Expansion valve position detection in refrigeration system
AssigneeHill Phoenix, Inc.
InventorsNaresh Kumar Krishnamoorthy, Shobin Balakrishnan
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Abstract
A refrigerated display case having a housing defining a temperature controlled space and a refrigeration system coupled to the housing is provided. The refrigeration system is configured to be operable to affect a temperature of the temperature controlled space. The refrigeration system includes an actuator, a controller, and a sensor. The controller is configured to continuously update a stored position of the actuator based on measurement of an electric current provided to the actuator, retrieve the stored position after a power failure, and restart control based on the stored position of the actuator. The sensor is configured to communicate with the controller.
Claims20
A method of calibrating an expansion valve controller comprising:
- providing a first signal to an actuator;
- detecting an electrical current supplied to the actuator;
- storing a value of the electrical current to a non-volatile memory;
- determining a first position of the actuator based on the electrical current;
- detecting a magnitude change in the electrical current provided to the actuator by detecting that the electrical current is increasing;
- detecting at least one spike in the electrical current;
- storing the at least one spike in the non-volatile memory;
- determining that the electrical current is decreasing to a first threshold;
- determining, based on the at least one spike, that the actuator is in a second position of a plurality of discrete positions;
- and
- storing the second position in the non-volatile memory.
An apparatus comprising a non-transitory computer readable medium configured to store instructions executable by at least one hardware processors to perform operations for calibrating an expansion valve controller, the operations comprising:
- providing a first signal to an actuator;
- detecting an electrical current supplied to the actuator;
- storing a value of the electrical current to a non-volatile memory;
- determining a first position of the actuator based on the electrical current;
- detecting a magnitude change in the electrical current provided to the actuator by detecting that the electrical current is increasing;
- detecting at least one spike in the electrical current;
- storing the at least one spike in the non-volatile memory;
- determining that the electrical current is decreasing to a first threshold;
- determining, based on the at least one spike, that the actuator is in a second position of a plurality of discrete positions;
- and
- storing the second position in the non-volatile memory.
Dependencies are inferred from the claim text.