Robustness Enhanced control for Grid-Forming PMSG wind farm

Abstract

This paper studies the stability and control of the wind farm utilizing the permanent magnet synchronous generator (PMSG) with grid-forming control based on virtual synchronous generator (VSG) technology. It considers the uncertainties affecting the wind farm’s operation and proposes a robust grid-forming controller to improve stability. Firstly, a state-space model for the PMSG-VSG wind farm is established, incorporating uncertainties of wind speed, grid voltage variations, system control parameters, and short-circuit ratio (SCR) change. Secondly, eigenvalue and participation factor analyses reveal that excessive virtual inertia, insufficient virtual damping, high short-circuit ratios, and varying proportional-integral coefficients in the voltage control can degrade system stability and induce oscillations. Thirdly, a robust grid-forming controller is designed to enhance system stability and robustness in the presence of these uncertainties. The performance of the robust grid-forming controller is validated using an aggregation model of the PMSG-VSG wind farm. Compared with conventional grid-forming controller based on PI controller or additional damping controller, the proposed controller demonstrates superior capability to suppress system oscillations caused by grid voltage disturbances and control parameter uncertainties, thereby improving overall system robustness and stability.