Compressor diagnostic and protection system and method

• US 7,905,098 B2
• Filed: 04/04/2005
• Issued: 03/15/2011
• Est. Priority Date: 04/27/2004
• Status: Active Grant

• Current Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Original Assignee: Emerson Climate Technologies Incorporated (Emerson Electric Company)
• Inventors: Pham, Hung M.
• Primary Examiner(s): Ali; Mohammad M
• Application Number:
  US11/098,575
• Publication Number:
  US 20050235661A1
• Time in Patent Office: 2,171 Days
• Field of Search: 621/26, 621/27, 621/29, 622/283, 622/30, 621/25, 622/25, 622/27, 621/83, 236/94, 361/22, 361/23, 361/31, 318/445
• US Class Current: 62/126
• CPC Class Codes: B23P 15/26 heat exchangers or the like making heat exchangers by methods covered by other subclasses B21D53/02
• CPC Class Codes: F04C 2270/18 Pressure
• CPC Class Codes: F04C 2270/19 Temperature
• CPC Class Codes: F04C 2270/80 Diagnostics
• CPC Class Codes: F04C 28/00 Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
• CPC Class Codes: F25B 1/04 with compressor of rotary type F25B1/005, F25B1/10 take precedence
• CPC Class Codes: F25B 2500/06 Damage
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2700/151 of the compressor motor
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/1933 Suction pressures
• CPC Class Codes: F25B 2700/2106 of fresh outdoor air
• CPC Class Codes: F25B 2700/21151 at the suction side of the compressor
• CPC Class Codes: F25B 2700/21152 at the discharge side of the compressor
• CPC Class Codes: F25B 2700/2116 of a condenser
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence
• CPC Class Codes: F25D 2400/36 Visual displays
• CPC Class Codes: Y10T 29/49353 Heat pipe device making

Abstract

A system and method includes a compressor operable in a refrigeration circuit and including a motor, a current sensor providing a high-side signal indicative of an operating condition of a high-pressure side of the refrigeration circuit, a discharge line temperature sensor providing a low-side signal indicative of an operating condition of a low-pressure side of the refrigeration circuit, and processing circuitry processing the high-side signal and the low-side signal to indirectly determine a non-measured operating parameter of the refrigeration circuit.

Claims

1. A system comprising:

a compressor operable in a refrigeration circuit and including a motor;

a current sensor providing a high-side signal indicative of an operating condition of a high-pressure side of the refrigeration circuit;

a discharge temperature sensor providing a low-side signal indicative of an operating condition of a low-pressure side of the refrigeration circuit; and

processing circuitry processing said high-side signal and said low-side signal to determine at least one of a non-measured condenser temperature and a non-measured evaporator temperature of the refrigeration circuit.

2. The system of claim 1, wherein said processing circuitry determines at least one of a suction superheat and a discharge superheat.

3. The system of claim 1, wherein said condenser temperature is a function of current.

4. The system of claim 1, wherein said evaporator temperature is a function of said condenser temperature and discharge temperature.

5. The system of claim 2, wherein said discharge superheat is a function of said condenser temperature and discharge temperature.

6. The system of claim 2, wherein said suction superheat is a function of said discharge superheat.

7. The system of claim 2, wherein said processing circuitry is operable to detect a floodback condition based on a comparison of discharge superheat temperature to a predetermined discharge superheat temperature.

8. The system of claim 7, wherein said predetermined discharge superheat is approximately equal to forty degrees Fahrenheit or less.

9. The system of claim 1, further comprising a system controller in communication with said processing circuitry.

10. The system of claim 9, wherein said system controller receives said high-side signal and said low-side signal and is operable to verify at least one of said condenser temperature and said evaporator temperature determined by said processing circuitry.

11. The system of claim 9, wherein said system controller includes at least one hand-held computer.

12. The system of claim 11, wherein said hand-held computer is at least one of a personal data assistant and a cellular telephone.

13. The system of claim 2, wherein said processing circuitry stores at least one of an equation and a constant for use in processing said high-side signal and said low-side signal.

14. The system of claim 2, wherein said processing circuitry stores at least one of a relationship between compressor power and condenser temperature and between discharge temperature and evaporator temperature.

15. The system of claim 1, wherein said processing circuitry references said high-side signal on a first relationship between compressor power and condenser temperature to determine said non-measured condenser temperature.

