Compressor unit, refrigeration circuit comprising the same and method of operating a compressor unit

Abstract

A compressor unit () for use in a refrigeration circuit, comprises at least two compressors (); and a common variable frequency drive (), configured to be connected to a three phase grid voltage supply (); each compressor () having an inlet port () configured to be in refrigerant communication, via a suction line, with an outlet of an evaporator; an outlet port () configured to be in refrigerant communication, via a pressure line, to an inlet of a condenser; a compressor motor (), particularly an alternating current induction motor, with a three phase supply line (--); a power modulation means () for controlling the power of the compressor () according to its load needs; wherein each compressor () is switchable, independently from the respective other compressor(s) (), to be connected, during start-up and acceleration of the respective compressor (), to the common variable frequency drive (), and to be connected, during rated-speed operation of the respective compressor (), to a common three phase grid voltage supply ().