Inertia Provision of DFIG-Based Wind Turbines by Improving the Damping Ratio of PLL

Due to the rapid control of power electronics, it results that the wind turbines (WTs) typified by double-fed induction generator (DFIG) based WTs do not have inertia response capability. Many inertia control methods have been proposed, but they suffer from large structural modifications, high cost, poor adaptability, and slow response. In this regard, this paper first analyzes the inertia response characteristics of DFIG-based WT and further reveals principle of achieving power response of WTs from controlling the phase-locked angle. Then, why the WTs have no inertia response capacity is analyzed when a typical phase-locked loop (PLL) is adopted. Based on this, an inertia response strategy of DFIG-Based WTs by improving the damping ratio of PLL is put forward, and frequency domain response characteristic of it is compared and analyzed with those of typical PLL. Finally, a simulation system of synchronous generator (SG) and an aggregated WT farm is built in MATLAB/Simulink for verification.