Magnetic field sensor arrangement, magnetic torque sensor arrangement and method for determining the stray field immunity of a magnetic flux

Abstract

A magnetic field sensor arrangement (220) for determining a signal magnetic flux in a substantially stray-field immune manner, comprising: a signal magnetic field source (S1); a first flux concentrator and a second flux concentrator, with an air gap (203) formed between outer faces (204, 205) of the flux concentrators; the flux concentrators being configured to direct the signal magnetic flux in the gap direction (206) to and through the air gap (203); a magnetic field sensor (207) arranged inside the air gap (203) and configured to measure a first signal and a second signal (Bx, Bz) in the gap direction and perpendicular to the gap direction; and for reducing or eliminating a magnetic interference field based on the first signal and the second signal (Bx, Bz). An angle sensor arrangement. A torque sensor. A method for measuring a signal magnetic flux, an angle, and a torque in a substantially stray-field immune manner.

Description

Field of the Invention

[0001] The present invention generally relates to the field of magnetic field sensor arrangements, and more particularly to magnetic field sensor arrangements for determining the magnetic flux generated by a magnetic field source while being substantially immune to magnetic interference or stray fields generated by another magnetic field source. The present invention also relates to magnetic torque sensor arrangements that are immune to magnetic interference or stray fields. In addition, the present invention relates to a method that is immune to stray fields for determining the magnetic flux generated by a magnetic field source while being substantially immune to magnetic interference or stray fields generated by another magnetic field source. Background Art

[0002] Magnetic sensor systems, particularly linear position sensor systems and angle / rotation position sensor systems, are known in the art. They offer the advantage that linear or angular position can be measured without physical contact by means of a magnetic field sensor arrangement, thereby avoiding problems such as mechanical wear, scratching, friction, etc.

[0003] For example, the measurement of the rotational angle is required in various applications such as the position and / or torque detection of a manual electrical switch or a motor shaft, a valve, etc.

[0004] For example, from DE 102 22 118 A1, a magnetic sensor system for determining the torque applied to a vehicle steering column is known, including a magnetic field sensor arrangement by which the angular displacement between an input shaft portion and an output shaft portion of the steering column is determined using a magnetic field. The magnetic field to be measured and representing the angular displacement between the two shaft portions is generated by a magnetic field source, for example, a (multipole) permanent toroidal magnet that is (directly or indirectly) rotationally fixed to one of the input shaft and the output shaft. The magnetic flux of the generated magnetic field is received and guided by two suitably shaped magnetic flux concentrators, one of which is rotationally fixed to the input shaft and the other is rotationally fixed to the output shaft. The magnetic field sensor measures the magnetic flux in the air gap formed between the two magnetic flux concentrators, where the magnetic flux in the air gap varies as a function of the angular displacement between the input shaft portion and the output shaft portion.

[0005] EP3505894 describes a torque sensor including a multipole toroidal magnet and two magnetic yokes respectively connected to an input shaft and an output shaft. These yokes have protrusions that form an air gap. A sensor device is placed in this air gap for measuring the change in magnetic flux density indicating the angular displacement between the two yokes, which angular displacement itself indicates the torque applied to the input shaft and the output shaft. This torque sensor is designed to reduce or eliminate assembly errors but is not immune to external interference fields.

[0006] With the increasing compactness of electrical systems, especially in motor vehicles with hybrid engines or in electric trains, such magnetic sensor systems are often additionally exposed to an external magnetic field from nearby current conductors carrying strong currents (e.g., exceeding 100 A). Such an external magnetic field (also referred to herein as an (external) magnetic interference field or an (external) magnetic stray field) generated by an external magnetic field source (also referred to herein as an interference magnetic field source), e.g., the above-mentioned current conductor passing near the actual magnetic sensor system, can corrupt the measured values determined by the sensor system, thereby degrading the accuracy of the linear position or angular / rotational position to be determined.

[0007] Establishing a magnetic sensor system that is substantially immune (i.e., substantially insensitive) to such external magnetic interference fields or external magnetic stray fields is a challenge.

[0008] There is always room for improvement or alternatives. SUMMARY OF THE INVENTION

[0009] An object of embodiments of the present invention is to provide a magnetic field sensor arrangement and a method for determining a magnetic flux (e.g., a magnetic flux generated by a magnetic field source and modulated by a magnetic structure), while being substantially immune to an (external) magnetic interference field, particularly to a substantially uniform magnetic interference field.

[0010] An object of embodiments of the present invention is to provide an angular sensor arrangement and a method for determining an angular displacement in a manner that is substantially immune to an (external) magnetic interference field, particularly to a substantially uniform magnetic interference field.

[0011] An object of embodiments of the present invention is to provide a magnetic torque sensor arrangement and a method for determining a torque in a manner that is substantially immune to an (external) magnetic interference field, particularly to a substantially uniform magnetic interference field.

[0012] An object of embodiments of the present invention is to provide a magnetic sensor arrangement and / or an angular sensor arrangement and / or a magnetic torque sensor arrangement that is adapted to provide highly accurate measurement results (e.g., angular displacement, and / or torque measurement) even in the presence of an (external) magnetic interference field, and a method having the same characteristics for determining a magnetic flux immune to stray fields.

[0013] An object of embodiments of the present invention is to provide magnetic sensor arrangements and magnetic torque sensor arrangements having a compact construction, and thus only requiring a small installation space.

[0014] An object of embodiments of the present invention is to provide a magnetic sensor arrangement, a magnetic torque sensor arrangement, and a method for stray-field immune determination of magnetic flux, which only require relatively simple arithmetic operations (such as addition, subtraction, multiplication, division, look-up tables, interpolation) that can be performed on a simple microprocessor or microcontroller, but do not include a discrete Fourier transform (DFT) or a fast Fourier transform (FFT) that typically requires a digital signal processor (DSP) and usually also requires a considerable amount of storage capacity (e.g., RAM, ROM, flash memory, etc.).

[0015] An object of embodiments of the present invention is to provide a torque sensor for measuring the torque applied to an input shaft and an output shaft in a manner highly insensitive to a uniform interference field.

[0016] According to embodiments of the present invention, these and other objects are achieved by a magnetic field sensor arrangement for stray-field immune determination of magnetic flux, a magnetic torque sensor arrangement for stray-field immune determination of torque, and a method for stray-field immune determination of magnetic flux.

[0017] Note that the various features listed in the following description can be combined with each other in any technically meaningful way and illustrate further embodiments of the present invention. The description of the present invention is also characterized and illustrated in particular in conjunction with the accompanying drawings.

[0018] Furthermore, it should be noted that the conjunction "and / or" used herein to combine a first feature and a second feature should always be interpreted as disclosing a first embodiment of the present invention that can include only the first feature, a second embodiment of the present invention that can include only the second feature, and a third embodiment of the present invention that can include both the first feature and the second feature.

[0019] According to a first aspect, the present invention provides a magnetic field sensor arrangement for determining a signal magnetic flux generated by a signal magnetic field source in a manner substantially immune to magnetic interference fields; the magnetic field sensor arrangement comprising: the signal magnetic field source; a first flux concentrator and a second flux concentrator configured and arranged such that an air gap is formed between an outer face of the first flux concentrator and an outer face of the second flux concentrator, wherein the first outer face and the second outer face define a first direction of the air gap by a line of the shortest distance between the outer faces; wherein the first flux concentrator and the second flux concentrator are configured to direct the signal magnetic flux generated by the signal magnetic field source substantially in the first direction to and through the air gap; a magnetic field sensor comprising a plurality of sensor elements arranged inside the air gap; wherein the magnetic field sensor is configured to measure a first signal indicative of a magnetic field component oriented in the first direction, and to measure a second signal indicative of a magnetic field component oriented in a second direction substantially perpendicular to the first direction; and wherein the magnetic field sensor is further configured to reduce or substantially eliminate the influence of the magnetic interference field based on the first signal and the second signal if the magnetic interference field is present.

[0020] The two outer faces are respectively the corresponding outer faces of the first flux concentrator and the second flux concentrator, and the distance between the two outer faces is the smallest. Or in other words, between the surface regions of the first flux concentrator and the second flux concentrator, an "air gap" is formed at the position where the distance between the first flux concentrator and the second flux concentrator is the smallest (since this is where most of the magnetic flux lines will pass). The "gap direction" of the air gap is defined by the line of the shortest length (or reduced distance) between the two outer faces (i.e., the outer face of the first flux concentrator and the outer face of the second flux concentrator that form and delimit the air gap with respect to at least one spatial direction).

[0021] Although the flux concentrators are "intended" to only direct the magnetic flux generated by the signal magnetic source (e.g., a multi-pole ring magnet), in practice, in the presence of an external interference field, the first flux concentrator and the second flux concentrator will also receive and direct a first portion of the external magnetic interference field in the first direction through the gap, which will affect the first signal. A second portion of the interference field passes through the air gap from a direction different from the gap direction (e.g., substantially perpendicular to the gap direction), or from a direction whose line of sight - at least in the region of the cross-section of the air gap traversed by the second interfering magnetic flux - is not blocked by either the first flux concentrator or the second flux concentrator. Thus, although the second portion of the interfering magnetic flux may be slightly affected by the presence of the first flux concentrator and / or the second flux concentrator near the air gap, it is by no means received by the first flux concentrator and the second flux concentrator and directed through the air gap in the gap direction within the first flux concentrator and the second flux concentrator.

[0022] Importantly, the magnetosensitive elements of the sensor device are arranged inside the air gap such that they are able to sense the "signal magnetic flux and the first interfering magnetic flux" in the first sensing direction, and the "second interfering magnetic flux" in the sensing direction. "Being arranged in the air gap" means that the sensor device is arranged such that all its magnetosensitive elements (e.g., Hall plates) are located inside the "virtual channel", through which most of the magnetic flux is transferred from the first magnetic flux conductor to the second magnetic flux conductor. This "virtual channel" is located between the first outer surface and the second outer surface.

[0023] Or in other words, the sensor device is adapted to measure the superposition of the desired magnetic flux (e.g., originating from a magnet) in the first direction and the (undesired) "first part" of the interfering field, and is adapted to measure the "second part" of the interfering field in the second direction. The first part and the second part are related to each other, e.g., proportional to each other. The measurement of the second part can be used to estimate the first part, and then the first part can be subtracted from the measured signal in order to determine the (desired) signal magnetic flux. Depending on the application, the "signal magnetic flux" can indicate a linear position or an angular position. Even in the presence of a magnetic interfering field, the signal magnetic flux or the linear position or the angular position can be determined more accurately by reducing or substantially eliminating the influence from the interfering field.

