Power generating system

A power generating system includes an engine (1), a generator (2), an inverter device (3) interconnected with a commercial power supply (43), and a control device (5) having a phase locked loop circuit (51), which includes an output port (513) connected to a PWM circuit (53) and increases a frequency of a command current (I P ) supplied thereto upon an input of a timing voltage signal (V P ) while the commercial power supply fails, wherein the control device controls the command current to correspond to phase of the timing voltage signal while the inverter device is actuated, fluctuates a phase of the command current by a first variable and calculates a phase difference between the command current and the timing voltage signal, in order to temporarily determine a possibility of the power outage, and then upon a temporal positive conclusion, the control device forcibly fluctuates the phase of the command current by a second variable and conclusively detects the power outage.