Stability analysis of doubly-fed fan with small disturbance oscillation based on regional decoupling impedance model

•Based on the traditional impedance model, a regional decoupling impedance model is constructed to solve the problem of parameter interaction limitations that the traditional impedance model cannot solve.•The Sobol global sensitivity analysis method was employed to evaluate the sensitivity of the regional decoupling impedance model, leading to the identification of the influence ranking of parameters, which quantitatively explains their interaction effects on the mechanism of small interference oscillations.•l Comprehensively considering the stability constraints and the regional decoupling impedance stability criterion enables the identification of a reasonable parameter stability region without the need for extensive parameter testing. This approach facilitates the development of a multi-parameter coordination optimization strategy for the doubly-fed wind system, thus ensuring its stable operation. Because the rotor side converter parameters of doubly-fed fan are not properly set, the doubly-fed wind farm connected to the series complement transmission line may cause small disturbance and oscillation accidents. At present, the analysis and stability analysis between the converter and the series complement parameters are not deep enough. In this paper, the regional decoupling impedance analysis method is proposed to analyze the stability of this phenomenon. Firstly, based on the rotor side control link, the regional decoupling impedance model is constructed to solve the parameter interaction limitation problem that the traditional impedance model cannot solve. Secondly, Sobol global sensitivity analysis is used to analyze the sensitivity of the regional decoupling impedance model, and the influence of the interaction between parameters on the equivalent output resistance is quantitatively analyzed. Then, considering the stability constraints such as DC voltage and average power, the stability domain composed of power, current ratio parameters and series complement parameters of the rotor side converter of the doubly-fed fan is analyzed, and the multi-parameter coordinated optimization strategy is proposed. Finally, the effectiveness of the above method is verified by simulation, which provides a new idea and support for improving the stable operation and reliability of the doubly-fed fan system.