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.

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.

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.

Made available in DSpace on 2014-12-17T14:55:08Z (GMT). No. of bitstreams: 1 FranciscoAFM.pdf: 1422041 bytes, checksum: 5ba006636ee4d36b274ed24d386fab11 (MD5) Previous issue date: 2007-12-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / At present, the electricity generation through wind energy has an importance growing in the world, with the existence of very large plans for future wind power installation worldwide. Thus, the increasing the electricity generation through wind power requires, more and more, analysis of studies of interaction between wind parks and electric power systems. This paper has as purposes to implement equivalent models for synchronous wind generators to represent a wind park in ATP program and to check behavior of the models through simulations. Simulations with applications of faults were achieved to evaluate the behavior of voltages of system for each equivalent model, through comparisons between the results of models proposed, to verify if the differences obtained allows the adoption of the simplest model / A gera??o de eletricidade atrav?s da energia e?lica teve, recentemente, um importante crescimento em todo planeta, com a exist?ncia de v?rios planos de instala??es de pot?ncia e?lica para o futuro. Dessa forma, o aumento na gera??o de eletricidade atrav?s da energia e?lica requer, cada vez mais, an?lise de estudos da intera??o entre os parques e?licos e os sistemas el?tricos de pot?ncia. Este trabalho tem como objetivos implementar modelos equivalentes de aerogeradores s?ncronos para representar um parque e?lico no programa ATP e examinar o comportamento dos modelos atrav?s de simula??es. Simula??es com aplica??es de faltas foram realizadas para avaliar o comportamento das tens?es do sistema para cada modelo equivalente, atrav?s de compara??es entre os resultados dos modelos propostos, para verificar se as diferen?as obtidas permitem a ado??o do modelo mais simples

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.

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.

The main objective of the master`s thesis was to prove, if permanent magnet synchronous generator made by company JULI Motorenwerk s.r.o. could reach higher maximum active power with active rectifier than with six-pulse bridge rectifier. For this reason a mathematical model was made in Matlab/Simulink. The influence of the rectifiers with various kinds of loading was observed and compared by simulations on output variables, like line-to-line voltage and active power. The simulations were also compared with measurement.

No description available.

This work focuses on the safe and stable operation of an autonomous power system interconnecting an AC source with various types of power electronic loads. The stability of these systems is a challenge due to the inherent nonlinearity of the circuits involved. Traditionally, the stability analysis in this type of power systems has been approached by means of small-signal methodology derived from the Nyquist stability criterion. The small-signal analysis combined with physical insight and the adoption of safety margins is sufficient, in many cases, to achieve a stable operation with an acceptable system performance. Nonetheless, in many cases, the margins adopted result in conservative measures and consequent system over designs. This work studies the system stability under large-perturbations by means of three different tools, namely parameter space mapping, energy functions, and time domain simulations. The developed parameters space mapping determines the region of the state and parameter space where the system operation is locally stable. In this way stability margins in terms of physical parameters can be established. Moreover, the boundaries of the identified stability region represent bifurcations of the system where typical nonlinear behavior appears. The second approach, based on the Lyapunov direct method, attempts to determine the region of attraction of an equilibrium point, defined by an operation condition. For this a Lyapunov function based on linear matrix inequalities was constructed and tested on a simplified autonomous system model. In Addition, the third approach simulates the system behavior on a computer using a detailed system model. The higher level of model detail allows identifying unstable behavior difficult to observe when simpler models are used. Because the stability of the autonomous power system is strongly associated with the characteristics of the energy source, an improved voltage controller for the generator is also presented. The generator of an autonomous power system must provide a good performance under a wide variety of regimes. Under these conditions a model based controller is a good solution because it naturally adapts to the changing requirements. To this extent a controller based on the model of a variable frequency synchronous generator has been developed and tested. The results obtained show a considerable improvement performance when compared to previous practices. / Ph. D.

The grid code, FIKS, from the Norwegian transmission system operator (TSO), Statnett, states that synchronous generators > 25MVA, must have a static excitation system. However, an improved brushless excitation system is in operation on some commercial power plants (36MVA, 93.75rpm & 52MVA, 166.67rpm) with grid-assisting performance beyond the conventional static system. The convenional diode bridge is replaced with a remote-controlled thyristor bridge on the shaft. If wireless communication is not allowed, a control signal through brushes should be employed instead. The thesis explores the expected new era for large brushless hydrogenerators. The proposed brushless system have benefits of reduced regular maintenance due to elimination of brushes and reduced unscheduled maintenance due to redundancy; causing a redused cost-of-energy. A six-phase exciter design with a hybrid-mode thyristor bridge interface leads to improved fault-tolerance, better controllability, minimized torque pulsations and reduced armature currents of the exciter. Excitation boosting (EB) capability is included in the brushless system without additional components or circuitry, contrary to the static excitation system. The brushless excitation system is made insensitive to voltage dips in the interconnected grid, causing improved fault ride-through (FRT) capability and power system stabilizer (PSS) actions.