| 摘要 |
A power converter having an ac side connected through a reactor to an ac power source and a dc side connected to a smoothing capacitor and a load, the converter being capable of converting and inverting electric power in accordance with the pulse width modulation control, characterized by comprising: a voltage detection circuit for detecting a voltage on the side of the ac power source when viewed from the reactor; a first judgement section for detecting that the amplitude of a voltage component on the ac side of the power converter, which is included in the ac power source voltage, is above a predetermined value on the basis of an output signal from the voltage detection circuit to produce a signal indicative of the judgement result; a second judgement section for detecting that the amplitude of the ac power source voltage is below the predetermined value to produce a signal indicative of the judgement result; and a gate circuit for performing logical sum of the outputs from the first and second judgement sections to use an output signal from the gate circuit as a detection signal indicative of a power interruption of the ac power source.
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