Novel Subsynchronous Resonance Mitigation Scheme by Stator Side Converter in DFIG

In this paper, a new additional damping control strategy is proposed to suppress the subsynchronous oscillation based on the stator side converter of doubly-fed induction generator. Firstly, analyzed from the mechanism of the second synchronous oscillation of DFIG, the torque change caused by the change of the rotational speed of the wind machine is divided into two parts, the rotor variation and the stator variation. And an additional torque reversing with the rotational speed increment is generated by introducing additional control in the stator side converter control strategy, which presents a positive damping for the system. Then, the inhibition effects with and without the additional damping control are compared by PSCAD/EMTDC time-domain simulation. The results show that the control of subsynchronous oscillation by fan itself has a good corresponding speed and inhibition effect. The proposed damping strategy has a strong engineering value and practical significance.