Adaptive control for a refrigeration system using pulse width modulated duty cycle scroll compressor

• US 6,449,972 B2
• Filed: 01/16/2001
• Issued: 09/17/2002
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: Emerson Climate Technologies Incorporated (Emerson Electric Company)
• Original Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Inventors: Pham, Hung M., Caillat, Jean-Luc M., Singh, Abtar, Bass, Mark
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US09/760,994
• Publication Number:
  US 20010002239A1
• Time in Patent Office: 609 Days
• Field of Search: 622/283, 622/29, 622/281, 622/285, 622/284, 625/10, 621/961, 621/962, 621/963, 236/78.D, 236/1.EA
• US Class Current: 62/228.3
• CPC Class Codes: A47F 3/04 air-conditioned, refrigerated refrigerators F25D; heating arrangements specially adapted for transparent or reflecting areas H05B3/84
• CPC Class Codes: F04C 18/0215 where only one member is moving
• CPC Class Codes: F04C 2270/015 Controlled or regulated
• CPC Class Codes: F04C 2270/86 Detection
• CPC Class Codes: F04C 23/008 Hermetic pumps
• CPC Class Codes: F04C 27/005 Axial sealings for working fluid
• 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: F04C 28/02 specially adapted for several pumps connected in series or in parallel
• CPC Class Codes: F04C 28/06 specially adapted for stopping, starting, idling or no-load operation
• CPC Class Codes: F04C 28/08 characterised by varying the rotational speed
• CPC Class Codes: F04C 28/22 by changing the eccentricity between cooperating members
• CPC Class Codes: F04C 28/265 being obtained by displacing a lateral sealing face
• CPC Class Codes: F04C 28/28 Safety arrangements; Monitoring
• CPC Class Codes: F25B 1/04 with compressor of rotary type F25B1/005, F25B1/10 take precedence
• CPC Class Codes: F25B 2400/22 Refrigeration systems for supermarkets
• CPC Class Codes: F25B 2600/0261 external to the compressor
• CPC Class Codes: F25B 2700/193 of the compressor
• CPC Class Codes: F25B 2700/1933 Suction pressures
• CPC Class Codes: F25B 2700/2106 of fresh outdoor air
• CPC Class Codes: F25B 2700/2117 of an evaporator
• CPC Class Codes: F25B 2700/21174 : of the refrigerant at the inlet of the evaporator
• CPC Class Codes: F25B 2700/21175 : of the refrigerant at the outlet of the evaporator
• CPC Class Codes: F25B 41/22 : between evaporator and compressor
• CPC Class Codes: F25B 41/35 : by rotary motors, e.g. by stepping motors
• CPC Class Codes: F25B 49/005 : of safety devices F25B49/02 and F25B49/04 take precedence
• CPC Class Codes: F25B 49/022 : Compressor control arrangements
• CPC Class Codes: F25B 5/02 : arranged in parallel
• CPC Class Codes: G05D 23/1909 : whose output amplitude can only take two discrete values
• CPC Class Codes: Y02B 30/70 : Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A control for a refrigeration system serviced by a special pulse width modulated compressor coupled to a condenser and evaporator. The system can be of the distributed type wherein the condenser and compressor may be coupled to service a group of adjacent refrigeration cases, wherein each case would have its own evaporator. A controller is coupled to a load sensor for producing a variable duty cycle control signal in which the duty cycle is a function of demand for cooling. Moreover, fuzzy logic techniques may be utilized in order to provide self adaptive tuning control for the system.

Claims

1. A compressor control system comprising:

a scroll compressor for compressing a gas from a suction pressure to a discharge pressure, said compressor including intermeshing scroll wraps defining moving fluid pockets, said scroll wraps being movable relative to one another to develop pressure and compress said gas;

a pressure sensor for sensing said suction pressure;

a control mechanism operably engaging said intermeshing scroll wraps to develop pressure while maintaining substantially constant relative movement of said scroll wraps; and

a controller operating said control mechanism and responsive to said pressure sensor for providing a variable duty cycle control signal for modulating an operating capacity of said scroll compressor based upon said suction pressure.

2. The control system of claim 1, wherein said control mechanism comprises a solenoid valve, said solenoid valve being energized in a pulse width modulated manner to manipulate said intermeshing scroll wraps to alter said fluid pressure developed.

3. The control system of claim 1, wherein said intermeshing scroll wraps define a fluid chamber, said fluid chamber being selective communication with one of said suction pressure and said discharge pressure to modulate said operating capacity of said scroll compressor.

4. The control system of claim 3, wherein said control mechanism comprises a solenoid valve for controlling fluid flow to said fluid chamber.

5. A control system comprising:

a first housing;

a first evaporator disposed in said housing;

a condenser coupled in fluid communication with said first evaporator;

a compressor coupled in fluid communication with said first evaporator and said condenser, said compressor being operable to compress a gas from a suction pressure to a discharge pressure, said compressor comprising a pulse width modulated variable capacity scroll compressor having intermeshing scroll wraps defining moving pockets, said scroll wraps being movable relative to one another to develop pressure and compress said gas;

a pressure sensor for sensing said suction pressure; and

a control mechanism operably engaging said intermeshing scroll wraps to develop said pressure, while maintaining substantially constant relative movement of said scroll wraps; and

a controller operating said control mechanism and responsive to said pressure sensor for providing a variable duty cycle control signal for modulating an operating capacity of said scroll compressor based upon said suction pressure.

6. The control system of claim 5, wherein said control mechanism comprises a solenoid valve, said solenoid valve being energized in a pulse width modulated manner to manipulate said intermeshing scroll wraps to alter said fluid pressure developed.

7. The control system of claim 5, wherein said intermeshing scroll wraps define a fluid chamber, said fluid chamber being in selective communication with one of said suction pressure and said discharge pressure to modulate said operating capacity of said scroll compressor.

8. The control system of claim 7, wherein said control mechanism comprises a solenoid valve for controlling fluid flow to said fluid chamber.

9. The control system of claim 5, further comprising a second housing having a second evaporator disposed therein, said second evaporator being coupled in fluid communication with said condenser.

10. The control system of claim 5, further comprising a second housing having a second evaporator disposed therein, said second evaporator being coupled in fluid communication with said compressor.