BATTERY MONITORING SYSTEM

• US 20160053765A1
• Filed: 08/17/2015
• Published: 02/25/2016
• Est. Priority Date: 08/21/2014
• Status: Active Grant

• Current Assignee: Johnson Controls Tyco IP Holdings LLP (Johnson Controls International plc)
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: KANE, Ajit W., SCHREIBER, Jeb W.
• Granted Patent: US 10,125,780 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F04D 25/0673 Battery powered
• CPC Class Codes: F04D 27/008 Stop safety or alarm devices, e.g. stop-and-go control; Disposition of check-valves
• CPC Class Codes: F04D 27/0292 Stop safety or alarm devices, e.g. stop-and-go control; Disposition of check-valves
• CPC Class Codes: F04D 29/048 magnetic; electromagnetic
• CPC Class Codes: F04D 29/058 magnetic; electromagnetic
• CPC Class Codes: H02J 9/06 with automatic change-over , e.g. UPS systems

Abstract

A method of monitoring a backup battery for a magnetic bearing centrifugal compressor. The method includes: establishing threshold voltage values applicable to the battery backup battery level; monitoring the actual voltage of the battery backup; comparing the actual voltage of the battery backup to the threshold voltage; initiating a soft shutdown of the magnetic bearing centrifugal compressor if the magnetic bearing centrifugal compressor is operating and the actual voltage is below the threshold voltage for a defined period of time; preventing the magnetic bearing centrifugal compressor from starting if the magnetic bearing centrifugal compressor is not operating and the actual voltage is below the threshold voltage; or allowing the magnetic bearing centrifugal compressor to continue operation or begin operation if the actual voltage is greater than the threshold voltage.

Claims

1. A method of monitoring a backup battery for a magnetic bearing centrifugal compressor, the method comprising:

establishing threshold voltage values applicable to the battery backup battery level;

monitoring the actual voltage of the battery backup;

comparing the actual voltage of the battery backup to the threshold voltage;

initiating a soft shutdown of the magnetic bearing centrifugal compressor if the magnetic bearing centrifugal compressor is operating and the actual voltage is below the threshold voltage for a defined period of time;

preventing the magnetic bearing centrifugal compressor from starting if the magnetic bearing centrifugal compressor is not operating and the actual voltage is below the threshold voltage;

allowing the magnetic bearing centrifugal compressor to continue operation or begin operation if the actual voltage is greater than the threshold voltage.

2. The method as recited in claim 1, wherein if the battery voltage is below 12.7 v for 5 seconds and the magnetic bearing centrifugal compressor is not running, a control panel will prevent the magnetic bearing centrifugal compressor from starting until the battery voltage reaches at least 12.8 v.

3. The method as recited in claim 1, further comprising:

displaying a warning indicating low battery voltage if the battery voltage is below the threshold and the magnetic bearing centrifugal compressor is operating;

initiating the soft shutdown of the magnetic bearing centrifugal compressor after the warning has been displayed for the defined period of time.

4. The method as recited in claim 3, wherein the defined period of time is approximately 60 minutes.

5. The method as recited in claim 3, further comprising:

removing the warning if the battery voltage rises above the threshold during the defined period of time;

resetting the defined period of time to its initial setting.

6. The method as recited in claim 1, further comprising:

field adjusting the threshold voltage to compensate for site variables.

7. The method as recited in claim 6, further comprising:

adjusting the threshold voltage based on temperature.

8. The method as recited in claim 1, further comprising:

monitoring voltage at the input to a universal power source of the magnetic bearing centrifugal compressor to determine if the battery backup is connected or disconnected.

9. The method as recited in claim 8, wherein voltage output from the universal power source is different when the battery backup is disconnected in comparison to when the battery backup is connected and is charging, with the battery backup connected the charging voltage is steady over time, when the battery backup is disconnected the voltage varies with a defined or noticeable amplitude.

10. The method as recited in claim 9, wherein in order to properly determine whether the battery backup is connected or disconnected, the amplitude readings over a defined period of time are monitored, whereby if the difference between the minimum and maximum voltage is greater than a defined variance, the sample is recorded and saved.

