing machine (operating in constant torque region) for speed performance comparison with the current low-cost agitation cycle speed control technique used by washing machine companies around the world.
23

Developing of Robust Integral Velocity-stabilizing Controller for Permanent Magnet Synchronous Motor Driver

Lai, Chun-Ting 14 February 2012 (has links)
The objective of this thesis is to design and implement a velocity-stabilizing driver for permanent magnet synchronous motor. The research presents how to achieve high efficiency in stabilizing overall velocity for a permanent magnet synchronous motor. In order to drive the integral system, there are six steps square-wave starting device, sine-wave driver, estimation of magnetic angle, velocity feedback and current feedback control circuits designed. A test platform is built by Microchip-made dsPIC33FJ128MC804 digital signal processor used as a control core. ¡§Simulink¡¨ simulator is used during the laboratory test. The simulation results are compared with those of experiments in order to verify the achievement of excellent performance of Robust Integral Velocity-stabilizing Controller on Permanent Magnet Synchronous Motor Driver.
24

Design and Implementation of an Inverter Drive for High-Efficiency Compressor used in Air Conditioner

TSENG, WEI-CHIH 11 July 2002 (has links)
Abstract: This paper presents the results of an experimental investigation into the application of inverter-based variable speed drives to positive displacement rotary compressors. Designs and implements a DSP-microprocessor based of an inverter drive for high-efficiency compressor used in air conditioner. We control the compressor with sine PWM and V/F scheme. Permanent magnet synchronous motor has potential for energy saving in general applications on compressor drives. Permanent magnet synchronous motor drives are used for applications like compressors¡Awhere high dynamic performance is not a demand¡Asimple V/F control strategies may be sufficient to obtain the required control performance. For energy saving to find the best control strategy for an inverter drive for high efficiency compressor used in air conditioner.
25

Modelling, simulation and analysis of low-cost direct torque control of PMSM using hall-effect sensors

Ozturk, Salih Baris 25 April 2007 (has links)
This thesis focuses on the development of a novel Direct Torque Control (DTC) scheme for permanent magnet (PM) synchronous motors (surface and interior types) in the constant torque region with the help of cost-effective hall-effect sensors. This method requires no DC-link sensing, which is a mandatory matter in the conventional DTC drives, therefore it reduces the cost of a conventional DTC of a permanent magnet (PM) synchronous motor and also removes common problems including; resistance change effect, low speed and integration drift. Conventional DTC drives require at least one DC-link voltage sensor (or two on the motor terminals) and two current sensors because of the necessary estimation of position, speed, torque, and stator flux in the stationary reference frame. Unlike the conventional DTC drive, the proposed method uses the rotor reference frame because the rotor position is provided by the three hall-effect sensors and does not require expensive voltage sensors. Moreover, the proposed algorithm takes the acceleration and deceleration of the motor and torque disturbances into account to improve the speed and torque responses. The basic theory of operation for the proposed topology is presented. A mathematical model for the proposed DTC of the PMSM topology is developed. A simulation program written in MATLAB/SIMULINK® is used to verify the basic operation (performance) of the proposed topology. The mathematical model is capable of simulating the steady-state, as well as dynamic response even under heavy load conditions (e.g. transient load torque at ramp up). It is believed that the proposed system offers a reliable and low-cost solution for the emerging market of DTC for PMSM drives. Finally the proposed drive, considering the constant torque region operation, is applied to the agitation part of a laundry washing machine (operating in constant torque region) for speed performance comparison with the current low-cost agitation cycle speed control technique used by washing machine companies around the world.
26

