US 12,237,730 B2
Magnetic angle sensor system with stray field compensation
Gernot Binder, Klagenfurt (AT); Joao Cunha, Munich (DE); Helmut Koeck, Villach (AT); and Markus Lehner, Munich (DE)
Assigned to Infineon Technologies AG, Neubiberg (DE)
Filed by Infineon Technologies AG, Neubiberg (DE)
Filed on Jun. 3, 2022, as Appl. No. 17/805,378.
Claims priority of application No. 102021205720.9 (DE), filed on Jun. 7, 2021.
Prior Publication US 2022/0393554 A1, Dec. 8, 2022
Int. Cl. H02K 11/215 (2016.01); G01R 33/07 (2006.01); H02K 7/00 (2006.01)
CPC H02K 11/215 (2016.01) [G01R 33/075 (2013.01); H02K 7/003 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A magnetic angle sensor system comprising:
a rotatable shaft,
a permanent magnet coupled to the rotatable shaft,
a magnetic field sensor arranged opposite the permanent magnet, the magnetic field sensor being configured to detect a magnetic field prevailing in a detection region of the magnetic field sensor,
wherein the magnetic field sensor is configured to generate, based on detecting the magnetic field, at least two differential sensor signals with which homogeneous stray field components can be compensated for, and to determine a rotation angle of the rotatable shaft based on the at least two differential sensor signals,
wherein the rotatable shaft comprises a ferromagnetic material, the ferromagnetic material spatially distorting an existing external homogeneous magnetic stray field so that the magnetic field in the detection region of the magnetic field sensor changes in comparison with a situation in which the existing external homogeneous magnetic stray field is not present, wherein a spatial distortion of the existing external homogeneous magnetic stray field due to the ferromagnetic material causes the existing external homogeneous magnetic stray field to include, in addition to one or more homogeneous stray field components, one or more inhomogeneous stray field components of the existing external homogeneous magnetic stray field that leads to measurement errors in the rotation angle of the rotatable shaft determined by the magnetic field sensor, and
a holding device stationary relative to the rotatable shaft and configured to one or more of reduce the inhomogeneous stray field component or compensate for the inhomogeneous stray field component,
wherein the holding device includes a recess in which the magnetic field sensor is arranged,
wherein the holding device is arranged at a distance from the rotatable shaft and coaxially with the rotatable shaft to cause the magnetic field sensor arranged in the holding device to lie opposite to the permanent magnet,
wherein the holding device comprises a soft magnetic material into which magnetic field lines of the existing external homogeneous magnetic stray field, including the one or more inhomogeneous stray field components, penetrate and are guided through the holding device and past the magnetic field sensor without interfering with the magnetic field sensor, and
wherein the holding device is a disc-shaped plate having a center recessed portion and an outer flange that extends radially from the center recessed portion, wherein an inner diameter of the outer flange and the center recessed portion define the recess.