Distributed intelligence control for commercial refrigeration

• US 6,332,327 B1
• Filed: 03/14/2000
• Issued: 12/25/2001
• Est. Priority Date: 03/14/2000
• Status: Expired due to Term

• Current Assignee: Hussmann Corporation (Panasonic Holdings Corporation)
• Original Assignee: Hussmann Corporation (Panasonic Holdings Corporation)
• Inventors: Thomas, Charles D., Street, Norman E., Sunderland, Ted W., Shapiro, Doron, DʼAnna, Michael J.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US09/524,939
• Time in Patent Office: 651 Days
• Field of Search: 621/25, 621/26, 621/29, 621/27, 621/75, 236/51, 236/94, 165/11.1
• US Class Current: 62/127
• CPC Class Codes: F25B 2400/075 with parallel compressors
• CPC Class Codes: F25B 2400/22 Refrigeration systems for supermarkets
• CPC Class Codes: F25B 25/005 using primary and secondary systems
• CPC Class Codes: F25B 2500/06 Damage
• CPC Class Codes: F25B 2600/07 Remote controls
• CPC Class Codes: F25B 2600/111 of condenser fans
• CPC Class Codes: F25B 2700/03 Oil level
• 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 2700/21151 at the suction side of the compressor
• CPC Class Codes: F25B 2700/21152 at the discharge side of the compressor
• CPC Class Codes: F25B 2700/21157 at the coil or rotor
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems
• CPC Class Codes: F25B 49/022 Compressor control arrangements
• CPC Class Codes: F25B 5/02 arranged in parallel
• CPC Class Codes: F25B 6/04 arranged in series
• CPC Class Codes: G05D 23/19 characterised by the use of electric means G05D23/1393 takes precedence
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: Y02B 30/70 : Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A commercial refrigeration system has a control system which distributes intelligence to increase granularity of the control and simplify wiring, assembly and installation. Compressors of the refrigeration system each have a bus compatible compressor safety and control module including a processor and sensors. All control and safety modules communicate over a single power and communications line with the controller, providing digital transmissions to the controller of measurements taken by the sensors. The information provided may include that the compressor is outside of a specific safety parameter, so that the controller knows not only that a safety parameter has been traversed, but exactly which one. The control and safety modules are capable of executing commands from the controller to cycle the compressors. The control and safety modules preferably contain sufficient intelligence to continue system operation upon failure of the controller. A compressor is also disclosed which has an intelligent control and safety module. The compressor also houses control and safety devices within a hermetically or semi-hermetically sealed shell.

Claims

1. A commercial refrigeration system for use in a food store comprising:

an evaporator constructed and arranged for cooling food;

a compressor in fluid communication with the evaporator for drawing refrigerant away from the evaporator;

a condenser in fluid communication with the compressor for receiving refrigerant from the compressor, the condenser being constructed and arranged for removing heat from the refrigerant;

an expansion valve in fluid communication with the condenser for receiving refrigerant from the condenser, the expansion valve being constructed and arranged for delivering refrigerant into the evaporator;

a controller for controlling the compressor;

a compressor operating unit associated with the compressor, the operating unit being constructed and arranged for executing commands from the controller to affect the operation of the compressor and for monitoring at least one operating parameter of the compressor and determining whether the operating parameter is within specification;

a low voltage power and communication line extending from the controller to the compressor operating unit and providing electrical power for the operating unit;

wherein the controller and compressor operating unit are constructed and arranged for digital communication over the low voltage power and communication line such that no separate power line for the operating unit must be wired upon installation of the system.

2. The refrigeration system of claim 1 wherein the operating unit comprises a processor and plural sensors in electronic communication with the processor to monitor multiple operating parameters of the compressor.

3. The refrigeration system of claim 2 wherein the operating unit further comprises a switch device in electronic communication with the processor, the switch device being operable to turn the compressor off and on in response to commands from the processor.

4. The refrigeration system of claim 2 wherein the one operating parameter is a safety parameter indicative of whether the compressor is operating in a manner which could damage the compressor.

