IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
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출원번호 |
US-0091705
(2011-04-21)
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등록번호 |
US-10254026
(2019-04-09)
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발명자
/ 주소 |
- Patel, Tejendra
- Ernst, Jeffrey
- Schroder, Bruce R.
- DeRoy, Robert M.
- Coussey, Kokjovi
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출원인 / 주소 |
- Hamilton Sundstrand Corporation
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
0 인용 특허 :
7 |
초록
▼
An electronic expansion valve (EEV) is employed in refrigeration systems to regulate the flow of refrigerant through an evaporator. The position of the EEV is controlled through a first control loop that generates a first position signal based on superheat feedback associated with the refrigeration
An electronic expansion valve (EEV) is employed in refrigeration systems to regulate the flow of refrigerant through an evaporator. The position of the EEV is controlled through a first control loop that generates a first position signal based on superheat feedback associated with the refrigeration system, and a second control loop that generates a second position signal based on pressure feedback associated with the refrigeration system. The larger of the first position signal and the second position signal is selected to control the position of the EEV value, and the selected position signal is provided in feedback to both the first control loop and the second control loop.
대표청구항
▼
1. A method of controlling position of an electronic expansion valve (EEV) employed in a refrigeration system, the method comprising: generating, by a processing unit, a first EEV position control signal based on superheat feedback associated with the refrigeration system in a first control loop;gen
1. A method of controlling position of an electronic expansion valve (EEV) employed in a refrigeration system, the method comprising: generating, by a processing unit, a first EEV position control signal based on superheat feedback associated with the refrigeration system in a first control loop;generating, by the processing unit, a second EEV position control signal based on pressure feedback associated with the refrigeration system in a second control loop;comparing, by the processing unit, the first EEV position control signal and the second EEV position control signal;selecting, by the processing unit based on the comparison of the first EEV position control signal and the second EEV position control signal, either the first EEV position control signal or the second EEV position control signal as a selected position control signal employed to control position of the EEV;providing, by the processing unit, the selected position control signal in feedback to both the first control loop and the second control loop;outputting, by the processing unit, the selected position control signal to modify a position of the EEV; andmodifying, based on the outputted selected position control signal, the position of the EEV. 2. The method of claim 1, wherein selecting either the first EEV position control signal or the second EEV position control signal based on the comparison of the first EEV position control signal and the second EEV position control signal includes selecting the one of the first EEV position control signal and the second EEV position control signal corresponding to a most closed position of the EEV. 3. The method of claim 1, wherein generating the first EEV position control signal includes: calculating a superheat value based on a monitored pressure and a monitored temperature associated with the refrigeration system;comparing the calculated superheat value to a reference superheat value to generate a superheat error value; andapplying the superheat error value to a first proportional-integral controller to generate the first EEV position control signal. 4. The method of claim 3, wherein the selected position control signal is provided in feedback to reset an integrator value of the first proportional-integral controller. 5. The method of claim 3, wherein the first proportional-integral controller employs a non-linear gain function, wherein the first proportional-integral controller employs a larger gain value when the calculated superheat value is less than the reference superheat value, and a smaller gain value when the calculated superheat value is greater than the reference superheat value. 6. The method of claim 3, wherein the first proportional-integral controller receives feed-forward input regarding compressor speed to be included in calculation of the first EEV position control signal. 7. The method of claim 1, wherein generating the second EEV position control signal includes: comparing a monitored pressure associated with the refrigeration system to a maximum operating pressure (MOP) reference to generate a MOP error value; andapplying the MOP error value to a second proportional-integral controller to generate the second EEV position control signal. 8. The method of claim 7, wherein the selected position control signal is provided in feedback to reset an integrator value of the second proportional-integral controller. 9. The method of claim 1, wherein outputting the selected position control signal to modify the position of the EEV further includes: calculating a valve position command signal by comparing the selected position control signal to a current valve position signal; andupdating the current valve position signal based on the valve position command signal. 