11. The method as recited in claim 10, wherein If the defined variance is exceeded for 4 consecutive samples a fault is displayed indicating a disconnected battery backup.

12. The method as recited in claim 11, wherein a voltage peak above typical charging voltage range is present if the battery backup is disconnected, if the battery voltage goes above a threshold level, a warning is displayed and is counted as the first sample toward the 4 consecutive samples that lead to the disconnected battery fault.

13. The method as recited in claim 10, wherein the minimum voltage does not change with temperature.

14. The method as recited in claim 1, further comprising:

monitoring the number of times bearings drop a shaft of the magnetic bearing centrifugal compressor while the shaft is rotating during a power loss event;

counting the number of times bearings drop a shaft of the magnetic bearing centrifugal compressor;

comparing the counted the number of times bearings drop a shaft of the magnetic bearing centrifugal compressor to a defined threshold number of times bearings drop a shaft of the magnetic bearing centrifugal compressor;

displaying a fault if the counted number of times bearings drop a shaft of the magnetic bearing centrifugal compressor is greater than the defined threshold the number of times bearings drop a shaft of the magnetic bearing centrifugal compressor;

preventing the magnetic bearing centrifugal compressor from starting until such fault is cleared.

15. A method of monitoring a backup battery for a magnetic bearing centrifugal compressor, the method comprising:

monitoring voltage amplitude over a period of time at the input to a universal power source of the magnetic bearing centrifugal compressor to determine if the battery backup is connected or disconnected, whereby if the difference between the minimum and maximum voltage is greater than a defined variance, the sample is recorded and saved;

displaying a fault if the defined variance is exceeded for a defined amount of consecutive samples indicating a disconnected battery backup;

initiating a soft shutdown of the magnetic bearing centrifugal compressor if the magnetic bearing centrifugal compressor is operating and the defined variance is exceeded for a defined amount of consecutive samples indicating a disconnected battery backup;

preventing the magnetic bearing centrifugal compressor from starting if the magnetic bearing centrifugal compressor is not operating and the defined variance is exceeded for a defined amount of consecutive samples indicating a disconnected battery backup;

allowing the magnetic bearing centrifugal compressor to continue operation or begin operation if the defined variance is not exceeded for a defined amount of consecutive samples indicating a disconnected battery backup.

16. The method as recited in claim 15, wherein voltage output from the universal power source is different when the battery backup is disconnected in comparison to when the battery backup is connected and is charging, with the battery backup connected the charging voltage is steady over time, when the battery backup is disconnected the voltage varies with a defined or noticeable amplitude.

17. The method as recited in claim 16, wherein if the difference between the minimum and maximum voltage is greater than the defined variance, the sample is recorded and saved.

18. The method as recited in claim 17, wherein if the defined variance is exceeded for 4 consecutive samples a fault is displayed indicating a disconnected battery backup.

19. The method as recited in claim 18, wherein a voltage peak above typical charging voltage range is present if the battery backup is disconnected, if the battery voltage goes above a threshold level, a warning is displayed and is counted as the first sample toward the 4 consecutive samples that lead to the disconnected battery fault.

20. A method of monitoring a backup battery for a magnetic bearing centrifugal compressor, the method comprising:

monitoring the number of times bearings drop a shaft of the magnetic bearing centrifugal compressor while the shaft is rotating during a power loss event;

counting the number of times bearings drop a shaft of the magnetic bearing centrifugal compressor;

comparing the counted the number of times bearings drop a shaft of the magnetic bearing centrifugal compressor to a defined threshold number of times bearings drop a shaft of the magnetic bearing centrifugal compressor;

displaying a fault if the counted number of times bearings drop a shaft of the magnetic bearing centrifugal compressor is greater than the defined threshold the number of times bearings drop a shaft of the magnetic bearing centrifugal compressor;

preventing the magnetic bearing centrifugal compressor from starting until such fault is cleared.