[0024] An important advantage of the magnetic field sensor arrangement according to the present invention is that the magnetic field sensor is arranged in the air gap such that it can sense, in a first sensing direction of the magnetic field sensor, both the signal magnetic flux and the first interference magnetic flux (or "first part") that enter and pass through the air gap in their superposed state substantially in the gap direction through the gap defining the outer surface between two flux concentrators, and can simultaneously sense, in a second sensing direction of the magnetic field sensor, a second interference magnetic flux (or "second part") that enters the air gap from a spatial direction different from the gap direction (e.g., substantially perpendicular to the gap direction) independent of the signal magnetic flux. Because of this, the amount of the external interference magnetic flux (i.e., the interference magnetic flux present around the actual magnetic field sensor arrangement at a given time) can be determined by the magnetic field sensor in its second sensing direction, thus facilitating the determination of the amount of the first interference magnetic flux of the superposed signal magnetic flux in the first flux concentrator and the second flux concentrator sensed by the magnetic field sensor in its first sensing direction. Knowing the actual amount of the first interference magnetic flux makes it possible to eliminate (or at least substantially suppress) the influence of the external interference magnetic field generated by the interference magnetic field source from the total magnetic flux (signal magnetic flux and first interference magnetic flux) sensed in the first sensing direction, thereby facilitating the determination of the true signal magnetic flux received by the first flux concentrator and the second flux concentrator and guided within the first flux concentrator and the second flux concentrator. As a result, it facilitates isolating the amount of interference generated by the interference magnetic field source, such that the magnetic field sensor arrangement according to the present invention is substantially insensitive or immune to external magnetic stray fields / interference fields.

[0025] Or, in other words, by measuring the "second part" of the interference field, e.g., in a direction substantially perpendicular to the gap direction, the magnitude of the "first part" of the interference field can be determined or at least estimated. By subtracting this estimated first part, the influence from the interference field can be significantly reduced or even completely eliminated. This is especially true for a uniform interference field.

[0026] An advantage of the magnetic field sensor arrangement according to the present invention is that the determination of the signal magnetic flux is substantially insensitive to external magnetic stray fields / interference fields, resulting in considerably more accurate measurement and determination results.

[0027] Or, more specifically formulated for a sensor arrangement for measuring torque, the advantage lies in being able to determine the torque with higher accuracy in a manner that is less sensitive (e.g., substantially insensitive) to magnetic interference fields, especially uniform interference fields.

[0028] Furthermore, an advantage of the magnetic field sensor arrangement according to the invention is that a relatively simple controller (e.g., a microcontroller) can be used to determine the signal magnetic flux, and a powerful processor is not required, since the operations required to determine the signal magnetic flux can be based, for example, on basic operations such as addition, subtraction, multiplication, division, angular functions, and / or look-up tables, but do not require, for example, a discrete Fourier transform (DFT). It should be noted that the angular functions themselves can also be performed using look-up tables and optional interpolation.

[0029] A further advantage of the magnetic field sensor arrangement according to the invention is that stray field immunity is achieved by the new arrangement and / or orientation of the first flux concentrator, the second flux concentrator, and the magnetic field sensor, in particular by orienting the air gap and the gap direction in the manner disclosed herein such that, on the one hand, the signal magnetic flux (e.g., generated by a multipole magnet) combined with the first interference magnetic flux (e.g., the first part of an interference field (e.g., a substantially uniform interference field)), and on the other hand, the separate second interference magnetic flux (e.g., the second part of the interference field) pass through the air gap independently of each other in two different spatial directions, which facilitates a highly compact design that requires only a small installation space. In a preferred embodiment, the sensor device is implemented on a single semiconductor substrate disposed in the air gap.

[0030] The expression "substantially perpendicular" should be understood to include an angular dimension of 90° as well as minor deviations from 90°, which are within the common tolerances consistent with the manufacture of the magnetic field sensor and are thus not the result of targeted actions. Such deviations can include an angular range between approximately 85° and 95°, preferably between 87° and 93°, and more preferably between 89° and 91°.

[0031] An advantage of the invention is that, based on the first magnetic field component and the second magnetic field component measured in the first direction and the second direction, the second signal can be used to reduce or substantially eliminate the first part of the external interference field.

[0032] Without loss of generality and not limited thereto, the interfering magnetic field can be generated by a current-carrying wire. Although strictly speaking, the magnetic field created by this current does not create a uniform field, in practice, at a sufficient distance from the conductor (e.g., at least 10 cm or at least 20 cm from the current-carrying conductor), the magnetic interference field can be considered "substantially uniform". In other words, in addition to the magnetic flux provided by a magnetic source (e.g., a permanent magnet), the first part of the interference field is also received by the first flux concentrator and the second flux concentrator and is guided together with the signal magnetic flux within the first flux concentrator and the second flux concentrator, thus obscuring the actual signal magnetic flux.

[0033] The advantage of the arrangement of magnetic field sensors with a first sensing direction that is substantially aligned with the gap direction is that this facilitates (on the one hand) the magnetic field sensors to sense independently of each other the signal magnetic flux superimposed by the first interfering magnetic flux in the first sensing direction (equal to the gap direction) and (on the other hand) the second interfering magnetic flux in the second sensing direction, and provides a measurement signal that is as high as possible. Thus, the measurement accuracy of the magnetic field sensor arrangement according to the present embodiment is further improved.

[0034] In an embodiment, the magnetic field sensor is configured to reduce or substantially eliminate the influence of the magnetic interference field, if present, by scaling the second signal with a predefined constant and by subtracting the scaled signal from the first signal.

[0035] This function can be implemented in an analog circuit or a digital circuit. The processing circuit is preferably also embedded in the same magnetic field sensor, preferably on the same semiconductor substrate. Note that the processing circuit can, but does not need to, be located inside the air gap. It is sufficient for the magnetosensitive element to be inside the air gap.

[0036] In an embodiment, the magnetic field sensor further includes a processor unit and a memory unit.

[0037] Note that before subtracting the unamplified external second interfering magnetic flux sensed in the second sensing direction, a specific magnetic gain (magnetic amplification) caused by the magnetic flux concentrator that guides the first interfering magnetic flux can be considered. Such an amplification factor between the first interfering magnetic flux and the second interfering magnetic flux can be determined by calibration or parameterization of the magnetic field sensor arrangement and can be stored in the non-volatile memory of the memory unit afterwards (e.g., during production or during the calibration process). Integrating the processor unit and the memory unit together with the magnetic sensor on a single semiconductor substrate further improves the compact design of the magnetic field sensor arrangement according to the present invention.

[0038] According to a second aspect, the present invention provides an angle sensor arrangement, comprising: a magnetic field sensor arrangement according to the first aspect; a first ring including a plurality of claws, the first ring being arranged adjacent to the first magnetic flux concentrator; a second ring including a plurality of claws, the second ring being arranged adjacent to the second magnetic flux concentrator; the first ring and the second ring being movable about a rotation axis and movable relative to each other; and wherein the magnetic field sensor is further configured to convert the signal magnetic flux into an angular distance signal indicating the angular distance between the first ring and the second ring.

[0039] Note that with respect to the effects and advantages of the features of the angle sensor arrangement disclosed herein, reference is generally made to the corresponding similar features of the magnetic field sensor arrangement disclosed herein and their effects and advantages.

[0040] The signal magnetic field source can be a multi-pole toroidal magnet. The toroidal magnet can be radially magnetized. The first ring and the second ring can be rotatable relative to each other about a rotation axis. The first ring and the second ring can have a plurality of protrusions or pads or claws extending axially. These protrusions or pads or claws can have a geometry corresponding to the geometry of the multi-pole toroidal magnet, particularly in terms of the number of poles and the number of pads. For example, they are similar or identical to those described in DE10222118A1 or EP3505894A1. When the first ring rotates relative to the second ring, the magnetic flux generated by the signal source is modulated as a function of the angular displacement. The toroidal magnet can be fixedly (directly or indirectly) connected to one of the rings.

[0041] In an embodiment, the magnetic field sensor is configured to measure a first magnetic field component in a radial direction relative to the rotation axis; and wherein the magnetic field sensor is configured to measure a second magnetic field component in an axial direction parallel to the rotation axis.

[0042] In an embodiment, the outer face of the first magnetic flux concentrator is provided on a part of the first magnetic flux concentrator that has a protrusion or a curved portion or an L-shaped cross-section in a plane containing the rotation axis and a first direction (or gap direction).

[0043] In a further or another embodiment, the outer face of the second magnetic flux concentrator is provided on a part of the second magnetic flux concentrator that has an L-shaped cross-section in a plane containing the rotation axis and a first direction (or gap direction).

[0044] It should be understood that the corresponding parts of the first magnetic flux concentrator and / or the second magnetic flux concentrator that provide the corresponding outer faces defining the air gap relative to the gap direction can also be referred to as the parts of the corresponding magnetic flux concentrators that are near or adjacent to the air gap. The relevant cross-sections are taken from the intersecting plane in the direction of the gap direction.

[0045] In an embodiment, the L-shaped part of the first magnetic flux concentrator and / or the second magnetic flux concentrator includes a long leg and a short leg, where the long leg is longer than the short leg, and where the long leg is oriented substantially perpendicular to the gap direction.

[0046] Regarding the meaning of the expression "substantially perpendicular", reference is made to the explanation set forth above, which is correct throughout the specification. Similarly, according to the present invention, the relative term "longer" should be interpreted such that the length difference between the long leg and the short leg is definitely not within the common tolerances consistent with the manufacture of the first magnetic flux concentrator and / or the second magnetic flux concentrator, but is the result of a targeted action. As an example, the long leg can be at least 10% or at least 20% longer than the short leg.

[0047] According to the above L-shaped configuration and arrangement, the second interfering magnetic flux can reach and pass through the air gap substantially perpendicular to the direction of the gap without being received by the first magnetic flux concentrator and / or the second magnetic flux concentrator, and in particular, not being guided within the first magnetic flux concentrator and / or the second magnetic flux concentrator. If any, the first magnetic flux concentrator and / or the second magnetic flux concentrator, in particular the L-shaped portions of the first magnetic flux concentrator and / or the second magnetic flux concentrator, affect the second interfering magnetic flux in at most an insignificant manner. Therefore, the line of sight in the direction in which the second interfering magnetic flux enters and passes through the air gap is not blocked by the first magnetic flux concentrator and / or the second magnetic flux concentrator. Thus, it is facilitated for the magnetic field sensor to accurately sense / measure / determine the second magnetic interference flux that exists and extends outside the first magnetic flux concentrator and the second magnetic flux concentrator.

[0048] In an embodiment, the outer face of the first magnetic flux concentrator is provided on the portion of the first magnetic flux concentrator that forms the free end of the first magnetic flux concentrator.

