POWER SUPPLY APPARATUS, POWER SUPPLY SYSTEM, AND CONTROL METHOD OF POWER SUPPLY APPARATUS

A power supply apparatus of the disclosure is interconnected to the grid together with a power generation apparatus, and configured to control a solar cell and a storage battery. The power supply apparatus includes an inverter for converting DC power from the solar cell and the storage battery into AC power, a first relay for switchover a connection between the inverter and the grid, an AC-DC converter capable of converting AC power from the power generation apparatus into DC power and supplying the DC power to the storage battery during an grid-independent operation, and a controller for controlling such that, at the time of recovery of the grid from the power outage, the AC-DC converter starts operating, that the first relay is switched on, and that the AC-DC converter keeps operating until a reverse power flow to the grid is detected.