Method and Device for Determining a Charge State of a Battery with the Aid of a Fluxgate Sensor

• US 20120191389A1
• Filed: 06/02/2010
• Published: 07/26/2012
• Est. Priority Date: 07/31/2009
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Wenzler, Axel
• Granted Patent: US 9,500,711 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 15/185 with compensation or feedback windings or interacting coils, e.g. 0-flux sensors using galvano-magnetic field sensors G01R15/20; conversion of DC into AC using transductors G01R19/20
• CPC Class Codes: G01R 19/20 using transductors , i.e. a magnetic core transducer the saturation of which is cyclically reversed by an AC source on the secondary side
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC

Abstract

A method for determining the charge state of a battery in a motor vehicle includes steps of applying a measuring voltage to a coil, cyclically reversing the polarity of the measuring voltage if the absolute value of the secondary current flowing through the coil exceeds a predetermined threshold value, scanning the secondary current, reconstructing the curve of the secondary current based on the scanned secondary current values, and determining the charge state based on the curve of the secondary current values.

Claims

1-9. -9. (canceled)

10. A method for determining a charge state of a battery in a motor vehicle, comprising:

applying a measuring voltage to a coil, wherein the coil surrounds a conductive element which is connected to the battery;

cyclically reversing the polarity of the measuring voltage when the absolute value of a secondary current flowing through the coil exceeds a predetermined threshold value;

scanning values of the secondary current;

reconstructing a curve of the secondary current based on the scanned secondary current values; and

determining the charge state of the battery based at least on the curve of the secondary current values.

11. The method as recited in claim 10, wherein the secondary current is scanned more than 2 times per cycle.

12. The method (300) as recited in claim 11, wherein the scannings of the secondary current values are performed at different time intervals.

13. The method (300) as recited in claim 12, wherein the reconstruction of the curve is only based on scanned values from outside a predetermined time range surrounding the points in time of reversing the polarity of the measuring voltage.

14. The method as recited in claim 11, wherein the reconstruction depicts periodic portions of the curve of the secondary current below a predetermined maximum frequency.

15. The method as recited in claim 11, further comprising:

determining points in time of scanning values of the secondary current based on a cycle duration of a preceding measuring cycle.

16. The method as recited in claim 11, wherein the charge state of the battery is additionally determined based on the battery voltage, and wherein the method further comprises:

scanning the battery voltage simultaneously with the secondary current; and

reconstructing a curve of the battery voltage based on the scanned battery voltage values.

17. A device for determining a charge state of a battery in a motor vehicle, comprising:

a measuring voltage source applying a measuring voltage to a coil, wherein the coil surrounds a conductive element which is connected to the battery;

a comparator comparing the absolute value of a secondary current flowing through the coil with a predetermined threshold value;

a reversing device cyclically reversing the polarity of the measuring voltage as a function of the comparison result;

a scanning device scanning the secondary current values;

a processing device reconstructing a curve of the secondary current based on the scanned secondary current values; and

a determination device determining the charge state of the battery based on the curve of the secondary current values.

18. The device as recited in claim 17, further comprising:

a scanning controller controlling the scanning of the secondary current values over time.