Virtual Inertia and Droop Control Implementation in DFIG-Based Wind Turbines for Frequency Stability Enhancement in Distribution Grids

Abstract

The shift towards renewable energy has led to a substantial increase in wind power integration within electrical grids. However, replacing conventional synchronous generators with Double Fed Induction Generator (DFIG)-based wind turbines presents challenges to system frequency stability. Unlike traditional generators, DFIGs inherently lack natural inertial response due to the decoupling effect of power electronic converters between the rotating mass and grid frequency. This paper introduces and evaluates a control strategy that integrates virtual inertia with droop control directly into the control circuit of the DFIG converters to enhance system stability and provide primary frequency support. The proposed method emulates the inertial response of conventional generators while accounting for the operational constraints of wind turbines by leveraging their existing capabilities, requiring only control modifications and eliminating the need for additional hardware. MATLAB Simulink simulations on a distribution system with wind generation demonstrate that this strategy effectively enhances frequency stability during disturbances such as grid disconnection and wind speed variations, significantly improving key stability metrics, including frequency nadir, rate of change of frequency (RoCoF), and overall frequency response. This approach offers a promising solution to strengthening the frequency stability and resilience of distribution networks with high wind power penetration.