SYSTEM AND METHOD FOR CALIBRATING PARAMETERS FOR A REFRIGERATION SYSTEM WITH A VARIABLE SPEED COMPRESSOR

• US 20090094997A1
• Filed: 10/07/2008
• Published: 04/16/2009
• Est. Priority Date: 10/08/2007
• Status: Active Grant

• Current Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Original Assignee: Emerson Climate Technologies Incorporated (Emerson Electric Company)
• Inventors: McSweeney, Daniel L.
• Granted Patent: US 9,541,907 B2
• Time in Patent Office: Days
• US Class Current: 62/126
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2600/021 Inverters therefor
• CPC Class Codes: F25B 2700/151 of the compressor motor
• 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 2700/2117 of an evaporator
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence
• CPC Class Codes: F25B 49/025 Motor control arrangements
• CPC Class Codes: G05B 13/024 in which a parameter or coefficient is automatically adjusted to optimise the performance
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A system and method for calibrating parameters for a refrigeration system having a variable speed compressor is provided. A compressor is connected to a condenser and an evaporator. A condenser sensor outputs a condenser signal corresponding to at least one of a sensed condenser pressure and a sensed condenser temperature. An inverter drive modulates a frequency of electric power delivered to the compressor to modulate a speed of the compressor. A control module is connected to the inverter drive and determines a measured condenser temperature based on the condenser signal, monitors electric power data and compressor speed data from the inverter drive, calculates a derived condenser temperature based on the electric power data, the compressor speed data, and compressor map data for the compressor, compares the measured condenser temperature with the derived condenser temperature, and updates the compressor map data based on the comparison.

Claims

1. A system comprising:

a compressor connected to a condenser and an evaporator;

a condenser sensor that outputs a condenser signal corresponding to at least one of a sensed condenser pressure and a sensed condenser temperature;

an inverter drive that modulates a frequency of electric power delivered to said compressor to modulate a speed of said compressor;

a control module connected to said inverter drive that determines a measured condenser temperature based on said condenser signal, that monitors electric power data and compressor speed data from said inverter drive, that calculates a derived condenser temperature based on said electric power data, said compressor speed data, and compressor map data for said compressor, and that compares said measured condenser temperature with said derived condenser temperature, and selectively updates said compressor map data based on said comparison.

2. The system of claim 1 wherein said control module calculates a difference between said derived condenser temperature and said calculated condenser temperature, compares said difference with a predetermined threshold, and selects one of said derived condenser temperature and said calculated condenser temperature as being more accurate when said difference is greater than said predetermined threshold.

3. The system of claim 2 wherein said control module generates an alarm when said difference is greater than said predetermined threshold.

4. A method comprising:

receiving a condenser signal corresponding to at least one of a condenser pressure and a condenser temperature of a condenser connected to a compressor and an evaporator;

modulating a speed of said compressor with an inverter drive configured to modulate a frequency of electric power delivered to said compressor;

receiving electric power data and compressor speed data from said inverter drive;

calculating a derived condenser temperature based on said electric power data, said compressor speed data, and compressor map data associated with said compressor;

determining a measured condenser temperature based on said condenser signal;

comparing said derived condenser temperature with said measured condenser temperature; and

selectively updating said compressor map data based on said comparing.

5. The method of claim 4 further comprising calculating a difference between said derived condenser temperature and said calculated condenser temperature, comparing said difference with a predetermined threshold, and selecting one of said derived condenser temperature and said calculated condenser temperature as being more accurate when said difference is greater than said predetermined threshold.

6. The method of claim 4 further comprising generating an alarm when said difference is greater than said predetermined threshold.

7. A system comprising:

a compressor connected to a condenser and an evaporator;

an evaporator sensor that outputs an evaporator signal corresponding to at least one of a sensed evaporator pressure and a sensed evaporator temperature;

a discharge temperature sensor that outputs a discharge temperature signal corresponding to a temperature of refrigerant exiting said compressor;

an inverter drive that modulates a frequency of electric power delivered to said compressor to modulate a speed of said compressor;

a control module connected to said inverter drive that determines a measured evaporator temperature based on said evaporator signal, that monitors electric power data and compressor speed data from said inverter drive, that calculates a derived evaporator temperature based on said electric power data, said compressor speed data, said discharge temperature signal, and compressor map data for said compressor, that compares said measured condenser temperature with said derived condenser temperature, and that selectivley updates said compressor map data based on said comparison.

8. The system of claim 7 wherein said control module calculates a difference between said derived evaporator temperature and said calculated evaporator temperature, compares said difference with a predetermined threshold, and selects one of said derived evaporator temperature and said calculated evaporator temperature as being more accurate when said difference is greater than said predetermined threshold.

9. The system of claim 8 wherein said control module generates an alarm when said difference is greater than said predetermined threshold.