الفهرس 
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Abstract
The performance of the Wind Energy Conversion System (WECS) in electrical generation has received considerable attention nowadays. The aim of this work is to design a WECS to convert wind power to electrical power. The work would include developing a reliable controller to extract the maximum electric power generated from the WECS. This controller is designed to adjust the electric power supplied to the load to follow the maximum power available from Wind Energy (WE). In addition, proper operation of the system at wide range of operating conditions is targeted. A mathematical model of the WECS is derived. Modeling and simulation of the whole system was performed using MA TLAB/SIMULINK developed program to analyze the system and to get reliable results that will be compared with the experimental results. Then open loop system response is studied according to different operating conditions with various disturbances. The closed loop system response due to different disturbances is also studied. A Proportional plus Integral (PI) controller to extract the maximum power from the WECS, by updating the Modulation Index (MI) of the Pulse Width Modulation (PWM) inverter to ensure maximum power tracking, is designed. Detailed study was carried out to investigate the system performance under various operating conditions. A laboratory model of the WECS is designed and implemented. The Wind Turbine (WT) is represented practically by a separately excited DC motor fed from a half-controlled rectifier bridge. Switching instant and consequently the inverter output voltage are directly controlled by a developed computer program to obtain the maximum electric power generation. Various numbers of testes for open loop and closed loop system were obtained and anaiyzed. This results include step change in wind speed (increasing and decreasing), pulse change in wind speed and pulse change in load resistance. from the experimental and theoretical results, it is concluded that, with using the proposed control technique, the system produces a maximum power corresponding to the specified wind speed. Also the value of this power depends only on the wind speed whatever the value of the load. In addition, the system ability to recover from large disturbances is improved. So, the theoretical study and the practical results obtained reflect the effectiveness of the aspects and ideas considered in this work.