Abstract: A motor drive device includes a single-phase inverter that converts a direct-current voltage into an alternating-current voltage applied to a motor. The motor drive device includes a control power supply outputting power having a voltage lower than the direct-current voltage. The motor drive device includes a drive signal generation unit driven by the power. The drive signal generation unit generates drive signals driving switching elements of the inverter. The motor drive device includes a power supply switch operating so as to allow supply of the power from the control power supply to the drive signal generation unit when a rotation speed of the motor is higher than a threshold. The power supply switch operates so as to stop the supply of the power from the control power supply to the drive signal generation unit when the rotation speed is lower than the threshold.

Abstract: A motor drive device includes a single-phase inverter which is an inverter including a plurality of switching elements. The inverter converts a direct-current voltage output from a direct-current power supply into an alternating-current voltage, by operation of the plurality of switching elements operating, and applies the alternating-current voltage to a motor. The motor drive device includes a control power supply outputting power having a voltage lower than the direct-current voltage, by using the direct-current voltage. The motor drive device includes a drive signal generation unit driven by the power. The drive signal generation unit generates drive signals driving the plurality of switching elements, and outputs the generated drive signals to the plurality of switching elements. The motor drive device includes a power supply switch operating so as to allow supply of the power from the control power supply to the drive signal generation unit when a rotation speed of the motor is higher than a threshold.