Control Parameters Identification and Its Application to Transient Interaction Analysis of PMSG-Based Wind Farm Connected to Receiving-End Power Grid

High penetration of renewable energy generators such as wind turbines deteriorates transient dynamics of the power system. Unknown model of wind turbines leads to difficult of stability analysis and control of the power system integrated with wind turbines. This paper focuses on control parameters identification of permanent-magnet synchronous generator (PMSG) based wind turbines and using the identified model to analyze the transient dynamics of PMSG-based wind farm connected to the receiving-end power grid. First, the control model of PMSG is generalized with four modules, current limit, reactive power limit, active power controller, and reactive power controller. Since the control parameters of the two limits can be achieved straightforwardly, the main effort is consequently concentrated on the control parameters identification of active/reactive power controller. By clarifying the acquisition of measurable and unmeasurable parameters, a discrete state space model for the two controller is formulated, and the numerical subspace state space system and parameters identification of the active/reactive power controller module. The effectiveness of the proposed control parameters identification was verified with the standard PMSG model based on MATLAB/Simulink. Finally, the identified control model was applied to analyze the transient dynamics of PMSG-based wind farm connected to the receiving-end power grid, and the simulation results on output fluctuation and penetration rate of the wind power impacting on the power grid demonstrate the feasibility of the presented scheme.