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The Simulation And Control Of A Grid-connected Wind Energy Conversion SystemMcCartney, Shauna 01 January 2010 (has links)
With the rising cost of petroleum, concerns about exhausting the fossil fuels we depend on for energy, and the subsequent impacts that the burning of these types of fuels have on the environment, countries around the world are paying close attention to the development of renewable types of energy. Consequently, researchers have been trying to develop ways to take advantage of different types of clean and renewable energy sources. Wind energy production, in particular, has been growing at an increasingly rapid rate, and will continue to do so in the future. In fact, it has become an integral part in supplying future energy needs, making further advancements in the field exceedingly critical. A 2 MW wind energy conversion system (WECS) is presented and has been simulated via the dynamic simulation software Simulink. This WECS consists of a 2 MW permanent magnet synchronous generator connected to the transmission grid through a power conversion scheme. The topology of this converter system consists of a passive AC/DC rectifier as well as a PWM DC/AC IGBT inverter, used to interface the DC link with the grid. The inverter has an integrated current control system for power factor correction to improve output power stability. The described WECS enhances grid-side tolerance by buffering wind power disturbances demonstrated by its capability to isolate the grid from wind speed fluctuations. It also optimizes wind energy capture through harmonic filtering, enhancing output power quality. These findings have the potential to lead to further advancements including the capability for island operation and integration to a smart grid.
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DFIG-Based Split-Shaft Wind Energy Conversion SystemsAkbari, Rasoul 08 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / In this research, a Split-Shaft Wind Energy Conversion System (SS-WECS) is investigated
to improve the performance and cost of the system and reduce the wind power
uncertainty influences on the power grid. This system utilizes a lightweight Hydraulic Transmission
System (HTS) instead of the traditional gearbox and uses a Doubly-Fed Induction
Generator (DFIG) instead of a synchronous generator. This type of wind turbine provides
several benefits, including decoupling the shaft speed controls at the turbine and the generator.
Hence, maintaining the generator’s frequency and seeking maximum power point
can be accomplished independently. The frequency control relies on the mechanical torque
adjustment on the hydraulic motor that is coupled with the generator. This research provides
modeling of an SS-WECS to show its dependence on mechanical torque and a control
technique to realize the mechanical torque adjustments utilizing a Doubly-Fed Induction
Generator (DFIG). To this end, a vector control technique is employed, and the generator
electrical torque is controlled to adjust the frequency while the wind turbine dynamics
influence the system operation. The results demonstrate that the generator’s frequency is
maintained under any wind speed experienced at the turbine.
Next, to reduce the size of power converters required for controlling DFIG, this research
introduces a control technique that allows achieving MPPT in a narrow window of generator
speed in an SS-WECS. Consequently, the size of the power converters is reduced
significantly. The proposed configuration is investigated by analytical calculations and simulations
to demonstrate the reduced size of the converter and dynamic performance of the
power generation. Furthermore, a new configuration is proposed to eliminate the Grid-
Side Converter (GSC). This configuration employs only a reduced-size Rotor-Side Converter
(RSC) in tandem with a supercapacitor. This is accomplished by employing the hydraulic
transmission system (HTS) as a continuously variable and shaft decoupling transmission
unit. In this configuration, the speed of the DFIG is controlled by the RSC to regulate the
supercapacitor voltage without GSC. The proposed system is investigated and simulated in
MATLAB Simulink at various wind speeds to validate the results.
Next, to reduce the wind power uncertainty, this research introduces an SS-WECS where the system’s inertia is adjusted to store the energy. Accordingly, a flywheel is mechanically
coupled with the rotor of the DFIG. Employing the HTS in such a configuration allows the
turbine controller to track the point of maximum power (MPPT) while the generator controller
can adjust the generator speed. As a result, the flywheel, which is directly connected
to the shaft of the generator, can be charged and discharged by controlling the generator
speed. In this process, the flywheel energy can be used to modify the electric power generation
of the generator on-demand. This improves the quality of injected power to the
grid. Furthermore, the structure of the flywheel energy storage is simplified by removing
its dedicated motor/generator and the power electronics driver. Two separate supervisory
controllers are developed using fuzzy logic regulators to generate a real-time output power
reference. Furthermore, small-signal models are developed to analyze and improve the MPPT
controller. Extensive simulation results demonstrate the feasibility of such a system and its
improved quality of power generation.