5. The refrigeration system in a food store as set forth in claim 4 wherein the sensors are constructed and arranged to detect multiple safety parameters for compressor operation, and wherein the processor is configured to activate an alarm when any safety parameter indicates that the compressor is operating in a manner which could damage the compressor.

6. The refrigeration system of claim 1 wherein the one operating parameters is control parameter indicative of the refrigeration load capacity produced by the compressor.

7. The refrigeration system of claim 2 wherein the processor is operable to communicate digital data regarding the operating parameters to the controller.

8. The refrigeration system of claim 3 wherein the processor is configured to operate in a standard operating mode and a controller failure mode, wherein in the standard operating mode the processor receives commands from the controller for operation of the switch device and sends corresponding commands to the switch device.

9. The refrigeration system of claim 8 wherein in the controller failure mode the processor detects that the controller is not functioning and assumes a primary controller function to cycle the compressor through operation of the switch device to maintain normal refrigeration functions.

10. The refrigeration system of claim 1 wherein there are multiple compressors and a compressor operating unit associated with each compressor, each compressor operating unit being powered by and in electronic communication with the controller over the power and communication line.

11. The refrigeration system of claim 10 wherein each of the compressor operating units is constructed and arranged for communicating with the other compressor operating units over the power and communication line.

12. The refrigeration system of claim 11 wherein all compressor operating units are operable in a standard operating mode and in a controller failure mode, wherein in the standard operation mode the compressor is operated in response to commands from the controller.

13. The refrigeration system of claim 12 wherein in the controller failure mode the operating units control the compressors based on the detected operating parameters to maintain a normal refrigeration function independently of the controller.

14. The refrigeration system of claim 11 wherein the operating units are operable to send digital data regarding the operating parameters to the controller, and wherein the controller is configured to determine the operating demands for maintaining a refrigeration level to send to each of the operating units based on the operating parameter information received.

15. The refrigeration system of claim 14 wherein the operating parameters include control parameters indicative of the refrigeration produced by each compressor, and at least one of the sensors of each operating unit being constructed and arranged for detecting one of the control parameters.

16. The refrigeration system of claim 15 wherein the controller is configured to determine whether any of the control parameters received from the operating units should be ignored in determining operating commands.

17. In combination, a food store refrigeration system comprising at least one fixture having evaporator means for cooling the fixture, compressor means having its suction side connected to draw refrigerant vapor from the evaporator means, condenser means connected to the compressor discharge side for receiving high pressure refrigerant from the compressor means and being operative for liquefying the refrigerant, and other means constructed and arranged for delivering refrigerant into the evaporator means, and controller means for controlling, in use, the operation of the compressor means, said controller means comprising:

a compressor control and safety module operatively associated, in use, between the compressor means and the controller means, the compressor control and safety module being constructed and arranged for monitoring at least one operating condition of the compressor means and determining whether it is within a prescribed operating parameter;

a low voltage power and communication line extending from the controller means to the compressor control and safety module and providing electrical power therefor, and wherein the controller means and compressor control and safety module are constructed and arranged for digital communication through said low voltage power and communication line whereby no separate power line for the compressor or compressor control and safety module must be used upon installation of the system.

18. A commercial refrigeration compressor for use in a vapor phase refrigeration system having evaporative cooling means for refrigerating perishable products, the compressor comprising an outer casing, an electric motor, a pressurizing unit constructed and arranged within the casing to be driven, in use, by the motor for drawing vaporous refrigerant from the cooling means at low pressure and pressurizing the vaporous refrigerant to a higher pressure, and an operating unit including a processor, at least one sensor strategically placed within the casing for monitoring an operating parameter of the compressor and being in communication with the processor, switching means connected to the processor for controlling activation and deactivation of the motor, the processor being configured for transmitting data regarding the sensed operating parameter to a master controller remote from the compressor and for receiving compressor control commands from such master controller and for executing such commands.

19. A refrigeration compressor as set forth in claim 18 wherein the processor is configured to detect failure of the master controller and to control said switching means based on operating parameters detected by the sensors and a refrigeration level value stored in the processor to maintain a predetermined refrigeration level.

20. A commercial refrigeration compressor as set forth in claim 19 wherein the processor is configured to communicate operating parameters and control commands with other processors of operating units of other compressors.

