Abstract: An outdoor unit includes: two fan motors that respectively drive two outdoor fans arranged one above the other; a controller including a fan motor power supply capable of separately supplying power to each of the two fan motors connected to two fan motor connectors; and an electrical component temperature sensor that measures temperatures of electrical components. The controller includes a control circuitry that detects which of the two fan motor connectors each of the two fan motors is connected to and supplies power in such a way as to drive the upper one of the outdoor fans based on a result of the detection at the time of single-fan operation. The detection is performed based on comparison between temperatures of the electrical components at the start of the single-fan operation and temperatures of the electrical components after a set time has elapsed since the start of the single-fan operation.

Abstract: A converter control device comprises: a voltage-zero-cross detection unit detecting zero cross of the alternate-current voltage and outputting a voltage zero-cross signal; a power-source-current detection unit detecting a power source current of the alternate-current power source; a bus-line-voltage detection unit detecting a bus-line voltage between terminals of the smoothing capacitor; a PWM-signal generation unit generating a PWM-signal for on/off-controlling the switching unit, 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 detecting a signal state of the alternate-current voltage based on the voltage zero-cross signal; and a fundamental-switching-frequency selection unit selecting a fundamental switching frequency of the PWM-signal based on the signal state of the alternate-current voltage.

Abstract: A converter control device comprises: a voltage-zero-cross detection unit detecting zero cross of the alternate-current voltage and outputting a voltage zero-cross signal; a power-source-current detection unit detecting a power source current of the alternate-current power source; a bus-line-voltage detection unit detecting a bus-line voltage between terminals of the smoothing capacitor; a PWM-signal generation unit generating a PWM-signal for on/off-controlling the switching unit, 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 detecting a signal state of the alternate-current voltage based on the voltage zero-cross signal; and a fundamental-switching-frequency selection unit selecting a fundamental switching frequency of the PWM-signal based on the signal state of the alternate-current voltage.