To prevent a compressor motor from reverse rotation caused by the pressure difference of coolant when the compressor motor is stopped, and avoid abnormal sound of the compressor motor.
The control device of a compressor motor for an air conditioner has an inverter device 11 which is composed of a plurality of switching devices and to which the compressor motor 13 is connected, and a controller 14 which controls on/off of the switching devices of the inverter device 11 to control the compressor motor 13. The controller 14 has a zero vector current applying means which applies currents to all the switching devices on the positive voltage side or on the negative voltage side of the inverter device 11, a DC excitation current applying means which applies currents to one switching device on the positive voltage side and to one switching device on the negative voltage side, and a braking means which obstructs reverse rotation which makes the zero vector current applying means or the DC excitation current applying means operate after the operation of the compressor motor is stopped.
MIYAZAKI HIROSHI
KANBE TAKAYUKI
