Stochastic Stability Assessment of Grid Connected DFIG System

This paper assesses the dynamic performance of grid-connected Doubly Fed Induction Generators (DFIGs) under stochastic wind speed. The detailed full-order dynamic model of the DFIG is exploited. The wind speed is modelled by a stochastic differential equation (SDE). A stochastic-calculus-based approach, which avoids the use of tedious time domain simulations, is used to determine the statistical variance of the DFIG variables for the stochastic variations of wind speed. The results are validated using time-domain simulations and the modal analysis for the grid-connected DFIG system. Moreover, the impact of system parameters (such as the controller gains and grid impedance) on the steady-state variance of the DFIG variables is also assessed.