Calibratable Multidimensional Magnetic Point Sensor

• US 20110031960A1
• Filed: 08/19/2008
• Published: 02/10/2011
• Est. Priority Date: 08/31/2007
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Stahl-Offergeld, Markus, Hohe, Hans-Peter, Hackner, Michael
• Granted Patent: US 8,203,329 B2
• Time in Patent Office: Days
• US Class Current: 324/202
• CPC Class Codes: G01R 33/0017 Means for compensating offset magnetic fields or the magnetic flux to be measured; Means for generating calibration magnetic fields
• CPC Class Codes: G01R 33/0035 Calibration of single magnetic sensors, e.g. integrated calibration
• CPC Class Codes: G01R 33/07 Hall effect devices
• CPC Class Codes: G01R 33/075 Hall devices configured for spinning current measurements

Abstract

A calibratable magnetic field sensor for sensing a first and a second spatial component of a magnetic field in a reference point, wherein the magnetic field includes a first and a second measurement field component and/or a first and a second calibration field component. The magnetic filed sensor includes a first sensor element arrangement including at least a first and a second sensor element for sensing the first magnetic field component, which includes a first measurement field component and/or a first calibration field component, with respect to a first spatial axis in the reference point. Furthermore, the magnetic field sensor includes a second sensor element arrangement for sensing the second magnetic field component, which includes a second measurement field component and/or a second calibration field component, with respect to a second spatial axis in the reference point. The magnetic filed sensor also includes an excitation line arranged with respect to the first sensor element arrangement so that, when impressing a default current into the excitation line, a pair of different asymmetrical default calibration field components in the first sensor element and in the second sensor element is generated with respect to the first spatial axis in the first sensor element arrangement, wherein the two spatial axes pass along linearly independent position vectors.

Claims

1. A calibratable magnetic field sensor for sensing a first and a second spatial component of a magnetic field in a reference point, wherein the magnetic field comprises a first and a second measurement field component and/or a first and a second calibration field component, comprising:

a first sensor element arrangement comprising at least a first and a second sensor element for sensing the first magnetic field component, which comprises a first measurement field component and/or a first calibration field component, with respect to a first spatial axis in the reference point;

a second sensor element arrangement for sensing the second magnetic field component, which comprises a second measurement field component and/or a second calibration field component, with respect to a second spatial axis in the reference point, wherein the two spatial axes pass along linearly independent position vectors;

an excitation line arranged with respect to the first sensor element arrangement so that, when impressing a default current into the excitation line, a pair of different asymmetrical default calibration field components in the first sensor element and in the second sensor element is generated with respect to the first spatial axis.

2. The calibratable magnetic field sensor according to claim 1, wherein the second sensor element arrangement comprises at least a first and a second sensor element, and the excitation line further is arranged with respect to the second sensor element arrangement so that a second pair of different asymmetrical default calibration field components in the first sensor element and in the second sensor element is generated with respect to the second spatial axis in the sensor element arrangement.

3. The calibratable magnetic field sensor according to claim 1, further formed to sense a third spatial component of the magnetic field in the reference point, wherein the magnetic field further comprises a third measurement field component and/or a third calibration field component, and the magnetic field sensor further comprises a third sensor element arrangement for sensing the third magnetic field component, which comprises the third measurement field component and/or the third calibration field component, with respect to a third spatial axis in the reference point, wherein the three spatial axes pass along linearly independent position vectors.

4. The calibratable magnetic field sensor according to claim 3, wherein the third sensor element arrangement comprises at least a first and a second sensor element, and wherein the excitation line is arranged with respect to the third sensor element arrangement so that, when impressing a default current into the excitation line, a pair of different asymmetrical default calibration field components in the first sensor element and in the second sensor element is generated with respect to the third spatial axis in the third sensor element arrangement.

5. The magnetic field sensor according to claim 1, wherein the excitation line is formed such that it comprises a partial winding.

6. The magnetic field sensor according to claim 5, wherein the excitation line is arranged such that the coil with the at least one winding comprises shortest distances to the at least two sensor elements of a sensor element arrangement, which are different.

7. The magnetic field sensor according to claim 5, wherein the excitation line is arranged symmetrically with respect to the reference point and sweeps the sensor elements of a sensor element arrangement a different number of times.

8. The magnetic field sensor according to claim 1, wherein the excitation line is arranged such that it comprises a coil with at least one complete winding.

9. The magnetic field sensor according to claim 1, further comprising a second excitation line.

10. The magnetic field sensor according to claim 9, wherein the second excitation line is arranged with respect to the first, second or third sensor element arrangement so as to generate a first further pair of different asymmetrical default calibration field components in the first sensor element and in the second sensor element with respect to the first spatial axis in the first sensor element arrangement when impressing a further default current into the second excitation line, to generate a second further pair of different asymmetrical default calibration field components in the first sensor element and in the second sensor element with respect to the second spatial axis in the second sensor element arrangement, or to generate a third further pair of different asymmetrical default calibration field components in the first sensor element and in the second sensor element with respect to the third spatial axis in the third sensor element arrangement.

11. The magnetic field sensor according to claim 10, wherein the first excitation line and the second excitation line are arranged so that the first further pair of different asymmetrical default calibration field components is in an inverse relation with respect to each other relative to the first pair of calibration field components, the second further pair of different asymmetrical default calibration field components is in an inverse relation with respect to each other relative to the second pair of calibration field components, and the third further pair of different asymmetrical default calibration field components is in an inverse relation with respect to each other relative to the third pair of calibration field components.

