REFRIGERATION CYCLE CONTROL APPARATUS

A refrigeration cycle or an air conditioner including a refrigeration cycle is subjected to feedback control based on modern control theory. An apparatus controlling a controlled object, that is, the refrigeration cycle of the air conditioner including the refrigeration cycle, is formed as an optimal regulator. A controlled input to the controlled object includes a capacity of a compressor or a degree of opening of an expansion valve. A control output from the controlled object includes a temperature of air at a point downstream of the evaporator or a superheat of refrigerant. Feedback gains are predetermined by use of dynamic models constructed for respective steady operation states of the controlled object.