Apparatus and method for controlling electric compressor

摘要

An electric compressor includes a motor and a compression mechanism that is driven by the motor. The compressor forms part of the refrigerant circuit of an air conditioner. A control apparatus of the compressor adjusts the rotation speed of the motor for controlling the amount of compressed refrigerant gas discharged from the compression mechanism, or the displacement of the compressor, per unit time. When the energy efficiency of the motor is lower than a predetermined level, the control apparatus performs on-off control by alternately turning off the motor. During the on-off control, a required amount of refrigerant gas discharged per unit time is obtained, and the energy efficiency of the motor in the on time is higher than the predetermined level.