12. The magnetic field sensor according to claim 1, wherein the second or third sensor element arrangement comprises a hall sensor element horizontal with respect to a main surface of the magnetic field sensor.

13. The magnetic field sensor according to claim 1, wherein the second or third sensor element arrangement comprises a plurality of hall sensor elements horizontal with respect to a main surface of the magnetic field sensor, wherein the geometrical arrangement of the plurality of horizontal hall sensor elements with respect to the reference point is symmetrical in pairs, and the hall sensor elements are coupled to each other such that the magnetic field component can be sensed in an offset-compensated manner.

14. The magnetic field sensor according to claim 1, wherein the first, second or third sensor element arrangement comprises at least two hall sensor elements vertical with respect to a main surface of the magnetic field sensor, wherein the geometrical arrangement of the at least two vertical hall sensor elements with respect to the reference point is symmetrical in pairs, and the same are coupled to each other such that the magnetic field components can be sensed in an offset-compensated manner.

15. The magnetic field sensor according to claim 1, wherein the first, second or third sensor element arrangement can be operated in the spinning current mode.

16. A method for sensing a first and a second spatial component of a magnetic field in a reference point, wherein the magnetic field comprises a first and a second measurement field component and/or a first and a second calibration field component, comprising:

sensing, in a first and a second sensor element of a first sensor element arrangement, a first pair of magnetic field components, which comprise first measurement field components and/or first calibration field components, with respect to a first spatial axis in the reference point;

sensing, in a second sensor element arrangement, second magnetic field components, which comprise second measurement field components and/or second calibration field components, with respect to a second spatial axis in the reference point, wherein the two spatial axes pass along linearly independent position vectors; and

generating a first pair of different asymmetrical calibration field components with respect to the first spatial axis in the first and the second sensor element of the first sensor element arrangement.

17. The method according to claim 16, further comprising:

sensing a second pair of magnetic field components, which comprise second magnetic field components and/or second calibration field components, with respect to the second spatial axis in the reference point; and

generating a second pair of different asymmetrical calibration field components with respect to the second spatial axis.

18. The method according to claim 16, further comprising:

sensing a third spatial component of the magnetic field in the reference point, wherein the magnetic field further comprises a third measurement field component and/or a third calibration field component; and

generating third calibration field components with respect to the third spatial axis, wherein the three spatial axes pass along linearly independent position vectors.

19. The method according to claim 18, further comprising:

sensing a third pair of magnetic field components, which comprise three measurement field components and/or third calibration field components, with respect to the third spatial axis in the reference point; and

generating the third pair of different asymmetrical calibration field components with respect to the third spatial axis.

20. The method according to claim 16, further comprising generating the first, second and third further calibration field components with respect to the first, second and third spatial axes and sensing the first, second and third further magnetic field components, which comprises the first, second and third further measurement field components and/or first, second and third calibration field components.

21. The method according to claim 16, further comprising:

first linearly combining the measurement signals of a magnetic field component, which are associated with the magnetic field components, to a first total measurement value, in order to reduce the influence of the measurement field component in the first total measurement value;

or

second linearly combining the measurement signals of a magnetic field component, which are associated with the further magnetic field components, to a second total measurement value, in order to reduce the influence of the calibration field component in the second total measurement value.

22. The method according to claim 21, wherein first linearly combining the measurement signals of a measurement field component, which is associated with the magnetic field components or the further magnetic field components, to a first total measurement value takes place such that a proportion of the measurement field component in the first total measurement value is reduced to less than 10%, 1% or 0.1% of the first total measurement value.

23. The method according to claim 21, wherein second combining of the measurement signals of a magnetic field component, which are associated with the magnetic field components or the further magnetic field components, to a second total measurement value takes place such that the proportion of the calibration field component in the second total measurement value is reduced to less than 10%, 1% or 0.1% of the second total measurement value.

24. The method according to claim 16, further comprising combining the measurement signals of a magnetic field component, which are associated with the magnetic field components or the further magnetic field components, so that the magnetic field component is sensed in an offset-compensated manner.

25. The method according to claim 16, wherein operating phases are performed in accordance with to a spinning current method.

26. The method according to claim 16, further comprising:

storing excitation current strengths, measurement field components or calibration field components for calibration;

associating the excitation current strengths with calibration field components or magnetic field strengths; and

providing value pairs of measurement field components and magnetic field strengths.

27. A computer program with a program code for performing, when the program code is executed on a computer, a method for sensing a first and a second spatial component of a magnetic field in a reference point, wherein the magnetic field comprises a first and a second measurement field component and/or a first and a second calibration field component, the method comprising:

sensing, in a first and a second sensor element of a first sensor element arrangement, a first pair of magnetic field components, which comprise first measurement field components and/or first calibration field components, with respect to a first spatial axis in the reference point;

sensing, in a second sensor element arrangement, second magnetic field components, which comprise second measurement field components and/or second calibration field components, with respect to a second spatial axis in the reference point, wherein the two spatial axes pass along linearly independent position vectors; and

generating a first pair of different asymmetrical calibration field components with respect to the first spatial axis in the first and the second sensor element of the first sensor element arrangement.