| 摘要 |
An islanding detection device using an automatic phase-shift method is provided to detect the islanding by converging or diverging the frequency of the voltage at a point of the common coupling. An islanding detection device using an automatic phase-shift method includes a PWM(Pulse Width Modulation) unit, a voltage controller(36), a current controller(34), a sine wavel unit(38), and a PLL(Phase Locked Loop)(60). The PWM unit varies a pulse width according to a magnitude of a sine wave, and delivers the pulse width to an inverter. The voltage controller controls an input terminal voltage of an inverter of a power distribution system at a constant value. The current controller controls an output terminal current of the inverter of the power distribution system at a constant value. The sine wave unit generates a sine wave, which is in-phase with an output current reference value of the power distribution system. The PLL detects the inverter output current and controls the inverter output current to be in-phase with a coupling voltage.
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