21. A commercial refrigeration compressor as set forth in claim 20 wherein the operating parameters include at least one control parameter indicative of the level of refrigeration produced by the compressor and safety parameters indicative of whether the compressor is operating in a manner which could damage the compressor, the operating unit comprising sensors for detecting safety parameters and sensors for detecting control parameters, all sensors of the compressor detecting operating parameters being in electronic communication with the processor.

22. A commercial refrigeration compressor as set forth in claim 21 wherein the control parameter is selected from a group including suction pressure of the compressor and discharge pressure of the compressor, and wherein the safety parameters are selected from a group including oil level, phase loss, phase reversal, motor winding temperature, discharge temperature, discharge pressure and suction pressure.

23. A commercial refrigeration compressor as set forth in claim 22 wherein the compressor further comprises one of a semi-hermetically sealed shell and a hermetically sealed shell, and wherein the motor, pressurizing unit and sensors are disposed within the shell.

24. A commercial refrigeration compressor as set forth in claim 22 wherein the processor is configured to communicate an alarm activation condition to the master controller upon detection of a safety parameter indicating the compressor is operating in a manner which could damage the compressor.

25. A commercial refrigeration compressor as set forth in claim 18 in combination with at least one other compressor of the same construction.

26. The combination as set forth in claim 25 further including the master controller, and a single power and communication line extending between the master controller and the operating units of the compressors, the power and communication line being constructed and arranged for conducting electrical power to the operating units and for conducting communication between the operating units and the master controller.

27. A refrigeration compressor for use in a vapor phase refrigeration system having evaporative cooling means for refrigerating perishable products, the compressor comprising an outer casing, an electric motor, a pressurizing unit constructed and arranged within the casing to be driven, in use, by the motor for drawing vaporous refrigerant from the cooling means at low pressure and pressurizing the vaporous refrigerant to a higher pressure, and an operating unit including a processor, at least one sensor strategically placed within the casing for monitoring an operating parameter of the compressor and being in communication with the processor, switch means connected to the processor for controlling activation and deactivation of the motor, the processor being constructed and arranged to command the switch means in response to a control evaluation of the sensed operating parameter.

28. The refrigeration compressor of claim 27 which includes a master controller receiving sensed data of operating parameters from the processor, and sends control signals to the processor in a normal operational mode.

29. The refrigeration compressor of claim 28 wherein the processor is configured to detect failure of the master controller and to control said switch means based on its independent evaluation of the operating parameters detected by the sensors and a refrigeration level value stored in the processor whereby to maintain a predetermined refrigeration level.

30. The compressor of claim 29 wherein the processor is configured to communicate operating parameters and control commands with other compressor operating units in the same refrigeration system.

31. The refrigeration compressor of claim 30 wherein the operating parameters include at least one control parameter indicative of the level of refrigeration produced by the compressor, and at least one safety parameter indicative of whether the compressor is operating within predetermined safety limits, the operating unit comprising sensors for detecting safety parameters and sensors for detecting control parameters, all sensors of the compressor detecting operating parameters being in electronic communication with the processor.

32. The refrigeration compressor of claim 31 wherein a control parameter is selected from a group including compressor suction pressure and compressor discharge pressure, and wherein a safety parameter is selected from a group including oil failure, phase loss, phase reversal, motor winding temperature, compressor discharge temperature and compressor suction pressure.

33. The refrigeration compressor of claim 32 wherein the compressor further comprises one of a semi-hermetically sealed shell and a hermetically sealed shell, and wherein the motor, pressurizing unit and sensors are disposed within the shell.

34. A commercial refrigeration compressor as set forth in claim 32 wherein the processor is configured to communicate an alarm activation condition to the master controller upon detection of a safety parameter indicating the compressor is operating outside the prescribed safety limits.

