The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor speed measurements as control variable inputs. The dependence on the accuracy of the measurement devices makes the controller less reliable. The proposed control scheme is based on the stiff system concept and provides a fast response and a dynamic solution to the complicated aerodynamic system. This control scheme provides a response to the wind changes without the knowledge of wind speed and turbine parameters. The system consists of a permanent magnet synchronous machine (PMSM), a passive rectifier, a dc/dc boost converter, a current controlled voltage source inverter, and a microcontroller that commands the dc/dc converter to control the generator for maximum power extraction. The microcontroller will also be able to control the current output of the three-phase inverter. In this work, the aerodynamic characteristics of wind turbines and the power conversion system topology are explained. The maximum power tracking control algorithm with a variable step estimator is introduced and the modeling and simulation of the wind turbine generator system using the MATLAB/SIMULINK® software is presented and its results show, at least in principle, that the maximum power tracking algorithm developed is suitable for wind turbine generation systems.

Wind power is a fast growing alternative energy source. Since 2000, wind energy capacity has increased 24 percent per year with Texas leading the U.S. in installed wind turbine capacity. Most socioeconomic research in wind energy has focused on understanding local opposition, especially aesthetic impacts on the surrounding landscape. Recent studies have addressed reasons for social acceptance of wind farms, suggesting that positions both favorable and unfavorable to wind power are subtle and intricate, rather than monolithic, and rooted in place-specific issues. In the case of Texas, scholars have reported that the minimal permitting process is the dominant variable that explains the rapid rise of wind power in the state?s western region. However, scholars have yet to study the place-based local or regional factors that structure and inform acceptance of wind energy by key actors who negotiate with wind-energy firms. This thesis presents empirically determined, statistically significant social perspectives regarding socioeconomic wind energy impacts. I determined social perspectives by using Q-Method in Nolan County, Texas, a major site of wind-power development. Q-Method allows researchers to generalize about social perspectives, but not about how widely or deeply populations ascribe to social perspectives. Q-Method combines qualitative and quantitative techniques beginning with semi-structured interviews to collect statements on wind power, followed by participant ranking of statements on a ?most disagree? to ?most agree? scale. Key actors surveyed included landowners with wind turbines, elected and civilservice government officials, and prominent local business and community leaders. My findings identified five significant clusters of opinion, two of which shared strong support for wind energy on the basis of perceived positive economic impacts. Three clusters of opinion were less favorable to wind energy; these arguments were based upon opposition to tax abatements, support of tax abatements, and concerns over negative impacts to the community. Consensus emerged over the idea that positive views toward wind-energy development were unrelated to broader commitments to renewable energy. The support of key actors in favor of wind energy is contingent upon direct financial benefits from wind-energy royalties, political views on taxes, notions of landscape aesthetics, and sense of community.

The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor speed measurements as control variable inputs. The dependence on the accuracy of the measurement devices makes the controller less reliable. The proposed control scheme is based on the stiff system concept and provides a fast response and a dynamic solution to the complicated aerodynamic system. This control scheme provides a response to the wind changes without the knowledge of wind speed and turbine parameters. The system consists of a permanent magnet synchronous machine (PMSM), a passive rectifier, a dc/dc boost converter, a current controlled voltage source inverter, and a microcontroller that commands the dc/dc converter to control the generator for maximum power extraction. The microcontroller will also be able to control the current output of the three-phase inverter. In this work, the aerodynamic characteristics of wind turbines and the power conversion system topology are explained. The maximum power tracking control algorithm with a variable step estimator is introduced and the modeling and simulation of the wind turbine generator system using the MATLAB/SIMULINK® software is presented and its results show, at least in principle, that the maximum power tracking algorithm developed is suitable for wind turbine generation systems.

In order to consolidate a sustainable renewable energy infrastructure, the Australian state of Victoria requires an advancement and development of any feasible renewable energy alternatives. There is a large onshore wind energy market in Victoria but the state currently has no offshore wind technology under consideration or proposal. Australia, and Victoria, has a vast coast line with desirable wind resources for offshore wind implementation. In order to definitively investigate the potential for such technology, a simulation was designed to test the amount of power that could be produced in Victoria by using real life wind speed data sets. The simulation output was analyzed in conjunction with an analysis of the social, political, environmental and economic considerations that could increase or decrease the potential for this technology. 11 simulation scenarios were tested and analyzed, two of which produced a positive net present value by the conclusion of its commissioned operational life. It was found that there is the potential for development of this technology within certain locations in Victoria but it would face several barriers to implementation. The most prominent barriers are competition with a thriving coal and fossil energy industry and competition with more economically desirable alternative renewable technologies such as onshore wind energy.

Wind energy development and its stigma of avian mortality provide a case for exploring the complexities that can occur between science, law, politics, and planning. The present method of measuring mortality appears flawed and may hamper the ability of resource agencies, the public, and industry in making educated decisions about siting wind farms and protecting species. The U.S. Fish and Wildlife Service has the ability to take an active role and affect a project already constructed. The Migratory Bird Treaty Act appears to keep the issue of avian mortality within the minds of wind energy developers. Protecting species on the brink of extinction is codified in the Endangered Species Act, which seems to be well suited for protecting most species. The significance of avian mortality can be linked to public perceptions. The industry in Texas has taken the approach of not sharing avian-related data, except in very few instances. Providing such substantial federal incentives through the Production Tax Credit rather than direct federal funding bypasses the National Environmental Policy Act and its requirement that federal governments consider impacts to the environment. / text

As wind energy penetration levels increase, there is a growing interest in using storage devices to aid in managing the fluctuations in wind turbine output power. Vanadium-Redox batteries (VRB) and Lithium-Ion (Li-Ion) batteries are two emerging technologies which can provide power smoothing in wind energy systems. However, there is an apparent gap when it comes to the data available regarding the design, integration and operation of these batteries in wind systems. This thesis presents suitable battery electrical models which will be used to assess system performance in wind energy applications, including efficiency under various operating conditions, transfer characteristics and transient operation. A design, sizing and testing methodology for battery integration in converter based systems is presented. Recommendations for the development of operating strategies are then provided based on the obtained results.

