8997

8342

كارشناسي ارشد

قدرت

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1392

نه،82ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

احمدرضا تابش

مهدي معلم

18/3/93

مهندسي برق و كامپيوتر

ID8342

84 Reducing dc link Capacitor in direct drive Wind turbine generators using Multi phase Axial Flux Permanent Magnet Machines Samaneh Pirpour s pirpour@ec iut ac ir Date of Submission 2013 3 10 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Ahmadreza Tabesh a tabesh@cc iut ac ir Abstract Ever in creasing demand for electric energy volatile cost of energy from fossil fuel resources and more importantly the environmental concerns have caused government incentive polices for deployment of renewable energy technologies As a result of these incentives during the last couple of decades currently large scale wind power systems in terms of levelised cost of energy index can economically compete with fossil fuel resources Advances in power electronics and silicon based photovoltaic PV cells also have made the PV energy systems among promising renewable energy resource even in utility scales Currently several PV power plants in the order of tens of mega watt are operational all over the world and a few hundred mega watt PV power plants are also under construction which will be operational in less than five years In wind power technology one of the main challenges is capturing wind energy at an area with low speed wind distribution The direct drive wind turbine generator topology without gearbox has been suggested as a promising solution for capturing the wind energy more efficiently at a low wind speed This topology basically requires high pole generators to capture wind power at high torques and low rotational speeds Furthermore it requires a high power electronic interface circuit with a robust topology to deliver the captured wind power to a grid This thesis along the recent researches on direct drive wind turbine topologies deals with modeling and control of an axial flux permanent magnet AFPM for wind power system with diode interfaced power converter AFPMs due to their robust structures ease of assembly and high torque power densities are among the promising options for direct drive applications In the first part of this thesis a method for dynamic modeling of AFPMs is proposed which is useful for performance analysis and the design of speed control drives for multi phase AFPMs The validity of the suggested model has been verified via simulation and experimental test results under sinusoidal and non sinusoidal voltage terminals Furthermore a grid connected inverter based on hystersis strategy is implemented and tested on a 45 phase AFPM in ordet to presents a solution for reducing the size of dc link capacitor due to decreasing the dc link voltage ripples and compared with conventional 3 phase dc ac inverters It has been shown that by using high pole multi phase AFPMs the electrolyte capacitors can be even replaced with ac film capacitors Reducing the size of capacitor extends the life time of wind energy system since the electrolyte capacitor is a weak link especially in high power applications The performance of poly phase machine and the suggested power inverter with reduced capacitor is also investigated using a test setup developed for a 45 phase AFPM connected to the grid Key word Direct drive wind turbine generators Dynamic modeling Electrolyte capacitor less inverters Poly phase axial flux generators PDF created with pdfFactory trial version www pdffactory com

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