Method and system for calibrating current sensor of electric vehicle battery electronics

• US 9,529,049 B2
• Filed: 12/09/2013
• Issued: 12/27/2016
• Est. Priority Date: 12/09/2013
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Tabatowski-Bush, Benjamin A.
• Primary Examiner(s): PELTON, NATHANIEL R
• Application Number:
  US14/100,739
• Publication Number:
  US 20150160298A1
• Time in Patent Office: 1,114 Days
• Field of Search: 324/426
• US Class Current: 1/1
• CPC Class Codes: G01R 15/183 using transformers with a magnetic core
• CPC Class Codes: G01R 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08
• CPC Class Codes: G01R 27/2611 Measuring inductance
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: G01R 33/07 Hall effect devices
• CPC Class Codes: G01R 33/072 Constructional adaptation of the sensor to specific applications
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence

Abstract

An electric vehicle battery arrangement includes a current sensor. The current sensor has a core and a magnetic field detector. An N-turn coil is wrapped around the core. A controller is configured to adjust an output of the detector indicative of current according to a comparison between a magnetic field caused by a given current in the coil as detected by the detector and a magnetic field expected to be caused by the given current in the coil.

Claims

1. A system comprising:

a core around a conductor;

a N-turns coil wrapped around the core;

a controller to feed the coil with a calibration current, unknown within a known tolerance, of 1/N*a maximum conductor current and to adjust a magnetic field detector output indicative of conductor current according to a comparison between the detector detected and expected magnetic fields caused by the calibration current whereby the output is as accurate as the tolerance.

2. The system of claim 1 wherein:

the conductor extends between a battery and a switch;

the switch is opened and no conductor current is on the conductor while the calibration current is fed to the coil; and

the switch is closed and the calibration current is absent from the coil while conductor current is on the conductor.

3. The system of claim 1 wherein:

the coil is wrapped around a leg of the core.

4. The system of claim 1 wherein:

the magnetic detector is a Hall-effect IC.

5. The system of claim 1 wherein:

the controller is further configured to adjust the calibration current to other values.

6. A method comprising:

providing a current sensor having a core around a conductor, a magnetic field detector, and a N-turn coil wrapped around the core, wherein N is greater than one;

when no current is on the conductor, feeding the coil with a calibration current, unknown within a known tolerance, of 1/N*a maximum current to be detected on the conductor; and

adjusting an output of the detector indicative of current on the conductor according to a comparison between a magnetic field caused by the calibration current in the coil as detected by the detector and a magnetic field expected to be caused by the calibration current in the coil whereby the output of the detector is as accurate as the known tolerance.

7. An electric vehicle comprising:

a battery;

a switch;

a current sensor having a core and a magnetic detector;

a conduction line extending between the battery and the switch and extending through a central opening of the core;

a N-turn coil wrapped around the core, wherein N is greater than one; and

a controller configured to, when no current is on the conduction line, feed the coil with a calibration current, unknown within a known tolerance, of 1/N*a maximum current to be detected on the conduction line and to adjust an output of the detector indicative of current on the conduction line according to a comparison between a magnetic field caused by the calibration current in the coil as detected by the detector and a magnetic field expected to be caused by the calibration current in the coil whereby the output of the detector is as accurate as the known tolerance.

8. The vehicle of claim 7 wherein:

the switch is opened while the calibration current is in the coil.

9. The vehicle of claim 7 wherein:

the switch is closed and calibration current is absent from the coil while current is on the conduction line.

10. The vehicle of claim 7 wherein:

the coil is wrapped around a leg of the core.