Magnetic 3D Sensor Calibratable During Measurement Operation

• US 20120016614A1
• Filed: 06/27/2007
• Published: 01/19/2012
• Est. Priority Date: 08/09/2006
• 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 9,024,622 B2
• Time in Patent Office: Days
• US Class Current: 702/85
• CPC Class Codes: G01R 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08
• 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 33/0206 Three-component magnetometers
• CPC Class Codes: G01R 33/07 Hall effect devices
• CPC Class Codes: G01R 33/075 Hall devices configured for spinning current measurements

Abstract

A magnetic field sensor for detecting first, second, and third spatial components of a magnetic field at a reference point includes a first sensor element arrangement for detecting the first magnetic field component having a first measurement field component and a first calibration field component with respect to a first spatial axis at a reference point, a second sensor element arrangement for detecting the second magnetic field component having a second measurement field component and a second calibration field component with respect to a second spatial axis y at the reference point and a third sensor element arrangement for detecting the third magnetic field component having a third measurement field component and a third calibration field component with respect to a third spatial axis x at the reference point. An excitation line is arranged such with respect to the three sensor element arrangements that when impressing a predetermined current into the excitation line respective predetermined calibration field components with respect to the spatial axes in the sensor element arrangements are generated.

Claims

1. A magnetic field sensor calibratable during measurement operation for detecting first, second, and third spatial components B_z, B_y and B_x of a magnetic field at a reference point, wherein the magnetic field comprises first, second, and third measurement field components B_Mz, B_My and B_Mx, and/or first, second, and third calibration field components B_Kz, B_Ky and B_Kx, comprising:

a first sensor element arrangement for detecting the first magnetic field component B_z comprising a first measurement field component B_Mz and/or a first calibration field component B_Kz, with respect to a first spatial axis z at the reference point;

a second sensor element arrangement for detecting the second magnetic field component B_y comprising a second measurement field component B_My and/or a second calibration field component B_Ky, with respect to a second spatial axis y at the reference point;

a third sensor element arrangement for detecting the third magnetic field component B_x comprising a third measurement field component B_Mx and/or a third calibration field component B_Kx, with respect to a third spatial axis x at the reference point; and

an excitation line arranged such with respect to the first, second, and third sensor element arrangements that when impressing a predetermined current into the excitation line, a first predetermined calibration field component B_Kz with respect to the first spatial axis x in the first sensor element arrangement is generated, a second predetermined calibration field component B_Ky with respect to the second spatial axis y in the second sensor element arrangement is generated, and a third predetermined calibration field component B_Kx with respect to the third spatial axis x in the third sensor element arrangement is generated, wherein the three spatial axes z, y, and x run along linearly independent position vectors.

2. The magnetic field sensor according to claim 1, wherein the first, second and third sensor element arrangements can be operated in a plurality of operating phases, wherein each of the first, second, and third sensor element arrangements is implemented to provide, in every operating phase, a measurement signal attributable to the operating phase.

3. The magnetic field sensor according to claim 2, wherein each of the first, second and third sensor element arrangements is implemented to provide the measurement signals attributed to the operating phases, wherein the measurement signals attributed to the operating phases can be combined to a first total measurement value by a first linear combination, such that the influence of the measurement field component in the first total measurement value is reduced, or the measurement signals attributed to the operating phases can be combined to a second total measurement value by a second linear combination, such that the influence of the calibration field component in the second total measurement value is reduced.

4. The magnetic field sensor according to claim 3, wherein the measurement signals attributed to the operating phases can be combined to a first total measurement value by a first linear combination, such that the influence 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.

5. The magnetic field sensor according to claim 3, wherein the measurement signals attributed to the operating phases can be combined to a second total measurement value by a second linear combination, such that the portion 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.

6. The magnetic field sensor according to claim 1, wherein the first sensor element arrangement comprises a Hall sensor element horizontal with respect to a main surface of the magnetic field sensor.

7. The magnetic field sensor according to claim 1, wherein the first 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 is symmetrical in pairs with respect to the reference point and the Hall sensor elements are coupled to each other such that the magnetic field component can be detected in an offset-compensated manner.