[0049] In an embodiment, the outer face of the second magnetic flux concentrator is provided on the portion of the second magnetic flux concentrator that forms the free end of the second magnetic flux concentrator.

[0050] In this way, an improved control is achieved over the direction of the magnetic flux (signal magnetic flux and first interfering magnetic flux) guided by the first magnetic flux concentrator and / or the second magnetic flux concentrator and guided within the first magnetic flux concentrator and / or the second magnetic flux concentrator into the air gap, that is, preferably substantially oriented in the direction of the gap. As described above, the direction of the gap is preferably substantially oriented in a plane perpendicular to the axis of the magnetic arrangement. The direction of the gap can be, for example, substantially oriented radially. If the above input axis and output axis exist, this axis can be parallel to the above input axis and output axis. Thus, an increased concentration of the magnetic flux passing through the air gap between the outer face of the first magnetic flux concentrator and the outer face of the second magnetic flux concentrator is achieved.

[0051] In an embodiment, the outer face of the first magnetic flux concentrator is provided on the portion of the first magnetic flux concentrator that includes at least one fin-shaped extension member.

[0052] In an embodiment, the outer face of the second magnetic flux concentrator is provided on the portion of the second magnetic flux concentrator that includes at least one fin-shaped extension member, wherein the at least one fin-shaped extension member extends beyond the width and / or height of the cross-section of the air gap in a direction substantially perpendicular to the first direction, and wherein the cross-section of the air gap extends substantially perpendicular to the first direction.

[0053] The advantage of this embodiment is that the at least one extension member provides an even further improved control of the direction of external interfering magnetic flux that originates from an interfering magnetic field source and enters the air gap from the outside, where the external interfering magnetic flux is sensed by the magnetic field sensor through its second sensing direction. In addition, depending on the spatial extent of the fin-shaped extension member, it can provide a certain shielding effect (if so desired) to prevent interfering magnetic flux other than the first and second interfering magnetic fluxes and originating from a spatial direction perpendicular to the direction of the second interfering magnetic flux from being sensed by the magnetic field sensor in the air gap, although this magnetic flux basically does not impair the signal magnetic flux to be determined by the angular sensor arrangement (e.g., as part of a torque sensor). Therefore, the accuracy of determining the signal magnetic flux is further improved.

[0054] In an embodiment, the magnetic field sensor includes a semiconductor substrate that is substantially located inside the air gap, and the semiconductor substrate is oriented such that the axis is perpendicular to the semiconductor substrate, and wherein the semiconductor substrate includes an integrated magnetic concentrator (IMC) and at least two horizontal Hall elements arranged at the periphery of the IMC.

[0055] In an embodiment, the magnetic field sensor includes a semiconductor substrate that is substantially located inside the air gap, and the semiconductor substrate is oriented such that a first direction is perpendicular to the semiconductor substrate, and wherein the semiconductor substrate includes an integrated magnetic concentrator (IMC) and at least two horizontal Hall elements arranged at the periphery of the IMC.

[0056] In an embodiment (e.g., as shown in FIG. 4(a)), the magnetic field sensor includes a semiconductor substrate that is substantially located inside the air gap, and the semiconductor substrate is oriented such that the semiconductor substrate is perpendicular to the axis, and wherein the semiconductor substrate includes horizontal Hall elements and vertical Hall elements.

[0057] In an embodiment (e.g., as shown in FIG. 4(b)), the magnetic field sensor includes a semiconductor substrate that is substantially located inside the air gap, and the semiconductor substrate is oriented such that the semiconductor substrate is parallel to the axis and parallel to the first direction, and wherein the semiconductor substrate includes a first vertical Hall element sensitive in the first direction and a second vertical Hall element sensitive in the axial direction.

[0058] In an embodiment (e.g., as shown in FIG. 3(c)), the magnetic field sensor includes a semiconductor substrate that is substantially located inside the air gap, and the semiconductor substrate is oriented such that the semiconductor substrate is perpendicular to the radial direction, and wherein the semiconductor substrate includes horizontal Hall elements and vertical Hall elements.

[0059] In other words, the sensor device may include, for example, an integrated magnetic concentrator (IMC) and two horizontal Hall elements arranged peripherally to the IMC for determining a magnetic field component oriented perpendicular to the semiconductor substrate (e.g., by adding the signals from the two Hall elements) and for determining a magnetic field component parallel to the semiconductor substrate (e.g., by subtracting the signals from the two Hall elements), but the present invention is not limited thereto, and a sensor device having horizontal Hall elements and vertical Hall elements may also be used.

[0060] An advantage of using a magnetic sensor device having only a small number of sensing elements (e.g., only two sensing elements) is that this allows a highly compact design of the magnetic field sensor arrangement according to the present invention.

[0061] Furthermore, in some embodiments, an internal flux concentrator associated with the sensor (also referred to as an IMC) advantageously amplifies a second interfering magnetic flux to be sensed in a second sensing direction (e.g., passively amplifying the magnetic component parallel to the semiconductor plane), which enters the air gap without receiving the amplification of the first flux concentrator and the second flux concentrator (contrary to the signal magnetic flux and the first interfering magnetic flux, which are guided by the first flux concentrator and the second flux concentrator in the first sensing direction).

[0062] The magnetic sensor device may include, for example, two sensing elements for measuring a magnetic field component in a first direction and two other sensing elements for measuring a magnetic field component in a second direction. In a particular embodiment, the sensor device includes four horizontal Hall elements (e.g., a first, second, third, and fourth horizontal Hall element), arranged peripherally to a circular IMC, spaced 90°. The signals from the first and third elements spaced 180° may be added to measure the first magnetic field component. The signals from the second and fourth elements spaced 180° may be subtracted to measure the second magnetic field component. An advantage of using four sensors (instead of just two) is that they allow independent tuning or matching of the two pairs of horizontal Hall elements to improve accuracy.

[0063] Preferably, the magnetic field sensor including one sensing element or a plurality of sensing elements may be arranged within a single chip package (e.g., a plastic molded package), although this is not absolutely required.

[0064] According to a third aspect, the present invention provides a magnetic torque sensor arrangement for stray field immune determination of the torque applied to a torque rod, comprising: an angle sensor arrangement according to the second aspect; the torque rod having a first axial end (directly or indirectly) connected to a first ring and a second axial end (directly or indirectly) connected to a second ring such that when a torque is applied to the torque rod, the torque rod elastically deforms, thereby causing an angular displacement of the first ring and the second ring as a function of the applied torque; and wherein the magnetic field sensor is further configured to convert the signal magnetic flux or the angular displacement into a torque value.

[0065] This conversion can be achieved in a manner known per se, for example using a mathematical expression or a look-up table with optional interpolation.

[0066] Note that with respect to the effects and advantages of the features of the magnetic torque sensor arrangement disclosed herein, reference is generally made to the corresponding similar features and their effects and advantages of the magnetic field sensor arrangement and / or the angle sensor arrangement disclosed herein. Thus, unless otherwise explicitly stated, the features of the magnetic field sensor arrangement and / or the angle sensor arrangement disclosed herein should also be considered applicable to the features defined for the magnetic torque sensor arrangement according to the present invention. Similarly, unless otherwise explicitly stated, the features of the magnetic torque sensor arrangement disclosed herein should also be considered applicable to the features defined for the magnetic field sensor arrangement or the angle sensor arrangement according to the present invention. Therefore, for the purpose of brevity of this specification and to enhance the understandability of the principles of the present invention, the repetition of the explanations of these similar features, their effects and advantages is largely omitted hereinafter.

[0067] The present invention also provides a method for stray field immune determination of the signal magnetic flux generated by a signal magnetic field source in a manner highly immune to magnetic interference fields (e.g., uniform interference fields), the method comprising the steps of: a) providing a magnetic structure including a magnetic source and two magnetic aggregators configured to guide the magnetic flux generated by the source and form an air gap radially oriented with respect to the magnetic structure; b) measuring, inside the air gap, a first magnetic field component signal oriented radially, the first magnetic field component signal indicating a combination of the signal generated by the magnetic source and a first part of the interference field oriented axially with respect to the magnetic structure; c) measuring, inside the air gap, a second magnetic field component signal oriented axially of the magnetic structure, the second magnetic field component signal indicating a second part of the interference field oriented axially with respect to the magnetic structure; d) reducing or eliminating the first interference part by scaling the second signal with a predefined constant and subtracting the scaled signal from the first signal; e) optionally converting the corrected first signal into an angular distance value and / or a torque value, for example, using a mathematical expression or a look-up table.

[0068] A method comprising steps a) to e) is a method for measuring an angular distance and / or a method for measuring a torque value in a manner highly immune to magnetic interference fields.

[0069] The invention also provides a method for stray-field immune determination of a signal magnetic flux generated by a signal magnetic field source, using a magnetic arrangement according to the first aspect, in a manner highly immune to magnetic interference fields (in particular, uniform interference fields), the method comprising the following steps: a) receiving, by a first flux concentrator and a second flux concentrator, a signal magnetic flux and a first portion of the interference field, and guiding the signal magnetic flux and the first portion of the interference field in the first flux concentrator and the second flux concentrator into and through an air gap; b) measuring a first magnetic signal oriented in a first direction, the first magnetic signal indicating the combination of the signal magnetic flux and the first portion of the interference magnetic flux; c) measuring a second magnetic signal oriented in a second direction perpendicular to the first direction, the second magnetic signal indicating the second portion of the interference magnetic flux; d) determining the signal magnetic flux based on the first magnetic signal and the second magnetic signal.

[0070] In an embodiment, step d) comprises: scaling the second magnetic signal with a predefined constant and subtracting the signal from the first magnetic signal, thereby reducing or substantially eliminating the influence of the first interference magnetic flux.

[0071] The present invention also provides a method for stray field immune determination of a signal magnetic flux generated by a signal magnetic field source in a manner highly immune to a uniform interference field, the method comprising the following steps: a) receiving, by a first magnetic flux concentrator and a second magnetic flux concentrator, a signal magnetic flux and a first portion of the interference field, and guiding the signal magnetic flux and the first portion of the interference field in the first magnetic flux concentrator and the second magnetic flux concentrator substantially along the gap direction into and through an air gap formed between an outer face of the first magnetic flux concentrator and an outer face of the second magnetic flux concentrator, wherein the two outer faces are the respective outer faces of the first magnetic flux concentrator and the second magnetic flux concentrator, having a minimum distance therebetween, and the gap direction of the air gap is defined by a line of shortest length therebetween; b) determining, by means of a magnetic field sensor arranged in the air gap and configured to be sensitive to a magnetic field at least in a first sensing direction and a second sensing direction, a first portion of the signal magnetic flux and the interference magnetic flux through its first sensing direction, wherein the first sensing direction and the second sensing direction are substantially perpendicular to each other; c) determining, by means of the magnetic field sensor, a second portion of the interference magnetic flux through its second sensing direction, the second portion passing through the air gap without being received and guided in the first magnetic flux concentrator and the second magnetic flux concentrator; d) reducing or substantially eliminating the amount of the first interference magnetic flux included in the superposition of the signal magnetic flux and the first interference magnetic flux by scaling the amount of the second interference magnetic flux sensed in the second sensing direction and by subtracting the scaled signal from the superposition of the signal magnetic flux and the first interference magnetic flux, the first interference magnetic flux being substantially sensed in the first sensing direction.

