Equivalent impedance modeling and control parameters effect analysis of DFIG

Abstract

The doubly-fed induction generator(DFIG) is connected to a series compensation line, and the converter controllers interact with the series compensation line to produce sub-synchronous control interaction(SSCI). In this paper, a method of solving the equivalent resistance modeling of DFIG through a small-signal path is proposed to get the effect of converter control parameters on the damping of DFIG. Firstly, The small signal model is solved by the dynamic equation of DFIG, and the equivalent impedance of the small signal path is obtained. Secondly, the Morris screening method takes the equivalent impedance as the evaluation quantity to screen out the control parameters that have a great impact on damping and the control parameters with coupling effect. Finally, The control parameters have a coupling effect and have different degrees of influence on SSCI through the simulation analysis, so the optimized design of controller parameters can attenuate SSCI of DFIG and reduce the risk.