8. The magnetic field sensor according claim 1, wherein the second 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 is symmetrical in pairs with respect to the reference point, and that are coupled to each other such that the magnetic field component can be detected in an offset-compensated manner.

9. The magnetic field sensor according to claim 1, wherein the 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 is symmetrical in pairs with respect to the reference point, and that are coupled to each other such that the magnetic field component can be detected in an offset-compensated manner.

10. The magnetic field sensor according to claim 1, wherein the first, second and third sensor element arrangements can be operated in the spinning current mode.

11. A method for calibrating a magnetic field sensor during measurement operation by detecting first, second, and third spatial components B_z, B_y and B_x of a magnetic field at a reference point, wherein the magnetic field comprises first, second, and third measurement field components B_Mz, B_My, B_Mx and/or first, second, and third calibration field components B_Kz, B_Ky and B_Kx, comprising:

detecting the first magnetic field component B_z comprising a first measurement field component B_Mz and/or a first calibration field component B_Kz with respect to the first spatial axis z at the reference point;

detecting the second magnetic field component B_y comprising a second measurement field component B_My and/or a second calibration field component B_Ky with respect to the second spatial axis y at the reference point;

detecting the third magnetic field component B_x comprising a third measurement field component B_My and/or a third calibration field component B_Kx with respect to the third spatial axis x at the reference point; and

generating the first, second, and third calibration field components B_Kz, B_Ky and B_Kx with respect to the first, second, and third spatial axes z, y and x, wherein the first, second, and third spatial axes run along a linearly independent position vector.

12. The method according to claim 11, wherein the steps of detecting are repeated during a plurality of operating phases, wherein measurement signals attributed to the first magnetic field component B_z, to the second magnetic field component B_y, and to the third magnetic field component B_x in the operating phases are detected.

13. The method according to claim 11, further comprising first linearly combining the measurement signals of a magnetic field component attributed to the operating phases to a first total measurement value, such that the influence of the measurement field component in the first total measurement value is reduced, or second linearly combining the measurement signals of a magnetic field component attributed to the operating phases to a second total measurement value, such that the influence of the measurement field component in the second total measurement value is reduced.

14. The method according to claim 13, wherein first linearly combining the measurement signals of a magnetic field component attributed to the operating phases to a first total measurement value is performed such that a portion 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.

15. The method according to claim 13, wherein second combining the measurement signals of a magnetic field component attributed to the operating phases to a second total measurement value is performed such that the portion 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.

16. The method according to claim 11, further comprising combining the measurement signals of a magnetic field component attributed to the operating phases, such that the magnetic field component can be detected in an offset-compensated manner.

17. The method according to claim 11, wherein the operating phases are implemented according to a spinning current method.

18. The method according to claim 11, further comprising:

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

attributing the excitation current strength to the calibration field components or magnetic field strengths, respectively; and

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

19. A computer program comprising a program code for performing the method for calibrating a magnetic field sensor during measurement operation by detecting first, second, and third spatial components B_z, B_y and B_x of a magnetic field at a reference point, wherein the magnetic field comprises first, second, and third measurement field components B_Mz, B_My, B_Mx and/or first, second, and third calibration field components B_Kz, B_Ky and B_Kx, comprising:

detecting the first magnetic field component B_Z comprising a first measurement field component B_Mz and/or a first calibration field component B_KZ with respect to the first spatial axis z at the reference point;

detecting the second magnetic field component B_y comprising a second measurement field component B_My and/or a second calibration field component B_Ky with respect to the second spatial axis y at the reference point;

detecting the third magnetic field component B_x comprising a third measurement field component B_My and/or a third calibration field component B_Kx with respect to the third spatial axis x at the reference point; and

generating the first, second, and third calibration field components B_Kz, B_Ky and B_Kx with respect to the first, second, and third spatial axes z, y and x, wherein the first, second, and third spatial axes run along a linearly independent position vector, when the program code runs on a computer.