A Combined SSR Damping Strategy Based on Virtual Resistance Method and SSR Damping Controller in DFIG-Based Wind Farm

摘要

Due to the special structure of doubly-fed induction generator (DFIG) whose stator connects to the grid directly, Subsynchronous resonance (SSR) is more likely to appear in DFIG-based wind farm connected with series compensated networks. This paper proposes a combined SSR damping strategy based on virtual resistance method and SSR damping controller (SSRDC). The virtual resistance method is used in rotor side converter controller (RSC), and the SSRDC is inserted in grid side converter controller (GSC). The results of eigenvalue analysis show that the damping ratio of SSR mode increases significantly in this way. And the time-domain simulation results also show that the combined SSR damping strategy have a better performance at SSR suppression than only using virtual resistance method or SSRDC. This strategy has great robustness of SSR damping controls and is easy to implement, making it have a broad application prospect.