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In a refrigeration system including an incremental expansion valve and an electronic controller for controlling the operation of the expansion valve, a method of controlling the expansion valve in response to a sensed condition of the refrigerant in the system. According to the method, the valve con

In a refrigeration system including an incremental expansion valve and an electronic controller for controlling the operation of the expansion valve, a method of controlling the expansion valve in response to a sensed condition of the refrigerant in the system. According to the method, the valve controller alters the control gain rate to provide compensation in the valve flow rate for changing refrigerant conditions in the system due to the staging of multiple condenser fans and flooding of the evaporator.

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A method of controlling an incremental electronic expansion valve in a refrigeration system including a controller for operating the expansion valve, a condenser including a number of selectively operable condenser fans, a compressor and an evaporator in closed loop connection with the expansion val

A method of controlling an incremental electronic expansion valve in a refrigeration system including a controller for operating the expansion valve, a condenser including a number of selectively operable condenser fans, a compressor and an evaporator in closed loop connection with the expansion valve, said method comprised of: determining a superheat temperature S of refrigerant; providing an active setpoint Sa at compressor startup; determining a user setpoint Su; modifying said active setpoint Sa to equal said user setpoint Su, said modification being slew rate limited; determining the control error E as the difference between the active setpoint Sa and the superheat temperature S; providing a deadband function Edb of the control error E for limiting the operation of the valve when the control error E is within a predetermined range; determining a first value of an evaporator flooding condition parameter Cf; determining a number of steps Ds to operate said valve, where said number of steps Ds is determined according to a function of an algorithm gain Kp and said deadband function Edb and of said algorithm gain Kp and said flooding condition Cf; limiting said steps Ds to a predetermined limit where the number of steps Ds exceeds said predetermined limit; and operating said valve the number of steps Ds.