Next, an integrated Hybrid Energy Storage System (HESS) is developed to support the
new DFIG excitation system in the SS-WECS. The goal is to improve the power quality
while significantly reducing the generator excitation power rating and component counts.
Therefore, the rotor excitation circuit is modified to add the storage to its DC link directly.
In this configuration, the output power fluctuation is attenuated solely by utilizing the RSC,
making it self-sufficient from the grid connection. The storage characteristics are identified
based on several system design parameters, including the system inertia, inverter capacity,
and energy storage capacity. The obtained power generation characteristics suggest an energy
storage system as a mix of fast-acting types and a high energy capacity with moderate
acting time. Then, a feedback controller is designed to maintain the charge in the storage
within the required limits. Additionally, an adaptive model-predictive controller is developed
to reduce power generation fluctuations. The proposed system is investigated and simulated
in MATLAB Simulink at various wind speeds to validate the results and demonstrate the
system’s dynamic performance. It is shown that the system’s inertia is critical to damping
the high-frequency oscillations of the wind power fluctuations. Then, an optimization approach
using the Response Surface Method (RSM) is conducted to minimize the annualized
cost of the Hybrid Energy Storage System (HESS); consisting of a flywheel, supercapacitor, and battery. The goal is to smooth out the output power fluctuations by the optimal
size of the HESS. Thus, a 1.5 MW hydraulic wind turbine is simulated, and the HESS is
configured and optimized. The direct connection of the flywheel allows reaching a suitable
level of smoothness at a reasonable cost. The proposed configuration is compared with the
conventional storage, and the results demonstrate that the proposed integrated HESS can
decrease the annualized storage cost by 71 %.
Finally, this research investigates the effects of the reduced-size RSC on the Low Voltage
Ride Through (LVRT) capabilities required from all wind turbines. One of the significant
achievements of an SS-WECS is the reduced size excitation circuit. The grid side converter is
eliminated, and the size of the rotor side converter (RSC) can be safely reduced to a fraction
of a full-size excitation. Therefore, this low-power-rated converter operates at low voltage
and handles the regular operation well. However, the fault conditions may expose conditions
on the converter and push it to its limits. Therefore, four different protection circuits are
employed, and their effects are investigated and compared to evaluate their performance.
These four protection circuits include the active crowbar, active crowbar along a resistorinductor
circuit (C-RL), series dynamic resistor (SDR), and new-bridge fault current limiter
(NBFCL). The wind turbine controllers are also adapted to reduce the impact of the fault
on the power electronic converters. One of the effective methods is to store the excess energy
in the generator’s rotor. Finally, the proposed LVRT strategies are simulated in MATLAB
Simulink to validate the results and demonstrate their effectiveness and functionality.
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Improved Dynamical Analysis Tools for DFIG Wind Farms via Traditional and Koopman LinearizationsMitchell-Colgan, Elliott 27 September 2019 (has links)
The electric power system is designed to economically and reliably transmit electricity to homes, industry, and businesses. The economic impact of the electric grid was demonstrated by the 2003 blackout's visible impact in the graph of the yearly gross domestic product of the Unites States. However, because the number of customers is so large and economies of scale are leveraged to keep electricity prices low, utilities are strongly interconnected.
Performing comprehensive engineering analyses to ensure reliable operation is still impossible. Instead, heuristics and safety factors are incorporated into planning processes to continually meet demand in a way that complies with Federal regulations. As evidenced by the infrequency of blackouts in the United States, the sophisticated planning processes have up to date been relatively successful.
However, the power system is constantly changing. Electrical generators based on renewable energies are a beneficial addition to the grid, but these and other technological changes like high-voltage power electronic converters also come with their own challenges. These systems as currently employed tend to have a different impact on the reliability of operation than traditional fossil fuel based generators. As the system changes, so do the engineering analyses required to ensure reliable operation.
In particular, the wind energy conversion systems (WECS) negatively impact the response of the grid to disturbances in certain ways due to inherent challenges harnessing the wind as an energy sources. These negative impacts (and the advent of powerful personal computing) require an increase in the sophistication of power system models.
Thus, there are competing challenges: the scale of the power system necessitates computationally efficient modeling, but the complexity of analysis required to maintain reliable operation is also increasing. The primary aim of this study is to develop models and methods for more detailed yet computationally manageable simulation. To this aim, higher order linearizations and the properties of linear systems (graph theory and linear algebra) are exploited.
