Magnetic position sensor system, method and device with error detection
Method of determining a position of a sensor device relative to a magnetic source, includes: a) determining a first and a second magnetic field component at a first sensor location; b) determining a third and a fourth magnetic field component at a second sensor location; c) determining a first difference of the first and third component, and determining a second difference of the second and fourth component, and determining a first angle based on a ratio of the first and second difference; d) determining a first sum of the first and third component, and determining a second sum of the second and fourth component; e) determining a second angle based on a ratio of said first and second sum; f) comparing the first and second angle to detect error.
1. A position sensor device comprising:
a first sensor configured for determining three magnetic field components Bx1, By1, Bz1 oriented in three orthogonal directions including a first, a second and a third direction, at a first sensor location;
a second sensor configured for determining three magnetic field components Bx2, By2, Bz2 oriented in said three orthogonal directions at a second sensor location spaced from the first sensor location;
a processing unit connected to the first sensor and to the second sensor, and
configured for determining three differences including: a first difference ΔBx between Bx1 and Bx2 a second difference ΔBy between By1 and By2, and a third difference ΔBz between Bz1 and Bz2, and
configured for determining a first angle based on a first ratio of one of the first difference ΔBx, the second difference ΔBy, and the third difference ΔBz to another of the first difference ΔBx, the second difference ΔBy, and the third difference ΔBz, and for outputting the first angle; and
configured for determining a second angle based on a second ratio of one of the first difference ΔBx, the second difference ΔBy, and the third difference ΔBz to another of the first difference ΔBx, the second difference ΔBy, and the third difference ΔBz, the second ratio being different from the first ratio and different from an inverse of the first ratio, and for outputting the second angle.
2. The position sensor device according to claim 1 ,
wherein the first angle is different from the second angle.
3. The position sensor device according to claim 1 ,
wherein the first sensor and the second sensor are integrated in a semiconductor substrate;
wherein one of said three orthogonal directions is perpendicular to the semiconductor substrate, and wherein the two other of said three orthogonal directions are parallel to the semiconductor substrate.
4. The position sensor device according to claim 1 ,
wherein the second sensor location is spaced from the first sensor location by a distance of 1.0 to 3.0 mm.
5. The position sensor device according to claim 1 ,
wherein each of the first and second sensor comprises an integrated magnetic concentrator and four horizontal Hall elements arranged near a periphery of the integrated magnetic concentrator, and angularly spaced by multiples of 90°.
6. The position sensor device according to claim 1 ,
wherein each of the first and second sensor comprises a horizontal Hall element, and two vertical Hall elements arranged such that their axes of maximum sensitivity are perpendicular to each other.
7. A magnetic position sensor system comprising:
the position sensor device according to claim 1 ; and
a magnetic source for generating a magnetic field having at least two poles, the magnetic source being movable relative to said position sensor device.
8. The magnetic position sensor system according to claim 7 ,
wherein the magnetic source is a permanent magnet.
9. The magnetic position sensor system according to claim 7 ,
wherein the magnetic source is rotatable with respect to the position sensor device.
10. The magnetic position sensor system according to claim 7 ,
wherein the position sensor device is mounted at a nonzero distance from the magnetic source.
11. The magnetic position sensor system according to claim 7 ,
wherein the magnet comprises at least two poles.
12. The magnetic position sensor system according to claim 7 ,
wherein the magnet is a two-pole magnet.
13. The magnetic position sensor system according to claim 12 ,
wherein the magnet is magnetized along a magnetization axis;
wherein one of the three orthogonal directions is parallel to the magnetization axis.
14. The magnetic position sensor system according to claim 7 ,
wherein the first and second sensor locations are spaced apart along one of the three orthogonal directions.
15. A method of determining a position of a magnetic source relative to a position sensor device, comprising the steps of:
determining three magnetic field components oriented in three orthogonal directions including a first, a second and a third direction, at a first sensor location;
determining three magnetic field components oriented in said three orthogonal directions, at a second sensor location spaced from the first sensor location;
determining a first difference between a magnetic field component oriented in the first direction from the three magnetic field components determined at the first sensor location and a magnetic field component oriented in the first direction from the three magnetic field components determined at the second sensor location, and a second difference between a magnetic field component oriented in the second direction from the three magnetic field components determined at the first sensor location and a magnetic field component oriented in the second direction from the three magnetic field components determined at the second sensor location, and a third difference between a magnetic field component oriented in the third direction from the three magnetic field components determined at the first sensor location and a magnetic field component oriented in the third direction from the three magnetic field components determined at the second sensor location;
determining a first angle based on a ratio of the first and the third difference, and outputting the first angle;
determining a second angle based on a ratio of the second and the third difference, and outputting the second angle.
16. The method according to claim 15 , wherein the magnet is a two-pole magnet.
17. The method according to claim 15 ,
wherein the magnet is magnetized along a magnetization axis;
wherein one of the three orthogonal directions is parallel to the magnetization axis.
18. The method according to claim 15 ,
wherein the first and second sensor are spaced apart along one of the three orthogonal directions.
19. The method according to claim 15 ,
wherein the second sensor location is spaced from the first sensor location by a distance of 1.0 to 3.0 mm.