[0072] The scaling can be performed in the analog domain or the digital domain. (Generally referred to as "amplification" in the analog domain and "multiplication" in the digital domain). The scaling can be performed using a predefined scaling factor.

[0073] According to a fourth aspect, the present invention provides a method for determining a signal magnetic flux generated by a signal magnetic field source and optionally modulated by a magnetic structure in a manner substantially immune to a magnetic interference field, comprising the following steps: a) providing a magnetic field sensor arrangement according to the first aspect; b) measuring, by means of the magnetic field sensor, a first signal of a magnetic field component oriented in a first direction; c) measuring, by means of the magnetic field sensor, a second signal of a magnetic field component oriented in a second direction perpendicular to the first direction; d) reducing or substantially eliminating the influence of the magnetic interference field based on the measured first magnetic field component and the measured second magnetic field component if the magnetic interference field is present.

[0074] Again, note that with respect to the effects and advantages of the features related to the methods disclosed herein, reference is generally made to the corresponding similar features and their effects and advantages of the magnetic field sensor arrangements and / or angular sensor arrangements and / or magnetic torque sensor arrangements disclosed herein. Thus, unless otherwise explicitly stated, the features of the magnetic field sensor arrangements and / or the features of the angular sensor arrangements and / or the features of the magnetic torque sensor arrangements disclosed herein should also be regarded as features applicable to the definition of the method for determining the signal magnetic flux according to the present invention. Similarly, unless otherwise explicitly stated, the features of the methods disclosed herein should also be regarded as features applicable respectively to the definitions of the magnetic field sensor arrangements and magnetic torque sensor arrangements according to the present invention. Therefore, for the purpose of the brevity of this specification and to enhance the understandability of the principles of the present invention, the repetition of the explanations of these similar features, their effects and advantages is largely omitted hereinafter.

[0075] In an embodiment, step d) includes: scaling the second signal with a predefined constant and subtracting the scaled signal from the first signal.

[0076] In an embodiment, step d) is performed by a processor unit and a memory unit integrated in the magnetic field sensor.

[0077] In an embodiment, step a) includes: a) providing an angular sensor arrangement according to the second aspect; and wherein the method further includes the following step: e) converting the corrected first signal into an angular distance value.

[0078] The method is actually a method for determining an angle in a manner highly insensitive to magnetic interference fields.

[0079] Step e) may include: using a mathematical expression or a look-up table.

[0080] In an embodiment, step a) includes: a) providing a torque sensor arrangement according to the third aspect; and the method further includes the following step: e) converting the corrected first signal into a torque value.

[0081] The method is actually a method for determining torque in a manner highly insensitive to magnetic interference fields.

[0082] The specific and preferred aspects of the present invention are set forth in the appended independent and dependent claims. The features from the dependent claims may be combined with the features of the independent claims and the features of other dependent claims where appropriate, not only as explicitly set forth in these claims.

[0083] These and other aspects of the present invention will be apparent from the (multiple) embodiments described hereinafter, and these and other aspects of the present invention are elucidated with reference to these embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Figures 1(a) and 1(b) respectively show a side view and a front view of an embodiment of a magnetic field sensor arrangement known in the art.

[0085] Figure 2 (a) and Figure 2 (b) respectively show a side view and a front view of exemplary embodiments of a magnetic field sensor arrangement and an angle sensor arrangement according to the present invention.

[0086] Figures 3(a), 3(b) and 3(c) show enlarged views of an embodiment of the present invention, showing Figure 2 a part of the magnetic field sensor arrangement shown in (a). The sensor device in Figure 3(a) is horizontally oriented and includes two horizontal Hall elements and an integrated magnetic concentrator (IMC). The sensor device in Figure 3(b) is vertically oriented and includes two horizontal Hall elements and an IMC. The sensor device in Figure 3(c) is vertically oriented and includes a horizontal Hall element and a vertical Hall element.

[0087] Figures 4(a) and 4(b) show views Figures 3(a) to 3(c) similar to, but showing views of other exemplary embodiments of a magnetic field sensor arrangement according to the present invention. The sensor device in Figure 4(a) is horizontally oriented and includes a horizontal Hall element and a vertical Hall element. The sensor device in Figure 4(b) is vertically oriented and includes two vertical Hall elements.

[0088] Figure 5 shows a side view of another exemplary embodiment of a magnetic field sensor arrangement according to the present invention, which can be regarded as Figure 2 a variant of the magnetic field sensor arrangement, in which one of the magnetic yokes has a protruding part for defining an air gap. The sensor device is represented by a black rectangle. Any sensor device in Figures 3(a) to 4(b) the sensor devices can be used.

[0089] Figure 6 (a) and Figure 6 (b) respectively show Figure 2 the side view and the front view of the magnetic field sensor arrangement shown, which depicts the process of the first part of the magnetic flux lines generated by an external interfering magnetic field source (located at the Figure 6 top). This first part passes through the air gap along the gap direction (radial with respect to the magnetic structure).

[0090] Figure 7 (a) and Figure 7 (b) show the same arrangement as Figure 6 above, but now show the process of the second part of the magnetic flux lines generated by the interfering magnetic field source. This second part passes through the air gap in a direction perpendicular to the gap direction.

[0091] Figure 8 (a) and Figure 8 (b) respectively show Figure 2 a side view and a front view of the magnetic field sensor arrangement shown, which depicts the process of magnetic flux lines generated by another external interfering magnetic field source (located at Figure 8 the left part). These magnetic flux lines do not pass through the air gap (neither radially nor axially).

[0092] Figure 9 (a), Figure 9 (b) and Figure 9 (c) respectively show Figure 2 a perspective view, a side view and a front view of the magnetic field sensor arrangement and the angle sensor arrangement shown.

[0093] Figure 10 (a) and Figure 10 (b) respectively show a side view and a front view of another exemplary embodiment of the magnetic field sensor arrangement according to the present invention.

[0094] Figure 11 (a), Figure 11 (b) and Figure 11 (c) respectively show Figure 10 a perspective view, a side view and a front view of the magnetic field sensor arrangement and the angle sensor arrangement shown.

[0095] Figure 12 A flowchart of a method for determining a signal magnetic flux generated by a signal magnetic field source and optionally modulated by a magnetic structure in a manner highly immune to an interference field according to an embodiment of the present invention is shown.

[0096] These figures are merely illustrative and not restrictive. In the figures, for illustrative purposes, the dimensions of some of the elements may be enlarged and not drawn to scale. Any reference signs in the claims should not be construed as limiting the scope. In the various figures, equivalent elements with respect to their functions always have the same reference signs, and thus these elements are generally described only once. Detailed Description

[0097] The present invention will be described with respect to specific embodiments and with reference to specific figures, but the present invention is not limited thereto and is only defined by the claims. The described figures are merely illustrative and non - restrictive. In the figures, for illustrative purposes, the dimensions of some of the elements may be enlarged and not drawn to scale. The dimensions and relative dimensions do not correspond to an actual true reduction of the present invention.

[0098] Moreover, the terms first, second, etc. in the description and claims are used to distinguish between similar elements and are not necessarily used to describe an order in time, space, ranking, or any other manner. It should be understood that the terms so used are interchangeable where appropriate, and the embodiments of the invention described herein are capable of operating in a different order than that described or illustrated herein.

[0099] In addition, the terms top, bottom, etc. in the description and claims are used for descriptive purposes and are not necessarily used to describe relative position. It should be understood that the terms so used are interchangeable where appropriate, and the embodiments of the invention described herein are capable of operating in an orientation different from that described or illustrated herein.

[0100] It should be noted that the term "comprising" used in the claims should not be construed as being limited to the means listed thereafter; it does not exclude other elements or steps. Thus, the term should be construed as specifying the presence of the stated features, integers, steps, or components as mentioned, but not excluding the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Thus, the scope of the expression "an apparatus comprising apparatus A and apparatus B" should not be limited to an apparatus consisting only of components A and B. It means that the relevant components of the apparatus for the purposes of the present invention are only A and B.

[0101] References to "one embodiment" or "an embodiment" throughout this specification mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" throughout this specification are not necessarily all referring to the same embodiment, but may refer to the same embodiment. Additionally, in one or more embodiments, as will be apparent to those of ordinary skill in the art through the present disclosure, the particular features, structures, or characteristics can be combined in any suitable manner.

[0102] Similarly, it should be appreciated that in the description of the exemplary embodiments of the present invention, for the purposes of streamlining the present disclosure and aiding in the understanding of one or more of the inventive aspects, the various features of the present invention are sometimes grouped together in a single embodiment, drawing, or description thereof. However, such a method of disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. On the contrary, as reflected in the appended claims, the inventive aspects lie in less than all of the features of a single foregoing disclosed embodiment. Thus, the appended claims of the detailed description are hereby expressly incorporated into the detailed description, where each claim itself represents a separate embodiment of the invention.

[0103] In addition, as will be understood by those skilled in the art, although some embodiments described herein include some features included in other embodiments but do not include other features included in other embodiments, the combination of features of different embodiments is intended to be within the scope of the present invention and form different embodiments. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

[0104] In the description provided herein, numerous specific details are set forth. However, it is to be understood that embodiments of the present invention may be implemented without these specific details. In other instances, well-known methods, structures, and techniques are not shown in detail to avoid obscuring an understanding of this description.

[0105] In this document, the terms "magnetic interference field" and "magnetic stray field" are considered synonymous. Unless otherwise explicitly stated, they will be used interchangeably in this document and refer to essentially the same subject matter.

[0106] In this document, the expressions "immune to stray fields" and "highly insensitive to external interference fields" and "highly robust to external interference fields" have the same meaning.

[0107] In this document, the expressions "for determining immune to stray fields" and "for determining in a manner substantially immune to stray fields" have the same meaning.

[0108] In this document the terms "(external) magnetic field concentrator" or "flux guide" or "yoke" are used synonymously.

[0109] In this document, the terms "magnetic field sensor" and "magnetic sensor device" or "sensor device" are used synonymously. The magnetic sensor device comprises a semiconductor substrate having at least two magnetic sensor elements (e.g. Hall elements). The magnetic sensor device may be packaged in a molded package, but this is not absolutely necessary.

