Performance analysis of converter based variable speed wind energy conversion system

In this paper performance study of converter based wind energy conversion system (WECS) has been obtained. The generator used in WECS for this study is a permanent magnet alternator (PMA) coupled to a wind turbine. It is assumed that the wind speed varies widely at the chosen site of WECS. The wide fluctuation of the wind speed produces variable dc voltage across the ac/dc converter stage. A dc-dc buck converter stage has been proposed to be used in such a situation to robustly hold the output dc voltage to the desired constant value needed for the dc link of the PWM inverter. It is shown through the small-signal modeling of the buck converter that the system has sufficient stability margins to control the output voltage and provide insensitivity against variations in the input voltage due to wind speed variations. Both dc output voltage of the buck converter and ac output voltage of the inverter are controlled through a common control strategy. The proposed wind energy scheme has been simulated and analyzed in the MATLAB/SIMULINK platform for different wind speed variations. The experimental verification of the performance of the buck converter to be used for the WECS has been obtained on the laboratory model using a dc motor-synchronous generator set.