External Reactive Power Compensation of Permanent Magnet Synchronous Generator

Singer, Amr 09 June 2011 (has links) (PDF)
This research work focuses on the reactive power compensation of the permanent magnet synchronous generator (PSG) in wind power plants. PSG feeds a fixed voltage dc grid through a rectifier bridge. In variable speed operation, the PSG will be able to build torque only in small speed range. This is due to the fixed magnet of the PSG. External reactive power compensation provides an attractive solution to overcome this problem. Different reactive power compensation configurations were examined. Statics synchronous series compensation and a shunt passive filter were chosen as a compensation method. Simulation and implementation of small wind power plant were performed. The wind power plant consists of the synchronous generator, inverter, rectifier, coupling transformers and shunt passive filter. The experimental results agree to the proposed theory and simulation results. / Der Schwerpunkt meiner Promotion ist die Blindleistungskompensation bei einem permanenterregten Synchrongenerator. Der Synchrongenerator speist das Gleichsspannungsnetz über ein Gleichrichter. In der Drehzahlvariablen Betriebsverhalten können Nachteile auftreten. Die Folge ist, dass bei konstanter Gleichspannung und fester Erregung durch die Permanenterregung nur ein sehr kleiner Drehzahlbereich mit vernünftiger Drehmomentausbeute bedienbar ist. Ein möglicher Ausweg wäre eine variable Kompensationsspannung. Verschiedene Kompensationsverfahren wurden untersucht. Ein Series Active Filter und ein Shunt Passive-Filter wurden als Blindleistungskompensation gewählt. Im Rahmen meiner Dissertation beschäftige ich mich mit dem Aufbau und der Simulation einer Windkraftanlage. Diese besteht aus einem permanenterregten Synchrongenerator, einem Wechselrichrter, einem Gleichrichter, drei Transformatoren und einem passiven Filter. Das Versuchsergebnis zeigt, dass die Theorie mit der Simulation übereinstimmt.
27

Μοντελοποίηση, έλεγχος και προσομοίωση αιολικού συστήματος με σύγχρονη γεννήτρια μόνιμου μαγνήτη / Modelling, control and simulation of a permanent magnet synchronous generator based wind power system

Μπιμπισίδης, Κωνσταντίνος 04 December 2012 (has links)
H αυξανόμενη ανάγκη για στροφή της παραγωγής ηλεκτρικής ενέργειας σε βιώσιμες και ανανεώσιμες πηγές έχει οδηγήσει στη ραγδαία ανάπτυξη της αιολικής ενέργειας και στη διείσδυσή της στην αγορά ενέργειας. Η παρούσα εργασία πραγματεύεται ένα αιολικό σύστημα παραγωγής ενέργειας βασισμένο σε σύγχρονη γεννήτρια μόνιμου μαγνήτη. Η συγκεκριμένη μηχανή αποτελεί τη νέα τάση στην αγορά εξ’ αιτίας των σημαντικών πλεονεκτημάτων που προσφέρει, ιδίως αυτό της δυνατότητας για απουσία κιβωτίου ταχυτήτων που οδηγεί το σύστημα σε αυξημένη απόδοση. Στην εργασία αυτή, θα γίνει μια παρουσίαση των χαρακτηριστικών των σύγχρονων αιολικών συστημάτων, θα γίνει η μοντελοποίηση της σύγχρονης γεννήτριας μόνιμου μαγνήτη και θα αναλυθεί η λογική του ελέγχου που ακολουθείται και στηρίζεται στο διανυσματικό έλεγχο προσανατολισμού σε πεδίο. Τέλος, θα γίνει η παρουσίαση και ο σχολιασμός των αποτελεσμάτων του μοντέλου, που αναπτύχθηκε σε περιβάλλον Matlab/Simulink, με την παράλληλη εξαγωγή συμπερασμάτων για την απόκρισή του. / The ongoing increase in electric power demand and the need for sustainable and renewable energy has led wind energy into high rates of growth and penetration to the energy markets. This thesis deals with a permanent magnet synchronous generator based wind power system. This type of machine has become a trend for the markets, due to its specific benefits and, especially, for the absence of gearbox that leads the whole system to higher efficiency. In this thesis, we will discuss the characteristics of a modern wind power system, then, the permanent magnet synchronous generator will be modelled, and the field oriented vector control strategy will be analyzed. Finally, we will present and discuss the outcome of the model that was built in the Matlab/Simulink programme, and we will come into certain conclusions about its response.
28

Ανάλυση και έλεγχος αιολικού συστήματος παραγωγής ηλεκτρικής ενέργειας με σύγχρονη μηχανή με μόνιμους μαγνήτες

