Compressor having a control and diagnostic module

• US 9,310,439 B2
• Filed: 09/23/2013
• Issued: 04/12/2016
• Est. Priority Date: 09/25/2012
• Status: Active Grant

• Current Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Original Assignee: Emerson Climate Technologies Incorporated (Emerson Electric Company)
• Inventors: Pham, Hung M., Alsaleem, Fadi M.
• Primary Examiner(s): Chan, Kawing
• Application Number:
  US14/033,604
• Publication Number:
  US 20140084836A1
• Time in Patent Office: 932 Days
• Field of Search: 318/490
• US Class Current: 1/1
• CPC Class Codes: F04B 2203/0201 Current
• CPC Class Codes: F04B 2203/0202 Voltage
• CPC Class Codes: F04B 35/04 the means being electric
• CPC Class Codes: F04B 49/06 Control using electricity regulating by means of floats actuating electric switches F04B49/04
• CPC Class Codes: F04B 49/10 Other safety measures
• CPC Class Codes: F04C 18/02 of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
• CPC Class Codes: F04C 18/0215 where only one member is moving
• CPC Class Codes: F04C 2240/808 Electronic circuits (e.g. inverters) installed inside the machine
• CPC Class Codes: F04C 2240/81 Sensor, e.g. electronic sensor for control or monitoring
• CPC Class Codes: F04C 2270/03 Torque
• CPC Class Codes: F04C 2270/07 Electric current
• CPC Class Codes: F04C 2270/19 Temperature
• CPC Class Codes: F04C 2270/22 Temperature difference
• CPC Class Codes: F04C 2270/60 Prime mover parameters
• CPC Class Codes: F04C 2270/80 Diagnostics
• CPC Class Codes: F04C 2270/86 Detection
• CPC Class Codes: F04C 2270/90 Remote control, e.g. wireless, via LAN, by radio, or by a wired connection from a central computer
• CPC Class Codes: F04C 28/28 Safety arrangements; Monitoring
• CPC Class Codes: F04C 29/0085 Prime movers
• CPC Class Codes: F25B 49/022 Compressor control arrangements
• CPC Class Codes: G01R 31/343 : in operation
• CPC Class Codes: G01R 31/64 : Testing of capacitors
• CPC Class Codes: H02P 25/04 : Single phase motors, e.g. capacitor motors

Abstract

An apparatus includes a voltage sensor, a current sensor, and a controller. The voltage sensor measures voltage values of alternating current power supplied to a capacitor. The capacitor is electrically coupled to a compressor. The current sensor measures current values of the alternating current power. The controller is configured to receive the voltage values and the current values. The controller is configured to determine a first power factor value based on at least one of the voltage values and at least one of the current values. The controller is configured to selectively detect a first capacitor fault in response to concurrent determination that (i) the first power factor value is less than a first power factor threshold and (ii) a first current value of the current values is greater than a first current threshold. The first capacitor fault indicates that a capacitance of the capacitor has degraded.

Claims

1. An apparatus comprising:

a voltage sensor that measures a plurality of voltage values of alternating current power supplied to a capacitor, wherein the capacitor is electrically coupled to a compressor;

a current sensor that measures a plurality of current values of the alternating current power; and

a controller configured to;

receive the plurality of voltage values;

receive the plurality of current values;

determine a first power factor value based on at least one of the plurality of voltage values and at least one of the plurality of current values; and

selectively detect a first capacitor fault in response to concurrent determination that (i) the first power factor value is less than a first power factor threshold and (ii) a first current value of the plurality of current values is greater than a first current threshold, wherein the first capacitor fault indicates that a capacitance of the capacitor has degraded.

2. A system comprising;

the apparatus of claim 1;

the compressor; and

the capacitor.

3. The apparatus of claim 1 wherein the controller is configured to disable the compressor in response to detection of the first capacitor fault.

4. The apparatus of claim 1 wherein the controller is configured to detect the first capacitor fault in response to concurrent determination that (i) a measured temperature value is stable, (ii) the first power factor value is less than the first power factor threshold, and (iii) the first current value is greater than the first current threshold.

5. The apparatus of claim 4 wherein the measured temperature value comprises a difference between a supply air temperature and a return air temperature, wherein the supply air temperature and the return air temperature are measured on opposite sides of an evaporator associated with the compressor.

6. The apparatus of claim 4 wherein the measured temperature value comprises one of (i) a refrigerant temperature at a discharge side of the compressor or (ii) a refrigerant temperature at a condensing coil associated with the compressor.

