Research on SCESS-DFIG DC bus voltage fluctuation suppression strategy for frequency inertia regulation of power grid

Abstract

The doubly fed induction generator with super capacitor is helpful to enhance the system inertia. At the same time, its structural characteristics are more suitable for the power grid topology without communication lines. However, the change of its topology also brings some problems. In this article, when SCESS-DFIG is participating in frequency regulation, DC bus voltage fluctuation caused by power imbalance of multiple converters is studied. The dynamic power response of super capacitor with DC-DC converter is a step load for grid side converter. The load of DC bus is nonlinear and random, so the balance and stability of the original system will change accordingly. Because of the complex topology and system composition of the doubly fed induction generator with super capacitor, the conventional feed-forward compensation control strategy can not be used to improve its dynamic response speed. Therefore, this article designs a control strategy which is applied for DC bus voltage fluctuation of the doubly fed induction generator with super capacitor. The theory proposed in this article is verified by simulation model and experiment.