Γκουντρουμάνη, Βάια 14 October 2013 (has links)
Η παρούσα διπλωματική εργασία πραγματεύεται τη μελέτη μιας διάταξης ανεμογεννήτριας με σύγχρονη μηχανή με μόνιμους μαγνήτες η οποία συνδέεται μέσω dc διασύνδεσης με το δίκτυο. Τη dc διασύνδεση τη δημιουργεί ένας dc πυκνωτής και από την πλευρά της μηχανής υπάρχει ένας ac/dc πλήρως ελεγχόμενος ανορθωτής ισχύος ενώ από την πλευρά του δικτύου βρίσκεται ένας dc/ac πλήρως ελεγχόμενος αντιστροφέας ισχύος. Σκοπός της εργασίας είναι αρχικά να μελετήσουμε θεωρητικά το συνολικό σύστημα της ανεμογεννήτριας χρησιμοποιώντας το μετασχηματισμό Park για τη μοντελοποίηση του στο d-q πλαίσιο αναφοράς. Στη συνέχεια προχωρούμε στον υπολογισμό των εξισώσεων στο χώρο κατάστασης και τελικά προτείνουμε ένα σύστημα ελέγχου το οποίο βασίζεται στους PI ελεγκτές. Τέλος, προσομοιώνουμε το παραπάνω σύστημα με τη βοήθεια της εφαρμογής Simulink του λογισμικού MATLAB και μελετώντας τα αποτελέσματα, εξάγουμε τα ανάλογα συμπεράσματα. / This thesis deals with the study of a wind turbine device with a permanent magnet synchronous machine which is connected with the grid side via a dc interconnection. The dc link is created by a dc capacitor and on the machine side there is an ac / dc power converter while on the grid side there is a dc / ac power converter, both of which are totally controlled. Aim of this thesis is to study the complete wind turbine system in the d-q rotating vertical axes system through the Park transformation. Then we calculate the state space equations and propose a control system based on PI controllers. Finally, we simulate the complete system with the MATLAB Simulink and having studied the results, we draw conclusions.
29

Control strategy for a mono-inverter multi-PMSM system - Stability and efficiency / Stratégie de contrôle d'un système multi-PMSM mono-onduleur - Stabilité et efficacité

Liu, Tianyi 15 December 2017 (has links)
Durant ces dernières décennies, le moteur synchrone à aimants permanents (MSAP) est devenu un actionneur essentiel pour les applications militaires, industrielles et civilesgrâce à ses avantages de haute densité de puissance, de rendement élevé, de grande fiabilité avec une structure simple, un faible volume et un poids réduit. Parfois, plusieurs MSAP sont utilisés pour effectuer des tâches coopératives. Par exemple le boggie d'une locomotive ou encore les surfacesde vol d'un avion. Ces MSAP fonctionnent généralement à la même vitesse. Pour réduire le volume et le poids, une idée de mutualisation des dispositifs de conversion statique, appelée système Multi-MSAP Mono-Convertisseur (MIMSAPMC), est proposée. Bien que de nombreux chercheurs aient déjà proposé différentes solutions de contrôle pour le système MIMSAPMC, la plupart d'entre eux ne garantissent pas la stabilité et l'efficacité énergétique du système. Ceci estdevenu le plus grand obstacle à l'utilisation pratique du MIMSAPMC. A cet effet et en commençant par un système MIMSAPMC avec 2 moteurs nous avons testé expérimentalement quelques stratégies de commande pour en vérifier la faisabilité et les performances. Sur la base des données mesurées, nous avons constaté que le problème de sur-contraintes existe dans certaines stratégies de contrôle. Ensuite, la synthèse d’une commande basée sur un modèle en régime permanent d'un système MIMSAPMC est réalisée. En étudiant le problème d'existence du régime permanent, nous formulons une procédure de conception de la structure de la loi de commande. En combinant la stabilité en boucle ouverte et la solution en régime permanent, nous définissons alors la région de contrôlabilité et de stabilité. La méthode des multiplieurs de Lagrange est ensuite utilisée pour formuler l'expression de l'état d'équilibre optimal en fonction ducouple et de la vitesse. L'expérience a montré que l'efficacité avec cette nouvelle loi de commande s’est considérablement améliorée. Dans le même temps, nous avons exploré l'influence de la variation des paramètres pour la stabilité du système et pour l'optimisation de l'efficacité. Ainsi, nous montrons que la variation paramétrique influence la zone de stabilité. Mais son influence peut être éliminée en utilisant la stratégie Maitre-Esclave. Par ailleurs, en ce qui concerne l'optimisation de l'efficacité énergétique, les résultats de simulation ont montré que la non-concordance des paramètres, en particulier le flux de l’aimant, peut entraîner une perte d'efficacité élevée. Dans la dernière étape, ce contrôleur est également adapté à un système MIMSAPMC avec un nombre de moteurs supérieurs à 2. Les résultats de la simulation démontrent alors l'efficacité de la proposition. / During these decades, Permanent Magnet Synchronous Motor (PMSM) has become a vital part of military, industry and civil applications due to the advantages of high power density, high efficiency, high reliability and simple structure, small volume and light weight. Sometimes, multiple PMSMs are used to carry out cooperative functions. For example, the bogie of a locomotive, the flight control surface of an airplane. These PMSMs usually operates at the same speed. To reduce the volume and weight, an idea of sharing the static power conversion devices, which is called Mono-Inverter Multi-PMSM system (MIMPMSM), is raised. Although many researchers have given different controller solutions for the MIMPMSM system, most of them are not clear in the aspects of system stability and efficiency issues. This has become the biggest obstacle to the practical use of MIMPMSM. Oriented with these problems, starting with a MIMPMSM system with 2 motors, in the first step, we have tested some control strategies by an experiment to verify the feasibility and performance of them. In final, based on the experiment data, we have figured that the overconstraint problem exists in some control strategies. Then, an analysis and controller design based on steady-state model of a Mono-Inverter Dual-PMSM (MIDPMSM) system is carried out.By studying the solution existence problem of the steady-state model, we give out the design guideline to the controller structure. Combining the open-loop stability and steady-state solution, the region of controllability and stability is obtained. Lagrange Multiplier is used develop theexpression of efficiency-optimal steady-staterelated to torque and speed. The experiment has shown that the efficiency of the new controller has improved significantly. Meanwhile, we have explored the influence of parameter variation in system stability and efficiency-optimization. The variation will influence the stability region. But its influence can be eliminated by using Master- Slave strategy. On the other hand, in the aspect of efficiency optimization, the simulation results have shown that parameter mismatch, especially the permeant flux, can cause high efficiency loss. In the last step, this controller is also adapted to a MIMPMSM system with more than two motors. The simulation results demonstrate the effectiveness.
30

