A Strategy for Mode Transition of Energy Storage Converter

As more and more renewable energy source connected to the grid, ratio of renewable power is becoming higher. So renewable power may provide power for local load in grid when the utility grid malfunctions. To achieve this, renewable power converter or energy storage converter should be able to transit mode between grid-connecting mode and islanding mode seamlessly and smoothly. This paper proposes a method of mode transition that meets the above requirements. The method is based on integral value preloading and voltage pre-synchronization. Effectiveness of proposed method is demonstrated through simulation and experiment.