An Improved Control Strategy Based on Unified Impedance Model of DFIG under Weak Grid

摘要

This paper proposes a grid voltage disturbance compensation control to improve the stability of the DFIG system under weak grid condition. A detailed impedance model of the DFIG system is developed in the d-q frame. Based on the proposed model, the relationship between the outputs of the controllers and the grid voltage disturbance at PCC can be obtained. Then, the compensation control of the grid voltage disturbance are integrated to the current control loops of RSC and GSC to improve the stability of the DFIG system connected to the weak grid. In this paper, the effective of the proposed compensation control is proved through the GNC, which illustrates that the compensation control implemented in RSC and GSC simultaneously has a better ability to maintain the stability of the DFIG system under weak grid condition than the only one side used. The simulation results verify the analysis.