More specifically, this document contains three studies. In the short term planning and situational awareness context, a method is proposed to quickly check credible outages of important grid equipment. This methodology enables the inspection of a wider breadth of system conditions to ameliorate the negative impacts of the unpredictability of the wind. A linear model in the traditional sense is also developed to model any arbitrary number of wind turbines in a wind farm. This enables industry players to study the impacts wind turbine interaction on the dynamic stability of the grid in response to small disturbances. Finally, a wind farm is modeled as a large matrix to model even nonlinear behavior of wind farms. This helps industry players analyze the impact of large disturbances on the grid. / Doctor of Philosophy / The electric power system is designed to economically and reliably transmit electricity to homes, industry, and businesses. The economic impact of the electric grid was demonstrated by the 2003 blackout’s visible impact in the graph of the yearly gross domestic product of the United States. However, because the number of customers is so large and economies of scale are leveraged to keep electricity prices low, utilities are strongly interconnected. Performing comprehensive engineering analyses to ensure reliable operation is still impossible. Instead, heuristics and safety factors are incorporated into planning processes to continually meet demand in a way that complies with Federal regulations. As evidenced by the infrequency of blackouts in the United States, the sophisticated planning processes have up to date been relatively successful. However, the power system is constantly changing. Electrical generators based on renewable energies are a beneficial addition to the grid, but these and other technological changes like high-voltage power electronic converters also come with their own challenges. These systems as currently employed tend to have a different impact on the reliability of operation than traditional fossil fuel based generators. As the system changes, so do the engineering analyses required to ensure reliable operation. In particular, the wind energy conversion systems (WECS) negatively impact the response of the grid to disturbances in certain ways due to inherent challenges harnessing the wind as an energy sources. These negative impacts (and the advent of powerful personal computing) require an increase in the sophistication of power system models. Thus, there are competing challenges: the scale of the power system necessitates computationally efficient modeling, but the complexity of analysis required to maintain reliable operation is also increasing. The primary aim of this study is to develop models and methods for more detailed yet computationally manageable simulation. To this aim, higher order linearizations and the properties of linear systems (graph theory and linear algebra) are exploited. More specifically, this document contains three studies. In the short term planning and situational awareness context, a method is proposed to quickly check credible outages of important grid equipment. This methodology enables the inspection of a wider breadth of system conditions to ameliorate the negative impacts of the unpredictability of the wind. A linear model in the traditional sense is also developed to model any arbitrary number of wind turbines in a wind farm. This enables industry players to study the impacts wind turbine interaction on the dynamic stability of the grid in response to small disturbances. Finally, a wind farm is modeled as a large matrix to model even nonlinear behavior of wind farms. This helps industry players analyze the impact of large disturbances on the grid.
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The specification of a small commercial wind energy conversion system for the South African Antarctic Research Base SANAE IVStander, Johan Nico 12 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--Stellenbosch University, 2008. / The sustainability and economy of the current South African National Antarctic
Expedition IV (SANAE IV) base diesel-electric power system are threatened by
the current high fuel prices and the environmental pollution reduction obligations.
This thesis presents the potential technical, environmental and economical
challenges associated with the integration of small wind energy conversion system
(WECS) with the current SANAE IV diesel fuelled power system. Criteria
derived from technical, environmental and economic assessments are applied in
the evaluation of eight commercially available wind turbines as to determine the
most technically and economically feasible candidates.
Results of the coastal Dronning Maud Land and the local Vesleskarvet cold
climate assessments based on long term meteorological data and field data are
presented. Field experiments were performed during the 2007-2008 austral
summer. These results are applied in the generation of a wind energy resource
map and in the derivation of technical wind turbine evaluation criteria.
The SANAE IV energy system and the electrical grid assessments performed are
based on long term fuel consumption records and 2008 logged data. Assessment
results led to the identification of SANAE IV specific avoidable wind turbine grid
integration issues. Furthermore, electro-technical criteria derived from these
results are applied in the evaluation of the eight selected wind turbines.
Conceptual wind turbine integration options and operation modes are also
suggested.
Wind turbine micro-siting incorporating Vesleskarvet specific climatological,
environmental and technical related issues are performed. Issues focusing on wind
turbine visual impact, air traffic interference and the spatial Vesleskarvet wind
distribution are analysed. Three potential sites suited for the deployment of a
single or, in the near future, a cluster of small wind turbines are specified.
Economics of the current SANAE IV power system based on the South African
economy (May 2008) are analysed. The life cycle economic impact associated
with the integration of a small wind turbine with the current SANAE IV power
system is quantified. Results of an economic sensitivity analysis are used to
predict the performance of the proposed wind-diesel power systems. All wind
turbines initially considered will recover their investment costs within 20 years
and will yield desirable saving as a result of diesel fuel savings, once integrated
with the SANAE IV diesel fuelled power system.
