This paper presents the stability improvement results of a single grid-connected offshore wind turbine (WT) driven permanent magnet synchronous generator (PMSG) system using an energy storage system (ESS) based on a vanadium redox flow battery (VRFB). The VRFB-ESS is connected to the point of common coupling (PCC) of the studied WT-PMSG system through a bidirectional DC/DC converter and a bidirectional DC/AC converter. The stability model of the studied WT-PMSG system is derived first to evaluate the steady-state performance under various operating conditions. The supplementary damping controller (SDC) at the control loop of the bidirectional DC/AC converter of the VRFB-ESS is designed using modal control theory to improve the stability of the studied WT-PMSG system. The dynamic performances of the studied WT-PMSG system with and without the designed SDC are compared to examine the effectiveness of the proposed VRFB-ESS on stability improvement.
Wang et al. (2026) studied this question.