A Grid Synchronization Strategy for Micro-Grid System

A grid-connected synchronization method is very important for distributed energy system. Apart from voltage, frequency and/or sequence requirements, the phase angle can be utilized to vary the power distribution both in the islanded and grid-connected mode. The expected transfer between islanded and grid-connected modes are needed in the operation of renewable energy systems. In this paper, a smooth phaseadjustment algorithm with predictive time based on the droop control is proposed. Some simulation and experimental results are provided to verify the validity of the proposed gridconnected synchronization method.