[0110] In the present document, the magnetic field sensor arrangement may be associated with a first orthogonal coordinate system X, Y, Z having an axial direction (denoted Z), a radial direction through the air gap (denoted X), and a circumferential direction Y (e.g., Figure 2 a and Figure 2 b).

[0111] In this document, the semiconductor plane of the magnetic field sensor can be associated with a second orthogonal coordinate system U, V, W, wherein the U axis and the V axis are parallel to the semiconductor plane and the W axis is perpendicular to the semiconductor plane.

[0112] The expressions "signal magnetic field" or "signal magnetic flux" as used herein refer respectively to the (desired) signal or magnetic flux originating from a "signal magnetic field source" (e.g., a multipolar ring magnet) that is part of a magnetic arrangement. This signal and magnetic flux are used as measurement signals, for example to non - contactlessly determine the angular displacement between two shaft portions (such as a steering column, etc.).

[0113] In this document, the term "signal magnetic field source" refers to a "magnetic source", e.g., one or more permanent magnets, a part of a magnetic arrangement, such as a radially magnetized multipolar ring magnet.

[0114] In this document, the terms "magnetic field sensor arrangement", "magnetic arrangement", or "magnetic structure" are used as synonyms.

[0115] In this document, unless otherwise explicitly stated, the terms "magnetic field sensor" or "magnetic sensor device" refer to a device including at least two magnetosensitive elements. The sensor device may be included in a package (also referred to as a "chip"), but this is not absolutely necessary. In an embodiment of the present invention, the magnetic sensor includes a semiconductor substrate. The at least two magnetosensitive elements may be integrated in the substrate.

[0116] In this document, the terms "sensor element", "magnetic sensor element", or "sensor" may refer to a component or a set of components or a sub - circuit or structure capable of measuring a magnetic quantity, such as, for example, a magnetoresistive element, an XMR element, a horizontal Hall plate, a vertical Hall plate, a Wheatstone bridge including at least one (but preferably four) magnetoresistive elements, a structure including a disk - shaped magnetic aggregator and two or four horizontal Hall elements arranged near the periphery of the disk, etc.

[0117] Figures 1(a) and 1(b) respectively show a side view and a front view of a torque sensor 100 known in the art, including a magnetic structure 110 and a magnetic field sensor arrangement 120. The sensor arrangement 120 is configured to determine the signal magnetic flux (not specifically indicated) generated by a signal magnetic field source S1 (e.g., a radially magnetized multipolar ring magnet (not explicitly shown)). The sensor arrangement 120 can also be regarded as the "read - out part" of the torque sensor 100.

[0118] However, this torque sensor 100, or especially this sensor arrangement 120, is not sensitive to an external interfering magnetic field or magnetic flux (not shown in Figure 1, but see, for example, Figures 6 to 8)Immunity. Although strictly speaking, such currents do not produce a uniform field (i.e., constant direction and amplitude), in practice, within a relatively small space at a sufficient distance from the conductor (e.g., at a distance of at least 10 cm, or at least 20 cm from the current conductor), the magnetic interference field can be considered "substantially uniform".

[0119] The prior art sensor arrangement 120 includes a first flux concentrator 101 and a second flux concentrator 102 (also referred to as a yoke or a flux director). An air gap 103 is formed between the outer face 104 of the first flux concentrator 101 and the outer face 105 of the second flux concentrator 102. There is a direct line of sight between the first outer face 104 and the second outer face 105. The "gap direction" 106 can be defined by the line of the shortest length (or the line of the shortest distance) between the two outer faces 104, 105 of the first flux concentrator 101 and the second flux concentrator 102. In the arrangement of Fig. 1(a), the "gap direction" is oriented in the Z direction (i.e., along the axis of the magnetic structure 110). Furthermore, a magnetic field sensor 107 (schematically indicated by the black rectangle) is arranged in the air gap 103. The magnetic field sensor 107 of the sensor arrangement 120 shown in Fig. 1 is sensitive to the magnetic field component Bz in the Z direction (i.e., along the axis of the structure 110).

[0120] The torque sensor 100 of Fig. 1 further includes a magnetic structure or magnetic arrangement 110, which includes a signal magnetic field source S1 that generates a signal magnetic flux (not shown), such as a radially magnetized multi-pole ring magnet. The magnetic structure 110 is configured and arranged such that the signal magnetic flux is modulated as a function of the relative angular displacement between a first magnetic ring 111 and a second magnetic ring 112 around the signal magnetic field source S1. As depicted in Fig. 1, the two magnetic rings 111, 112 have respective tooth-shaped or fin-shaped protrusions 113, 114 (also referred to as "teeth" or "claws" or "pads") arranged along the periphery of each magnetic ring 111, 112, and the free ends thereof point towards each other in an opposite manner. The protrusions 113, 114 of the first ring 111 and the second ring 112 extend substantially in the direction of the common rotation axis 115 of the two rings 111, 112. The magnetic field source S1 is arranged on the axis 115, between the centers of the first ring 111 and the second ring 112.

[0121] Accordingly, the components 111, 112, 113, 114, S1 shown without shading are considered as part of the “magnetic structure” 110, while the shaded components 101, 102 and the sensor 107 are considered as part of the “(magnetic field) sensor arrangement” 120. The combination of the magnetic structure 110 and the sensor arrangement 120 as shown in FIG. 1 is known to be used as a magnetic torque sensor arrangement 100 for determining the torque applied to a torque rod (not shown in FIG. 1) that elastically connects (e.g., via a torsion bar) the end of a first shaft (also referred to as the input shaft) to the end of a second shaft (also referred to as the output shaft). Further details of various embodiments of such a combination are disclosed, for example, in the above-mentioned documents DE 102 22 118 A1 or EP3505894.

[0122] In addition, the signal magnetic flux generated by the signal magnetic field source S1 of the magnetic torque sensor arrangement shown in FIG. 1 is received by the first magnetic flux concentrator 101 and the second magnetic flux concentrator 102 and is guided substantially in the gap direction 106 (= Z direction) within the first magnetic flux concentrator 101 and the second magnetic flux concentrator 102 to the air gap 103, where the signal magnetic flux is sensed by the magnetic field sensor 107.

[0123] Now, if there is an interfering magnetic flux substantially generated in the Z direction by an interfering magnetic field source S2, this magnetic flux will also be captured / received by the first magnetic flux concentrator 101 and the second magnetic flux concentrator 102 and guided within the first magnetic flux concentrator 101 and the second magnetic flux concentrator 102, so that it superimposes and adds to the signal magnetic field within the two magnetic flux concentrators 101, 102. Therefore, since the magnetic field sensor 107 cannot distinguish between the signal magnetic flux and the interfering magnetic flux guided to the air gap 103, the torque sensor 100 including the sensor arrangement 120 shown in FIG. 1 is not immune (or robust) to the (external) interfering magnetic flux generated by the (external) interfering magnetic field source S2.

[0124] Figure 2 (a) and Figure 2 (b) respectively show a side view and a front view of an exemplary embodiment of a torque sensor arrangement 200 including the magnetic structure 110 of FIG. 1 but including a modified sensor arrangement 220. Generally, the torque sensor 200, in particular the sensor arrangement 220, is capable of determining the signal magnetic flux generated by the signal magnetic field source S1 (e.g., a radially magnetized multi-pole ring magnet) and optionally modulated by the magnetic structure 110 in a stray field immune manner.

[0125] In Figure 2In this context, the magnetic field sensor arrangement 220 is also shown in combination with the magnetic structure 110 (or magnetic arrangement 110) as depicted in FIG. 1. Thus, the combination of the magnetic field sensor arrangement 220 and the magnetic arrangement 110 can form a magnetic torque sensor arrangement 200 for immune determination of the torque applied to a torque rod (not shown) with respect to the stray field.

[0126] As Figure 2 shown, the magnetic field sensor arrangement 220 includes a first flux concentrator 201 and a second flux concentrator 202 (also referred to as a flux director or a magnetic yoke). The flux concentrators 201, 202 are configured and arranged such that an air gap 203 is formed between the outer face 204 of the first flux concentrator 201 and the outer face 205 of the second flux concentrator 202. The two outer faces 204, 205 are the respective outer faces of the first flux concentrator 201 and the second flux concentrator 202, with a minimum distance therebetween, and the "gap direction" 206 of the air gap 203 is defined by a line of the shortest length (or shortest distance) between the first outer face 204 and the second outer face 205. The magnetic field sensor (or sensor device) 207 indicated by the black rectangle is configured to be sensitive to the magnetic field in at least a first sensing direction X and a second sensing direction Z, where the first sensing direction X and the second sensing direction Z are substantially perpendicular to each other.

[0127] More specifically, the X direction is substantially radially oriented with respect to the magnetic structure 110 (thus perpendicular to the axis 115 and preferably intersecting the axis 115), and the Z direction is substantially parallel to the axis 115 (thus parallel to the torque rod if there is a torque rod). In other words, the X direction is substantially located in the virtual plane X - Y perpendicular to the axis 115.

[0128] Furthermore, the first flux concentrator 201 and the second flux concentrator 202 are further configured and arranged such that the signal magnetic flux generated by the signal magnetic field source S1 and a first portion 228 of the interference magnetic flux generated by an interference magnetic field source S2 different from the signal magnetic field source S1 (see Figure 6 (a)) will be received by the first flux concentrator 201 and the second flux concentrator 202 and substantially in the air gap direction 206 within the first flux concentrator 201 and the second flux concentrator 202, thereby being guided into and through the air gap 203 in the radial direction X. A second portion 229 of the interference magnetic flux generated by the interference magnetic field source S2 (see Figure 6 (a)) will pass through the air gap 203 without being received by the first flux concentrator 201 and the second flux concentrator 202 and being guided into the air gap 203 within the first flux concentrator 201 and the second flux concentrator 202. This is an important aspect of the present invention and will be further explained in more detail.

[0129] As described above, if the torque sensor 200 is far enough from the external interference source S2 (e.g., at least 10 cm, or at least 20 cm, or at least 30 cm away), the external interference field can be considered to be substantially uniform, especially "inside the air gap". The magnetic field sensor 207 is arranged in the air gap 203 such that it can sense the combined signal magnetic flux and a first part of the interference magnetic flux passing through the air gap in the first direction X and a second part of the interference magnetic flux passing through the air gap in the second direction Z. Depending on the orientation of the sensor device, the X direction and the Z direction can be parallel or orthogonal to the semiconductor substrate, as will be further described (in Figures 3(a) to 4(b) ).