35. A commercial refrigeration compressor for use in a commercial refrigeration system of the type used to refrigerate perishable products, the compressor comprising a hermetically sealed shell, an electric motor disposed in the shell, a pressurizing unit connected to the electric motor and disposed in the shell, the pressurizing unit having an inlet and an outlet, the pressurizing unit being constructed and arranged for drawing in generally vaporous refrigerant at low pressure in through the inlet, pressurizing the vaporous refrigerant to a higher pressure and discharging the pressurized refrigerant at said higher pressure out through the outlet, and an operating unit mounted on the pressurizing unit, the operating unit including a processor mounted on the compressor, a sensor disposed within the shell for detecting a control parameter of the compressor indicative of the level of refrigeration produced by the compressor, the sensor being in communication with the processor, a switch device connected to the processor for controlling activation and deactivation of the motor.

36. A commercial refrigeration compressor as set forth in claim 35 wherein operating unit comprises sensors disposed in the shell for detecting safety parameters indicative of whether the compressor is operating in a manner which could damage the compressor, the sensors being in electronic communication with the processor.

37. A commercial refrigeration compressor as set forth in claim 36 wherein the control parameter is selected from a group including suction pressure of the compressor and discharge pressure of the compressor, and wherein the safety parameters are selected from a group including oil failure, phase loss, phase reversal, motor winding temperature, discharge temperature, discharge pressure and suction pressure.

38. A commercial refrigeration compressor as set forth in claim 36 wherein the safety parameters and control parameters collectively define operating parameters of the compressor, all sensors detecting operating parameters of the compressor being hermetically sealed within the shell.

39. A commercial refrigeration compressor as set forth in claim 38 wherein the processor is configured to communicate an alarm activation condition to a controller remote from the compressor upon detection of a safety parameter indicating the compressor is operating in a manner which could damage the compressor.

40. A commercial refrigeration compressor as set forth in claim 38 wherein the processor is configured to communicate information concerning the operating parameters to a controller remote from the compressor.

41. A commercial refrigeration compressor as set forth in claim 40 wherein the processor is configured to detect failure of the controller and to control the switch device based on operating parameters detected by the sensors to maintain a predetermined refrigeration level.

42. A commercial refrigeration compressor as set forth in claim 40 wherein the processor is configured to communicate operating parameters and control commands with other processors of operating units of other compressors.

43. A commercial refrigeration compressor as set forth in claim 35 in combination with at least one other compressor of the same construction.

44. The combination as set forth in claim 43 further including a controller mounted remotely from the compressors, and a single power and communication line extending between the controller and the operating units of the compressors, the power and communication line being constructed and arranged for conducting electrical power to the operating units and for conducting digital communication between the operating units and the controller.

45. In combination a refrigeration system compressor having an operating unit and plural sensors, and a master controller electronically connected to the operating unit, the operating unit comprising:

means for establishing a sensed digital signal representing the value of a refrigerant operating parameter;

means for holding the operating unit in a standard operation mode awaiting command signals from the master controller during a preset time period;

means for transmitting the digital signal to the master controller upon request therefrom and executing any command signal, if received, to change the refrigerating capacity of the compressor as dictated by the command signal;

means for switching the operating unit into a master controller failure mode if no command signal is received within the preset time period;

means for evaluating the sensed signal within the operating unit while in the failure mode and assuming independent control of the compressor to change the refrigeration capacity thereof, and means for setting sequential time periods for the master controller to resume control.

46. A method of distributed intelligence control of a compressor in a refrigeration system having a plurality of fixtures, the compressor having a dedicated operating unit constructed and arranged to monitor at least two sensed operating parameters and being electronically dependent upon a master controller in a standard operation mode, the method comprising the steps of:

receiving sensed signals indicative of refrigerant conditions associated with the compressor into the operating unit;

converting at least one sensed signal to a digital signal representing the value of the refrigeration condition, and holding the operating unit in the standard operation mode for a preselected time period awaiting a command signal from the master controller;

transmitting the digital signal in the operating unit to the master controller in response to a command signal received therefrom within the preselected time period, and executing any command signal from the master controller to change the compressor operation;

assuming an independent control mode in the operating unit when the master controller is in a failure mode and sends no command signal to the operating unit within the preselected time period, and

(a) determining within the operating unit the required compressor operation responsive to the sensed signal and controlling the compressor operation accordingly,

(b) waiting another set period of time for a command signal from the master controller,

(c) repeating steps (a) and (b) if no command signal is received within said other set period of time.

