Control unit for a refrigerant compressor

A refrigerant compressor for refrigeration plants, comprising:

• a compressor unit driven by a drive unit, wherein the compressor and drive units fare provided with a control unit which is controllable by means of a delivery rate control system in order to control the refrigerant compressor at different delivery rates, and wherein an external delivery rate setpoint value is communicated to the delivery rate control system;
• wherein the delivery rate control system is configured to acquire, by means of a sensor, a compressor reference temperature of the compressor unit, the delivery rate control system being configured to ascertain an operating state value group for acquisition of an operating state of the refrigerant compressor;
• wherein the delivery rate control system is configured to ascertain the operating state value group based upon both the acquired compressor reference temperature and the delivery rate;
• wherein the delivery rate control system uses specified reference values to differentiate between critical and non-critical operating states of the refrigerant compressor;
• and
• wherein, if at least one value of the ascertained operating state value group, based upon the compressor reference temperature, permits a critical operating state of the refrigerant compressor, the delivery rate control system specifies a delivery rate to operate the refrigerant compressor outside of the critical operating state.