Paper Title
Robust Synchronization Controller for Reconnection between Microgrid and Utility Power System

This paper is aimed to design a synchronization controller for microgrid, which controls the microgrid to operate in islanding mode and resynchronizes with and reconnects to the power grid. Firstly, it is necessary to estimate the phase angle through the phase-locked loop (PLL) by measuring the three-phase voltage on both sides of the point of common coupling (PCC). Then, the synchronization controller is utilized to reduce the phase difference between grid and microgrid, followed by the requirements in Std. IEEE 1547. Synchronization control is necessary to avoid the unstable situation causing by two non-synchronized systems. The accuracy of the phase detection may be affected by the poor power quality. To overcome the situation such as imbalance, harmonic distortion, dual second order generalized integrator PLL (DSOGI-PLL) is adopted for a basis of synchronization controller. Through the experimental results, the feasibility of the proposed synchronization controller can be verified. Index Terms - Microgrid, resynchronization, DSOGI-PLL, power quality.