Patent ID: 7784295

Claim:
A method of controlling flow of refrigerant during operation of a refrigeration system to regulate a level of liquid refrigerant in a condenser of the refrigeration system, the method comprising the steps of: generating a liquid level signal corresponding to a level of liquid refrigerant in the condenser of the refrigeration system; generating an error signal using the liquid level signal; generating a rate signal over a predetermined interval using the error signal; selecting a fuzzy logic control algorithm from a plurality of fuzzy logic control algorithms in response to the error signal; generating a control signal to position an adjustable valve in the refrigeration system using the selected fuzzy logic control algorithm, wherein the error signal and the rate signal are inputs to the selected fuzzy logic control algorithm; and controlling the flow of refrigerant in the adjustable valve in response to the control signal to adjust the level of liquid refrigerant in the condenser to a predetermined liquid level.