[0130] The "air gap space" can be defined as the 3D space between the above-mentioned first external face 204 and the second external face 205, more specifically, the 3D space between the corresponding points of these faces, for which the distance is substantially equal to the "minimum distance" within a small tolerance margin (e.g., + / - 10% or + / - 5%). In Figure 2 's example, this 3D space has a length 206 (in the X direction) equal to the "gap length", and has a cross-sectional area (in the Y-Z plane) defined by the shape of the first external face 204 and the second external face 205 (e.g., by the overlap of the projections of these external faces in the gap direction on the Y-Z plane). In Figure 2 's example, this overlap is substantially rectangular, having a width 209 (see Figure 2 (b)) and a height 210 (see Figure 2 (a)). Thus, in Figure 2 's example, the "air gap space" or "the space of the air gap" is substantially beam-shaped, but can also be substantially cubic.

[0131] Preferably, the sensor device 207 is substantially arranged inside the air gap 203, in the sense that all the magnetosensitive elements (e.g., Hall elements and / or IMCs) of the magnetic sensor 207 are located inside this air gap space.

[0132] Figures 3(a) and 3(b) show Figure 2 an enlarged view of a part of the magnetic field sensor arrangement 220 shown, especially the part near the air gap 203, of two embodiments.

[0133] In the embodiment of Figure 3(a), the semiconductor substrate of the magnetic sensor device 207a is substantially oriented parallel to the X-Y plane, i.e., parallel to the gap direction 206, and perpendicular to the axial Z direction.

[0134] Assume that a second coordinate system with axes U, V, and W is associated with the sensor device 207a such that the semiconductor substrate is parallel to the UV plane and orthogonal to the W axis. Then, the U axis of the sensor device corresponds to the X axis of the magnetic structure, the V axis of the sensor device corresponds to the Y axis of the magnetic structure, and the W axis of the device corresponds to the Z axis of the magnetic structure. Therefore, stating that the sensor device needs to be sensitive in the X direction and the Z direction with respect to the magnetic structure is equivalent to stating that the sensor device 207a needs to be sensitive in the U direction and the W direction.

[0135] Figure 3a The depicted sensor device 207a includes an integrated magnetic concentrator (IMC) 211 and two horizontal Hall elements 212a, 212b arranged near the periphery of the IMC. Such sensor structures are known in the art and are capable of measuring the (so-called "out-of-plane") magnetic field component Bw oriented perpendicular to the semiconductor substrate and the (so-called "in-plane") magnetic field component Bu oriented parallel to the semiconductor substrate. Readers unfamiliar with such sensor structures can find more information, for example, in the patent publication US2018372475(A1) (see FIGS. 4(a) to 4(c)) or the patent application EP3505894A1 filed by the same applicant on December 21, 2018, especially Figure 6 and Figure 7 (a, b, c), and these two documents are hereby incorporated by reference in their entirety. However, note that other suitable sensor devices capable of measuring two orthogonal magnetic field components can also be used. The sensor device 207 needs to be oriented such that the sensor device can measure two orthogonal magnetic field components, one oriented in the gap direction 206 (corresponding to the X direction of the magnetic structure) and the other perpendicular to the gap direction (corresponding to the Z direction of the magnetic structure).

[0136] Referring to FIG. 3(a) of the present invention, the sensor device 207a is oriented such that its semiconductor substrate is perpendicular to the Z axis. The sensor device 207a includes an integrated magnetic concentrator (IMC) 211 (e.g., a disk-shaped IMC) and two horizontal Hall elements 212a, 212b located near the periphery of the IMC. The sensor device 207a is capable of measuring the out-of-plane magnetic field component Bw (oriented in the Z direction of the magnetic structure) and the in-plane magnetic field component Bu (oriented in the X direction of the magnetic structure).

[0137] The Bw signal can be determined, for example, by adding the signals obtained from the two Hall elements 212a, 212b. The Bu signal can be determined, for example, by subtracting the signals from the two Hall elements. In this orientation of the sensor device 207a, the Bu signal indicates the signal magnetic flux and the first part 228 of the interference magnetic flux (see Figure 6a) In the case of the superposition (if present), the Bw signal only indicates the second part 229 of the interfering magnetic flux. In this orientation of the sensor device 207a, the Bu signal is passively amplified due to the presence of the integrated magnetic concentrator 211. However, this orientation is not ideal because (i) the width of the substrate is typically greater than its thickness, so the gap distance needs to be relatively large to accommodate the sensor device 207a, and (ii) the second part 229 of the interfering magnetic flux is usually very weak and not amplified by the magnetic flux concentrator.

[0138] Referring to FIG. 3(b), the sensor device 207b can be the same sensor device as the sensor device 207a in FIG. 3(a), but rotated 90° about the Y axis. The sensor device 207a is capable of measuring the out-of-plane magnetic field component Bw oriented in the X direction of the magnetic structure and the in-plane magnetic field component Bu oriented in the Z direction of the magnetic structure. In this orientation of the sensor device 207b, the Bw signal indicates the superposition of the signal magnetic flux and the first interfering part 228 (not amplified by the IMC); and the Bu signal indicates the second interfering part 229, and the Bu signal is passively amplified by the IMC.

[0139] The advantage of this embodiment is that the gap distance 206 in FIG. 3(b) can be smaller than the gap distance 206 in FIG. 3(a). This is true not only for the packaged sensor device but also for the unpackaged sensor device because the substrate thickness is usually much smaller than the substrate width. In addition, the semiconductor substrate thickness can be further reduced by a process called "wafer thinning". In this case, a substrate with a thickness less than 500 μm or less than 400 μm or less than 300 μm can be used. Using a smaller gap distance 206 has a positive impact on the magnetic flux density, and thus on the signal-to-noise ratio, and thus on the accuracy of the signal. Another advantage is that the (weak) second interfering part 229 is passively amplified by the IMC.

[0140] Or in other words, a particular advantage of this "vertical arrangement" of the magnetic field sensor 207b relative to the "horizontal arrangement" shown in FIG. 3(a) is that the magnetic gain provided by the internal magnetic concentrator 211 can be used to amplify the (interfering) magnetic flux Bz entering the air gap 203 in the Z direction, as opposed to the magnetic flux Bx entering the air gap 203 in the X direction, which has been (externally) amplified by the two magnetic concentrators (or magnetic yokes) 201, 202.

[0141] However, the present invention is not limited to the examples shown in FIGS. 3(a) and 3(b), and other sensor devices, such as sensor devices including magnetoresistive elements, can also be used.

[0142] FIG. 3(c) shows a variant of the sensor arrangement of FIG. 3(b). The sensor device 207c of FIG. 3(c) is also oriented "vertically" (i.e., its semiconductor substrate is parallel to the Y-Z plane), but includes a horizontal Hall element 212c and a vertical Hall element 212d. The horizontal Hall element 212c is configured to measure a first magnetic field component in the W direction relative to the substrate corresponding to the radial direction of the magnetic structure, and a second magnetic field component in the U direction corresponding to the axial direction of the magnetic structure.

[0143] This embodiment has the advantages of not requiring an IMC and having a small gap distance, but does not provide passive amplification of the second interference field portion 229 (not shown, but passing axially through the air gap in the Z direction).

[0144] FIGS. 4(a) and 4(b) show views similar to FIG. 3, but show views of other exemplary embodiments of a magnetic field sensor arrangement (not shown in its entirety) according to the present invention. In these embodiments, the magnetic field sensors 213a, 213b include at least one sensing element 214, such as, for example, a magnetoresistive element, an XMR element, a vertical Hall plate, a Wheatstone bridge including at least one magnetoresistive element, etc., and the magnetic field sensors 213, 213b are sensitive to each of at least two sensing directions X, Z (relative to the magnetic arrangement) or U, V (relative to the semiconductor substrate). The sensor device 213 of FIG. 4 does not include an integrated magnetic field concentrator (IMC).

[0145] More specifically, in the embodiment of FIG. 4(a), the semiconductor substrate is oriented "horizontally" (i.e., the substrate is parallel to the X-Y plane and the substrate thickness is in the Z direction), and the sensor element 214a is a vertical Hall element configured to measure Bx, and the sensor element 214b is a horizontal Hall element configured to measure Bz.

[0146] In the embodiment of FIG. 4(b), the semiconductor substrate is oriented "vertically" (the substrate is parallel to the X-Z plane and the substrate thickness is in the Y direction), the sensor element 216a is a vertical Hall element configured to measure the signal Bx (a combination of the desired signal and the first interference portion 228), and the sensor element 216b is a vertical Hall element configured to measure the signal Bz (including only the second interference portion 229).

[0147] In some embodiments of the present invention, where at least two sensor elements are used in a magnetic field sensor, the sensor elements may have different sensitivities to the magnetic field to be detected. For example, different sensitivities can be achieved by using the above different sensor technologies and / or different sensor configurations (e.g., with / without an internal flux concentrator), by using different biasing means (e.g., voltage or current), by using different electronic gains, etc.

[0148] Note that the magnetic field sensors 207, 213 shown in FIGS. 3 and 4, respectively, can each be provided as a single semiconductor substrate, optionally encapsulated in a single chip package. Although not shown, as described herein, the substrate and / or the chip package can also include a processor unit (e.g., a microprocessor or a microcontroller) and a memory unit (e.g., volatile and / or non-volatile memory such as RAM, ROM, flash memory, etc.). The processor, memory, etc. do not need to be located inside the air gap, but it is important that the magnetosensitive element is located inside the air gap.

[0149] In a preferred embodiment of the present invention, the sensor device is configured to determine the magnetic flux generated by the first magnetic field source S1 and modulated by the magnetic structure 110 by performing the following steps:

[0150] a) Measuring a first magnetic field component Bx oriented along the gap direction (radial direction of the magnetic structure 110);

[0151] b) Measuring a second magnetic field component Bz oriented in a direction perpendicular to the gap direction (axial direction of the magnetic structure 110);

[0152] c) Multiplying the second signal by a predefined constant K to obtain an estimate of the first interference portion 228. The value of K can be hard-coded or stored in non-volatile memory;

[0153] d) Subtracting the first signal and the said estimate of the first interference portion, thereby reducing or substantially eliminating the influence of the external interference field that is considered to be substantially uniform at least inside the air gap.

[0154] Depending on the application (e.g., angle sensor or torque sensor application), the method can include a further step e) of demodulating the subtraction result, for example, using a look-up table, optionally with linear interpolation.

[0155] FIG. 5(a) shows a side view of another exemplary embodiment of an angle sensor or torque sensor 500 including a magnetic field sensor arrangement 240 according to the present invention. Compared with Figure 2 the magnetic field sensor arrangement 220 shown, the magnetic field sensor arrangement 240 of FIG. 5 includes a first magnetic flux concentrator 221 having a slightly different configuration near the air gap 203, as will be described below.

