Rethinking Fault Ride-Through Control of DFIG-Based Wind Turbines From New Perspective of Rotor-Port Impedance Characteristics

To achieve the fault ride through (FRT) operation of DFIG-based wind turbines, various improved control methods have been proposed. However, it is difficult to reveal their essential relations and quantitatively evaluate their performance differences, due to the wide assortment of solving ideas and control structures. To cope with this issue, this paper revisits the FRT control from a new perspective of rotor-port impedance characteristics (RPIC). First, a unified RPIC model of nine typical FRT controls is established and it is found that their RPIC are manifested as the pure inductance, but the inductance values are different in the phase sequence. Subsequently, the influence of RPIC on FRT performance is analyzed and some practical design guidelines for FRT control are given. On this basis, nine typical FRT control methods are quantitatively evaluated and compared in terms of six key performance dimensions. Moreover, the study contributes to the understanding, analysis and redesign of FRT control, and the RPIC perspective features the definite physical meaning and simple. Finally, the analysis is validated by the experiments.