7. The apparatus of claim 4 wherein the controller is configured to determine the first power factor threshold by subtracting a predetermined offset from a previous power factor value.

8. The apparatus of claim 7 wherein the controller is configured to determine the first power factor threshold as 10% less than a power factor value determined 15 seconds earlier.

9. The apparatus of claim 4 wherein the controller is configured to determine the first current threshold by adding a predetermined offset to a previous one of the plurality of current values.

10. The apparatus of claim 1 wherein the controller is configured to detect a second capacitor fault in response to the power factor value being below a predetermined threshold subsequent to installation of the capacitor, wherein the second capacitor fault indicates that the capacitor is an incorrect type.

11. The apparatus of claim 1 wherein the controller is configured to detect a second capacitor fault in response to concurrent determination that (i) zero current is flowing through the capacitor and (ii) a measured temperature value is below a predetermined threshold, wherein the second capacitor fault indicates that the capacitor is an open circuit.

12. The apparatus of claim 11 wherein the measured temperature value comprises one of (i) a difference between a supply air temperature and a return air temperature, (ii) a refrigerant temperature at a discharge side of the compressor, or (iii) a refrigerant temperature at a condensing coil associated with the compressor, wherein the supply air temperature and the return air temperature are measured on opposite sides of an evaporator associated with the compressor.

13. A method comprising:

measuring a plurality of voltage values of alternating current power supplied to a capacitor, wherein the capacitor is electrically coupled to a compressor;

measuring a plurality of current values of the alternating current power;

determining a first power factor value based on at least one of the plurality of voltage values and at least one of the plurality of current values; and

selectively detecting a first capacitor fault in response to concurrent determination that (i) the first power factor value is less than a first power factor threshold and (ii) a first current value of the plurality of current values is greater than a first current threshold, wherein the first capacitor fault indicates that a capacitance of the capacitor has degraded.

14. The method of claim 13 further comprising disabling the compressor in response to detection of the first capacitor fault.

15. The method of claim 13 further comprising detecting the first capacitor fault in response to concurrent determination that (i) a measured temperature value is stable, (ii) the first power factor value is less than the first power factor threshold, and (iii) the first current value is greater than the first current threshold.

16. The method of claim 15 wherein the measured temperature value comprises a difference between a supply air temperature and a return air temperature, wherein the supply air temperature and the return air temperature are measured on opposite sides of an evaporator associated with the compressor.

17. The method of claim 15 wherein the measured temperature value comprises one of (i) a refrigerant temperature at a discharge side of the compressor or (ii) a refrigerant temperature at a condensing coil associated with the compressor.

18. The method of claim 15 further comprising determining the first power factor threshold by subtracting a predetermined offset from a previous power factor value.

19. The method of claim 18 further comprising determining the first power factor threshold as 10% less than a power factor value determined 15 seconds earlier.

20. The method of claim 15 further comprising determining the first current threshold by adding a predetermined offset to a previous one of the plurality of current values.

21. The method of claim 13 further comprising detecting a second capacitor fault in response to the power factor value being below a predetermined threshold subsequent to installation of the capacitor, wherein the second capacitor fault indicates that the capacitor is an incorrect type.

22. The method of claim 13 further comprising detecting a second capacitor fault in response to concurrent determination that (i) zero current is flowing through the capacitor and (ii) a measured temperature value is below a predetermined threshold, wherein the second capacitor fault indicates that the capacitor is an open circuit.

23. The method of claim 22 wherein the measured temperature value comprises one of (i) a difference between a supply air temperature and a return air temperature, (ii) a refrigerant temperature at a discharge side of the compressor, or (iii) a refrigerant temperature at a condensing coil associated with the compressor, wherein the supply air temperature and the return air temperature are measured on opposite sides of an evaporator associated with the compressor.

24. A non-transitory computer-readable medium storing instructions executable on a processor, the instructions comprising:

measuring a plurality of voltage values of alternating current power supplied to a capacitor, wherein the capacitor is electrically coupled to a compressor;

measuring a plurality of current values of the alternating current power;

determining a first power factor value based on at least one of the plurality of voltage values and at least one of the plurality of current values; and

selectively detecting a first capacitor fault in response to concurrent determination that (i) the first power factor value is less than a first power factor threshold and (ii) a first current value of the plurality of current values is greater than a first current threshold, wherein the first capacitor fault indicates that a capacitance of the capacitor has degraded.