[0156] In Figure 2 this case, the external face 204 is the region on the side of the vertically oriented leg portion 224 of the first magnetic flux concentrator 221, where the magnetic flux lines (not shown) pass through the air gap, which actually means at the position where the distance to the external surface 205 of the second magnetic flux concentrator 202 is minimized. In this case, the external face region 204 is not clearly defined.

[0157] In Fig. 5(a), the outer face 204 of the first flux concentrator 221 is also provided on a portion 223 of the first flux concentrator 221, which is located at the position where the field lines will leave the first flux concentrator 201. This actually means at the position where the distance to the outer surface 205 of the second flux concentrator 202 is minimized. However, in this case, the boundary of the outer face 204 is precisely defined by means of a protrusion 226 or a bend 226 etc. that extends radially outward relative to the first flux concentrator 221.

[0158] As can be seen, the first magnetic concentrator 221 in Fig. 5(a) has a Z shape (in a cross-sectional plane parallel to the X-Z plane). More specifically, the first flux concentrator 221 (or yoke) has protrusions or bent portions that point towards the air gap 203. Thus, the outer face 204 is clearly defined and is located at the end of such protrusions or bent portions.

[0159] Fig. 5(b) shows another angle sensor or torque sensor 550 that is a variant of the angle sensor or torque sensor 500 in Fig. 5(a). The magnetic structure 110 is Figure 2 the same as the magnetic structure in Fig. 5(a), but the sensor arrangement 250 is slightly different. In this case, the first magnetic yoke 251 arranged adjacent to the first ring 111 extends further radially outward than the second magnetic yoke 252. However, importantly, also in this case, the gap direction 206 is oriented radially in the X direction with respect to the magnetic structure 110 between the first face 204 on the first flux concentrator 251 and the second face 205 on the second flux concentrator 252.

[0160] Those skilled in the art who benefit from this disclosure will understand that Figs. 5(a) and 5(b) are two examples where the air gap 203 is substantially located at the same axial position as the lower ring 112. However, of course, the present invention is not limited thereto, and the air gap 203 can also be located at a different axial position, for example, at a position substantially intermediate between the first ring 111 and the second ring 112. This can be achieved by reducing the length of the vertical (axial) legs 224 of the first concentrators 201, 221, 251 and by increasing the vertical (axial) legs of the second concentrators 202, 252 such that the gap direction 206 of the air gap 203 therebetween is oriented radially in the X direction.

[0161] Although not explicitly shown, Figure 2 the same is of course true. Similarly, here, the position of the air gap 203 can be axially shifted by making the vertical legs 224 (extending in the Z direction) shorter and by making the vertical legs of 202 (extending in the Z direction) longer.

[0162] In addition, although not explicitly shown in Figs. 5(a) and 5(b), the sensor device 207 can be similar to Figures 3(a) to 4(b)arranged in the air gap in any of the manners shown.

[0163] Figure 6 (a) and Figure 6 (b) respectively show Figure 2 the side view and the front view of the angle sensor arrangement or the magnetic torque sensor arrangement 200 shown, and the magnetic field sensor arrangement 220. In addition, the process of the magnetic flux lines 227a caused by the first part 228 of the magnetic field generated by the external interference magnetic field source S2 and oriented in the Z direction at the position of the torque sensor arrangement is depicted.

[0164] As shown, the first part 228 of the external magnetic interference field generated by the interference magnetic field source S2 is received by the first magnetic flux concentrator 201 and the second magnetic flux concentrator 202 and is guided into and through the air gap 203 substantially along the air gap direction 206 within the first magnetic flux concentrator 201 and the second magnetic flux concentrator 202, wherein this first part is sensed by the magnetic field sensor 207 through one or more sensor elements sensitive in the X direction. In fact, the signal sensed in the X direction is not only the first interference part 228, but also the superposition of this (undesired) first interference part 228 and the (desired) signal magnetic flux, which is generated by the signal magnetic field source S1 (such as a radially oriented multi-pole ring magnet located at a substantially intermediate position between the first ring 111 and the second ring 112) and optionally modulated by the magnetic structure 110. The sensor device 207 cannot distinguish the (desired) signal magnetic flux and the (undesired) interference magnetic flux based only on the signal measured in the X direction.

[0165] Figure 7 (a) and Figure 7 (b) respectively show Figure 2 the side view and the front view of the magnetic torque sensor arrangement 200 and the magnetic field sensor arrangement 220 shown. In addition, the process of the magnetic flux lines 227b caused by the second part 229 of the magnetic field generated by the external interference magnetic field source S2 and oriented in the Z direction at the position of the torque sensor arrangement is depicted.

[0166] The second part 229 is not received by the first flux concentrator 201 and the second flux concentrator 202 and is guided into the air gap 203 within the first flux concentrator 201 and the second flux concentrator 202. Instead, the second interfering magnetic flux 229 passes through the air gap 203 in the Z direction (i.e., the axial direction of the magnetic structure) perpendicular to the X direction. The second interfering magnetic flux 229 is sensed by the magnetic field sensor 207 via one or more sensor elements sensitive in the Z direction. In this way, the amount of the external interfering magnetic flux 229 present in the vicinity of the magnetic structure 200 and the field sensor arrangement 220 can be determined (e.g., measured) independently of the external interfering magnetic flux 228 flowing within the first flux concentrator 201 and the second flux concentrator 202. Since the first part 228 and the second part 229 are from the same source S2, the amplitudes of the first part 228 and the second part 229 are correlated. This correlation can be approximated by a predefined factor. The predefined factor is independent of the amplitude of the external interfering field, but is mainly related to the shape, size, and material of the magnetic arrangement 200 (including the magnetic structure 110 and the magnetic sensor arrangement 220), and can be determined by design, by simulation, by calibration, or in any other suitable way. The predefined factor can be hard-coded in a program executed by a microcontroller or can be stored in the non-volatile memory of the sensor device.

[0167] Therefore, the total magnetic flux sensed by the magnetic sensor 207 in the X direction (which is the superposition of the desired signal and the first interfering part) can be corrected by simple arithmetic operations, more specifically, by scaling the magnetic signal Bz sensed by the magnetic sensor 207 in the Z direction with the predefined factor and by subtracting the scaled signal from the magnetic signal Bx sensed by the magnetic sensor 207 in the X direction. Note that the actually used scaling factor can also take into account the sensitivity difference between the X direction and the Z direction of the sensor device (e.g., due to IMC amplification), and / or the amplification factor caused by the first flux concentrator 201 and the second flux concentrator 202. Therefore, the interfering field can be reduced or substantially eliminated in a surprisingly simple way.

[0168] In addition, it should be noted that the interfering magnetic fluxes 228, 229 generated by the external interfering magnetic field source S2 can originate from a homogeneous or uniform interfering magnetic field or from a non-uniform field source (e.g., a current-carrying wire) located at a sufficient distance (e.g., at least 10 cm or at least 20 cm) from the magnetic sensor arrangement.

[0169] In Figure 6 and Figure 7 the influence from an external interfering field oriented in the Z direction is described. As explained, this can be greatly reduced or completely eliminated.

[0170] Although not explicitly shown, it can be understood that an external interference field oriented in the Y direction has no effect on the measurement because a first portion of the interference field received in the Y direction by the first flux concentrator and the second flux concentrator will also leave the first flux concentrator and the second flux concentrator in the Y direction without passing through the air gap, and because the sensor device itself is insensitive to the magnetic field passing through the air gap in the Y direction.

[0171] Figure 8 (a) and Figure 8 (b) respectively show Figure 2 side and front views of the magnetic torque sensor arrangement 200 and the magnetic field sensor arrangement 220 shown, further depicting the process of the magnetic flux lines 227 generated by an external interfering magnetic field source S3 (located Figure 8 to the left) that generates an interference field oriented in the X direction.

[0172] As is obvious from Figure 8 it, the interfering magnetic flux 230 oriented in the X direction basically does not (or at most to a very small, negligible extent) enter the air gap 203 because most of the magnetic flux lines enter the rings 111, 112 but leave the magnetic structure via the vertical legs of the first flux concentrator 201 and the second flux concentrator 202. Only a small portion of the magnetic flux entering the first ring 111 will pass through the air gap and leave the sensor structure via the second flux concentrator 202, and thus it will basically not contribute to the total magnetic flux sensed by the magnetic field sensor 207 in the X direction.

[0173] Since a uniform interference field oriented in any direction can be decomposed into three orthogonal components, one oriented in the Z direction, one oriented in the X direction, and one oriented in the Y direction, it can be understood from the above that the signal magnetic flux generated by the magnetic source S1 (e.g., a multi-pole ring magnet) can be measured in a manner that is highly robust to external interference fields oriented in any direction because the interfering magnetic flux in the Z direction passes through the air gap but is compensated, the interfering magnetic flux oriented in the Y direction does not pass through the air gap, and the interfering magnetic flux in the X direction does not pass through or does not significantly pass through the air gap, and thus does not affect or does not significantly affect the measurement of the signal generated by the first magnetic source S1.

[0174] Figure 9 (a), Figure 9 (b) and Figure 9 (c) respectively show Figure 2A perspective view, side view, and front view of a magnetic field sensor arrangement 220 adapted for use in combination with a magnetic arrangement 110 as an angle sensor and / or magnetic torque sensor arrangement 200 as disclosed herein. The magnetic arrangement 110 includes a radially magnetized multi-pole ring magnet S1 and may further include a torsion bar (not shown), for example, similar or identical to the torsion bars described in DE10222118A1 or EP3505894A1.

[0175] Figure 10 (a) and Figure 10 (b) respectively show a side view and a front view of another exemplary embodiment of an angle sensor arrangement and / or magnetic torque sensor arrangement 300 including the magnetic structure 110 and the magnetic field sensor arrangement 320 as described above.

[0176] The main difference between this embodiment and Figure 2 the magnetic field sensor arrangement 220 is that the outer face 204 of the first flux concentrator 301 is provided on a portion 303 of the first flux concentrator 301 that includes a fin-shaped extension member 304, and the outer face 205 of the second flux concentrator 302 is provided on a portion 305 of the second flux concentrator 302 that includes three fin-shaped extension members 306, 307, 308, wherein the fin-shaped extension members 304, 306, 307, 308 extend in a direction substantially perpendicular to the gap direction 206 and exceed the width 209 and / or height 210 of the cross-section of the air gap 203 in a plane perpendicular to the gap direction 206.

[0177] Figure 11 (a), Figure 11 (b) and Figure 11 (c) respectively show Figure 10 a perspective view, a side view, and a front view of the magnetic torque sensor arrangement 300 and the magnetic field sensor arrangement 320 used in combination with the magnetic arrangement 110.