A wind resource assessment of two sites in the Waterloo region, WRESTRC and RIM Park, was conducted using wind speed, wind direction, temperature and pressure data collected from meteorological towers for over two years. The study was undertaken as part of the W3 Wind Energy Project, and the equipment was purchased from NRG Systems and R. M. Young Company. The data was filtered to reduce the effect of icing and tower shadow, and was analyzed using MATLAB software. Based on the mean wind speeds, small wind turbines less than 50 kW in capacity would be appropriate at both sites. Wind speeds tended to be stronger during the winter than the summer, and during the afternoon than the rest of the day. Both sites also exhibited a strong dominant wind direction -- from the northwest. Due to the terrain, the wind shear and turbulence intensity at WRESTRC were moderate when the wind flowed from the dominant direction, but very high from other directions. The wind shear and turbulence intensity at RIM Park were consistently moderate in all directions. Although the terrain seems more complex at WRESTRC, the wind speed distribution and estimated annual energy production were higher at WRESTRC than at RIM Park, which indicates that it is a more viable site. The estimated capacity factors ranged from 9.4% to 22% depending on the hub height, which is not nearly high enough to suggest a commercial wind farm would be viable at either site. A small 5 kW to 15 kW wind turbine in the Waterloo region could offset the electricity usage of an average home. A two-parameter power law model of wind shear was explored and compared with the standard one-parameter model. In terms of goodness-of-fit, the two-parameter model did perform better. But in terms of accuracy of extrapolation, it was not conclusively better or worse than a one-parameter model forced through the known data point closest to the prediction height. The relationship between turbulence intensity and measurement interval was examined. Since atmospheric flow is unsteady, they are not independent. The perceived turbulence intensity was found to increase exponentially with time intervals under 24 hours. Two linear regression-based Measure-Correlate-Predict methods were evaluated using long-term data from a weather station also at WRESTRC. The ordinary least squares method was considered the baseline given its simplicity. The variance ratio method improved upon it by ensuring that the variance of the wind speed distribution at the target site was preserved.

Wind-hydrogen systems for remote area power supply are an early niche application of sustainable hydrogen energy. Optimal direct coupling between a wind turbine and an electrolyser stack is essential for maximum electrical energy transfer and hydrogen production. In addition, system costs need to be minimised if wind-hydrogen systems are to become competitive. This paper investigates achieving near maximum power transfer between a fixed pitched variable-speed wind turbine and a Proton Exchange Membrane (PEM) electrolyser without the need for intervening voltage converters and maximum power point tracking electronics. The approach investigated involves direct coupling of the wind turbine with suitably configured generator coils to an optimal series-parallel configuration of PEM electrolyser cells so that the I-V characteristics of both the wind turbine and electrolyser stack are closely matched for maximum power transfer. A procedure for finding these optimal con figurations and hence maximising hydrogen production from the system is described. For the case of an Air 403 400 W wind turbine located at a typical coastal site in south-eastern Australia and directly coupled to an optimally configured 400 W stack of PEM electrolysers, it is estimated that up to 95% of the maximum achievable energy can be transferred to the electrolyser over an annual period. The results of an extended experiment to test this theoretical prediction for an actual Air 403 wind turbine are reported. The implications of optimal coupling between a PEM electrolyser and an aerogenerator for the performance and overall economics of wind-energy hydrogen systems for RAPS applications are discussed.

As the demand for safe and clean electricity increases, the New Zealand wind energy industry seems poised to expand. Many generating companies have projects in the planning stage and there are likely to be many more potential sites yet to be identified. Reliable wind climate predictions over a wide area and for different heights above grounds are often vital to determine the viability of wind farm projects. This study investigates the use of meteorological mesoscale models to determine the wind and energy resource, particularly in areas of complex terrain. Complex terrain environments are likely to be typical of where New Zealand wind energy developments will take place. Using the prognostic mesoscale meteorological model TAPM (The Air Pollution Model), regions of relatively high mean wind speed were identified for a number of regions, including Banks Peninsula and parts of Canterbury and Otago. The simulations were conducted for a one-year period (2001) and at different heights above ground level. Depending on the resolution of the model calculations, speed-up effects from the forcing of some topographic features were accounted for by this model. Where the modelling was considered reliable, hourly wind data were obtained from grid points within the inner grid and used as input data for the industry-standard wind energy assessment model WAsP (The Wind Atlas Analysis and Application Program). As WAsP is able to account for detailed topography and surface roughness features, wind and energy predictions at a specific site or over a wider area surrounding the site were made. Limitations of both models in complex terrain were identified. These limitations were due to a number of factors, including the grid spacing used for mesoscale model calculations, the complexity of the terrain, and difficulties in modelling some regional scale airflow regimes. Being aware of when and where model limitations are likely to occur is important in being able to overcome and account for them.

Thesis supervisor: Andrew Kusiak. Includes bibliographic references (p. 141-147).