Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology, Ministry of Education (Northeast Electric Power University), Jilin 132012, China

In the scenario of parallel compensation, large-scale wind power grid-connected systems are prone to high-frequency oscillation under the influence of source and grid interaction. The actual impedance network of the power system is complex and the operation conditions are diverse, which limits the applicability of traditional high-frequency oscillation suppression strategies. Therefore, a bi-directional suppression strategy of high-frequency oscillations for a doubly-fed induction generator (DFIG) grid-connected system based on stator voltage feedforward compensation is proposed. Firstly, by constructing an impedance model of the DFIG grid-connected system, the mechanism of high-frequency oscillation is analyzed. Then, the grey relational analysis method is introduced to quantify the dominant factors affecting high-frequency oscillations on both sides of the source and grid. Furthermore, based on the quantified dominant factors, the control loops of the inverters on both sides of the source and grid are reconstructed, and the output impedance of the reshaped inverters is represented in the form of equivalent coefficients. A bi-directional suppression strategy of high-frequency oscillation for the DFIG grid-connected system based on stator voltage feedforward compensation is proposed, effectively improving the output impedance characteristics of the DFIG. Finally, a multi-DFIG grid-connected system and an actual power system model in western China are built in RTLAB-OP5600 for simulation, verifying the accuracy and applicability of the proposed high-frequency oscillation suppression strategy.