For Double Fed Induction Generator (DFIG) in islanded system, a design is proposed which adds Energy Storage System (ESS) in the direct current side of the back- to-back converter and changes the capacity of the load side converter. The generator-side converter of the system uses the power decoupling control strategy to achieve maximum power tracking. The load-side converter uses the constant voltage and frequency control strategy to achieve the constancy of voltage and frequency in islanded system. When switched to grid-connected mode, the phase synchronization control strategy based on frequency disturbance is applied to achieve the rapid phase synchronization of the grid and the islanded system. A simulation model is build and the results shows the effectiveness of the control strategy for the stable operation of islanded sys-tem and the rapid phase synchronization when the system is connected to the grid.
