8335

7733

كارشناسي ارشد

قدرت

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1392

نه،104ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمد ابراهيمي

غلامرضا يوسفي

3/10/92

حميدرضا كارشناس، احمدرضا تابش

مهندسي برق و كامپيوتر

ID7733

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Improved Direct Decoupled Active and Reactive power control of DFIG by Improvement of Stator Flux Damping Mohammad Hashemi mhashemi@ec iut ac ir Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mohammad Ebrahimi mebrahim@cc iut ac irAbstract Among different kinds of renewable energy resources wind energy has had the fastest growth inelectrical power generation all around the world Converting the wind kinetic energy to electrical energy isdone by using a wind turbine connected to an electrical generator One of the generators which is used forthis purpose is doubly fed induction generator In this machine torque and electrical power of the machine sstator can be controlled by feeding the rotor windings with proper voltages Several methods have been proposed for controlling this machine s power components directly whichare classified as DPC methods It has been shown that in order to have a good performance powercomponents control should be decoupled In one of these methods it has been shown that in a DFIM directand decoupled control of power components of the stator can be achieved by controlling of quadrature anddirect components of the rotor flux In this method correct reference rotor flux components are calculatedby estimating direct and quadrature stator flux components from the power commands with regards to thestator resistance In above method of power control poorly damped oscillations are seen in stator s active and reactivepower and electromagnetic torque of the machine In this thesis the linear model of the whole controlsystem is obtaind in grid flux referenc frame assuming that the amplitude and frequency of the statorvoltages are constant By using this model it is shown that the cited oscillations refer to the poorly dampedpoles of the contol system which have an important role in forming stator flux of the DFIM Afterwards itis shown that these poles damping cannot be improved by changing integral and proportional gains of PIcontrollers which are used in this method Because of the control system high order this analysis is donenumerically and in the specific range of 100 of normal integral and proportional gain values Then according to the transition matrix of the contol system the entries of the transition matrix that affect the realpart of these poorly damped poles are recognized and two methods are proposed for improvement of thesepoles damping Finally Simulation results are presented in both improved and not improved systems inorder to verify the proposed methods Comparison of stator flux active power reactive power andelectromagnetic torque figures in improved and not improved direct decoupled contol systems shows theeffectiveness of the proposed methods Keywords Renewable Energy Resources Doubly Fed Induction Machine DFIM Direct PowerControl DPC Direct Decoupled Power Control DDPC Transition Matrix PIController

محمد ابراهيمي

غلامرضا يوسفي

حميدرضا كارشناس، احمدرضا تابش