US Patent 6897370 Power generation apparatus and its control method

In an AC module, if an interconnection relay is provided in an inverter, the inverter increases in size, and disconnection status between the AC module and a system upon occurrence of abnormal condition cannot be easily checked by a user. Accordingly, a plug is connected to an outlet, thereby an output of the inverter is supplied to the system or a load via a coupler. If leakage of direct current, ground fault of a solar cell or the like, a fault or abnormal condition of the inverter, or an abnormal condition of the system is detected, the inverter outputs a signal to separate the plug from the coupler.