الفهرس 
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Abstract
Nowadays, the most currently installed variable speed wind turbines are based on doubly fed induction generator (DFIG). In this thesis, a revision for the objectives and techniques used in the control of DFIG will be presented. A D-Q model for the simulation and the analysis of a double-fed induction generator is developed. A simulation for the stand alone DFIG with inverter controlled by 180° conduction will be considered. A comparison between the simulation and experimental results is performed to verify the output voltage and frequency. In order to improve the performance of the output waveform, the space vector pulse width modulation (SVPWM) technique is used for controlling the stand alone DFIG. A complete study and simulation for the self-excited DFIG using SVPWM will be presented. A grid-connected DFIG for wind-turbine system is also studied to control both active and reactive power under variable speed operation; this includes both subsynchronous and super-synchronous speeds.