Enhancing DC-Link Voltage Control of a DFIG Driven by a Wind Turbine Integrated with a STATCOM

The growing penetration of wind power into modern electrical grids has intensified the need for advanced reactive power compensation and DC-link voltage regulation techniques to ensure compliance with increasingly stringent grid code requirements. Therefore, this paper introduces a reactive power control enhancement of a static synchronous compensator (STATCOM) for a grid-connected doubly fed induction generator (DFIG) driven by a variable-speed wind turbine (VSWT) during abnormal events. The effects of all grid faults can lead to voltage instability or even to the DFIG’s disconnection from the grid, especially if the DFIG cannot actively provide reactive power support to the grid. Therefore, the proposed cascaded FOPI-PI controller for a STATCOM is integrated with the grid and is employed in DC-link voltage control of the grid-side converter of the DFIG. This FOPI-PI controller for the STATCOM can rapidly inject reactive power to best maintain the wind turbine DFIG’s connectivity, minimize power loss, and considerably improve the voltage profile at the point of common coupling (PCC) during abnormal events reported in the literature. Furthermore, a growth optimization algorithm (GOA) technique to optimize the PI control parameters of the STATCOM scheme is compared with that of a cascaded FOPI-PI controller tuned by GOA for the STATCOM scheme. To test the validity of the proposed control method, various simulations in MATLAB, such as voltage sags, symmetrical grid faults, and asymmetrical faults, are investigated.