Stability Analysis and Robustness Enhanced Control for Grid-Forming Pmsg Wind Farm

Abstract

This paper analyzes the stability of the wind farm using a permanent magnet synchronous generator (PMSG) and grid-forming control based on virtual synchronous generator (VSG) technology. The impact of uncertainties on the wind farm's stability is examined, and a robust grid-forming controller is designed to enhance 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 control based on PI, 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.

Keywords: Wind power, Permanent Magnet Synchronous Generator (PMSG), grid-forming, VSG, Uncertainty