DOUBLY FED INDUCTION GENERATOR CONTROL FOR WIND POWER GENERATION

Abstract

Wind power is the world's fastest growing energy sources. There are many thousands of wind turbines operating, with a total capacity 94,123 MW of which India account for 8000 MW with an annual growth of 27%. In recent years Wind energy technology has experienced important improvements due to increased penetration of wind power into electricity grid. Wind energy conversion systems become a focal point in the research of renewable energy sources. Most of the existing large systems are built or planned to run at constant speed in synchronization with a utility grid. The transition from fixed speed to variable speed wind turbines has been a significant improvement in this technology. Doubly fed induction generator wind turbines are largely developed due to their variable speed feature. The response of wind turbine to grid disturbance is an important issue, especially since the rated power of the wind turbine is increases therefore it is important to study the effect of grid disturbances on the wind turbine. Under the present dissertation the characteristics of fixed speed induction generator and doubly fed induction generator during wind speed fluctuation and grid disturbance are studied. MATLAB/Simulink software has been used to observe the characteristics of wind turbines during wind speed fluctuation and during fault on network. Simulation results show that fixed speed induction generator wind turbine system will provide fluctuation in generated voltage as well as generated power as wind speed varies also this system shows poor system stability during system disturbances. Whereas doubly fed induction generator wind turbine system shows improved system stability during wind speed variation and power system disturbances. Power electronics converters used in DFIG system is the most sensitive parts of the variable speed wind turbines with regards to system disturbances. To protect is from excessive current DFIG system is equipped with over current and DC voltage overload protection system which trip the system under abnormal conditions. iv