Finally, results of the technical and economical evaluation of the selected
commercially available wind turbines indicated that the Proven 6 kWrated, Bergey
10 kWrated and Fortis 10 kWrated wind turbines are the most robust and will yield
feasible savings.
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The regulation of Section 17 (2a) of the German Energy Economy Act against the background of current developments of the German and European offshore wind industryFischer, Felix Friedrich 12 1900 (has links)
Thesis (MBA (Business Management))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: With the introduction of Section 17 of the EnWG (German Energy Economy Act), the legislator created a new situation for the complex relationships in the German offshore wind industry. The transmission system operators are now obliged not only to provide the connection for offshore wind farms, but also to reimburse the developers of such plants for the costs they incurred in the course of planning the cable connection between the wind farm and the onshore grid. Forecasts had predicted that by 2007 numerous offshore wind farms would be operational. But no development company in the entire sector had moved beyond the planning phase. However, the rapid development of the offshore wind industry is important in order to achieve the German goal to generate 20% of all energy from renewable energy sources by 2020 and thus contribute to the prevention of grave climate changes. It is also important for the domestic labour market and the initiation of further exports of energy technologies. Early domestic growth will eventually payoff as offshore wind energy is implemented by more countries, which will then rely on the experience of German companies. Under these circumstances, Section 17 (2a) S.3 of the EnWG induces a positive impulse for offshore development. Under the financial constraints that dampened the expectations of developers of offshore wind farms, the suggested reimbursement will offer welcome relief. However a broad interpretation of Section 17 (2a) S.3 of the EnWG must be applied in order to reach the goal of actually enhancing offshore development, as is the legislator's intent. Such a broad interpretation of the reimbursement claim will lead to rapid implementation of the new law, as this will be in the interest of the developers and transmission system operators. The developers will have a large interest in beginning with the actual construction of the wind farm, and the transmission system operators will need to proceed with the planning of the cable connection. Even though improvements remain necessary the introduction of Section 17 (2a) S.3 EnWG can be considered a success. / AFRIKAANSE OPSOMMING: Met die inwerkingstelling van afdeling 17 van die EnGW (Duitse Energie Ekonomie Wet), het die regering 'n nuwe situasie geskep vir die komplekse verhouding in die Duitse see-gebonde wind-energie industrie. Die transmissie stelsel operateurs word nou verplig om nie net die verbinding met die wind-plaas te verskaf nie, maar moet ook die ontwikkelaar van die aanleg vergoed vir enige kostes wat hulle aangegaan het met die beplanning van die verbinding tussen die windplaas en die elektrisiteits-netwerk. Vooruitskattings het voorspel dat verskeie see-gebonde windplase operasioneel sou wees teen 2007. Geen ontwikkelingsmaatskappy het egter al tot dusver verder as die beplanningstadium gevorder nie. Desnieteenstaande, die spoedige ontwikkeling van die see-gebonde wind industrie is onontbeerlik in die Duitse mikpunt om 20% van energiebehoeftes op te wek vanuit hernubare bronne teen 2020 en om dus klimaatsverandering teen te werk. Dit is ook belangrik vir werkskepping in Duitsland en vir die uitvoer van energie tegnologie. Spoedige groei in die industrie sal uiteindelik dividende lewer soos seegebonde wind-energie deur ander lande ontwikkel word en gevolglik op Duitse ervaring moet staatmaak. Onder hierdie omstandighede het afdeling 17 (2a) 5.3 van die EnGW 'n positiewe effek op seegebonde ontwikkeling. As gevolg van die dempende effek wat finansiele beperkinge het op die verwagtinge van ontwikkelaars sal die terugbetalings welkome verligting bied. Dit is egter nodig om 'n bree interpretasie van afdeling 17 (2a) 5.3 van die EnGW te gebruik om die mikpunt van werklike bevordering van seegebonde ontwikkeling te bewerkstellig soos die wetgewer beoog. So 'n bree interpretasie sal lei tot spoedige implimentasie van die nuwe wet omdat dit in die belang van ontwikkelaars en transmissie-netwerk eienaars sal wees. Die ontwikkelaars sal baat daarby om spoedig met ontwikkeling te begin, terwyl die netwerk operateurs vordering sal moet maak met die beplanning van die kabel-verbinding. Ten spyte daarvan dat verdere verbeteringe nodig is kan die inwerkingstelling van afdeling 17 (2a) 5.3 van die EnGW as 'n sukses gereken word.
