Voltage and frequency stability for control of stand-alone DFIG-based wind turbine using direct voltage control method

In this paper the stability of voltage and frequency in Doubly fed induction generator for a variable speed wind turbine in stand-alone mode is analyzed and simulated. Important equations governing on the stand-alone structure has been discussed and then the control loops of Rotor Side Converter (RSC) and Load Side Converter (LSC) are analyzed and designed. Two methods of direct and indirect stator voltage control method are also introduced and compared, and due to advantages of direct voltage control method, this method has been used. during the system´s changes, voltage and frequency of the stator is stabilizes and regulated on a constant value by using vector control method and selecting the stator flux rotating frame. Finally, two simulation scenarios are employed to verify the designed controlling structures. In these simulations, the stator voltage and frequency stability for the changes in rotor speed and changes in the local load, has been analyzed.