| 摘要 |
A converter-control device (10) comprises: a voltage-zero-cross detection unit (13) detecting zero cross of the alternate-current voltage and outputting a voltage zero-cross signal; a power-source-current detection unit (12) detecting a power source current of an alternate-current power source (1); a bus-line-voltage detection unit (11) detecting a bus-line voltage across the smoothing capacitor (5); a PWM-signal generation unit (19) generating a PWM-signal for on/off-controlling the switching unit (4), based on the power-source current, the bus-line voltage and a bus-line-voltage command value as a target voltage of the bus-line voltage; a power-source voltage-state detection unit (16) detecting a signal state of the alternate-current voltage based on the voltage zero-cross signal; and a fundamental-switching-frequency selection unit (17) selecting a fundamental switching frequency of the PWM-signal based on the signal state. The unit (19) generates the PWM-signal based on a fundamental switching signal having a fundamental switching frequency selected by the unit (17). |