16. The system of claim 15, wherein said processing circuitry references said non-measured condenser temperature on a second relationship between discharge temperature and evaporator temperature to determine said non-measured evaporator temperature.

17. The system of claim 15, wherein said first relationship includes a plot of estimated evaporator temperature, said processing circuitry referencing said high-side signal on said first relationship to determine said non-measured condenser temperature based on said estimated evaporator temperature.

18. The system of claim 17, wherein said plot of estimated evaporator temperature includes multiple plots of estimated evaporator temperatures.

19. The system of claim 15, wherein said first relationship is a function defined by at least a compressor-specific constant, a compressor-specific coefficient of a variable condenser temperature, and a given approximate evaporator temperature.

20. The system of claim 19, wherein said first relationship is:

P=C0+(C1*T_cond)+(C2*T_evap)+(C3*T_cond^2)+(C4*T_cond*T_evap)+(C5*T_evap^2)+(C6*T_cond^3)+(C7*T_evap*T_cond^2)+(C8*T_cond*T_evap^2)+(C9*T_evap^3),

where P is compressor power determined based on said high-side signal and a voltage supplied to said compressor, C0-C9 are compressor-specific constants, T_cond is said non-measured condenser temperature, and T_evap is said given approximate evaporator temperature.

21. A method comprising:

generating a high-side signal indicative of high-pressure operating conditions at a compressor in a refrigeration circuit based on a current measurement of a current sensor;

generating a low-side signal indicative of low-pressure operating conditions at said compressor in said refrigeration circuit based on a temperature measurement of a discharge temperature sensor;

processing said high-side signal and said low-side signal;

calculating at least one of a non-measured condenser temperature and a non-measured evaporator temperature based on said high-side signal and said low-side signal; and

diagnosing said refrigeration circuit based on said at least one of said condenser temperature and said evaporator temperature.

22. The method of claim 21, further comprising determining a discharge superheat and a suction superheat based on said high-side signal and said low-side signal to diagnose said refrigeration circuit.

23. The method of claim 22, wherein said calculating includes referencing at least one of an equation and a constant loaded into processing circuitry of said refrigeration circuitry.

24. The method of claim 22, wherein said calculating includes referencing at least one of a relationship between compressor power and condenser temperature and a relationship between discharge temperature and evaporator temperature.

25. The method of claim 22, further comprising communicating at least one of said condenser temperature, said evaporator temperature, said discharge superheat, and said suction superheat to a system controller.

26. The method of claim 25, further comprising verifying at least one of said condenser temperature, said evaporator temperature, said discharge superheat, and said suction superheat at said system controller.

27. The method of claim 26, wherein said verifying includes calculating at least one of said condenser temperature, said evaporator temperature, said discharge superheat, and said suction superheat based on said high-side signal and said low-side signal communicated to said system controller by said processing circuitry.

28. The method of claim 26, wherein said verifying includes calculating at least one of said condenser temperature, said evaporator temperature, said discharge superheat, and said suction superheat based on said high-side signal and said low-side signal detected by said system controller.

29. The method of claim 21, further comprising calculating a condenser temperature difference including deriving an ambient temperature and subtracting said ambient temperature from said condenser temperature.

30. The method of claim 21, wherein said calculating said non-measured condenser temperature includes referencing said high-side signal on a first relationship between compressor power and condenser temperature.

31. The method of claim 30, wherein said calculating said non-measured evaporator temperature includes referencing said low-side signal and said calculated non-measured condenser temperature on a second relationship between discharge temperature and evaporator temperature.

32. The method of claim 30, wherein said first relationship is a function defined by at least a compressor-specific constant, a compressor-specific coefficient of a variable condenser temperature, and a given approximate evaporator temperature.

33. The method of claim 32, wherein said first relationship is:

P=C0+(C1*T_cond)+(C2*T_evap)+(C3*T_cond^2)+(C4*T_cond*T_evap)+(C5*T_evap^2)+(C6*T_cond^3)+(C7*T_evap*T_cond^2)+(C8*T_cond*T_evap^2)+(C9*T_evap^3),

where P is compressor power determined based on said high-side signal and a voltage applied to said compressor, C0-C9 are compressor-specific constants, T_cond is said non-measured condenser temperature, and T_evap is said given approximate evaporator temperature.