Mode switching method for switching micro power grid from islanding mode to grid-connected mode

The invention provides a mode switching method of a micro power grid from an islanding mode to a grid-connected mode. The mode switching method comprises the steps of: stopping operation of all distributive power supplies in the micro power grid; cutting off all switches of operating loads in the micro power grid; closing a grid-connected switch; closing all switches of loads when the bus voltage of the micro power grid is greater than a predetermined voltage; respectively feeding an energy storage distributive power supply, a photovoltaic distributive power supply and a fan distributive power supply and enabling the distributive power supplies to work in a control mode that output active power and inactive power equal to a reference power. A mode switching safe terminating mechanism is additionally arranged to better protect equipment. All the distributive power supplies are ensured to stop operating, thus asynchronous grid-connected problem cannot happen, and the grid-connected impact current is reduced to the minimum extent.