Impact of grid side converter of DFIG on sub-synchronous oscillation and its damping control

Abstract

Along with the increasing of wind power penetration, the sub-synchronous oscillation phenomena may happen in wind power integrated system. This paper studies the sub-synchronous oscillation phenomena of doubly-fed induction generator (DFIG) based wind farm with series compensation, focuses on the dynamic characteristics of grid side converter control of DFIG and its optimal control. First, this paper analyzes the transfer characteristic of rotor-side and stator-side active power of DFIG, then combining with the analysis of DC capacitor voltage dynamic characteristics, the impacts of control strategy of grid side converter and its parameters on sub-synchronous oscillation behavior are studied. On this basis, a novel additional control strategy to suppress oscillation is proposed in grid side converter. The conclusions are verified by simulation cases of system integrated with DFIG based wind farm by series compensation.