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Development of biomimetic control strategies for the optimal use of renewable sources and energy storage systems /Hapke, Hannes Max. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 108-114). Also available on the World Wide Web.
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The dynamics of two-dimensional cantilevered flexible plates in axial flow and a new energy-harvesting concept /Tang, Liaosha, 1970- January 2007 (has links)
No description available.
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A Parametric Study on Power Variation for Model Wind Turbine ArraysDeLucia, Dominic 28 August 2013 (has links)
This thesis presents the results of wind tunnel experiments performed for various model wind turbine arrays. The aim is to understand how siting affects power output. To optimize wind farm efficiency the experiments vary the parameters of the model wind turbines and the layout of the wind turbine array. The parameters include the alignment, height, spacing, and the rotational direction of the model wind turbines. These experiments employ mechanical torque sensors to simultaneously measure the torque and rotor angular velocity, which yields a direct measurement of the fluid mechanical power extracted by the turbine at multiple locations. For a 4 × 3 array, the power is calculated at the center turbine in each of the rows. Variations in wind farm efficiency ranging from 55% to 90% are observed between the 13 different layouts tested. Modifications to the layout of the wind turbine array clearly affects the power output of the wind turbines downstream. The results of such experiments highlight the importance of studying the relationship between wind farm layout and power output.
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Contribution à l'étude des convertisseurs statiques AC-DC-AC tolérants aux défauts / Contribution to the study of fault tolerant AC-DC-AC convertersShahbazi, Mahmoud 17 September 2012 (has links)
Les convertisseurs statiques triphasés AC/DC/AC à structure tension sont largement utilisés dans de nombreuses applications de puissance. La continuité de service de ces systèmes ainsi que leur sécurité, leur fiabilité et leurs performances sont aujourd'hui des préoccupations majeures de ce domaine lié à l'énergie. En effet, la défaillance du convertisseur peut conduire à la perte totale ou partielle du contrôle des courants de phase et peut donc provoquer de graves dysfonctionnements du système, voire son arrêt complet. Afin d'empêcher la propagation du défaut aux autres composants du système et assurer la continuité de service en toute circonstance lors d'une défaillance du convertisseur, des topologies de convertisseur "fault tolerant" associées à des méthodes efficaces et rapides de détection et de compensation de défaut doivent être mises en oeuvre. Dans ce mémoire, nous étudions la continuité de service de trois topologies de convertisseurs AC/DC/AC avec ou sans redondance, lors de la défaillance d'un de leurs interrupteurs. Deux applications sont ciblées : l'alimentation d'une charge RL triphasée et un système éolien de conversion de l'énergie basé sur une MADA. Un composant FPGA est utilisé pour la détection du défaut, afin de réduire autant que possible son temps de détection. Des variantes permettant d'optimiser la méthode de détection de défaut sont également proposées et évaluées. Les trois topologies de convertisseurs proposées, associées à leurs contrôleurs, ont été validées de la modélisation/ simulation à la validation sur banc de test expérimental, en passant par le prototypage "FPGA in the Loop" du FPGA, destiné plus spécifiquement à la détection du défaut / AC/DC/AC converters are widely being used in a variety of power applications. Continuity of service of these systems as well as their reliability and performances are now of the major concerns. Indeed, the failure of the converter can lead to the total or partial loss of the control of the phase currents and can cause serious system malfunction or shutdown. Thus, uncompensated faults can quickly endanger the system. Therefore, to prevent the spread of the fault to the other system components and to ensure continuity of service, fault tolerant converter topologies associated to quick and effective fault detection and compensation methods must be implemented. In this thesis, we present the continuity of service of three AC/DC/AC fault tolerant converters with or without redundancy, in the presence of a fault in one of their switches. Two types of applications are studied: the supply off a three-phase charge and a wind energy conversion system based on a DFIG. An FPGA based implementation is used for fault detection, in order to reduce the detection time as much as possible. Three optimizations in the fault detection method are also presented. During these researches, the three proposed converter topologies and their controllers are validated in simulations and also experimentally, while being validated in a "FPGA in the Loop" prototyping
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Study of the integration method on the control of wind power systemWang, Tian Xiang January 2009 (has links)
University of Macau / Faculty of Science and Technology / Department of Electrical and Electronics Engineering
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