The brushless doubly fed induction generator BDFIG) has the potential to be employed as a variable speed wind turbine generator. Owing to brushless configuration of this generator, its reliability is higher than DFIG. Most of the grid faults are unsymmetrical. Hence, this paper analyzes dynamic behavior of BDFIG under symmetrical and unsymmetrical faults and presents dynamic models for both fault types. In order to validate the results of analysis, simulations have been carried out using MATLAB/Simulink software. Then, the control winding CW current is compared under symmetrical and unsymmetrical faults