| 摘要 |
A protection device for an inverter which is connected to an AC power system, converts DC power into AC power, supplies the AC power to a load and includes a control circuit for detecting a phase and a frequency of an output voltage, for generating a current reference synchronized with the output voltage and for controlling the inverter such that an output current is coincident with the current reference. The protection device includes a first detection circuit for detecting that an AC output is disconnected from the AC power system based on an electrical quantity of the output voltage and for generating a detection signal based on a detection result, and a correction circuit connected to receive the detection signal for generating a correction signal to break a power balance between an output power and a power consumed by the load. The control circuit corrects the current reference by the correction signal and controls the inverter based on the current reference thus corrected thereby to break the power balance. The protection device also includes a second detection circuit for detecting that the power balance is broken and for generating an abnormality signal to stop operation of the inverter based on a detection result. <IMAGE> |
