A new self-synchronization control strategy for grid interface inverters with local loads

The Microgrid voltage may deviate from the grid voltage when it operates in islanded mode, which will result in unexpected large inrush currents during the re-connection process. This paper proposed a new self-synchronization control strategy for synchronverter with local loads which utilizes the reference phase angle of synchronverter as the reference angle in the rotating frame. A compensation quantity for the reference angle and frequency of synchronverter can be obtained by a PI control unit and then provided to the virtual synchronous control unit. Synchronization will be implemented automatically with the regulation of the compensation quantity. Simulation and experimental results demonstrate that the inrush current during the reconnection process has been restrained and seamless transfer from island mode to grid-connected mode can be achieved.