Multiple current sensor system

Patent metadata

Field	Value
Publication number	US-10109994-B2
Application number	US-201615079531-A
Country	US
Kind code	B2
Filing date	Mar 24, 2016
Priority date	Mar 24, 2016
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

Provided herein are improved current monitoring systems for monitoring currents having large ranges. A current monitor can include two or more current sensors. At least two of the current sensors can have different current measurement ranges and different current measurement sensitivities. Each current sensor can be associated with one or more current monitoring thresholds. A time delay or time threshold can correspond to each current monitoring threshold. Each current sensor can monitor a same current having a large range of possible current values. When a predetermined current threshold is exceeded for an amount of time exceeding a corresponding time threshold, a signal can be generated by the current sensor. The generated signal can indicate that the measured current exceeds the predetermined current threshold for the corresponding predetermined period of time.

First claim

The invention claimed is:

1. An apparatus, comprising:
a power source;
a relay coupled to the power source;
a load coupled to the relay, wherein the relay couples the load to the power source when the relay is in a closed position;
a current monitor coupled to the relay; and
a controller coupled to the current monitor, wherein the current monitor includes a first current sensor and a second current sensor, wherein the first and second current sensors each measure a current of the relay, wherein the first current sensor determines when the current of the relay exceeds a first current set point within a first current measurement range for a first period of time and the second current sensor determines when the current of the relay exceeds a second current set point within a second current measurement range for a second period of time.

2. The apparatus of claim 1 , the first current sensor having a first current measurement sensitivity and the second current sensor having a second current measurement sensitivity.

3. The apparatus of claim 2 , wherein the first current measurement range is larger than the second current measurement range.

4. The apparatus of claim 3 , wherein the first current measurement sensitivity is larger than the second current measurement sensitivity.

5. The apparatus of claim 4 , wherein the first period of time is less than the second period of time.

6. The apparatus of claim 1 , wherein the power source is a battery.

7. The apparatus of claim 1 , wherein the controller is an engine control unit (ECU).

8. The apparatus of claim 1 , wherein the first current sensor generates a first signal when the current of the relay exceeds the first current set point for the first period of time.

9. The apparatus of claim 8 , wherein the first signal is provided to the controller.

10. The apparatus of claim 9 , wherein the controller causes the relay to open to decouple the load from the power source based on receipt of the first signal.

11. The apparatus of claim 8 , wherein the first signal causes the relay to open to decouple the load from the power source.

12. The apparatus of claim 8 , wherein the first signal includes an alarm signal indicating that the current of the relay exceeds the first current set point for the first period of time.

13. The apparatus of claim 8 , wherein the second current sensor generates a second signal when the current of the relay exceeds the second current set point for the second period of time.

14. The apparatus of claim 13 , wherein the second signal is provided to the controller.

15. The apparatus of claim 14 , wherein the controller causes the relay to open to decouple the load from the power source based on receipt of the second signal.

16. The apparatus of claim 13 , wherein the second signal causes the relay to open to decouple the load from the power source.

17. The apparatus of claim 13 , wherein the second signal includes an alarm signal indicating that the current of the relay exceeds the second current set point for the second period of time.

18. A method, comprising:
determining a first current threshold for a first current sensor, the first current sensor having a first current measurement range and a first current measurement sensitivity;
determining a second current threshold for a second current sensor, the second current sensor having a second current measurement range and a second current measurement sensitivity, wherein the first current threshold, the first current measurement range, and the first current measurement sensitivity are larger than the second current threshold, the second current measurement range, and the second current measurement sensitivity;
determining a first time period corresponding to the first current threshold for the first current sensor;
determining a second time period corresponding to the second current threshold for the second current sensor, wherein the second time period is larger than the first time period;
continuously monitoring a current using the first current sensor and the second current sensor;
generating a first signal when the current exceeds the first current threshold for an amount of time that exceeds the first time period;
generating a second signal when the current exceeds the second current threshold for an amount of time that exceeds the second time period; and
providing at least one of the first and second signals to a controller.

19. The method of claim 18 , wherein generating a first signal further comprises generating a first alarm signal indicating the current exceeded the first current threshold for the amount of time that exceeds the first time period and generating a second signal further comprises generating a second alarm signal indicating the current exceeded the second current threshold for the amount of time that exceeds the second time period.

Assignees

• Littelfuse Inc

Inventors

• Riley James

Classifications

• G01R19/16542

  for batteries (charge condition monitoring in G01R31/36) · CPC title

• H02H3/08 Primary

  responsive to excess current (responsive to abnormal temperature caused by excess current H02H5/04) · CPC title

• G01R19/16571 Primary

  comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current (G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533, G01R19/1659 take precedence; measuring currents by using elements sensitive to the magnetic field generated G01R15/14; measuring earth resistance G01R27/18; testing for leakage or short circuits in electrical apparatus G01R31/52) · CPC title

• H02H3/093

  with timing means {(in general H02H3/027; thermal delay H02H3/085; timing means for undervoltage protection H02H3/247)} · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title