Air conditioning apparatus

摘要

An air conditioning apparatus using a refrigerating cycle in which a scroll compressor is used to compress a refrigerant. The scroll compressor is driven by an induction motor. The speed of the induction motor is controlled by a PWM type inverter which produces an AC voltage of variable frequency. A carrier frequency higher than 10 KHz is used to effect pulse width modulation of the AC voltage of the inverter, whereby generation of uncomfortable noise is avoided. A control unit is provided to detect slip of the induction motor and to adjust the detached slip to a predetermined optimum value, thereby avoiding excessive lowering of the speed of the motor which may cause lack of lubricating oil for the compressor.