Control Parameters Setting Strategy of Converter Used in DFIG Wind Turbine Considering the Small Signal Stability of Power Grid

摘要

With the increasing wind capacity connected to power grid, the stability of power grid is much related to the control parameters of wind turbine (WT) converter. A novel control parameters setting strategy of converter, which used in DFIG WT, considering the small signal stability of power grid is proposed. The dynamic models of DFIG WT system are established. The stator-flux-oriented control strategy is employed in rotor-side converter and the stator-voltage-oriented control scheme is employed in grid-side converter. The 14-order small signal stability analysis model above rated wind speed is established by Lyapunov linearization method. Index of stability margin is introduced to evaluate strength small signal stability of grid, and another stable threshold of real part of eigenvalue that can guarantee small signal stability of system is defined. The parameters setting method of converter is proposed considering the relativity between control parameters and eigenvalues, which maximize the stability margin. Theoretical analysis and simulation results show that the suitable parameters of WT converter can be obtained by the proposed method to maintain the stability of grid.