[0178] Figure 12 A flowchart of a method 1200 for stray field immune determination of a signal magnetic flux generated by a signal magnetic field source S1 in a manner highly immune to interference fields is shown. The method includes the following steps:

[0179] a) Providing 1201 a magnetic structure 110 including a magnetic source S1 and two magnetic flux concentrators 111, 112, the magnetic flux concentrators 111, 112 being configured to guide the magnetic flux generated by the source and form an air gap 203 oriented in the radial direction X with respect to the magnetic structure 110;

[0180] b) Measure a first magnetic field component Bx oriented in the radial X within the air gap 203, the first magnetic field component Bx indicating a combination of a signal generated by the magnetic source S1 and a first portion 228 of an interference field S2 oriented in the axial Z with respect to the magnetic structure 110;

[0181] c) Measure a second magnetic field component Bz oriented in the axial Z of the magnetic structure 110 within the air gap 203, the second magnetic field component Bz indicating a second portion 229 of the interference field S2 oriented in the axial Z with respect to the magnetic structure 110;

[0182] d) Reduce or eliminate 1204 the first interference portion 228 by scaling the second signal Bz with a predefined constant K and by subtracting the scaled signal from the first signal Bx.

[0183] Method 1200 may further include step e): Convert 1205 the corrected first signal into an angular distance value and / or a torque value, for example, using a mathematical expression or a look-up table. The angular distance value may indicate the angular distance between the first ring 111 and the second ring 112.

[0184] The method including steps a) to e) is a method for measuring an angular distance and / or a method for measuring a torque value in a manner highly immune to a magnetic interference field.

[0185] Although the magnetic structure 110 has been described so far as being mainly used for a torque sensor, this is not the only application. The magnetic structure 110 can also be used as an angle sensor, particularly for measuring the angle between the first ring 111 and the second ring 112. Accordingly, the present invention also provides an angle sensor capable of measuring the angle between two rotatable rings 111, 112 in a manner highly robust to an external interference field.

[0186] In summary, the magnetic field sensor arrangements 220, 320 and the angle sensor and magnetic torque sensor arrangements 200, 300 disclosed herein are very beneficial for determining the signal magnetic flux generated by the signal magnetic field source S1 without being significantly adversely affected by an external stray field / interference magnetic field. This is due to the specific structure and specific arrangement of the first magnetic flux concentrator and the second magnetic flux concentrator, and the arrangement of the magnetic field sensors in the air gap formed between the two magnetic flux concentrators, particularly by the radial orientation of the gap direction 206 as disclosed herein.

[0187] Although interfering magnetic fields oriented in any direction can superimpose signal magnetic fluxes within the two flux concentrators, the present invention provides means for correcting measurements of both signal magnetic flux and interfering magnetic flux sensed in a first sensing direction (in the gap direction 206) by the steps of: determining the interfering magnetic flux 229 outside the two flux concentrators in a second sensing direction (perpendicular to the gap direction), scaling the amount of interfering magnetic flux sensed in the second sensing direction, and subtracting the scaled amount from the measured magnetic flux in the first sensing direction (gap direction) to substantially obtain the signal magnetic flux generated by the signal magnetic source S1 and optionally modulated by the magnetic structure 110.

Claims

1. A magnetic field sensor arrangement for determining a signal magnetic flux generated by a signal magnetic field source in a manner substantially immune to a magnetic interference field, the magnetic field sensor arrangement comprising: - the signal magnetic field source; - a first magnetic flux concentrator and a second magnetic flux concentrator, the first magnetic flux concentrator and the second magnetic flux concentrator forming an air gap; - a magnetic field sensor, the magnetic field sensor including a plurality of sensor elements; - at least one of the sensor elements, the at least one sensor element being located in the air gap; - a magnetic field sensor, the magnetic field sensor being configured to reduce the influence of the magnetic interference field if the magnetic interference field is present; characterized in that: - the first magnetic flux concentrator and the second magnetic flux concentrator are configured and arranged such that the air gap is formed between an outer face of the first magnetic flux concentrator and an outer face of the second magnetic flux concentrator, wherein the outer face of the first magnetic flux concentrator and the outer face of the second magnetic flux concentrator define a first direction of the air gap by a line of the shortest distance between the outer face of the first magnetic flux concentrator and the outer face of the second magnetic flux concentrator; - the first magnetic flux concentrator and the second magnetic flux concentrator are configured to guide the signal magnetic flux generated by the signal magnetic field source substantially in the first direction to and through the air gap; - the magnetic field sensor arrangement including the plurality of sensor elements is inside the air gap; - the magnetic field sensor is configured to measure a first signal indicative of a magnetic field component oriented in the first direction, and to measure a second signal indicative of a magnetic field component oriented in a second direction substantially perpendicular to the first direction; - the magnetic field sensor is configured to correct the measured first signal by using the measured second signal if the magnetic interference field is present, so as to reduce or eliminate the influence of the magnetic interference field, wherein the magnetic field sensor is configured to reduce or substantially eliminate the influence of the magnetic interference field by scaling the second signal with a predefined constant and by subtracting the scaled signal from the first signal if the magnetic interference field is present.

2. The magnetic field sensor arrangement according to claim 1, It is characterized in that the magnetic field sensor further includes a processor unit and a memory unit.

3. An angle sensor arrangement, comprising: - the magnetic field sensor arrangement according to claim 1 or 2; - a first ring including a plurality of claws, the first ring being arranged adjacent to the first magnetic flux concentrator; - a second ring including a plurality of claws, the second ring being arranged adjacent to the second magnetic flux concentrator; - the first ring and the second ring are movable about a rotation axis and movable relative to each other; - and wherein the magnetic field sensor is further configured to convert the signal magnetic flux into an angular distance signal indicative of an angular distance between the first ring and the second ring.

4. The angle sensor arrangement according to claim 3, Characterized in that, the magnetic field sensor is configured to measure a first magnetic field component in a radial direction with respect to the rotation axis; and wherein the magnetic field sensor is configured to measure a second magnetic field component in an axial direction parallel to the rotation axis.

5. The angular sensor arrangement according to claim 3, It is characterized in that wherein the outer face of the first flux concentrator is provided on a part of the first flux concentrator which has a protrusion or a curved portion or an L-shaped cross-section in a plane containing the rotation axis and the first direction; and / or wherein the outer face of the second flux concentrator is provided on a part of the second flux concentrator which has an L-shaped cross-section in a plane containing the rotation axis and the first direction.

6. The angular sensor arrangement according to claim 5, It is characterized in that, wherein the L-shaped cross-section of the first flux concentrator and / or the second flux concentrator includes a long leg and a short leg, wherein the long leg is longer than the short leg and is oriented substantially perpendicular to the gap direction; and / or wherein the outer face of the first flux concentrator is provided on a part of the first flux concentrator forming the free end of the first flux concentrator; and / or wherein the outer face of the second flux concentrator is provided on a part of the second flux concentrator forming the free end of the second flux concentrator.

7. The angular sensor arrangement according to claim 5, It is characterized in that wherein the outer face of the first flux concentrator is provided on a part of the first flux concentrator including at least one fin-shaped extension member, and / or the outer face of the second flux concentrator is provided on a part of the second flux concentrator including at least one fin-shaped extension member, wherein the at least one fin-shaped extension member extends beyond the width and / or height of the cross-section of the air gap in a direction oriented substantially perpendicular to the first direction, wherein the cross-section of the air gap extends substantially perpendicular to the first direction.

8. The angular sensor arrangement according to any one of claims 3 to 7, It is characterized in that wherein the magnetic field sensor includes a semiconductor substrate which is substantially located inside the air gap and is oriented such that the axial direction parallel to the rotation axis is perpendicular to the semiconductor substrate, and wherein the semiconductor substrate includes an integrated magnetic concentrator IMC and at least two horizontal Hall elements arranged at the periphery of the IMC; or wherein the magnetic field sensor includes a semiconductor substrate which is substantially located inside the air gap and is oriented such that the first direction is perpendicular to the semiconductor substrate, and wherein the semiconductor substrate includes an integrated magnetic concentrator IMC and at least two horizontal Hall elements arranged at the periphery of the IMC; or wherein the magnetic field sensor includes a semiconductor substrate which is substantially located inside the air gap and is oriented such that the semiconductor substrate is perpendicular to the axial direction parallel to the rotation axis, and wherein the semiconductor substrate includes horizontal Hall elements and vertical Hall elements; Or wherein the magnetic field sensor comprises a semiconductor substrate, the semiconductor substrate being substantially inside the air gap and being oriented such that the semiconductor substrate is parallel to the axial direction parallel to the rotation axis and parallel to the first direction, and wherein the semiconductor substrate comprises a first vertical Hall element sensitive in the first direction and a second vertical Hall element sensitive in the axial direction; Or wherein the magnetic field sensor comprises a semiconductor substrate substantially inside the air gap, and the semiconductor substrate is oriented such that the semiconductor substrate is perpendicular to the radial direction with respect to the rotation axis, and wherein the semiconductor substrate comprises a horizontal Hall element and a vertical Hall element.

9. A magnetic torque sensor arrangement for determining a torque applied to a torque rod in a manner substantially unaffected by a magnetic interference field, comprising: - An angle sensor arrangement according to any one of claims 3 to 8; - The torque rod having a first axial end connected to the first ring and a second axial end connected to the second ring such that when a torque is applied to the torque rod, the torque rod elastically deforms, thereby causing angular displacements of the first ring and the second ring as a function of the applied torque; And wherein the magnetic field sensor is further configured to convert the signal magnetic flux or the angular displacement into a torque value.

10. A method for determining a signal magnetic flux generated by a signal magnetic field source in a manner substantially immune to a magnetic interference field, comprising the steps of: a) Providing a magnetic field sensor arrangement according to claim 1 or 2 or an angle sensor arrangement according to any one of claims 3 to 8 or a magnetic torque sensor arrangement according to claim 9; b) Measuring, by the magnetic field sensor, a first signal of a magnetic field component oriented in the first direction; c) Measuring, by the magnetic field sensor, a second signal of a magnetic field component oriented in a second direction perpendicular to the first direction; d) If the magnetic interference field is present, correcting the measured first signal by using the measured second signal so as to reduce or eliminate the influence of the magnetic interference field, wherein step d) comprises: scaling the second signal with a predefined constant and subtracting the scaled signal from the first signal.

11. The method according to claim 10, wherein Step d) is performed by a processor unit and a memory unit integrated in the magnetic field sensor.

12. The method according to claim 10 or 11, characterized in that, The method further comprises the step of: e) Converting the corrected first signal into an angle value.

13. The method according to claim 10 or 11, characterized in that, The method further comprises the step of: e) Converting the corrected first signal into a torque value.

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