Influence of DFIG controller parameter on SSR under all operation areas

On the subsynchronous resonance (SSR) problem in doubly fed induction generator (DFIG) based wind farm transmission system, it is unilateral to research under the condition that DFIG runs in maximum power point tracking (MPPT) mode. This paper studies SSR characteristics under whole operation area, including MPPT. SSR stable area is proposed by scanning eigenvalues under various rotor speed and output power. Then, influence on stable area by various converter controller parameters is analyzed. Result shows that SSR risk increases as either wind speed or output power decreases. Inner current loop gain of rotor side converter has a negative impact on SSR stability, that is the smaller the gain is, the bigger the stable area is. But too small gain will lead to bad tracing result of current, which is the control dead zone. In the end, suggestions on DFIG controller parameter and wind farm safe operation are given.