Magnetic sensor device, system and method

Patent metadata

Field	Value
Publication number	US-12111185-B2
Application number	US-202217750114-A
Country	US
Kind code	B2
Filing date	May 20, 2022
Priority date	Aug 22, 2019
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

Angular position sensor system comprising: a cylindrical magnet rotatable about a rotation axis; and an angular position sensor device comprising: a substrate comprising a plurality of magnetic sensitive elements configured for measuring a first magnetic field component in a first direction and a second magnetic field component in a second direction perpendicular to the first direction; and a processing circuit configured for calculating the angular position; the sensor device being oriented such that the first direction is oriented in a circumferential direction, and the second direction is either parallel or orthogonal to the rotation axis; the sensor device being located at a predefined position where a magnitude of a third magnetic field component orthogonal to the first and second magnetic field component is negligible over the 360° angular range.

First claim

The invention claimed is:

1. A method of determining a position of a sensor device relative to a permanent magnet, the sensor device having a substrate comprising a plurality of magnetic sensitive elements, the permanent magnet configured for generating a magnetic field, the method comprising:
measuring at a first sensor location a first magnetic field component oriented in a first direction parallel to the substrate, and a second magnetic field component oriented in a second direction perpendicular to the first direction;
measuring at a second sensor location spaced from the first sensor location along the first direction, a third magnetic field component oriented in said first direction, and a fourth magnetic field component oriented in said second direction;
determining a first magnetic field gradient based on the first and the third magnetic field component;
determining a second magnetic field gradient based on the second and the fourth magnetic field component; and
calculating the position of the sensor device based on said first magnetic field gradient and said second magnetic field gradient;
wherein the first sensor location and the second sensor location are spaced from the permanent magnet in a radial direction of the permanent magnet, and/or
wherein the second direction is perpendicular to the substrate.

2. The method according to claim 1 , wherein the second magnetic field component is parallel to the substrate; and
wherein the fourth magnetic field component is parallel to the substrate.

3. The method according to claim 2 , wherein the sensor device comprises a first integrated magnetic concentrator structure (IMC) located at the first sensor location and a first set of four horizontal Hall element arranged at a circumference of the first IMC and angularly spaced apart by 90°;
wherein the first magnetic field component is determined based on a difference of signals obtained from a first pair of two horizontal Hall elements selected from the first set, and wherein the second magnetic field component is determined based on a difference of signals obtained from a second pair of two horizontal Hall elements selected from the first set, different from the first pair;
wherein the sensor device comprises a second IMC located at the second sensor location and a second set of four horizontal Hall element arranged at a circumference of the second IMC and angularly spaced apart by 90°; and
wherein the third magnetic field component is determined based on a difference of signals obtained from a third pair of two horizontal Hall elements selected from the second set, and wherein the fourth magnetic field component is determined based on a difference of signals obtained from a fourth pair of two horizontal Hall elements selected from the second set, different from the third pair.

4. The method according to claim 2 ,
wherein the sensor device comprises, at the first sensor location, a first vertical Hall element configured for measuring the first magnetic field component, and a second vertical Hall element configured for measuring the second magnetic field component, and at the second sensor location, a third vertical Hall element configured for measuring the third magnetic field component, and a fourth vertical Hall element configured for measuring the fourth magnetic field component;
or wherein the sensor device comprises, at the first sensor location, a first magneto-resistive element configured for measuring the first magnetic field component, and a second magneto-resistive element configured for measuring the second magnetic field component, and at the second sensor location, a third magneto-resistive element configured for measuring the third magnetic field component, and a fourth magneto-resistive element configured for measuring the fourth magnetic field component.

5. The method according to claim 1 , wherein the second magnetic field component is perpendicular to the substrate; and
wherein the fourth magnetic field component is perpendicular to the substrate.

6. The method according to claim 5 , wherein the sensor device comprises a first integrated magnetic concentrator structure (IMC) located at the first sensor location and a first and a second horizontal Hall element arranged at a circumference of the first IMC and angularly spaced apart by 180°;
wherein the first magnetic field component is determined based on a difference of signals obtained from the first and the second horizontal Hall element, and wherein the second magnetic field component is determined based on a sum of the signals obtained from the first and the second horizontal Hall element;
wherein the sensor device further comprises a second IMC located at the second sensor location and a third and a fourth horizontal Hall element arranged at a circumference of the second IMC and angularly spaced apart by 180°; and
wherein the third magnetic field component is determined based on a difference of signals obtained from the third and the fourth horizontal Hall element, and wherein the fourth magnetic field component is determined based on a sum of the signals obtained from the third and the fourth horizontal Hall element.

7. The method according to claim 5 , wherein the sensor device comprises a first integrated magnetic concentrator structure (IMC) located at the first sensor location and a first set of four horizontal Hall elements arranged at a circumference of the first IMC and angularly spaced apart by 90°;
wherein the first magnetic field component is determined based on a difference of signals obtained from a first pair of two horizontal Hall elements selected from the first set, and wherein the second magnetic field component is determined based on a sum of signals obtained from a second pair of two horizontal Hall elements selected from the first set, different from the first pair;
wherein the sensor device further comprises a second IMC located at the second sensor location and a second set of four horizontal Hall elements arranged at a circumference of the second IMC and angularly spaced apart by 90°; and
wherein the third magnetic field component is determined based on a difference of signals obtained from a third pair of two horizontal Hall elements selected from the second set, and

wherein the fourth magnetic field component is determined based on a sum of signals obtained from a fourth pair of two horizontal Hall elements selected from the second set, different from the third pair.

8. The method according to claim 1 ,
wherein the first, second, third and fourth magnetic field component are measured at a predefined axial and radial position relative to the magnet where a magnitude of a third magnetic field component of the magnetic field generated by the magnet, and orthogonal to the first magnetic field component and orthogonal to the second magnetic field component, has a magnitude smaller than 20% of a magnitude of the first magnetic field component and/or of a magnitude of the second magnetic field component.

9. The method according to claim 1 , wherein the magnet is a cylindrical magnet rotatable about a rotation axis; and
wherein the position is an angular position about said rotation axis.

10. The method according to claim 9 , wherein the magnet has an outer radius Ro; and
wherein the first sensor location and the second sensor location are situated at an axial distance below a bottom surface or above a top surface of the magnet in a range from 1.0 to 5.0 mm, and at a radial distance in a range from Ro−7 mm to Ro+7 mm, or in a range from Ro−7 mm to Ro−1 mm, or in a range from Ro+1 mm to Ro+7 mm.

11. The method according to claim 9 , wherein the magnet is a ring magnet having an

Assignees

• Melexis Tech Sa

Inventors

• Dupre Nicolas
• Tombez Lionel
• Close Gael
• Bidaux Yves
• Goyvaerts David

Classifications

• G01B7/30 Primary

  for measuring angles or tapers; for testing the alignment of axes · CPC title

• G01D3/036

  on measuring arrangements themselves · CPC title

• G01D5/145 Primary

  influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06) · CPC title