Air conditioner with plurality of indoor units and its control method

The present invention discloses a one-to-many air-conditioner and its control method. Wherein, a compressor control method of an outdoor machine comprises a diode rectifying circuit to rectify AC electricity into DC electricity, a transducer to convert a rectified DC voltage into a three-phase AC voltage according to a PWM signal and output the three-phase AC voltage to a motor and a controller to compensate the PWM signal imposed to the transducer to control the transducer. The air-conditioner is additionally composed of a current sensor to detect transducer output current and a frequency calculator to calculate frequency of an output current detected by the current sensor. Wherein, the controller compares a specific command value fn with a calculated frequency fc and controls operating state of the transducer according to the comparison. The present invention has the benefits of correctly working out a voltage frequency to drive the motor without a high-power filter capacitor, thus accurately controlling op