Smooth synchronization method for the reconnection of islanded microgrids

In the context of a microgrid, one of the challenges to be faced is the process of reconnection to the main grid after the islanding operation, making a previous synchronization between the point of common coupling and the grid's voltage necessary. In this paper, a control method is proposed in order to allow a smooth synchronization before the reconnection, minimizing transients that could affect the operation of sensible loads. The implementation of the algorithm was made in the TMS320F28377S microcontroller and tests were made through hardware-in-the-loop simulations, comparing firstly the proposed method and a non smooth synchronization one, showing the importance of a proper control, validating the proposal. Next, comparisons were made between the performances of the proposed method and the existing ones in the literature, pointing out their advantages and disadvantages.