47. The method of claim 46 in which the dedicated operating unit includes the step of (d) functioning in the absence of a controlling intelligence command signal from the master controller during any set period of time.

48. The method of claim 46 in which the dedicated operating unit includes the step of

(e) evaluating the sensed operating parameters to determine if preset safety operating limits for the compressor are traversed while in the standard operation mode, and

(f) taking command of the compressor to avert system damage.

49. The method of claim 46 in which the refrigeration system has multiplexed compressors, each having a dedicated operating unit monitoring operating parameters and including the steps of:

(g) providing a distributed intelligence control of each operating unit with the master controller during the standard operation mode, and

(h) providing independent control in one of said operating units when the master controller is in a failure mode and sends no command signal to the operating unit within the preselected time period, and

(i) receiving in said one operating unit information from the operating unit of each compressor, determining within said one operating unit the required compressor operation responsive to the sensed signal and controlling the operation of all compressors accordingly.

50. A commercial refrigeration compressor system for use in a food store comprising:

a compressor constructed and arranged for fluid communication with an evaporator for drawing refrigerant away from the evaporator, delivering the refrigerant to a condenser and forcing condensed refrigerant through an expansion valve back to the evaporator;

a controller for controlling the compressor;

a compressor operating unit associated with the compressor, the operating unit being constructed and arranged for executing commands from the controller to affect the operation of the compressor and for monitoring at least one operating parameter of the compressor and determining whether the operating parameter is within specification, the compressor operating unit being further constructed and arranged to operate the compressor in opposition to a contrary command from the controller if the operating parameter is not within specification;

a power and communication line extending from the controller to the compressor operating unit and providing electrical power for the operating unit;

wherein the controller and compressor operating unit are constructed and arranged for digital communication over the power and communication line such that no separate power line for the operating unit must be wired upon installation of the system.

51. A refrigeration system as set forth in claim 50 wherein the one operating parameter is a safety parameter indicative of whether the compressor is operating in a manner which could damage the compressor.

52. The refrigeration system in a food store as set forth in claim 51 wherein the compressor operating unit is constructed and arranged to detect multiple operating parameters of the compressor.

53. The refrigeration system of claim 52 wherein the operating parameters include at least one control parameter indicative of the load capacity produced by the compressor.

54. The refrigeration system of claim 53 wherein the compressor operating unit comprises a processor and plural sensors in electronic communication with the processor to monitor multiple operating parameters of the compressor.

55. The refrigeration system as set forth in claim 54 wherein the processor is operable to communicate to the controller digital data including the value of at least one of the operating parameters monitored by the sensors.

56. A method of distributed intelligence control of a controlled unit constituting part of a refrigeration system, the controlled unit having a dedicated operating unit constructed and arranged to monitor an operating parameter and being electronically dependent upon a master controller in a standard operation mode, the method comprising the steps of:

receiving a sensed signal indicative of a condition associated with the controlled unit into the operating unit;

converting the sensed signal to a digital signal representing the value of the condition, and holding the operating unit in the standard operation mode for a preselected time period awaiting a command signal from the master controller;

transmitting the digital signal in the operating unit to the master controller in response to a command signal received therefrom within the preselected time period, and executing any command signal from the master controller to change the controlled unit operation;

assuming an independent control mode in the operating unit when the master controller is in a failure mode and sends no command signal to the operating unit within the preselected time period, and

(a) determining within the operating unit the required controlled unit operation responsive to the sensed signal and controlling the controlled unit operation accordingly,

(b) waiting another set period of time for a command signal from the master controller,

(c) repeating steps (a) and (b) if no command signal is received within said other set period of time.

57. The method of claim 56 in which the refrigeration system has plural controlled units, each having a dedicated operating unit monitoring an operating parameter and including the steps of:

(d) providing a distributed intelligence control of each operating unit with the master controller during the standard operation mode, and

(e) providing independent control in one of said operating units when the master controller is in a failure mode and sends no command signal to the operating unit within the preselected time period, and

(f) receiving in said one operating unit information from the operating unit of each controlled unit, determining within said one operating unit the required controlled unit operation responsive to the sensed signal and controlling the operation of all controlled units accordingly.