Power management system having automatic calibration

• US 9,577,558 B2
• Filed: 07/03/2014
• Issued: 02/21/2017
• Est. Priority Date: 07/03/2014
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Kresca, Michael James, Nee, Brett Michael, Urbanc, Matthew J.
• Primary Examiner(s): NGUYEN, VIET P
• Application Number:
  US14/323,691
• Publication Number:
  US 20160006383A1
• Time in Patent Office: 964 Days
• Field of Search: 322/15
• US Class Current: 1/1
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/14 for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
• CPC Class Codes: H02P 9/48 Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle H02P9/04 - H02P9/46 take precedence

Abstract

A power management system having automatic calibration is disclosed. The power management system may have an alternator and an electronic control unit. The electronic control unit may be configured to determine a reference voltage based on at least one measured operating condition of the alternator. The reference voltage may correspond to an overloading threshold of the alternator. The electronic control unit may be further configured to monitor a voltage of the alternator and, when the monitored voltage is less than the reference voltage, perform a corrective action to increase a power output of the alternator.

Claims

1. A power management system, comprising:

an alternator; and

an electronic control unit configured to;

measure an operating voltage of the alternator across at least one load when the alternator is operating at a capability condition,

the capability condition indicating that the alternator is operating with a particular speed when the alternator is not overloaded;

determine a threshold voltage of the alternator based on the operating voltage when the alternator is operating at the capability condition,

when determining the threshold voltage, the electronic control unit is configured to determine the threshold voltage based on the operating voltage and a tolerance factor associated with the alternator operating at the capability condition,

the threshold voltage being determined each time the alternator returns to operating at the capability condition after not operating at the capability condition;

monitor a voltage of the alternator; and

when the monitored voltage is less than the threshold voltage, perform a corrective action to increase a power output of the alternator.

2. The power management system of claim 1, wherein the particular speed is within a predetermined range.

3. The power management system of claim 2, wherein the predetermined range is approximately two to five times an alternator idling speed.

4. The power management system of claim 1, wherein the particular speed is equal to or greater than a predetermined threshold.

5. The power management system of claim 4, wherein the predetermined threshold is approximately two times an alternator idling speed.

6. The power management system of claim 1, wherein the capability condition includes an electrical load on the alternator that is less than a predetermined threshold.

7. The power management system of claim 1, wherein, when determining the operating voltage, the electronic control unit is configured to determine an average of voltages measured across the at least one load while the alternator operates according to the capability condition for a predetermined period of time.

8. The power management system of claim 1, wherein the tolerance factor is based on a range of normal output voltage variation of the alternator when the alternator is to operating at the capability condition.

9. The power management system of claim 1, wherein, when performing the corrective action, the electronic control unit is configured to increase a speed of the alternator.

10. The power management system of claim 9, wherein:

the alternator is operably coupled to an engine, and

when performing the corrective action, the electronic control unit is configured to increase a speed of the engine to increase the speed of the alternator.

11. A method of managing a power output of an alternator, the method comprising:

measuring an operating voltage of the alternator across at least one load when the alternator is operating at a capability condition,

the capability condition indicating that the alternator is operating at a particular speed when the alternator is not overloaded;

determining a threshold voltage based on the operating voltage and a tolerance factor, when the alternator is operating at the capability condition,

the tolerance factor being associated with the alternator operating at the capability condition,

the threshold voltage being determined each time the alternator returns to operating at the capability condition after not operating at the capability condition;

monitoring a voltage of the alternator; and

when the monitored voltage is less than the threshold voltage, increasing a speed of the alternator to increase the power output of the alternator.

12. The method of claim 11, wherein the particular speed is within a predetermined range that is based on an alternator idling speed.

13. The method of claim 11, wherein the particular speed is equal to or greater than a predetermined threshold that is based on an alternator idling speed.

14. The method of claim 11, wherein the capability condition includes an electrical load on the alternator that is less than a predetermined threshold.

15. The method of claim 11, wherein determining the operating voltage includes determining an average of voltages measured across the at least one load while the alternator operates according to the capability condition for a predetermined period of time.

16. The method of claim 11, wherein the tolerance factor includes a range of normal output voltage variation of the alternator when the alternators is operating at the capability condition.

17. A machine, comprising:

an engine;

an alternator operably coupled to the engine; and

an electronic control unit configured to;

measure an operating voltage of the alternator across at least one load when the alternator is operating at a capability condition,

the capability condition indicating that the alternator is operating with a particular speed when the operator is not overloaded;

determine a threshold voltage based on the operating voltage and a tolerance factor associated with the alternator operating at the capability condition, when the alternator is operating at the capability condition,

the threshold voltage being determined each time the alternator returns to operating at the capability condition after not operating at the capability condition;

monitor a voltage of the alternator; and

when the monitored voltage of the alternator is less than the threshold voltage, increase a speed of the engine to increase a power output of the alternator.