Expansion valve control
AssigneeCarrier Corporation
InventorTathagata De
Life of this patent
Estimating the term…
Abstract
A method for controlling a refrigeration system having a compressor, heat rejecting heat exchanger, expansion valve and heat absorbing heat exchanger circulating a refrigerant in series flow, the heat absorbing heat exchanger in thermal communication with working fluid, the method includes obtaining an expansion valve position set point; using a feedback control loop to generate a controlled expansion valve position; obtaining a rate of change of an operating parameter of the system; using the rate of change of the operating parameter to generate an adjustment; modifying the controlled expansion valve position using the adjustment; and controlling the expansion valve using the modified controlled expansion valve position.
Claims8
A method for controlling a refrigeration system having a compressor, a heat rejecting heat exchanger, an expansion valve and a heat absorbing heat exchanger circulating a refrigerant in series flow, the heat absorbing heat exchanger in thermal communication with working fluid, the method comprising:
- obtaining an expansion valve position set point;
- obtaining a rate of change of an operating parameter of the system;
- receiving a feed back current controlled expansion valve position;
- determining a difference between the expansion valve position set point and the current controlled expansion valve position from output;
- generating a controlled expansion valve position in response to the difference between the expansion valve position set point and the current controlled expansion valve position from output;
- applying a feed forward gain to the controlled expansion valve position, the feed forward gain determined in response to the rate of change of an operating parameter of the system;
- limiting the controlled expansion valve position;
- using the rate of change of the operating parameter of the system to generate an adjustment;
- modifying the controlled expansion valve position using the adjustment;
- and
- controlling the expansion valve using the modified controlled expansion valve position;
- wherein the operating parameter comprises motor speed of the compressor.
A refrigeration system comprising:
- a compressor;
- a heat rejecting heat exchanger;
- an expansion valve;
- a heat absorbing heat exchanger in thermal communication with working fluid;
- a controller to control the expansion valve, the controller performing operations comprising:
- obtaining an expansion valve position set point;
- obtaining a rate of change of an operating parameter of the system;
- receiving a feed back current controlled expansion valve position;
- determining a difference between the expansion valve position set point and the current controlled expansion valve position from output;
- generating a controlled expansion valve position in response to the difference between the expansion valve position set point and the current controlled expansion valve position from output;
- applying a feed forward gain to the controlled expansion valve position, the feed forward gain determined in response to the rate of change of an operating parameter of the system;
- limiting the controlled expansion valve position;
- using the rate of change of the operating parameter of the system to generate an adjustment;
- modifying the controlled expansion valve position using the adjustment;
- and
- controlling the expansion valve using the modified controlled expansion valve position;
- wherein the operating parameter comprises motor speed of the compressor.
Dependencies are inferred from the claim text.