10. A controller system for controlling position of an electronic expansion valve (EEV) included in a refrigeration system, the controller system comprising: an EEV motor controller that commands the EEV to a desired position; anda processing unit that receives feedback regarding monitored pressure and temperature within the refrigeration system, the processing unit executing a superheat (SH) control loop that calculates a first EEV position control signal based on superheat feedback calculated based on the monitored pressure and temperature, the processing unit executing a maximum operating pressure (MOP) control loop that calculates a second EEV position control signal based on the monitored pressure of the refrigeration system, wherein the processing unit compares the first EEV position control signal and the second EEV position control signal and selects, based on the comparison of the first EEV position control signal and the second EEV position control signal, either the first EEV position control signal or the second EEV position control signal as a selected position control signal employed to control position of the EEV and provides the selected position control signal as feedback to both the SH control loop and the MOP control loop. 11. The controller system of claim 10, wherein the processing unit selects, based on the comparison of the first EEV position control signal and the second EEV position control signal, the one of the first EEV position control signal and the second EEV position control signal corresponding to a most closed position of the EEV as the position control signal employed to control position of the EEV. 12. The controller system of claim 10, wherein the SH control loop compares the superheat feedback to a desired superheat value to create a superheat error signal, the SH control loop including a first proportional-integral (P-I) controller that generates the first EEV position control signal based on the superheat error signal and the selected position control signal provided as feedback to both the SH control loop and the MOP control loop. 13. The controller system of claim 12, wherein the first P-I controller implements non-linear gain functionality, wherein the first P-I controller employs a larger gain value when the calculated superheat value is less than the reference superheat value, and a smaller gain value when the calculated superheat value is greater than the reference superheat value. 14. The controller system of claim 12, wherein the first P-I controller receives feed-forward speed inputs associated with speed of a compressor included as part of the refrigeration system, wherein the first EEV position control signal provided by the first P-I controller takes into account the effect compressor speed has on the superheat feedback. 15. The controller system of claim 10, wherein the MOP control loop compares the monitored pressure to a maximum operating pressure (MOP) reference value to create an MOP error signal, the MOP control loop including a second proportional-integral (P-I) controller that generates the second EEV position control signal based on the MOP error signal and the selected position control signal provided as feedback to both the SH control loop and the MOP control loop. 16. The controller system of claim 10, wherein the processing unit further includes an EEV delta step calculator that compares the selected position control signal to a current valve position signal to generate a valve command signal, and updates the current valve position signal based on the generated valve command signal. 17. A system comprising: an evaporator for providing cooling to a medium based on evaporation of a refrigerant flowing through the evaporator;an electronic expansion valve (EEV) selectively opened and closed to regulate the flow of refrigerant through the evaporator; anda processing unit for regulating the flow of refrigerant through the evaporator through selective control of the opening and closing of the EEV, the processing unit executing a superheat (SH) control loop that calculates a first EEV position control signal based on superheat feedback calculated based on monitored pressure and temperature, the processing unit executing a maximum operating pressure (MOP) control loop that calculates a second EEV position control signal based on the monitored pressure, wherein the processing unit compares the first EEV position control signal and the second EEV position control signal and selects, based on the comparison of the first EEV position control signal and the second EEV position control signal, either the first EEV position control signal or the second EEV position control signal as a selected position control signal employed to control position of the EEV and provides the selected position control signal as feedback to both the SH control loop and the MOP control loop. 18. The system of claim 17, wherein the SH control loop compares the superheat feedback to a desired superheat value to create a superheat error signal, the SH control loop including a first proportional-integral (P-I) controller that generates the first EEV position control signal based on the superheat error signal and the selected position control signal provided as feedback to both the SH control loop and the MOP control loop. 19. The system of claim 18, wherein the first P-I controller implements non-linear gain functionality, wherein the first P-I controller employs a larger gain value when the calculated superheat value is less than a reference superheat value, and a smaller gain value when the calculated superheat value is greater than the reference superheat value. 20. The system of claim 18, wherein the first P-I controller receives feed-forward speed inputs associated with speed of a compressor included as part of the system, wherein the first EEV position control signal provided by the first P-I controller takes into account the effect compressor speed has on the superheat feedback. 21. The system of claim 17, wherein the MOP control loop compares the monitored pressure to a maximum operating pressure (MOP) reference value to create an MOP error signal, the MOP control loop including a second proportional-integral (P-I) controller that generates the second EEV position control signal based on the MOP error signal and the selected position control signal provided as feedback to both the SH control loop and the MOP control loop. 22. The system of claim 17, wherein the processing unit further includes an EEV delta step calculator that compares the selected position control signal to a current valve position signal to generate a valve command signal, and updates the current valve position signal based on the generated valve command signal. 23. The system of claim 17, wherein the processing unit selects the one of the first EEV position control signal and the second EEV position control signal corresponding to a most closed position of the EEV as the position control signal employed to control position of the EEV.
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