Abstract: A method and system of providing a power supply to a load (108) using a micro-grid (122) and an electrical grid (102) without interrupting a power supply to the load (108) during a power failure and restoration of the electrical grid (102). A non-grid AC sine wave is synchronized to a grid AC sine wave at the AC to AC synchronization circuit (120) when the electrical grid (102) power supply is restored, without turning OFF the DC to the AC inverter (118) by performing synchronization of the non-grid AC sinewave to match the grid AC sine wave over a number of cycles to make the non-grid AC sine wave compatible with the grid power supply while the power supply generated from the non-grid sources (116) remains uninterrupted and the voltage is in the predetermined threshold range for providing to the load (108).