SYSTEM AND METHOD FOR DETECTING A FAULT CONDITION IN A COMPRESSOR

• US 20090324428A1
• Filed: 06/29/2009
• Published: 12/31/2009
• Est. Priority Date: 06/29/2008
• Status: Active Grant

• Current Assignee: Kulthorn Kirby Public Company Limited
• Original Assignee: Bristol Compressors International Incorporated (Kulthorn Kirby Public Company Limited)
• Inventors: TONER, Justin M., HIX, Scott, GILLIAM, David R., WILLIAMS, John R., TRENT, Mark R., DENZAU, Richard C., EDWARDS, Jerry D., TOLBERT, John W. JR., WAMPLER, Tim M., MOODY, Bruce A., CHUMLEY, Eugene K.
• Granted Patent: US 8,904,814 B2
• Time in Patent Office: Days
• US Class Current: 417/44.1
• CPC Class Codes: F04B 2203/0201 Current
• CPC Class Codes: F04B 2203/0209 Rotational speed
• CPC Class Codes: F04B 39/0207 with lubrication control systems

Abstract

A system and method for determining a fault condition in a compressor is provided. The current of a motor drive powering the compressor and the outdoor ambient temperature are measured and used to determine if a fault condition or a potential fault condition is present in the compressor. If a fault condition is determined to be present, the compressor can be shutdown to avoid damage to the compressor. If a potential fault condition is determined, remedial action can be taken to attempt to prevent the fault condition from occurring and shutting down the compressor.

Claims

1. A method of determining fault conditions in a compressor for a heating, ventilation, and air conditioning (HVAC) system comprising:

measuring an outdoor ambient temperature for the HVAC system;

measuring a current of a motor drive for the compressor;

selecting a predetermined range of current values for a motor drive current based on the measured outdoor ambient temperature, the predetermined range of current values being bounded by an upper current value and a lower current value, and the predetermined range of current values corresponding to acceptable operation of the compressor;

comparing the measured current to the predetermined range of current values;

determining a potential fault condition in response to the measured current being greater than the upper current value or less than the lower current value; and

changing an operating condition of the compressor in response to the determined potential fault condition.

2. The method of claim 1 further comprising:

determining a maximum current value for the motor drive current based on the measured outdoor ambient temperature;

comparing the measured current to the maximum current value; and

shutting down the compressor in response to the measured current being greater than the maximum current value.

3. The method of claim 1 further comprising:

determining a minimum current value for the motor drive current based on the measured outdoor ambient temperature;

comparing the measured current to the minimum current value; and

shutting down the compressor in response to the measured current being less than the minimum current value.

4. The method of claim 1 wherein the changing an operating condition of the compressor comprises at least one of increasing compressor speed, decreasing compressor speed, adjusting a voltage provided to a motor of the compressor, opening a valve, closing a valve or adjusting a fan speed of a component of the HVAC system.

5. The method of claim 1 wherein the determining a potential fault condition comprises determining a high pressure condition in response to the measured current being greater than the upper current limit of the predetermined range of current values.

6. The method of claim 1 wherein the determining a potential fault condition comprises determining a high current condition in response to the measured current being greater than the upper current limit of the predetermined range of current values.

7. The method of claim 1 wherein the determining a potential fault condition comprises determining a low pressure condition in response to the measured current being less than the lower current limit of the predetermined range of current values.

8. The method of claim 1 wherein the determining a potential fault condition further comprises determining a potential fault condition in response to the measured current being greater than the upper current value or less than the lower current value and at least one additional measured operating parameter.

9. The method of claim 8 wherein the at least one additional operating parameter comprises the measured outdoor ambient temperature.

10. A system comprising:

a compressor;

a motor drive configured to receive power from an AC power source and to provide power to the compressor, the motor drive comprising a first sensor to measure a value representative of a current in the motor drive;

a second sensor positioned to measure a value representative of the outdoor ambient temperature; and

a controller to control operation of the motor drive, the controller comprising;

an interface to receive the value representative of a current in the motor drive and the value representative of the outdoor ambient temperature; and

a processor to process the value representative of a current in the motor drive and the value representative of the outdoor ambient temperature to determine for a fault condition in the compressor and to initiate a remedial action upon a fault condition being determined.

11. The system of claim 10 wherein the controller comprises a memory device storing predetermined ranges of current values for the motor drive current based on the measured outdoor ambient temperature, each predetermined range of current values being bounded by an upper current value and a lower current value, and each predetermined range of current values corresponding to acceptable operation of the compressor at the corresponding outdoor ambient temperature.

12. The system of claim 11 wherein the processor is configured to compare the value representative of a current in the motor drive to the predetermined range of current values corresponding to the value representative of the outdoor ambient temperature.

13. The system of claim 12 wherein the processor is configured to determine a fault condition in response to the value representative of a current in the motor drive being greater than the upper current value or less than the lower current value of the predetermined range of current values corresponding to the value representative of the outdoor ambient temperature.

14. The system of claim 11 wherein:

the memory device stores a maximum current value for the motor drive current based on the value representative of the outdoor ambient temperature; and

the processor is configured to shut down the compressor in response to the value representative of a current in the motor drive being greater than the maximum current value.

15. The system of claim 11 further comprising:

the memory device stores a minimum current value for the motor drive current based on the value representative of the outdoor ambient temperature; and

the processor is configured to shut down the compressor in response to the value representative of a current in the motor drive being less than the minimum current value.

16. The system of claim 10 wherein the processor is configured to initiate at least one of increasing compressor speed, decreasing compressor speed, adjusting a voltage provided to a motor of the compressor, opening a valve, closing a valve or adjusting a fan speed of a component of the HVAC system in response to a fault condition being determined.

17. The system of claim 10 wherein the processor is configured to initiate a remedial action by permitting continued operation of the compressor and the motor drive without change for a predetermined time period.