Projeto de aerogerador com segurança inerente para aplicação urbana

Verdum, Valdirene January 2013 (has links)
Esta dissertação propõe um projeto de aerogerador que é composto de uma turbina eólica de cinco pás, acoplada a um difusor e um gerador elétrico, com a finalidade de gerar energia elétrica com ventos de velocidade a partir de 4 m/s. São apresentados os pressupostos teóricos referentes ao estudo e dimensionamento aerodinâmico de uma pá, baseados principalmente na teoria do disco atuador e na teoria aerodinâmica, através do método de Betz. É feito o estudo de um difusor para ser acoplado à turbina com o objetivo de aumentar o aproveitamento energético. No final foram estudadas as principais topologias utilizadas para a geração eólica e é selecionado o gerador síncrono de ímãs permanentes. A seguir foram estudadas e dimensionadas as partes ativas do gerador (diretamente envolvidas na conversão eletromagnética). É projetado um aerogerador trifásico com enrolamentos distribuídos. O rotor, que é acoplado às pás, localiza-se internamente. Os ímãs permanentes de Neodímio-Boro-Ferro são montados na superfície do rotor. Conclui-se com a avaliação do aerogerador proposto com base nas simulações computacionais de seu desempenho. / This thesis proposes a wind generator design which combines a five blade wind turbine that is attached to a diffuser and an electrical generator. The design aims to produce electric power from 4 m/s starting wind speeds. It presents the theoretical study concerning the design and aerodynamics of a blade, commonly based on the theory of actuator disc and aerodynamic theory, through the method of Betz. A study was conducted on a diffuser to be coupled to the turbine in order to increase the energy utilization. In the end, the main topologies used for wind generation were presented, and the permanent magnet synchronous generator was selected. Next, all the active parts of the generator (directly involved in electromagnetic conversion) were studied and determined. An outer stator with three-phase distributed windings was designed. The rotor, which is coupled to the blades, is located internally. The Neodymium-Iron-Boron permanent magnets are mounted on the rotor surface. It is concluded with an evaluation of the proposed wind generator in accordance with its behavior computational simulations.

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